Material Parameter Identification Of Orthotropic Composite Structure By The Finite Element Method

The composite material is a kind of advanced material widely used in every field of the society nowadays. Therefore, calibrating the material parameter of composite materials accurately is the foundation of design and evaluation of engineering structure.Substantial research on parameter identification of composite materials is discerned both at home and abroad at present. Directed towards the existing problems of measuring method at present, this thesis has put forward a kind of material parameter identification method of orthotropic composite structure that integrates finite element methods and optimization techniques.Based on the finite element method, an inverse method is developed to identify the material parameters of orthotropic composite structure. The inverse problem is formulated as the problem of minimizing the objective function defined as a square sum of differences between the measured and calculated data on displacements. Levevberg-Marquardt method, in which sensitivity analysis is based on the differentiation of the discretized algebraic finite element matrix equations, is used to solve the minimization problem.The method that this thesis put forward has fully utilized modeling commonability of finite element method, opens up a new way for the material parameter identification of orthotropic composite structure. Numerical example shows that the proposed method for parameter identification is effective.