BUCKLING AND FAILURE CHARACTERISTICS OF COMPRESSION-LOADED STIFFENED COMPOSITE PANELS WITH A HOLE

An experimental and analytical study was carried out to investigate th e buckling and failure characteristics of stiffened compression-loaded panels with holes, and to assess the validity of analytical models us ed for the design of such panels. Graphite-epoxy panels with four equa lly spaced blade stiffeners were fabricated with a laminate stacking s equence optimally designed for stiffened panels without holes. Panels with different hole sizes and panels without holes were tested. Failur e of all panels initiated at or near the stiffeners, in regions with s evere local bending gradients. Finite element analysis using a quarter -panel model with boundary conditions to simulate the experiment was u sed to predict the prebuckling and buckling behavior. Analytical resul ts correlate well with experimental results.