Mohamad Ali Ahmad

Preliminary Study of Dry Sliding Wear in Kenaf Epoxy and Carbon Epoxy Composites

This paper presents an experimental investigation carried out to compare specific wear rate and surface morphology between Kenaf Epoxy Composite (KEC) and Carbon Fiber Reinforced Plastic (CFRP). Wear tests were carried out using Abrasion Resistance Tester (TR-600) in dry sliding conditions. These tests were performed at room temperature with different applied loads (5, 20 and 30N) and sliding velocity of 1.4m/s. Surface morphology of both materials was also examined before and after each test using an optical 3D surface measurement device. From the wear test, it was observed that the wear characteristics of KEC are comparative to those of CFRP. It was also found that the morphology of worn material composites in both cases exhibits a similar trend. This is a preliminary test for a future work on the enhancement of Kenaf Composites and the application.

The Effect of Oil Supply Pressure on the Circumferential Pressure Profile in Hydrodynamic Journal Bearing

In hydrodynamic lubrication, the pressure condition of the fluid is critical to ensure good performance of the lubricated machine elements such as journal bearings. In the present study, an experimental work was conducted to determine the effect of oil supply pressure on pressure profile around the circumference of a journal bearing. A journal diameter of 100mm with a ½ length-to-diameter ratio was used. The oil supply pressure was set at three different values (0.3, 0.5, 0.7 Mpa) and the circumferential pressure results for 400, 600 and 800 RPM at different radial loads were obtained. It was observed that the maximum pressure values were affected by changes in oil supply pressure.

Dry Sliding Wear of Oil Palm Empty Fruit Bunch (OPEFB) Epoxy Composite

This paper presents an experimental study carried out to determine the effects of fibre size on the mass loss, specific wear rate, roughness, and temperature distribution of Oil Palm Empty Fruit Bunch (OPEFB) epoxy composites. These epoxy samples were produced by mixing raw OPEFB fibres with epoxy. The samples were prepared at different sizes of fibres (100, 125, 180 and 250µm). Wear tests in dry sliding condition was carried out using Abrasion Resistance Tester (TR-600. The wear tests were performed at room temperature with two different loads (10 and 30N) and at constant sliding velocity of 1.4m/s. Mass loss and specific wear rate values for the composite materials were obtained and roughness values before and after abrasion were recorded. Temperature changes during abrasion testing of the composite surfaces were also captured using Infrared Camera. The mass loss was significantly higher for the smallest fibre size (100µm) examined at 30N. At other fibre sizes, the mass loss values were relatively closed. Distribution and orientation of fibres are suspected to have influenced the trend observed in the results.

Viscosity profile measurement in journal bearing by shear ultrasonic reflection

In a journal bearing application, viscosity is a key property of the lubricant that affects bearing performance. Viscosity of the lubricant controls the film thickness established during an operation. In the present work, an ultrasonic method has been used to measure the viscosity profile around an operating journal bearing. The reflection coefficient profile around the journal was established. A transducer was mounted inside the hollow shaft and the signal passed through slip rings. The journal bearing was run at a series of loads and rotational speeds. The transducer continuously pulsed and received as it swept around the bush circumference. This has enabled the viscosity profile to be established. The technique introduced to measure viscosity in journal bearing achieved acceptable results in certain regions of the journal bearing flow.

Experimental Study of Oil Supply Pressure Effects on Bearing Friction in Hydrodynamic Lubrication

Journal bearing is widely applied in most of rotating machineries for transmission of large loads at mean speed of rotation. Friction caused by the shearing condition between journal, bearing and lubricant contribute to power loses in journal bearing system. In the present study, an experimental work was conducted to determine the effect of oil supply pressure on frictional force, friction coefficient and torque of a journal bearing. A journal diameter of 100 mm with a ½ length-to-diameter ratio was used. The oil supply pressure was set at three different values (0.3, 0.5, 0.7 MPa). Frictional force and friction coefficient results for 400, 600 and 800 RPM at different radial loads were obtained. It was observed that the change in oil supply pressure has affected the fluid frictional force and friction coefficient to some extent.

The effect of fiber treatment on abrasive wear properties of palm fiber reinforced epoxy composite

Oil palm industries generate at least 30 million tons of lignocellulosic biomass annually in the form of oil palm trunks (OPT), empty fruit bunches (EFB), oil palm fronds (OPF) and palm pressed fibres (PPF). The palm fiber is one of the natural fibers used as reinforcement in composite materials in order to decrease environmental issues and promotes utilization of renewable resources. This paper presents a study on the effect of alkaline treatment on wear properties of palm fiber reinforced epoxy resin composite. Abrasive wear testing was deployed to investigate the wear profile of the composite surfaces. Testing was carried out which focused on the effect of alkaline treatment to the palm fiber under different amounts of fiber loading i.e. 1 wt%, 3 wt%, 5 wt% and 7 wt%. The palm fibers were soaked into 6 % of alkaline solution or natrium hydroxide (NaOH) for 12 hours. The fiber was treated in order to remove amorphous materials such as hemicelluloses, lignins and pectins of the fiber. The wear test sampl...

Distribution TUA-CDIO element in learning outcome (LO5-LO9) for engineering subjects

The present study aims to explore the correlation of TUA (Teach, Use, Assess) and CDIO (Conceive-Design-Implement-Operate) implementation in the field of engineering education. Outcome Based Education (OBE) is adapted to identify and enhance the clarity of outcomes in a subject or course thought. To ensure that the target of OBE is well achieved, the CDIO is implemented and is analyzed through the introduction of a new concept, TUA. In this study, 32 subjects in the curriculum of Mechanical Engineering were selected for review and analysis in the distribution of TUA (Teach, Use, Assess) elements in the Learning Outcome Domains (LO) of LO5 to LO9. The outcome shows that in the aspect of teaching, the LO7 is used highly with a 35% percent score followed by LO5 and LO8 and LO9 having the lowest scores of 6% each. In the Use element, LO7 again takes the highest score of 27% and LO8 takes the lowest place with a score of 10%. As for the Assess element, the highest percentage of assessment is made based on LO5 with 31% and the lowest learning outcome assessed is LO8, 10%. A trend to be noted here is that LO8 is minimally adapted in all the TUA elements

Analysis of Transmission Fluid in Manual Diesel Engine by Ferrographic Technique

Condition monitoring techniques have been developed in the past two decades in order to predict and overcome the wear related damage progression in gear transmission systems. Ferrographic Technique (FT) is a microscopic analysis to identify the presence of material composition by characterizing particles concentration, type, size, distribution, and morphology. This technique is part of a Predictive Maintenance (PdM) program to avoid a major failure in machine systems. In the present study, analysis of wear characterization in diesel engine by Ferrographic Technique was conducted. Transmission fluid samples were collected from intercity bus and analyzed using Ferrogram Maker (FM-III). Optical microscopy and Predict Chart were used to characterize and identify sample in where groups. It was observed that the corrosive and black oxide wear type were major findings in all samples tested.

The Effects of Oil Groove Position on Torque and Frictional Force in Hydrodynamic Journal Bearing

Axial groove is a common supply method of distributing lubricant within a journal bearing. Lubricant is generally fed at a specific supply pressure to ensure that the journal and the bearing surface are separated. Shearing action between lubricant and bearing parts creates frictions which contribute to power loss in journal bearing. In the present study, an experimental work was conducted to determine the effect of oil groove location on torque and frictional force in hydrodynamic journal bearing. A journal diameter of 100mm with a 12 length-to-diameter ratio was used. The oil supply pressure was set at 0.20 to 0.25 MPa. The groove was positioned at 3 different locations namely 00, +150and +300. Measurements of torque and frictional force were obtained for speed values of 300, 500 and 800 RPM at different radial loads. It was observed that the change in oil groove location has affected the fluid frictional force and friction coefficient to some extent.