Uniaxial tensile mechanical properties and model parameters determination of ethylene tetrafluoroethylene (ETFE) foils

On the other hand, a constitutive model based on viscoelasticity-plasticity of semicrystalline polymers is employed for ETFE foils. The material parameters are determined with a numerical method based on the Runge-Kutta and least squares methods. The numerical results are in good agreement with the experimental results with a maximum deviation of 6.2%, demonstrating that this model could correctly predict the stress-strain relation of ETFE foils.