Article
Inverse identification of structural and material parameters using elastic guided waves (en)
* Presenting author
Abstract:
Elastic guided waves offer several advantages for the nondestructive evaluation and characterization of complex materials. Their dispersive and multimodal nature is particularly attractive, for instance when it is desirable to use wavelengths larger than the sample thickness or when it is necessary to identify anisotropic elastic properties. Dispersion curves reflect the dependence of the phase velocities with the frequency and thus allow inferring effective properties of the waveguide (e.g., anisotropic elasticity tensor, thickness, porosity) by fitting a waveguide model to the experimental data (i.e., solving an inverse problem). In this talk, I will present an overview of recent advances for the characterization of complex media using elastic guided waves, e.g., anisotropic materials, bonded structures, and nanoporous silicon membranes. Two experimental approaches for measuring multimode dispersion curves will be described. The first one takes advantage of the advent of multi-element probes driven by multichannel electronics, whereas the second one relies on the use of non-contact laser ultrasonics. Associated modeling aspects, along with the inverse procedure for identifying the model parameters, will subsequently be introduced. Lastly, I will discuss how generalized continuum models typically used for describing architectured media could benefit from this approach for retrieving the constitutive parameters of interest.