Evaluation of Equivalent Stiffness Models for Estimating Modal...

Recent efforts to develop and evaluate equivalent stiffness models for estimation of modal frequencies of composite grid structures are summarized. The motivation for this work is that, instead of having to generate complicated 3-D finite element models of grid structures, a simple equivalent stiffness model (ESM) or finite element plate model having equivalent stiffnesses, can be developed for the prediction of the modal frequencies easily and economically. "Exact" finite element models of both orthogrid and isogrid structures have been developed to calculate the modal frequencies and corresponding mode shape for three different boundary conditions: free-free, cantilever and simply supported. Authors: MD. Shahidul Islam, Ronald F. Gibson, Wayne State University, Detroit, MI.