Delamination damage identification in composite shell structures based on inverse finite element method and refined zigzag theory

Official URL: https://dx.doi.org/10.1201/9781003230373-41

The inverse finite element method (iFEM) is a viable and well-known shape-sensing method developed for continuous real-time monitoring of engineering structures by using only strain gauge measurements collected from discrete positions of the structure. In this paper, a novel damage-detection strategy for composite and sandwich shell structures is developed using a computational algorithm based on the iFEM coupled with a state-of-the-art single-layer theory, refined zigzag theory (RZT). The new strategy uses only strain gauge measurements taken from the on-board sensors to predict the size and location of delamination damage. Initially, the in-plane location and delamination size are identified. Subsequently, through-the-thickness locations are identified by examining the influence of the zigzag kinematics on the strain response of the laminated structure. The fundamental advantage of this computational approach is that it does not require any a priori knowledge of loading conditions, and it is also applicable to a general class of laminated composite and sandwich structures. The applicability of the new damage detection strategy is examined for various structural models with a delaminated region, and the damage prediction accuracy of iFEM-RZT is proved through comprehensive comparative study of results.