平面ひずみ圧縮を受ける鋸歯状積層界面の成長挙動とその数値シミュレーション

Abstract

In the preceding work under plane strain compression of two blocks whose interface was sawtoothed, a peculiar behavior appeared such that the sawteeth grew markedly. But only the occurrence of the phenomenon itself was mentioned. In this paper, the degree of growth is experimentally investigated for various materials. Further, numerical simulations are carried out by the elastic-plastic FEM. Soft pure aluminum (A1050-O), soft or hard aluminum alloy (A5056-O, H) and copper (C1100-O, H) are used. The initial sawtooth angles of interface are 60° and 90°. In the experiments, the variations of the angle, area and side length of sawtooth are evaluated. In the FEM simulations the work hardening exponents are set at n=0.01, 0.15, 0.30, and the J2G constitutive equation is used. Corresponding to the experiment, shear-band formation is observed, and harder materials show a larger growth than the soft ones. The growth in the case of initial sawtooth angle 60° is larger than that in 90°. In the simulation of initial sawtooth angle 60° where n=0.01, the shear band appears and a lower n-value gives a larger growth. Based on the experiments and calculations performed here, this phenomenon is considered associated with the geometry and mechanical properties of the material. Especially, the shear-band formation from the tips of sawteeth governs the degree of growth. For comparison, the compression of axisymmetric blocks with sawtoothed interface is also performed. However, little growth appears in both the experiment and the corresponding calculation.