Damage characterization in waveguides with ultrasonic shear waves

Damage can be viewed as a continuum discontinuity. In order to identify and quantify damage, the present study investigates the dependence of reflection and transmission coefficients from a discontinuity in a waveguide using a finite element model. A parametric study of a fiber reinforced polymer laminate beam is presented with five different ratios of reduced cross-section with two different kinds of geometry: symmetric and asymmetric, in three discontinuity lengths. What is more, finite element results are compared with the corresponding results of a semi- analytical model based on the principle of reciprocity in elastodynamics. The analysis shows that: a) depending on the kind of discontinuity, the diagnostic potential of the used guided wave depends on the mode existence and on the magnitude of its wavelength in relation to the discontinuity extension, b) reflection and transmission coefficients can be used to identify and characterize damage both in symmetrical and asymmetrical damaged cross sections.