Numerical equilibrium analysis of a stack of steel post pallets
Józef Pelc
Abstract
A method for analyzing the equilibrium of a stack of loaded post pallets is presented. The finite element method was used to investigate the behavior of the bottom pallet in the stack during the addition of successive pallets. The stack was regarded as a self-stable multi-storey structure without bracings which is subjected to the weight of loaded pallets, horizontal forces resulting from sway and bow imperfections, and the impact of a forklift truck. The definite quadratic form of the tangent stiffness matrix after every increment in load was determined by nonlinear analysis to indicate the loss of post stability. An analysis of the stacking process of the evaluated pallets did not reveal a buckling trend in the posts of the bottommost pallet and demonstrated that the loss of equilibrium can lead to the collapse of the entire stack when a critical number of pallets is reached.
Keywords:
pallet, stack, equilibrium, stability, imperfection, warehouseReferences
BERNUZZI C., GOBETTI A., GABBIANELLI G., SIMONCELLI M. 2015a. Unbraced pallet rack design in accordance with European practice. Part 1: Selection of the method of analysis. Thin Walled Structures 86: 185–207.
BERNUZZI C., GOBETTI A., GABBIANELLI G., SIMONCELLI M. 2015b. Unbraced pallet rack design in accordance with European practice. Part 2: Essential verification checks. Thin Walled Structures 86: 208–29.
EN 1993-1-1:2005. Eurocode 3: Design of steel structures – Part 1.1: General rules and rules for buildings.
PELC J. 2017. Stability safety assessment for a stack of loaded steel post pallets. BiTP 47(3): 14–26, doi: 10.12845/bitp.47.3.2017.1.
PN-M-78205:1988. Steel pallets. Requirements and tests [Palety ładunkowe metalowe. Wspólne wymagania i badania].
PN-M-78207:1981. Post pallets. Basic parameters [Palety ładunkowe słupkowe metalowe. Parametry podstawowe].
SHAH S.N.R., SULONG R.N.H., JUMAAT M.Z., SHARIATI M. 2016. State-of-the-art review on the design and performance of steel pallet rack connections. Engineering Failure Analysis 66: 240–258.
TILBURGS CEES J. 2001. Racks for correctly used forklift trucks. Part 1 [Regały dla poprawnie użytkowanych wózków (Cz. 1)]. Logistyka 1: 33-40.
WOLNY S., ŁADECKI B., MATACHOWSKI F. 2014. Designing folding wall box pallets. Mechanics and Control 33: 37-41.
WOOD, R. 1992. Geometrically nonlinear finite element analysis. In E. Hinton (Ed.), NAFEMS Introduction to Nonlinear finite element analysis (pp. 90-94). Bell and Bain Ltd, Glasgow.
