一种新的高应变率复合压剪实验技术

提出了一种新的基于Hopkinson杆实验技术的在102~103s-1高应变率下实现压剪复合加载的实验装置,并给出了相应的理论分析和数值模拟。为了获取材料在复杂应力下的本构关系,借助斜飞片冲击实验的思想,对Hopkinson杆进行改造,将入射杆的末端改进为截锥形,以便在试样中同时产生压缩和剪切应力。利用有限元分析软件LS-DYNA对试样中的应力波传播进行模拟计算,并利用改进装置进行了初步实验。计算和分析结果表明,利用所设计的装置可以实现对试样的动态压剪复合加载,获得材料在高应变率复杂应力加载下的本构响应,进而建立材料在复杂应力状态下本构行为的描述。

A New Combined Compression-shear Loading Technique at High Strain Rates

Based on the modified split Hopkinson bar(SHB),a new planar dynamic loading technique combining compression-shear under strain rates in range of 10~2~10~3s~-1 is proposed in this paper.In order to generate shear and compressive stresses simultaneously in specimen,the oblique-plate impact experiment is introduced.The end surface of the input bar is improved in the shape of cut-cone.The main purpose of this work is to acquire the constitutive equation under complex stresses loaded at high strain-rates.Related theoretic analysis and numerical simulation prediction of the technique are presented.The stress wave propagation in the specimen is calculated by using the explicit dynamic FEM-code LS-DYNA.A preliminary test is carried out.The results of the simulation and test show that the combined compression-shear loading can be realized in the specimen by this technique,Therefore a systematic understanding on complicated mechanical properties of the materials can be obtained with this technique.