##
**Finite element methods for a composite model in elastodynamics.**
*(English)*
Zbl 0684.73034

The propagation of elastic waves through an isotropic composite system consisting of an elastic solid with an embedded porous medium saturated by a compressible viscous fluid is studied. Boit’s low frequency dynamic equations are chosen to describe the propagation of waves within the porous medium while standard elastic wave equation is used for the rest of the medium. The weak form of the problem is described and the existence and uniqueness of the solutions are established. The continuous-time and discrete-time Galerkin procedures are defined and the corresponding error analyses are performed. The displacement vector components for the solid part of the medium are approximated by standard finite element subspaces, whereas the mixed finite element subspaces are employed to approximate the vector displacements for the porous medium. Certain smoothness assumptions for the solution of different problems are made to derive the convergence of optimal order for the methods.

Reviewer: V.K.Arya

### MSC:

74S05 | Finite element methods applied to problems in solid mechanics |

65C20 | Probabilistic models, generic numerical methods in probability and statistics |

74J10 | Bulk waves in solid mechanics |

65N30 | Finite element, Rayleigh-Ritz and Galerkin methods for boundary value problems involving PDEs |

86-08 | Computational methods for problems pertaining to geophysics |

76S05 | Flows in porous media; filtration; seepage |

35B65 | Smoothness and regularity of solutions to PDEs |

74S30 | Other numerical methods in solid mechanics (MSC2010) |

74G30 | Uniqueness of solutions of equilibrium problems in solid mechanics |

74H25 | Uniqueness of solutions of dynamical problems in solid mechanics |

74L10 | Soil and rock mechanics |