Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : October 07, 2017 - October 09, 2017
Polymer foam is widely used in the engineering field because of various properties, e.g., lightweight, shock absorbing, insulation. However, the strength of the foam material dramatically decreases with the increase in the volume fraction of the pore. Therefore, evaluating the mechanical response and the strain distribution provides important information to understand mechanical properties of the polymer foam. In this study, three-dimensional non-uniform deformation behavior of low density polyethylene foam specimens having curvature of gage area during the tensile test is investigated by using the three-dimensional digital image correlation method. Effects of foaming method, expansion ratio and specimen size on the tensile test are evaluated. The microscopic structure such as cell size and connection of cells is observed by using X-ray CT. A remarkable strain concentration in the tensile direction was caused by the curvature of specimen. The strain in thickness direction distributed non-uniformly as well as the strain in tensile direction. However, the strain in width direction shows almost uniform distribution even in large deformation range. Large volume change caused in open-cell foam microstructure while almost no volume change was confirmed in closed-cell foam.
