Damage Modeling and Detection in Smart Composites

The presence of damage in structures made out of composite and/or piezoelectric materials can cause significant degradation in structural performance. In the present paper, damage indices based on two-dimensional gapped smoothing technique and model strains are developed in order to enhance the accuracy in predicting the location and extent of damage in composite structures. Structural analysis is performed based on a refined higher order theory, which can capture the transverse shear effects in anisotropic laminates. An approach using the developed damage indices and the laminate model of the higher order theory is employed to model and identify delaminations in composite laminates. It is also used in the delamination analysis of composite laminates with piezoelectric actuators. The proposed modal strain based damage indexes are used to perform delamination analysis. Comparison study is performed to illustrate that the reliability and robustness of the new proposed damage indices in locating delaminations in composite and smart composite structures. The effects on modal strain and damage indices due to the presence of surface bounded piezoelectric actuators are also presented and discussed.