【摘要】 【目的】焊接缺陷是影响焊接质量和结构性能的关键因素。通过试验和数值模拟探讨了焊接缺陷对Q450NQR1高强度耐候钢焊接接头疲劳寿命的影响及其评估方法。【方法】首先，制备含有不同缺陷的十字接头和对接接头试件，使用超声波检测法对试件缺陷进行定量分析，确保试件有效性；然后，对试件进行疲劳试验，基于英国标准BS7608:2014中的S-N曲线，分析不同缺陷类型十字焊接接头抗疲劳性能影响规律；最后，基于试件疲劳试验，提出一种含不同焊接缺陷接头的等效建模方法。【结果】结果表明，不同缺陷类型对十字焊接接头疲劳寿命的影响程度为咬边缺陷>错位缺陷>气孔缺陷，其对应的接头抗疲劳等级分别为F级、E级、D级，使用焊接缺陷等效建模法得到不同缺陷对应的等效初始裂纹值，并使用最小二乘法得到不同缺陷尺寸与等效初始裂纹尺寸的拟合结果，研究成果可为含缺陷的钢焊接结构疲劳寿命评估提供参考。更多还原

【Abstract】 [Objective] Welding defects are the key factors which affect the welding quality and structural property. In this research, the influence and evaluation method on the fatigue life of welded joints with welding defects, which was Q450 NQR1 high strength weathering steel, were discussed through tests and numerical simulation. [Methods] Firstly, cross joint and butt joint specimens with different defects were prepared, and the defects of the specimens were quantitatively analyzed by ultrasonic detection method in order to ensure the effectiveness of the test specimens. Secondly, fatigue tests were carried out. The influence regularity of the anti-fatigue performance of cross welded joints with different types of defects was analyzed based on the S-N curve of BS 7608:2014 standard. Finally, based on the tests, an equivalent modeling method for joints with different welding defects was proposed. [Results] The results show that the influence degree of different types of defects on the fatigue life of cross welded joints is as follows: undercut defect > misalignment defect > porosity defect, and the levels of anti-fatigue are F, E and D. The equivalent initial crack values of different defects were obtained by using the equivalent modeling method of welding defects. And the fitting results of different defect sizes and equivalent initial crack sizes were obtained by least square method. The research results can provide references for the fatigue life evaluation of steel welded structures with defects.更多还原