【摘要】 岩石、陶瓷或混凝土等脆性材料 ,在用 Hopkinson压杆对其实施高应变率加载实验时 ,由于其破坏应变很小 ,试件通常在加载入射波的波头部分 (含初始上升沿和较大的弥散振荡部分 )就已破坏失效 ,因此采用常规的实验或数据处理方法很难得到精确有效的实验结果 .本文提出的 Hopkinson压杆装置预留间隙实验法能使加载入射波波幅振荡明显减小且初始上升时间为零 ,有效地减小了弹性波弥散带来的误差 ,使贴于压杆中部的应变片测得的信号经处理后很大程度上直接反映的是试件端面的实际受力状态 ,且由于避免了试件在加载波上升沿段的不稳定受力而使应变率历史曲线更趋于恒定 ,这为提高 Hopkinson压杆装置的实验精度 ,特别是为脆性材料提供了一种实施高应变率实验的实用可行的途径 .更多还原

【Abstract】 Because of the too small damage strain of brittle materials such as rock, ceramic or concrete, the specimen always breaks during the initial rising slope or oscillatory part of loading waves, and this makes it impossible to obtain their absolute properties under high stain rate by conventional Hopkinson pressure bar technique. An novel experimental method, pre-gap method, presented here can make the incident wave have no initial rising slope and less oscillation, which can diminish the errors effectively in test results caused by wave dispersion. In addition, this method can also make the strain rate history even more constant, as the specimen avoids being compressed under the unstable rising slope of loading waves. Therefore, this pre-gap method can not only improve the accuracy of test results, but also afford a special and feasible way to perform high strain rate tests on brittle materials by Hopkinson pressure bar.更多还原