Analytical analysis of multi-delaminated laminates under extension using a layerwise stress model

The objective of this work is to provide an accurate and efficient alternative to three-dimensional finite element method (3D-FEM) for the analysis of delaminated laminates with free-edges. In the present study, the application of a layerwise stress model, called the LS1 model, is extended to delaminated multilayered plates subjected to uniaxial extension. The analytical LS1 solutions for a general multilayered plate with arbitrary delaminations in its section are derived. In order to validate the proposed method, (±0)s composite laminates in delaminated state are investigated and results of the LS1 model are compared to 3D-FE solutions. The comparisons in terms of interlaminar stress and energy release rate estimations between the LS1 and 3D-FE models reveal an excellent agreement in non-delaminated and delaminated states. It is concluded that the proposed model, as an accurate and very efficient model for the analysis of delaminations in multilayered plates under extension, can be used in delamination problems using stress based or energy release rate based criteria.