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Titanium welded pipe
Original Title: Characteristics of Titanium Welded Pipe Forming Process Titanium welded pipe belongs to roll cold bending forming, which needs to pass through a series of rolls (flat roll, vertical roll, Titanium welding pipe , etc.), and has the characteristics of light weight and thin wall. The forming process includes complex elastic-plastic, large deflection, bending deformation, and includes neutral plane extrusion, shear,titanium round bar, etc. The forming process is complex. The design of roll shape directly affects the quality of welded pipe, and the task of pass design and tool design is arduous In the early stage of titanium welded pipe in China, there was no systematic die design capability. Return to Sohu to see more Responsible Editor:. yunchtitanium.com
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Hot Spot | Breaking
Original Title: Hot Spots | Breaking Foreign Monopoly and Strengthening China's Military Prestige, How Does Xiangtou Jintian, the Leading Titanium Material, Work Hard in the PTA Industry? Wen | our reporter with Li Na Editor | Chen Qiong Zhou Hui probably did not expect that many years later, he would become attached to chemical fibers again. He had worked in the local Development and Reform Commission for many years, and was responsible for the management of the textile port and the non-ferrous metal port. He also served as the vice chairman of Hunan Chemical Fiber Enterprise for many years. During this period, in order to purchase PTA for the enterprise, he traveled abroad to inspect many PTA enterprises in Japan and the United States with advanced technology at that time. But since Zhou Hui put his passion for innovation and enthusiasm into the titanium material industry, the textile and chemical fiber industry, which had accumulated deep emotions, has gradually moved away from his vision. Today, things are changing. One generation of materials and one generation of equipment. This sentence is not only used to describe the important value of carbon fiber in the field of national defense and military equipment, but also to describe the value of titanium materials. As the most growing strategic metal material in the 21st century, titanium alloy is widely used in military, space, ocean and other fields, which is of great significance to promote the high-quality development of China's industrial equipment industry. As an industry with global competitive advantage in China's chemical industry, China's PTA industry is currently more and more closely related to titanium materials, Zhou Hui keenly captured this trend. Zhou Hui felt a different kind of joy when the accumulation of textile and chemical fiber industry in the past converged with her present career. So, what is the intersection of PTA industry and titanium materials in China? How to reflect the application and value of titanium materials in PTA industry? How will Zhou Hui's Xiang Tou Jin Tian do a lot of work in the meantime, and how can he be confident? Recently, the reporter interviewed Zhou Hui, chairman of Hunan Xiangtou Jintian Science and Technology Group Co., Ltd. Application of Titanium Tubes in Large-scale PTA Plant Has Become a Trend After more than 10 years of rapid development and industrial upgrading, China's PTA industry has won a global competitive advantage in terms of capacity scale, plant level, technology and product competitiveness. In 2018, the effective production capacity of PTA in China reached 45.79 million tons, the output was 40.8 million tons, and the self-sufficiency rate reached 99.8%. Large-scale and integrated PTA production plant, leading technology, efficient operation and low energy consumption have also become the distinct characteristics of the current operation of the industry. Expand the full text The production process of PTA includes complex chemical processes such as mixing, hydrogen production, reaction, evaporation, condensation, extraction, separation and drying, as well as processes such as liquid phase conveying, gas phase conveying, gas-liquid mixed phase conveying,ti6al4v, solid-liquid slurry conveying and solid powder conveying. Its production process is also accompanied by high temperature, high pressure, strong corrosion of process media and other prominent characteristics. Influenced by the process and production characteristics, titanium plates and tubes with high performance and corrosion resistance have been widely used in PTA plants in the international market in recent years. Because the titanium alloy has strong corrosion resistance, the corrosion resistance is far superior to that of stainless steel, the resistance to pitting corrosion, acid corrosion and stress corrosion is particularly strong, and the titanium alloy also has excellent corrosion resistance to alkali, chloride, nitric acid, sulfuric acid and the like. At the same time, it has high strength, tensile strength of 686 MPa to 1176 MPa, and density of 4.5 G/cm3, which is only about 60% of steel. Titanium tubes are mainly used for heat exchange tubes of condensers and heat exchangers in PTA plants,titanium filler rod, with high reliability and long service life. In Norway, Japan and other countries, titanium alloy materials are widely used in related devices in the petroleum field. Titanium alloy materials are used in domestic PTA plants in recent years, but titanium alloy materials are mainly imported. The reason is that, on the one hand, the process package of PTA plant in China mainly adopts foreign technologies such as Invista technology and BP technology, so the titanium alloy seamless pipe used in the plant is logically matched with foreign materials. On the other hand, domestic PTA enterprises could not buy domestic titanium welded pipes before, because there was a lack of good titanium strips in China, and high-quality titanium welded pipes were welded with good titanium strips. Finally, a reality is formed that seamless titanium tubes are mostly used in domestic PTA plants. Zhou Hui said: "The key point of titanium welded pipe in PTA plant is to solve the problem of corrosion resistance.". Large plant structure is very complex, so many pipes are gathered together, if the pipeline is corroded, rust and other situations, manufacturers will stop maintenance, which will not only increase operating costs, but also affect the normal production of enterprises in the peak season. In addition, there is a problem of "secondary pollution". Therefore, in recent years, the use of titanium alloy materials in domestic PTA plants has highlighted the urgency. At the same time, from the current trend, the number of enterprises using seamed titanium pipes in PTA plants is gradually increasing. The production of seamed titanium pipes is more environmentally friendly, belongs to clean manufacturing and green manufacturing, and is more convenient and has more economic value. Zhou Hui said. Xiangtou Jintian Leads Domestic Titanium Industry Innovation and Upgrading For a long period of time, what is more uncomfortable than the fact that the domestic titanium welded pipes needed by PTA plants can not be supplied independently is that the titanium materials needed by our national defense industry can not be self-sufficient. Many people may not think that foreign countries once implemented "neck jam" in the field of titanium materials. It is imperative to conquer the domestic innovative technology of titanium materials, and Hunan Investment Jintian has made a breakthrough in this field and become a rising star of foreign technology. Compared with some titanium material enterprises that have been established for decades, Hunan Investment Jintian, which has only 10 years of history, titanium tubing price ,ti6al4v eli, is a "recruit" in the domestic titanium industry. However, with a series of innovative technologies, this "recruit" has grown rapidly into one of the "top three" titanium enterprises in China, forming an international advanced and domestic first-class titanium industry platform. Its R & D and production of large coil weight wide titanium strip, high performance titanium welded pipe, high performance titanium alloy bar and other core technology products fill the domestic gap and break the foreign monopoly. At present, the annual production capacity of Xiangtou Jintian Titanium Belt is 10000 tons, and the annual production capacity of titanium pipe is 5000 tons, which is the first in Asia and the second in the world. Behind the glory, there is often an unknown story of hardship. At first, we knew titanium processing was difficult, but after 10 years, we didn't expect it to be so difficult. At that time, there was a lack of technology, talent and resources, and we were "recruits", so what should we do? Innovation must be accelerated. At that time, we were full of ambition and set a goal for ourselves-to fill the gap in the domestic market, the titanium steel joint model we created was an innovative move. However, in the process of creation, we have no experience to draw lessons from, so we can only work, explore and summarize at the same time. How many days and nights, we have been insisting on it. One night in 2007, a product was finally developed successfully, and before that, the company had gone through a whole year of exploration and repeated 32 experiments. At that time, the most difficult thing was that we did not match the standard. Although Japanese enterprises had technology, they kept it strictly confidential to our country. Ultimately, we rely on independent research and development to find a way of our own. Recalling those hard, muddy and passionate days, Zhou Hui is still full of emotion. All the efforts are obviously worth it. At present, Hunan Investment Jintian's products have successfully entered the "national team" phalanx and become the core supplier of China's large aircraft, nuclear power, ships and other strategic markets. The application of titanium alloys in naval submarines and other fields can reduce weight and improve corrosion resistance. Since the year before last, the application of titanium materials in submarines, aircraft carriers and other fields in China has been led by Hunan Investment Jintian. A large number of titanium alloys are used in the engine components, skeleton and other parts of the aircraft, and about 50% of the titanium materials currently used in domestic large aircraft come from Hunan Investment Jintian. At the same time, Hunan Investment Jintian is also the only Chinese supplier of high-performance titanium strips and tubes in the international market in the fields of energy, desalination, marine engineering and so on. It takes ten years to sharpen a sword. At present, we are the only Chinese titanium material enterprise that can compete in the international titanium strip market. Now it is said that our technology is stuck in the neck of others, but in the field of titanium belt, we have the ability to block the neck of others. Speaking of this, Zhou Hui's tone was obviously excited, "When we get together, we all feel very proud, and the sense of value and achievement of serving the country by industry suddenly comes to mind." Promote domestic PTA plant to be more refined When the application in the military industry and desalination market gradually opened up, and when the output of enterprises gradually increased, Zhou Hui began to think about how to adjust the product structure, and PTA, which connects chemical industry and chemical fiber, entered his field of vision. Zhou Hui said: "Our products will mainly realize three substitutions in the field of PTA equipment in China: the first is to replace imports, the second is to replace titanium alloy seamless tubes, and the third is to realize the substitution of titanium alloy materials for other materials." It is reported that the titanium welded pipe forming deformation rebound compensation technology developed by Hunan Investment Jintian can meet the technical requirements of titanium welded pipe for PTA plant. The high efficiency heat exchange titanium welded tube developed for the first time can realize the special-shaped strengthening and multi-dimensional structural strengthening of titanium heat exchange tube. Through chemical composition, metallographic structure, mechanical property, process performance test, size and precision inspection and nondestructive testing, all indexes of the product can meet the requirements of the titanium tube standard for PTA and the ASTMB338 standard, and can replace the seamless titanium tube for PTA heat exchange. In the previous appraisal of technical achievements organized by the Ministry of Science and Technology Development of China Textile Industry Federation, the expert group agreed that its achievements were innovative, had independent intellectual property rights, reached the international advanced level, broke the long-term dependence on imports of titanium welded pipes in China, and realized the autonomy of the whole industrial chain of low hydrogen and low iron titanium products. If we look at the performance-price ratio, at present, while the product quality remains stable, the price of Xiangtou Jintian Titanium Welded Pipe is 20% -30% lower than that of Japanese enterprises. This will reduce the investment cost for domestic PTA production enterprises using seamed titanium tubes. On this basis, enterprises may also need to use another way of thinking to consider the investment output ratio. Zhou Hui explained: As a strategic material, the greatest advantage of titanium material is that it can realize the concept of the whole life cycle of products. For example, when it is used in marine engineering, it will not rust even after ten thousand years, which is why titanium alloys are used in marine competitions between countries. PTA belongs to the field of civil industry, some enterprises may feel that titanium welded pipe is more expensive, but once used, they feel very good. In our research, we met an enterprise that used titanium alloy in a set of devices in 1994, and there has been no problem in operation so far. Therefore, the accounts of enterprises using titanium welded pipes should be calculated according to the whole life cycle, not just in front of them. In addition, the use of welded titanium pipes in PTA plants will further improve the quality of PTA products. The complex production process from PX to PTA is accompanied by a large number of high-temperature reactions, especially in the condenser to complete a large number of heat exchanges. The use of welded titanium tubes can reduce the wall thickness of the condenser, accelerate the heat dissipation of the condenser, and thus improve the exchange efficiency. According to reports, the wall thickness of the seamed titanium pipe produced by Xiangtou Jintian is getting thinner and thinner, which is only 0.2 mm at present. PTA is one of the important application markets of titanium tube in civil field. With the continuous upgrading of materials,titanium exhaust tubing, there is still much to be done in the refinement of PTA plants in China. We hope to expand the use of titanium tubes in PTA plants, but also to improve the profit margin of PTA enterprises. We are confident that together with PTA enterprises and related equipment enterprises, we will do a better job in the refinement of PTA plants and production in China and further promote the high-quality development of PTA industry. Zhou Hui is confident about the application and expansion of seamed titanium tubes in PTA plants. Return to Sohu to see more Responsible Editor:. yunchtitanium.com
Original Title: How Thin Is the World's Thinnest Made by 12.64 Million? | Consumer Goods Investment Recommendation of the Week This report monitors and studies the one-month situation of the current consumer goods market, and screens out five consumer goods with large fluctuations. Please pay attention to them: RICHARD MILLE X Ferrari RM UP-01 Ferrari Slim Watch Market Price: $1,880,000 In order to celebrate the long-term cooperation with Ferrari, Swiss high-end watchmaking brand "RICHARD MILLE-RICHARD MILLE-Ferrari" recently launched an ultra-thin watch RM UP-01 Ferrari together with luxury car brand "FERRARI-Ferrari". The RM UP-01 Ferrari is only 1.75mm thick, breaking Bulgari's 1.8mm record a few months ago. The case is made of five-grade titanium alloy and weighs 30 grams (including the strap). It is equipped with an integrated manual winding movement. The movement is 1.18mm thick and can be stored for 45 hours. It is limited to 150 pieces. The two brands are outstanding in their respective fields, and the watches launched in this cooperation can be called industrial boutiques. You may collect them if you have the strength. Investment Rating: Buy Target Price: $1,880,3d titanium wire,000 Risk level: R4 Expand the full text Dior Maison New Handmade Surfboard Market Price: $10,000 Summer is a great time to play on the beach, so Dior Maison,nickel titanium wire, the home accessories line of the luxury brand Dior, launched the Dioriviera resort collection designed by Maria Grazia Chiuri, the creative director of women's wear. In addition to new products such as inflatable floating boards, outdoor umbrellas and summer fans, it includes a handmade surfboard. Designed by surfing professionals and produced in the Basque region of France, this board pays tribute to the spirit of freedom and adventure. It has been carefully built through layers of processes, titanium sheet grade 5 ,titanium bar grade 5, properly shaped and smoothed, and covered with a classic Toile de Jouy print in fluorescent blue, as well as the "CHRISTIAN DIOR" logo. In the past two years, the product line of luxury goods has developed comprehensively, often introducing some simple and luxurious items, so that a large number of fashion enthusiasts can pay for them. There is always a lot of room for premium with brand support. You may pay attention to it. Investment Rating: Buy Target Price: $10,000 Risk level: R3 Herm Hermès Urban Luxury Bike Market price: $23,600 Recently, the special customization department of the French luxury brand "Herm Hermès-Hermes" launched a unique Hermes Odyssee Terre bicycle, inspired by the compact bicycle in Japan, which is light in the city and has simple lines. The body of this urban lightweight bicycle is made of ash wood, aluminum and spad leather. The seat is printed with Hermes Paris logo. The cream body is matched with light brown seat and Hermes iconic orange wheels. The body is equipped with four transmission gears. The overall size of the bicycle is 39.5 inches long and 22.8 inches wide. Weighs 24.2 pounds and has an adjustable seat height for all riders. Although it started with the production of harness related products, in order to meet the needs of customization, the special customization department of Hermes can always use the top materials and technology to create unique customized products, which can be paid attention to by senior collectors of Hermes. Investment Rating: Buy Target Price: $23,600 Risk level: R3 Supreme X UMBRO co-branded football Market Price: $110 The introduction, price trend and investment advice of this investment product have been updated on the "DUSHAOFEI APP" and "DUSHAOFEI" websites. Cabana X Artist Daniel Arsham Limited Edition Scented Candle Market price: ¥ 1299- ¥ 1999 The introduction, price trend and investment advice of this investment product have been updated on the "DUSHAOFEI APP" and "DUSHAOFEI" websites. Please go to the IOS or Android Market Mainstream App Store to search and download "DUSHAOFEI APP" to view the complete version of investment products and the complete information of previous articles. Prompt: The above information only supplies the reference, the investment has the risk, enters the market to need to be careful. Return to Sohu to see more Responsible Editor: (function() { function getBrandHtml() { var brands = [],titanium filler rod, html = ''; for(var i = 0; i < brands.length; i++) { var brand = brands[i]; if(brands.length i+1) { html+= ''+brand.name+''; } else { html+= ''+brand.name+'、'; } } return html; }; if(document.getElementById('linkBtn')){ document.getElementById('linkBtn').onclick = function() { $('#brands').removeClass('brand');$ ( '# tipInfo').text ( 'Real name responded'); $ ('#linkBtn').remove();$ ('.real-response .content').css('line-height', '20px');$ ('.real-response .time').css('line-height', '20px'); }; document.getElementById('brands').innerHTML = getBrandHtml(); }; })();。 yunchtitanium.com
Original Title: Titanium and Titanium Alloy Materials in Dental Implant Applications 1. Pure titanium Since Branemark put forward the theory of osseointegration, pure titanium and titanium alloys (mainly Ti-6Al-4V) have been the preferred materials for dental implants. Studies have found that pure titanium has good biocompatibility and corrosion resistance, as well as excellent mechanical properties, including hardness, tensile strength, yield strength and fatigue strength, which can meet the functional requirements of dental implants. It has been widely used in clinical as an implant material and has achieved good restoration results. However, the dark color of titanium can penetrate the thin mucosa at the implant site, thus affecting the aesthetic effect of thin-gingival patients. The elastic modulus of titanium is higher than that of human bone, and the elastic modulus of titanium is 110 GPa. The elastic modulus is 20 to 30 GPa, and bone resorption may occur due to stress shielding. With the increase of clinical application, recent studies have found that pure titanium implants have the risk of peri-implantitis, which can release titanium ions to participate in gingival inflammation and periodontal inflammation. In addition, titanium may have immunogenicity, as an allergen, causing type IV hypersensitivity to metal implants in some allergic patients. Therefore, scholars at home and abroad have been devoting themselves to the research and exploration of dental implant materials with more ideal performance in all aspects,titanium tubing price, which can replace pure titanium. 2. Titanium alloy After pure titanium implant was widely used in clinic, titanium alloy dental implant materials were gradually developed. Compared with pure titanium, the addition of alloying elements can improve the corrosion resistance and machinability of the material, reduce the elastic modulus, and reduce the risk of fracture, especially for narrow-diameter implants. Ti-6Al-4V alloy is widely used in clinical practice. In recent years,titanium sheet grade 5, related studies have found that Ti-6Al-4V alloy can release very small amounts of vanadium and aluminum ions, which can cause harm to human body, such as Alzheimer's disease, peripheral neuropathy and osteomalacia. Therefore, scholars began to focus on the development of non-toxic titanium alloys. Beta-type titanium alloying elements such as Nb, Zr, Ga, Mo, Pd, Se, Sn, Ta, ti6al4v ,titanium exhaust tubing, Ge, etc. Are considered to be safe and non-toxic alloying elements. Therefore, in the process of seeking more ideal implant materials, the alloying of titanium has become one of the research hotspots in this field. 2.1 Titanium Zirconium Alloy (Ti-Zr) Zirconium and titanium belong to the same main group. They have similar physical and chemical properties: both have excellent corrosion resistance, super high mechanical strength and excellent plasticity, and have no toxic effects on body tissues. 2.2 Titanium-niobium alloy (Ti-Nb) Titanium-niobium alloys have attracted more and more attention because of their excellent corrosion resistance and biocompatibility. Studies have shown that titanium-niobium alloy has sufficient corrosion resistance and biocompatibility, can promote bone formation, and has the potential to become an implant material, but its mechanical properties need to be confirmed by scholars. 2.3 Titanium-aluminum-niobium alloy Ti-6Al-7Nb alloy was developed because scholars were worried that Ti-6Al-4V alloy would release toxic vanadium ions and cause adverse reactions to human body. Ti-6Al-7Nb alloy is non-toxic and has similar mechanical properties to Ti-6Al-4V alloy, and its corrosion resistance is also strong. In recent years, it has gradually come into the sight of dental implant scholars. The results show that Ti-6Al-7Nb alloy not only retains the good mechanical properties of Ti-6Al-4V alloy, but also has better biocompatibility, biosafety and corrosion resistance, which is more conducive to the adhesion and proliferation of osteoblasts, and the bone integration ability is equivalent to that of pure titanium. Expand the full text 2.4 Titanium niobium tin alloy (Ti-Nb-Sn) The elastic modulus of Ti-Nb-Sn alloy is about 40 GPa, and it has no cytotoxicity, good corrosion resistance and bone histocompatibility. Titanium-niobium-tin alloy has the same biological potential and bone bonding energy as pure titanium Force. 2.5 Titanium Tantalum Zirconium Alloy (Ti-Ta-Zr) After the Ti-Ta-Zr alloy is synthesized, tantalum can reduce the elastic modulus of the material, and zirconium can improve the corrosion resistance. Compared with pure titanium, Ti-Ta-Zr alloy has lower elastic modulus, better corrosion resistance and hydrophilicity, and better osseointegration ability, which is expected to become a substitute for pure titanium implant materials. 2.6 Titanium niobium zirconium alloy (Ti-Nb-Zr) Ti-Nb-Zr alloy has excellent ductility, elastic modulus of 79 GPa, excellent plastic deformation ability, good mechanical properties and biocompatibility. Titanium-niobium-zirconium alloy has excellent mechanical properties, biocompatibility and corrosion resistance, and has the potential to become a candidate material for dental implants. 2.7 Titanium niobium zirconium tin alloy (Ti-Nb-Zr-Sn) Ti-Nb-Zr-Sn alloy is a new titanium alloy with high strength and low elastic modulus. According to Nune et al., Ti-24Nb-4Zr-8Sn alloy is expected to be used clinically in the future because of its unique chemical properties and high hydrophilicity, which is conducive to the adhesion, proliferation, differentiation, mineralization of osteoblasts and the synthesis of related proteins. 2.8 Ti-Nb-Ta-Zr alloy Titanium-niobium-zirconium-tantalum alloy has similar histocompatibility with Ti-6Al-4V alloy, which can promote the proliferation of osteoblasts and increase the activity of alkaline phosphatase. Therefore, Ti-Nb-Ta-Zr alloy has the potential to become an alternative material for pure titanium implants. 2.9 Titanium niobium zirconium tantalum silicon alloy (Ti-Nb-Zr-Ta-Si) In recent years, a new type of five-phase titanium alloy, Ti-Nb-Zr-Ta-Si alloy, has been gradually developed and studied by dental implantologists. The results showed that the osseointegration ability of Ti-Nb-Zr-Ta-Si alloy implants was equivalent to that of pure titanium,3d titanium wire, which could increase the mineralization deposition rate of surrounding bone in the early stage after implant implantation. However, scholars have only done a preliminary study, and the mechanical properties and corrosion resistance of the material need to be further studied and confirmed. Source: Research Status of New Materials for Oral Implants Return to Sohu to see more Responsible Editor:. yunchtitanium.com
Original Title: Baotai Co., Ltd. Enters the Field of Titanium for Hydrogen Fuel Cell Recently, Baoti and the State Power Investment Corporation successfully signed the "National Demonstration City Joint Declaration Enterprise Cooperation Letter of Intent" project and the first batch of titanium material procurement contracts, marking Baoti's entry into the new titanium application field. The project actively promotes the construction of fuel cell vehicle industry demonstration city clusters in Beijing-Tianjin-Hebei, Hubei, Zhejiang and other regions, and provides core technical support for the research and development of related basic materials and key components, as well as the development of the national fuel cell vehicle industry. As early as 2017, Baoti shares have been laid out ahead of schedule, Baoti Research Institute and related units set up a hydrogen energy project team, according to the national strategy and future market demand, began to research and develop titanium technology for hydrogen fuel cells. During this period,Titanium 6Al4V wire, Baoti Project Team closely focused on the performance requirements of hydrogen fuel cell metal bipolar plate, actively overcome difficulties and repeated tests. In October 2019, the titanium bipolar plate was successfully applied on the first new energy hydrogen bus, which fully met the design requirements after later testing. On September 27, 2020,Titanium welding pipe, the hydrogen fuel cell product release conference was held in Ningbo, and Baoti was invited to attend the conference and ushered in new development opportunities. About titanium bipolar plates Titanium and titanium alloys have high application value in hydrogen fuel cell bipolar plates because of their low density, high specific strength and excellent corrosion resistance in acidic environment. As an important part of PEMFC, bipolar plate accounts for more than 70% of the weight of the stack, about 50% of the volume, and its cost is about 30% to 50% of the cost of the battery. Bipolar plate materials are mainly divided into three categories, namely graphite bipolar plate, composite material bipolar plate and metal bipolar plate. Graphite bipolar plate has light weight, good corrosion resistance and excellent electrical and thermal conductivity, titanium plate gr7 ,titanium round bar, but it has high brittleness and high cost of flow field processing. Composite bipolar plate has excellent formability And has high mechanical strength, poor conductivity and high proces cost; and in comparison, that metal bipolar plate is thin. It has excellent electrical and thermal conductivity, high mechanical strength and good gas isolation, which is conducive to the improvement of the specific power density of the battery. In addition, the metal material processing technology is mature, and high-precision complex flow fields can be processed by stamping, die-casting and laser forming, which is easy to achieve the quantitative production of the plate. It has become the mainstream bipolar plate material for hydrogen fuel cells. Metallic bipolar plate materials are generally divided into stainless steel, aluminum alloy and titanium alloy, among which the corrosion resistance of titanium in PEMFC environment is better than that of stainless steel and aluminum alloy, and its high specific strength can further reduce the weight of the plate and improve the specific power density of PEMFC. For example, Toyota MIRAI fuel cell vehicle in Japan uses titanium as bipolar plate material and adopts 3D mesh flow field structure design. Compared with stainless steel straight flow field bipolar plate, its stack mass power density and volume power density have been greatly improved. At present, cost and durability are two important issues that restrict the commercialization of hydrogen fuel cells, and the cost of bipolar plates is determined to a certain extent by plate materials, flow field processing and plate coating preparation process. Graphite and carbon-based composites can no longer meet the requirements of hydrogen fuel cells in terms of performance, and metal materials have become the mainstream materials for bipolar plates of hydrogen fuel cells. In addition, high power has always been the goal of hydrogen fuel cells. Titanium and titanium alloys in metal materials have low density and high specific strength, and have excellent corrosion resistance in hydrogen fuel cells, which can significantly reduce the weight and volume of bipolar plates, thus significantly improving the mass specific power and volume specific power of the cells. Moreover, the corrosion products produced by titanium and titanium alloys in the long-term service process have weak toxicity to proton exchange mode and catalyst, which is conducive to improving the stability and durability of battery operation. Metallic carbon/nitride and amorphous carbon coatings on the surface of titanium bipolar plate have excellent comprehensive performance and high research and application value.However, these coatings are prone to pinhole defects, so the main goal of current research is to improve the compactness, adhesion strength and surface conductivity of the coating. In addition, the coating should have good hydrophobicity to promote the drainage of water generated by the reaction. In order to meet these comprehensive properties, higher requirements are put forward for the structure design and composition of the coating. The composite and nanocrystallization of the coating structure can improve the compactness,titanium bar gr5, corrosion resistance and conductivity of the coating to a certain extent, and enhance the service stability and reliability of titanium plates, which is the main direction of future development. Source | Hydrogen Club Return to Sohu to see more Responsible Editor:. yunchtitanium.com
Original Title: Special Properties of Nitinol Special Properties of Nickel-Titanium Alloy 1. Shape memory characteristics Shape memory is that when the parent phase of a certain shape is cooled from above Af temperature to below Mf temperature to form martensite, the martensite is deformed below Mf temperature, and then heated to below Af temperature, accompanied by reverse phase transformation, the material will automatically restore its shape in the parent phase. In fact, the shape memory effect is a thermally induced phase transformation process in NiTi alloys. 2. Superelastic The so-called superelastic refers to the phenomenon that the sample produces a strain far greater than the elastic limit strain under the action of external force, and the strain can be automatically restored when unloaded. That is to say, in the parent phase state, due to the external stress,titanium round bar, the stress-induced martensite transformation occurs, so the alloy shows different mechanical behavior from ordinary materials, its elastic limit is far greater than that of ordinary materials,titanium bar gr7, and it no longer obeys Hooke's law. In contrast to shape memory properties, superelasticity is not thermally involved. In a word, hyperelasticity means that the stress does not increase with the increase of strain within a certain range of deformation, and the clinical manifestation is that the orthodontic force generated by the archwire in the process of deformation remains constant and no longer gradually loses with the movement of teeth towards the orthodontic direction. According to the characteristics of the stress-strain curve corresponding to hyperelasticity, hyperelasticity can be divided into two types: linear and nonlinear hyperelastic. In the stress-strain curve of the former, the relationship between stress and strain is nearly linear. Nonlinear hyperelasticity is the result of stress-induced martensitic transformation and its reverse transformation during loading and unloading in a certain temperature range above Af, so nonlinear hyperelasticity is also called phase transformation pseudoelasticity. The phase transformation pseudoelasticity of NiTi alloy can reach about 8%. The superelasticity of nitinol varies with the conditions of heat treatment, nickel titanium wire ,titanium tubing price, and begins to decrease when the archwire is heated above 400 oC. When the heat treatment temperature exceeds 600oC, the superelasticity is substantially small. According to this characteristic, the non-orthodontic area of the archwire can be thermally treated to lose its superelasticity in clinic, so as to avoid the influence of the orthodontic process on the teeth in the non-orthodontic area, and the archwire in the orthodontical area still has good elasticity. 3. Sensitivity of temperature change in oral cavity: The orthodontic force of stainless steel wire and CoCr alloy orthodontic wire is basically not affected by the temperature in oral cavity. The orthodontic force of the superelastic NiTi alloy orthodontic wire varies with the oral temperature. When the deformation is constant. The orthodontic force increased with the increase of temperature. On the one hand, it can accelerate the movement of teeth, because the temperature change in the oral cavity will stimulate the blood flow in the blood stasis area caused by the capillary stagnation caused by the orthodontic device, so that the repair cells can be fully nourished during the movement of teeth to maintain their vitality and normal function. On the other hand, orthodontists cannot precisely control or measure the orthodontic force in the oral environment. 4. Corrosion resistance: Studies have shown that the corrosion resistance of nickel-titanium wire is similar to that of stainless steel wire. 5. Toxicity resistance: Nickel-titanium shape memory alloy has a special chemical composition, that is, it is a nickel-titanium alloy containing about 50% nickel, which is known to have carcinogenic and cancer-promoting effects. In general, the surface layer of titanium oxide acts as a barrier, which makes the Ni-Ti alloy have good biocompatibility. TixOy and TixNiOy in the surface layer can inhibit the release of Ni. 6. Gentle orthodontic force: The currently used orthodontic wires include austenitic stainless steel wire, cobalt-chromium-nickel alloy wire, nickel-chromium alloy wire, Australian alloy wire, gold alloy wire and nickel-titanium alloy wire. Load-displacement curves for these orthodontic wires under tensile and three-point bending test conditions. Nitinol has the lowest and most flat plateau of the unloading curve, indicating that it provides the most durable and gentle orthodontic force. 7. Good shock absorption characteristics: The greater the vibration of the arch wire caused by chewing and bruxism, the greater the damage to the root and periodontal tissue. Through the study on the attenuation experiment of different archwires, it is found that the vibration amplitude of stainless steel wire is larger than that of superelastic nickel-titanium wire, and the initial vibration amplitude of superelastic nickel-titanium archwire is only half of that of stainless steel wire. The good vibration and shock absorption characteristics of archwires are very important for the health of teeth,ti6al4v eli, while traditional archwires, such as stainless steel wires, tend to aggravate root resorption. Contact us Back to Sohu to see more Responsible Editor:. yunchtitanium.com
Original Title: [Blue Book of Medical Devices] Current Situation and Development Trend of Orthopedic Implant Industry in China [Editor's Note] This article is excerpted from China Medical Device Industry Development Report (2021) B14, written by Xu Shufu, General Manager of Zhengtian Business Department of Beijing Natong Technology Group Co., Ltd., and Li Renyao, General Manager of Orthopaedics Department of Beijing Natong Technology Group Co., Ltd. [Abstract] The sudden outbreak of COVID-19 at the end of 2019 has caused great losses to the global medical device market, brought new opportunities and development directions, and promoted the transformation of the medical device industry from low-end to high-end. On the one hand, companies have increased their investment in technological innovation, on the other hand, the smart medical model has gained unprecedented opportunities for development in the epidemic. At the same time, in 2020, all provinces in China will carry out purchasing with quantity, change the profit structure, and then promote the adjustment of market structure and the centralization of the industry. The promulgation of a series of regulations on the supervision of medical devices and the implementation of the unique identification code (UDI) of medical devices indicate the improvement of the supervision of medical devices and the tightening of quality control in China, while the registration certificate holder system brings new opportunities for the development of medical device companies, especially new companies. In 2020, China's orthopedic medical device market reached 29.8 billion yuan, and the localization rates of trauma, spine and joint reached 72%, 54% and 47% respectively. With the maturity of domestic enterprises'technology, the localization rate will be further improved, and innovation is still the source of power for the sustainable development of orthopaedic medical device market in China. [Key words] aging; localization rate; purchasing with quantity; digital orthopaedics [Good News]: Report on the Development of China's Medical Device Industry (2021), the fifth volume of the Blue Book of Medical Devices, was created by the China Institute of Drug Administration and published by the Social Sciences Academic Press, with Wang Baoting and Geng Hongwu as the chief editors and Yu Qingming, Jiang Haihong and Li Qiang as the deputy editors. The report was published in September. (Text below) The "14th Five-Year Plan" put forward by the Fifth Plenary Session of the Nineteenth Central Committee points out the direction for the development of China's medical device industry, and also puts forward higher requirements. With the promulgation of a series of government policies, regulations and regulations, including the Outline of the "Healthy China" 2030 Plan, the Regulations on the Supervision and Administration of Medical Devices, the Notice on the Pilot Work of Expanding the Medical Device Registrant System, and the Pilot Work Program of the Medical Device Unique Identification System, we have strengthened the supervision of medical devices. It also provides a good external environment for the innovation and development of medical devices from the policy aspect. Based on the objective environmental factors and policy guidance, this paper focuses on the research and analysis of the development situation, hot spots, new technologies and trends of orthopaedic medical device industry in 2020, in order to provide reference for the healthy and sustainable development of the industry. I. Overview of China's Orthopaedic Medical Devices Market in 2020 (I) Market Overview Expand the full text Large population base and aging population are the basic national conditions of China at the present stage. In 2022, the population over 65 years old will account for 14% of the total population, and will reach 28% by the middle of this century [2]. The elderly are a high-risk group with low bone mass, and osteoporosis is an important factor leading to fracture. In bone-related orthopedic diseases (such as osteoarthritis, vertebral compression fracture, osteoporosis, etc.), the elderly account for nearly 50%, and in fracture patients, the elderly account for 1/3. In the future, the number of orthopedic patients in China will continue to grow with the increase of the elderly. With the modern working lifestyle, the improvement of quality of life and the expansion of sports groups, the probability of orthopaedic injuries is also increasing, including fractures caused by traffic accidents, cervical and lumbar diseases, soft tissue injuries and so on. China's GDP ranks second in the world and grows fastest, but in terms of government health expenditure, China accounts for less than 5% of GDP, while the United States accounts for 16.9% of its GDP [3]. With the proposal of "Healthy China", our government has accelerated the promotion of the universal health insurance system, and the proportion of health expenditure will continue to increase. With the expansion of patient scale and the coverage of medical insurance payment, it is foreseeable that the orthopaedic market in China will continue to expand in the future. In recent years, with the release of a series of policies and regulations, our government adjusts the contradiction between the growing demand of patients and the supply of medical devices through macro-control, so as to maximize the limited resources to serve the people. Especially for domestic leading enterprises, based on the low degree of centralization of Chinese enterprises, under the promotion of a series of policies such as "two-invoice system" and purchasing with quantity, fee control, price reduction and domestic penetration will promote the centralization of leading enterprises in the industry. This is the best opportunity for China's orthopaedic implant industry to upgrade and penetrate the domestic market. While strengthening the innovation and development of medical devices, we should also strengthen the strict supervision of medical devices. China will grasp the healthy and sustainable development of medical devices from the perspective of encouragement and supervision. (II) Industry segmentation In 2020, China's orthopedic implant market reached 29.8 billion yuan, an increase of 10% over the previous year. The main segments are trauma, spine, joint and sports medicine (see Table 1). According to the information published on the website of the National Medical Products Administration, a total of 237 orthopaedic Class II and Class III registration certificates were approved in 2020, including 202 domestic (including Hong Kong and Taiwan) and 35 imported [4]. 1. Trauma In 2020, a total of 76 registration certificates were approved by NMPA,titanium seamless tube, including 74 domestic ones and 2 imported ones. Affected by the COVID-19 epidemic, the growth rate of the trauma market, which is dominated by elective surgery, such as spine and joints, has slowed down significantly. Imported trauma showed a negative growth due to factors such as the third-level hospitals as the main line-ups for anti-epidemic and the purchase of trauma belts. In the domestic trauma market in 2020, imports accounted for 28%, with a growth rate of -5%; domestic products accounted for 72%, with a growth rate of 13%. In the future, degradable material solutions will be the main development direction of the trauma market. 2. Spine In 2020, 71 registration certificates were approved by NMPA, including 61 domestic and 10 imported. In 2020, there was no provincial-level purchase with quantity in the domestic spine market, and the joint market was less affected by price reduction. Also affected by the novel coronavirus epidemic and the anti-epidemic of the third-level first-class hospitals, the imported spine showed a negative growth. In the domestic spine market in 2020, imports accounted for 46%, with a growth rate of -2%; domestic products accounted for 54%, with a growth rate of 22%. In recent years, microscopic fusion, 3D printing and navigation robots have become the focus of attention in the field of spine, and are also the key development direction of spine in the future. 3. Joints In 2020, there were 54 registration certificates approved by NMPA, including 43 domestic ones and 11 imported ones; 37 registration certificates related to hip joints, 11 registration certificates related to knee joints and 6 others. Joints account for the highest share in the field of orthopaedic subdivision. As joint surgery is mainly elective surgery, the number of joint surgery has been steadily increased with the improvement of epidemic control. Affected by the price reduction of purchasing in Yunnan, Anhui, Jiangsu and Zhejiang,6al4v titanium bar, the growth rate of the joint market has slowed down to a certain extent. In the domestic joint market in 2020, imports accounted for 53%, with a growth rate of 4%; domestic products accounted for 47%, with a growth rate of 16%. In the future, it will be one of the trends in the joint market to increase market share through digital solutions, including robot-assisted surgery. 4. Sports medicine In 2020, Yunyi obtained a total of 32 registration certificates approved by NMPA, including 23 domestic ones and 9 imported ones. Sports medicine is the fastest growing segment of the orthopaedic market. Traditional orthopaedic enterprises and emerging enterprises have laid out the market one after another. In the domestic sports medicine market in 2020, imports accounted for 92%, with a growth rate of 23%; domestic products accounted for 8%, with a growth rate of 66%. At present, sports medicine solutions in the domestic market mainly focus on traditional anchors, interface screws, titanium plates with loops and other implants, which are used to solve more than 80% of basic arthroscopic surgery. Artificial ligament and biological tissue engineering related products have become indispensable solutions in the future layout of manufacturers, and are better choices for soft tissue injury repair. Second, the current hot spot of orthopaedic medical device market in China (I) Policies & regulations 1. Purchase with quantity In July 2019, the General Office of the State Council issued the Reform Plan for the Control of High-value Medical Consumables (No.37 issued by the State Office), which clearly explored the centralized procurement of high-value medical consumables in accordance with the principles of purchasing with quantity and linking quantity with price. This will not only lead to the change of profit structure and the reduction of profit margin, but also bring opportunities for the improvement of localization and industry centralization, and domestic leading enterprises will be the biggest beneficiaries. Since 2019, Yunnan, Anhui, Jiangsu, Zhejiang and Shandong have successively carried out the work of purchasing with quantity. Among them, the average decrease of joint purchasing in Anhui has reached 81%, the average decrease of spine has exceeded 50%, and the highest decrease has reached 95%. The average decrease of artificial hip prosthesis in Jiangsu is 47%; Shandong joint procurement, the average decline of more than 86%, while the lowest price of pottery to pottery products dropped to 4800 yuan, the highest reduction of trauma reached 94%, the average price of universal locking bone plate was 2200. In the provinces where purchasing with quantity has been carried out, the average price drop is about 50%, while the largest single product drop is more than 85%. From the perspective of bid-winning enterprises, import enterprises have an average of 1-3 bid-winning enterprises in purchasing with quantity in each province, while domestic enterprises have been selected more than 10 in each province, of which leading enterprises have won more than 80%. In 2021, in the face of the upcoming second batch of national unified procurement with quantity, orthopaedic enterprises need to actively improve talent management and innovative technology, develop differentiated products, so as to improve product quality and brand competitiveness, and maintain their sustainable development. 2、UDI The unique identification of medical devices (UDI) is the identity card of medical devices and the code to identify the uniqueness of medical devices. UDI system plays a positive role in realizing the transparency of all aspects of the whole life cycle of medical devices and improving the traceability of medical devices. The "Key Tasks for Deepening the Reform of Medical and Health System in the Second Half of 2020" issued in 2020 (No.25 issued by the State Office) put forward that some key varieties such as high-value medical consumables should be selected to implement the unique identification of medical devic es, so as to link up their codes in registration, sale and use, so as to make them unique. To realize the unified management of the production and circulation of medical device consumables. Since the publication of the Pilot Work Program of the Unique Identification System for Medical Devices National Health Commission in 2019, the pilot work of UDI in China has been officially launched. According to the current needs of medical and health reform, 69 varieties of 9 categories, including bone joint implants, spinal implants and joint replacement implants, were selected as the first batch of medical devices. Select 108 users and 116 production and operation enterprises including 23 orthopaedic enterprises such as Tianjin Zhengtian Medical Devices Co., titanium plate gr7 ,Titanium 6Al4V wire, Ltd., Shandong Weigao Haixing Medical Devices Co., Ltd., Beijing Aikang Yicheng Medical Devices Co and Dabo Medical Technology Co as the first batch of pilot units for the sole identification of medical devices. Since the pilot work was carried out, all parties have actively participated in and worked together to basically build a unique identification system framework and a unique identification data platform. The pilot orthopedic enterprises have basically realized the functions of unique identification creation, code assignment and data upload. The next step is to carry out the global pilot of unique identification according to the work deployment, and explore and expand the application of unique identification in medical treatment, medical insurance, supervision and other fields. The construction of UDI system is a systematic project to lay a foundation for long-term benefits. Orthopedic implant enterprises should carry out the implementation of unique identification as early as possible, actively explore the application mode of UDI in product traceability and other fields, and give full play to the application value of UDI. (II) Application of new technologies 1. Biodegradable materials At present, the main materials of orthopedic implants are metal (titanium, cobalt-chromium-molybdenum, stainless steel, etc.), PEEK, ceramics, polyethylene, etc. However, with the gradual maturity of orthopedic implants, especially for traumatic fractures, the homogeneity of traditional metal implants among enterprises is obvious, so enterprises need to seek breakthroughs to maintain their competitiveness. The development or use of new implant materials has become a consensus among enterprises. Degradable materials have broad application prospects because they can not only provide initial stability, but also be degraded and absorbed after fracture healing, avoiding secondary surgery. (1) Degradable metal material Degradable metal materials have good mechanical property, mainly including magnesium, iron, zinc and their alloys. The research of these materials is mainly focused on the internal fixation of traumatic fractures. Among them, magnesium alloy has good biocompatibility and its density is close to that of human bone, so it is the most widely studied. At present, the European Union has approved the world's first magnesium alloy degradable screw, but the degradation rate of magnesium metal is faster than the formation rate of new bone, and the degradation products are easy to accumulate around the tissue. Therefore, the degradation rate of magnesium alloys, the mechanism and process of corrosion degradation in vivo, and the products need to be further studied. The mechanical property and biocompatibility of zinc alloys are similar to those of magnesium, and the metal inertness makes the degradation rate of zinc alloys suitable. As an inorganic antibacterial material, zinc also has certain antibacterial properties, and it is one of the essential elements for human body, so zinc alloys are regarded as a new choice for degradable metal materials in the future. At present, zinc alloy has been successfully used in clinical cases of internal fixation of maxillofacial trauma fractures in China. However, the research of zinc alloy is still in its infancy, and a lot of research and clinical data are needed to support its safety and osteoinductive mechanism. (2) Absorbable polymer material Absorbable polymer materials can be decomposed into CO2 and H2O through a series of enzymes or chemical reactions in vivo, and do not produce additional elements in vivo, so they have no toxic effects on human body. Polylactic acid (PLA) is one of the most widely used absorbable polymer materials in the field of orthopaedics. It has good biocompatibility and has been widely used in spine, trauma, sports medicine and other fields. The original polylactic acid material has high brittleness, poor toughness and residual fragments after degradation, and after copolymerization with other monomers and process improvement, the extensibility of the material is increased on the basis of maintaining the strength of the material, the control of the degradation rate of the material to match with the regeneration rate of bone tissues can be realized, and the material can be completely degraded and absorbed. However, due to the poor mechanical property of polymer absorbable materials, the mature products on the market are mainly craniomaxillofacial and non-load-bearing bone fixations. With the upgrading of technology, there is a process of high-strength absorbable polymer materials for load-bearing parts, but to complete the transformation of products, a large number of performance and safety validation are needed, which is an important material in the field of orthopaedics and even biomedical engineering in the future. Bone graft materials account for more than 50% of biomaterial applications. At present, there are many kinds of bone graft materials on the market, and autogenous bone is the most recognized choice for bone graft. However, due to limited sources and greater trauma, clinical use is limited. In addition, allogeneic bone and xenogeneic bone also account for a certain proportion, and the largest share is artificial bone. Traditional artificial bones mainly include tricalcium phosphate, calcium sulfate, hydroxyapatite, etc. On this basis, bioactive glass has established its dominant position in the bone graft market by virtue of its good biocompatibility, osteogenic ability and degradability. With the increase of choices and the complication of diseases, the clinical requirements for products are also increasing. Therefore, on the basis of the existing bioglass, it has become the main direction of research to increase its toughness and plasticity and improve its osteogenic ability by adding collagen, hyaluronic acid and other materials. In a word, the application of absorbable polymer materials is a new trend of orthopaedic materials in the future and has broad application prospects. 2. Digital orthopaedics The Outline of the 14th Five-Year Plan mentions that in order to speed up the development of digitalization and build a digital China, digital technology has also been vigorously developed in the clinical application of orthopaedics in recent years. Digital orthopaedics covers surgery from preoperative planning to intraoperative navigation, as well as postoperative evaluation and rehabilitation, and the integration of these treatment processes forms a digital orthopaedic surgery platform. (1) Preoperative assistance Preoperative assistance includes doctor-patient remote communication and consultation, preoperative planning and other modules, and precise planning can be achieved through three-dimensional reconstruction model, simulation training, AR assistant diagnosis and other technologies. AR-assisted preoperative planning can change the tradition of analyzing a large number of flat medical image data before operation, import the image data into AR system, and realize the information presentation of image data through image segmentation and three-dimensional visualization technology. And the three-dimensional reconstruction model can provide more accurate anatomical parameters for a doctor, so that the doctor can more intuitively and comprehensively understand the situation faced by the operation; and because a three-dimensional image is closer to reality than plane data, the three-dimensional reconstruction model can effectively shorten the learning curve of the doctor. At the same time, through the virtual cutting function of three-dimensional model, doctors can repeatedly carry out simulation training and communication. (2) Surgical robot According to the open data of National Medical Products Administration, in 2020, domestic enterprises obtained 12 registration certificates for orthopaedic robots, including 3 navigation robots and the rest rehabilitation training robots. According to the statistics of Persistence Market Research, in 2018, the installed capacity of new orthopaedic robots in China was about 26, accounting for less than 4% of the global total, and by 2019, it had reached 138, accounting for about 12% of the global total of orthopaedic surgical robots. At present, there are more than 20 enterprises carrying out robot research in China, most of which are in the stage of prototype trial and clinical trial. Surgical robot navigation or assisted surgery can help doctors achieve accuracy, flexibility and minimally invasive operation, reduce radiation damage to doctors during operation, and shorten the recovery time of patients after operation. At present, the number of orthopaedic surgical robots in China is limited, the cost of surgery is high, and the medical insurance reimbursement policy is imperfect. Most of the leading international orthopedic enterprises enter the field of robotics through mergers and acquisitions to consolidate the existing orthopedic business. At the same time, in the future, robots may be integrated with the use of orthopedic consumables, and enterprises need to advance the layout to ensure that follow-up orthopedic products can maintain access to the use of surgical platforms. With the deepening of clinicians'understanding of robots and the support of policies for intelligent surgery, the clinical acceptance of surgical robots is further improving. From the perspective of health economics, robot-assisted surgery will have great social and economic benefits in the future. III. Market Development Trend and Forecast According to the "TheOrthopaedic Industry Annual Report 2020" report [5], in the global orthopaedic market in 2019, the United States ranked first with a share of $33.1 billion, accounting for 62%; Central Europe ranked second with a share of 24%; Of the 10% share in the Asia-Pacific region, China and Japan are the larger single markets; the rest account for 4%. In 2020, in the global orthopedic market, the joint market share is $16.1 billion, with a growth rate of -17.4%, including $7.6 billion for knee replacement, $6.4 billion for hip replacement, and $2 billion for limb joints; $7.9 billion for spine, with a growth rate of -18.1%, and $7.3 billion for trauma, with an increase rate of -15.4%; Sports medicine is 4.8 billion, with a growth rate of -17.3%. In the forecast of the global orthopedic market in 2021, joint replacement is $19.5 billion, with a growth rate of 21%, including $9.3 billion for knee joint, $7.8 billion for hip joint, and $2.4 billion for limb joint; $9.6 billion for spine, with a growth rate of 22%; $7.5 billion for trauma, with an increase of 19%; and $6 billion for sports medicine, with an increase of 23%. In order to cope with the problem of continuous expansion of orthopaedic patients caused by aging in China, through investigating the mode of foreign patients'visits, it is found that the number of day outpatient operations in the United States has exceeded 80% of the total number of operations, and in the past 10 years, the number of registered orthopaedic day outpatient clinics (including hospital outpatient clinics and independent surgical centers) has increased exponentially. In 2020, nearly 10000 operations were carried out in orthopaedic day clinics, most of the sports injury operations can be carried out in day clinics, and the number of joint replacement and spinal orthopedics operations in day clinics is also gradually increasing. Daytime outpatient service can reduce the average cost of hospitalization by 20% -40% and the cost of medicine by 37% -55%, alleviate the contradiction between supply and demand of medical resources, play an important role in optimizing medical resources and improving medical efficiency, and also have practical significance for the ongoing reform of medical supply side in China. At present, the popularization rate of day surgery in China is low, the payment and reimbursement policies are implemented according to outpatient regulations, and there is no matching medical insurance payment system. In addition, the nature of day surgery determines that patients leave the hospital without full recovery, so the outpatient department carrying out day surgery should ensure the safety and quality of the operation, do a good job of medical advice after discharge and prevent possible complications. It can be predicted that with the construction of medical information and the improvement of day outpatient facilities, orthopaedic day surgery in China will enter a rapid development stage, and the corresponding home care and rehabilitation service market will further develop. Therefore, the field of orthopaedic medical devices needs to further improve the medical system of "prevention, treatment and health" to play a role in graded diagnosis and treatment. References [1] Xu Shufu, General Manager of Zhengtian Business Department of Beijing Natong Technology Group Co., Ltd., undergraduate; Li Renyao, General Manager of Small Orthopaedics Business Department of Beijing Natong Technology Group Co.,nickel titanium wire, Ltd., graduate. [2] China Development Report 2020: Development Trends and Policies of China's Aging Population [3] Publicly available information on OECD official website [4] National Medical Products Administration public information [5] "TheOrthopaedic Industry Annual Report 2020" back to Sohu, see more Responsible Editor:. yunchtitanium.com
Originally published as There shouldn't be a single "lingerie model" like this! 01 Playing the edge ball of soft pornography with children, Who is doing evil? Eileen Chang's phrase "Be famous as early as possible" has recently been pushed to the forefront of the storm because of the chaos in the child model industry. A netizen posted an exposure of a children's underwear shop, questioning that the model pictures used on its sales page were playing the edge ball of soft pornography. From some of the product pictures displayed in the post, it is really uncomfortable for children to kneel on their buttocks, look back at their waists, tighten their private parts and take close-ups from above. Pictures of children's underwear shops exposed by netizens Expand the full text Most of the children's underwear on a certain treasure are not displayed by models. I didn't expect to get the response that "people with unhealthy thoughts see everything dirty". It was not until the post was finally moved to multiple platforms, triggering heated discussions, that the merchants began to replace the store pictures. A netizen who claimed to operate a children's wear brand also made a supplementary explanation, saying that the official has issued a notice requiring stores to "urgently investigate children's soft pornography". Netizens have not been able to breathe a sigh of relief at this point. Almost every year, the chaos of children's soft pornography, which makes onlookers angry, will be staged on various platforms for several rounds. Behind the increasingly rampant similar incidents, it is directed at an unfathomable grey industrial chain. But like the controversy over soft pornography in children's underwear stores, it is difficult to characterize it as a direct "money-goods transaction" in the past. Some netizens were even confused at the first time they saw these photos: "Are lingerie stores using edge ball gimmicks to disgust potential customers?" In January this year, a batch of children's soft pornographic expression packages appeared on a lifestyle APP. A large number of photos of Internet celebrity children were photoshopped with words such as "I am greedy for your body" and turned into "driving" emojis to be shared. Under this kind of post, most of them will attach the producer's WeChat. A reporter tried to add several accounts and found that the other party was either charging for divination or purchasing micro-businesses on behalf of others. The purpose of sharing emojis is mainly for drainage. There are many similar examples. Min Sijia, a media person, criticized the "pedophiles" on the short video platform in early January. The reason is that some netizens found that there are a large number of accounts on some short video platforms that use children to play pornographic edge ball. In such videos, boys and girls will expose their body parts to varying degrees, and even make some highly suggestive movements. The original video commented that his son only wore shorts to eat, and asked him to remove the bowl that blocked his crotch. The content of the comment section is even worse. It seems that this is just using the name of short videos to open the door for pedophiles. Strangely, however, some of these accounts do not appear to be commercial operations. Those accounts named after children are more like parents sharing their children's daily life. The original video shows the boy practicing "one word horse". Due to the development of e-commerce, live broadcasting and short video, more and more children have become potential "commodities". There is no clearly marked price, but it will still be displayed in front of the camera by parents. Faced with the influx of attention and praise, they may not have time to think about what kind of harm the comments and sexual innuendo will do to their children. In recent years, there has been a lot of controversy about child soft pornography. However, it is easy to confuse the public in the name of business under the cover of such identities as child models and Internet celebrities. Adults have really ignored the industrial chain of using children for profit for too long. 02 There is no right to refuse. There is no freedom of acceptance. For a long time, child models and little Internet celebrities have been synonymous with bright and beautiful in the eyes of ordinary people. In 2019, the child model Niu Niu was beaten, revealing the survival chaos of child models and little Internet celebrities. In the exposed video, Niu Niu's mother asked her 3-year-old daughter, "Can you cheer up?" As soon as the voice fell, he kicked his daughter again. This scene was evaluated by netizens at that time as "not educating children, but repairing cash machines". While the incident was hotly discussed by netizens, the child model industry behind it also caused a lot of discussion at that time. Children under the age of 10 can earn 30000 yuan a month or even 30000 yuan a day by shooting six or seven hours a day. The temptation of economic interests makes more and more parents "look forward to their children becoming stars". As a spectator, most ordinary people can only see the decent side of child models and little Internet celebrities. Few people reflect on when children who become "child laborers" to satisfy the desires of adults become tools. Google, the first child model in Zhili, has been interviewed by the media. At the age of 6, she has been able to say the official words "I must try my best to take a good picture so that all the customers are satisfied" when facing the camera. A person in charge of an advertising company explained in an interview that child models are generally precocious because they come into contact with many strangers during the shooting process. An observation program of Golden Eagle Cartoon once followed a child star, Xiao Xiangyu. She was only 6 years old when she took part in the show, but she was already an experienced drifter. In the program, the mother who used to be a journalist has been emphasizing that her daughter loves acting very much. He also said that at first his father and grandfather did not agree with the child to take this road, but later felt that she liked it from the bottom of her heart, and the whole family decided to support it. But later in the program, bra tape measure , Xiao Xiangyu confided her feelings to the camera. She said her goal was to become a superstar, and like the people who are famous now, there are many people who like her. It can also be seen from the continuous follow-up that the child has not yet formed a clear understanding of the performance and the identity of the actor, let alone love it. Maybe it was never acting that she was obsessed with. It's the Vanity Fair that my parents say that becoming a big star can be liked by many people. No one can tell whether parents are pushing their children into the industry out of a desire for material gain or simply because they think that high exposure and high returns are good for their children's future. Even some parents may just place their unrealized dreams on their children. But the confluence of various purposes has created a strange situation in which a family is now supported by children. In fact, many parents of little Internet celebrities have been questioned about using their children to circle money. A big family of cute baby emojis in China has been scolded for her mother's lying to win sympathy. In a live broadcast, the mother of the child said that her daughter's hand was pinched by a door when she was a child and had no money for treatment, so she fell ill. He also said that he was slowly saving money and would have an operation later, earning enough donations from netizens. As a result, it was revealed that the cute baby's finger was actually a congenital defect. In foreign countries, South Korean Internet celebrities Luo Xi, Quan Lv Er and Gavin, the "smirking boy", have caused some controversy because their parents have received too much business cooperation and their children have shown fatigue in activities. The so-called young fame, for these children, is it a halo or a shackle? 03 When children become adults The victim of "killing the goose that lays the golden eggs" While accusing parents of child models and Internet celebrities of using their children as money-making tools, concerns about their children's physical and mental health have also been widely discussed. When Luo Xi's parents broadcast live late at night, they forcibly woke up their daughter and greeted her fans, which attracted the opposition of netizens to "abuse children". Later, Quan Lv Er was arranged to eat by his mother, and the menu contained high-calorie food such as fried chicken hamburgers, which was considered to be "exchanging health for money". Worries about unbalanced nutrition and inadequate rest have been surrounding child models and little Internet celebrities. In Dongguan, 5-year-old child model Xiao Wei once fainted because of physical exhaustion. The @ GQ report revealed that in Zhili, the "hometown of Chinese children's wear", popular child models often shoot until 11 or 12 P. m., and can only do homework and rest between work. For these children, overwork is not uncommon, and hunger and exhaustion have become the norm. Such a life is hard to say healthy. In South Korea, the experience of child model Lee Eun-chae is even more disappointing. As her mother is a beauty blogger, Lee started skin care at the age of 4 and makeup at the age of 6. After her debut at the age of 6, she quickly attracted fans with her good appearance and delicate makeup. So her mother opened a channel for her to teach fans to make up and do their hair. The accident happened at the age of 12. The girl has barely grown since she was about 10 years old. Her parents took her to the hospital for examination and learned that her actual age was 12 years old, but her skeletal age had reached 16 years old. After further examination, it was found that because she used cosmetics too much and too early, the estrogen level in her body was too high, which led to precocious puberty. Four years of precocity and closed bones mean she has little room to grow taller. The Daily Mail reported that a British mother began injecting her child with Botox to remove tiny lines from her face from the age of 8 in order to win the beauty contest. Subconsciously, parents and even ordinary netizens have become accustomed to demanding these children by the standards of stars. Even gradually, they are trained and packaged into mature commodities in public opinion and work. Child models and little Internet celebrities bear too much pressure from the outside world, such as the expectations of parents, the abacus of training institutions, and the swords of the business world. When child star Arale's popularity soared with the reality show "Where Are We Going, Dad? 4", some crazy parents followed suit, saying that they wanted to train their children to be "the second Arale". After the broadcast of Where Are We Going, Dad? 4, Baidu Child Star Bar was once very active. According to Jiefang Daily, the 3-year-old chestnut was sent to a special training class for the same reason. Just one month after the training, the child had mental problems. Later, the doctor diagnosed Chestnut with depression. People around said that the chestnut mother cheated the child. The mother lost herself in the overwhelming advertisements of early education training, the doctrine of "being famous as early as possible" and the vanity of her parents. Whenever a similar controversy arises, there are always some people who will stand up and refute it, saying that children do not necessarily enjoy the feeling of being surrounded by cameras. On the short video platform, there are also some children of primary school age who secretly shoot videos to win the attention of the public. Those children who are highly expected by their parents are often good-looking and good at singing and dancing. It does seem reasonable that the spotlight is on them. But is there anyone who wants to be a big star at birth? It doesn't matter whether the kids want to be famous or not. The important thing is who sowed the seeds of fame and wealth in the hearts of these unworldly children. They are also forced to become puppets in the name of love. ↓ Vista Look at the World New Media Recruitment ↓ Thank you for reading here. We have prepared more exciting content for tomorrow. If you don't want to miss it, set Vista to see the world as a star. Vista "Look at the world", enter the homepage of the official account. Step 2: Click ".." in the upper right corner. 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Original title: 100 dynamic diagrams of mechanical principles, for collection and use! Principle of bearing friction Robotic arm Turbo gearbox Differential Expand the full text Ball tooth machine mechanism Take an old picture of mechanical preface, gear, beam plate, cam, slide rail.. Seemingly simple parts, skillfully combined by talented engineers,personalized tape measure, can accurately complete all kinds of complex work. The mechanical dynamic picture clearly expresses the mechanical action, principle and production process in a short animation way, which is fascinating. It can be called the most beautiful picture in the mechanical industry. Those who like robots often like it very much after seeing it! Radial engine of an aircraft Four-stroke engine Helicopt with single crankshaft and opposed piston engine Twin in-line eight-cylinder steam engine Cam Guide Mechanism Stirling engine Horizontally opposed engine Sewing machine Manipulator Slider mechanism Fixture Aircraft engine Crusher Cam type intermittent motion mechanism Belt drive Gear drive You like it? Xiaobian wants to hear your voice. Finally,tailor measure tape, a Gif that can be seen for minutes. More than 100 years ago, the automatic timing mechanism of the ancient self-ringing clock Don't underestimate the ball pen, the mechanical structure is absolutely not simple. Heart breaking to see this gear mechanism. Looking and pondering carefully, I found the mystery of this seemingly simple mechanism. Cam or gear? Can you tell the difference? Fully automatic small submachine gun loading, firing, retractable tape measure sewing ,bespoken tape measure, ejection mechanism, look at three minutes, to have a complete and continuous impression Is there any reference for the special reduction transmission mechanism? Middle School Students Build an Automated World with Lego Bricks Periodic sliding rail shifting fork mechanism, ingenious and commonly used mechanical structure This is how tiny metal chains are formed at high speed. The clearest and most complete loading, firing and ejection mechanism for automatic firearms (machine guns) Torsion spring swing mechanism, which is familiar and unfamiliar to engineers Continuous swinging and sliding mechanism This must be a manipulator made in Baoding, China. Baoding only plays with iron balls. It is not a legend that Lu Ban made his own flying birds and rode around Kyushu. Can you imagine the three-dimensional meshing and operation of the maddening special-shaped gear mechanism? Apart from showing off, this gear mechanism is really useless. The rotary engine invented by German Figas Wankel at the beginning of the last century Count how many cylinders and how many valves the engine is. The mechanical engineer gave his wife a ring, which could be turned a few times to calm down every time he quarreled furiously, and the result was.. It's even crazier Magnetic ooze engulfs small iron balls, as long as fine iron oxide powder is added to the ooze, it can be made into such a magical magnetic ooze with its own engulfing function. It's so quick that it hurts to look at my hand. So this is the ice cream cone. The unlocking process is like this. Locomotive principle Elevator door (originally the elevator door is opened and closed like this) The automatic production of rows of bullets. The processing of red glass bottles This is how the spiral macaroni is made. Clothes hanger one-step forming A Picture to Understand the Structure of an Electric Fan The magic of blending two liquids Amazing furniture Wood mimics water waves Working principle of radial engine The radial engine of an aircraft Sewing machine Naval Gun Ammunition Loading System Automobile constant velocity universal joint V-type engine-where the cylinders are arranged in two planes at an angle, the V6 engine In-line engine-its cylinders are arranged side by side in a row, L4 engine, which is used in ordinary cars. Horizontally opposed engine-The cylinders are arranged in opposite planes of the engine. The Porsche 911 has six cylinders of this type Maltese cross movement-used to control the movement of the second hand of the clock Stirling engine Principle of making iron chain How zippers work Pipe-free siphon principle Are you sure to enter the village quietly? It's a big brain hole. After the marriage of a lighter and a match. The hand confirmed that it would keep moving, and the thumb expressed dissatisfaction. Give you a mechanical drawing, how much do you know? My platform is committed to good article push, platform pictures and videos are from the network, does not represent the views of the platform and is not responsible for its authenticity,custom tape measure, for reference only. Thanks to the original creator, the copyright belongs to the original author. If infringement, please delete the platform message. Return to Sohu to see more Responsible Editor:. tape-measure.com
Original Title: [Technology] Discussion on Calculation of Perforated Aluminum Curtain Wall I. Application in Engineering Perforated aluminum sheet means a rectangular material of uniform thickness with a rectangular cross section obtained by press working (shearing or sawing) of pure aluminum or aluminum alloy material. Perforation rate, hole diameter, plate thickness and plate type are the key elements, among which perforation rate is the core factor affecting the unit of perforated aluminum plate, and it is the key design factor affecting the expression of visual integrity and reducing building energy consumption. Due to the influence of processing cost, unit weight, unit flatness and other factors, the thickness of perforated aluminum plate used as the outer skin is usually 1. 0 mm ~ 6.0 mm. Glass-Perforated Aluminum Double Curtain Wall Application Examples: Figure 1. Intelligent Manufacturing Technology Research Institute of Hefei University of Technology II. Discussion on Wind Pressure Value of Glass-Perforated Aluminum Curtain Wall Glass-perforated aluminum panel curtain wall, the outer skin is perforated aluminum panel, and the inner skin is glass panel; the outer skin directly bears the wind load However, due to the existence of holes, the wind can act on the inner skin through the holes, and the inner skin also bears the wind load. The values of the wind loads on the two skins are very complex. In practical engineering, the distributions of the external pressure on the outer skin, the internal pressure on the outer skin and the external pressure on the inner skin can be obtained through the simulation of wind tunnel tests, so as to obtain more accurate values of the wind loads on the outer and inner skins. When there is no wind tunnel test report, the author refers to some domestic and foreign wind load codes, double-layer curtain wall codes and related documents, hoping to get ideas and methods that can be used in practical engineering design. 1. Technical Code for Curtain Wall Engineering of Shanghai (DGJ 08-56-2012/J 12028-2012) Article 14.1.6 of Shanghai Code for Curtain Wall specifies the value of wind load for external ventilation double-layer curtain wall. The outer curtain wall bears all the wind load, and the inner curtain wall is reduced according to the ratio of cavity volume to effective ventilation area. By analogy with the glass-perforated curtain wall, it is assumed that the floor height is 3.6m, the curtain wall grid is 1.5m, the size of the middle cavity is 1.0m, and the perforation rate is 40%. The calculation V/Aen = 2.5m, which belongs to the range of 0 ~ 20m, and the proportion of the inner curtain wall bearing the wind is 100%, that is, all of them bear the wind. The wind load of the outer perforated aluminum plate is the same as that of the inner glass curtain wall, and the wind load value of the conventional curtain wall is taken. 2. Eurocode 1: Actions on structures-Part 1-4: General actions-Wind actions BS EN 1991-1-4: 2005 Clause 7.2.10 of the Eurocode specifies in detail the value of the wind pressure on more than one skin. By analogy with glass-perforated aluminum curtain wall, the outer skin is perforated and the inner skin is closed, and the total pressure coefficient of the outer layer is: positive pressure coefficient = 2/3 (conventional external pressure coefficient); negative pressure coefficient = 1/3 (conventional external pressure coefficient). Value of total pressure coefficient of inner layer : normal external pressure coefficient-normal internal pressure coefficient = normal total pressure coefficient. By analogy with the Chinese load code, the local shape coefficient of wind load is as follows: Expand the full text Curtain Wall Type/Area Large Area External Pressure Corner External Pressure Closed Internal Pressure Conventional curtain wall + 1.0-1.4 ± 0.2 Glass-perforated aluminum plate double-layer curtain wall outer layer 0.67-0.470 Inner + 1.0-1.4 ± 0.2 Note: The large face refers to the windward face, and the corner refers to the corner area of the face adjacent to the windward face. 3. Documents related to wind tunnel test The scale of the wind tunnel test model is generally 1:100. Due to the small aperture on the perforated aluminum plate, it is difficult for the wind tunnel test model to simulate the real situation of the perforated aluminum plate. After consulting the relevant literature,bra measuring tape, the conclusions of similar wind tunnel test reports are cited as a reference: (1) "Research on the Wind Load of the Envelope Structure of Changsha Meixi Lake International Culture and Art Center"-State Key Laboratory of Civil Engineering Disaster Prevention, Tongji University, the test model is a partial model, the scale ratio is 1:15, the outer layer of the double-layer curtain wall roof slab is GRC slab, the inner layer is a closed waterproof layer, and the distance between the two layers of skin is about 600 mm. There are 20mm and 50mm seams between the outer GRC plates along the vertical and horizontal directions. Conclusion of the test report: Based on the wind tunnel test results, it can be found that for the double-layer roof panel structure, the wind pressure on the inner surface of the outer layer and the wind pressure on the outer surface of the inner layer at the same position are basically the same, that is, the wind pressure in the cavity is basically the same. On the other hand, when the wind pressure on the outer surface of the outer curtain wall is a positive value,custom tailor tape, the wind pressure on the cavity at the corresponding position is also basically a positive value, but the pressure is reduced; similarly, (Suction), the wind pressure at the cavity at the corresponding position is also basically negative, and the absolute value of the pressure is also reduced. These results show that the pressure of the cavity part of the double-deck roof structure is basically related to the wind force on its outer surface, but the absolute value is reduced. Fig. 2 Photo of test model (2) Wind Load Characteristics and Gust Coefficient of Double-layer Curtain Wall of Rectangular Building-School of Civil Engineering and Architecture of Zhejiang University, the wind tunnel test project is Hangzhou Huanglong Comprehensive Office Building, the building plane is rectangular, the curtain wall type is external ventilation double-layer curtain wall, the scale ratio of the test model is 1:100, and holes are opened at the corresponding positions of the external curtain wall to simulate ventilation shutters. The results of the wind tunnel simulation are shown in the following table: The conclusion of the test is that for rectangular (L-shaped) corridor ventilation curtain wall, the wind load of the inner wall can be taken as the value of the single curtain wall, and it is safer; ? When it is located at the long side of the rectangle, it can be reduced appropriately according to the single curtain wall. When it is located at the corner and short side of the rectangle, it needs to be enlarged. (3) "Wind Pressure Distribution Test of Double-layer Curtain Wall of Typical High-rise Building"-School of Civil Engineering and Architecture of Zhejiang University, the wind tunnel test project is Lishui Electric Power Production and Dispatching Center of Zhejiang Province, the building plane is circular with small grooves, the curtain wall type is external ventilation double-layer curtain wall, the permeability rate is 7.2%, and the scale ratio of the test model is 1:150. Holes shall be drilled at corresponding positions on the outer curtain wall to simulate the ventilation louver. The results of the wind tunnel simulation are shown in the following figure: Test conclusion: For the arc-shaped corridor ventilation curtain wall, the wind load of the inner curtain wall can be taken as the value of the single curtain wall, which is safer; ? When it is located in the middle of the arc, it can be reduced appropriately according to the single curtain wall, and when it is located at the end of the arc, bespoken tape measure ,mini tape measure, it needs to be enlarged. Summary: The value of the local shape coefficient of the wind load on the inner and outer layers of the double-layer glass-perforated aluminum panel curtain wall is quite different from that of the single-layer curtain wall.The main influencing factors include the distribution of the double-layer curtain wall on the building surface, the opening of the aluminum panel, the distance between the inner and outer cavities, and the air circulation. When there is no wind tunnel test data in the actual engineering curtain wall design, the local shape coefficient of the curtain wall wind load can refer to the following values (mainly refer to the European standard and wind tunnel conclusions): the local shape coefficient of the outer perforated aluminum plate wind load is 0.67 in the large area, and 1.8 ~ 1.9 in the corner area; the local shape coefficients of the inner glass curtain wall wind load are taken according to the single-layer curtain wall 。 The inner and outer curtain wall panels bear the wind load directly, and the local shape coefficient is not reduced. The local shape coefficient of the supporting keel not directly bearing the wind is reduced according to the subordinate area, and the final calculated wind load value is not less than 1 kPa. III. Calculation and Analysis of Perforated Panel 1. Aluminum plate design of aluminum plate curtain wall In general, stiffeners are set on the back of the aluminum plate to divide the aluminum plate into small grids. The side ribs and middle ribs form constraints on the four sides of the grid plate. The aluminum plate grid is calculated according to the model of the four-side supporting plate. Take the aluminum single plate with a thickness of 2400 mm X 1200 mm and 3 mm as an example, the standard value of wind pressure is 1.5kPa, the stiffeners are arranged along the short side, and the spacing of stiffeners is 800 mm according to the calculation formula of metal plate in Technical Code for Metal and Stone Curtain Wall Engineering (JGJ 133-2001), which meets the requirements of strength and deflection. 2. The perforated aluminum plate has many holes on the plate, which weakens the rigidity of the panel, but at the same time, the wind bearing area of the panel is also reduced, both of which have an impact on the bearing capacity of the perforated plate. According to the actual engineering situation, the perforated aluminum plate is divided into two types: the first type is the plate with regular holes and spatial arrangement of stiffeners without affecting the appearance effect; the second type is the plate with irregular holes or not allowed to arrange stiffeners. The plates analyzed here are all large plates, and the plates with small size and narrow strips are not analyzed (they can be designed according to the conventional aluminum veneer). ① Perforated plate with stiffeners The calculation idea and method are based on the calculation of aluminum veneer, and the grid element and the corresponding edge support model are selected. The finite element method is used to analyze the aluminum plate without opening and the aluminum plate with two opening ratios. ANSYS model (1200x800 mm, 3mm thick, face element Shell163): Panel deformation cloud chart: Summary of calculation results: Aluminum Plate Type Maximum Deflection (mm) Ratio Unperforated aluminium plate 11.371.00 18.7% Perforation aluminum plate 12.68 1.12 32.5% Perforation rate Aluminum plate 13.291.17 It can be seen from the ratio of the results that the maximum deflection of the perforated aluminum plate is larger than that of the non-perforated aluminum plate, and the deflection will increase slightly with the increase of the perforation rate. Considering that the perforation rate is generally not too large in practical engineering (limited by the arrangement of holes), the utilization rate of the calculation results can be controlled below 85% by using the conventional aluminum plate calculation method, which can meet the needs of practical engineering design. ② Perforated plate without stiffener Because the plate is large and there is no stiffener, if we design and calculate according to the design idea of conventional aluminum plate, we can increase the thickness of the perforated plate to improve its stiffness to resist external load, but in actual engineering, the way of increasing the thickness will make the cost too high, which is not suitable for the needs of general engineering. In the standard, the constraint conditions of the folded edges around the metal plate are considered as simply supported edges, and the calculation formula is given according to the classical elastic mechanics plate and shell theory, which has certain limitations. If the constraint conditions of the folded edges around the plate are strengthened, not only the out-of-plane translation of the plate is constrained, but also the in-plane translation is constrained, that is, the displacement in the three directions of X/Y/Z is constrained. In this way, when the panel deforms under external load, the peripheral constraints will pull the panel, thus preventing the further increase of deformation. ANSYS model (1200x2400 mm, 3mm thick, face element): Panel stress and deformation nephogram: From the analysis results of stress and deformation nephogram, it can be seen that the maximum stress is around the holes in the middle of the perforated plate, and the stress distribution is mainly concentrated in the vertical holes parallel to the short side direction and the strip area between the holes. The maximum stress of the two kinds of perforated plates is 27 MPa, which meets the design value of bending strength of 3003-H24 aluminum alloy plate 100 MPa. The maximum deflection occurs in the middle of the panel, and the maximum deflection of the perforated plate is 9. 4 mm, which meets the requirements of the deformation limit. The maximum deformation calculation results are summarized as follows: Aluminum Plate Type 18.9% Perforation Aluminum Plate 33.8% Perforation Aluminum Plate Edge Constraint Case Constrained in Face Unconstrained in Face Constrained in Face Unconstrained in Face Maximum deflection (mm) 9.073 7.44 9.413 8.2 Check the side constraint counterforce. The counterforce of the long side in the in-plane direction is 34 kN, which is converted into a line load of 14.2k N/m. If the connecting bolts are arranged according to @ 200, a single bolt bears a standard shear value of about 3 kN, and the selection of M6 bolts or machine wires can meet the requirements. The lateral force will also have an adverse effect on the support keel in the long side direction. When the left and right grids of the keel are consistent, the adverse effects of the lateral force will offset each other. The keel with only one side grid at the edge needs to resist the load in the direction perpendicular to the panel ? Can also resist the lateral load action of parallel panels. The constraint of edge X/Y/Z can be realized through specific node practices (for reference): Note: The node in Scheme II is quoted from the perforated aluminum plate node on the outer layer of the frame open double-layer curtain wall of the BBVA Bank Project in Mexico. The building height of this project is 234.85 m, the outer panel is made of 3mm thick diamond perforated aluminum plate, the side length is 1.7 m, and the diagonal size is 2686 m2 100m. Fourth, the limitations and shortcomings of this paper. In the part of wind load value of glass-perforated aluminum panel double-skin facade, this paper lists the codes of various countries and the relevant literature and works in recent years, and gives the recommended value of local shape coefficient of wind load on the inner and outer layers of glass-perforated aluminum panel double-skin facade in practical engineering by means of induction, summary and analogy, but there is a lack of real theoretical derivation, actual test data and corresponding verification methods. In the part of the calculation and analysis of the perforated aluminum plate, by comparing the calculation methods and ideas of the standard formula, combined with the calculation results of the finite element analysis, this paper gives the calculation ideas and solutions of two forms of perforated aluminum plate with or without stiffeners. Some of the conclusions made in this paper only represent the author's own words, if there are more rigorous theoretical basis and ideas, as well as the corresponding experimental data, you are welcome to criticize and correct. References: [1] Load Code for the Design of Building Structures GB 50009-2012 [2] Technical Code for Metal and Stone Curtain Wall Engineering JGJ 133 [3] Technical Code for Double Curtain Wall Engineering QB/JH 102-2008 [4] Technical Code for Curtain Wall Engineering of Shanghai DGJ 08-56-2012/J 12028-2012 [5] Static Calculation Manual of Building Structures Compilation Group of Static Calculation Manual of Building Structures [6] 《Eurocode 1: Actions on structures-Part 1-4:General actions-Wind actions》BS EN1991-1-4:2005 [7] 《Minimum Design Loads for Buildings and Other Structures》ASCE/SEI 7-10 [8] Research on Wind Load of Envelope Structure of Changsha Meixi Lake International Culture and Art Center, State Key Laboratory of Civil Engineering Disaster Prevention, Tongji University [9] Wind Load Characteristics and Gust Coefficient of Double-layer Curtain Wall of Rectangular Building, School of Architecture and Engineering, Zhejiang University [10] Wind Pressure Distribution Test for Double-skin Curtain Wall of Typical High-rise Building, School of Architecture and Civil Engineering, Zhejiang University [11] Research on Simple Calculation of Uniformly Perforated Aluminum Plate under Uniformly Distributed Load, Beijing Jianghe,personalised tailor tape, Luo Zhengwu [12] Research on Design of Large Plate Perforated Aluminum Plate without Stiffener, Shenyang yuanda Hongxin; Shenyang Architectural Design Institute Wang Youqing Author: Yang Qing Liao Jie Wang Bin Source: Jianghe Chuangjian Group Co., Ltd. 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