关键词: 裂纹扩展速率, 内聚单元, 疲劳裂纹, 应力强度因子

Abstract: 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/dN. 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/dN 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.

Key words: cohesive element, crack growth rate, fatigue crack, stress intensity factor