Dynamic Response of Flat Integrally Stiffened Graphite/Epoxy Panels Under Combined Acoustic and Shear Loads Available to Purchase

This project involved an experimental investigation into the effect of a high random acoustic loading, in combination with a static shear load near initial buckling, on the dynamic response of integrally stiffened graphite/epoxy panels. The program covered the design, fabrication, finite-element analysis, and testing of a J-stiffened monolithic panel and a J-stiffened minisandwich panel. The minisandwich panel had a syntactic core containing glass micro-balloons. The panels were designed to an initial shear buckling load of 17.51 kN/m (100 lb/in.). The predicted initial shear buckling load was, generally, in good agreement with the measured load. The damping, in all of the modes, increased significantly on approaching buckling. The root-mean-square strain, at the critical panel location, increased by as much as 30% in the vicinity of panel buckling, in spite of the increase in the damping.