SHPB试验中粘弹性材料的应力均匀性分析

Analysis on stress uniformity of viscoelastic materials in split Hopkinson bar tests

采用特征线解法,对满足ZWT方程的粘弹性材料在高应变率SHPB试验中的应力均匀性进行了数值研究。着重分析了不同的材料本构粘性(松弛时间)、瞬态波阻抗比和入射波升时对于试样中应力均匀性、应变均匀性和平均应变率等的影响。为今后动态试验的试样设计提供了一定的理论依据。

By using characteristics method of wave propagation, the SHPB tests for the so-called ZWT viscoelastic materials are numerically studied to explore how the basic assumption of uniform distribution of stress along the length of specimen can be satisfied. It is found that the material parameters such as the relaxation time θ2 and the transient wave impedance ratio R1, as well as the rise time of incident wave all strongly influence the stress uniformity, the strain uniformity and the average strain rate of the tested specimen. Results may provide theoretical bases for the design of a dynamic test for viscoelastic material.