Detection of damage in laminated composite structures using transverse shear mode

This work focuses on actively detecting damage in laminated composite structures in transverse shear mode. A 3D model of a laminated composite beam, instrumented with a piezoelectric patch (PZT) polarized in transverse shear mode along its length, is created and analyzed under various mechanical and electrical boundary conditions and for different vibration modes. Damage detection indicators for two types of laminated composite beams, presence of a crack or delamination, are processed and evaluated using parametric finite element analyses. The results indicate that the frequency-change factors FCF and FCF(2 )are effective indicators of damage in laminated composite beams, with FCF2 being the most effective. The mechanical boundary conditions have an impact on the values of the frequency-change factors, while electrical boundary conditions have little effect. It is found that also, open-circuit frequency-based damage indicators' performances are similar to short-circuit ones. The obtained results can be further used, for example, for training artificial neural networks for the quantification of the analyzed damage types.