Validation and Material Modeling of Polymers by Employing MAT_SAMP-1

We have developed a method to determine plastic Poisson’s ratio and its corresponding stress – strain curves, where newly redefined true stress expression including elastic and plastic Poisson’s ratios is employed. The plastic Poisson’s ratio is used to predict permanent volumetric deformation which is one of the mechanical characters associated with crazing. Although the crazing is one of the most important issues to be tackled in analysis, methods to determine the plastic Poisson’s ratio and its corresponding data have not been discussed sufficiently in previous papers. Thus we show and discuss how we determine and validate these data. Additionally, in order to complement the method, we provide two techniques to utilize MLYS (Multi-Linear Yield Surface) and to evaluate damage property. We show MLYS could make analysis incorporating isochoric plasticity in compressive state stable. Furthermore we show that these methods are valid and useful through the numerical results.