NORMAL-MODE THEORY AS A TOOL IN FINITE-ELEMENT SUBSTRUCTURING

Two methods of substructuring finite element models are examined. Each method uses normal mode theory as the basis for selecting the appropr iate modes for the substructure and the properties of the modes. One o f the substructuring procedures uses component mode synthesis to attac h the substructure to the residual structure, while the other method u ses direct connection. The resulting combined models are evalated for shock input using NASTRAN, and the results are compared to the analysi s of the original model in each case.