冲击波作用下铝的等效剪切模量

提出了冲击波作用下通过测量沿着准弹性卸载过程纵波波速与体波波速得到等效剪切模量的方法，应用该方法对LY12铝在20—70 GPa冲击压力下的等效剪切模量进行了测量.实验结果表明，等效剪切模量随应力线性减少直至反向屈服时为零，而初始卸载时的等效剪切模量可以由修正的Steinberg-Cochran-Guinan模型进行描述.应用得到的等效剪切模量进行了初步数值模拟，计算结果与实验测量的粒子速度剖面符合很好，重现了准弹性卸载到塑性卸载的光滑过渡. 关键词： 等效剪切模量 波速 准弹性卸载 冲击波 铝

Effective shear modulus in shock-compressed aluminum

A method to determine the effective shear modulus under shock loading conditions by using longitudinal and bulk sound velocities along the quasi-elastic release was introduced in present paper. The effective shear modulus was calculated for LY12 aluminum over shock pressures range of 20—70 GPa. Results show that the effective shear modulus decreases linearly with the stress, reaching to zero at the reverse yield point, and the effective shear modulus at first release can be depicted by the modified Steinberg-Cochran-Guinan model. Using the effective shear modulus data, simulation has been successful in reproducing the experimental data with quasi-elastic release behavior, showing smooth transition from elastic wave to fully plastic wave.