A simplified approach to the damage tolerance design of asymmetric tapered laminates. Part I: Methodology development

Tapered composite laminates are susceptible to interlaminar damage in the form of delaminations growing from ply drop-off locations. This study presents an analytical method for the calculation of the energy release rates associated with interlaminar cracks emanating from the ply termination in both the laminate thick and thin sections, also accounting for the effects of the tapering angle. The proposed approach is based on modeling asymmetrically tapered composite laminates as assemblies of layered Euler–Bernoulli beam segments; these are split and reconnected through-the-thickness at the ply-drop-off location. The presence of a local resin pocket is explicitly considered in the model. Orthotropic rescaling is employed in order to take into account the material behavior through-the-thickness. This paper presents the analytical formulation of the proposed approach, whose validation follows in part II.