Numerical Analysis on Compressive Deformation Behavior of Porous Polymer with High Initial Relative Density
Isamu RIKU and Koji MIMURA
Abstract:In this study, we employ the two-dimensional homogenization model based on molecular chain network theory to investigate the micro- to macroscopic mechanical behavior of porous polymer under macroscopic uniform compression. A parametric study is performed to quantify the effect of a characteristic value of polymer matrix, the distribution and the initial volume fraction of voids, and the macroscopic triaxiality of loading condition on the deformation behavior of porous polymer. The results suggest that the initial elastic modulus and the macroscopic yield stress of porous polymer have no dependence on the characteristic value of polymer matrix. The onset of localized shear band at the ligament between voids leads to the macroscopic yield of porous polymer. Furthermore, the microscopic localized shear deformation behavior is promoted in case of high initial volume fraction of voids and high triaxiality loading condition, which results in the early appearance of the macroscopic yield. After the macroscopic yield, microsopic buckling onsets at the ligament between voids and a remarkable strain hardening occurs in case of high initial volume fraction of voids and high triaxiality loading condition due to the considerable increase of the density of porous polymer. Key Words:Porous polymer, Molecular chain network theory, Homogenization method, Shear band, Microscopic buckling