Publication

Abstract : A refined finite element model and a new post processing subprogram to determine mixed mode membrane and bending stress intensity factors for arbitrarily located and oriented cracks in complex shell type structures is presented. A fine mesh of singular isoparametric triangular shell element (STRIA6) with user specified number NS from one crack face to another and size a is created around each crack-tip. The rest of the domain is discretized using a compatible mesh of regular quadratic isoparametric triangular shell element (TRIA6) and quadratic isoparametric quadrilateral shell element (QUAD8). A new post processing subprogram 3MBSIF is presented to compute the Stress Intensity Factors Posteriori. The proposed Finite Element Model implemented using ABAQUS, a unified FEA software, and the new post processing subprogram 3MBSIF are validated using benchmarks, a set of standard test problems with known target solutions. Selected results of a parametric study are presented for arbitrarily oriented cracks of increasing lengths in the toroidal segment of a cylindrical shell with tori-spherical end closures under internal pressure loading.