Stable Crack Growth During Thermal Actuation of Shape Memory Alloys
Stable Crack Growth During Thermal Actuation of Shape Memory Alloys
复制标题
形状记忆合金热驱动过程中稳定的裂纹扩展
DOI：
10.1007/s40830-015-0046-8
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发表时间：
2016
影响因子：
2.2
通讯作者：
D. Lagoudas
中科院分区：
文献类型：
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作者：
S. Jape;T. Baxevanis;D. Lagoudas
对形状记忆合金在平面应变、模式I、恒定外加载荷下受到热变化时的裂纹扩展进行了有限元分析。假设裂纹在裂纹尖端能量释放率的临界水平下扩展，该临界水平是使用虚拟裂纹闭合技术建模的。假设在奥氏体相稳定的高温下施加的载荷水平足够低，使得所得的裂纹尖端能量释放速率小于临界值，但足够高，使得在冷却期间达到临界值，从而引发裂纹生长（Amkevanis和Lagoudas in Int J Fact 191：191-213，2015）。观察到稳定的裂纹扩展，主要与前进裂纹的尾流中留下的转化材料的屏蔽效应有关。结果有关的近尖端的机械领域和断裂韧性的相变指标和偏置载荷水平的敏感性进行了研究。
A finite element analysis of crack growth is carried out in shape memory alloys subjected to thermal variations under plane strain, mode I, constant applied loading. The crack is assumed to propagate at a critical level of the crack-tip energy release rate which is modeled using the virtual crack closure technique. The load level, applied at a high temperature at which the austenite phase is stable, is assumed sufficiently low so that the resulting crack-tip energy release rate is smaller than the critical value but sufficiently high so that the critical value is reached during cooling, initiating crack growth (Baxevanis and Lagoudas in Int J Fract 191:191–213, 2015). Stable crack growth is observed, mainly associated with the shielding effect of the transformed material left in the wake of the advancing crack. Results pertaining to the near-tip mechanical fields and fracture toughness are presented and their sensitivity to phase transformation metrics and bias load levels is investigated.