Speckle Experiment And Finite Element Numerical Simulation On Wrinkled Deformation Of Flexible Membranes

Membrane materials has a widely use in areas engineering such as aerospace,flexible microelectronics fields,because of its light and flexible,playing a more and more important role in social life.Flexible membranes have been used as some key components of spacecraft like solar panels and inflatable antenna reflectors which work in thermo-mechanical coupling environment.Wrinkles are one of the most common forms of membrane structures.It has the most important influence on membrane structure.In the field of aerospace,it is treated as form of failure.The existence of folds in the flexible membrane circuit is beneficial to the structure itself.By controlling the folds of the flexible membrane,the performance of the flexible membrane device can be adjusted.In different fields,there are different requirements for the occurrence of membrane wrinkles or the distribution of wrinkles or even the Wrinkle amplitude of wrinkles.In the experiment,the tensile test of standard Kapton membrane specimen under different temperature conditions was carried out by using the digital speckle test system and the tensile testing machine equipped with constant temperature heating box.The stress-strain curves of materials were obtained,and the elastic modulus of materials at different temperatures was calculated,providing material parameters for numerical simulation.In this paper,the tensile wrinkles of square membranes with different thickness under different temperature conditions were studied.Membrane wavelength?amplitude at different temperatures are determined by experiments,and the critical load of wrinkles is determined.The influence of temperature and thickness on membrane wrinkle was studied by experiments.The generation and evolution of the wrinkle of membrane structure are also discussed.The tensile tests of square membranes with different square hole were also carried out to study the effect of different square hole on the membrane wrinkles.This experiment based on digital image correlation method,the displacement of the speckle is obtained by capturing the position changes before and after of the speckle the deformation of the membrane surface.In the process of data processing,will be involved in the coordinate system transformation,this paper will use MATLAB to process.The experimental error can be effectively reduced.In numerical simulation,theories about numerical simulation of membrane material are introduced in this essay.Based on the linear elastic material model,the numerical model of the square membrane is constructed.Nonlinear finite element simulation analysis is made for the tensile wrinkle.Results from numerical simulation are compared with that from experiments to validate whether numerical analysis is right.At the same time,numerical simulation is carried out for membranes with square hole and shear rectangular membrane.In addition,researches and analysis on convergence of numerical simulation solutions to problems such as membrane material's losing stability are conducted to give opinions or measurement of improving convergence.