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This work deals with the coupling of the Finite Element Method (FEM) and the Boundary Element Method (BEM) to model interacting saturated porous and sealed elastic media. In this coupled analysis, the porodynamic subdomains of the model are discretised by the FEM, and the elastodynamic interacting subdomains are discretised by the BEM. Nonlinearities may be considered within the FEM subdomains. An iterative coupling approach is adopted, which leads to an efficient and easy to implement formulation, enabling the FEM and BEM modules to be handled separately. The iterative coupling methodology allows nonlinear analyses to be carried out quite directly, considering a single iterative loop for all iterative computations. It also permits independent discretisations to be straightforwardly applied for each subdomain of the model, taking into account simple interpolation/extrapolation procedures on common interfaces. Optimal relaxation parameters are considered to speed up the convergence of the iterative coupling analysis. At the end of the manuscript, numerical examples are presented, illustrating the performance of the proposed formulation. [ABSTRACT FROM AUTHOR]

This paper discusses the coupling of finite element (FE) and boundary element (BE) methods for the solution of transient dynamic soil–structure interaction problems in the time domain. As both the FE and the BE method impose different requirements on the time step for reasons of stability and accuracy, iterative coupling schemes are applied since they allow for a different time discretization in both subdomains. Apart from a direct coupling approach, various sequential and parallel iterative coupling strategies are investigated, imposing either Neumann or Dirichlet boundary conditions on the FE and BE subdomains. The use of interface relaxation accelerates convergence, where Aitken׳s Δ 2 - method provides an optimal relaxation parameter for all iterative strategies considered. It is demonstrated that the boundary conditions applied to each subdomain strongly affect the efficiency of these algorithms; the application of Neumann boundary conditions on the stiffest subdomain results in the fastest convergence. The iterative coupling strategy is useful in the case where different time steps are used in both subdomains, though a direct coupling can also be used. The iterative coupling strategy is finally applied to the computation of ground vibrations from impact pile driving. [ABSTRACT FROM AUTHOR]