基于弹塑性力学的疲劳裂纹扩展速率的研究

STUDY ON FATIGUE CRACK GROWTH RATE BASED ON ELASTIC⁃PLASTIC MECHANICS

基于增量塑性理论定义的J积分,结合试验和计算机仿真方法,研究建立基于弹塑性力学的裂纹扩展速率的方法,通过与基于线弹性力学的裂纹扩展速率曲线比较,基于增量塑性J积分的裂纹扩展速率曲线很好地描述了材料断裂力学性能特征,验证了ΔJ积分作为裂纹扩展驱动力参量的合理性,为进一步研究探讨裂纹扩展机制提供研究基础,并基于7N01铝合金试验数据提出了一种简单归一化模型,考虑了应力比对裂纹扩展速率的影响,适用于工程实际中估算材料的疲劳裂纹扩展寿命。

Definition based on the incremental theory of plasticity of J integral,combining the method of experiment and computer simulation,the method of crack propagation rate based on elastic⁃plastic mechanics is studied,the research shows that the crack growth rate curve obtained by the incremental plastic J integral is well described the material fracture mechanics performance characteristics,ΔJ integral as the crack growth driving force is verified the rationality of the parameters,in order to further research to explore mechanism of crack extension provides research foundation,a new model is proposed based on the 7N01 aluminum alloy test data,it takes into account the effect of stress ratio on crack propagation,and it is suitable for estimating fatigue life of materials in engineering practice.