Abstract
The increasing use of composites and composite laminates requires extensive efforts in developing NDE methods for these sophisticated materials. The main problem, especially with respect to algorithmic imaging, arises from their anisotropic nature which causes the splitting of phase-and group velocity directions. Therefore the inverse scattering theory established for acoustic [1] or isotropic materials [2] does not sufficiently describe wave propagation and imaging in composites. In layered structures additional difficulties are associated with multiple reflection and transmission. Hence, for transversely-isotropic materials such as fiber-reinforced composites, we first discuss plane wave solutions of the elastodynamic equation of motion yielding slowness-and group velocity diagrams, using a coordinate-free approach as given in [3] for the electromagnetic case and in [4] for the isotropic case. The propagation of Gaussian wave packets in unidirectional homogeneous and layered structures is then calculated for arbitrary layer orientations; the results are shown as time domain wavefront snapshots. Finally, an integral representation of Green’s functions for the transversely-isotropic medium is given via spatial Fourier-transforms, being particularly convenient to provide the basis for imaging in terms of Diffraction Tomography [1]. All results are given for arbitrary fiber direction.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
K.J. Langenberg: Introduction to the Special Issue on Inverse Problems. Wave Motion. 11 (1989) 99–112
K.J. Langenberg, T. Kreutter, K. Mayer, P. Fellinger: Inverse Scattering and Imaging. Proc. of the IUTAM Symposium, Boulder, CO, 1989. North-Holland,Amsterdam (1990)
H.C. Chen: Theory of Electromagnetic Waves - A Coordinate-Free Approach. McGraw Hill, New York (1983)
P. Fellinger: Ph.D. Thesis, University of Kassel, FRG (1991)
Y.H. Pao, V. Varatliarajulu: Huygens’ Principle, Radiation Conditions and Integral Formulas for the Scattering of Elastic Waves. J.Acoust.Soc.Am., 59 (1976) 1361–1371
J.H.M.T van der Hijden: Propagation of Transient Elastic Waves in Stratified Anisotropic Media. North-Holland, Amsterdam (1987)
M. Spies: Ph.D. Thesis, Universität des Saarlandes, Saarbrücken, FRG (in preparation)
A.N. Norris: A Theory of Pulse Propagation in Elastic Anisotropic Solids. Wave Motion, 9 (1987) 509–532
J.E. Zimmer, J.R. Cost: Determination of the Elastic Constants of a Unidirectional Fiber Composite using Ultrasonic Velocity Measurements. J.Acoust.Soc.Am., 47 (1970) 795–803
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1992 Springer Science+Business Media New York
About this chapter
Cite this chapter
Spies, M., Fellinger, P., Langenberg, K.J. (1992). Elastic Waves in Homogeneous and Layered Transversely-Isotropic Media: Gaussian Wave Packets and Green Functions. In: Thompson, D.O., Chimenti, D.E. (eds) Review of Progress in Quantitative Nondestructive Evaluation. Advances in Cryogenic Engineering, vol 28. Springer, Boston, MA. https://doi.org/10.1007/978-1-4615-3344-3_22
Download citation
DOI: https://doi.org/10.1007/978-1-4615-3344-3_22
Publisher Name: Springer, Boston, MA
Print ISBN: 978-1-4613-6474-0
Online ISBN: 978-1-4615-3344-3
eBook Packages: Springer Book Archive