Sylvester Abanteriba

Development of strategic international industry links to promote undergraduate vocational training and postgraduate research programmes

After centuries of protectionism in international trade, the course is inexorably set for trade amongst nations without borders. More and more countries are joining the World Trade Organization and companies are repositioning themselves for the conduct of their activities in an environment free from physical borders and national legislative restrictions. Commercial activity is as old as humanity itself and touches every aspect of human endeavour. The raison d’être for academic institutions, which provide skills training for the labour force of the community of nations, lies, to a large extent, in fulfilling the requirements of commercial activity. Any profound change in the manner in which commerce is conducted, logically, requires an equally profound change in the philosophy of developing the skills of the labour force. This paper therefore discusses the challenges which academic institutions face in restructuring their curricula to meet the demands of the globalized economy of the future. The paper describes the general principles necessary to develop the attributes of a globally employable graduate and reports, in particular, on activities already being undertaken by the Royal Melbourne Institute of Technology (RMIT), in association with industry partners within and outside Australia to meet these challenges. The prime mover of these activities is a programme called the RMIT International Industry Experience and Research Program (RIIERP), which was established in 1992 by the author.

Status of surface modification techniques for artificial hip implants

Abstract Surface modification techniques have been developed significantly in the last couple of decades for enhanced tribological performance of artificial hip implants. Surface modification techniques improve biological, chemical and mechanical properties of implant surfaces. Some of the most effective techniques, namely surface texturing, surface coating, and surface grafting, are applied to reduce the friction and wear of artificial implants. This article reviews the status of the developments of surface modification techniques and their effects on commonly used artificial joint implants. This study focused only on artificial hip joint prostheses research of the last 10 years. A total of 27 articles were critically reviewed and categorized according to surface modification technique. The literature reveals that modified surfaces exhibit reduced friction and enhanced wear resistance of the contact surfaces. However, the wear rates are still noticeable in case of surface texturing and surface coating. The associated vortex flow aids to release entrapped wear debris and thus increase the wear particles generation in case of textured surfaces. The earlier delamination of coating materials due to poor adhesion and graphitization transformation has limited the use of coating techniques. Moreover, the produced wear debris has adverse effects on biological fluid. Conversely, the surface grafting technique provides phospholipid like layer that exhibited lower friction and almost zero wear rates even after a longer period of friction and wear test. The findings suggest that further investigations are required to identify the role of surface grafting on film formation and heat resistance ability under physiological hip joint conditions for improved performance and longevity of hip implants.

The Development of Exhaust Surface Temperature Models for 3D CFD Vehicle Thermal Management Simulations Part 1 - General Exhaust Configurations

The thermal prediction of a vehicle under-body environment is of high importance in the design, optimization and management of vehicle power systems. Within the pre-development phase of a vehicles production process, it is important to understand and determine regions of high thermally induced stress within critical under-body components. Therefore allowing engineers to modify the design or alter component material characteristics before the manufacture of hardware. As the exhaust system is one of the primary heat sources in a vehicles under-body environment, it is vital to predict the thermal fluctuation of surface temperatures along corresponding exhaust components in order to achieve the correct thermal representation of the overall under-body heat transfer.

On the impact of fine filtration on spectrometric oil analysis and inductive wear debris sensors

Spectrometric oil analysis has been a popular technique used by oil analysis laboratories to determine the concentration of elements in an oil sample. The primary application of this technique has been the identification of fine wear in lubricated systems as an indicator of abnormal wear in order to prevent failure. It has also found some use for monitoring contaminants and fluid additives. While the literature has varying accounts of the effectiveness of this technique for machinery condition monitoring purposes, the introduction of fine filtration to many modern machines has profound implications for the effectiveness of spectrometric oil analysis. This paper will assess the effectiveness of spectrometric oil analysis in a fine filtered system and compare it with the results from an inductive wear debris sensor. The inductive wear debris sensor is a relatively new sensor for detecting abnormal wear in recirculating lubrication systems. A combination of experimental data and aircraft data is presented.

Determining inductive sensor wear debris limits for rolling contact fatigue of bearings

A relatively recent development for the condition monitoring of oil-wetted machinery has been the in-line full-flow inductive wear debris sensor (hereafter referred to as inductive wear debris sensors). These sensors detect a disturbance to a magnetic field caused by metallic wear debris shed from deteriorating dynamic components that is entrained in the lubricant. Applications for these sensors currently include (but are not limited to) aviation machinery, wind-turbine generators, marine propulsion systems, and locomotives. Inductive wear debris sensors can distinguish between ferromagnetic and nonferromagnetic particles as well as providing size and other related information. One of the primary advantages of this sensor type is that the detectable size range is broad and may be used to track the progress of an incipient failure such as the rolling contact fatigue of a bearing or gear as it occurs. One aspect that has received little attention in the literature is the methodology for determining a suitable limit for a particular application. Limits are a critically important aspect of machinery condition monitoring and need to be established by a robust and reliable method otherwise unnecessary maintenance can occur or an incipient fault may be missed. This paper describes a generic method for determining a physically meaningful debris limit for a deteriorating rolling element bearing when utilizing an inductive wear debris sensor.

An innovative approach to race track simulations for vehicle thermal management

Within the pre-development phase of a vehicle validation process, the role of computational simulation is becoming increasingly prominent in efforts to ensure thermal safety. This gain in popularity has resulted from the cost and time advantages that simulation has compared to experimental testing. Additionally many of these early concepts cannot be validated through experimental means due to the lack of hardware, and must be evaluated via numerical methods. The Race Track Simulation (RTS) can be considered as the final frontier for vehicle thermal management techniques, and to date no coherent method has been published which provides an efficient means of numerically modeling the temperature behavior of components without the dependency on statistical experimental data. The following investigation will explore an innovative methodology which utilizes a conventional method of simulation whilst integrating multiple 3-Dimensional CFD solutions which are interpolated to match a derived moving average profile. New meshing techniques in combination with the integrated use of a 1-Dimensional transient exhaust prediction tool facilitate higher turn-around times for dynamic vehicle conditions. The experimental data consisted of a test vehicle conducting several laps through the Nuerburg-ring whilst acquiring temperature data on a wide range of underbody components. Excluding the warm-up phase, a single lap simulation was conducted to evaluate the proposed methodology. A fair correlation was achieved between the simulation results and experimental data considering the time advantages of the methodology. Areas of discrepancy can be accounted for by the proposed 1-way coupling scheme and overcompensation of the component temperatures within CFD models.

The Development of Turbine Volute Surface Temperature Models for 3D CFD Vehicle Thermal Management Simulations: Part 3: Exhaust Radial Turbine Volute Systems

Modern exhaust systems contain not only a piping network to transport hot gas from the engine to the atmosphere, but also functional components such as the catalytic converter and turbocharger. The turbocharger is common place in the automotive industry due to their capability to increase the specific power output of reciprocating engines. As the exhaust system is a main heat source for the under body of the vehicle and the turbocharger is located within the engine bay, it is imperative that accurate surface temperatures are achieved. A study by K. Haehndel [1] implemented a 1D fluid stream as a replacement to solving 3D fluid dynamics of the internal exhaust flow. To incorporate the 3D effects of internal fluid flow, augmented Nusselt correlations were used to produce heat transfer coefficients. It was found that the developed correlations for the exhaust system did not adequately represent the heat transfer of the turbocharger. This paper addresses the fluid flow phenomena present in the turbine volute and applies augmented Nusselt correlations to accurately represent the heat transfer coefficients of the internal volute surface. Due to the broad range of operating conditions that are applicable to the turbocharger and the varied states of fluid flow that occur, algorithms are used to apply the appropriate Nusslet correlations and augmentations. Furthermore, the turbocharger extracts enthalpy from the working fluid; therefore to accurately calculate surface temperatures of downstream components and that of the turbocharger itself, an energy extraction model is used. Validation was conducted with four vehicle configurations. The hot-end of each configuration was aimed to be distinctly different to test the robustness of the prediction model. A tolerance range of +50/-20K was used for the study, however temperature differences were generally well within the tolerance range.

A Numerical Investigation of Dampening Dynamic Profiles for the Application in Transient Vehicle Thermal Management Simulations

As computational methodologies become more integrated into industrial vehicle pre-development processes the potential for high transient vehicle thermal simulations is evident. This can also been seen in conjunction with the strong rise in computing power, which ultimately has supported many automotive manufactures in attempting non-steady simulation conditions.The following investigation aims at exploring an efficient means of utilizing the new rise in computing resources by resolving high time-dependent boundary conditions through a series of averaging methodologies. Through understanding the sensitivities associated with dynamic component temperature changes, optimised boundary conditions can be implemented to dampen irrelevant input frequencies whilst maintaining thermally critical velocity gradients.A sub-module derived from real vehicle geometry was utilised to evaluate a series of alternative averaging schemes (consisting of steady-state CFD points) in comparison to full CFD transient conditions. The size and simplicity of the model additionally allowed for an easy transition to the heavy computationally demanding unsteady conditions. The input data for both averaging schemes and full transient conditions were derived from the real vehicle driving profiles experimentally obtained on the Nuerburgring test track.Qualitative analysis was conducted between the alternative schemes and full transient data in order to isolate the effects of dampening boundary conditions on consequent component temperatures. It was found that a weighted moving average can be optimal in resolving the high frequency changes whilst maintaining the average energy balance across under body components. The reactivity of the averaging schemes was dependent on the sampling rates in combination with the process of neutralising the inherent lag effects. Both these parameters had a significant effect on the time dependent results.In order to isolate the effectiveness of the averaging schemes on the “warm-up phase”, multiple laps were conducted to locate the point at which temperature stabilisation occurs. Additionally the effect of incorrect initial component temperature was explored through evaluating the time taken to thermal stabilisation. It was found that under differing thermal conditions the time taken to thermal stabilisation was relatively constant regardless of the initialisation temperature.The investigation explored the influence of improving the simulation accuracy by increasing the quantity of steady-state CFD points in locations of high velocity amplitudes over a short time period. Additionally the opposite was explored in regions of low velocity amplitude, in extended time phase. A relationship was found between the velocity gradient and the quantity of steady-state CFD points for component temperature. Through the findings of the investigation a Fourier type algorithm was exploited to further improve turnover efficiencies.

Electric discharge damage in aircraft propulsion bearings

Rolling contact fatigue (RCF) is a common failure mode for rolling element bearings, however evidence of precursor failure modes or initiators can be lost or obscured by the subsequent severe damage caused by RCF. Although electric discharge damage (EDD) is not normally associated with rolling element bearings in aviation propulsion applications, it can occur and may not be instantly recognisable. Unlike factors such as lubricant cleanliness or misalignment, EDD does not normally form part of the life prediction of aviation propulsion rolling element bearings. Early identification of EDD and subsequent mitigation or elimination is, therefore, essential to prevent significant reduction in life or failure of rolling element bearings. This paper will review the phenomenon of EDD and discuss several recent examples observed in aviation propulsion systems.

A Literature Review of Seating and Body Angles for Non-driving Secondary Activities in Autonomous Driving Vehicles

It is envisioned that the development of fully autonomous driving technology would allow future drivers to participate/engage in secondary activities other than the driving task. To undertake these non-driving secondary activities, the driver would need to be seated in a position that is different to the conventional driving position. In this study, a survey of scientific literature in the field of the relevant secondary activities, the associated seating positions, seating and body angles are being conducted by referring to 18 different sources published up to 2017. The aim of this study is to find out commonly used seat angles for different secondary activities and their seating positions. There is a current lack of literature specifically for seating positions of non-driving secondary activities, hence the research field was extended to consider a range of similar seating including office chairs, passenger seats in trains and aircraft, massage chairs, and lounge chairs among others.