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Last update: T_KG (20.05.2002)
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Last update: T_KG (11.04.2008)
Students will be acquainted with the theory of elastic wave propagation in layered media and with various possibilities of matrix formulation of particular problems. |
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Last update: RNDr. Pavel Zakouřil, Ph.D. (05.08.2002)
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Last update: T_KG (11.04.2008)
Lecture |
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Last update: T_KG (19.01.2003)
Simple types of dispersion relations; expressions in terms of determinants; Knopoff's method. 2. Matrix method for Love waves Model of a layered medium. Expressions for the displacement and stress for plane shear waves. Matrix for one layer; matrix for a stack of layers. Dispersion relation for Love waves in a layered medium. Various modifications of the dispersion relation: Thomson-Haskell matrices, Knopoff's matrices. Some problems of programming: matrices with real elements, elimination of overflow. Various representations of the dispersion curves. Computation of eigenfunctions; accuracy of the results. 3. Application of matrix methods to other types of problems SH body waves in a layered medium: motion of the free surface due to the incidence of a plane wave from below; reflection and transmission at a transition zone. Temperature and electromagnetic waves in a layered medium. 4. Matrix method for Rayleigh waves Expression for the displacement and stress in terms of potentials. Matrices of the fourth order (4x4) for one layer and for a stack of layers. Dispersion relation for Rayleigh waves. Loss-of-precision problems in the methods of the Thomson-Haskell type, their causes. Matrix formulations eliminating the loss of precision: associated matrices 6x6 (delta-matrices, Thrower, Dunkin), reduced associated matrices 5x5 (Watson). Acquaintance with computer programs. 5. Computing the group velocity and some derivatives Computing the group velocity and the partial derivatives of the phase and group velocities with respect to the parameters of the medium: numerical differentiation, analytical computation using variational methods and the implicit-function method. |