Applied Mechanics and Materials Vol. 165

Abstract: This paper presents the development of the UKM Perodua Eco-Challenge vehicle, CARevo in terms of aesthetic design, novel fabrication of car body and superior chassis design. The objective of the competition was to develop a fuel efficient car which was competent to travel the longest distance using 0.5 liter of RON95 fuel with some rules and regulation verified by the Perodua to be followed. The UKM CARevo was powered by a 660cc fuel injection engine with manual 5-speed transmission with the total of 3450 mm, 1500 mm and 1106 mm for its length, wide and height. Several design such as space frame chassis design, composite bodywork result from fiberglass with resin, aerodynamic design of car body and are the key features that is discussed in this paper.

Abstract: The leg injury criteria subjected to frontal impact is presented and discussed. The aim is to analyze the effect of steel material of bumper shell on pedestrian leg injury criteria of front bumper system. The front bumper beam is made of mild steel and characterized by impact modeling using LS-DYNA V971, according to United States New Car Assessment Program (US-NCAP) frontal impact velocity and based on European Enhanced Vehicle-safety Committee. The most important variable of this structure are mass, material, internal energy, and Leg Injury Criterion (LIC). In order to evaluate the protective performance of the baseline hood, the Finite Element Models (FEM) of legform of an adult pedestrian is used. The result shows that the acceleration of 91.5 g, shear displacement of 4.2 mm and bending angle of 12.0˚ graphs are performing below the danger limit. The reason found to be there were no contact between the front bumper beam and the legform, so that the injury is less. This is shows that the clearance between the bumper shell and front bumper beam are sufficient.

Abstract: The aim of this study is to analyze the effect of steel and composite material on pedestrian head injury criteria of hood system. The hood is made of mild steel and aluminum, e-glass/epoxy composite and carbon epoxy composite are studied and characterized by impact modeling using LS-DYNA V971 in accordance with United States New Car Assessment Program (US-NCAP) frontal impact velocity and based on European Enhanced Vehicle-safety Committee. The most important variable of this structure are mass, material, internal energy, and Head Injury Criterion (HIC). The results are compared with hood made of mild steel. Three types of materials are used which consists of mild steel as reference materials, Aluminum AA5182, E-glass/epoxy composite and carbon fiber/epoxy composite with four different fiber configurations. The in-plane failure behaviors of the composites were evaluated by using Tsai Wu failure criterion. The results for the composite materials are compared to that of steel to find the best material with lowest HIC values. In order to evaluate the protective performance of the baseline hood, the Finite Element models of 50th percentile an adult pedestrian dummy is used in parallel to impact the hood. It was found that aluminum AA5182 hood can reduce the Head Injury Criterion (HIC) by comparing with the baseline hood. For pedestrian crash, it is observed that Aluminum AA5182 hood gave the lowest HIC value with 549.70 for HIC15 and 883.00 for HIC36 followed by steel hood with 657.40 for HIC15 and 980.90 for HIC36, e-glass/epoxy composite hood with 639.60 for HIC15 and 921.70 for HIC36 and carbon/epoxy composite hood with 1197.00 for HIC15 and 1424.00 for HIC36.

Abstract: In this study, a computer program for calculating fatigue life of component is developed and introduced in LS-PrePost software. The program is written in Fortran programming language and the fatigue life equations used is taken from well-published literature. The materials covered are steel and aluminum. The developed program is able to read stress, strain and element values from d3plot and the keyword file. Having extracted the output from d3plot and keyword file, the fatigue life is then calculated and presented into a separate file called FATIGUE. The integration of output from FATIGUE will is displayed in LS-PrePost. Finally, the results of fatigue life contour are successfully displayed through LS-PrePost.

Abstract: This paper presents the performance of Aluminium Alloy side door subjected to side pole impact test. Aluminium Alloy is used in order to reduce the overall car weight. Therefore further improvements of the Aluminium Alloy side door system were carried out to obtain similar crash performance with the conventional steel side door system. The main crash performance properties are the internal energy, bending displacement, and mass. These properties were used to simulate the pole impact test using LS-DYNA Finite Element software. The improvements techniques used involved parameters such as thickness variation of the parts, ribs addition, beam shape variations, and combination of the factors. From the tests, three designs which include combination of parameters have met the target requirements. Thus, the use of Aluminium Alloy in side door system is acceptable provided there are improvements regarding the crash performance.

Abstract: A finite element (FE) model incorporating a progressive material damage with Rice-Tracey damage initiation criterion is developed in this study. The relationship between local ductility reduction and stress triaxiality was established experimentally. The FE model was validated by comparisons of load-displacement response of the spot welded lap joint specimen at displacement rate of 5 mm/min and the observed ductile failure mechanism. Results show that Rice-Tracey damage initiation criterion used is sufficient to reproduce the observed ductile failure response of the specimen. Failure of the spot welded lap joint is initiated at the HAZ/fusion zone interface with localized necking.

Abstract: This paper intends to present the application of FMEA method on Three-Way Catalytic Converter (TWC) system. Catalytic converter of auto-exhaust emission is one of the most successful applications of heterogeneous catalysis, both in commercial and environmental point of view. FMEA method will be applied to this system to quantitatively determine and evaluate its risk factors. This method is being employed effectively for identifying and addressing what potentially could go wrong with a product or process. It is expected to enhance the lifetime of the TWC by improving its resistance to deactivation. It is widely accepted that FMEA is one of the best quality improvement tool. For the last several decades, FMEA has been widely used in industry especially in automotive sectors. This research will cover mostly on the system and design of the TWC itself as the most important part for controlling the exhaust emission from automobiles. By improving its resistance to deactivation will contribute to longer lifetime of automotive catalytic converter.

Abstract: Vibration causes many problems in human health, comfort and performance. While walking with a backpack, movement of the backpack relative to the body causes a vibration which behaves like a spring that moves up and down following the motion of the body. In order to analyse the backpacks response to trunk motion, a backpack vibration system has been developed in this study. A model of a backpack-human trunk system, which is represented by a mass-spring system with a damper, and a Fourier series as an external force, is used to describe the motion of the vibration system. The vibration system was analysed using constant values of damping and spring stiffness (c =1 and k = 5) but with different values of the mass of the backpack. Increasing the mass of the backpack from 10% of body weight to 15 and 20% of body weight increased the amplitude of both the displacement and velocity of the backpack vibration system. However, the frequencies of the vibration system decreased as the mass of the backpack increased.

Abstract: This paper presents a study on root stresses of thin-rimmed helical gears with web arrangement of various rim and web thickness. Thin-rimmed helical gears used in this study were meshed with solid helical gear. Root stresses were measured from the beginning of engagement to the end of engagement by using the strain gauge method. The changes of root stresses from the beginning of engagement to the end of engagement were examined and the meshing position where the maximum root stress occurred (worst loading position) was determined. Effects of rim and web thickness on the root stress, the maximum root stress and the position of maximum root stress were clarified.

Abstract: This paper presents work conducted at the Universiti Kebangsaan Malaysia to support the HCCI Engine Program. The objective of this paper is to develop an engine that employs Homogeneous Charge Compression Ignition (HCCI) combustion and features using Palm Oil Methyl ester as fuel. A Novel of palm oil product usage for HCCI engine fuel was investigated. Different percentage of blend of Palm Oil Methyl Ester and RON 97 was tested using Digital Boom Calorimeter. An experiment based on 0%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% and 100% percentage blending between Palm Oil Methyl Ester and RON 97 produced results with an average of 39 MJ/g. Result shows that a high percentage blending of methyl ester with Ron 97 will increase the calorific value of fuel and this result also shows that a low pressure needed to ignite combustion in combustion chamber because of the high calorific value.