Delamination detection in laminated composite beams using electro-mechanical impedance signatures

This paper focuses on the delamination detection in composite beams using electro-mechanical impedance (EMI) signatures, which is directly related to the structure's mechanical impedance. A model of a laminated beam including a delamination as well as installed PZT transducers is presented. Furthermore, the model has to take into account the dynamic behavior of the piezoelectric patches and simulate the presence of the imperfect bonding between the PZT patch and the host laminate based on a classic shear lag law. Then, an analytical expression of impedance involving information on the size and the position of a delamination in this coupled smart structure system is derived via the reverberation matrix method (RMM). Comparison with existent experimental and numerical results is presented to validate the present analysis. The numerical simulations allow us to study more closely the influence of some geometrical parameters such as sensor size and position. The analysis in this paper provides necessary theoretical basis for delamination detection in composite structures.