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本文的目的在于研究疲劳载荷下的焊趾裂纹扩展规律,并通过它来分析有限长度焊趾裂纹前沿的应力强度因子分布。试验采用LY—12R 铝合金制成几种焊趾裂纹的模拟试样。用疲劳勾线法求出前沿各点的裂纹扩展速率并与平板表面裂纹试样进行了对比.认为:中心加载焊趾裂纹在长度方向的扩展速率高于中心加载平板表面裂纹;偏心加载焊趾裂纹在长度方向的扩展速率高于中心加载扩展速率。随着相对偏心的提高,裂纹沿长度方向的扩展速率亦增加;表面残余压应力可以有效地抑制焊趾裂纹在长度方向的扩展速率.
The purpose of this paper is to study the crack propagation law of weld toe under fatigue loading and to analyze the stress intensity factor distribution of the weld toe crack front with finite length. Test using LY-12R aluminum alloy weld toe cracks made of several simulated samples. The fatigue crackline method was used to calculate the crack growth rate at each point of the front and compared with that of the flat surface cracks.The results show that the crack growth rate in the longitudinal direction is higher than that of the center load plate, The crack growth rate in the length direction is higher than the center load expansion rate. With the increase of relative eccentricity, the crack growth rate along the lengthwise direction also increases. The surface residual compressive stress can effectively suppress the crack growth in the length direction of the weld toe crack.