Abstract

The paper discusses the dynamic propagation of cracks in brittle materials under various loads. The crack propagation is studied under both quasi-static and the shock-pulse loading conditions. Particular attention is paid to the dependences characterizing the crack propagation and having a non-stationary character. Thus, for the case of crack propagation under quasi-static loading, the crack velocity oscillations phenomenon is investigated. The problem related to the scatter of the stress intensity factor values which is observed in a number of experiments in course of the crack propagation under high-rate loading conditions is studied. The studies have been carried out using the finite element method with the structure–time fracture which is introduced into the computational scheme and which fundamentally determines the discrete mechanism of the fracture processes at a given scale level. Both quantitative and qualitative comparison of the calculation results with the available experimental data has been carried out. It is shown that taking into account the spatial and temporal discretization of the process makes it possible to explain a number of experimentally observed effects that do not fit into the traditional theoretical concepts of the dynamic fracture theory.

中文翻译：

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时空谨慎作为动态断裂过程的关键属性

摘要

本文讨论了在各种载荷下脆性材料中裂纹的动态传播。在准静态和冲击脉冲载荷条件下研究了裂纹的扩展。要特别注意表征裂纹扩展和具有非平稳特性的依赖性。因此，对于准静态载荷下的裂纹扩展情况，研究了裂纹速度振荡现象。研究了在高载荷条件下裂纹扩展过程中在许多实验中观察到的与应力强度因子值分散有关的问题。已经使用有限元方法对结构-时间裂缝进行了研究，该结构-时间裂缝被引入到计算方案中，并且从根本上确定了给定尺度下裂缝过程的离散机制。已经将计算结果与可用的实验数据进行了定量和定性比较。结果表明，考虑到过程的时空离散，可以解释许多实验观察到的效果，这些效果不符合动态裂缝理论的传统理论概念。