Mohd Afendi Rojan
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Preferred name
Mohd Afendi Rojan
Official Name
Mohd Afendi , Rojan
Alternative Name
Afendi, Mohd
Rojan, M. Afendi
Afendi Rojan, M.
Afendy, M.
Rojan, M. A.
Mohd Afendi, R.
Afendi, M.
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Scopus Author ID
57188766103
Researcher ID
GQR-0248-2022

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  • Publication
    Effect of FSW parameters on temperature profile and grain size of AA6061-T6 and S275JR mild steel FSW joint
    ( 2021-05-03)
    Wan Mohd Syafiq Wan Sulong
    ;
    Mohd Afendi Rojan
    ;
    Mazlee Mohd Noor
    Friction stir welding (FSW) is a solid-state welding technique used to join materials such as aluminum alloy, magnesium alloy, steel and titanium. The process involves relatively low process temperatures compared to other conventional welding techniques. Welded material undergoes severe plastic deformation driven by the rotating FSW tool, which causes dynamic recrystallization of grains. In this study, the temperature during the welding of AA6061-T6 aluminum alloy and S275JR mild steel was recorded using K-type thermocouple. Grains in the stir zone (SZ) of joints were observed in order to measure the grain size. Samples were etched with Keller's reagent to reveal its microstructure. It was seen that the highest temperature was recorded when welding with a high tool plunge depth. Decreasing tool travel speed was seen to increase temperature readings. The lowest temperature was recorded when using a high tool tilt angle due to a reduced contact area between tool shoulder and weld piece. Largest observed grain size was measured in the SZ of the joint welded with a high tool plunge depth, due to the high process temperature experienced by the joint during welding.
  • Publication
    Effective elastic constants of corrugated core sandwich plate microstructure considering imperfection in adhesive bonding
    ( 2017-10-29)
    Hazman M.
    ;
    Khairul Salleh Basaruddin
    ;
    Nur Saifullah Kamarrudin
    ;
    Mohd Shukry Abdul Majid
    ;
    Mohd Afendi Rojan
    Imperfection of adhesive bonding in the corrugated core sandwich plate microstructure is commonly occured due to inaccuracies in fabrication process or environmental effect. Considering the geometrical changed due to the adhesive imperfection, it could influence the mechanical properties of sandwich plate structure. Hence, this paper was caried out to predict the effective elastic constants of corrugated core sandwich plate microstructure by considering the effect of adhesive imperfecction. Unit cell of corrugated core microstructure with variation of adhesive imperfection was developed using multiscale finite element software named Voxelcon. Homogenization method was integrated with probability function to predict the effective elastic constants of corrugated core sandwich plate structure. The proposed method could potentially be extended to other types of periodic microstrostructure in predicting the reliable homogenized properties of heterogeneous materials.
  • Publication
    Study of eddy current density distribution in a contactless breast cancer detection mechanism using magnetic induction spectroscopy
    ( 2017-01-01)
    Gowry Balasena
    ;
    Shahriman Abu Bakar
    ;
    Zulkarnay Zakaria
    ;
    Ryojun Ikeura
    ;
    Zuradzman Mohamad Razlan
    ;
    Hazry Desa
    ;
    Wan Khairunizam Wan Ahmad
    ;
    Cheng Ee Meng
    ;
    Mohd Afendi Rojan
    Breast cancer is a throbbing disease that no longer needs an introduction. This is especially true among women due to their unique breast structure that naturally has more breast tissues compared to that of man’s. It is been forecasted that in 2015, a minimum of 60290 new cases of breast cancer will be reported. The goal of this study is to analytically evaluate the changes in the induced Eddy current densities as a function of di-electrical properties of the breast tissue with respect to tumor positioning as well as its size. This is achieved by running numerical simulations on the proposed mechanism of magnetic induction to detect tumors among healthy breast tissue via a 2D breast model configuration. The analytical results presented in this article, proved that the multi frequency magnetic induction principle is viable in detecting the breast lesions as small as 0.2 cm non-invasively through the distributions of the induced Eddy current density. While important pattern of the induced current were reflected when the tumors are located at the far ends of the breast diameter. The minimum results computational time with the proposed system is 10 s.
  • Publication
    Fatigue life investigation of UIC 54 rail profile for high speed rail
    ( 2017-10-29)
    Gurubaran Panerselvan
    ;
    Mohd Afendi Rojan
    ;
    Nur Fareisha M. A.
    ;
    Mohd Shukry Abdul Majid
    ;
    Haftirman I.
    ;
    Md. Tasyrif bin Abdul Rahman
    This study is to investigate the fatigue life of high speed rail in Malaysia. This paper describes about the experimental and simulation analysis investigation on fatigue life of rail profile UIC 54 using bulk specimen according to ASTM E 466-15 standard. The Fatigue life testing was performed in the fatigue testing machine (Instron 8800) 100 kN. Meanwhile, the fatigue life analysis was performed in ANSYS Workbench 14.5. Furthermore, the stress levels for experimental testing were applied as 16.7%, 25%, 35%, 50%, 58.3%, 66.77% and 75% with machine frequency of 20 Hz. Apart from that, the total fatigue life cycles for rail profile UIC 54 were acquired from both experimental and simulation. The fatigue life S-N curves were plotted and validated with the results of the simulation analysis with experimental results.
  • Publication
    Approach to enhance the heat transfer of valve seats through thermal analysis
    ( 2022-02-05)
    Hassan M.A.S.M.
    ;
    Zuradzman Mohamad Razlan
    ;
    Shahriman Abu Bakar
    ;
    Mohd Afendi Rojan
    ;
    Wan Khairunizam Wan Ahmad
    ;
    Ibrahim Z.
    ;
    Ishak A.A.
    ;
    Rahman A.A.
    ;
    Mohd Ridzuan Mohd Jamir
    The valve seat insert is a component of the engine cylinder head, whose primary function is to seal the combustion chamber and absorb the valve's heat, releasing it to the engine cylinder head. The valves experience high temperatures owing to high thermal loading and low heat absorption in the valve seat, which can potentially damage the engine. Therefore, the thermal characteristics of the valve seat must be optimised to increase the heat transmission between the valve and its seat. Here, three copper alloy valve seats, brass, beryllium copper, and bronze copper, were tested against the existing sintered iron valve seat, and their temperature maps were determined using actual engine operation conditions. The instantaneous heat transfer coefficients of the valves, seats, and engine cylinder head during the four-stroke cycle were evaluated using a one-dimensional thermal simulation analysis. The values obtained were used to assess the finite-element model using a three-dimensional thermal simulation in the Ansys software. The results show that the brass, beryllium-, and bronze-copper valve seats increased the overall heat flux by 4.46%, 4.16%, and 2.06%, respectively, compared to those for sintered iron. Thus, the results are essential to improve the thermal characteristics of the copper alloy valve seat imposed on the cylinder head. For validation, an experimental engine thermal survey and uncertainty magnification factors were used to validate the model. The results indicate that the maximum difference between the simulation and experimental values is 8.42%. Therefore, this approach offers a direct and comprehensible application for evaluating the temperature distribution, heat gradient, and heat flux of the cylinder head of air-cooled spark-ignition moped motorcycle engines using copper alloy valve seat materials at intermediate engine speeds. Furthermore, this method is applicable as a platform for the automotive industry to improve the heat transfer of the structural parts of internal combustion engines.
  • Publication
    Finite element modelling of thin intermetallic compound layer fractures
    ( 2017)
    Ooi Eang Pang
    ;
    Ruslizam Daud
    ;
    Nasrul Amri Mohd Amin
    ;
    Mohd Afendi Rojan
    ;
    Mohd Shukry Abdul Majid
    A thin intermetallic compound (IMC) of solder ball joint induces strong stress concentration between the pad and solder where a crack propagated near the IMC layer. The fracture mechanism of the IMC layer is complex due to the effect of IMC thickness, crack length, solder thickness and Young’s Modulus. At present, there is still an undefined exact geometrical model correlation for numerical simulations of IMC layer fracture. Thus, this paper aims to determine the accuracy of IMC layer models subjected to crack-to-width length ratio (a/W) in correlation with the ASTM E399-83 Srawley compact specimen model using finite element (FE) analysis. Several FE models with different geometrical configurations have been proposed under 10 MPa tensile loading. In this study, the two dimensional linear elastic displacement extrapolation method (DEM) is formulated to calculate the stress intensity factor (SIF) at the crack tip. The study showed that with an error of 0.58% to 0.59%, a width of 2.1 mm and a height of 1.47 mm can be recommended as the best geometrical model for IMC layer fracture modelling which provides a wider range for a/W from 0.45 to 0.85 instead of from 0.45 to 0.55. This result is significant as it presents a method for determining fracture parameters at thin IMC layers with a combination of singular elements with meshes at different densities which is tailored to the Srawley model.
  • Publication
    Formation of polypropylene nanocomposite joint using silicon carbide nanowhiskers as novel susceptor for microwave welding
    ( 2023-05-01)
    Foong P.Y.
    ;
    Voon Chun Hong
    ;
    Lim B.Y.
    ;
    Teh P.L.
    ;
    Mohd Afendi Rojan
    ;
    Subash Chandra Bose Gopinath
    ;
    Mohd Khairuddin Md Arshad
    ;
    Nor Azizah Parmin
    ;
    Low F.W.
    ;
    Ruslinda A. Rahim
    ;
    Uda Hashim
    Up to present, no study has reported on the use of silicon carbide nanomaterials (SiCNMs) as susceptor for microwave welding of thermoplastics. Therefore, in this study, silicon carbide nanowhiskers (SiCNWs) was attempted as the microwave susceptor for the microwave welding of polypropylene (PP). It was observed that SiCNWs are capable of absorbing microwave and converting them into heat, leading to a sharp increase in temperature until it reaches the melting point of PP substrates. The microwave welded joint is formed after the molten PP at the interface between PP substrates is cooled under pressure. The effect of microwave heating duration and solid loading of SiCNWs suspension was studied and reported. The formation mechanism of SiCNWs reinforced PP welded joint was proposed in this study. With these remarkable advantages of microwave welding and enhanced mechanical properties of the welded joint, it is believed that this study can provide a new insight into welding of thermoplastic and material processing through short-term microwave heating.
  • Publication
    Finite element modelling of thin intermetallic compound layer fractures
    ( 2017)
    Ooi Eang Pang
    ;
    Ruslizam Daud
    ;
    Nasrul Amri Mohd Amin
    ;
    Mohd Afendi Rojan
    ;
    Mohd Shukry Abd Majid
    A thin intermetallic compound (IMC) of solder ball joint induces strong stress concentration between the pad and solder where a crack propagated near the IMC layer. The fracture mechanism of the IMC layer is complex due to the effect of IMC thickness, crack length, solder thickness and Young’s Modulus. At present, there is still an undefined exact geometrical model correlation for numerical simulations of IMC layer fracture. Thus, this paper aims to determine the accuracy of IMC layer models subjected to crack-to-width length ratio (a/W) in correlation with the ASTM E399-83 Srawley compact specimen model using finite element (FE) analysis. Several FE models with different geometrical configurations have been proposed under 10 MPa tensile loading. In this study, the two dimensional linear elastic displacement extrapolation method (DEM) is formulated to calculate the stress intensity factor (SIF) at the crack tip. The study showed that with an error of 0.58% to 0.59%, a width of 2.1 mm and a height of 1.47 mm can be recommended as the best geometrical model for IMC layer fracture modelling which provides a wider range for a/W from 0.45 to 0.85 instead of from 0.45 to 0.55. This result is significant as it presents a method for determining fracture parameters at thin IMC layers with a combination of singular elements with meshes at different densities which is tailored to the Srawley model.
  • Publication
    Effect of Microwave Power and Clamping Pressure on the Microwave Welding of Polypropylene Using Silicon Carbide Nanowhiskers as Microwave Susceptor
    ( 2022-01-01)
    Foong P.Y.
    ;
    Voon Chun Hong
    ;
    Lim B.Y.
    ;
    Teh P.L.
    ;
    Mohd Afendi Rojan
    ;
    Nor Azizah Parmin
    ;
    Subash Chandra Bose Gopinath
    ;
    Mohd Khairuddin Md Arshad
    ;
    Low F.W.
    ;
    Mahalingam S.
    ;
    Manap A.
    ;
    Ruslinda A. Rahim
    ;
    Uda Hashim
    Due to their excellent dielectric properties and the rapid response to microwave irradiation, silicon carbide nanowhiskers (SiCNWs) were employed as microwave susceptor in this study to absorb microwave and locally melt the surrounding polypropylene (PP) substrates for the joining of PP substrates. Complete welded joint is formed after the melted PP was cooled and resolidified. Other than microwave susceptor, SiCNWs also acted as the nanofillers in strengthening the welded joint through the formation of SiCNWs reinforced PP nanocomposite at the interface of PP substrates. Besides, the effect of microwave power on the microwave welding of PP substrates using SiCNWs as susceptor was studied and reported. It was found that the tensile strength and modulus of elasticity of the welded joint improved as microwave power increased. However, it deteriorates the flexibility of the welded joint as high stiffness SiCNWs were incorporated deeper into the PP matrix which restricted the PP chain mobility. Aside from microwave power, clamping pressure is also critical in determining the mechanical properties of a welded joint. When compared to unclamped welded joint, the tensile strength, modulus of elasticity and flexibility of welded joint subjected to clamping pressure improved drastically. Moreover, the tensile strength of welded joint increased when the clamping pressure was increased from P1 to P3, but decreased when the clamping pressure was further increased to P4 due to the occurrence of flashing at welded joint. The formation mechanism of SiCNWs reinforced PP welded joint was also proposed in this study. Compared to conventional welding, this welding process is easy, straightforward and is able to produce welded joint with outstanding mechanical properties via precise controlling of the processing parameters. Thus, microwave welding is thought to offer an option for the joining of thermoplastics and other applications.
  • Publication
    Influence of friction stir welding parameters on joint defects, temperature and hardness of AA6061-T6 and S27JR mild steel FSW joint
    ( 2021-10-25)
    Wan Mohd Syafiq Wan Sulong
    ;
    Mohd Afendi Rojan
    ;
    Mazlee Mohd Noor
    The influence of welding parameters such as tool plunge depth, tool travel speed and tool tilt angle on welding temperature during friction stir welding of AA6061-T6 and S275JR mild steel was the focus of this research. Thermocouple placed in the aluminum alloy plate prior to welding was used to measure the temperature during the welding of joints under different set of parameter values. Joint appearance as well as defects occurring on the surface or within the joint was observed. Microhardness profiles were also taken by measuring microhardness values across the cross section of joints. Excessive flash, tunnel defects and insufficient welding were the type of weld defects observed on different joints with different parameters. Defects were attributed to the varied parameter values affecting the heat generation as well as the flow of the plasticized material. Highest temperature was recorded by the joint fabricated using the largest tool plunge depth, owing to the increased downwards pressure. Microhardness profiles were seen to be similar for all the welded joints. A “plateau” of low microhardness value was observed for all joints associated with the thermomechanically affected zone (TMAZ) and heat affected zone (HAZ). A wider plateau was observed for joints welded with higher tool plunge depth due to higher temperature.