压剪联合冲击下K9玻璃中的失效波

对K9玻璃进行了冲击速度为150~400 m/s,倾斜角为10、15的纵剖试样斜撞击实验。结果表明，在加载剪切横波(S+)和卸载纵波(P-)之间有波速超过了纵波波速的波阵面存在，此波的存在对卸载纵波和卸载横波的幅值有一定的影响。由于失效波的产生与材料的表面性质密切相关，为消除纵剖试样中间界面的影响，模拟VISAR的实验条件，进行了冲击速度为70~300 m/s、倾斜角为10的横剖试样斜撞击实验。可以确定在此冲击范围失效波的波速在0.98~1.4 km/s，产生失效波的临界状态为：压应力0.86~1.01 GPa，对应剪应力0.053~0.071 GPa。表明剪应力的存在极大降低了失效波产生的阈值。在此基础上初步分析了撞击面的动摩擦因数和相对滑移速度。

Experimental investigation on failure wave in K9 glass under combined pressure and shear impact loading

To investigate the effects of shear stress to failure wave,series of experiments including oblique planar impact with inclination angle 10 and 15 degree,impact loading velocity ranging from 150 m/s to 400 m/s for K9 glass of central cut sample,are carried out in the present paper.Experimental results show that there existed a wave front with wave velocity exceeding that of longitudinal wave between the loading transversal wave and the unloading longitudinal wave.The wave has affected the amplitude of the unloading waves.Since the wave might be generated for the existing of central surface in central cut sample,some experiments including oblique planar impact with inclination angle 10 degree and impact loading velocity ranging from 70 m/s to 300 m/s for K9 glass of across cut sample are carried out in succession to eliminate the effect of central surface.In these experiments,the wave velocity of failure wave is determined to be 0.98~1.4 km/s and corresponding critical value for failure wave under combined pressure and shear impact loading are pressure 0.86~101 GPa and shear 0.053~0.071 GPa.All these show that shear stress may greatly decrease the critical value for failure wave.Some preliminarily discussions on dynamic friction coefficients and sliding velocity of impact surface are also conducted.