SHPB冲击压缩实验中泡沫塑料应力均匀化过程的数值模拟

对SHPB实验中泡沫塑料的本构关系进行了分段线性化处理，基于一维弹性应力波理论用数值方法对变形过程进行了模拟。结果表明，实验初期试件处于严重的应力不均匀状态；并且由于试件与输入／输出杆的界面处存在波阻抗不匹配现象，实验中后期的应力均匀化程度也无法得到有效提高；若将子弹及输入／输出杆的材料更换为刚度较低的聚合物，可有效地减少波阻抗不匹配的程度，从而使实验中后期的应力均匀化水平得以大幅度提高，但实验所能够达到的最大应变值可能受到限制。

Numerical Simulation of Stress Homogenization in Foamed Plastics in Split Hopkinson Pressure Bar Experiment

Based on stress wave theory of one dimension and piece-wise linearization of constitutive relation, the deformation process of foamed plastics in SHPB experiment is simulated by numerical method. The result indicates that the stress nonhomogeneity of specimen in the initial stage of experiment is very notable, and the level of stress homogenization can not be improved effectively during the middle stage and final stage of experiment because of the mismatch of wave impedances between the input/output bars and the specimen. The mismatch of wave impedances is reduced while the materials of the striker and input/putput bars are replaced by polymers which have lower stiffiness, and the level of stress homogenization will be improved significantly in the middle stage and final stage of experiment. However, the maximum of strain to be achieved in the experiment might be limited.