Comparison between linear and nonlinear buckling loads of FGM cylindrical panel with cutout

Abstract

This paper investigates the influences of effective parameters on the Difference between the Linear and Nonlinear Buckling Loads (DLNBL) of Functionally Graded Material (FGM) perforated cylindrical panel. In this regard, the panel was simulated using spline finite strip method. The linear and nonlinear buckling loads of the panel were obtained from linearized eigenvalue method and nonlinear geometric analysis. A comparison was made between the results obtained from the model developed in this study and those available in the literature to evaluate the validity of the results obtained from the model. Through a parametric study, the influences of different effective parameters such as cutout size, cutout shape, ratio of radius to thickness and power of FGM on the difference between the linear and nonlinear buckling loads of the panel were investigated. Although for the panels without cutout, the DLNBL was about 2 percent, it reached to 40 percent for the panels having cutout. As the cutout area increases or cutout shape changes from circle to long ellipse, the DLNBL increases significantly. Moreover, the DLNBLs obtained for shallow and FGM panels were lower than those for the deep and isotropic panels. The results obtained indicate that the buckling load obtained from linearized eigenvalue method is overestimated by about 40% for the FGM panel having long elliptical cutout. Finally, contour graphs were derived to determine the maximum difference between linear and nonlinear buckling loads of FGM panel based on the shape of cutout, size of cutout and ratio of radius to thickness of the panel. According to these graphs, the linearized eigenvalue method is not a proper method to obtain the buckling load of panels having long elliptical cutout and deep panels having medium elliptical cutout.