Improved vibration based damage detection in laminated composite plate structures under free and forced modal analysis

Abstract

Composite materials are widely used in modern structural design and technologies due to their qualified mechanical properties and high stiffness to weight ratio. Fibre breakage (FB) and delamination (Dlm) are the most serious damages in these materials, which led to stiffness reduction and loose of functionality and followed by catastrophic failure of the overall structure. The current study presents an extended evaluation of a recent proposed damage index to confirm its capability to identify and quantify structural damage in much more moderate conditions. It has used an improved technique to analysis the measured mode shape curvature (MSC) of the first three mode shapes under both free and forced vibrations for identifying damage location in laminated carbon fibre-reinforced polymer (CFRP) plate structures. It has confirmed its best finding for optimally diagnosis the damage severity and suppressing the confusion of noise effects in both theoretical and experimental analyses. The results show that the improved damage index can be employed with higher accuracy when compared with previous studies for detecting the exact damage location within the laminated composite structure.