Identification of Nonlinear Materials by Finite Element Methods.

摘要

A method is developed to identify nonlinear material behavior. Discussed are the types of functionals that characterize various classes of nonlinear thermomechanical materials,the types of experiments needed to generate data capable of identifying nonlinear material constitutive functionals,and the inverse boundary value problem that models the identification problem. A new technique of material parameterization that uses finite elements defined over the multi-dimensional domain of the material operator is found to give very useful results. The identification problem is expressed as a system of nonlinear algebraic equations that couples the set of experimentally observed measurements and the discretized boundary value problem. A computer program is developed for the special case of isotropic,incompressible elastic materials. A wide range of numerical examples is studied to determine the accuracy and stability of this material identification algorithm. (Author)