岩石类介质SHPB试验加载波形的数值分析

Numerical Analysis of Loading Waveform in SHPB Tests of Rock-Like Medium

采用基于细观损伤力学基础而开发的动态岩石破裂过程分析系统RFPA2D对大直径SHPB装置中压杆的应力波弥散效应进行二维数值分析,讨论了矩形应力脉冲和三角形应力脉冲两种加载波形对弥散结果的影响.结果表明,基于细观损伤力学基础而开发的动态岩石破裂过程分析系统RFPA2D能够较真实地模拟SHPB试验中波形传播过程;在大直径SHPB实验技术中,由于压杆的横向泊松效应,波形在传播过程中的弥散现象明显;选择合适的加载波形可以有效降低SHPB装置中应力波的弥散效应,其中三角形波加载可以降低大直径SHPB动态测试中的应力波弥散,是岩石混凝土等非均匀材料SHPB动态测试的较理想加载波形.

Based on mesoscopic damage mechanics, the dynamic numerical code RFPA^2D is developed to simulate the dispersion in wave propagation due to radial inertia effect in large diameter split Hopkinson pressure bar （SHPB）, and the influences of waveform such as rectangle stress pulse and triangle stress pulse loaded to incident bar on the dispersion are simulated and analyzed. The results of numerical analysis indicated that the dynamic numerical code RFPA^2D can simulate really the process of stress wave propagation in the pressure bar; when the diameter of SHPB is large, the geometric dispersion effect due to radial inertia become very important; when the appropriate waveform is loaded, the dispersion effect in wave propagation can be reduced, and the triangle wave which may reduce dispersion effect is an appropriate loading waveform in dynamic test of inhomogeneous mediums by using SHPB such as rock and concrete.