【摘要】 由试验获得桥梁用钢14MnNbq焊接件的疲劳裂纹扩展da/dN、ΔK数据点及其疲劳门槛值ΔKth,断裂韧性Kc近似采用相同厚度母材试样得到的结果。采用四参数Forman公式利用多元线性回归法拟合试验数据,给出了14MnNbq焊接件的全范围疲劳裂纹扩展的表达式。在应力比R=0.05,0.25,0.50条件下Forman公式拟合曲线与试验数据吻合较好;相对于母材而言,在疲劳开裂和稳定扩展初期焊接件疲劳裂纹扩展速率较高。更多还原

【Abstract】 The fatigue crack growth data points da/dN～ΔK and fatigue threshold value ΔK_th of bridge steel 14MnNbq welds are obtained through experiments,while the result of fracture toughness K_c is obtained by approximately using specimen of parent metal of same thickness.A 4-parameter Forman formula is then used to present the expression of the full range fatigue crack growth of 14MnNbq welds through fitting the experimental data by multivariate linear regression method.It is found that the fitting curves from Forman formula agree fairly well with the data of the experiments under condition that three different stress ratios R=0.05,0.25 and 0.50.In comparison to the parent metal,the fatigue crack growth rate of the welds is rather great at the initial time of fatigue crack and stable growth of the crack.更多还原