ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

5aPAa4. An efficient solution method for solving poroelasticity dynamic problems using the finite-element method.

Raymond Panneton

Noureddine Atalla

GAUS, Mech. Eng., Univ. of Sherbrooke, PQ J1K 2R1, Canada

Recently, a three-dimensional (3-D) finite-element formulation for the dynamic behavior of poroelastic materials was developed [Panneton et al., J. Acoust. Soc. Am. 96, 3339(A) (1994)]. The fluid and solid macroscopic displacements were used as the fundamental variables. The formulation was based on an analogy with 3-D elastic solid elements. However, six degrees-of-freedom (dof) per node were necessary. For large-scale finite-element models and multifrequency analyses, the use of 6 dof per node has proven to be time- and memory-consuming. Indeed, the complex dissipation mechanisms and frequency-dependent poroelastic coefficients prevent the use of efficient classical solution methods, such as mode superposition method. To alleviate the problem, an efficient solution method is presented. This method is based on assumptions about the poroelastic stress-strain relations and their frequency dependence. A parametric study on the dynamic behavior of poroelastic materials will be presented to back up the used assumptions. Finally, results will be shown to prove that the proposed method leads to substantial gain in computer time without loss of accuracy.