陶瓷材料SHPB实验的改进垫块法

An Improved Inserts form in SHPB Experiment for Ceramic Material

高强度陶瓷材料SHPB实验中,利用圆柱或圆台形垫块可避免压杆的端面塑性变形,但存在陶瓷试件中轴向的应力不均匀现象,从而影响实验结果的有效性。本文通过数值模拟分析了两种垫块方式引起的试件中轴向应力分布的特点,并以此为基础提出了一种更为合理的垫块方法。利用商业软件LS-DYNA,数值模拟了改进垫块方法的陶瓷材料SHPB实验。结果显示,基本上消除了陶瓷试件中轴向应力不均匀现象。应用一维应力波理论,分析了实验中的波传播过程,得到了对实验数据的修正处理方法,并证明了所提的修正方法是可行有效的。

In SHPB experiment of high-strength ceramic materials, the use of cylindrical inserts or conical shape inserts can avoid plastic deformation of pressure bar end face. However, both inserts may cause uneven axial stress in ceramic specimens, which affects the validity of experimental result. Numerical simulation of axial stress distribution characterisrics in specimen due to above mentioned inserts was carried out, based on which, a more reasonable inserts approach is proposed in this paper. By using commercial software LS-DYNA, SHPB experiment of ceramic material with improved inserts was numerically simulated. Results show that the uneven axial stress in ceramic specimen is basically eliminated. Applying one-dimensional stress wave theory, the wave propogation process in experiment was analyzed, the correction method of experimental data was obtained, and the feasibility and effectiveness of correction method was proved.