Buckling analysis of transversely stiffened isotropic and orthotropic rectangular thin plates under shear loads by using ansys finite element program

In this study by using the ANSYS finite element program, eigenvalue bucklinganalyses of simply supported and transversely stiffened isotropic andorthotropic thin rectangular plates under shear loads were performed. 255buckling analyses based on 69 unstiffened / stiffened plate geometries wereconducted to reach the critical buckling loads and stresses of plates. Twodifferent simply supported boundary conditions were used and uniformlydistributed shear loads were applied along the transverse edges of the plates.Plate analyses were carried out with two different material groups; isotropic(mild steel) and orthotropic (Boron-Aluminium metal matrix composite).Isotropic and orthotropic plates were transversely stiffened with rectangularstiffeners with the same material usage. Consequently buckling stresses wereobtained and these results were compared with critical stresses of unstiffenedplates. Moreover, in the isotropic case, the effect of longitudinal stiffeners oncritical buckling stresses and the difference between transversely andlongitudinally stiffened plates were studied. Isotropic stiffeners were chosen asto be one-sided while orthotropic ones were double sided. In the modeling andanalysis stages in the ANSYS, the element type of mild steel plates and stiffenerswas chosen as Shell63 while the element type of Boron-Aluminium plates andstiffeners were chosen as Shell99. Consequently, the effect of different length-width ratios on (τcr.steel)stiffened / τcr.steel and EIs/aD ratios, the effect of height of thestiffeners on critical stress of plates and buckled mode shapes of plates arepresented as graphs, tables and figures respectively. In the unstiffenedorthotropic plates, 16 different fiber angle combinations were studied andrelated critical buckling stress variations were investigated and these resultswere shown as tables and graphs. Moreover, for critical buckling loads ofunstiffened orthotropic plates, ?LAMINA? Fortran program is used todetermine whether the failure occurs between the layers of composite plates ,according to Tsai-Hill failure criteria. Lastly, 5 different ?plate-stiffener fiberangle combinations? were tested for critical buckling in stiffened orthotropicplates.Science Code : 914.1.073Key Words : thin plates, orthotropic, stiffener, eigen value bucklinganalysis, shear loads, critical buckling stressPage Number : 199Advisers : Asst.Prof. Dr. Ezgi GÜNAY