Applied Mechanics and Materials Vol. 315

Abstract: The paper presents the numerical studies of two different tubes under axial impact loading structures. The cylindrical tubes filled with closed-cell polymeric foam. The deformation and failure mechanism of this new structure were observed and analyzed numerically using the finite element method. It is revealed that the stress distribution and fracture of the foam-filled tube structure are different from those of foam-filled tube. In comparison with double cell foam-filled tubes, the load-carrying capacity of this new structure is much steadier, the collapse behavior resistance is enhanced, and the weight efficiency of energy absorption is higher. Parameters affecting the performance of the foam-filled tube structures are also studied. Comparison were carried out with load versus displacement curve and also dynamic mean load as well as dynamic absorbed energy versus deformation of tubular collapse modeling failure mode using finite element analysis.

Abstract: Generating new variants for design elements of products, structuring them into a complete configuration and evaluating the alternate configurations are essential for product design. Evaluating the likely product configurations in terms of sustainability aspects continues to become a useful aspect of interest to product designers. This paper proposes a new approach for applying the Product Sustainability Index (ProdSI) in selecting the best possible configurations for product design. In this paper, the recently developed ProdSI methodology is used to evaluate sustainability performance of a product. The approach is useful for product designers to generate numerous likely product design configurations and subsequently select the most sustainable product design configuration. An example of an armed-chair is used to illustrate the proposed new approach.

Abstract: This study is an approach to investigate the environmental impact of screw manufacturing and to choose suitable material for selected screw-making processes for the best performance with minimum environmental impact. The parameters involved were types of material and screw-making process using the environmental data available in Asia region. The two different manufacturing approaches being evaluated were machining and forging. The types of material considered were low carbon steel, stainless steel, titanium alloy and aluminium alloy. As for machining process, the materials being considered in screw manufacturing were low carbon steel, stainless steel, titanium alloy, aluminium alloy, magnesium alloy and cast iron. The information of environmental impact are generated by SolidWorks. Sustainability tool was used in the formation of pair-wise comparison matrices for Analytic Hierarchy Process (AHP). Then, the ranking of global priorities had enabled the determination of appropriate material to be used for those selected screw manufacturing process. As a result, aluminium alloy was found to give minimum environmental impact for forging process whereas cast iron was found to excel in machining process. At the same time, titanium alloy was not suggested to be used in either process.

Abstract: Rapid prototyping refers to building three dimensional parts in a tool-less, layer by layer manner using the CAD geometry of the part. Additive Manufacturing (AM) is the name given to the application of rapid prototyping technologies to produce functional, end use items. Since AM is relatively new area of manufacturing processes, various processes are being developed and analyzed for their performance (mainly speed and accuracy). This paper deals with the design of a new benchmark part to analyze the flatness of parts produced on High Speed Sintering (HSS) which is a novel Additive Manufacturing process and is currently being developed at Loughborough University. The designed benchmark part comprised of various features such as cubes, holes, cylinders, spheres and cones on a flat base and the build material used for these parts was nylon 12 powder. Flatness and curvature of the base of these parts were measured using a coordinate measuring machine (CMM) and the results are discussed in relation to the operating parameters of the process.The result show changes in the flatness of part with the depth of part in the bed which is attributed to the thermal gradient within the build envelope during build.

Abstract: After the oil crisis in 1973, renewable sources of energy are gianing more interest due to multiplicity feedstocks and lower pollution compared with fossil fuels. Wide agricultural lands through the world are not fully benefited. Therefore, farming should include the production of non-food products which are suitable to weather conditions of these lands. This leads to the production of biodiesels as renewable fuel for the domestic energy market, to reduce the dependence on fossil fuels. Biodiesel have gained a large interest of researches during the last few decades, the major reason to find an alternative fuel, is the increasing worry about the greenhouse gas effects and environmental regulations. Blended palm biodiesel with ordinary diesel fuel have been approved as a fuel for compression ignition engines without any modification. Palm biodiesel application is relatively limited to its poor cold flow properties characteristics. Many experimental studies are conducted to evaluate the influence of using different additives with Palm Oil Methyl Ester (POME) biodiesel/diesel blends on fuel properties (viscosity, cold properties, anticorrosiveness, cetane number, heat content, volatility) and engine performance. This article provides a literature survey on the effect of different additives to improve the fuel properties of palm biodiesel and engine performance. The review shows that the additive usage in palm biodiesel is accompanying for improving the cold flow properties and better engine performance as well emission regulation.

Abstract: Diamond coating on tungsten carbide (WC-Co) cutting tools with cobalt binder experiences delaminating failure due to the deleterious effect of cobalt. One of the methods used to reduce this effect is by coating an interlayer onto the substrate surface prior to diamond deposition. Different materials have been used as an interlayer which is normally deposited to the substrate surface using CVD and PVD techniques. Among different materials used as interlayer on WC-Co, nickel is considered as an attractive candidate due its good chemical and physical properties. In this study the potential of the electroplating technique for deposition of nickel interlayer on WC-Co will be investigated. Nickel deposition on WC-6%Co substrate was carried out by electroplating in a standard watts solution at constant plating parameters (Current: 0.1 Amp, electric potential: 1.0 V and pH: 3.5). The gap between anode and cathode was varied (5mm, 10mm and 15mm). The nickel coating formed on the hard metal surface was characterized in terms of the coating thickness, layer uniformity and coating hardness by using SEM and the micro hardness tester. Based on the results, desirable nickel coating properties were obtained when the separation distance between anode and cathode was 15mm.

Abstract: Cellular manufacturing system facilitates lean manufacturing in terms of production flexibility and control simplification. The paper presents a case study on a newly constructed cellular manufacturing system adopted by an electronic assembly factory as the back end process. The original rabbit chase is infeasible in this case because products handled are multi-types and multi-paths. Further, the cycle times are largely imbalance. The application of two proposed rabbit chase models was investigated through computer simulations enhanced with ANOVA and surface response methodology. The allocation of operators and the impact of changing lot size to the performances of the cell are investigated. For the findings, there are clear indications of the effects of the number of operators and the lot size for the performances of the system, regardless which rabbit chase model used.

Abstract: This paper presents a new drive control system for electric car with GPS system to measure the speed of the car-body. This drive control system uses a non-linear controller designed by following the Lyapunov stability theorem. The controller is designed in order to control the wheel slip when the car starts to accelerate on the slippery road condition. The effectiveness of this control system is verified by experiments.

Abstract: Assembly sequence planning (ASP) plays an important role in the production planning and should be optimized to minimize production time and cost when large numbers of parts and sub-assemblies are involved in the assembly process. Although the ASP problem has been tackled via a variety of optimization techniques, these techniques are often inefficient when applied to larger-scale problems. In this study, an approach using particle swarm optimization (PSO) is proposed to tackle one of the ASP problems which are optimizing the assembly sequence time. PSO uses a number of agents (particles) that constitute a swarm moving around in the search space looking for the best solution. Each bird, called particle, learns from its own best position and the globally best position. Experimental results show that PSO algorithm can produce good results in optimizing the assembly time, has a powerful global searching ability and fast rate of convergence.

Abstract: Fractal flow conditioner is a flow conditioner with a fractal pattern and used to eliminate turbulence originating from pipe fittings in experimental fluid flow applications. In this paper, steady state, incompressible, swirling turbulent flow through circle grid space filling fractal plate (Fractal flow conditioner) has been studied. The solution and the analysis were carried out using finite volume CFD solver FLUENT 6.2. The turbulence model used in this investigation is the standard k-ε model and the results were compared with the pressure drop correlation of BS EN ISO 5167-2:2003. The results showed that the standard k-ε model gave a good agreement with the ISO pressure drop correlation. Therefore, the model was used further to predict the effects of circle grids space filling plate thickness on the flow characteristics.