Assessment of multiple flat elliptical cracks with interactions

The failure of aging aircraft, pressure vessels and many welded structures is frequently due to elliptical cracks, which arise due to in service operation or the initial fabrication processes. Cracks have the potential to interact. Determination of the residual strength of structure requires an accurate knowledge of the stress intensity factor distribution around the crack front. When interacting cracks prevail, the lack of interaction effect in among multiple cracks may lead to an inadequate evaluation. A hybrid formulation capable of representing stiffness change is developed. This enables the accurate analysis of multiple load path structures containing multiple three dimensional cracks. This procedure complement the standard finite element alternating technique. (C) 2002 Published by Elsevier Science Ltd.