Dynamic behaviors of butt welds and fillet welds under intermediate strain rate

Abstract

Dynamic properties of widely used butt welds and fillet welds would affect the behavior of welded joints in steel structures under dynamic loading. In the open literature, there are very limited studies on the behavior of butt welds and fillet welds under dynamic loads, such as impact and blast. In this study, a compression-tension conversion experimental facility was specifically designed for dynamic testing of butt welds and fillet welds at intermediate strain rates. The steel plate (SP), butt weld (BW), tensile fillet weld (TFW), and shear fillet weld (SFW) at different strain rates were tested. The corresponding quasi-static tests were also performed for comparison. The strength, failure mode, and fracture strain of the BW, TFW and SFW under static and dynamic loads were compared and analyzed. The effects of weld strength matching or overmatching on butt welds and fillet welds were also investigated. The results showed that with the increase in strain rate, the strength of the BW, TFW, and SFW increase; the fracture strain of the BW also increases but those of the TFW and SFW decrease. The failure modes of the BW and TFW were significantly influenced by the weld strength matching, whilst that of the SFW was less affected. Two empirical formulae were proposed to predict the dynamic strength of different steel materials and butt welds as well as fillet welds.