Predictive Modelling of Creep Crack Initiation and Growth using Extended Finite Element Method (XFEM)

In this study, a numerical strategy for predictive modelling of creep in tension tests for the rectangular plate with a single crack and CT-specimen based on the extended finite element method (XFEM) will be described in detail. A model of creep fracture initiation and creep crack growth (CCG) is developed, while the XFEM is employed to spots located inside the finite element for the purpose of predicting crack potential and propagation. In order to characterize the creep fracture initiation, identification of C(t)-integral formula is conducted. In addition, XFEM and analytical solutions are also analyzed to look at the connection of C(t)-integral with time for a rectangular plate with a single crack under plane stress conditions. An illustration showing the se-quence of stress distribution and displacement contour plots are also being presented. The stresses and displacements spread throughout the crack path have also been determined using CT-specimens. In addition, the creep cracks growth length with normalized time and the creep crack growth rate with the C(t)-integral are predicted to be related, indicating that the numerical results are in good accord with the experimental results

Studies on Flame Retardants on Malaysian Coir Fiber

In this study to the effect of the utilization of urea and diammonium phosphate as fire retardant on Malaysian coir fiber was evaluated. Flammability and thermogravimetric analysis (TGA) tests were used to evaluate the fire retardancy. Weight loss and percentage of mass residue were used as a measure from the results of flammability and TGA, respectively. The results revealed the effectiveness of using urea and diammonium phosphate as fire retardant for Malaysian coir fiber. However, for the samples treated with retardant high concentration the weight loss is not significant with the time of dipping treatment. This indicates that the just dip application for the fire retardant of higher concentration is sufficient

Relationship between Driver's Dynamic Pressure Distribution with their Anthropometric Variables on Car Seat under Paved Road

Driving is a task that requires physical and emotional demands of the driver to control the car while sitting. The driver's condition may be affect due to this repetitive driving task, which can be determined through the performance of alertness, signs of discomfort as well as fatigue level experience by the driver. Past studies showed that anthropometric variable is one of the factor in determining human's performance while performing an activity. However, there is still a lack of systematic explanation on how it relates to driving activity under different road conditions. Thus, this research objectives to determine the relationship between selected driver's anthropometric variables with dynamic pressure distribution experienced on the car seat while driving on paved road under normal driving task. A total of 44 subjects participated in this study. Tactilus pressure sensor was used to record the pattern of pressure distribution while driving. Based on the finding, there is a mild correlation with r =0.61 and (R2 = 0.38) between dynamic pressure on the right thigh with height and weight of the subject. The study revealed that nearly 40 percent of the variance in the dynamic pressure on the left thigh is predictable from the height and weight of the subject

Quality of life and its demographic predictors among workers at a plastic factory in Malaysia: a cross-sectional study

Quality of life (QOL) is an individualized measure that reflects a person’s subjective feelings towards the different aspects of his or her life and incorporates them into his overall health evaluation. The WHOQOL-BREF is a QOL measurement tool that has been validated in worldwide and local studies, with good reliability and sensitivity. WHOQOL-BREF questionnaire was used to evaluate the QOL of 89 workers at a plastic factory in Selangor, Malaysia. These were compared using t-test and Spearman’s bivariate correlation test to assess for significant correlations and predictors of performance in the different domains. The performance of the sample, both overall and for individual domains, was significantly lower than reported in previous studies. Local workers, highly educated workers, workers with shorter employment, and workers who did not take overtime performed significantly better than their respective counterparts. Also, lower education, foreign nationality, longer employment at the factory, overtime, and crushing jobs were associated with lower QOL scores. Studies evaluating QOL in industrial workers in Malaysia are scarce. Our sample is more diverse than the previous similar studies from Malaysia, and hence it offers new insights into the QOL of plastic industrial workers in the country

Impak dari program mahasiswa ke masyarakat (M2M) kepada pelajar dan komuniti dalam penyebaran ilmu risiko ergonomik

Graduan yang berkualiti bukan sahaja berjaya dalam akademik, tetapi juga sahsiahnya, Sesuatu program universiti pada masa kini tidak hanya terarah kepada pencapaian akademik semata-mata. Hasil program dalam sesuatu program dalam masa sekarang juga menimbangkan atribut berkaitan komunikasi sama ada dengan ahli atau masyarakat dan juga kerja berkumpulan. Artikel ini mengkaji peranan mahasiswa dalam menyebarkan ilmu yang dipelajari di dalam kelas kepada masyarakat atau komuniti di luar. Masyarakat ketika ini bergelumang dengan pelbagai isu masalah kesihatan dan juga keselamatan bukan sahaja di luar rumah malahan juga di rumah sendiri. Oleh itu, pendekatan memperkasakan masyarakat melibatkan program kesedaran dalam penjagaan kesihatan dan keselamatan perlu dilakukan. Kajian ini melibatkan program perkongsian ilmu dari sebahagian mahasiswa Tahun Akhir Program Kejuruteraan Mekanikal kepada segelintir masyarakat dalam pelbagai peringkat berkenaan isu ergonomik. Kaedah temubual antara kumpulan pelajar dan komuniti merupakan kaedah utama dalam program ini. Hasil program ini menunjukkan, tahap kesedaran masyarakat bertambah baik melalui perkongsian ilmu risiko ergonomik. Selain itu, pemahaman pelajar juga bertambah baik melalui program ini. Kajian ini menunjukkan program yang berkaitan amalan merentasi pelbagai komuniti dapat membantu mahasiswa dalam memastikan pemahaman yang lebih baik dapat dicapai dalam sesuatu perkara

Assessing the levels of traffic noise in selected Schools in Bandar Baru Bangi

Traffic noise during school hours can disrupt students’ learning focus especially in the classroom and can affect communication between teachers and students. This study was conducted to asses traffic noise levels for four selected schools along few main roads in Bandar Baru Bangi and analyse the data using the guideline recommended by the Malaysia Department of Environment (DOE). Data was collected using 01dB SOLO sound level meters using the decibel A-weighted (dBA) for LAeq , L10 , L50 , L90 , LAeqmax dan LAeqmin . The measurement was collected during the respective peak hour on school days which are 7.00am -9.00am for morning session, 12.00pm -2.00pm for noon and 5.00pm -7.00pm for evening session. The measured noise then analysed and compared with the recommended standards set by the DOE. From the measurement, it was found that traffic near the Greenview Islamic International School recorded up to 76.3dB(A) for LAeq, 110.3 dB(A) for LAmax , L10 = 78.4 dB(A) and L90 = 67.6 dB(A) during the period of 12.00pm to 1.00pm. All the measured traffic noise at the respective school also logged a high noise level for their LAeq measurement. In conclusion, the study showed that the traffic noise level pollution experience by the schools along the main roads in Bandar Baru Bangi district were alarming which are exceeding the recommendation from DOE. This finding can help policymakers and stakeholders used as reference in sense of noise pollution management for better acoustics comfort at school area

Evaluation of All-Round Modular Scaffolding (ARMS) type Scaffold by using BS1139 Standards for Industries

Scaffolds can be categorised into access scaffolds and support scaffolds based on its functions: access scaffolds and support scaffolds. Regardless, both are only consent to be used when it follows requirement set forth by the government in order to protect the workers’ safety and health. Due to increased demand for scaffolds manufacturers try to compete with each other by developing various type and sizes of scaffolds. Unfortunately, the usage of these modern scaffolds such as All-Round Modular Scaffoldings are rather limited due to its deviations from the BS 1139 standards. This study aims to determine the distribution force on the All-Round Modular Scaffolding determine its suitable duty category based on the BS1139 guidelines. Standard parts of ARMS from manufacturer was used to build one storey x 1 bay (sizing 3 m x 3 m) structure and was assembled by authorised and professional contractor. The structure was then put through load test. The load was placed on top of the working platform and the deflection of the components was measured. The findings reveal that the structure as well as the individual platform can support loads up to 500 kg with no crack or permanent deformation observed after the test. By referring the BS1139 standards, the All-Round Modular Scaffolding is surpassing the requirement for general and heavy-duty scaffold with distributed load on platform recorded to be 2.67 kN/m2 and concluded that the additional length of the components does not compromise the working purpose of the scaffolds

Evaluation of occupational noise exposure in a plastic manufacturing industry : a case study

Industrial workers need a safe working environment to ensure their wellbeing is protected while performing tasks. Occupational noise is one of the most prevalent problems in industries due to nature of the industry. Therefore, this paper aimed to evaluate the occupational noise exposure in one of the plastic factories in Klang Valley, Malaysia. Noise measurement has been done in all production lines, crushing department, packaging department and officers’ area. The noise measurements were taken 1 to 3 metres from the source of noise at several points for each line and departments using sound level meter. Average noise level at all measurement location noted LAeq less than 80 dBA, except one point in line B and the crushing area. The packaging department recorded the lowest noise level, with LAeq 64.8 dBA and LAmax of 69.2 dBA. While, the crushing department is the noisiest area in the factory, with LAmax 105 dBA and LAeq 100.9 dBA. The average noise level at majority location in the factory is less than 80 dBA which means it is at a safe range. The workers do not need any personal hearing protection equipment during working, which was according to the Occupational Safety & Health (Noise Exposure) Regulations 2019 noise regulations in Malaysia, except the crushing area only. In conclusion, evaluation of noise exposure in each section can provide a good understanding of the occupational noise level experienced by different workers at different departments. It can help the management to strategize and plan the noise control approach, especially at the area that may have risk of hearing loss for their workers

Predictive modelling of creep crack initiation and growth using Extended Finite Element Method (XFEM)

In this study, a numerical strategy for predictive modelling of creep in tension tests for the rectangular plate with a single crack and CT specimen based on the extended finite element method (XFEM) will be described in detail. A model of creep fracture initiation and creep crack growth (CCG) is developed, while the XFEM is employed to spots located inside the finite element for the purpose of predicting crack potential and propagation. In order to characterize the creep fracture initiation, identification of C(t)-integral formula is conducted. In addition, XFEM and analytical solutions are also analyzed to look at the connection of C(t)-integral with time for a rectangular plate with a single crack under plane stress conditions. An illustration showing the sequence of stress distribution and displacement contour plots are also being presented. The stresses and displacements spread throughout the crack path have also been determined using CT specimens. In addition, the creep cracks growth length with normalized time and the creep crack growth rate with the C(t)-integral are predicted to be related, indicating that the numerical results are in good accord with the experimental results