COMPARISON OF ANALYTICAL, NUMERICAL AND EXPERIMENTAL SOLUTIONS TO PROBLEMS OF DEEPLY CRACKED WELDED JOINTS IN BENDING

This paper presents analytical and numerical solutions to the analysis of welded specimens when loaded in three‐point bending, and compares the results with those obtained experimentally. In each case the crack is located within the weld material, and runs parallel to the weld. Two analytical models are presented for deriving limit loads using slip‐line field theory. Due to the welding process, the material behaviour in the weld‐base interface is complex, and this is described in the analytical solutions using a number of material zones. The analytical solutions also provide the η and d∞ coefficients which are used to determine the J and crack tip opening displacement (CTOD) parameters. These solutions are then compared with numerical results obtained using the finite element method. Good agreement is obtained between the numerical and analytical results, and it is shown that for overmatched specimens a better analytical solution can be obtained by using a slip‐line field geometry which passes predominantly through the base material. When the analytical η solutions are applied to the experimental results it is shown that, in the case of undermatched weldments, J can be used as a fracture characterising parameter, but it cannot be used in the case of an overmatched specimen.