Abstract

Recent experimental studies on spall fracture show that the impact parameters can lead to instabilities in the strain rate dependence of the dynamic strength of the material. Here we consider the effect of the dynamic impact parameters on the time dependences of the material ultimate stress. Numerical modeling of spall fracture is conducted for ultrapure aluminum. The stress-time relations are obtained from a one-dimensional wave problem using an elastic formulation. The fracture conditions are determined by the incubation time criterion for spall fracture. The obtained results show that the dynamic strength can depend not only on the strain rate, but also on other impact time parameters. The structural-temporal approach used in fracture modeling allows taking into account the loading history, which makes it a convenient tool for considering the corresponding effects. The dynamic strength is calculated with varying impact time parameters. The strain rate dependences of the ultimate stresses obtained for different types of impact are found to be different, which is also consistent with experimental data.

中文翻译：

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冲击时间参数对层裂断裂动态强度的影响

摘要

最近的剥落断裂实验研究表明，冲击参数可能导致材料动态强度的应变率依赖性不稳定性。在这里，我们考虑动态冲击参数对材料极限应力的时间依赖性的影响。对超纯铝进行了剥落断裂的数值模拟。应力-时间关系是使用弹性公式从一维波浪问题获得的。断裂条件由剥落断裂的保温时间标准确定。所得结果表明，动态强度不仅取决于应变率，而且还取决于其他冲击时间参数。裂缝建模中使用的结构时态方法考虑了加载历史，这使其成为考虑相应效果的便捷工具。动态强度是通过改变冲击时间参数来计算的。发现对于不同类型的冲击获得的极限应力的应变率依赖性是不同的，这也与实验数据一致。