Damage Detection for Laminated Composite Structures with Wavelet Analysis

摘要

During the service of composite material structures, crack or delamination in their key components will continuously accumulate, and finally lead to a sudden increase of structural damage. This will result in an abrupt reduction of local stiffness of composite material structures and perturbations to the structural dynamic responses. Using piezoelectric patches bounded or embedded in composite material structures as actuators and sensors, the system for exciting the structure and sensing its dynamic response can be established. Extracting damage information from the response and monitoring the perturbations of structural dynamics can be implemented by using wavelet analysis. This will conduce to the capture of the accurate time of damage occurrence. Making use of piezoelectric intelligence material, continuous harmonic excitation and wavelet analysis technology, we can build online damage detection and health monitor system. The numerical simulation signify that we can gain the moment composite material laminated beam appears local sudden damage by wavelet decomposition signal of acceleration response signal. Although structure local rigidity decline 1% only, it can gain obvious strange change by acceleration response wavelet decomposition signals. The method developed in this paper can help build the system of online damage detection and health monitoring of composite material structures when they cannot be directly observed or measured.