A DOUBLE-PLATE FINITE-ELEMENT MODEL FOR THE IMPACT-INDUCED DELAMINATION PROBLEM

A double-plate model is proposed to simulate a composite laminate with impact-induced delamination. Mindlin plate finite elements with large deflection have been employed to calculate stress and strain fields. On the basis of the modified crack closure method, a general expressio n for the strain energy release rate at the delamination front is deri ved. The proposed model was first evaluated by using an isotropic doub le cantilever beam. It is shown that this model is simple and computat ionally efficient. Subsequently, the present model was employed to pre dict impact-induced delamination in composite laminates and was compar ed with experimental results. The effect of shear cracks in the lamina adjacent to the delamination is discussed. The similarities between d elaminations produced by different impact loads is identified and inve stigated by the use of the double-plate model.