Dynamic Constitutive Model for Polymers Considered Hydrostatic Pressure and Strain Rate Dependency

Abstract

It is known that the dynamic behavior of polymers depends greatly on not only the strain rate but also the hydrostatic pressure, and furthermore, the volume change after plastic deformation is larger than that of the metal material. Therefore, it is necessary to clarify these material properties for high precision simulation of polymers. In this study, we developed a new constitutive equation considering the hydrostatic pressure dependence on the yield function and applying the strain rate dependence model T-M2009 for polymers, and implemented using the user subroutine function of the impact analysis code LS-DYNA. Then, tensile and compression dynamic tests were performed on polycarbonate using the Sensing Block Type High Speed Material Testing System, and material parameters of the developed constitutive equation were determined. Furthermore, verification simulation by LS-DYNA using these constituent equation and material parameters was carried out. As a result, the dynamic behavior of tensile and compression by simulation agreed well with the dynamic test results, and the validity of the constitutive equation and it's material parameters were confirmed.