Experimental study of transverse attachment joints with 40 and 60 mm thick main plates, improved by high-frequency mechanical impact treatment (HFMI)

Journal article, 2018

In recent years, high-frequency mechanical impact (HFMI) treatment has grown in popularity due to its efficiency in improving the fatigue strength of welded joints. The fatigue performance of HFMI-treated welded steel joints has, however, not been thoroughly studied for plate thicknesses above 30 mm. In this study, 40 and 60mm thick main plates with non-load-carrying transverse attachments have been fatigue tested under constant amplitude four-point bending, both in as-welded and HFMI-treated condition to investigate the fatigue performance for large plate thicknesses, typical for weldments in bridges. Axial fatigue strengths were estimated by a modification of the experimental results with fracture mechanics calculations. The main conclusions are that HFMI treatment can result in significant fatigue strength improvement even for large main plate thicknesses and that the difference in fatigue strength between bending and axial loading is negligible for the specimen geometries used in this study.