Numerical modelling: delamination buckling

Abstract

Laminates can be sensitive to delamination buckling, which occurs when a partially delaminated panel is subjected to a compressive load. The interaction of local buckling and extension of the delaminated zone typically results in a decrease of the residual strength and, eventually, in a collapse of the structure. Fortunately, this phenomenon has never been observed in experimental tests with Glare. Although the delaminated layers buckle locally, the delamination front does not propagate within the range of compressive stresses that can be expected in typical aerospace structures.

Numerical analyses can give more insight into the mechanisms that prevent Glare panels from collapsing. In this paper, some experimental observations regarding delamination in Glare are discussed and, based on these observations, a numerical model is constructed at a meso-mechanical level. In this approach, solid-like shell elements are used to model the individual layers. They are connected by interface elements, which are capable of modelling delamination between the layers. These numerical techniques are used to simulate two classical delamination-buckling tests of a Glare laminate.