@inproceedings{9f3a4e2379214ce9a7fdc63b219b2015,
title = "Effect of skew angle on second harmonic guided wave measurement in composite plates",
abstract = "Waves propagating in anisotropic media are subject to skewing effects due to the media having directional wave speed dependence, which is characterized by slowness curves. Likewise, the generation of second harmonics is sensitive to micro-scale damage that is generally not detectable from linear features of ultrasonic waves. Here, the effect of skew angle on second harmonic guided wave measurement in a transversely isotropic lamina and a quasi-isotropic laminate are numerically studied. The strain energy density function for a nonlinear transversely isotropic material is formulated in terms of the Green-Lagrange strain invariants. The guided wave mode pairs for cumulative second harmonic generation in the plate are selected in accordance with the internal resonance criteria-i.e., phase matching and non-zero power flux. Moreover, the skew angle dispersion curves for the mode pairs are obtained from the semi-analytical finite element method using the derivative of the slowness curve. The skew angles of the primary and secondary wave modes are calculated and wave propagation simulations are carried out using COMSOL. Numerical simulations revealed that the effect of skew angle mismatch can be significant for second harmonic generation in anisotropic media. The importance of skew angle matching on cumulative second harmonic generation is emphasized and the accompanying issue of the selection of internally resonant mode pairs for both a unidirectional transversely isotropic lamina and a quasi-isotropic laminate is demonstrated.",
author = "Hwanjeong Cho and Sungho Choi and Lissenden, {Cliff J.}",
note = "Funding Information: This research was conducted with advanced cyberinfrastructure computational resources provided by the Institute for CyberScience at The Pennsylvania State University. The authors also acknowledge the discussions with Jinling Zhao in the Nanjing University of Aeronautics and Astronautics. Publisher Copyright: {\textcopyright} 2017 Author(s).; 43rd Annual Review of Progress in Quantitative Nondestructive Evaluation, QNDE 2016 ; Conference date: 17-07-2016 Through 22-07-2016",
year = "2017",
month = feb,
day = "16",
doi = "10.1063/1.4974611",
language = "English (US)",
series = "AIP Conference Proceedings",
publisher = "American Institute of Physics Inc.",
editor = "Bond, {Leonard J.} and Chimenti, {Dale E.}",
booktitle = "43rd Annual Review of Progress in Quantitative Nondestructive Evaluation, Volume 36",
}