力学不均匀性对焊接接头疲劳裂纹扩展的影响

Effect of mechanical heterogeneity on fatigue crack propagation in welded joints

关键词:  焊接接头  不均匀性  疲劳裂纹

Key words:  welded joint  heterogeneity  fatigue crack propagation

摘要:

提出了软对硬不均匀裂纹体(裂纹在硬区)的研究模型。试验表明,力学不均匀性影响疲劳裂纹扩展速率。边界元的动态分析指出,在相同扩展步下,裂纹离软硬区界面越近,J积分的幅值△J越小。不均匀性对疲劳裂纹扩展速率的影响,主要是通过对△J的影响来实现的。裂纹离软硬区界面越近,疲劳裂纹扩展速率越小。

Abstract:

In this paper,a soft-hard heterogencous cracked body has been established as the model for analysis.The fatigue testing of the heterogeneous plates showed that the mechanical heterogeneity affected the fatigue crack growth rate.The numerical simulation of BEM,boundary element method,was used for analysing the heterogeneous fatigue bodies.The smaller the distance between the crack surface and the interface of soft-hard region is,the smaller △J (the amplitude of J-integral in the same growth step) is,and the fatigue crack growth rate become.The influence of heterogeneity on the fatigue crack growth rate is mainly determined by △J.