Tensile behaviour of optimisation-derived additively manufactured single-sided repairs for edge-cracked steel plates

Laser beam directed energy deposition (DED-LB) using wire feedstock, commonly referred to as wire laser additive manufacturing (WLAM), has recently attracted increasing attention as a means of repairing and strengthening damaged steel members. In this study, an experimental investigation was conducted on optimisation-derived additively manufactured single-sided repairs for edge-cracked steel plates. A total of 20 specimens, including intact plates, unrepaired edge-cracked plates and WLAM-repaired plates, were tested under monotonic tension. The as-built characteristics of the repairs were scanned by a 3D optical scanner and analysed in terms of surface morphology, surface roughness, geometric deviations and out-of-plane deformation. The as-built repairs were found to reproduce the intended macroscopic geometry well with non-negligible out-of-plane distortion introduced by the single-sided repair configuration. Four failure modes were identified from the tensile tests, and the load–extension responses demonstrated substantial recovery of the tensile performance of the repaired plates. DIC measurements further showed reduced near-edge strain localisation in the repaired plates relative to the corresponding unrepaired cracked plates at the same applied load. Repair component volume had a pronounced influence on performance recovery, particularly on deformation capacity. The experimental results indicate that the previously proposed semi-elliptical design equations are generally adequate for yield load and maximum load, whereas full recovery of deformation capacity requires additional repair component volume.