Research On The Tensile And Tearing Properties Of Architectural Coated Fabric

Architectural coated fabric material is an important part of membrane structure and its mechanical properties are closely related to structural safety.On the one hand,the mechanical properties of Architectural coated fabric material are complex and uncertain.Hence,it is difficult to obtain the mechanical parameters easily and accurately.On the other hand,improper production and installation,aging of the membrane,piercing of sharp objects,etc.,often cause the material to fall into the initial defects.The stress concentration near the initial defects often causes the membrane to tear and break prematurely.In this paper,the tensile properties and tear properties of PTFE membranes and PVC membranes were studied.Firstly,by uniaxial tensile test,the tensile mechanical properties of two materials in different tensile directions were obtained,including the failure mechanism,breaking strength,elongation at break,elastic modulus.On this basis,the Tsai-Hill strength theory was used to predict the fracture strength.The elastic modulusstrain curve is used to analyze the variation law of the elastic modulus,and the integral mean value theorem is introduced to obtain the elastic modulus of the coated fabric materials.Secondly,by the center tearing tests,the tear properties of the two coated fabric materials were obtained,including the tearing damage process,the failure mode,and the tear strength.On this basis,the residual strength is introduced to characterize the ultimate load carrying capacity of the coated fabric materials under initial defects.Investigate the factors affecting the residual strength of architectural fabrics,including loading rate,slit size,slit angle,size effect,membrane strength grade,braided structure,etc.At the same time,PTFE coated fabrics PVC coated fabrics adopt different fabric and surface layer materials,and hence,the similarities and differences of tensile properties and tear properties are analyzed.Finally,two residual strength prediction theories are used: fracture mechanics theory and stress field theory to predict the residual strength of coated fabrics under initial defects.The residual strength prediction formula of PTFE coated fabrics PVC coated fabrics were constructed respectively.On this basis,according to the maximum stress on the membrane surface in the structure,the maximum allowable slit length of coated fabric materials is obtained,which provides a basis for the safety evaluation of the structure.