DYNAMIC FRACTURE OF WELDED-JOINTS

This paper presents an experimental and analytical investigation of dynamic fracture of T-shaped welded joints (stiffner on a plate) in a high strength steel. A fracture test was designed in which strain rates of several thousand per second can be reached in the weldment region by loading the specimen with tamped explosive. Test conditions can be reliably controlled by adjusting the thickness of the explosive and the density and thickness of the tamping material. The measured initial specimen plate velocity is used as input for finite element simulations of the experiments to calculate the stress and strain and fracture damage histories in the fracture region. Experiments on two specimen sizes were performed to evaluate the effect of geometric scaling of the size on fracture of the weldments. For the two sizes investigated, fracture conditions scaled geometrically. The experimental results were in good agreement with the results of an analysis that used a rate independent, statically calibrated local fracture model to describe fracture by ductile void growth. This agreement suggests that fracture damage in weldments of this particular steel is not very rate sensitive.