Delamination buckling for laminated composite structures with curvature

Abstract

Finite element analysis is employed to find the deformation behaviors for delamination buckling of laminated composite panels with curvature. For the present study, two models are considered ; one is a short laminated orthotropic tube, which is assumed to undergo axisymmetric buckling deformation under uniform axial compression due to its short axial length, the other is a curved composite panel undergoing a fully three-dimensional deformation under axial compression. Delamination is assumed to exist prior to loading, and it spans the entire circumference. Both of the two models are subjected to axial loading in the form of uniform applied displacement. On the basis of a total Lagrangian approach, non-linear finite element analysis is formulated with emphasis on finding non-linear post-buckling behavior. Solution procedure for treating the frictionless contact of delamination crack faces for a short orthotropic tube via nonlinear finite element method is treated with the aid of the well-known quadratic programming procedure described by the incremental potential energy and impenetrable constraint of delamination crack faces. To treat the three-dimensional frictionless contact for a curved composite panel, the Lagrange multiplier method is introduced and an algorithm of nodes to surface contact is employed. Furthermore, to calculate energy release rate at the tip of delamination the path independent J-integral is formulated for a three-dimensional case and for an axisymmetric case in the context of finite deformation. The numerical results obtained from non-linear finite element method show an inherently built-in crack arrest mechanism for the short orthotropic laminated tube. For the laminated composite panel with curvature, no bifurcation phenomena are observed due to the effect of curvature, and the localized high energy release rate may lead to non-uniform growth of the crack front.