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Zaleha Mohamad
Universiti Tun Hussein Onn Malaysia (UTHM)
Civil Engineering, Building, Construction & Architecture Computer Science & IT Earth & Planetary Sciences Engineering Mechanical Engineering Transportation

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Effects of Percentage Fibre with Treated and Untreated on Sound AbsorptionProperties in Rubber Wood Fibre Composite Muhammad Hanafi Abd Rahman; Zaleha Mohamad
JSE Journal of Science and Engineering Vol. 1 No. 2 (2020): Journal of Science and Engineering
Publisher : LPPI Universitas Muhammadiyah Kalimantan Timur (UMKT)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30650/jse.v1i2.1637

Abstract

Current developments on natural fibre as sound absorption purpose have attracted researcher’s attention since sound pollution has been a threat to peoples. Hence, in this study, a fibrous acoustic material, which is rubber wood fibre, was used to determine acoustical properties. To achieve higher sound absorption coefficient (SAC) especially at low frequency, pre-treatment of the fibre is needed where in this study alkaline treatment was implemented. Three different percentages of fibre, namely 20%, 25% and 30% for non-treated and treated fibre were used to study the acoustical characteristic. Impedance tube method (ITM) was used to determine SAC. From the result, it has been found that SAC for fibre treated with alkaline was better than untreated fibre at low frequency. Alkaline treatment of the rubber wood fibre reduced the fibre diameter. More tortuous path and higher airflow resistance occurred since more fibre needed to reach the volume density of the sample. This work confirms by increasing rubber wood fibre content in the sample would also increase the acoustic performance and this has been proved where 30% of fibre sample mostly demonstrated better SAC compared to other fibre content for untreated and treated fibre and can be considered as sound absorption application
Crack Propagation Trajectory For Kenaf Fibre Composite Under Quasi Static Loading Nurul Alya Zahari; Zaleha Mohamad
JSE Journal of Science and Engineering Vol. 1 No. 2 (2020): Journal of Science and Engineering
Publisher : LPPI Universitas Muhammadiyah Kalimantan Timur (UMKT)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30650/jse.v1i2.1638

Abstract

The cracking of the composites are worthy the attention in order to expect in which manner of failure might occur. This matter should be not underestimated because of a safe structure may fail with even microscopic flaws. The crack propagation trajectory and effects of the hole in woven and non-woven fibre orientations for epoxy based kenaf composites under quasi static loading are investigated. The shape of the work specimens is square thin plate with thickness of 3 mm. There are two types of orientations of work specimen used which are the non-woven random and plain woven with 0° and 90° fibre orientation. These work specimens made by hand lay-up method. There are three setting conditions of the work specimen used in this research such as single edge crack, single edge crack with hole, and double edge crack with two holes. The experiments of tensile tests were carried out to determine the strength of the epoxy based kenaf composites. The specimens were subjected to a concentrated load at the upper edge and fixed at the lower edge. From the data attained, indicated that fibre orientation has a significant role in defining the ultimate tensile strength. The main objective of this research is to investigate the crack propagation trajectory for epoxy based kenaf composites under quasi static loading. It shows that from the results obtained, the crack trajectories for single edge crack is a straight line. However, the existence of the hole rearrange the stress or strain field. The crack will curved towards the hole. Meanwhile, for double edge cracks with two holes, the cracks move to the near hole. The cracks then reoriented horizontally as the cracks have reformed the stress distribution at each other’s tip. After that, the cracks then captivated again by the opposite holes and curved toward s the holes. It was found that there is no significant difference between the crack propagation for non-woven and woven fibre orientation samples.
The Sound Absorption Coefficient and Noise Reduction Coefficient of Rice Husk Silica Tan Ke Wei; Zaleha Mohamad
JSE Journal of Science and Engineering Vol. 1 No. 2 (2020): Journal of Science and Engineering
Publisher : LPPI Universitas Muhammadiyah Kalimantan Timur (UMKT)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30650/jse.v1i2.1640

Abstract

Efficient noise control is neccessary to be applied to reduce the sound pollution and obtain a comfortable life. Rice husk is one of the abandoned agriculture waste material that can obtained in a large quantity which have the potential in the application of sound absorber. Rice husk silica samples have been fabricated in various composition and thickness by using epoxy and methyl ethyl ketone peroxide (MEKP) as binder. Impedance tube testing and physical test are conducted to obtain the properties of rice husk silica. The result found that specimens with higher composition of rice husk silica and using MEKP as binder have the lowest density, highest porosity and give a better sound absorption coefficient. The increment of thickness can produce a greater sound absorption at lower frequency. The results also demonstrate 20mm is the best thickness for a greater noise reduction coefficient.
Co-Authors Muhammad Hanafi Abd Rahman Nurul Alya Zahari Tan Ke Wei