The effect of High-Frequency Mechanical Impact (HFMI) treatment on the fatigue resistance of structural steel S355 butt welds with macro geometric imperfections outside of the usual fatigue design limits was investigated. Thin-walled specimens (t = 8 mm) were manufactured with different degrees of angular and linear misalignment and fatigue tested in the as welded and HFMI treated condition. The fatigue test results show that HFMI treatment can compensate the fatigue strength-reducing effects of macro geometric imperfections (Δσ_C,HFMI = 127 N/mm², m = 5), but also that linear and angular misalignment does not reduce the fatigue strength of butt welds as severely as rules and guidelines suggest (Δσ_C,AW = 107 N/mm², m = 3). Underestimating the fatigue strength determined by testing by more than 40%, numerical analysis and strain gauge measurements show that the application of the effective notch stress approach and the structural hot-spot stress approach delivers conservative assessment results, which might not always be representative for the actual fatigue strength benefit that can be gained by HFMI treatment.

研究了高频机械冲击 (HFMI) 处理对具有超出通常疲劳设计极限的宏观几何缺陷的结构钢 S355 对接焊缝的抗疲劳性的影响。薄壁样品 ( t = 8 mm) 的制造具有不同程度的角度和线性不对中，并在焊接和 HFMI 处理条件下进行疲劳测试。疲劳试验结果表明，HFMI处理可以补偿宏观几何缺陷（ ΔσC _，HFMI = 127 N/mm ²，m = 5）的疲劳强度降低效应，但线性和角度不对中并不能降低疲劳强度。对接焊缝的强度严格按照规则和指南的建议（Δ σ _C,AW = 107 N/mm ² , m = 3）。数值分析和应变仪测量表明，有效缺口应力法和结构热点应力法的应用给出了保守的评估结果，低估了通过测试确定的疲劳强度超过 40%，这可能并不总是能够代表实际情况。通过 HFMI 治疗可以获得的实际疲劳强度益处。