Delaying Effect of Fatigue Crack Propagation by Single-Pulse Laser Irradiation

In this study, a single-pulse laser technique was applied to repair the cracked plate. The idea of this technique is based on delaying fatigue crack propagation by irradiating the area ahead of the crack tip by using a single-pulse laser with a high power of 1500 W. In order to verify the capability of this technique, fatigue tests were conducted on specimens with a hole on the center to induce fatigue cracks at the edge of the hole. A single-pulse laser irradiation was then applied ahead of this natural crack tip, and fatigue tests were subsequently conducted. The fatigue crack propagation behavior was monitored during cycling loading by using a digital microscope. It was confirmed that the crack irradiated by a pulse-laser is not almost progressed or is deflected around the irradiated area in subsequent cyclic loading after the repairing treatment, which means that the pulse laser technique could be located as an alternative to existing repairing techniques