Delamination Detection in Mono Composite Leaf Spring by Modal Curvature and Flexibility Approaches

Abstract

The premature failure analysis of laminated composite structures through damage inspections at initial level has gained considerable importance in recent years. Delamination is one of the major failure mechanisms which occur due to low inter-laminar fracture toughness of the matrix in composite structures. Detection of delamination is crucial to ensure safety and reliable use of composites. In the paper, the modal curvature and flexibility methods have been applied for delamination detection in composite leaf spring through analytical and finite element approaches. First, finite element models of healthy and delaminated leaf spring are formulated to evaluate the Eigen value and Eigen vectors. Next, the absolute curvature difference and change in flexibility in both springs are determined after mass normalization. The presence, location and severity of delamination in a spring are found through change in absolute modal curvature and difference in local flexibilities. The modal curvature method precisely identifies the delamination location and its severity than the modal flexibility method.