Wave Propagation in Viscoelastic and Poroelastic Continua: A Boundary Element Approach

1. Introduction.- 2. Convolution quadrature method.- 2.1 Basic theory of the convolution quadrature method.- 2.2 Numerical tests.- 2.2.1 Series expansion of the test functions f1 and f2.- 2.2.2 Computing the integration weights ?n.- 2.2.3 Numerical convolution.- 3. Viscoelastically supported Euler-Bernoulli beam.- 3.1 Integral equation for a beam resting on viscoelastic foundation.- 3.1.1 Fundamental solutions.- 3.1.2 Integral equation.- 3.2 Numerical example.- 3.2.1 Fixed-simply supported beam.- 3.2.2 Fixed-free viscoelastic supported beam.- 4. Time domain boundary element formulation.- 4.1 Integral equation for elastodynamics.- 4.2 Boundary element formulation for elastodynamics.- 4.3 Validation of proposed method: Wave propagation in a rod.- 4.3.1 Influence of the spatial and time discretization.- 4.3.2 Comparison with the "classical" time domain BE formulation.- 5. Viscoelastodynamic boundary element formulation.- 5.1 Viscoelastic constitutive equation.- 5.2 Boundary integral equation.- 5.3 Boundary element formulation.- 5.4 Validation of the method and parameter study.- 5.4.1 Three-dimensional rod.- 5.4.2 Elastic foundation on viscoelastic half space.- 6. Poroelastodynamic boundary element formulation.- 6.1 Biot's theory of poroelasticity.- 6.1.1 Elastic skeleton.- 6.1.2 Viscoelastic skeleton.- 6.2 Fundamental solutions.- 6.3 Poroelastic Boundary Integral Formulation.- 6.3.1 Boundary integral equation.- 6.3.2 Boundary element formulation.- 6.4 Numerical studies.- 6.4.1 Influence of time step size and mesh size.- 6.4.2 Poroelastic half space.- 7. Wave propagation.- 7.1 Wave propagation in poroelastic one-dimensional column.- 7.1.1 Analytical solution.- 7.1.2 Poroelastic results.- 7.1.3 Poroviscoelastic results.- 7.2 Waves in half space.- 7.2.1 Rayleigh surface wave.- 7.2.2 Slow compressional wave in poroelastic half space.- 8. Conclusions - Applications.- 8.1 Summary.- 8.2 Outlook on further applications.- A. Mathematic preliminaries.- A.1 Distributions or generalized functions.- A.2 Convolution integrals.- A.3 Laplace transform.- A.4 Linear multistep method.- B. BEM details.- B.1 Fundamental solutions.- B.1.1 Visco- and elastodynamic fundamental solutions.- B.1.2 Poroelastodynamic fundamental solutions.- B.2 "Classical" time domain BE formulation.- Notation Index.- References.