Effect of Laser Peening with a Microchip Laser on Fatigue Life in Butt-Welded High-Strength Steel

Abstract

Laser peening introduces compressive residual stresses on the surfaces of various materials and is effective in enhancing fatigue strength. Using a small microchip laser, with energies of 5, 10, and 15 mJ, the authors applied laser peening to the base material of an HT780 high-strength steel, and confirmed compressive residual stresses in the near-surface layer. Laser peening with a pulse energy of 15 mJ was then applied to fatigue samples of an HT780 butt-welded joint. It was confirmed that laser peening with the microchip laser prolonged the fatigue life of the welded joint samples to the same level as in previous studies with a conventional laser.

Analysis and Design of Lateral Framing Systems for Multi-Story Steel Buildings

“…During the late 19th and early 20th centuries, engineering development created thin shell and tensile structures of extraordinary refinement and elegance, using the diagrid system with various types, such as the metal, concrete, or wooden beams that are used in the construction of buildings [1]. However, their studies were based on the elastic and plastic behavior of simple rectangular uniform diagonal grids, and the studies tried to find formulas for their collapse loads [2,3]. Due to the rapidly growing population and the scarcity of urban land, the last few decades have required architectures that must consider ways of enabling vertical growth.…”