Curvature Shape Based Impact Damage Detection in Composite Laminates

In this study a vibration-based damage detection method-2D GSM (Two-Dimensional Gapped Smoothing Method), for plate-like structure is presented. A kind of typical carbon fibre reinforced composite laminate is studied as a quasi-isotropic and quasi-homogeneous material. The impact damage was produced by a drop weight acting on the surface of unidirectional tensile stressed composite laminate. For the delamination detaction of laminate by 2D GSM, PZT patches were arranged as actuators to excite the torsion mode of laminate under a certain frequency. By changing the frequency and the phase of signal inputted into each patch, we can actuate the laminate into different operational deflection shapes (ODSs). The deflection shapes of laminate are measured by a Scanning Laser Doppler Vibrometer (SLDV) system. A curvature shape based Two Dimensional Gapped Smoothing Method (2D GSM) is proposed and applied to locate the delamination of laminate caused by impact. The result shows that the 2D GSM is an efficient way for the damage detection in composite laminates.