Research On Tensile Mechanical Properties Of Damaged Membranes

In this paper,the mechanical properties of building membrane material PTFE are the main research content,the damage(crack and hole)PTFE membrane material is the main research object,and the experimental research and numerical simulation are the main research methods.The global strain field,displacement field,ultimate strain at the damage,ultimate bearing capacity and fracture of membrane material in uniaxial and biaxial tensile process are analyzed and compared Elongation,strain concentration factor,modulus of elasticity and Poisson's ratio,etc.In the experiment,digital image correlation DIC is used,and the large-scale modeling software ABAQUS is used to simulate the microstructure of PTFE membrane material.The research contents and results are as follows:(1)Designing the uniaxial tensile test of all kinds of damaged membrane materials,to obtain the three-stage properties from tensile to complete fracture,and to analyze the influence of different diameter,different location,different number of holes on the PTFE membrane materials,as well as different length,different location and direction,different number of cracks on the tensile fracture mechanical properties of the membrane materials.(2)Through uniaxial biaxial tensile test,the distribution law of strain field and displacement field on the surface of damaged membrane material is explored,and its elongation at break and strain concentration coefficient are obtained.(3)Designing the biaxial tensile tests of various damaged membrane materials,the longitudinal and latitudinal stress and ultimate strain are studied correspondingly,the strain law of the whole field is analyzed,the load-strain characteristic curve is obtained,the strain field index of the membrane materials near the damage is analyzed,and the strain concentration coefficient of tensile fracture is obtained by comparing the influence of various damages on the far-field strength of the membrane materials.(4)Through biaxial cyclic tensile loading to obtain the longitudinal and latitudinal elastic modulus and Poisson's ratio of the damaged membrane.(5)Using ABAQUS finite element software,the simulation of uniaxial and biaxial tensile fracture of damaged membrane fabric including its warp and weft yarns and matrix is realized.The relative reliability of the numerical simulation results of the damaged membrane material is obtained by comparing the mechanical properties of the experiment.