Salmiah Kasolang

Viscosity measurement in thin lubricant films using shear ultrasonic reflection

When a shear ultrasonic wave is incident on a solid and liquid boundary, the proportion that is reflected depends on the liquid viscosity. This is the basis for some instruments for on-line measurement of bulk liquid viscosity. In machine elements, the lubricant is usually present in a thin layer between two rubbing solid surfaces. The thin film has a different response to an ultrasonic shear wave than liquid in bulk. In this work, this response is investigated with the aim of measuring viscosity in situ in a lubricating film. The proportion of the wave reflected at a thin layer depends on the layer stiffness. A shear wave is reflected by the shear stiffness of the thin layer. For a thin viscous liquid layer, the stiffness is a complex quantity dependent on the viscosity, wave frequency, and film thickness. This stiffness is incorporated into a quasi-static spring model of ultrasonic reflection. In this way, the viscosity can be determined from shear-wave reflection if the oil-film thickness is known. The approach has been experimentally evaluated on some static oil film between Perspex plates. Predictions of the spring model gave good measurement up to layer thicknesses of around 15 μm. For thicker layers, the shear stiffness reduces to such an extent that almost all the wave is reflected and the difference associated with the layer response is hard to distinguish from background noise.

Observations of Film Thickness Profile and Cavitation Around a Journal Bearing Circumference

The film formation in a journal bearing and the extent of the cavitated region is an important contribution to load carrying capacity. In the present work, an ultrasonic method has been used to measure the film thickness profile around the circumference of an operating journal bearing. The reflection of an ultrasonic pulse at an oil layer can be used to determine the film thickness. A transducer was mounted inside a 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 enabled the full film thickness profile to be established. In the converging region the predicted film shape agrees well with predictions from classical lubrication theory. When cavitation occurs, the presence of oil-air and aluminum-air interfaces disrupts the ultrasonic signal. Evidence of cavitation appearance is very clear from the measurement results. The minimum film thickness, the attitude angle, and the onset of cavitation are compared with theoretical solutions.

Review study of developing an integrated TQM with LM framework model in Malaysian automotive industry

Purpose – The purpose of this paper is to investigate the origin and evolution of total quality management (TQM) and lean manufacturing (LM) in the automotive industry globally and specifically in Malaysia; and selective studies on effective performance measurement for future integration of TQM and LM. The paper examines critical success and failure factors of the implementation stage based on established quality criteria, such as in the Deming Prize Award, Malaysian Prime Minister Award, ISO/TS16949, Malcolm Baldrige National Quality Award, SAEJ4001 and Toyota Production System.Design/methodology/approach – The paper takes the form of a review of the literature on TQM and LM, utilizing journal articles, reports, books and theses.Findings – Based on reviewed papers, it was noted that TQM and LM originate from Japan. TQM started from a Company Wide Quality Control Program initiated by Deming, while LM originated from the Toyota Production System. Both terms were coined by the west for global acceptance in ...

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.

Flexural response of nanoclay-modified epoxy polymers

Abstract Epoxy resin is one of the most common polymer matrices, used in a wide range of applications. Cured epoxy exhibits brittle behaviour and low fracture toughness when subjected to mechanical loadings. The aim of this work was to study the effect of nanoclay on the flexural stress-strain response and flexural properties of Epikote 828 and aerospace grade-Cycom 977 polymers. Three-point bending tests were conducted on two polymer nanocomposite systems which contained 1-5 wt-% montmorillonite nanoclays. The white clay powder used in this study had a mean dry particle size of 8-10 μm before the mechanical stirring or milling process was performed. It was found that the slope of the stress-strain curves increased with increasing nanoclay content. This indicates that nanoclay enhanced the flexural modulus of the epoxy. The results showed that the degree of reinforcement depends on the degree of nanoparticles dispersion in the epoxy.

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.

Effect of Carbon Fibre Ratio to the Impact Properties of Hybrid Kenaf/Carbon Fibre Reinforced Epoxy Composites

Effects of the incorporation of untreated and treated hybrid kenaf/carbon fibre reinforced epoxy composites on the impact properties were studied. Hybrid kenaf/carbon fibres and thermoset matrices were hand-laid up and characterized in terms of its mechanical properties. The kenaf fibres were alkali treated whilst the carbon fibres were gamma radiation treated before use as reinforcement in the epoxy resin matrix. The reinforcing effects of kenaf hybridized with carbon fibre in epoxy composites were evaluated at various fibre loadings with overall fibre contents 20 wt%. Hybrid composites with different ratios of kenaf fibre : carbon fibre ; 0.9:0.1, 0.8:0.2, 0.7:0.3 and 0.6:0.4 were prepared. Impact tests of untreated and treated hybrid kenaf/carbon fibres were performed. The fractured surfaces of these composites were investigated by using scanning electron microscopic technique (SEM) to determine the interfacial bonding between the matrix and the fibre reinforcement. It was found that the treated hybrid composites increased the impact strength by 26% compared to the untreated ones.

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.

Characteristics of swirl effervescent atomizer spray angle

In the application of sprays produced by an atomizer, spray angle is one of key performance parameters. A larger spray angle is often required in providing a better spray dispersion. Swirl effervescent atomizer is one of the existing atomizers with the capability to produce a large spray angle. The formation of spray angle from this atomizer however is hardly understood. A newly-designed swirl effervescent atomizer was developed and tested with different swirl-generating vane angle in order to understand the swirl intensity effect on the spray angle. Experiments were carried out based on a cold flow test approach using water as the working fluid and nitrogen gas as the atomizing agent. High-speed shadowgraph technique was deployed to record the resultant sprays produced. Video recordings, acquired using a high-speed video camera, were converted to a sequence of images for further analysis using an image processing software. It was found that the spray angle increases with the swirl-generating vane angle. Specifically, the spray angle shows an abrupt increase for the case of swirl-generating vane angle changing from 30° to 45° but visualizes only a gradual increase in the case of swirl-generating vane angle changing from 45° to 60°.