Experimental investigation and numerical simulation of pallet-rack stub columns under compression load

North American standard requires physical tests to determine the capacity of a pallet-rack stub column. While predicting the column capacity and stiffness, finite element method based numerical simulation may not be considered reliable due to the existence of Initial Geometrical Imperfection (IGI). In this study, an expanded Ramberg-Osgood model is proposed to describe the stress-strain behavior of steel sheet material that exhibits a discontinuous yielding (i.e. relatively long yield plateau). The model was successfully employed in the simulations of the pallet-rack stub column. In order to reduce the prediction error caused by the IGI, an improved numerical simulation strategy was proposed. The strategy was validated by experimental tests, and it was compared with two classical strategies in terms of their prediction accuracy for the column's compression capacity and stiffness. Nonlinear analyses were performed by using a finite element analysis software, ANSYS, and the results show that the improved strategy is more unbiased and accurate.