Reanalysis of Large Finite Element Models with Structural Nonlinearities

摘要

Structural modification methods are widely used for design optimization purposes, especially for systems having large number of degrees of freedoms. By the use of these methods, modifications can be adapted to the system by avoiding reevaluation of dynamic characteristics of the modified system. In this paper, a method is proposed for the reanalysis of large finite element models having structural nonlinearities in order to reflect design variations. The finite element model (FEM) of the structure is divided into two parts representing the modified and unmodified sections. The modified part characterizes the sections where design variations are executed. Harmonic balance method (HBM) with modal superposition approach is used to convert the resulting nonlinear differential equations of motion into nonlinear algebraic equations. The modal information used in the nonlinear analysis is obtained from a new structural modification method with additional degrees of freedom details of which are given in another paper. Since the proposed method uses a model superposition approach, it can be applied to systems having large number of nonlinear elements. The proposed method is demonstrated on an example cantilever beam with nonlinear elements attached and the effect of design variations on the nonlinear response of the system is studied.