膜結(jié)構(gòu)-天津大學(xué)（96頁）

1、MembraneStructureChapter 6 第六章MembraneStructure膜結(jié)構(gòu)6.1 Development and Characteristics膜結(jié)構(gòu)的發(fā)展與特點(diǎn) What is membrane structure？膜結(jié)構(gòu)是指采用多種高強(qiáng)薄膜材料及輔助結(jié)構(gòu)通過一定方式使其內(nèi)部產(chǎn)生一定的預(yù)張力，并形成預(yù)應(yīng)力控制下的某種空間形態(tài)，具有足夠剛度以抵抗外部荷載作用的一種空間形式。包括了充氣膜結(jié)構(gòu)、張拉膜結(jié)構(gòu)和索膜結(jié)構(gòu)。According to mechanical characteristics：Inflatable Membrane Structure 充氣式膜結(jié)構(gòu)Ten

2、sile Membrane Structure 張拉式膜結(jié)構(gòu)Skeleton Type Membrane Structure 骨架式膜結(jié)構(gòu)Membrane structure is a new kind of spatial structure, in which many kinds of high-strength membrane materials as well as assistant structures are used to produce some prestress, and certain spatial shapes are formed under the cont

3、rol of the prestress that have sufficient stiffness to carry the external loads. MembraneStructure Air-supported Membrane Structure 氣承式膜結(jié)構(gòu)Inflatable Membrane Structure 充氣式膜結(jié)構(gòu) Air-inflated Membrane Structure 氣脹式膜結(jié)構(gòu) 氣脹式膜結(jié)構(gòu)是指如同氣球一般，將膜材包裹成封閉構(gòu)件，向膜構(gòu)件內(nèi)部充氣，使膜材產(chǎn)生張力，從而具有一定剛度，將多個(gè)膜構(gòu)件組合形成整體受力體系。 氣承式膜結(jié)構(gòu)是指通過氣壓控制系統(tǒng)

4、向建筑物室內(nèi)充氣，保持室內(nèi)外一定的氣壓差，從而使膜材產(chǎn)生預(yù)張力，以保證結(jié)構(gòu)剛度。 The air-supported membrane structure uses pressure control system to inflate the buildings to keep a certain degree of draught head inside as well as outside of the structure, and then prestresses appear in the membrane materials which ensure the stiffness of

5、 the structure. The air-inflated membrane structure is just like a balloon formed by wrapping the membrane materials into a closed component , inflating the component to make the membrane materials prestressed as well as have enough stiffness and finally combing the membrane members. MembraneStructu

6、re Development of Inflatable Membrane Structure 充氣式膜結(jié)構(gòu)的發(fā)展Willian Lancheste, British, put forward the first inflatable tent in 1971. 早在1917年，英國人W蘭徹斯特（WillianLanchester）首次提出了氣承式帳篷。After World War 2, the United States began to use the membrane structure as the military facilities construction. 第二次世界大戰(zhàn)后

7、，美國實(shí)現(xiàn)了以膜結(jié)構(gòu)作為軍用設(shè)施的建造形式。Walter Bird, American, built the first modern inflatable membrane structure, Doppler Radar Dome, in 1946. 1946年，美國人W勃德（Walter Bird）建成了第一個(gè)現(xiàn)代充氣膜結(jié)構(gòu)，多普勒雷達(dá)穹頂。 雷達(dá)防護(hù)罩 Doppler Radar DomeMembraneStructureIn 1967, the first international inflatable structure conference was held in the Ge

8、rman Stuttgart, which promoted the development of the inflatable structure. 1967年，第一屆國際充氣結(jié)構(gòu)會議在德國斯圖加特召開，促進(jìn)了充氣結(jié)構(gòu)的發(fā)展。In 1970, the World Expo in Osaka, Japan, David Geiger designed the United States Pavilion. 1970年，日本大阪世博會上，由D蓋格設(shè)計(jì)的美國館。Fuji Museum was designed by Mamoru Kawaguchi as a sausage inflatable

9、membrane structure. 世博會上，川口衛(wèi)設(shè)計(jì)的香腸氣脹式膜結(jié)構(gòu)日本富士館同樣引人注目。 Development of Inflatable Membrane Structure 充氣式膜結(jié)構(gòu)的發(fā)展日本大阪博覽會富士館Fuji Museum日本大阪博覽會美國館The United States PavilionMembraneStructureMichigan, the Pontiac “Silver Domein 1975.1975年建成的密歇根州龐蒂亞克“銀色穹頂”, 平面為220m168m橢圓形。 Active Center of University of Califor

10、nia, USA, in1976.1976年建成的美國加利福尼亞州圣克拉勒大學(xué)活動中心,平面為90.5m59.4m橢圓形。密歇根州龐蒂亞克銀色穹頂The Pontiac “Silver Dome加利福尼亞州圣克拉勒大學(xué)活動中心Active Center of University of California, USA Development of Inflatable Membrane Structure 充氣式膜結(jié)構(gòu)的發(fā)展MembraneStructureFangshan Beijing swimming pool and Anshan Nongwei natatorium were fir

11、st applications of membrane structure in China. 1995年建成的北京房山游泳館和鞍山農(nóng)委游泳館是我國第一次正式應(yīng)用于工程的氣承式膜結(jié)構(gòu)，標(biāo)志著我國內(nèi)地膜結(jié)構(gòu)工程發(fā)展的興起。 Development of Inflatable Membrane Structure 充氣式膜結(jié)構(gòu)的發(fā)展Indoor golf training field in Beijing Tongzhou starlake. 北京通州星湖園法利室內(nèi)高爾夫練習(xí)場Broadwell tennis hall in Beijing Chaoyang Park. 北京朝陽公園的博德維網(wǎng)球館

12、MembraneStructureTensile Membrane Structure 張拉式膜結(jié)構(gòu)Skeleton Type Membrane Structure 骨架式膜結(jié)構(gòu) The skeleton type membrane structure is formed by covering the steel truss system or grid structure with membrane materials. Similar to the common structures, the membrane materials are used as the retaining st

13、ructures while the skeleton is the load-bearing system in the skeleton type membrane structure . This kind of structure has been widely recognized and applied to the long-span stadium, exhibition center and so on.The membrane material only plays a roleas envelope and the frame can form an independen

14、t force system. The skeleton type membrane structure is widely used in the stadium, exhibition center, transportation hub etc. 骨架式膜結(jié)構(gòu)是在一般的鋼桁架體系或網(wǎng)架結(jié)構(gòu)等骨架上覆蓋膜材，與常規(guī)結(jié)構(gòu)相似，膜材僅僅起到圍護(hù)結(jié)構(gòu)的作用，骨架可獨(dú)立形成受力體系，易于被工程界理解和接受，并廣泛使用于大型體育場館、展覽中心、交通樞紐等。 Tensile membrane structureoriginates from cable net structure and is for

15、med by prestressing the structure in certain ways to make it have certain shapes as well as stiffness. In the tensile membrane structure, the roof and its supporting structure constitute the load-bearing system.張拉膜結(jié)構(gòu)由索網(wǎng)結(jié)構(gòu)發(fā)展而來，通過一定的方式給膜體施加一定的預(yù)張力，使其具有一定的形狀和剛度，膜結(jié)構(gòu)的曲面單元與其支承體共同構(gòu)成了一個(gè)完整的結(jié)構(gòu)受力體系。MembraneStru

16、ctureDevelopment of Tensile Membrane Structure 張拉式膜結(jié)構(gòu)的發(fā)展The tent built in Kassel Gardening Exhibition Design by the German scholar FreiOtto in 1955 is the earliest modern membrane structurein the word. 德國學(xué)者F奧托在Kassel園藝展設(shè)計(jì)建成的帳篷成為最早的現(xiàn)代張拉膜結(jié)構(gòu)。The German Pavilion at the Montreal International Fair was de

17、signed by German scholar FreiOtto in 1967, which is considered to be the first real sense of tensile membrane structure. 德國學(xué)者F奧托在加拿大蒙特利爾國際博覽會上設(shè)計(jì)的德國館，被認(rèn)為是第一座真正意義上的張拉式膜結(jié)構(gòu)建筑。加拿大蒙特利爾國際博覽會德國館The German Pavilion at the Montreal International FairMembraneStructureThe development of PTFE has greatly promote

18、d the application of tension membrane structure. For example, the United States of California LaVine College Student Activity Center is the first membrane structure with PTFE built in 1973. 1973年建成的美國加利福尼亞拉維恩學(xué)院學(xué)生活動中心是用PTFE膜材建造的第一個(gè)膜結(jié)構(gòu)。Jeddah International Airport built in 1981 is currently the larges

19、t tensile membrane structure. 1981年建成的沙特阿拉伯吉達(dá)國際航空港是目前規(guī)模較大的張拉膜結(jié)構(gòu)。Development of Tensile Membrane Structure 張拉式膜結(jié)構(gòu)的發(fā)展美國加利福尼亞拉維恩學(xué)院學(xué)生活動中心LaVine College Student Activity Center沙特阿拉伯吉達(dá)國際航空港Jeddah International AirportMembraneStructureDevelopment of Tensile Membrane Structure 骨架式膜結(jié)構(gòu)的發(fā)展The Shanghai Stadium

20、built In 1997 for the Eighth National Games is the first application of membrane structures in large permanent building in China. 1997年為第八屆全運(yùn)會興建的上海八萬人體育場是我國首次將膜結(jié)構(gòu)應(yīng)用于大型永久性建筑。Shanghai Hongkou football Stadium adopted the membrane structure of the cable truss supported on the saddle shaped large cantil

21、ever. 1999年建成的上海虹口足球場采用了鞍形大懸挑空間索桁架支承的膜結(jié)構(gòu)。上海八萬人體育場The Shanghai Stadium上海虹口足球場Shanghai Hongkou football StadiumMembraneStructureIn 2008 Beijing Olympic Games, the new ETFE materials were used in The National Stadium “Birds Nest and The National Swimming Center Water Cube . 2008年北京奧運(yùn)會，國家體育場“鳥巢”(圖6.1.13

22、)和國家游泳中心“水立方” 均采用了ETFE這種新材料，分別是國內(nèi)首次應(yīng)用ETFE單層膜材和ETFE氣枕的工程。Development of Tensile Membrane Structure 骨架式膜結(jié)構(gòu)的發(fā)展國家體育場“鳥巢”The National Stadium “Birds Nest國家游泳中心“水立方”The National Swimming Center Water Cube .MembraneStructureThe Central Corridor of The Guangzhou South Railway Station. 廣州南站中央通廊位于站房的中部，采光屋面系統(tǒng)

23、由1182個(gè)菱形的氣枕組成。Dalian Sports Center Stadium. The plane is oval. 大連體育中心體育場是第十二屆全國運(yùn)動會的主要比賽場館之一，整體平面為橢圓形。Tianjin YuJiabao Station Dome. The main part of the structure is covered by three layer ETFE cushion. 天津于家堡站房穹頂為京津城際鐵路的延伸線，主要部分采用了三層ETFE氣枕覆蓋。Development of Tensile Membrane Structure 骨架式膜結(jié)構(gòu)的發(fā)展廣州南站中央通

24、廊The Central Corridor of The Guangzhou South Railway Station 大連體育中心體育場Dalian Sports Center Stadium天津于家堡站房穹頂Tianjin YuJiabao Station DomeMembraneStructure6.1.2 Characteristics of Membrane Structure 膜結(jié)構(gòu)的特點(diǎn)Light weight, long span. 自重輕，跨度大Various architectural appearances. 建筑造型豐富Convenient construction.

25、 施工方便Cost savings 經(jīng)濟(jì)性High safety 安全性Good light transmission 透光性Strong ability of self cleaning 自潔性 AdvantagesMembraneStructureThere are also some disadvantages of the membrane structure, mainly in the following aspects:Short service life. The service life of membrane material is generally 35 to 15 y

26、ears. 膜材的使用壽命一般為1535年，雖然有些采用玻璃纖維膜材的實(shí)際工程使用超過25年仍保持良好性能，但與傳統(tǒng)的混凝土或鋼材相比仍有相當(dāng)差距，與通?！鞍倌甏笥?jì)”的設(shè)計(jì)理念不符。The ability to resist the local load is weak. 膜結(jié)構(gòu)抵抗局部荷載作用的能力較弱，屋面在局部荷載作用下會形成局部凹陷，造成雨水和雪的淤積，即產(chǎn)生所謂的“袋狀效應(yīng)”，嚴(yán)重時(shí)可導(dǎo)致膜材的撕裂破壞。Maintenance cost is high in the process of the use of inflatable membrane structure. 充氣膜結(jié)構(gòu)使

27、用過程中的維護(hù)費(fèi)用較高，需要充氣系統(tǒng)和控制系統(tǒng)時(shí)刻運(yùn)轉(zhuǎn)維持。Constructors need professional training and the technology is difficult to master. 由于膜結(jié)構(gòu)屬于新型結(jié)構(gòu)形式，設(shè)計(jì)與施工一般需要專門的膜結(jié)構(gòu)公司完成，施工人員需要專業(yè)培訓(xùn)并持證上崗，技術(shù)難度較大。6.1.2 Characteristics of Membrane Structure 膜結(jié)構(gòu)的特點(diǎn)MembraneStructure6.2.1 Development of Membrane Materials 膜材的發(fā)展ETFE是乙烯-四氟乙烯共聚物，具有

28、高透光率，最高可達(dá)96%，有良好的抗老化性、耐火性、自潔性等優(yōu)良性能，易加工。Surface CoatingFiber BaseC film聚氯乙烯 polyvinyl chloride (PVC) 聚酯纖維 polyester fiberB film聚乙烯基類 polyethylene玻璃纖維 glass fiberA film聚四氟乙烯 （PTFE）玻璃纖維 glass fiber Ethylene tetrafluoroethylene(ETFE) is a fluorine-basedplastic. It has high light transmission ratio which

29、 can reach 96%, favorable anti-aging, anti-fire, self-cleaning properties, it is easy to process as well.6.2 Development, Types and Basic Properties of Membrane Materials 建筑膜材的發(fā)展、類型和基本性能MembraneStructure（一） Fabric Membrane Material 織物類膜材A kind of composite material with high strength and good flexib

30、ility. It mainly includes base material, coating, surface coating, adhesive and so on.一種具有高強(qiáng)度、柔韌性好的復(fù)合材料。主要包括基層材料、涂層、表面涂層以及膠黏劑等。6.2.2 Types of Membrane Materials 膜材的類型某種織物類膜材A fabric membrane material織物類膜材的一般構(gòu)造圖The general structure diagram of fabric membrane materialMembraneStructure1. Base Material

31、 基層材料（一） Fabric Membrane Material 織物類膜材 The base material is composed of all kinds of fabric fibers which determine structural and mechanical properties of the material.There are different kinds of base materials such as carbon fiber, Kevlar (Fang Guan) fiber, polyester fiber, glass fiber and so on.

32、 According to the requirement of the strength of the structure, polyester fiber and glass fiber are usually selected as building membrane materials. 基層材料由各種織物纖維編織而成，決定材料的結(jié)構(gòu)力學(xué)特性?；鶎硬牧系钠贩N較多,碳纖維、Kevlar(芳綸)纖維、聚酯纖維、玻璃纖維等。根據(jù)建筑結(jié)構(gòu)使用強(qiáng)度的要求, 建筑膜材一般選用聚酯纖維和玻璃纖維。2. Coating 涂層 At present, various resin coating mate

33、rials are available.Such as PVC (聚氯乙烯), PTFE (聚四氟乙烯, 商品名Teflon), Silicone (硅酮) and Flexurane（聚氨酯）. The first three coating materials are usually used in buildings.其中前三者為建筑常用涂層材料。MembraneStructureBase MaterialPolyester Fiber Glass Fiber Advantages High tensile strength抗拉強(qiáng)度高Good elasticity彈性好Elongatio

34、n在拉伸屈服前有較大的伸長變形能力High elastic modulus彈性模量較高High strength強(qiáng)度較高Small creep徐變小Not easy to aging不易老化ShortcomingsCreep and wrinkle 在拉力和紫外線的長期作用下會有較大的徐變, 容易造成膜面褶皺Small elastic deformation彈性變形小Brittle materials脆性破壞材料wet and hot environment have influenceon mechanical property力學(xué)性能受濕、熱環(huán)境影響較大MembraneStructureC

35、oating PVC (聚氯乙烯)PTFE (聚四氟乙烯)Silicone (硅酮)Advantages Flexible performance柔韌性能較好Flexible可卷折Anti ultraviolet ability抗紫外線能力強(qiáng)Light transmission透光性Self cleaning自潔性好 Not easy to aging不易老化Long Life壽命長 Weldability可焊性Good flexibility柔韌性好Good transparency透光性好Good waterproof防水性好Easy construction施工方便Shortcoming

36、sChemical changesunder light 光照下易發(fā)生化學(xué)變化Big Stiffness剛度較大Folding reduces its strength運(yùn)輸施工中的卷折使其強(qiáng)度降低Micro cracks微細(xì)裂縫,使水分侵蝕基層纖維，降低使用壽命和強(qiáng)度Self cleaning is worse than PTFE自潔性比PTFE差Bad weldability可焊性不良Mosaic is difficult拼接較困難ImprovementAdd PVDF or PVF outside the PVC 在PVC涂層外涂敷PVDF,PVF等Add silicone between

37、 the base layer and surface layer of PTFE.在基層和PTFE面層間加涂硅酮防水層。MembraneStructure3. Fabric membrane material that are usually used 常用的織物類膜材TypeMaterial AdvantagesShortcomingsPVCCompounded by PVC coating and polyester fiber base PVC涂層和聚酯纖維基層復(fù)合Wide application應(yīng)用廣泛Inexpensive價(jià)格低廉Resistance to aging耐老化性Sel

38、f cleaning自潔性PVC with surface materialSurface material is PVDF or PVF表面涂層聚偏氟乙烯或聚氟乙烯Resistance to aging耐老化性Self cleaning自潔性PTFECompounded by PTFE coating and glass fiber base聚四氟乙烯涂層和玻璃纖維基層復(fù)合High tensile strength抗拉強(qiáng)度高Resistance to aging耐老化性Self cleaning自潔性Expensive價(jià)格較高（一） Fabric Membrane Material 織物類膜

39、材MembraneStructure（二）Non fabric membrane material 非織物類膜材 Compared to fabric membrane material, non-fabric membrane material is formed by thermal plastic with no base cloth. This material is isotropic and its tensile strength is relatively low. 與織物類膜材相比，非織物類膜材由熱塑成形，沒有基布，薄膜張拉各向同性，抗拉強(qiáng)度相對較低。圖6.2.2 ETFE膜

40、材MembraneStructureETFE(Ethylene Tetra Fluro Ethylene)The light transmittance 透光率 Tensile strength 抗拉強(qiáng)度Aging resistance 抗老化性 Good self-cleaning 自潔性良好Non flammable 不易燃In 2008 Beijing Olympic Games, the main stadium “Birds Nest and the National Swimming Center Water Cube adopted the ETFE membrane as bu

41、ilding materials for the first time.Since then, the ETFE film began to develop rapidly in China and waswidely used.（二）Non-fabric membrane material 非織物類膜材2008年北京奧運(yùn)會主場館鳥巢和國家游泳中心水立方是國內(nèi)首次采用ETFE膜作為圍護(hù)材料的工程，向人們展示了ETFE膜材的無窮魅力。此后，ETFE膜在國內(nèi)開始迅速發(fā)展，得到廣泛應(yīng)用。MembraneStructure6.2.3 Basic Properties of Membrane Mater

42、ials 膜材的基本性能（一） Basic Properties of fabric membrane material 織物類膜材的基本性能1. Basic parameters基本技術(shù)參數(shù)Substrateweight（基材重量）： Expressed by fiber number and weight per area, generally bigger than 100g/. 以纖維纖度表示，同時(shí)以單位面積重量表征，一般大于100g/ ；Thickness of membrane materials（膜材厚度）： The distance between substrate coat

43、ing and fiber surface is generally 0.31.2mm . 基材纖維與涂層表面的距離，常在0.31.2mm之間；Thickness of coatings （涂層厚度）： The distance between top surface and coating surface is generally 0.31.2mm . 纖維頂面與涂層表面的距離，常為0.10.3mm；Fiber weave（纖維織法）： Textile patternsof fiber include plain weaving, basket weaving and so on. Diff

44、erent weaving methods affect the mechanical properties of membrane materials.纖維的紡織方式，如平織、籃式編織等，不同的織造方法影響著膜的力學(xué)性能；Breadth（幅寬）： Width of membrane sheet is generally 5004500mm. 膜材卷材的寬度，常在5004500mm。MembraneStructureThe mechanical properties of fabric membrane mainly depend on the fiber fabric. 織物類膜材的力學(xué)性能

45、主要取決于纖維基布。The tensile strength of membrane material is high, but the compressive stiffness and bending stiffness is almost zero. 膜材具有較高的抗拉強(qiáng)度，但抗壓剛度和抗彎剛度幾乎為零。（2）Durability and Self-cleaning耐久性與自潔性The Membrane Material 膜材Durability and Self-cleaning耐久性和自潔性Service Life使用年限PTFEGood 較好More than 25 years 2

46、5年以上PVCNot good 不太理想Add PVF or PVDF coating can effectively improve the self-cleaning property.附加涂層PVF或PVDF，有效地改善其自潔性。More than 1015 years 1015年以上（1） The Mechanical Properties 力學(xué)性能MembraneStructure The elastic modulus of the membrane material is low which is beneficial to form the complicated shapes

47、 of the structure. However, creep and relaxation will occur after the membrane material is pretentioned. 膜材的彈性模量較低，有利于膜材形成復(fù)雜的曲面造型。但膜材在張拉成形后的一段時(shí)間內(nèi)，會產(chǎn)生徐變和松弛。 Membrane materials have excellent flame retardant and high temperature resistant performance. Generally speaking, PTFE membrane material is non

48、combustible material and PVC material is flame retardant material. 具有卓越的阻燃和耐高溫性能。一般情況下認(rèn)為PTFE膜材是不可燃材料，PVC材料是阻燃材料。（一） Basic Properties of fabric membrane material 織物類膜材的基本性能（3）Elastic modulus 彈性模量（4） Fire Resistance 防火性能MembraneStructure（5） Good Acoustic Performance 良好的聲學(xué)性能（一） Basic Properties of fabr

49、ic membrane material 織物類膜材的基本性能 Fabric membrane material is a composite material. A lot of experiments show that, the membrane material has strong nonlinear and viscoelastic properties. However, in the actual stress range, the membrane material is still assumed as linear elastic in structure. 織物類膜材是

50、復(fù)合材料，由大量的實(shí)驗(yàn)表明，膜材具有很強(qiáng)的非線性和粘彈性。但是，目前在做膜結(jié)構(gòu)的結(jié)構(gòu)分析時(shí)，在膜材的實(shí)際應(yīng)力范圍內(nèi)，仍假定膜材為線彈性體。（6） Linear Elastic 線彈性體假定 MembraneStructure The deformation of membrane is large, and the strain is small. 由于膜材變形大，而應(yīng)變小，因而在膜結(jié)構(gòu)分析中假定膜材保持正交異性且方向不變。 The determining factors of permissible stress in design of membrane structure include

51、 the structure safety coefficient and reduction coefficient. 膜結(jié)構(gòu)設(shè)計(jì)中膜內(nèi)允許應(yīng)力的確定因素有:結(jié)構(gòu)安全系數(shù)和折減系數(shù)。（一） Basic Properties of fabric membrane material 織物類膜材的基本性能MembraneStructure（二） Basic Properties of non fabric membrane material 非織物類膜材的基本性能Strong and durable 厚度通常為50300m，非常堅(jiān)固、耐用；Tensile strength 單層膜抗拉強(qiáng)度在35MP

52、a以上，斷裂延伸率大于350%；High light transmittance 具有高透光率，透光率在50%96%之間,可以通過調(diào)節(jié)表面印點(diǎn)覆蓋率和材料厚度來調(diào)節(jié)光強(qiáng)度和紫外線的透過率；Self cleaning 張拉后的膜面極為光滑且有自潔能力；Service life 平均使用壽命30年左右；Nonflammable ETFE膜材不易燃, 且在燃燒融化后會自行熄滅, 達(dá)到B1、DIN4102防火等級標(biāo)準(zhǔn)。ETFE(Ethylene Tetra Fluro Ethylene) 乙烯-四氟乙烯共聚物MembraneStructure1. The tensile test at room te

53、mperature 常溫下單向拉伸試驗(yàn)兩個(gè)屈服點(diǎn)，可采用三折線簡化模型。第一屈服應(yīng)力平均值為13.915.8MPa，第一屈服應(yīng)變平均值為2.1%2.3%，第二屈服應(yīng)力平均值為21.022.2MPa，第二屈服應(yīng)變平均值為14.4%15.4%，彈性模量建議按割線彈性模量取650MPa。（二） Basic Properties of non fabric membrane material 非織物類膜材的基本性能Two yield points. The model can be simplified by using the three line.The first average value o

54、f the yield stress is 13.9 15.8MPa,The first average value of the yield strain is 2.1%2.3% ,The second average value of the yield stress is 21.022.2MPa ,The second average value of the yield strain is 14.4%15.4% ,According to the recommendations of secant elastic modulus,the elastic modulus is 650MP

55、a. MembraneStructure2. The tensile test at low temperature 低溫下單向拉伸試驗(yàn) 隨著溫度的降低，ETFE薄膜應(yīng)力-應(yīng)變曲線在強(qiáng)化前幾乎變成連續(xù)的曲線。與常溫相比低溫下ETFE薄膜的抗拉強(qiáng)度有較大提高，而延性則明顯降低。 ETFE薄膜割線模量變化幅度在10以內(nèi)，可忽略低溫對其影響。ETFE薄膜低溫單向拉伸應(yīng)力應(yīng)變曲線The ETFE thin film stress - strain curve on the tensile test at low temperature（二） Basic Properties of non fabric

56、 membrane material 非織物類膜材的基本性能 With the decrease of temperature, stress - strain curve of the ETFE almost turned into a continuous curve before strengthening. Compared with under normal temperature, the tensile strength of ETFE films under low temperature is greatly improved, and the ductility is si

57、gnificantly reduced.However, the effect of low temperature on ETFE film can be ignored when its secant modulus variation is less than 10%.MembraneStructure3. Cyclic tensile tests at room temperature 常溫下循環(huán)拉伸試驗(yàn)Elastic stage（彈性階段）： No obvious residual strain; Good elastic properties ; Design according

58、to the assumption of elastic material.無明顯的殘余應(yīng)變，呈較好的彈性性能，設(shè)計(jì)時(shí)可按材料彈性假定進(jìn)行。Yield stage（屈服階段）： The phenomenon of stress relaxation happens; Large residual deformation after unloading; Enlarged the elastic limit; Stress hardening phenomenon happens;薄膜出現(xiàn)應(yīng)力松弛現(xiàn)象，卸載后將產(chǎn)生很大的殘余變形，彈性極限提高, 出現(xiàn)了應(yīng)力硬化現(xiàn)象，設(shè)計(jì)時(shí)應(yīng)充分考慮。 ETFE

59、material with long time stretching will produce significant creep. Its size is related to the tensile stress and temperature. ETFE 薄膜受到長時(shí)間拉伸時(shí)會產(chǎn)生較為顯著的徐變, 其大小與拉伸應(yīng)力、溫度密切相關(guān)。（二） Basic Properties of non fabric membrane material 非織物類膜材的基本性能MembraneStructure6.3 The form of membrane structure 膜結(jié)構(gòu)的形式 6.3.1 Cl

60、assification of membrane structure 膜結(jié)構(gòu)的分類 常用的一種分類方法是將膜結(jié)構(gòu)分為充氣式膜結(jié)構(gòu)、張拉式膜結(jié)構(gòu)、骨架式膜結(jié)構(gòu)。Inflatable Membrane Structure充氣式膜結(jié)構(gòu)Tensile Membrane Structure張拉式膜結(jié)構(gòu)Skeleton Type Membrane Structure骨架式膜結(jié)構(gòu)MembraneStructure6.3.2 The selection of membrane structure 膜結(jié)構(gòu)的選型 膜結(jié)構(gòu)的設(shè)計(jì)核心Inflatable Membrane Structure(充氣式膜結(jié)構(gòu)): The