用于高强度材料的SHPB实验添加垫块法

提出了用于高强度材料的改进的SHPB实验方法添加垫块法,运用数值模拟方法,利用有限元程序LS-DYNA3D分析了添加垫块实验方法的合理性和可行性。根据一维应力波理论,给出了数据处理的修正方法。作为应用实例,采用改进的实验方法对高强度的Al2O3陶瓷材料的动态力学性能进行了研究,得到了比常规方法较高的应变率及应力应变范围的动态应力应变曲线,表明Al2O3陶瓷为应变率相关的非线性弹脆性材料。结果表明,添加垫块实验方法可有效地防止实验中压杆端面的变形,提高试件的应力应变及应变率水平。添加垫块实验方法为在SHPB装置上实现高强度材料的动态实验提供了一种方便实用的途径。

A Setting-platen Experimental Method on SHPB System for High-strength Materials

An improved experimental method, so called setting-platen method, on Split Hopkinson Pressure Bar system for high-strength materials is presented. The reasonableness and feasibility of the improved SHPB method are analyzed by numerical simulation using the finite element code LS-LYNA3D. According to the theory of one-dimensional stress wave, the modification method on data handling is given. As an instance, the dynamic mechanical property of high-strength Al_2O_3 ceramics is investigated using the improved technique of SHPB. The dynamic stress-strain curves are obtained in the range of higher strain rates and higher stress and strain than that by using the conventional SHPB method. It is shown that Al_2O_3 ceramic is a nonlinear elastic-brittle material and sensitive to strain-rate. It is indicated that the deformation and damage of the bar ends can be prevented effectively by using setting-platen method and the stress, strain and strain rate of specimen can be improved so as to meet the demand of research. The setting-platen method affords a special and feasible way to perform high strain rate dynamic tests on high-strength materials by SHPB technology.