Three-dimensional fatigue crack propagation analysis of welded steel beam based on global-local numerical model

Abstract

The existing fatigue assessment approaches were mainly conducted on the component level. The interaction of local component damage and the global response cannot be well addressed. In this study, three-dimensional (3D) fatigue crack propagation analysis approach based on global-local numerical model was implemented, and examined to be accurate and effective through a series of systematic experimental data obtained by Fisher. Afterwards, the approach was introduced into a typical steel truss bridge for realizing more refined fatigue assessment from the global structural level. The fatigue performance of the longitudinal steel welded beam in the steel truss bridge was investigated based on global-local model and local model respectively. It was found that there is no difference in terms of the fatigue crack growth mechanism between the simulation between global-local model and local model due to that the stress level of the whole structure is relatively low. At last, the effect of heavy haul train operation on the fatigue performance of the steel truss bridge was analyzed. It was observed that the residual life of the longitudinal steel welded beam would have an obvious reduction when the axle load was increasing. The research work in this study presents a technical solution for the fatigue assessment of the global structure and can provide beneficial reference for relevant practical engineering projects.

Residual Stress and Fatigue Strength Analysis of Stiffener Welds of Steel-Plate Composite Girder Bridge Considering Welding Sequence

“…Such non-load-bearing components can create unexpected fatigue problems due to welding residual stresses. Among them, the weld cracking at the connection between the stiffener and the roof is an atypical cyclic pressure fatigue cracking problem [5][6][7], as shown in Figure 1. This kind of disease is especially prevalent in steel-plate composite girder bridges with a small girder system that has been vigorously promoted by Japan and China [8][9][10].…”