Effect Of Slenderness Ratio On Nonlinear-Static/Cyclic Behavior Characteristics Of Shear Panels

Thin-walled structures are widely used in different engineering applications. Bridge and building plate girders, box columns and girders, frame bracing systems, liquid and gas containment structures, shelters, offshore structures, ship structures, slabs, hot-rolled W-shape steel profiles, steel plate shear wall systems and many other naval and aeronautical structures are examples of engineering elements that according to their applications use plate of various thicknesses. The knowledge of the actual behavior of plates in such structures can be, of course, helpful in understanding the overall behavior of the structures. In general, plates in thin-walled structures may be under various types of loading, such as shear loading. Material yielding and geometrical buckling of plates are two independent phenomena which may well interact with each other in shear panels. Depending on the material properties, slenderness and aspect ratios, and boundary conditions of perfectly flat plates, yielding may occur before, after or at the same time as buckling. Buckling in slender plates is a local and sudden phenomenon followed by large out-of-plane displacements and loss of stiffness. Slender plates are capable of carrying considerable post-buckling additional loads due to stresses in the inclined tension fields. On the other hand, a plate with low slenderness ratio yields before buckles and thus, no post-buckling capacity is expected. In between, in plates with moderate slenderness ratios, material yielding and geometrical nonlinearity happen almost at the same time. In the present paper, the behavior characteristics of shear panels with simple or clamed boundary conditions and three different materials (carbon steel, stainless steel and aluminum) are studied for various plate slenderness ratios, using finite element method. Results of nonlinear static analyses of different shear panels show that slender plates, depending on the slenderness ratio, carry a relatively small shear load in the elastic stage until the occurrence of shear buckling, but their additional capacity in the post-buckling stage prior to yielding are significantly large. They reach their ultimate shear capacity slightly after yielding. That is, their post-yield capacity is not significant. Note that the ultimate shear strength of slender plates is considerably lower than their nominal shear yield strength. In plates with intermediate slenderness ratios, material yielding and buckling occur concurrently. They carry a relatively large shear load in the elastic stage before yielding/buckling. They have also some post-buckling/post-yield reserves before failure. The ultimate shear strength of moderate plates is somewhat lower than their nominal shear yield strength. In stocky plates, yielding precedes buckling. The shear capacity in the elastic stage before yielding is thus significant. The plates have some post-yield capacity and the ultimate load is coincident with the occurrence of plastic buckling (if happens). The ultimate shear strength of stocky plates is almost equal to their nominal shear yield strength. Moreover, results of quasi-static cyclic analyses of different shear panels show that the energy absorption capability, as expected, is very sensitive to the slenderness ratio of panels and with the decrease of the slenderness ratio (increase of thickness), the absorbed energy by the panels is substantially increased. For a specific slenderness ratio, steel shear panels exhibit higher energy absorption than panels with aluminum materials (although aluminum material has higher yield strength than that of carbon steel and stainless steel materials, here). This, of course, highlights the important role of the modulus of elasticity in the energy dissipation capability of shear panels. However, the material yield strength and panel boundary conditions do not seem to have important role in the amount of energy dissipated by the panels, compared to the material modulus of elasticity.