In the supply chain there are three components: transportation method, the pallet, and the packaging. Traditionally, there has been a poor understanding of the way that pallet design can impact the supply chain. There are historical studies that illustrate the importance of investigating how box stacking pattern, unit load type, unit load size, and containment can impact the pallet's performance. However, there have been no studies that have investigated the impact of drums and plastic pails on pallet performance. The goal of the current research study was to investigate how plastic pails and drums affect pallet bending and the distribution of the pressure on the top surface of the pallet. The investigation was conducted using four different support conditions commonly found in warehouses: racking across the width and length, single stacking, and double stacking. The results of the investigation indicated that for most support conditions, loading the pallet with plastic pails or drums results in a significant reduction in deflection when compared to a uniformly distributed load. The maximum observed reduction in pallet deflection was 85% when testing with drums in the double stack condition and 89% when testing with plastic pails in the single stack condition. The large reductions in deflection could indicate that the pallets were over-designed for the unit load that they were supporting. Pressure mat distribution images collected during the experiment display a load bridging effect where the stress of the drums and pails are redistributed to the supported sides of the pallet. The data also show that drums made of different materials distribute the pressure onto the pallet in a significantly different manner. / Master of Science / Wood pallets are crucial to the supply chain that delivers the goods and objects that sustain our economy. Every product order or product that is seen in stores was sent through the supply chain. The supply chain is made up of three major interacting components, the material handling system, the packaging, and the pallet. By further understanding the interaction between these components, pallet and packaging designers can better utilize materials and maximize the efficiency of the supply chain. There is a need to understand how different types of packages interact with the pallet to effectively design pallets and to potentially reduce costs and material usage. Historical studies focused on investigating how corrugated boxes affect pallet performance. They mainly focused on the effect of corrugated box size, flute type, stretch wrapping and containment, and the influences that pallet design have on pallet performance. Past studies identified that packages on the top of the pallet could create a bridging between the packages that can reduce the stresses on the pallet and consequently increase its load capacity. By using this load bridging effect for their advantage, pallet designers can design pallets that are safer, cheaper, and be more environmentally friendly since current wood pallets are designed under the assumption of a uniformly distributed, rather than bridged, load. The goal of the current study was to investigate how the load bridging effect created by pails and drum affects the deflection of the pallet in the floor stacked loading condition. The investigation was conducted using four different support conditions commonly found in warehouses such as racking across the length, racking across the width, single stacking, and double stacking. The results of the investigation indicated that for most investigated support conditions, the interaction between pails and drums causes an increase in load bridging which significantly reduces the bending of the pallet. The reductions reached a maximum of 85% when testing with drums in the double stack condition and 89% when testing with plastic pails in the single stack condition. The large reductions in deflection could indicate that the pallets were over-designed for the unit load that they were supporting.

Thesis (MEng)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: The main goal of the thesis is to validate the ability of discrete element methods (DEM) to predict forced granular flow. Granular flow occurs in a broad spectrum of industrial applications. The thesis focuses on earthmoving processes typical of the mining and agricultural industries. Existing soil mechanics soil-tool models are also investigated and general flow behaviour in and around blades and buckets are established. Soil mechanics theories are used to predict the draft forces on a flat blade moving through granular material. Com and wheat grains are used as material. The rupture (slip) lines in front of the blade are predicted by soil mechanics and compared to experimental results. A two-dimensional test bench is used to visualise the flow of the granular material. Forces and moments that act on the tools are measured. DEM can be used to model industrial granular flow with large displacements. Two types of earthmoving equipment are simulated. The first is a flat blade and the second is a bucket. The forces on these tools are determined using DEM and compared to experimental results. The ability of DEM to predict material compressibility, the flow of material in and around the tools, the rupture lines and the bucket fill rate are investigated. A particle relative displacement method is used to determine the rupture lines. / AFRIKAANSE OPSOMMING: Die hoofdoel van die tesis is om die vermoë van diskrete-element-metodes (DEM) om geforseerde partikelvloei te voorspel, te ondersoek. Partikelvloei word aangetref in 'n breë spektrum van industriële toepassings. Die tesis fokus op grondverskuiwing soos aangetref in myn- en landbouprosesse. Bestaande grondmeganika-modelle word ook ondersoek, asook die algemene gedrag van partikelvloei in en rondom lemme en bakke. Die grondmeganika-modelle word hoofsaaklik gebruik om die kragte op lemme te voorspel. Glip (skuif)-vlakke word ondersoek en vergelyk met eksperimentele resultate. 'n Twee-dimensionele toetsbank word gebruik om die vloei waar te neem. Die kragte en momente op die toerusting word ook gemeet. Mielie- en koringpitte word as materiaal gebruik. DEM kan gebruik word om industriële partikelvloei met groot verplasings te modelleer. Twee tipes toerusting word gesimuleer. Die eerste is 'n plat lem en die tweede 'n bak. Die kragte en momente op dié toerusting word bepaal m.b.V. DEM en dan vergelyk met die eksperimentele resultate. Die vermoë van DEM om materiaalsamedrukking, vloeipatrone, glipvlakke en bakvul-tempo's te voorspel word ondersoek. 'n Partikelrelatiewe- verplasings-metode word gebruik om die glipvlakke te voorspel.