INVERSE PARAMETER ESTIMATION OF FLUID-SATURATED POROUS MEDIA BY SIMULATED ANNEALING ALGORITHMS

The simulated annealing algorithm is used to determine material parameters of fluid-saturated porous media from surface dynamic response data. Based on fitting of calculated results with experimental data, the inverse parameter estimation problem is transformed into an optimization problem. The complex motion equations and the nonlinear relations between dynamic response and material parameters result in a nonlinear and multimode objective function. The conventional gradient-orient optimal methods not only need complex sensitivity analysis of parameters to determine the search direction, but also fail usually to find the global extremum due to the pitfall of local extremum. In order to overcome the shortcoming, the simulated annealing algorithm is used. Numerical results indicate that the simulated annealing algorithm is robust for the inverse estimation problem of material parameters.