Now showing 1 - 10 of 44
  • Publication
    Finite element prediction on the chassis design of UniART4 racing car
    ( 2017-09-26)
    Zaman Z
    ;
    ; ;
    Md Taufiqur Rahman Sarkar
    ;
    This paper presents the analysis and evaluation of the chassis design for University Automotive Racing Team No. 4 (UniART4) car based on finite element analysis. The existing UniART4 car chassis was measured and modelled geometrically using Solidwork before analysed in FEA software (ANSYS). Four types of static structural analysis were used to predict the chassis design capability under four different loading conditions; vertical bending, lateral bending, lateral torsion and horizontal lozenging. The results showed the chassis subjected to the highest stress and strain under horizontal lozenging, whereas the minimum stress and strain response was obtained under lateral bending. The present analysis result could provide valuable information in predicting the sustainability of the current UniART car chassis design.
  • Publication
    Determination of effective elastic properties of metal matrix composites with damage particulates using homogenization method
    The present study aims to investigate the effect of micro-damage in particulates metal matrix composite on the elastic properties. The micro damage that perhaps could occurs during manufacturing process or due to environmental effects was modelled in three different types, namely shattered, debonded and breakage particulates with variation of volume fraction. The modelling and analysis were conducted based on homogenization theory by utilizing multiscale finite element software (Voxelxon). The results suggest that the elastic properties of metal matrix composite was sensitive to the geometrical defects of its particle.
  • Publication
    Correlation between postural stability and lower extremity joint reaction forces in young adults during incline and decline walking
    (MDPI, 2023)
    Noor Arifah Azwani Abdul Yamin
    ;
    ;
    Muhammad Farzik Ijaz
    ;
    Hiroshi Takemura
    ;
    ;
    Postural stability may be affected during slope walking, as there are different body kinetics and kinematic responses compared with level walking. Understanding body adaptations toward different inclinations is essential to prevent the risk of injury from falls or slips. This study was conducted to determine the correlations between stability parameters and loading response in terms of joint reaction force at the lower-extremity joints during inclined and declined walking. Twenty male subjects walked in the level, incline, and decline directions on a custom-built platform at three different slope angles (i.e., 5°, 7.5°, and 10°). To determine the ground reaction force (GRF), joint reaction force (JRF), center of pressure (COP), and center of mass (COM), a motion capture system was used to read the data of the ten reflective markers and transfer them to visual three-dimensional (3D) software. Pearson’s correlation test was performed with statistical significance set at p < 0.05 to evaluate the correlation of the required coefficient of friction (RCOF), postural stability index (PSI), and COP-COM distance with the JRF. This study has identified that the JRF changes in opposition to the changes in the RCOF during the initial strike during incline and decline walking, as JRF increases, the RCOF decreases with different strengths of correlation. There is also a strong positive correlation between the PSI and JRF in the proximal–distal direction, where the JRFs change in accordance with the change in the PSI, and the JRF increases with the increment of PSI. In addition, the JRF of the lower extremity also changed in a manner similar to the COP-COM distance in the medial–lateral direction. Overall, each stability parameter was correlated with the JRF of the lower-extremity joints in different directions and strengths. This study demonstrated that slope walking is particularly affected by surface inclination in terms of stability and loading. Therefore, this research can serve as a basis for future studies on slopes, as there is no specific basis for a maximum degree of inclination that is safe and suitable for all applications.
  • Publication
    Performance analysis of diabetic retinopathy detection using fuzzy entropy multi-level thresholding
    Diabetic Retinopathy (DR) is one of the major causes of blindness. Many DR detection systems were developed to segment and determine the type and number of lesions that appeared on retinal images and used to classify DR and its severity level. Even though several researchers have already proposed many automated diagnosis systems with different image segmentation algorithms, their accuracy and reliability are generally unexplored. The accuracy of an automated diagnosis system usually depends on the segmentation techniques. The accuracy of this system is heavily dependent upon the retinal and image parameters, which have intensity level difference between background (BG)-blood vessels (BV), BV-bright lesions, BV-dark lesions, and noise levels. In this work, the automated diagnosis system accuracy has been analysed to successfully detect DR and its severity levels. The focus is on fundus image modalities segmentation based on fuzzy entropy multi-level thresholding. The analysis aimed to develop conditions to guarantee accurate DR detection and its severity level. Firstly, a retinal image model was developed that represents the retina under the variation of all retinal and image parameters. Overall, 45,000 images were developed using the retinal model. Secondly, feasibility and consistency analysis were performed based on a specific design Monte Carlo statistical method to quantify the successful detection of DR and its severity levels. The conditions to guarantee accurate DR detections are: BG to BV > 30% and BV to the dark lesions (MAs) >15% for mild DR, BG to BV > 40% and BV to the dark lesions (MAs and HEM) > 20% for moderate DR, and BG to BV > 30% and BV to the dark lesions (MAs and HEM) > 15%, and BV to the bright lesions (EX) > 55% for severe DR. Finally, the validity of these conditions was verified by comparing their accuracy against real retinal images from publicly available datasets. The verification results demonstrated that the condition for the analysis could be used to predict the success of DR detection.
  • Publication
    Effect of sloped walking on ground and joint reaction forces
    (AIP publishing, 2023)
    Noor Arifah Azwani Abdul Yamin
    ;
    ;
    N. Z. A. C. Zahar
    ;
    ; ;
    Zahran Khudzari
    Sloped walking is commonly known to be benefited to health. However, the increase of GRF that contribute to increment to JRF during inclined walking compared to level-ground walking also has been a concern in preventing injury. Therefore, the aim of this study was to assess the effect of sloped walking in comparison with level-ground walking to GRF and JRF at hip, knee and ankle joints. Ten healthy male participants (age: 24 ± 1.2 years old with normal body mass index (BMI)) were asked to walk at preferred speed on customized ramp at the slopes of -5°, 0° and 5°. Kinematic data were captured with five-camera motion capture system (Qualysis Track Motion). Kinetic data were measured with two force plate (Bertex) which embedded into the ramp. A musculoskeletal model (Visual 3D C-motion) was used to assess joint reaction force (JRF) of lower limb. Result show that peak value of mean GRF as well as maximum JRF at all joints of lower limb were higher during sloped walking compared to level-ground walking. In addition, the maximum JRF at hip is the highest, followed by knee and ankle for all walking conditions. GRF had a significant influence to the JRF at lower limb during inclined and declined walking where sloped walking have a higher force at all joints of lower limb than level- ground walking. Therefore, a suitable walking strategy in adapting the forces demand is required in preventing any slope slippage and/or vertical body instability that might lead to musculoskeletal injury.
  • Publication
    Benchmarking artifact of selective laser sintering (SLS) components fabricated with flexible and rigid polymers
    This study aims to assess the performance of an Additive Manufacturing (AM) machine, specifically a Selective Laser Sintering (SLS) machine, through the design and evaluation of a benchmarking artifact. Drawing from insights gained in previous research, the artifact is meticulously crafted with two distinct materials to explore potential variations in geometric accuracy. The artifact comprises two types: one featuring straight geometries and another incorporating curved elements. The research methodology involves printing both artifact types at default machine settings, followed by precise measurements using a 3D scanner. The inclusion of straight and curved features facilitates a comprehensive examination of the machine’s ability to reproduce diverse geometries. The amalgamation of these features into a combined artifact provides a holistic assessment of the machine’s overall performance. To validate the benchmarking artifact, the final design is reproduced, and its output is compared not only with the original design but also with real-life parts. The results show that flexible polymers offer higher accuracy but lower resolution, while rigid polymers provide better resolution but with a greater number of defects. This comparative analysis serves to highlight the accuracy and reliability of the benchmarking artifact in reflecting the machine’s performance in practical scenarios. In conclusion, this study endeavours to advance the understanding of an SLS machine’s capabilities by leveraging a carefully designed benchmarking artifact.
  • Publication
    Performance analysis of diabetic retinopathy detection using fuzzy entropy multi-level thresholding
    ( 2023-07-01)
    Qaid M.S.A.
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    ;
    Yazid H.
    ;
    ; ;
    Ali Hassan M.K.
    Diabetic Retinopathy (DR) is one of the major causes of blindness. Many DR detection systems were developed to segment and determine the type and number of lesions that appeared on retinal images and used to classify DR and its severity level. Even though several researchers have already proposed many automated diagnosis systems with different image segmentation algorithms, their accuracy and reliability are generally unexplored. The accuracy of an automated diagnosis system usually depends on the segmentation techniques. The accuracy of this system is heavily dependent upon the retinal and image parameters, which have intensity level difference between background (BG)-blood vessels (BV), BV-bright lesions, BV-dark lesions, and noise levels. In this work, the automated diagnosis system accuracy has been analysed to successfully detect DR and its severity levels. The focus is on fundus image modalities segmentation based on fuzzy entropy multi-level thresholding. The analysis aimed to develop conditions to guarantee accurate DR detection and its severity level. Firstly, a retinal image model was developed that represents the retina under the variation of all retinal and image parameters. Overall, 45,000 images were developed using the retinal model. Secondly, feasibility and consistency analysis were performed based on a specific design Monte Carlo statistical method to quantify the successful detection of DR and its severity levels. The conditions to guarantee accurate DR detections are: BG to BV > 30% and BV to the dark lesions (MAs) >15% for mild DR, BG to BV > 40% and BV to the dark lesions (MAs and HEM) > 20% for moderate DR, and BG to BV > 30% and BV to the dark lesions (MAs and HEM) > 15%, and BV to the bright lesions (EX) > 55% for severe DR. Finally, the validity of these conditions was verified by comparing their accuracy against real retinal images from publicly available datasets. The verification results demonstrated that the condition for the analysis could be used to predict the success of DR detection.
      2  25
  • Publication
    Alternative assessment for enhancing complex problem-solving skills in mechanical system design course
    (Universiti Malaysia Perlis, 2024)
    Traditional assessment methods in engineering education, such as exam-based evaluations, often fail to adequately measure complex problem-solving skills and practical application of knowledge, necessitating the exploration of innovative assessment approaches. This paper introduces the Constructive-Teamwork-Experiential-Presentation (CTEP), an alternative assessment approach applied in the Mechanical System Design course (ENT348) for undergraduate mechanical engineering students. The CTEP model is tailored to enhance complex problem-solving (CPS) abilities and engage students in complex engineering activities (CEA). It aligns with the 2020 standards of the Engineering Accreditation Council (EAC) and the Malaysian Qualifications Framework (MQF) 2.0, specifically addressing Programme Outcomes (PO) 3 (Design) and PO10 (Communication). Over four academic terms, this model incorporated interactive design tasks, collaborative teamwork, simulation exercises, and student presentations. The findings indicate notable improvements in achieving PO3 and PO10, with average attainment rates rising to 80% and 78%, respectively. Beyond academic achievements, the model also supported the development of essential skills such as creativity, collaboration, and effective communication. Challenges related to time management and limited resources were mitigated through guided supervision and institutional backing. Future studies aim to evaluate the potential of extending the CTEP model to other engineering disciplines.
      2
  • Publication
    Effect of sloped walking on ground and joint reaction forces
    ( 2023-04-24)
    Noor Arifah Azwani Abdul Yamin
    ;
    ;
    Zahar N.Z.A.C.
    ;
    ;
    Salleh A.F.
    ;
    Khudzari A.Z.M.
    Sloped walking is commonly known to be benefited to health. However, the increase of GRF that contribute to increment to JRF during inclined walking compared to level-ground walking also has been a concern in preventing injury. Therefore, the aim of this study was to assess the effect of sloped walking in comparison with level-ground walking to GRF and JRF at hip, knee and ankle joints. Ten healthy male participants (age: 24 ± 1.2 years old with normal body mass index (BMI)) were asked to walk at preferred speed on customized ramp at the slopes of -5°, 0° and 5°. Kinematic data were captured with five-camera motion capture system (Qualysis Track Motion). Kinetic data were measured with two force plate (Bertex) which embedded into the ramp. A musculoskeletal model (Visual 3D C-motion) was used to assess joint reaction force (JRF) of lower limb. Result show that peak value of mean GRF as well as maximum JRF at all joints of lower limb were higher during sloped walking compared to level-ground walking. In addition, the maximum JRF at hip is the highest, followed by knee and ankle for all walking conditions. GRF had a significant influence to the JRF at lower limb during inclined and declined walking where sloped walking have a higher force at all joints of lower limb than level- ground walking. Therefore, a suitable walking strategy in adapting the forces demand is required in preventing any slope slippage and/or vertical body instability that might lead to musculoskeletal injury.
      1  18
  • Publication
    Lower extremity joint reaction forces and plantar fascia strain responses due to incline and decline walking
    ( 2021-01-01)
    Noor Arifah Azwani Abdul Yamin
    ;
    ; ;
    Ahmad Faizal Salleh
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    ;
    Purpose: The present study aims to investigate the effect of incline and decline walking on ground and joint reaction forces (JRF) of lower extremity and plantar fascia strain (PFS) under certain surface inclination angles. Methods: Twenty-three male subjects walked on a customized platform with four different surface inclinations (i.e., 0°, 5°,7.5° and 10°) with inclined and declined directions. The motion of the ten reflective markers was captured using Qualysis motion capture system (Qualysis, Gothenburg, Sweden) and exported to a visual three-dimensional (3D) software (C-motion, Germantown, USA) in order to analyze the GRF, JRF and PFS. Results: The results found that the peak vertical GRF is almost consistent for 0° and 5° inclination slope but started to decrease at 7.5° onwards during decline walking. The most affected JRF was found on knee at medial-lateral direction even as low as 5°, to 10° inclination for both walking conditions. Furthermore, the findings also show that the JRF of lower extremity was more affected during declined walking compared to inclined walking based on the number of significant differences observed in each inclination angle. The PFS was found increased with the increase of surface inclination. Conclusions: The findings could provide a new insight on the relationship of joint reaction forces and strain parameter in response to the incline and decline walking. It would benefit in providing a better precaution that should be considered during hiking activity, especially in medial-lateral direction in order to prevent injury or fall risk.
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