Development of Dynamic and Impact Load-Measuring Apparatus with Opposite Load-Cells

Abstract

　　　It is necessary to evaluate the mechanical properties at wide range of strain rates, since the general materials have the strain rate dependence of strength. In high strain rate (impact strain rate: 10²~10⁴ s^-1) test, split Hopkinson pressure bar (SHPB) or direct-impact Hopkinson pressure bar (DHPB) methods are used. However, these methods cannot be compatible with load equilibaium evaluation and large deformation. In addition, these methods only evaluate the mechanical properties at the impact strain rate. From the viewpoint of development of constitutive equation including strain rate effect, evaluation at dynamic strain rate (10⁰~10¹ s^-1), which is intermediate strain rate between quasi-static and impact strain rates, is important factor. In this study, we developed new compressive test, dynamic and impact load-measuring apparatus with opposite load-cells, which can resolve above problems. In order to measure large deformation at dynamic and impact deformation, universal rate range load-cell, which can reduce the influence of the reflected stress wave, was used. In addition, load equilibrium can evaluate using opposite load-cells which consist of movable and stationary load-cells. It was confirmed that this new apparatus have utility through the evaluation of strain rate dependence of strength for pure aluminum and impact deformation for porous aluminum.