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Kong Y.S.,National University of Malaysia | Kong Y.S.,APM Engineering and Research Sdn Bhd | Omar M.Z.,National University of Malaysia | Chua L.B.,APM Engineering and Research Sdn Bhd | Abdullah S.,National University of Malaysia
The Scientific World Journal | Year: 2013

This study describes the effects of bounce, brake, and roll behavior of a bus toward its leaf spring suspension systems. Parabolic leaf springs are designed based on vertical deflection and stress; however, loads are practically derived from various modes especially under harsh road drives or emergency braking. Parabolic leaf springs must sustain these loads without failing to ensure bus and passenger safety. In this study, the explicit nonlinear dynamic finite element (FE) method is implemented because of the complexity of experimental testing A series of load cases; namely, vertical push, wind-up, and suspension roll are introduced for the simulations. The vertical stiffness of the parabolic leaf springs is related to the vehicle load-carrying capability, whereas the wind-up stiffness is associated with vehicle braking. The roll stiffness of the parabolic leaf springs is correlated with the vehicle roll stability. To obtain a better bus performance, two new parabolic leaf spring designs are proposed and simulated. The stress level during the loadings is observed and compared with its design limit. Results indicate that the newly designed high vertical stiffness parabolic spring provides the bus a greater roll stability and a lower stress value compared with the original design. Bus safety and stability is promoted, as well as the load carrying capability. © 2013 Y. S. Kong et al. Source


Kong Y.S.,National University of Malaysia | Kong Y.S.,APM Engineering and Research Sdn Bhd | Omar M.Z.,National University of Malaysia | Chua L.B.,APM Engineering and Research Sdn Bhd | Abdullah S.,National University of Malaysia
Engineering Failure Analysis | Year: 2014

Parabolic leaf spring experiences repeated cyclic loading during operating condition. Fatigue life assessment of the parabolic leaf spring is a significant aspect during the component design stage. This paper serves to simulate the fatigue life of a parabolic leaf spring design under variable amplitude loading (VAL). VALs carry the road signal that provokes fatigue failure on leaf spring. In order to seek for comprehensive leaf spring fatigue assessment, VALs signal were gathered through measurements from various road conditions such as highway, curve mountain road and rough rural area road. Subsequently, fatigue life of particular leaf spring design was predicted using finite element (FE) stress-strain model together with VALs signal as load input. For more conservative way, Morrow and Smith Watson Topper (SWT) mean stress correction methods were also applied. The results indicate that fatigue life of leaf spring is lowest during rough road mission, followed by curve mountain road and smooth highway road respectively. Additional design modification to prolong the fatigue life of the parabolic leaf spring is compulsory. The road VALs has provided even more realistic fatigue life estimation of parabolic leaf spring design when compared to traditional controlled laboratory method. © 2014 Elsevier Ltd. Source


Nor M.A.M.,University Technology of MARA | Nor M.A.M.,APM Engineering and Research Sdn Bhd | Rashid H.,University Technology of MARA | Mahyuddin W.M.F.W.,APM Engineering and Research Sdn Bhd | And 3 more authors.
Procedia Engineering | Year: 2012

This paper aims to model, simulate and perform the stress analysis of an actual low loader structure consisting of I-beams design application of 35 tonne trailer designed in-house by Sumai Engineering Sdn. Bhd, (SESB). The material of structure is Low Alloy Steel A 710 C (Class 3) with 552 MPa of yield strength and 620 MPa of tensile strength. The scope of this study concern on structural design of the I-beams for info and data gathering, which will be used for further design improvement. Finite element modeling (FEM), simulations and analysis are performed using a modeling software i.e. CATIA V5R18.Firstly, a 3-D model of low loader based on design from SESB is created by using CATIA. Stress and displacement contour are later constructed and the maximum deflection and stress are determined by performing stress analysis. Computed results are then compared to analytical calculation, where it is found that the location of maximum deflection agrees well with theoretical approximation but varies on the magnitude aspect. Safety factor for the low loader structure has also been calculated. In the end, the current study is important for further improvement of the current low loader chassis design. © 2012 The Authors. Source


Kong Y.S.,National University of Malaysia | Kong Y.S.,APM Engineering and Research Sdn Bhd | Omar M.Z.,National University of Malaysia | Chua L.B.,APM Engineering and Research Sdn Bhd | Abdullah S.,National University of Malaysia
Advances in Mechanical Engineering | Year: 2014

The ride dynamic characteristics of an urban bus were investigated through simulations with suspension component characteristics and were validated through field measurements. It was performed on highway road at a constant forward speed. A random vibration bus model with two parallel tracks of terrain profile was synthesized with superposition between the left and right sides as well as time delay between front and rear. The bus frequency response model was introduced with embedded modal extraction data to enhance computation efficiency. The simulation results of the bus model were derived in terms of acceleration PSD and frequency-weighted root mean square acceleration along the vertical axes at three locations, namely, driver side, middle, and rear passenger side, to obtain the overall bus ride performance. Another two sets of new leaf spring design were proposed as suspension parameter analysis. The simulation approach provides reasonably good results in evaluating passenger perception on ride and shows that the proposed new spring design can significantly improve the ride quality of the driver and passengers. © 2014 Y. S. Kong et al. Source

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