bluuebunny/crossref_metadata_2025 huggingface dataset:
Prediction of Transient Pressures in Polyethylene Pipes
Authors: Ellis J
Published: February 2007

Increasingly sophisticated numerical modelling techniques for the simulation of pipeline pressure transients have been developed over the past decades since the relatively widespread availability of digital computers. Introduction of new pipe materials, in particular plastics, has also taken place. These materials have mechanical characteristics that differ from those of more traditional pipe materials. To make the best use of numerical methods requires that mechanical behaviour and properties of plastics are well understood and documented. This paper describes how polyethylene pipes may differ in their response to pressure surge from that of other pipe materials. Numerical model developments are described which are aimed at producing a more accurate simulation of surge behaviour. In particular two ways in which polyethylene pipe behaviour departs from that of some other pipe materials are examined. One of these relates to the time-dependent modulus of the material and the other to the deformable nature of the cross-section which can result from its relatively high flexibility. Potential benefits of using polyethylene pipes are considered from a pressure surge viewpoint.
The Optimization of Dimensions of an Adjustable Mechanism for a Packaging Machine
Authors: Daadbin A , Sadek K S H
Published: February 2007

Mechanisms form the basic geometrical elements of many mechanical devices including automatic packaging machinery, typewriters, textile and printing machinery, and others. A mechanism typically is designed to create a desired motion of a rigid body relative to a reference member by the help of gears, cam systems or spatial linkages.

In flow pack machines a tube of wrapper containing the products moves with a uniform velocity, while the reciprocating heads move forward and backwards sealing different products. In an existing machine, these motions are produced by a rather complex mechanism involving cams and adjustable links.

The paper suggests replacing these cams by a suitable quick-return mechanism with a minimum number of adjustable links. The dimensions of this mechanism are optimized such that the motions produced are as near as possible to those obtained by the original cam mechanisms. The simplification can result in reduction in the mass of different components and existing forces in the mechanism.
Pressure Vessel Manufacture using the Chinese Ribbon Winding Technique
Authors: Zhu G , Jiang J , Wang Z , Moffat D G
Published: February 2007

During the past 20 years a technique has been developed in the People's Republic of China for manufacturing thick-walled pressure vessels using thin steel ribbons, helically wound under tension onto a thin inner steel core. The technique is described herein and the advantages claimed are outlined, together with brief descriptions of some related areas of development.
Developments in Fish Handling and Processing: An Engineering Perspective
Authors: Merritt J H
Published: February 2007

The engineer faces new challenges brought about by demands for improved fishery products and the need to make maximum use of available resources. In recent years, after a period of great expansion, important advances have been made in the handling and processing of fish. The wider application of modern techniques will enhance the position of fish as food.
A Study of Adhesion Between the Rails and Running Wheels on Main Lines: Results of Investigations by Slipping Adhesion Test Bogie
Authors: Nagase K
Published: February 2007

Many experiments have hitherto been made to analyse the adhesion between the rails and running wheels which affects the performance of rolling stock profoundly. However, most of such experiments have been made in laboratory rooms, and even those made on main lines have simply yielded a medley of data obtained at the spots of wheel slipping. The author constructed a ‘slipping adhesion test bogie’ designed upon a new idea of measuring the coefficient of adhesion continually while running and observed the state of adhesion on main lines. From the results thus obtained, the author discussed the state of adhesion, referring to the adhesion decreasing factors, derived the statistically processed coefficients and confirmed the utility of the test bogie.
Control of the Noise Environment for Passengers in Railway Vehicles
Authors: Hardy A E J , Jones R R K
Published: February 2007

Modern rolling stock is significantly quieter, both internally and externally, than previous designs of carriage on British Railways (BR). However, there remains scope for improvement on future builds of vehicle in order to provide a better acoustic environment for passengers. Attention needs to be given, in particular, to the shape of the sound spectrum. This paper discusses the acoustic characteristics which influence passenger comfort and the extent to which a satisfactory acoustic environment is achievable. Sources of internal noise are identified, and the mechanisms by which the sound energy enters the passenger areas are discussed. Measures which can be taken to influence these mechanisms, preferably at the design stage, are indicated.
Brake Modelling in Train Simulation Studies
Authors: Murtaza M A , Garg S B L
Published: February 2007

This paper deals with brake modelling as used in train simulation study. Accuracy of predictions depend on the type of model used and the numerical techniques used in finding the solution. The model described is based on analysis of a pneumatic train circuit through which braking demand is impressed on each vehicle of the train and analysis of the vehicle pneumatic circuit which senses braking demand and correspondingly develops brake cylinder pressure. The results are in good agreement with the experimental data. It is found that detailed and exhaustive modelling requires large amounts of computing time.
The automatic hydraulic ram—experimental results
Authors: Rennie L C , Bunt E A
Published: February 2007

Previously developed theory (1, 2) using compressible flow principles is applied to predict the performance of a commercially available ram. The results are compared with experimental values, agreement being satisfactory.
Information Systems for Use by Production Management in Smaller Manufacturing Enterprises
Authors: Muhlemann A P , Price D H R , Sharp J A , Afferson M , Andrews J K
Published: February 2007

This paper presents the results of a research project designed to investigate the possibilities of developing generic software for use by production management in smaller manufacturing enterprises (SME). This has exploited the latest development in fourth generation languages (4GLs).

A survey was carried out to establish the current state-of-the-art in computer assisted production management (CAPM) and to identify key areas to be included in the development. The results of this led to the inclusion of materials management, production planning (imaterials and resources), production progressing and costing as the basic cores in the system developed. The choice of 4GL was seen as a crucial factor to the success of the project. The wide availability of these meant that a formalized procedure needed to be developed to select that used by the project team: DAT AFIT DP4. To facilitate the generic nature of the software, and to contribute to its flexibility, a general model of the production process was constructed, built on control theory principles. The data models were based on this. The problems of identifying the functionality to be incorporated into the cores was overcome by the development of a process ‘template prototyping’ by which a structured stage-by-stage brainstorming framework was employed. The generic software developed has been field tested with collaborators in a variety of modes, including prototyping.
Temperature Rise in Hydraulic Systems
Authors: Bowns D E , Yang H
Published: February 2007

The heat released by losses in a hydraulic system can strongly affect its performance. Reduction in viscosity due to fluid temperature rise can increase leakage losses, in some cases to an unacceptable amount. This paper suggests approaches to the problem of assessing the temperature distribution in a hydraulic system by simulation and describes an experiment to correlate theoretical and observed behaviour. An interesting development of the work has been the simulation and experimental investigation of radiation effects under room temperature conditions. On the basis of the work it has been concluded that the radiation effects at the temperatures considered are far more significant than previously thought.
Installation Effects in Fan Systems
Authors: Bolton A N
Published: February 2007

The paper reviews some of the changes in fan aerodynamic, acoustic and vibration performance that can be attributed to interactions between a fan and the system in which it operates. The need for the recognition of the importance of installation effects by manufacturers, specifiers and users of fan systems is highlighted by reference to commercial, efficiency and safety aspects of fan systems. It is concluded that there is an urgent requirement for further research.
Exergy Analysis—A Different Perspective on Energy Part 1: The Concept of Exergy
Authors: McGovern J A
Published: February 2007

Exergy analysis is a technique at the forefront of applied thermodynamics research whereby systems that utilize energy are assessed in the light of the second law of thermodynamics. All forms of energy transfer and transport can be represented by equivalent exergy transfers which are, in fact, the quantities of work that could be produced from the same types of energy transfer or transport by perfect thermodynamic devices free to interact with a specified reference environment. Energy is conserved and this is a fundamental physical law. Whereas conventional energy analyses can only account for where energy is distributed, or lost from systems of interest, exergy analysis can highlight where it is used inefficiently. This paper describes and develops the exergy analysis concept. The exergy transfers associated with various types of energy transfer and transport are defined and an ‘exergy analysis toolbox’ is described. In Part 2 of the paper a universal rational efficiency is described and a number of worked examples are presented to illustrate the application of exergy analysis. Some of the present limitations of the technique and areas for future development are described.
Total Quality and ‘High Wire’ Performance
Authors: Odgers G D W
Published: February 2007

Reviews the difficulties experienced by British Telecom since privatization in 1985 and outlines some of the problems that are unique to a large company responsible for a national telecommunications network. Describes the key objectives of the Company and how these are being implemented using the ‘bottom up’ and ‘total quality management’ approaches. Discusses the training of management in the ‘total quality’ concept and introduces the ‘customer’ as the focus for every single employee in the Company.
Measurement of Impact Loads using a Laser Doppler Velocimeter
Authors: Birch R S , Jones N
Published: February 2007

The design and selection of transducers is an important consideration for the measurement of impact loads. This paper examines a load-measuring transducer based on a non-contact laser Doppler principle. An experimental study assesses the deformations and velocities obtained using a laser Doppler velocimeter and compares the mean and peak loads with those recorded by an accelerometer and a load cell. The paper concludes that this device is a valuable tool in the structural impact research field.
The Effect of Joints on the Transverse Vibration of a Simple Structure
Authors: Dunne F P E , Heppenstall M
Published: February 2007

Transverse vibration tests were carried out on a cold-drawn mild steel tubular beam containing annular metal-to-metal joints. The tests were also carried out on an unjointed beam of the same dimensions. An axial compressive preload was applied giving a compressive stress in the range of 0–80 N/mm2. Joints between rough turned surfaces, between ground surfaces and mixed joints between both types of surface were used.

Dynamic bending stiffnesses of the joints over the range of compressive stress were determined. Stiffness of the turned and mixed joints was found to be proportional to preload. Stiffness of ground joints increased with preload, but not proportionally.

Theoretical models were developed to determine joint bending siffness and natural frequencies of transverse vibration of the jointed beams. Predicted values of joint bending stiffness for ground and turned joints were in reasonable agreement with the experimental results.
Use of Profilometric Measurements in Cavitation Erosion and Corrosion Studies
Authors: Wood R J K
Published: February 2007

In this note profilometry has been used to determine the magnitude of the synergistic effect of cavitation erosion and corrosion. The maximum depth of penetration for erosion, corrosion and erosion-corrosion have been used.
The Effect of Fluid Inertia and Cavitation on the Performance of Oscillatory Squeeze-Film Bearings
Authors: Hashemi S M R , Roylance B J
Published: February 2007

The underlying objective of this investigation is to provide a simple model and solution for predicting the behaviour of cavitation and its effects. The analytical cavitation model developed is based on experimental observations and is confined to an incompressible, Newtonian lubricant subjected to a squeezing sinusoidal motion between two parallel, flat circular plates under laminar flow conditions. The combined effects of fluid inertia and cavitation are considered for conditions of viscous and inertia solutions, Re0 = 0 and Re0 ≥ 1 respectively. Both dynamic and steady state behaviour of the growth and collapse of a centrally located single bubble are analysed in which the effects of fluid inertia are examined. The results of analysis are presented in terms of excursion ratio e, Sommerfeld number S, squeeze velocity number N and the normalized bubble parameter α30. The results confirm the formation of a net force due to fluid inertia and cavitation under different flow conditions.
A New Approach to the Solution of Elastohydrodynamic Lubrication of Crankshaft Bearings
Authors: Xu H , Smith E H
Published: February 2007

A study of the elastohydrodynamic lubrication of crankshaft bearings in internal combustion engines is presented in this paper. A new method for simulating the performance of a finite width bearing and two-dimensional flexible structure is developed and introduced. The method is based on a finite element model of the structure and finite difference approximation of the Reynolds equation. In order to reduce the number of unknowns in the derived simultaneous equations, a modified form of the Reynolds equation is employed. The non-linear system of integro-differential equations is solved by a Newton—Raphson method. Analysis of a dynamically loaded Ruston—Hornsby bearing is performed and the method is found to be both rapid and robust. The influence of mesh and time step sizes upon the solution accuracy is studied.
High-Temperature Lubrication
Authors: Lansdown A R
Published: February 2007

The maximum temperature at which a mechanical system can operate is often determined by the need for lubrication. The paper considers the various heat sources, ambient temperature, mechanical or chemical inputs, and flash temperatures, and discusses their influence on different types of lubrication.

The actual temperature limitations are imposed by physical or chemical changes in the lubricant itself, or by changes in a specific lubrication mechanism such as adsorption. The nature of these types of change is described, together with the dominant importance of residence time on the extent of deterioration.

Some actual temperature limits for particular lubricants are listed, and the paper suggests some possible design techniques for extending the upper temperature limits for lubrication.
Envelope Theory Applied to Globoidal Cam Surface Geometry
Authors: Backhouse C J , Jones J Rees
Published: February 2007

This paper describes a technique based on envelope theory for deriving geometric properties of a globoidal type cam. The cam surface is taken to be the spatial envelope formed by a cylindrical cutting tool as it moves relative to the cam. The method employs a variation on classical envelope theory in that the three-dimensional problem of defining the cam surface is reduced to a set of two-dimensional ones. Results are presented to show that the cam surface form can be defined including values of pressure angles and cam surface curvatures for an illustrative case.
The Tribology of Automotive Components: Development of Verified Predictive Design Techniques
Authors: Parker D A
Published: February 2007

The paper describes the iterative development of verified predictive techniques, with examples taken from a wide range of lubricated and non-lubricated automotive components. The techniques can be used to propose a model which can be applied in real design situations where integration into an overall product engineering design strategy is required.
Invariant Properties of Automotive Suspensions
Authors: Hedrick J K , Butsuen T
Published: February 2007

Dynamic systems which are composed of interconnected sub-systems are subject to dynamic ‘constraint equations’ which are independent of the nature of the interconnections. A dynamic constraint equation is developed for a quarter car model of an automotive suspension. It is shown that only one of the three transfer functions (acceleration, suspension deflection and tyre deflection) can be independently specified and that the first two contain ‘invariant points’ at frequencies within the frequency range of interest. These constraint equations lead to conclusions with respect to trade-offs between the three transfer functions. Improvements in all three can be obtained near the unsprung natural frequency; however, severe trade-offs are shown to exist at all other frequencies.
A Model of Vehicle Rollover Due to Side Impact Collision
Authors: Wood D P
Published: February 2007

Cars involved in side impact collisons have been known to roll over as a direct consequence of the side impact. A simple mathematical model is derived for collision rollover in central and eccentric side impacts. It is shown that the minimum impact velocity of the bullet vehicle or object necessary to cause rollover is dependent on the mass ratio of the struck vehicle to that of the bullet vehicle/object, the impact height, the tyre-road friction and on the eccentricity of the impact. The rollover velocity decreases as friction is increased. Consequently this form of rollover will, in general, most often occur on dry roads and at moderate to high impact velocities. The model is compared with data from staged motorcycle/car impacts and with two road accidents which resulted in rollover.
A Three-Dimensional Finite Element Approach to Drum Brake Analysis
Authors: Watson C , Newcomb T P
Published: February 2007

This paper outlines the extension of the ‘GAPFRIC’ concept to model in three dimensions the frictional interface between brake linings and drum. Analyses have been completed to investigate the combined axial and circumferential expansions on the local surface temperatures, interfacial pressure distributions and consequent brake performance. Predicted results of the simulation applied to a S cam-operated brake indicate that in the circumferential direction higher pressures are attained at the ends of the linings of the leading shoe than in its central region. Higher pressures are also reached at the cam end of the trailing shoe. Axial pressure variations also exist across both shoes. The coupling of pressure and temperature variations together with the effects on frictional changes over the lining surface produce changes that result in the frictional drag per unit area tending to be reasonably constant over the interface between drum and lining. These results have been validated by comparison of the calculated brake performance with that measured on a brake mounted on a dynamometer.
Operational Experiences with LNG Storage Tanks
Authors: Banfield G R , Fairbairn G W
Published: February 2007

British Gas has 20 above-ground LNG tanks in service, representing some 250 tank-years of experience. No major incidents have occurred with any of these tanks. Operational problems have been experienced with tanks, bunds, LNG valves and pumps; these have all been overcome without recourse to warming up or decommissioning the tanks. This paper summarizes British Gas's operational experiences, describing, in particular, how problems have been overcome.

One above-ground tank has been decommissioned recently, for operational rather than technical reasons. This provided an excellent opportunity for detailed study of the condition of an LNG tank after 14 years of operational service. In addition mention is made of the (now decommissioned) in-ground LNG storage tanks, formerly used by British Gas.
A Method of Calculation of the Torque-Speed Characteristics of a Dynamic Separator
Authors: Balakrishnan M , Srinivasan P S
Published: February 2007

A method of computing the torque and power requirements of a dynamic separator for different speeds of operation is proposed. The method makes use of the experimentally determined drag coefficients for the existing types of blade geometry of the impeller and the principles of energy and momentum for the calculation of torque at different speeds. The interference effect between blades is taken into account using an empirical formula. Comparison of the computed values of power with the actual power measurements shows that there is good agreement between them.
Transients During a Railway Air Brake Release Demand
Authors: Murtaza M A , Garg S B L
Published: February 2007

This paper deals with the simulation of railway air brake release demand of a twin-pipe graduated release railway air brake system based on the solution of partial differential equations governing one-dimensional flow by the finite difference method supported by extrapolation/interpolation. Air brake release demand is simulated as an exponential input of pressure. The analysis incorporates the corrections needed to be used for various restrictions in the brake pipeline. Results are in good agreement with the laboratory data.
Rolling Stock Projects
Authors: Band C E
Published: February 2007

A seminar on ‘Rolling stock projects’ was organized by the Railway Division of the Institution of Mechanical Engineers in London on 21 April 1989 as a logical follow-on from a previous seminar held in 1988 covering the subject of locomotive and rolling stock procurement
Development and Implementation of a Modern Modular Locomotive Brake System
Authors: Leigh M J
Published: February 2007

The paper covers the development and implementation of a modern modular brake system suitable for heavy haul locomotives. The background to the system is outlined together with the thinking behind the design. The paper describes the development and some of the testing that the system underwent for operational and compatibility requirements plus the development of the packages for fitting within the locomotive and installation on to a brake equipment frame. The introduction of the equipment into service with different railway authorities is discussed together with its interaction with radio-controlled working. The paper concludes by discussing the success of the concept plus the results of testing on the size of brake pipe exhaust and the effect on air flow of brake pipe diameter. Recommendations are made to reconsider the method of control and to consider the improvements of the introduction of a second feed pipe.
Some Aspects of Gear Tribology
Authors: Snidle R W , Evans H P , Dyson A
Published: February 2007

This paper reviews work being carried out at Cardiff on tribological aspects of heavily loaded gear tooth contacts. The contacts occurring in high conformity (Wildhaber-Novikov) gears have been analysed to predict the thickness of the lubricant film, and the work has been extended to include a consideration of surface roughness effects in gears of this type.

For conventional gears a different rough surface elastohydrodynamic (EHL) analysis has been developed and this shows that roughness features can become almost flattened where they occur within the main EHL contact. Recent work on scuffing research is described and new developments in the search for a physical explanation of this form of failure are discussed.
HOTOL Space Transport for the Twenty-First Century
Authors: Burns B R A
Published: February 2007

The main structural, aerodynamic and systems engineering features of HOTOL and their evolution during the design study are described. Operational procedures are also outlined.
Testing of Total Hip Replacements: Endurance Tests and Stress Measurements: Part 1: Endurance Tests
Authors: Humphreys P K , Orr J F , Bahrani A S
Published: February 2007

This is a paper in two parts. Part 1 gives details of fatique tests carried out on Howse II hip prostheses. Three types of tests were carried out in accordance with three different draft test standards. Standard (I) was BSI DD91: 1984 in which the load range is 0.3–4.1 kN and the antero-posterior offset angle is 15°. Standard (II) was BSI DD91: 1986 where the load range is 0.3–2.3 kN and the offset angle is 9°. Standard (III) was ISO/DP 7206/3 in which the load range is 0.3–4.1 kN and the offset angle is 0°. Four specimens were tested according to each standard. It was found that all the specimens tested according to standard (I) failed by fatigue after less than 6 times 105 cycles. All the specimens tested according to standards (II) and (III) withstood 5 times 106 cycles without failure. It is clear that the offset angle has an important influence on the fatigue life of the prosthesis. It is concluded that tests according to standard (I) are too severe, while tests according to standards (II) and (III) are either adequate or lax. This led to Part 2 of the investigation where the stresses in the prostheses were measured and calculated.
Analysis, Design and Development of a Carbon Fibre Reinforced Plastic Knee-Ankle-Foot Orthosis Prototype for Myopathic Patients
Authors: Granata C , De Lollis A , Campo G , Piancastelli L , Merlini L
Published: February 2007

A traditional knee-ankle-foot orthosis (KAFO) for myopathic patients has been studied for the assessment of loads and fatigue resistance. Starting from this basis a thermoplastic matrix carbon fibre reinforced plastic composite (CFRP) KAFO has been developed in order to reduce the weight. A finite-element simulation programme for deformation analysis was used to compare the behaviour of conventional and CFRP orthosis. There were no breakages either of the prototype or of its parts. The CFRP orthosis allows a weight reduction of more than 40 per cent.
Femoral Strain Adaptation after Total Hip Replacement: A Comparison of Cemented and Porous Ingrowth Components in Canines
Authors: Vanderby R , Manley P A , Belloli D M , Kohles S S , Thielke R J , McBeath A A
Published: February 2007

The purpose of this study was to investigate if experimental strain analysis is predictive of femoral adaptation after total hip replace- ment (THR). Ten large adult dogs underwent unilateral THR with identical implants. Five implants were press fit for porous ingrowth fixation, andjive were cemented. Four months after surgery femora were harvested. Strain gauge rosettes were applied to the femora at eight proximal locations. Femora were compressively loaded on the head of the femur or femoral component. Strain data represented three conditions: preoperative, acutely postoperative, and four-month postoperative. The unoperated, femur of each dog was used to simulate preoperative and acutely postoperative behavior of the contralateral implanted femur. Strains from each condition were com- pared. Transverse femoral sections were obtained through the levels of the strain gauges. Fine detailed radiographs were used to quantify morphological changes. Results showed cemented and uncemented implantations produce yimilar trends but different amounts of bone adaptation. Adaptations were generally consistent in direction with strain perturbations caused by implantation, hut the extent of adaptation did not strongly correlate with the magnitude of perturbations. Also, there was no consistent trend towards normalization of altered strains. Results suggest that strain perturbations after THR may be mechanical triggers for morphological changes, but caution is required when predicting the extent of these changes or the autoregulatory role of strain.
Determination of Contact Area in ‘cushion Form’ Bearings for Artificial Hip Joints
Authors: O'Carroll S , Jin Z M , Dowson D , Fisher J , Jobbins B
Published: February 2007

Current forms of artificial hip joints produce wear debris, which contributes to loosening of the prostheses. These ‘hard’ joints articulate with boundary or mixed lubrication, whereas the natural joint articulates with full fluid film lubrication. An artificial joint that articulates with full fluid film lubrication could greatly reduce wear and frictional torque and hence reduce the incidence of loosening and inflammatory tissue reaction. The use of a thin lining of low elastic modulus in the acetabular cup is one possible way of promoting full fluid film lubrication. In the design of such cushion forms of bearings, it is important to be able to predict the contact area, stress distribution and film thickness. This paper presents experimental techniques to determine the contact area in low elastic modulus layers and compares these measured areas with theoretical predictions using linear elasticity theory. At low loads experimental results and theoretical predictions were close. However, at loads above 300 N, the theory overestimated the width of the contact area by up to 8.5 per cent. This difference is mainly attributed to the non-linear behaviour of the elastomer at the higher levels of stress.
A Finger Function Simulator and the Laboratory Testing of Joint Replacements
Authors: Stokoe S M , Unsworth A , Viva C , Haslock I
Published: February 2007

The design of a metacarpophalangeal (MCP) joint function simulator was undertaken and resulted in a versatile machine which offers the facility to apply both dynamic and static loading to a joint, following closely the physiological levels and patterns imposed in vivo. An additional feature was the opportunity to investigate the effect of varying the degree of joint instability.

Long-term tests performed on Swanson silastic implants have produced failures of the kind seen clinically, which is very encouraging since it would seem to validate the claim that the simulator successfully imitates the finger function.
Hydroviscous Drive and Some New Developments
Authors: Wu X M , Wei C G , Sproston J L
Published: February 2007

The hydroviscous drive (HVD) is a kind of variable speed coupling in which power is transmitted from the driving part to the driven part through the viscous shear of the interposed oil film. The HVD has been employed in industrial applications for more than twenty years, especially in the speed regulation of fans, pumps and blowers, and also for the controlled acceleration of high inertia loads. Its advantages include the selection of a continuously variable speed and a fast response together with isolation as well as direct drive. Further applications are foreseen, such as in brakes and dynamometers. This paper presents a systematic theoretical and experimental analysis of the HVD. More significantly, some new ideas and developments, for instance the hydroviscous mechanical drive, which uses a combination of the HVD and planetary gear train, will be discussed.
Turbomachinery Vibration Case Histories—Design Problems of Rotating Machinery in Operation
Authors: Mirro J
Published: February 2007

The machinery case histories detailed in the present paper illustrate some of the variety and subtlety of design problems encountered in existing rotating machinery and their engineering resolutions, including upgrade and redesign. A significant purpose of the technical information presented here is to help in avoiding improper diagnosis and treatment of machinery design problems by treating them as recurring maintenance problems. This common misdiagnosis continues to result in unnecessary maintenance expense and very costly downtime.
A Strategy for Selecting Engineering Components
Authors: Vogwell J , Culley S J
Published: February 2007

Selecting components from catalogues is an important engineering activity and it is found that computerizing the process provides major advantages for the design engineer and has serious implications for manufacturers.

Difficulties arise when computing the selection procedure, however, because catalogue data formats and analysis techniques (which are essential for verifying suitability in an application) have evolved from manual usage. Computer data handling methods and search strategies differ significantly, consequently, major changes are necessary to transfer information from catalogue formats in order to achieve a fully computer aided system approach.

Experience has been gained at Bath University designing and developing numerous component selection programs; dealing with bearings, springs, gears, fastenings etc. One system has been developed to a commercial standard.

This paper describes why there is increasing interest in automating the selection of catalogue components. It discusses the nature of the data and some of the salient features which are considered desirable if such programs are to be fully exploited by practising engineers. In particular, the strategy which has been used for efficiently dealing with the different data types inherent with mechanical components is shown.
A Study on Prediction of Welding Current in Gas Metal arc Welding Part 1: Modelling of Welding Current in Response to Change of Tip-to-Workpiece Distance
Authors: Kim J W , Na S J
Published: February 2007

A model of the welding arc in gas metal arc welding (GMAW) is very useful for the analysis and automation of the welding process. Thus a mathematical model that is able to predict the welding current change in response to the variation of tip-to-workpiece distance was proposed for the gas metal arc welding process. The model was deveoped by analysing the welding arc behaviour and by considering the characteristic of the welding power source.

The welding current variation was calculated with respect to various welding conditions and slope of the power source characteristic. By comparing the calculated and measured current signals, it could be concluded that the model proposed can well define the relation ship between welding current and tip-to-workpiece distance for various welding conditions in gas metal arc welding. Both the calculated and measured signals of welding current show almost a linear variation in response to the linear change of tip-to-workpiece distance
An example of Automatic Two-Dimensional Component Inspection Using Computer Vision
Authors: Al-Kindi G A , Baul R M , Gill K F
Published: February 2007

Automatic inspection processes require intelligent devices which combine the attributes of existing measuring techniques with those of the experienced practitioner. With the rapid growth of solid state electronics and computer applications during the last two decades, the field of computer vision has developed significantly and its application in the field of inspection is becoming a reality. This paper examines the use of computer vision for the inspection of engineering components. A range of existing edge detection algorithms has been tested for their suitabiliy for two-dimensional component inspection together with a new algorithm for application when contour tracing methods fail to detect localized edges in a complex scene.

Assessments are mainly subjective but are also based on computational speed; an important factor in on-line inspection applications. An algorithm has been proposed which can be used for the simultaneous analysis of internal and external contours with the ultimate aim of automatic component classification. In addition an alternative boundary coding system eliminates errors which are normally associated with other coding methods when monitoring components at different orientations.
A Thermal Model for Cyclic Glass Pressing Processes Using Transmission Line Modelling
Authors: Pulko S H , Phizacklea C P
Published: February 2007

This paper describes a numerical model for predicting temperature fields both in the glass and the mould tools during cyclic glass pressing processes. The model uses the TLM (transmission line modelling) technique and relevant aspects of the technique are described. The model is used to predict the effect of changing various parameters on the steady state temperatures developed.
Estimation of the Coupling Loss Factor of Structural Joints
Authors: Clarkson B L
Published: February 2007

This paper shows how Bishop's receptance method can be used to derive the transmission of vibrational energy across a structural joint. The results are averaged over frequency bands and on the assumption of light damping an approximate formula for the coupling loss factor is obtained. This is an important parameter in the statistical energy analysis method of estimating the response of structures to broad-band random forces. The results compare well with those obtained by the travelling wave method.
An Inverse Method for the Design of Bodies of Revolution by Boundary Integral Modelling
Authors: Lewis R I
Published: February 2007

A surface vorticity boundary integral method is presented for the design of bodies of revolution in axisymmetric flow. The analysis finds the desired body shape to deliver a prescribed surface potential flow velocity or pressure distribution. To achieve this the body surface is simulated by a flexible vorticity sheet of prescribed strength. Starting from an arbitrary first guess for the body shape, normally an ellipsoid, the flexible vortex sheet is successively realigned with its own self-induced flow field during an iterative process which converges accurately onto the desired shape. A well-proven analysis method is also presented for back-checking the final design.
Computer Simulation of a Variable Fill Hydraulic Dynamometer; Part 1: Torque Absorption Theory and the Influence of Working Compartment Geometry on Performance
Authors: Raine J K , Hodgson P G
Published: February 2007

A mathematical model of the steady state torque absorption process in variable fill hydraulic dynamometers is described. This is the initial part of a general model that has been developed to simulate the dynamic behaviour of Froude-type dynamometers under open-loop control and of an engine/dynamometer system under various closed-loop control modes.

In this paper, the equations for steady state torque, energy dissipation, fluid vortex pressure in the working compartment and water outflow from the dynamometer are presented. Predictions by the model for the special case of characteristic running full torque absorption performance are compared with experimental test bed results for different working compartment geometries. Effects of vane angle and working fluid properties on maximum torque capability are examined. Subsequent parts of this paper will address the dynamic variable fill simulation.
Calculations of a Curved-Pipe Flow Using Reynolds Stress Closure
Authors: Lai Y G , So R M C , Anwer M , Hwang B C
Published: February 2007

It has been observed that as a fully developed turbulent flow enters a curved bend the anisotropy of the normal stresses near the outer bend (furthest from the centre of the bend curvature) increases. According to the arguments of vorticity generation, a sudden increase in the anisotropy of the normal stresses may lead to the formation of a secondary flow of the second kind. If this secondary motion is to be calculated, then a near-wall Reynolds stress closure that can mimic the anisotropic turbulence behaviour near a wall has to be used.

This study presents the results of just such an attempt. In addition, two high Reynolds number closures assuming wall functions in the near-wall region are tested for their ability to replicate the behaviour of the normal stresses in a curved-pipe flow. These two closures differ in their modelling of the pressure-strain terms. Consequently, the effects of near-wall and pressure-strain modelling on curved-pipe flow calculations can be examined. Comparisons are also made with recent curved-pipe flow measurements. The results show that pressure-strain modelling alone is not sufficient to predict the rapid rise of the anisotropy of the normal stresses near the outer bend, and hence the formation of the secondary flow of the second kind. Overall, the near-wall Reynolds stress closure gives a more accurate prediction of the measured mean flow and turbulence statistics, and a realistic calculation of the secondary flow of the second kind near the outer bend.
Conditions for Translation and Rotation of Bodies on Frictional Surfaces
Authors: Nowell D , Hills D A , Munisamy R L
Published: February 2007

This paper is concerned with the quasi-static motion of a body resting on a frictional surface when subjected to an arbitrary imposed displacement by a small frictionless finger. A simplified object with three distinct feet is used as an illustration but the method adopted can be generalized to bodies with more feet or distributed contact. A closed-form expression is found which enables the determination of the conditions necessary for a body to rotate about a point of support and a more general numerical technique for determining the instantaneous centre is presented. The indeterminacy that occurs when the points of support lie in a straight line is also discussed.
Piston-Liner Thermal Resistance Model for Diesel Engine Simulation: Part 1: Formulation and Tuning
Authors: Rasihhan Y , Wallace F J
Published: February 2007

A simple, effective and computationally economical piston-liner thermal resistance model for diesel engine simulation is described. In the model, the detailed shape of the piston and its axial movement and interaction with liner nodes are all taken into account. An imaginary node within the piston provides the necessary temperature difference between the piston and the liner nodes for conductive heat transfer, which is expected to reverse its direction with liner insulation. In the liner, an axially symmetric two-dimensional heat-transfer model is used. Later the piston-liner model is tuned for the experimental single cylinder, direct injection, Petter PH 1W engine used at Bath University, against the experimental piston temperature and liner temperature distribution.
Friction, Surface Science and Tribology—A Personal View
Authors: Tabor D
Published: February 2007

This paper is a rather personalized account of research carried out over many years by a physicist exploring the basic mechanisms of friction and the general field of tribology. It indicates how side-tracks have often led to other rich pastures and reflects the sometimes fruitful unpredictability of scientific research. This paper records several such felicitous surprises emerging from studies of friction. These include the direct measurement of surface forces, the adhesion of elastomers in terms of surface energy and viscoelastic properties, the skid-resistant properties of tyres, diffusion in polymers and measurement at the molecular level of the shear properties of oriented layers of boundary lubricants.

In all this work the author is conscious of the original initiatives of the late Professor Bowden and recognizes the major contributions made by research students and colleagues. He is also conscious of many elements of serendipity.
Elastohydrodynamic Studies of Three-Lobe Journal Bearings with Non-Newtonian Lubricants
Authors: Goyal K C , Sinhasan R
Published: February 2007

A computer aided elastohydrodynamic study of the three-lobe journal bearing with non-Newtonian lubricants is presented for the static and dynamic performance characteristics. The three-dimensional momentum and continuity equations in cylindrical coordinates governing the flow of Newtonian lubricants in the clearance space of a three-lobe journal bearing have been solved using the finite element method. The non-Newtonian effect is introduced by modifying the viscosity term for the model iteratively. Three-dimensional elasticity equations are solved to obtain deformations in the bearing shell. Static and dynamic performance characteristics are presented for a wide range of values of non-dimensional load, deformation coefficient and non-linearity factor.
The Effects of Mixture Preparation and Trapped Residuals on the Performance of a Spark-Ignition Engine with Air-Shrouded Port Injectors, at Low Load and Low Speed
Authors: Brown C N , Ladommatos N
Published: February 2007

This paper is concerned with the steady state combustion performance of a port-injected spark-ignition engine operating at low load and low speed. The main areas of investigation were the effects of mixture quality and trapped combustion residuals on combustion performance. The behaviour of the inlet manifold fuel film was also investigated under various engine running conditions.

The effects of injection timing were quantified, both with warm and hot engine coolant. Each of the six fuel injectors on the engine was equipped with an air-shrouded injector which improved fuel-spray atomization. Tests were carried out both with and without air flowing through the shrouds. A new method is also presented which provides a measure of the size of the inlet-manifold wall film under various engine running conditions. Finally, measurements of the amount of trapped combustion residuals are presented, and their effect on combustion performance is quantified.
The Two-Stroke Cycle Engine, Proscribe or Prosper?
Authors: Blair G P
Published: February 2007

This Address is concerned with the work carried out by an engineering academic at The Queen's University of Belfast over the last 26 years. It describes the motivation which impelled the author towards a career in mechanical engineering and into a specialist field from which he has never strayed. It describes research and development into the design of the two-stroke cycle engine, which today is identified as a potential candidate for automobile powerplant production within the decade. At the same time the Address illustrates that much of this research and development, including the design, manufacture, build, test, and development of prototype automotive engines, has been heavily contributed to by both undergraduate and postgraduate students as part of their education and training at the university. It is contended that this approach is a vital component of a relevant university education and training for student and academic alike.
Practical Tools for Vehicle Impact Simulation Part 2: An Integrated Approach Using Oasys Dyna3D
Authors: Miles J C , Sturt R M V , Leach J H
Published: February 2007

This paper describes the use of a non-linear finite element analysis program (OASYS DYNA3D) for the simulation of vehicle impact events. The purpose of the paper is to demonstrate how one single program can be used at a number of different levels of complexity to serve the needs of the analyst at all stages of vehicle design. Examples are given of lumped mass/spring simulations, continuum (shell/brick) simulations and an intermediate stage in which the two analytical philosophies are combined to form a ‘hybrid’ approach.

The paper conclues with some observations on the future for hybrid modelling techniques and suggests some simple extensions which would allow the occupant and safety restraint systems to be included in the global vehicle simulation.