2D finite element modeling of the non-collinear mixing method for detection and characterization of closed cracks

Abstract

Cite this article as: P. Blanloeuil, A. Meziane, C. Bacon, 2D Finite Element modeling of the non-collinear mixing method for detection and characterization of closed cracks, NDT&E International, http://dx.doi.org/10.1016/j. ndteint. 2015.08.001 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractThe non-collinear mixing technique is applied for detection and characterization of closed cracks.The method is based on the nonlinear interaction of two shear waves generated with an oblique incidence, which leads to the scattering of a longitudinal wave. A Finite Element model is used to demonstrate its application to a closed crack. Contact acoustic nonlinearity is modeled using unilateral contact law with Coulomb's friction. The method is shown to be effective and promising when applied to a closed crack. Scattering of the longitudinal wave also enables us to image the crack, giving its position and size.

Nonlinear Coda Wave Interferometry: Sensitivity to wave-induced material property changes analyzed via numerical simulations in 2D

“…The cracking performed in the experimental study [21] is in fact not a controlled process, and the resulting cracks do display a high degree of randomness (shape, size, orientation, etc.). Moreover, it can be expected that for a crack with wavy surfaces [30], the clapping and stickslip processes generated by pump waves are involved in the nonlinear mixing of coda waves [31,32]. Depending on the pump wave amplitude, some parts of the cracks can stay open, and the presence of cracks generates both linear scattering and nonlinear mixing of coda waves.…”

Analytical extension of Finite Element solution for computing the nonlinear far field of ultrasonic waves scattered by a closed crack

“…More recently, the scattered wave has been used to evaluate plastic deformation in an aluminum solid [15]. The method has also been successfully applied to the evaluation of physical aging of PVC [16], the evaluation of a diffusion welding interface in titanium [17], and more recently to imperfect interfaces [31] and closed cracks [18].…”

“…The second case deals with the scattering of a longitudinal wave resulting from the interaction between two incident shear waves and a closed crack. This last example corresponds to an application of the non-collinear mixing method [15,16,17,18].…”

Green-function Method for Nonlinear Interactions of Elastic Waves

“…Numerical methods such as finite element [1], [2] and finite difference time domain [3] are used to model nonlinear wave interactions in 2D and 3D configurations. These well known methods become inefficient at higher frequencies (MHz range and above) due to the requirement of 20 or more points per wavelength in the meshing grid.…”