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本文在Newman裂纹闭合模型的基础上,以裂纹面附加残留位移为主要线索,综合考虑了渗层组织、强度、初始残留应力分布及残余奥氏体转变对裂纹闭合行为的影响,提出了一个渗碳硬层疲劳裂纹闭合计算模型。文中利用该模型对疲劳裂纹扩张过程中卸载后裂纹面接触应力的分布、渗层裂纹闭合效应进行了成功地计算;借助于实测的渗碳层da/dn—ΔK_(eff)关系,较好地预测了渗层裂纹扩张速率的变化规律;并在定量分析残余奥氏体转变、初始残留应力分布对闭合行为的影响方面进行了有益的尝试。
Based on the Newman crack closure model, the residual displacement of the crack surface is taken as the main clue. Considering the influence of the microstructure, strength, initial residual stress distribution and residual austenite transformation on the crack closure behavior, a permeability Fatigue Crack Closure Calculation Model of Carbon Hard Layers. The model was used to calculate the contact stress distribution and crack closure effect of crack surface after unloading in the process of fatigue crack expansion. By means of the measured da / dn-ΔK eff relationship, The variation regularity of the crack propagation rate was predicted, and a useful attempt was made to quantitatively analyze the effect of residual austenite transformation and initial residual stress distribution on the closing behavior.