Fracture Evaluation and Design Tool for Welded Aluminum Ship Structures Subjected to Impulsive Dynamic Loading

A software tool for fracture evaluation and load deflection prediction of welded aluminum ship structures subjected to impulsive loading will be developed by enhancing and integrating an existing extended finite element method (XFEM) for dynamic fracture of thin shells in Abaqus. The software package will be able to model arbitrary crack paths as dictated by the physics of the scenario, completely independent of the mesh. This will be accomplished by adding discontinuous displacement and velocity fields arbitrarily within the shell elements via two superposed elements with a set of phantom degrees of freedoms. Explicit time integration with one point quadrature scheme and an hourglass control will be implemented to further simplify the treatment of cracked elements and provide consistent history variables for nonlinear material models. A modified Johnson-Cook model coupled with a nonlocal fracture criterion will be implemented to capture an anisotropic and rate dependent nonlinear material behavior and its associated damage initiation. Global Engineering and Materials, Inc. (GEM) has secured commitments for technical support from the University of Texas at El Paso (UTEP) and Professor Ted Belytschko from Northwestern University (NWU). Dr. Belytschko will provide GEM his stand alone explicit dynamic XFEM tool for shells.