Being able to handle wave propagation is essential to the understanding of nondestructive evaluation techniques, which enable location and measurement of defects in structures, evaluation of constitutive material constants, and identification of the state of stress. This short course covers selected problems of wave propagation in structures, that is, waves in strings, bulk waves in 3D solids, guided waves, acoustoelasticity, and their application to the solution of materials characterization and image reconstruction problems.
July 12-14-15, 2022 at 3:00pm-5:00pm
Tuesday July 12, 2022, 3:00pm-5:00pm
Dispersion principles; bulk waves in unbounded isotropic and anisotropic classical continua; the acoustic tensor. Cube-cutting technique for the experimental evaluation of material constants. Reflection and transmission of waves from interfaces.
Thursday July 14, 2022, 3:00pm-5:00pm
Propagation of bulk waves in Cosserat and Second-gradient continua. Guided waves in plates: shear and Rayleigh-Lamb waves. Semi-analytical methods for the calculus of dispersion curves in waveguides. Waves in bars and beams: standing waves and global modes of vibration, spectral elements.
Friday July 15, 2022, 3:00pm-5:00pm
Wave propagation in a prestressed medium: the theory of acoustoelasticity. Nonlinear effects: the arising of higher harmonics in internal resonance conditions. Application of beamformers and projection techniques (Radon transform) to defect/inclusion image reconstruction and to the identification of the state of stress.