Fatigue experiments and numerical simulations based on the linear elastic fracture mechanics (LEFM) theory were conducted on the evenmatched (EM) and undermatched (UM) 10CrNi3MoV load-carrying cruciform welded joints (LCWJs). The study firstly experimentally investigated the fatigue crack growth rate (FCGR) of base metal, EM, and UM weldments. The corresponding Paris parameters as essential input data are provided to assess the fatigue crack propagation behavior for weld toe and weld root failure caused by notch stress concentration variations. On the one hand, the stress intensity factors (SIFs) at weld toe and weld root were calculated considering the effects of LCWJ specimen geometries, initial crack types, and sizes. The comparisons between simulated results and standards analytical solutions were executed, which exhibit good accordance. It proved that the fatigue fracture simulation procedure based on LEFM is appropriate for the fatigue assessment of LCWJs. Eventually, it conducted the parametric analysis by predicted S–N curves, which included in the weld length, initial crack shape, initial crack size, penetration length, and materials fracture parameter, to explore some safety assessment reference lines for both failure modes of LCWJ.

中文翻译：

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考虑失配效应的10CrNi3MoV焊接承载十字接头疲劳断裂评价

基于线弹性断裂力学 (LEFM) 理论的疲劳实验和数值模拟在偶匹配 (EM) 和欠匹配 (UM) 10CrNi3MoV 承载十字形焊接接头 (LCWJ) 上进行。该研究首先通过实验研究了母材、EM 和 UM 焊件的疲劳裂纹扩展率 (FCGR)。提供相应的巴黎参数作为基本输入数据，以评估由缺口应力集中变化引起的焊趾和焊根失效的疲劳裂纹扩展行为。一方面，考虑 LCWJ 试样几何形状、初始裂纹类型和尺寸的影响，计算焊趾和焊根处的应力强度因子 (SIF)。对模拟结果与标准解析解进行了比较，表现出良好的一致性。证明基于LEFM的疲劳断裂模拟程序适用于LCWJ的疲劳评估。最终，它通过预测进行了参数分析S - N曲线，包括焊缝长度、初始裂纹形状、初始裂纹尺寸、熔深长度和材料断裂参数，以探索 LCWJ 两种失效模式的一些安全评估参考线。