Delamination assessment of a laminated composite beam using distributed piezoelectric sensor/actuator

摘要

This paper focuses on delamination detection of laminated beams using electromechanical impedance (EMI) signatures, which are directly related to the mechanical impedance of the structure. An accurate model of the laminated beam including a delamination introduced inside as well as installed PZT transducers is established. In the model, we consider the dynamic behavior of the piezoelectric patches as well as the presence of bonding imperfection using a Kelvin-type viscoelastic interface. In order to develop the recursive formulations to reduce the size of the final equations in the method of reverberation-ray matrix (MRRM), new local scattering relations are established for this smart beam with distributed piezoelectric patches and delaminated members. Then, an analytical expression of the impedance, which involves information on the size and position of the delamination in the smart beam, is derived based on the improved MRRM via the recursive formulations. Comparison with existing experimental and numerical results is made to validate the proposed analysis. The numerical simulations allow us to study more closely the influence of some physical parameters, such as transducer size and position, on the EMI signatures. Moreover, the covariance, a kind of non-parametric damage index, integrated with distributed sensor/actuators is also employed to identify the delamination in the laminate.