This paper investigates the fatigue strength enhancement of two types of peening techniques: hammer peening with impact crack-closure retrofit apparatus and high-frequency mechanical impact (HFMI) treatment on out-of-plane gusset-welded joints made of SBHS700. In this work, fatigue tests were continuously carried out using plate specimens that were removed from a previously tested girder specimen. The results showed that the fatigue strength enhancement of these peening techniques on the welded joints was expected to be at least three classes higher compared with as-welded details with similar dimensions. Unexpectedly, the improvement effect of the hammer peening on one specimen was slightly lower than that of the other specimens. According to SEM observation, the cause of the slight reduction was that due to its weld shape, the distance between the crack initiation point and the treatment edge became greater than 2 mm. Finally, evaluations were performed on available data, including the test results from this study, based on an extended Modified Goodman model to estimate the fatigue limits of HFMI-treated joints. Consequently, the estimation results by the model indicated a good agreement with the fatigue strength enhancement of HFMI treatment and a possibility to be able to assess the enhancement of the hammer peening.

本文研究了两种类型的喷丸技术的疲劳强度增强：带冲击裂纹闭合改型设备的锤击喷丸和由SBHS700制成的平面角撑板焊接接头的高频机械冲击（HFMI）处理。在这项工作中，使用从先前测试的大梁样本中取出的板样本连续进行疲劳测试。结果表明，与类似尺寸的焊缝细节相比，这些喷丸技术在焊接接头上的疲劳强度提高至少要高三级。出乎意料的是，锤击强化对一个样品的改善效果略低于其他样品。根据SEM观察，轻微降低的原因是由于其焊接形状，裂纹起始点和处理边缘之间的距离大于2 mm。最后，基于扩展的改良古德曼模型，对可用数据（包括本研究的测试结果）进行评估，以评估HFMI处理过的关节的疲劳极限。因此，该模型的估计结果表明与HFMI处理的疲劳强度增强有很好的一致性，并且有可能评估锤击强化的可能性。