Software application for evaluating interfacial stresses in inelastic symmetrical laminates with free edges

Authors propose herein a software application called DEILAM, which is able to evaluate the free edge effects in multilayered inelastic structures that essentially bear tensile loads. The inelastic behavior of both layers and interfaces are take into account. The program therefore involves inelastic strain fields in the layers and fields of displacement discontinuities at the interfaces. These inelastic fields, such as thermal strains or interface sliding, are assumed to be known by the user. For evaluating the 3D interfacial stresses, the program uses an approximate model that models the laminate by a superposition of Reissner plates coupled by interfacial stresses. Calculations show that no singularities exist for the model even at the edge and results converge quickly. Calculations are validated by comparing the results with finite element calculations and with Pagano’s local model. Analysing the maximum values of the interfacial stresses for some examples, the authors then show how the software can help predict the place where delamination might appear. Since delamination is a critical failure mode that often takes place at free edges, this program with a delamination criterion involving the maximum interfacial stresses can prove to be an important tool in composite structure design.