DOF Reduction Strategy for Large Order Finite Element Models

Abstract

State-of-the-art technologies in computation and software have led to ever increasing size of finite element models, simply because this is possible. While it is arguable that “degree-of-freedom” proliferation is unnecessary, there are some potential benefits to be realized, namely (1) commonality of stress and dynamic models and (2) employment of finite element models in the mid- and high-frequency ranges (normally the domain of statistical energy analysis). The conventional approach to Test Analysis Model (TAM) definition for modal testing is based on Guyan Reduction. The strategy encounters severe difficulties (due to Boussinesq type singularities) when shell and 3-D elasticity elements are used to build a finite element model (FEM). This paper describes a “load-patch” variation of Guyan Reduction that alleviates 3-D problematic singularities. Two illustrative examples are used to demonstrate advantages and benefits of the new TAM definition procedure.