TY - CONF
A1 - Rjelka, Marek
A1 - Köhler, Bernd
A1 - Mayer, Andreas
T1 - Extraction of Depth Profiles of Third-Order Elastic Constants in Cracked Media
T2 - AIP Conference Proceedings 1806
N2 - Elastic constants of components are usually determined by tensile tests in combination with ultrasonic
experiments. However, these properties may change due to e.g. mechanical treatments or service conditions during
their lifetime. Knowledge of the actual material parameters is key to the determination of quantities like residual
stresses present in the medium. In this work the acoustic nonlinearity parameter (ANP) for surface acoustic waves is
examined through the derivation of an evolution equation for the amplitude of the second harmonic. Given a certain
depth profile of the third-order elastic constants, the dependence of the ANP with respect to the input frequency is
determined and on the basis of these results, an appropriate inversion method is developed. This method is intended
for the extraction of the depth dependence of the third-order elastic constants of the material from second-harmonic
generation and guided wave mixing experiments, assuming that the change in the linear Rayleigh wave velocity is
small. The latter assumption is supported by a 3D-FEM model study of a medium with randomly distributed microcracks as well as theoretical works on this topic in the literature.
Y1 - 2017
UR - https://opus.hs-offenburg.de/frontdoor/index/index/docId/2666
SP - 060001-1
EP - 060001-9
ER -