Fatigue-strength assessment of laser welds in corrugated core steel sandwich panels

Abstract

The work presented in this paper addresses the topic of fatigue in laser stake-welds that join the constituent plates in corrugated core steel sandwich panels for bridge application. In order to investigate the fatigue strength of the stake-welds, and furthermore the panel joints, numerical analyses and experimental tests have been conducted for specimens of “cell”- and “panel”-types. Load-cases that produce joint-deformations of the smaller cell-specimens were adopted to reflect the deformation of full-scale panel joints. The investigations regard both conventional structural C-Mn and stainless steel materials. In addition to the common mode of crack propagation through the weld itself, a mode of cracking that initiates at the stake-weld root and propagates through the base plate was observed in the experiments. Regardless of the type of crack-mode, the results of this paper show that the fatigue-strength given in current recommendations, based on the effective notch stress as the fatigue parameter, can be used for fatigue design of laser-welded bridge decks. In addition to the fatigue tests on the smaller scale cell-specimens, a larger scale panel was tested where the results proof the concept of using laser-welded corrugated core steel sandwich panels for bridge application, with respect to fatigue performance.