Novel Element for Fracture Analysis of Delaminated Layered Composite Plates Using the Multilayer Modeling Method

A novel element is proposed for fracture analysis of layered composite plates with delamination using the multilayer modeling method. The upper and lower subplates are both divided into one or multiple sublayers, which are modeled by the proposed novel plate element. In particular, the proposed plate element has only the translational degrees of freedom (DOFs), and both the cracked and uncracked portions of delaminated plates are thus easily and naturally modeled. By comparing the DOFs, it is found that the present novel plate element exhibits equivalency to the conventional first-order shear deformable plate element. The element stiffness matrix is derived by the principle of minimum potential energy. To illustrate the applicability of multilayer modeling method, fracture analysis of laminated composites made of either isotropic or orthotropic materials is conducted, of which the total energy release rate (ERR) and its components are calculated using the virtual crack closure technique and compared with those of three-dimensional finite element analyses focusing on the effect of the number of sublayers. The results show that the present novel plate element combined with the multilayer modeling method effectively calculates the total ERR and its components across the width of delaminated composite plates with fewer elements without introducing the interface continuity condition in comparison with the conventional modeling method.