New kinematical constraints of cracked MITC4 shell elements based on the phantom-node method for fracture analysis

In this paper, the phantom-node method is developed for cracked plates and shells simulated by continuum mechanics based 4-node quadrilateral shell elements using the mixed interpolation of tensorial components (MITC) technique for the shear-locking removal. The proposed method permits an arbitrary crack to cut through elements. The discontinuity across the crack is described by continuous displacement fields of overlapping elements that are constructed by duplicating homologous nodes and realized on the real parts of the cracked elements. New kinematical constraints for the nodal displacements of the overlapping triple elements are derived to represent the displacement fields of the partially cracked elements. The interaction domain integral of cracked shell structures is formulated to extract the fracture parameters. Several numerical benchmark cracked plates and shells are analyzed to evaluate the accuracy and robustness of the proposed method.