On the calculation of stress intensity factors for surface cracks in welded pipe-plate and tubular joints

It is common practice to calculate stress intensity factors for surface cracks in pipe-plate/tubular joints using stress intensity factor solutions developed for surface cracks in T-plate joints or flat plates with magnification factors. However, since these solutions cannot account for stress redistribution resulting from the reduction of member stiffness with crack growth, load shedding models have been introduced to modify these solutions. In the present work, a new method for the calculation of stress intensity factors for surface cracks in pipe-plate and tubular joints is developed. It is based on a model of T-plate weld joints with built-in ends and, therefore, accommodates load shedding effects directly. The method for the calculation of stress intensity factors for surface cracks in T-plate joints with built-in ends under arbitrary mode I loads using the weight function method is presented first. Then, applications of the T-plate joint with built-in ends model to calculate the stress intensity factors for surface cracks in pipe-plate and tubular T-joints are demonstrated. It is shown that the current model accounts for the load shedding effects directly and provides stress intensity factor solutions for surface cracks in pipe-plate and tubular joints accurately. (C) 2002 Elsevier Science Ltd. All rights reserved.