Prediction of laminate delamination with no iteration

Abstract To simulate laminate delamination using least input parameters and with no iteration is still a challenge. As the laminate is essentially bonded from individual laminae by the matrix, there exists a matrix-layer between two adjacent lamina ones, and a delamination of them must be resulted from a matrix-layer failure. However, a three-dimensional finite element analysis indicates that the stresses of the matrix layer are generally so small that it cannot fail before one of the adjacent laminae assumes a failure. This contradiction suggests that there must be something missing from the elemental stresses of the matrix-layer near the delamination front. We introduce a modifying coefficient (MC) to the matrix-layer stresses, and the modified stresses are checked with a strength-failure criterion. Once a tensile or shear failure is attained, delamination occurs to the adjacent laminae. At any load step, either the layers of an element are completely bonded together or completely separated from each other. No iteration is necessary to identify a delamination in the element. Only an additional critical energy release rate from a DCB test is required. Reasonable correlation between predicted delamination propagations and free-edge delamination initiations and measured counterparts of a number of laminates confirm the efficiency of this work.