|Auteur(s):||S. Catheline, J.L. Gennisson, X. Jacob, M. Tanter, C. Barrière, D. Royer et M. Fink.
|Titre:||“Elastic nonlinearity of soft solids with transient elastography.”
|Référence:||Proc. 7ème Congrès Français d'Acoustique, CFA, France, Strasbourg vol. No. , pp -, Mars 2004
|Type de publication:||Communications à des conférences avec actes
If nonlinearity has long been studied in metals, crystals or rocks, almost no experimental works is found in the literature concerning soft tissues. Thanks to the ultrafast scanner, we present in this paper an overview of three transient elastography experiments that quantify the nonlinear behavior of a soft tissue phantom. In the first one, a static stress is applied on a phantom. The change on the shear wave speed characterizes the nonlinear elastic Landau moduli. The surprising difference found between these constants are thought to be closely related to the huge difference between the linear Lamé coefficients (λ >> µ). It is the acoustoelasticity experiment. In the second one, we present the first experimental observation of a shock shear wave. The very weak Young’s modulus of the tissue phantom allows one to generate plane shear wave with a Mach number as high as unity. In this extreme configuration, the agreement with the theoretical prediction of the modified Burgers equation is remarkable. It is the finite-amplitude shear wave experiment. At last, the interaction between two plane transverse waves with frequencies ω1 and ω2 is carefully studied. Harmonics are created during the propagation at the frequencies (3ω1, 3ω2, ω1+2ω2, ω1-2ω2, ω2+2ω1, ω2-2ω1). It is the parametric interaction experiment. This set of three experiments involves plane transverse waves. The feasibility of measuring the nonlinear elastic coefficient with non plane shear wave is discussed in the last section.
Document associé [182556 octets]: Proc_Elasto1D&2D_Nonlinéaire_CFA_2004.pdf