Nor Amalina Muhayudin
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Preferred name
Nor Amalina Muhayudin
Official Name
Nor Amalina, Muhayudin
Alternative Name
Muhayudin, Nor Amalina
Main Affiliation
Researcher ID
FQJ-2893-2022

Research Output

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Benchmarking artifact of selective laser sintering (SLS) components fabricated with flexible and rigid polymers

2025-01 , Hor Zian Shen , Nor Amalina Muhayudin , Tien-Dat Hoang , Khairul Salleh Basaruddin , Nur Liyana Tajul Lile , Shah Fenner Khan Mohamad Khan

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.

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Development and evaluation of synthetic paediatric mid-thoracic spine model for Scoliosis assessment

2021 , Nor Amalina Muhayudin

Scoliosis is a condition with abnormal spine lateral curvature that is affecting people of all ages but is the most common in children. Most of the studies that had investigated scoliosis-related subjects were using animal and adult spines; thus, in reality, they may not be representing the paediatric spine, as the paediatric spine is not the same and should not be treated as a miniature version of an adult spine. Therefore, the aim of this study is to develop a synthetic paediatric spine model and to evaluate the mechanical behaviour of the paediatric spine in comparison with adult and animal spines. The section of the spine selected for this research was the T4 to T8 mid-thoracic region. As the spine is such a complex structure, the fabrication process of the synthetic model was simplified by focusing on three main components; vertebra, intervertebral disc and spinal ligaments. The expandable PU foam was selected to replicate the trabecular bone. Meanwhile, the lightweight silicone materials were selected to model the intervertebral disc by replicating the nucleus pulposus, while the monothane® materials were used to model the annulus fibrosus. Additionally, the composite materials consisting of fibre tape and plastic silicone were used to represent the spinal ligaments. The synthetic paediatric spine was fabricated as a scaled-up model of the paediatric spine by 200%. Biomechanical tests were conducted to measure the range of motion (ROM) and non-linearity of the sigmoidal curves at six DOF, with moments ranging from between ±1 to ±4 Nm. The results were compared with the data reported on porcine spines (retrieved from prior literature) and an analogue adult lumbar spine (Sawbones®). The differences of 18% and 3%, respectively, were found in lateral bending and axial rotation of the synthetic paediatric spine, as compared to the porcine spine. Moreover, the flexion extension was observed to differ by 45%, but the ROM was still within the range. Similar sigmoidal curves were observed for all six DOF when compared to the analogue adult lumbar spine, where the flexion extension and axial rotation tended to be more linear. The paediatric ROM was measured using a validated paediatric FE model at ±0.5 Nm moment (i.e. paediatric loading) to determine the moment required by the synthetic paediatric spine to obtain the paediatric ROM. The results showed that in flexion extension, the paediatric ROM was closer to ±3 Nm moment, while in the lateral bending and axial rotation, the paediatric ROM was closer to ±2 Nm moment. The movements of the synthetic paediatric spine were found to be stiffer in the flexion extension but were more flexible in the lateral bending in comparison to the paediatric FE model. This was potentially due to the simplified design of the intervertebral disc, as well as the poor bonding between the disc and vertebrae. Despite that, the developed model showed promising results, hence suggested that the synthetic paediatric spine has the potential application as an alternative paediatric spine model. In the long term, this model could replace the animal and adult spines to investigate pathologies of the paediatric spine, such as scoliosis.

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Development of synthetic spine for biomechanical research: An overview

2021-10-25 , Nor Amalina Muhayudin , Khairul Salleh Basaruddin , Haniza Yazid , Ahmad Faizal Salleh

Human and animal cadaveric spines are the most common specimens used in biomechanical investigations. However, biological cadaveric spines come with a lot of disadvantages, which resulted in questionable reliability of the data obtained. This motivated the authors to look at the development of a working synthetic spine in motion segments because synthetic materials have been used widely to replace the cadaveric specimens especially for bone testing. The objective of this paper is to provide an overview of the current development of a working synthetic spine and why it is crucial to consider synthetic spine as another alternative specimens to replace human and animal cadaveric spines for biomechanical research. The development of synthetic spines studies in recent years showed a great potential to replicate the human cadaveric spine. Although some of the motions were quite stiff in comparison with human cadaveric motions, with further adjustment, the improved synthetic spine can potentially benefit and transform the spinal biomechanical investigations in the future.

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Evaluating compressive properties and morphology of expandable polyurethane foam for use in a synthetic paediatric spine

2020 , Nor Amalina Muhayudin , Khairul Salleh Basaruddin , Fiona McEvoy , Anthony Tansey

An expandable rigid PU foam can turns into complex shapes, with a shell like structure on the outside and honeycomb structure on the inside, which can be easily shaped to a vertebra form. The present study aims to determine whether expandable rigid polyurethane foam was an appropriate substitute for rigid block polyurethane foam to model the trabecular bone. Static compression tests were performed to determine compressive moduli and yield stresses on three polyurethane foam densities namely 0.16 g/cm3, 0.24 g/cm3 and 0.42 g/cm3. Morphology of the PU foams for all densities was also observed. The compressive modulus for 0.16 g/cm3 and 0.24 g/cm3 were found varied from 40 to 43 MPa and 83 to 92 MPa while yield stress ranged from 2.1 to 2.3 MPa and 3.4 to 4.8 MPa respectively. As for 0.42 g/cm3, the compressive modulus and yield stress varied from 240 to 256 MPa and 38 to 40 MPa. Based on these results, the compressive modulus and yield stress of 0.24 g/cm3 compared favourably with rigid block PU foam and human cadavers presented in the literatures. Hence, the findings of this study could potentially be used in developing a synthetic vertebral trabecular bone of paediatric spine for biomechanical testing.

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Spine Deformity Assessment for Scoliosis Diagnostics Utilizing Image Processing Techniques: A Systematic Review

2023-10-01 , Amran N.N. , Khairul Salleh Basaruddin , Ijaz M.F. , Haniza Yazid , Nor Amalina Muhayudin , Shafriza Nisha Basah , Sulaiman A.R.

Spinal deformity refers to a range of disorders that are defined by anomalous curvature of the spine and may be classified as scoliosis, hypo/hyperlordosis, or hypo/hyperkyphosis. Among these, scoliosis stands out as the most common type of spinal deformity in human beings, and it can be distinguished by abnormal lateral spine curvature accompanied by axial rotation. Accurate identification of spinal deformity is crucial for a person’s diagnosis, and numerous assessment methods have been developed by researchers. Therefore, the present study aims to systematically review the recent works on spinal deformity assessment for scoliosis diagnosis utilizing image processing techniques. To gather relevant studies, a search strategy was conducted on three electronic databases (Scopus, ScienceDirect, and PubMed) between 2012 and 2022 using specific keywords and focusing on scoliosis cases. A total of 17 papers fully satisfied the established criteria and were extensively evaluated. Despite variations in methodological designs across the studies, all reviewed articles obtained quality ratings higher than satisfactory. Various diagnostic approaches have been employed, including artificial intelligence mechanisms, image processing, and scoliosis diagnosis systems. These approaches have the potential to save time and, more significantly, can reduce the incidence of human error. While all assessment methods have potential in scoliosis diagnosis, they possess several limitations that can be ameliorated in forthcoming studies. Therefore, the findings of this study may serve as guidelines for the development of a more accurate spinal deformity assessment method that can aid medical personnel in the real diagnosis of scoliosis.

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Finite element modelling of a synthetic paediatric spine for biomechanical investigation

2023 , Nor Amalina Muhayudin , Muhammad Farzik Ijaz , Khairul Salleh Basaruddin , Ruslizam Daud

Studies on paediatric spines commonly use human adult or immature porcine spines as specimens, because it is difficult to obtain actual paediatric specimens. There are quite obvious differences, such as geometry, size, bone morphology, and orientation of facet joint for these specimens, compared to paediatric spine. Hence, development of synthetic models that can behave similarly to actual paediatric spines, particularly in term of range of motion (ROM), could provide a significant contribution for paediatric spine research. This study aims to develop a synthetic paediatric spine using finite element modelling and evaluate the reliability of the model by comparing it with the experimental data under certain load conditions. The ROM of the paediatric spine was measured using a validated FE model at ±0.5 Nm moment in order to determine the moment required by the synthetic spine to achieve the same ROM. The results showed that the synthetic spine required two moments, ±2 Nm for lateral-bending and axial rotation, and ±3 Nm for flexion-extension, to obtain the paediatric ROM. The synthetic spine was shown to be stiffer in flexion-extension but more flexible in lateral bending than the paediatric FE model, possibly as a result of the intervertebral disc’s simplified shape and the disc’s weak bonding with the vertebrae. Nevertheless, the synthetic paediatric spine has promising potential in the future as an alternative paediatric spine model for biomechanical investigation of paediatric cases.

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