Applied Mechanics and Materials Vol. 315

Abstract: Supplier selection is one of the important processes in supply chain management. Regarding the emergence of sustainability issues in recent decades, companies have incorporated these issues in conventional supplier selection in order to meet governmental legislations and market demands. These issues have been noticed by various researchers. However, there are limited research activities which considered all aspects of sustainability for supplier selection problem as an integrated assessment. In this paper, an integrated approach of Fuzzy Analytical Hierarchy Process and fuzzy logic has been proposed in order to solve sustainable supplier selection problem. Fuzzy analytical hierarchy process has been used to calculate the weight of sustainable criteria and sub criteria. Then, fuzzy logic was utilized in order to assess the suppliers based on the weights acquired by Fuzzy analytical hierarchy process. Finally, a case study of petroleum industry has been carried out in order to show the validity of proposed approach.

Abstract: In this paper, the optimization of surface roughness, cutting force, feed force and tool life in a turning operation was investigated by using Taguchi method and fuzzy logic. The experiment were conducted under varying cutting speeds, feed rates, depths of cut and noses radius. An orthogonal array, the signal-to-noise (S/N) ratio, grey relational analysis, grey-fuzzy reasoning grade and analysis of variance were employed to the study the performance characteristics in the turning AISI D2. Experimental results have shown that machining performance characteristics in turning process can be improved effectively through the combination of Taguchi method and fuzzy logic.

Abstract: This paper studies the effect of mesh topologies such as hybrid and structured meshes on the evaluation of wall heat transfer coefficient (HTC) and pressure loss of a blade cooling passage. An experimental model is chosen; it has five-row of stream wise staggered elliptical pin-fin fitted inside a 10^o wedge-shape duct and one-row of fillet circular pin-fin in the exit region. Simulations consider two types; i.e. warm test with isothermal wall condition and cold test with adiabatic wall condition respectively, in order to evaluate flow and thermal characteristics such as HTC and pressure loss. Further simulations are carried out by varying Re number, wall surfaces roughness, inlet turbulence intensity and turbulence models. It was found that for unstructured or structured mesh with proper near wall and middle passage grid resolutions, CFD predicted HTC and pressure loss are in good agreement with available experimental data. The wall surface roughness is found to have significant impact on HTC, simulations produce results in better agreement with experimental measurements. Simulation results also confirm that inlet turbulence intensity and turbulence model have insignificant effect of predicting the pin-fin wall and end wall heat transfer coefficient.

Abstract: In this paper, a new Artificial Neural Network (ANN) model that relates human comfort and electrical power consumption of a building with temperature, illumination and carbon dioxide (CO₂) level inside the building is developed. The model has been developed using samples of simulated data representing the indoor environment variables. Results have shown that neural network with 14 hidden layer neurons produces outputs that is closest to the actual system outputs.

Abstract: In Polymer Electrolyte Membrane Fuel Cell (PEMFC), bipolar plate is considered one of the most important components. Bipolar plate has a multi-functional in the fuel cell stack. The materials used in producing bipolar plate are greatly affecting its final properties. Through this study, the properties of bipolar plate composite will be observed. The based composition of this composite is 80% for multi-filler material and 20% binder material. Polypropylene (PP) will be used as binder material and for filler materials, Graphite (Gr) is the main filler and for the second filler materials its will vary with the usage of Carbon Black (CB), Iron (Fe), and Aluminum (Al) powder. The formation of this composite is produced through compression molding. The effect of different filler material loading on the properties such as electrical conductivity, bulk density and shore hardness are observed. The result showed the increasing of electrical conductivity as the increased the CB and Fe loading. But for Al, the result showed the decreasing of electrical conductivity as the loading of Al has been increased. Meanwhile the usage of CB clearly shown an improvement in electrical conductivity and able to meet the DOE target properties for development of PEMFC bipolar plate.

Abstract: The paper presents an integrated steering system design for bus drivers drowsy driving behaviour change. Busses involved in accidents due to drowsy driving is increasing nowadays and those accidents involved a lot of people due to the number of passengers it carries. In order to decrease the rate of accidents for bus driver due to drowsy driving, an integrated steering system that can change their driving behaviour is developed. The developed integrated steering system is then being validated through surveys conducted on drivers with valid driving licence. The survey results have shown that the integrated steering system is a feasible system to the drivers.

Abstract: Current UTeMs fire fighting machine is developed to operate indoor only. It is not efficient when it is operating on rocky surfaces (outdoor) as it faces the problem of shock and vibration reduction. The track system of the machine cannot move smoothly because the rollers are fixed to the chassis. This paper describes the method of up-scaling and optimising the track system for the current fire fighting machine. The new track system concept is firstly developed by using Computer-Aided Design (CAD) and Computer Aided Engineering (CAE) software. Subsequently a prototype is built to validate the functionality of the new track system which is more efficient in absorbing the vibration and shock. Analysis and optimisation of the prototype is performed using CAD method with the CATIA V5 R16 software.

Abstract: Hard turning is a dominant machining operation performed on hardened materials using single-point cutting tools. In recent years, hard turning operation has become more and more capable with respect to various machinability criteria. This work deals with machinability of hardened DF-3 tool steel with 55 ±1 HRC hardness at various cutting conditions in terms of tool life, tool wear mechanism and surface roughness. Continuous dry turning tests were carried out using coated, mixed ceramic insert with honed edge geometry. Two different cutting speeds, 100 and 210 m/min, and feed rate values of 0.05, 0.125 and 0.2 mm/rev were used with a 0.2 mm constant depth of cut for all tests. Additionally scanning electron microscope (SEM) was employed to clarify the different types of wear. As far as tool life was concerned, best result was achieved at lowest cutting condition whereas surface roughness values decreased when operating at higher cutting speed and lower feed rate. Additionally maximum volume of material removed is obtained at low cutting speed and high feed rate. Dominant wear mechanism observed during the experiments were flank and crater wear which is mainly caused by abrasive action of the hard workpiece material with the ceramic cutting tools.

Abstract: Drawbead are often used to control the flow of material, stress and deep drawing force in the flange area. This paper discussed the drawbead (fully, not fully and without drawbead) that combined with variations in the blank holder force against restriction of material flow and drawbead restriction force of deep drawing with palm oil lubrication. In this paper, analytical and experiments are used to predict the drawbead restraining and deep drawing force. The tin steel sheet with a thickness of 0.2 mm is used as speciment. The results obtained, that the application fully drawbead be very effective in controlling the flow of materials in the flange, as compared to not fully and without drawbead. In the beginning of the process (punch stroke < 4 mm), the magnitude of restraining force and deep drawing force can be increased. And, the magnitude of Radial Stress increases, conversely the magnitude of tangential stress decreased. This can prevent the occurrence optimum blank holder force is recommended in range 4394-8788 N. Comparisons of results between the analysis and experiments show the phenomenon is similar.

Abstract: Catalytic steam gasification of Malaysia Waste Palm Tree Trunk Derived Bio-char was studied using alkali metal carbonate (K₂CO₃) supported perovskite oxide catalysts which showed a favor catalytic activity in the carbon combustion. The bio-char steam gasification reactions were carried out using a fixed reactor under a steam atmosphere with different catalysts, such as K₂CO₃/LaMn_0.8Cu_0.2O₃, K₂CO₃/Alumina, Nikel/LaMn_0.8Cu_0.2O₃, Nikel/Alumina, and Alumina, respectively. The effects of temperature, catalyst support and catalysts mixing ratio on the syngas compositions and carbon conversion were carefully investigated. The syngas compositions were analyzed by gas chromatography (GC). K₂CO₃/LaMn_0.8Cu_0.2O₃ catalyst showed better carbon conversion compared to the other catalysts, which indicated the Perovskite Oxide was more effective as a support for the gasification catalyst. The results showed that the better carbon conversion within short time removed nearly 100% of heavy and light tar.