中文摘要：

基于ABAQUS有限元软件建立内聚单元模型以研究I型弹塑性疲劳裂纹的扩展过程。利用UEL子程序定义内聚单元的疲劳损伤累积准则以识别疲劳裂纹扩展过程中裂纹尖端的位置,并预测裂纹扩展速率da/d N。结果发现,预测的裂纹扩展速率与已有的试验结果吻合良好。通过ABAQUS软件中的温度-位移耦合分析方法同步获取裂纹扩展过程中因塑性变形能引起的裂纹尖端瞬态温度场的变化。结果显示,疲劳损伤累积准则所识别的裂纹尖端位置与裂纹扩展时最大温升点的位置具有一致性。这说明疲劳裂纹扩展过程中温度信号的变化也可以用于裂纹扩展规律的研究。基于数值模拟的方法验证了疲劳裂纹扩展过程中裂纹尖端的温升信号ΔT与裂纹扩展速率da/d N、应力强度因子范围ΔK之间的幂函数关系。研究成果有望用于疲劳裂纹扩展寿命的快速预测。

英文摘要：

A cohesive zone model is created to study the elastic-plastic fatigue crack growth process of Mode I crack based on the finite element software ABAQUS. The fatigue damage accumulative criterion is defined by the UEL subroutine in order to identify the location of the crack tip during the fatigue crack growth process, and to predict the crack growth rate da/d N. It is found that the predicted crack growth rates are in good accordance with the existing experimental results. The coupled temperature-displacement analysis in ABAQUS is used to synchronously obtain the variation of the transient temperature field due to the plastic deformation around the moving crack tip. The result shows that the location of the crack tip identified by the fatigue damage accumulative criterion is in good agreement with the point of the maximum temperature increment. This illustrates that the temperature signal during the crack growth process can be used to study the crack growth behavior. Based on the numerical simulation, the relationships between the temperature increment signals ΔT at the crack tip to the crack growth rates da/d N and the stress intensity factor ranges ΔK are found to be power law functions. The research achievement is expected to be used for rapid prediction of the fatigue crack propagation life.