An experimental and numerical research program is executed to investigate the fatigue lifetime increase due to grinding-type post-weld treatment method. Plate edge gusset, longitudinal attachment and T-type joint specimens are investigated using fatigue test results, numerical models and mathematical statistical tools. The favourable impact of grinding on fatigue lifetime of the analysed joints is commonly known for researchers. However, considering the lifetime increasing effect is mainly based on experimental results. In the current research program, numerical models for as-welded and post-weld-treated specimens are developed and the lifetime increasing effect of weld treatment is investigated using effective notch stress (ENS) method. Fatigue tests are executed on as-welded and weld-treated specimens, and their results are comparatively evaluated based on numerical calculations and measured lifetimes. The results prove that the fatigue lifetime of weld treated (ground) details can be predicted with high accuracy by applying modified weld geometry in the numerical model and ENS method. Based on the current investigation, it is proved that the advantage of weld geometry treatment method comes mainly from the modification of the weld geometry at the fatigue critical point. Results also show that the same S-N curve can be applied for both as-welded and ground specimens, if the modified weld geometry is implemented in the numerical model.

中文翻译：

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使用有效缺口应力评估磨焊缝处理方法

执行了一个实验和数值研究程序，以研究由于磨削型焊后处理方法而导致的疲劳寿命增加。使用疲劳测试结果，数值模型和数学统计工具对板边缘角撑板，纵向附着物和T型接头试样进行了研究。研究人员普遍知道，磨削对所分析接头的疲劳寿命产生有利影响。但是，考虑延长寿命的效果主要是基于实验结果。在当前的研究计划中，开发了用于焊接后和焊接后试样的数值模型，并使用有效缺口应力（ENS）方法研究了焊接处理的寿命增加效果。对焊接后和焊接后的试样进行疲劳测试，根据数值计算和测得的使用寿命对它们的结果进行比较评估。结果证明，通过在数值模型和ENS方法中应用改进的焊接几何形状，可以高精度地预测焊接处理（地面）零件的疲劳寿命。根据目前的研究，证明了焊缝几何形状处理方法的优点主要来自于在疲劳临界点处对焊缝几何形状的修改。结果还表明，如果在数值模型中实现了修改的焊缝几何形状，则同样的SN曲线可以应用于焊接的和磨碎的试样。结果证明，通过在数值模型和ENS方法中应用修改后的焊缝几何形状，可以高精度地预测焊缝（地面）零件的疲劳寿命。根据目前的研究，证明了焊缝几何形状处理方法的优点主要来自于在疲劳临界点处对焊缝几何形状的修改。结果还表明，如果在数值模型中实现了修改的焊缝几何形状，则同样的SN曲线可以应用于焊接的和磨碎的试样。结果证明，通过在数值模型和ENS方法中应用修改后的焊缝几何形状，可以高精度地预测焊缝（地面）零件的疲劳寿命。根据目前的研究，证明了焊缝几何形状处理方法的优点主要来自于在疲劳临界点处对焊缝几何形状的修改。结果还表明，如果在数值模型中实现了修改的焊缝几何形状，则同样的SN曲线可以应用于焊接的和磨碎的试样。