Application of the boundary shape perturbation method to stress analysis of laminated composites with ply waviness

Abstract

Ply waviness is a manufacturing defect that occurs in thick fibre-reinforced composite laminates during the curing process. It is known to cause significant degradation of mechanical properties and fatigue life, particularly under compressive loading. To predict failure in the vicinity of the wavy layer, accurate information about stresses at the undulating interfaces is needed. In this paper, an analytical approach to determination of stresses in laminated composites with ply waviness subjected to compressive or flexural loading is presented. Using the boundary shape perturbation method, 3D elasticity problem for a laminate with undulating interfaces is transformed into a sequence of 3D elasticity problems for a reference laminate with perfectly flat layers. The application of the presented analytical approach to a particular problem is illustrated with the example of a transversally loaded laminated plate with a wavy layer.