ADJOINT NUMERICAL METHOD FOR THE IDENTIFICATION OF THE LAMÉ COEFFICIENTS IN LINEAR ELASTIC WAVE FIELD

Abstract

The purpose of this research is to propose a numerical method for the problem of the identification of the elastic coefficients in linear elastic wave field : Determine unknown Young’s modulus and Poisson’s ratio from the knowledge of the plural sets of simultaneous displacement and traction on the surface of an isotropic, linearly elastic bounded body. The elastic body is supposed to be a state of the plane strain. We assume that the density is known in the elastic body. In this research, the Lamé coefficients are identified instead of determining unknown Young’s modulus and Poisson’s ratio. To determine the unknown Lamé coefficients numerically, we adopt the adjoint numerical method. The minimizing problem with some constrains is introduced by using variational method. To find the minimum, a technique based on the projected gradient method is proposed. By numerical experiment, we discuss about the efficacy of our algorithm.