Applied Mechanics and Materials Vol. 315

Abstract: Foam-filled enclosures are very common in structural crashworthiness to increase energy absorption. However, very less research has been targeted on potential use of natural/recycled material reinforced foam-filled tubes. Therefore, an experimental investigation was performed to quantify energy absorption capacity of polyurethane (PU) composite foam-filled circular steel tubes under quasi-static axial loading. The thickness of the tubes was varied from 1.9, 2.9 and 3.6 mm. The tubes were filled with PU composite foam. The PU composite foam was processed with addition of kenaf plant fiber and recycled rubber particles that were refined at 80 mesh particulates into PU system. The density of PU resin was varied from 100, 200 and 300 kgm^-3. The PU composite foam-filled tubes were crushed axially at constant speed in a universal testing machine and their energy absorption was characterized from the resulting load-deflection data. Results indicate that PU composite foam-filled tubes exhibited better energy absorption capacity than those PU foam-filled tubes and its respective empty tubes. Interaction effect between the tube and the foam and incorporation of filler into PU system led to an increase in mean crushing load compared to that of the unfilled PU foam or tube itself. Relatively, progressively collapse modes were observed for all tested tubes. Findings suggested that composite foam-filled tubes could be used as crashworthy member.

Abstract: This article deals with a way of interpretation the results of numerical simulations solved for the mechanism of lifting platform. Subject of analysis is the atypical design solution of lifting mechanism with one degree of freedom, which members are connected by revolute joints and linear sliding guidance. The mechanism movement is provided by linear hydromotors. Computational simulations are carried out by FEM, where linear coupling equations are used for modeling of revolute joints and linear sliding guidance is modeled by structural contact of rail and slider. The way of modeling and parameters setting of structural contact significantly affects the stability of numerical solutions and the obtained results. The authors assume that the interpretation of the observed behavior and results of the numerical simulations allow to deduce the mechanism operability and gives a clue for setting the gap of real bounds.

Abstract: The numerical analysis of large mechanical systems brings specific problems. As an example the contact of two surfaces can serve. The contact situation occurs when two surfaces touch each other. The pressure forces can be then transferred whilst the tension forces can not. The solution of mentioned large systems by FEM leads usually to the large number of degrees of freedom (DOF). Even the nowadays used HW equipment makes possible solving the large scale systems, in certain cases (especially when the number of DOFs exceeds approximately 1e7) it is convenient to use an alternative approach leading to shorter solution times and HW demands. One of these approaches is the substructure technique. The paper deals with the description of this technique used for the contact problem arising in the body of roller bearing.

Abstract: The ability of bearing liner to maintain the fluid film lubrication is crucial to its performance. This study is to investigate the pressure distribution for full film lubrication of wavy bearing liner. The results were compared to that from smooth bearing liner. These bearings were used with the palm oil based lubricant. CFD analysis was developed to determine the numerical data. A 60 mm bearing with ratio 0.5 of its diameter to length is simulated. This bearing has 250 µm in clearance and 200 µm in amplitude with semi rectangular circumferential surface waviness liner in shape. Pressure distribution of the bearing was influenced by the increment of the eccentricity ratio and the speed of shaft. The surface waviness liner bearing produces higher in pressure by comparing it with the smooth bearing. The maximum pressure was noted in the vicinity of minimum fluid film thickness where it was distributed at the area around the peak of wave.

Abstract: This paper discusses the strategies for integrating Quality, Environmental, Safety and Health Management Systems based on survey and case studies results. Questionnaires were distributed to 87 companies that certified with both ISO9001 and ISO14001. Meanwhile, three case studies were conducted at the manufacturing companies that have integrated several management systems. There are two ways of integrating the management systems which are: (1) consecutive implementation of management systems followed by integration or (2) integrate the management systems simultaneously from the beginning. Based on survey and case studies, it was found that many organisations started with implementing individual management system first, and then followed by integrating the management systems. Almost all the survey respondents agreed that the sequence should start with establishing Quality Management System first, and then integrate with Environmental Management System and followed by Occupational Health and Safety Management System.

Abstract: Enterprise Resource Planning (ERP) system is integrated software that linked the functional areas in the organization by using and sharing the database in one platform. The implementation of ERP system in most of the manufacturing plants help in simplifying the production and scheduling system and smoothing the process flow which will lead the organisation towards lean manufacturing environment. Most of the manufacturers do not analyse and review on the effectiveness and implications of the ERP system at the post implementation stage. This study was established to address the impacts of the ERP system in leveraging the lean practices at the shop floor and the recommendations for the continuous improvement initiatives. Data for analysis has been retrieved from in house ERP system and from manual record system of a company that already implemented ERP system. Questionnaires have been distributed to ERP users within Malaysia and Singapore to gain insight the related issue of using ERP system in their company. The study provides evidence on the effectiveness and positive impacts of the ERP system to support manufacturing industries to become more lean and agile. ERP system also effectively to response to the customer requirement and added the value along the supply chain.

Abstract: Polypropylene (PP) composites have better material properties such as good strength, better stiffness, improve of ductility; good stability and thermal expansion; and low cost of production. Nevertheless, these properties depend on the matrix phase, the phase dispersion of fillers and strengthening mechanism, shapes and arrangements of filler particles and the bonding interface between filler and matrix [1]. Plaster of paris (POP) has been chosen as filler in this composite system because it is used in many ceramic manufacturing and construction sectors which produce lots of POP wastes. It becomes one of the environmental issues due to the amount of used POP that has been disposed without recycling. Therefore, it is crucial to develop new composite material which consists of recycled POP as filler in order to assist the government in addressing the environmental issue.

Abstract: The fretting wear of coated SCMV (high-strength alloy steel) substrate with interlayer is studied with the focus on stresses associated with the coating failure under gross sliding condition. The analysis is simulated using finite element based method for a given number of cycles of worn half cylinder-on-flat geometry. The effect of interlayer stiffness on the stress distributions in the coating is studied. The maximum tensile stress at the trailing edge and the maximum compressive stress at the leading edge are reducing with increasing interlayer stiffness. The maximum shear stress at the coating-interlayer interface is predicted to have negligible effect with the change of interlayer stiffness. All the stresses are generally predicted to reduce with cycle. In general, stiffer interlayer will reduce the risk of coating failure.

Abstract: This paper presents corrosion behaviour of welded low carbon steel at different welding parameters. Welding process was conducted using metal inert gas (MIG) technique at welding voltage range of 19 to 22 V with 1 V interval, and wire feed rate range of 90 to 120 inch per minute (ipm) with 10 ipm interval. Filler material used was ER 70S-6 with 1.2 mm diameter. Corrosion behaviour of welded carbon steel was tested using synthetic seawater environment with 3.5 wt% NaCl. Microstructure changes and penetration level of weldments were observed using scanning electron microscope (SEM). Results showed that, corrosion rate decreased when the welding voltage and wire feed rate increased with full penetration level of weldment attainment. The lowest corrosion rate occurred at the highest welding voltage and wire feed rate when full penetration of weldment occurred. From metallographic study, iron oxides and pitting was found on the surface of the exposed area after the corrosion test.

Abstract: This research is conducted in order to determine the best composition of alumina-cullet ceramic with the addition of mica powder. The alumina-cullet-mica composites (ACMCs) were produced by using powder compaction method. All raw materials used such as alumina, cullet and mica for fabricating the samples were first mixed, compacted and finally the samples have to undergo the sintering process. It is observed from the physical, mechanical and morphological analyses that the properties of ACMCs are highly dependable on the mica content.