Abstract:

What is presented in this paper is a method of finite element model updating via design parameters using test modal data. Based on orthogonality relation ships, the method adjusts the design parameters instead of the elements of mass and stiffness matrices. The Taylor's series of the system matrices expanded with respect to design parameters is adopted. The conducted set of linear equations is solved by a singular value decomposition technique. Because of the linear relation of system matrices with the most design parameters, the method is suitable to the cases of the severe change of the parameters, and the parameters converge to the “true value” by only several iterations. The problems, such as the effect of errors on the test modal parameters, the expansion of the degree of freedoms of test mode shapes, etc, are handled. The weighted global fit procedure is used to pre-process the test mode shapes- to smooth the shapes and expand the degree of freedoms of the shapes simultaneously. The method can not be only applied to the finite element model updating, but also to the structural dynamics redesign. Numerical and practical examples show the efficiency and accuracy of the method.

Key words: structural model, finite element method, dynamic experiment