不同应力状态下TiB2/Al复合材料的断裂行为:失效判据校准与评价

Fracture behavior of TiB2/Al composite under different stress states: Calibration and evaluation of fracture criteria

  • 摘要: 复杂应力状态下韧性材料的变形和断裂行为与单轴加载通常具有很大差别,因此近年来失效判据的发展及其在仿真领域的应用得到广泛关注,分析不同失效判据模型在较宽应力状态范围内的适用性差异,并选择合适的模型对于精准地预测工程材料断裂行为至关重要。为了探究原位自生TiB2/Al复合材料的断裂行为,在不同应力状态(应力三轴度−0.82~1.03,Lode角参数−1~1)下进行了系统的断裂试验和微观分析,结果表明该材料的断裂行为和微观机制与应力状态密切相关;除了应力三轴度外,失效判据模型中应该进一步考虑Lode角参数影响以更精确预测宽应力状态下的断裂行为。基于系统的试验结果,对5种典型的失效判据模型参数进行标定,并详细对比和评价了这些模型在宽应力状态范围内对断裂行为的预测能力。结果表明,全面考虑应力三轴度、Lode角参数和截断值的失效判据模型能够更准确地描述复合材料在复杂应力状态下的断裂行为。

     

    Abstract: The deformation and fracture behaviors of ductile materials under complex stress states are usually quite different from those under uniaxial loading conditions. In recent years, the development of fracture criteria and their application in numerical simulation have attracted great attention in many engineering fields. So, it is quite important to analyze the applicability of different fracture criteria over a wide range of stress states and select an appropriate model to accurately predict the fracture behavior. The fracture behavior of in-situ TiB2/2024 Al composite was investigated systematically over stress triaxialities ranging from −0.82 to 1.03, and lode angel parameters ranging from −1 to 1 by using an experimental approach. The fracture characteristics and underlying mechanisms are closely related to stress state, and both of the stress triaxiality and lode angle parameter should be included in the fracture criterion to predict fracture over a wide range of stress states. Based on the experimental data, five existing fracture criteria were calibrated, and their ability to describe and predict the fracture behavior was evaluated. The result shows that the fracture criteria which consider comprehensively the effects of the stress triaxiality, lode angle parameter and cut-off value can more accurately predict the fracture behavior of in-situ TiB2/2024 Al composite over a wide range of stress states.

     

/

返回文章
返回