TY  - CHAP
U1  - Konferenzveröffentlichung
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
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
U6  - https://doi.org/10.1063/1.4974610
DO  - https://doi.org/10.1063/1.4974610
VL  - 1806
IS  - 1
SP  - 060001-1
EP  - 060001-9
S1  - 9
ER  -