A Phantom-Node Method for Predicting Residual Strength in Shell Structures with a Single Crack Based on a Crack Tip Opening Angle Criterion

This paper develops a phantom-node method for MITC 3-node shell element. According to the phantomnode method, overlapping paired elements are used to represent an element cut through by a crack. In which, each element is created by extending a part of the cracked element to a phantom domain until it becomes a completely standard finite element. As a result, separate assumption for transverse shear strain of the MITC 3-node element to remove “shear locking” is employed straightforwardly. The development describes the crack in both thin and thick shell structures and is no need to remesh as the crack propagates. The method is applied to numerically simulate a fracture test of an internally pressurized cylindrical shell conducted by (Keesecker et al. 2003). Material constitutive law follows the J2-plasticity with linear isotropic hardening and the small strain assumption. The crack tip opening angle (CTOA) criterion, one of the fracture criteria, characterizes the crack growth condition. A predicted crack growth curve of pressure versus half-crack length is comparable to experimental measurements and other numerical results.