Nonlinear Analysis of Damaged Metal-Based Composite Plates Using Guided Waves

Resonance experiments have already proved the high level of nonlinearity in complex materials, including micro-cracked composites. However, the nonlinear parameters related to elastic modulus and damping are defined around a given resonance mode and are therefore known over a very limited frequency domain. In this contribution, the nonlinear parameters are determined on intact and damaged metal-based composite plates for several flexural resonances. Furthermore, the use of the theoretical formalism corresponding to guided flexural waves allowed to define a nonlinear parameter over a larger frequency domain. Finally, the nonlinear convolution method allowed to take advantage of the harmonics related to the different resonance modes in order to define new non-linear parameters whose sensitivity is much greater than the ones determined at the fundamental frequencies.