MODAL TECHNIQUE FOR 3-DIMENSIONAL GLOBAL LOCAL STRESS-ANALYSIS OF PLAIN WEAVE COMPOSITES/

A global/local method based on modal analysis was developed which faci litates the three-dimensional stress analysis of plain weave composite structures. This requires minimal computational effort while retainin g reasonable accuracy. Homogenized material properties were used for t he global analysis. The global response of a region of interest was de composed into a few fundamental macroscopic modes which were either st rain modes or stress modes. The strain modes were calculated from the boundary displacements and the stress modes were calculated from the b oundary forces. To obtain the detailed local solution for the region o f interest, unit modal solutions were scaled by the modal magnitudes a nd then superposed. The unit modal solutions were calculated a priori using a refined local model. A short cantilevered plate subjected to e nd moment and transverse end load was analyzed to evaluate the perform ance of the proposed method. Failure initiation predicted by the propo sed method was found to match reasonably well with the conventional fi nite element prediction obtained using a detailed mesh for the entire plate. (C) 1997 Elsevier Science Ltd.