On the validity of strain energy density criterion for mixed mode I/II fracture analysis of notched shape memory alloy components
On the validity of strain energy density criterion for mixed mode I/II fracture analysis of notched shape memory alloy components
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DOI：
10.1016/j.engfracmech.2019.03.014
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发表时间：
2019-06
影响因子：
5.4
通讯作者：
M. Mirsayar;D. Hartl
中科院分区：
文献类型：
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作者：
M. Mirsayar;D. Hartl
本文首次采用应变能密度（SED）方法研究了多晶形状记忆合金缺口构件在拉伸/剪切复合载荷作用下的断裂行为。SED方法已被广泛用于探索断裂路径和由常规韧性金属制成的缺口部件中的断裂起始（例如，铝）以及脆性和准脆性材料，但迄今为止尚未涉及其在形状记忆合金中的应用。对于一个缺口多晶形状记忆合金组件进行热机械载荷，不同的材料参数，包括最大相变应变，杨氏模量，和温度上的SED分布在缺口尖端和断裂角的影响进行了探索和讨论。部署用于估计的转换区和应变场的理论公式的有效性进行检查，通过比较封闭形式的解决方案，从可比的有限元计算得到的结果。结果表明，SED方法的效率是有限的归一化的最大相变应变的归一化的有效缺口应力强度因子的比率超过一个临界值，这样的条件以前没有报道的非相变金属。最后，缺口尖端半径的断裂角和SED分布周围的缺口尖端的影响进行了评估。
This paper investigates the fracture behavior of notched polycrystalline shape memory alloy components utilizing the strain energy density (SED) approach and considering combined tensile/shear loading for the first time. The SED approach has been widely used to explore fracture paths and the onset of fracture in notched components made of conventional ductile metals (e.g., aluminum) as well as brittle and quasi-brittle materials, but its application to shape memory alloys has heretofore not been addressed. For a notched polycrystalline shape memory alloy component subjected to thermomechanical loading, the effects of different material parameters including maximum transformation strain, Young’s modulus, and temperature on the SED distribution around notch tip and the fracture angle are explored and discussed. The validity of the theoretical formulations deployed for estimation of the transformation zones and strain fields are examined by comparing closed-form solutions with the results obtained from comparable finite element calculations. It is shown that the efficiency of the SED approach is limited as the ratio of the normalized maximum transformation strain to the normalized effective notch stress intensity factor exceeds a critical value; such conditions have not been previously reported for non-transforming metals. Finally, the effects of the notch tip radius on the fracture angle and SED distribution around the notch tip are evaluated.