An analysis of intersonic crack growth under shear loading
An analysis of intersonic crack growth under shear loading
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DOI：
10.1115/1.2791788
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发表时间：
1999-12
期刊：
影响因子：
--
通讯作者：
A. Needleman
中科院分区：
文献类型：
--
作者：
A. Needleman
数值分析了均匀弹性固体中裂纹在冲击剪切载荷条件下的扩展，裂纹被约束为沿着裂纹尖端正前方的弱面扩展。所分析的结构是Rosakis等人（1999）实验中使用的平面应变模型。一个内聚表面本构关系指定沿着弱面，涉及的牵引力和位移跨越它的跳跃，并允许创建新的自由表面。裂纹萌生阻力和裂纹速度的历史预测没有调用任何额外的故障准则。探讨了内聚强度和冲击脉冲时间对响应的影响。在一定的参数制度，计算再现，至少定性地，在实验中看到的裂纹速度的历史类型。对于其他参数值，可以看到从瑞利波速度下的裂纹扩展到剪切波速度的1.2倍以上的值的突然过渡。这种转变涉及主裂纹之前的微裂纹成核。在跨音速裂纹速度，冲击样梯度在近端应力场被发现在实验中看到的。
Crack growth in a homogeneous elastic solid under impact shear loading conditions is analyzed numerically, with the crack constrained to grow along a weak plane directly ahead of the initial crack tip. The configuration analyzed is a plane-strain model of that used in the experiments of Rosakis et al. (1999). A cohesive surface constitutive relation is specified along the weak plane that relates the tractions and displacement jumps across it and that allows for the creation of new free surface. The resistance to crack initiation and the crack speed history are predicted without invoking any additional failure criterion. The effect of cohesive strength and impact pulse time on the response is explored. In a certain parameter regime, the calculations reproduce, at least qualitatively, the type of crack speed histories seen in the experiments. For other parameter values, an abrupt transition from crack growth at the Rayleigh wave speed to a value above √2 times the shear wave speed is seen. This transition involves microcrack nucleation ahead of the main crack. At intersonic crack speeds, shock-like gradients in the near-tip stress field are found as seen in the experiments.