Analytical/experimental behavior of anisotropic rectangular panels under linearly varying combined loads

An analytical solution has been obtained for the buckling of anisotropic re ctangular panels subjected to several combinations of uniform shear and lin early varying biaxial in-plane loads, The principle of stationary value of the total potential energy was used for determining the buckling load of sy mmetric laminates through the solution of an eigenvalue problem; clamped an d simply supported boundary conditions along edges mere introduced into the analysis. The analytical results are in good agreement with the results co ncerning isotropic plates and the few results on infinitely long anisotropi c plates, The buckling load of panels under linearly varying biaxial in-pla ne loads is largely influenced by the transverse compression load and by th e boundary conditions along the four edges. Because no experimental results were found in the open literature, several tests were carried out on a gra phite-epoxy rectangular panel to verify buckling behavior under various loa ding conditions, 1) uniaxial compression, 2) biaxial compression, and 3) bi axial compression with uniform load in the longitudinal direction, and thre e transverse load conditions, 1) trapezoidal, 2) triangular, and 3) in-plan e bending. The maximum transverse load was of the same value as the longitu dinal compression load; the panel was clamped along the four edges. A numer ical analysis was also carried out by using the MSC/NASTRAN/PATRAN finite e lement code. The analytical, numerical, and experimental results show extre mely good correlation.