Normal Mode Theory as a Tool in Finite Element Substructuring

Abstract

Two methods of substructuring finite element models are examined. Each method uses normal mode theory as the basis for selecting the appropriate modes for the substructure and the properties of the modes. One of the substructuring procedures uses component mode synthesis to attach the substructure to the residual structure, while the other method uses direct connection. The resulting combined models are evaluated for shock input using NASTRAN, and the results are compared to the analysis of the original model in each case.