bluuebunny/crossref_metadata_2025 huggingface dataset:
Ride Improvements to a Class 31 Locomotive
Authors: Ronaldson A D
Published: February 2007

This paper reviews the approach adopted in overcoming rough riding on the Class 31 locomotives. It describes how the problem was defined, contains an explanation of the technical investigation, and resultant design modifications, on-track testing, and finally analysis of results, thus demonstrating achievement of a successful design solution.

The paper describes how excessive hysteresis in the existing spring tended to degrade ride performance. The improvements in the ride have been achieved by reducing this friction level significantly, which has resulted in a corresponding reduction in amplitude of the body bending oscillations. This was achieved by replacing the existing bolster laminated spring with a ‘taperleaf’ spring.
Driver's Environment Technology in the Driving Cab
Authors: Greaves T A
Published: February 2007

This paper gives an appreciation of the need to bring available technology to the aid of the driver in the interest of safety, and an appraisal of what is on offer together with future developments.
Interaction with the Customer During Manufacture
Authors: Giese K-D
Published: February 2007

This paper covers co-operation between manufacturer and customer during the various stages of design and development, manufacture and quality assurance in addition to acceptance and commissioning.
Wealth from Technology
Authors: Neale M J
Published: February 2007

The President concentrates on the creation of real wealth from technology by the activities of professional engineers. Real wealth creation, in which useful facilities are created for mankind, is shown to be a process which is both very challenging for the individuals involved, and very socially desirable for the group or country of which they are a part. It needs to be distinguished from the making of money by the typical City deal, which is an essentially selfish process.

The Address looks at the mechanisms by which new products and processes are created to generate real wealth and it also comments on the ways in which professional engineers can remain involved in this exciting process, without the need to move into purely management roles in order to advance their position in society.

The wealth creation mechanism is shown to be based on combinations of knowledge and experience which the Address examines in more detail. This includes the potential for particular techniques for organizing the transfer of knowledge from research to industry and describes some new methods for correlating and understanding operating experience.

The need for a high level professional engineering involvement is seen to be critically important. Where companies do not involve their own engineers on this work as a technological activity at board level, there is considerable scope for professional engineers to provide the services required as independent consultants.

The whole area of real wealth creation is an activity that is ripe for a much increased involvement of professional engineers and the Institution.
Innovation and the Role of Engineering Design in Profitable Organic Business Growth
Authors: Coplin J F
Published: February 2007

Innovation and the timely use of advanced technology are decisive factors in competitive edge and profitability. However, these are the factors which give rise to the concern of management and the investor. Experience has taught us to be sure that our product and its process of manufacturing contain innovation, but that it must be sparingly used and focused on achieving the improved competitive edge and profitability. The innovative step must be developed with the last word in thoroughness. It must be explained with great care and in a manner which is readily understood by management and the investor ahead of time in order to obtain the release to proceed. The achievement of interim milestones en route to the effective exploitation of the innovation will retain confidence as time and money is spent ahead of the full realization.

The engineering design team plays the key professional role in focusing the issues.

The studies done in a small company, Rolls-Royce Business Ventures Limited, a wholly owned subsidiary of Rolls-Royce plc, have focused the importance of new businesses which can be described as discontinuities. For these special techniques are required to achieve satisfactory launch and profitable growth thereafter. Within the Rolls-Royce history there are important examples of how it was done. These can be analysed to distil out what factors were important.
Marine Gearing—Development and Technology
Authors: Sigg H
Published: February 2007

The first part of this paper deals with the development of the surface-hardened and ground marine gear. The accuracy which can be attained today in finish machining of such gears is discussed. Modern gear grinders can now produce two- and three-dimensional tooth corrections of any shape deemed necessary.

The second part describes the more sophisticated combined marine propulsion gear system CODAG and a reverse gear for high-power transmission. Rules for the safe operation of such systems are laid down and the required synchronizing clutches are described.
Low-Temperature Convectors for Space Heating
Authors: Angeiino G
Published: February 2007

Two convectors for space heating, designed for low-temperature operation, were built and tested. Both convectors consisted of an extended surface heating element placed at the bottom of an enclosure acting as a chimney. The first one was intended for an almost isothermal operation while the second one allowed an important cooling of the heating medium. A computer program was employed to optimize the heaters' geometry. Fin efficiency was found not to be accurately predicted by ordinary relationships in the case of unusual fin geometries: a finite difference analysis was employed as a more satisfactory computation tool. Tests were performed in a thermostatic test chamber and gave results in good agreement with the theoretical predictions. Owing to the influence of air temperature around the heater on chimney draft, ambient air temperature distribution is to be taken into account in the theoretical model in order to obtain accurate results. Both heaters tested gave a considerably better output than ordinary heaters of similar dimensions and working at the same temperature. In order to increase the heat delivery, one of the heaters was modified to accommodate a small fan. Even for extremely low electric power input, assuring a totally noise-free operation, a sizeable improvement of thermal power output was observed.
The ‘Secondary Source’ Method for the Measurement of Pump Pressure Ripple Characteristics Part 2: Experimental Results
Authors: Edge K A , Edge K A
Published: February 2007

Tests, using the ‘secondary source’ method, have been performed to measure the fluid-borne noise characteristics of several hydraulic pumps. This method has proved to give very repeatable measurements of source flow ripple and source impedance, and the results show good qualitative agreement with theoretical models. Results are verified by using them to predict the pressure ripple in a typical hydraulic circuit and comparing this with measured pressure ripple. Correlation is shown to be good.
Computer-Aided Numerical Analysis and Design for Cold Extrusion of a Spur Gear
Authors: Yang D Y , Yoon J H , Lee C M
Published: February 2007

The die profile for extrusion of a spur gear section through a continuously curved die is described by a parametric form in the cylindrical coordinate system using a blending function and Fourier series expansion. A finite element analysis is made for steady state three-dimensional extrusion of a spur gear section. The distribution of stress and strain components is determined. In treating the incompressibility, the penalty constraint method based on the rigid-plastic material model is used. The initial estimate for the initial velocity field is obtained from the assumption of linear viscous material. The work hardening effect is considered by integrating the effective strain rate along each streamline through interpolation by the least-square method. The elastic deformation of the die has been computed by the elastic finite element analysis. It is shown that the computer aided analysis and design of the extrusion process could help to achieve more precise production of gears with improved productivity.
District Heating and/or District Cooling Distribution Pipelines: Optimal Configurations
Authors: Babus'Haq R F , Probert S D , George H E
Published: February 2007

Factors influencing the steady state heat transfers from a horizontal hot-water (or to a chilled-water) pipeline within a relatively cold (or hot) horizontal rectangular trench filled with either (a) atmospheric pressure air or (b) hollow plastic spheres or Lytag in order to simulate a buried district heating (or cooling) distribution network have been considered. A series of experimental measurements as well as finite element and finite difference predictive analyses revealed the optimal configuration, for each set of considered circumstances, is that which achieves the minimum steady state rate of heat exchange between the supply pipes and their surroundings under the considered conditions. The recommended configuration for both the district heating and cooling systems is to place the two pipelines one above the other in the trench, the hotter pipe being the upper member. This differs radically from the arrangement of the pipelines traditionally adopted in district heating or district cooling designs (the pipes being placed side by side), and its adoption leads to at least a 4 per cent improvement in energy thrift. Such a saving can be achieved with no extra constructional costs, and the savings should be significant over the lifetime of either the district heating or cooling system.
The Verification of Centrifugal Pump Performance Guarantees by Acceptance Tests—A Statistical Method
Authors: Grist E , Hentschke R P
Published: February 2007

A statistical method of verifying that centrifugal pump performance requirements have been met is presented which has advantages over the BS 5316 (ISO 3555) method currently in use. The method can be used to calculate from test data both the lower and the upper confidence limits of pump total head at a given rate of flow and compare them with guaranteed values, it can also be used to determine the upper limit of pump power input at a given rate of flow. The method is being considered by the International Standards Organisation for inclusion as an option in the forthcoming revision of ISO/BSI standards on pump acceptance tests.

The statistical method is most easily applied using an interactive computer program. A BASIC language program, suitable for use on low-cost personal computers, is presented in the paper.
Implications of Measurement Uncertainty When Using the Thermodynamic Method of Pump Efficiency Monitoring in Water
Authors: Milne A J
Published: February 2007

The thermodynamic method of pump testing is examined using the standard equation as a starting point, and realistic uncertainties are apportioned to each term in the equation to indicate the absolute degree of uncertainty required in differential temperature measurement for compatibility with current test codes. This illustrates the value of uncertainty associated with derived flowrate and the improvements in measurements required so that the uncertainty in both efficiency and flowrate fall within prescribed limits.
The Calculation of Flow in Regenerative Turbomachines by a Streamline Curvature Method
Authors: Andrew D N
Published: February 2007

The streamline curvature method of calculating the axisymmetric flow through conventional turbomachines is adapted to calculate the non-axisymmetric flow in a thin meridional sector of a regenerative turbomachine. The method provides an important tool for investigating the effects of spanwise variations on machine performance. The incorporation of a mixing model and a model for the friction on the passage walls, in addition to the use of a loss model through the blade row, allows an estimation of the relative importance of these sources of loss for the performance of regenerative machines to be made, and the effect of friction is shown to be significant.
Preliminary Design and Performance Prediction Techniques for Centrifugal Compressors
Authors: Whitfield A
Published: February 2007

A procedure is described to design the overall dimensions of a centrifugal impeller. Initial optimization is carried out by minimizing the inlet and discharge Mach numbers. The procedure is developed for a range of possible pressure ratios and the effect of high pressure ratio on the Mach numbers and resultant impeller geometry is discussed. Empirical impeller flow modelling techniques to predict the performance of the proposed design are then briefly reviewed.
Analysis of Alternative Oil Flow Control Methods for High-Power Hydraulic Servocylinders
Authors: Tuokko R O
Published: February 2007

Both the performance and energy efficiency aspects should be considered in dealing with high-power servodrives. This paper discusses the structure, properties and robustness of alternative oil flow control methods for position-controlled hydraulic servocylinders. A general non-linear model of a mechatronic cylinder drive is given and the following four control concepts are analysed: valve control, pump control, hydrotransformer control and electric motor control. The paper discusses the design aspects that should be considered in connection with these system alternatives in order to satisfy the economic and performance demands of modern drive applications.
Steam Turbine Generators for Sizewell ‘B’ Nuclear Power Station
Authors: Hesketh J A , Muscroft J
Published: February 2007

The thermodynamic cycle of the modern 3000 r/min steam turbine as applied at Sizewell ‘B’ is presented. Review is made of the factors affecting thermal efficiency including the special nature of the wet steam cycle and the use of moisture separation and steam reheating. Consideration is given to the optimization of the machine and cycle parameters, including particular attention to reheating and to the provision of feedheating, in order to achieve a high overall level of performance. A modular design approach has made available a family of machines suitable for the output range 600–1300 MW. The constructional features of the 630 MW Sizewell ‘B’ turbine generators from this range are described in detail. The importance of service experience with wet steam turbines and its influence on the design of modern turbines for pressurized water reactor (PWR) applications is discussed.
An Appraisal of Incineration Standards: When is a Standard Not a Standard?
Authors: Porteous A , Barratt R S
Published: February 2007

The application of standards for the control of incinerator emissions is examined. Studies on incinerator emissions and statutory limits on discharges fail to conform to standard conditions. Inadequate knowledge on incineration processes contributes to the inability to define certain design standards, while the lack of agreement on standard conditions for emissions makes comparisons difficult.
Innovation and Tradition in Steam Turbine Engineering
Authors: Gyarmathy G
Published: February 2007

This paper reviews some of the technical achievements of steam turbine engineering, looks at some of the traditional uses of steam turbines and some new opportunities arising from novel developments and compares different forms of energy sources. Until technologies using the direct conversion of energy into electricity in stationary elements progress further, steam turbine generators will continue to be the main source of electric power.
Performance Prediction and Loss Analysis of Low Specific Speed Submersible Pumps
Authors: Thanapandi P , Prasad R
Published: February 2007

A performance prediction procedure is presented for low specific speed submersible pumps with a review of loss models given in the literature. Most of the loss theories discussed in this paper are one dimensional and improvements are made with good empiricism for the prediction to cover the entire range of operation of the low specific speed pumps. Loss correlations, particularly in the low flow range, are discussed. Prediction of the shape of efficiency-capacity and total head-capacity curves agrees well with the experimental results in almost the full range of operating conditions. The approach adopted in the present analysis, of estimating the losses in the individual components of a pump, provides means for improving the performance and identifying the problem areas in existing designs of the pumps. The investigation also provides a basis for selection of parameters for the optimal design of the pumps in which the maximum efficiency is an important design parameter. The scope for improvement in the prediction procedure with the nature of flow phenomena in the low flow region has been discussed in detail.
Exergy Analysis—A Different Perspective on Energy Part 2: Rational Efficiency and Some Examples of Exergy Analysis
Authors: McGovern J A
Published: February 2007

The concept of exergy having been introduced in the first part of this paper, a universal rational efficiency is now defined and a number of examples of exergy analyses is given.
The Transient Pressure Characteristic of a Positive Displacement Vane Pump
Authors: Watton J , Watkins-Franklin K L
Published: February 2007

The precompression and load pressure characteristics of a fixed displacement vane pump are studied both experimentally and theoretically for the pump in its new condition and for two different working fluids. Conventional mineral oil and a 60 per cent oil-40 per cent water emulsion are both considered for a range of pump load pressures. Flow losses are shown to be non-linear and an appropriate mathematical model is developed to embrace this characteristic with the two-displacement geometry design of the pump. The mathematical model is refined to include vane intermediate pressure effects, leading to slightly better performance prediction, and the comparison with measurements is shown to be promising, particularly for the precompression part of the cycle.
Mechanical Engineering Design with Computer Aided Technology: An Industrial Implementation
Authors: Black I , Cross J D.
Published: February 2007

This paper reports on the application of computer aided technology to the design of mechanical products within a UK-based heavy/ medium, batch-manufacturing company operating in the marine engineering sector. An engineering design methodology is outlined which judiciously exploits particular software techniques associated with the two kinds of technology available in the company concerned. These software techniques range from ‘custom-built’ user-extension programs (developed for specific design applications) for use with a minicomputer-based computer aided design (CAD) system, through to enhanced ‘off-the-shelf ‘ applications packages for use on microcomputer hardware. The authors attempt to demonstrate that effective application of the available technology has essentially involved synergizing that technology with the design engineer's knowledge and abilities throughout the design process, and not relying on locking into the use of computer aided methods as a ‘technological fix’ for design problems.
Manufacturing Excellence and World Leadership in the Auto Teller Market
Authors: Patullo W S , Yuile K D. , Christie A
Published: February 2007

NCR (Manufacturing) Limited develops and produces self-service financial terminals for worldwide markets. During the 1980s the Company improved its market position and has led the industry for several years. A major contribution to this success has been a sustained drive for manufacturing excellence.

This article addresses four key strategies being followed: company-wide quality improvement, supply line management, employee involvement and design for manufacture. Illustrations from a pilot design for manufacture project demonstrate that teamwork, innovation and consideration for manufacturing processes can give significant business benefits.
Automatic Tool Selection for Finish Turning
Authors: Maropoulos P G , Hinduja S
Published: February 2007

This paper describes a procedure to select tools for finish turning operations performed on a CNC (computer numerically controlled) turning centre. The finishing tools considered herein consist of a holder and an indexable tungsten carbide insert. The finishing profiles may be stepped or even contain a recess/shoulder. In the former case, only one tool is selected but in the latter a pair of tools, forming a unit, is selected. In both cases, several alternative solutions are evaluated and presented, in increasing order of normalized machining cost, to the user who then makes the final decision.

Rather than make extensive calculations to determine a precise machining cost, the approximate cost of machining with a tool is based on a nominal length and an average profile diameter, and on cutting parameters which, although approximate, are realistic because the procedure takes into consideration constraints such as chipbreaking, surface finish required and diametral tolerance. Extensive graphic facilities are provided so that the user can visually verify that a tool selected by the system does not collide with the workpiece or the work-holding device.

Three examples are included and the tools selected for them demonstrate the considerable reduction in machining cost that is possible when compared with non-optimal solutions.
Machining of Titanium and its Alloys—a Review
Authors: Machado A R , Wallbank J
Published: February 2007

Even though a new generation of tool materials is now available which is revolutionizing machinability of a large number of work materials, the machining of titanium continues to be a problem. In the present paper an analysis of the main machining problems, chip formation, tool wear and wear mechanisms, are presented. Alternative methods of machining such expensive and difficult-to-machine materials are also indicated; these include the use of rotary and ledge tools along with ultrasonic assistance.
Supersonic Jet Texturing of Yarns
Authors: Wray G R , Acar M
Published: February 2007

Almost all aspects of textile production increasingly feature the application of fluid jets and this paper reviews some of these in connection with the specific field of synthetic filament processing, for example the mingling or interlacing of false-twist textured yarns and the hot fluid texturing process for carpet pile yarns. Particular attention is then given to the texturing of filaments by cold air jets operating at supersonic speeds in view of the two authors' considerable advancements of knowledge in this growirtgly significant field of application for the man-made fibres.
On the Quasi-Static Design of Machine Tool Spindles
Authors: Al-Shareef K J H , Brandon J A
Published: February 2007

The paper simplifies the analysis of the general multi-stepped spindle-bearing system model. Various design parameters are considered with the objective of attaining high static stiffness in the cutting zone. Parameters considered in the study include bearing spacing and stiffness, dimensionless flexural stiffness, number and length of the steps, effect of the driving force and the reaction moment exerted at the central front bearing. The calculations enable optimization (for maximum stiffness) at the chuck for short overhang spindles such as those of lathes.

The most effective design parameter is the optimum bearing spacing, demonstrated in the study by evaluating the exact analytical solution of the derived equations.
Study into the Measurement and Prediction of Penetration Time during CO2 Laser Cutting Process
Authors: Yilbas B S , Davies R , Yilbas Z
Published: February 2007

The present study examines the measurement and prediction of the penetration time during CO2 laser cutting of mild steel workpieces at various pressures of oxygen and argon-oxygen mixtures. Three different measurement techniques are introduced, namely optical, thermocouple and wire methods. The Fourier heat transfer equation is examined and a quasi-steady solution is obtained for the temperature distribution inside the material. The data available for the cutting quality are then related to the penetration time.
Vibration Monitoring of the Internal Centreless Grinding Process Part 2: Experimental Results
Authors: Lacey S J
Published: February 2007

Experimental results of grinding tests are presented showing how both forced and self-excited vibration occurring during the internal centreless grinding process can be associated with deterioration in workpiece finish and form. Mechanical vibration from rotating machine elements and wear of the dressing diamond and grinding wheel are all investigated. It is shown how a deterioration in these parameters can be associated with characteristic vibration signatures, and a good correlation obtained with the models proposed in Part 1 of this paper.
Manufacturing Process Selection and Costing
Authors: Allen A J , Swift K G
Published: February 2007

The design of a component, its material and method of manufacture determine its quality and cost. In this paper a technique is introduced that can be used in the early stages of the design process for the purposes of manufacturing process selection and costing. The work has been applied in industry and its performance, in terms of its ability to predict costs, is described; its implementation as a knowledge-based system integrated with the automated draughting process is also discussed.
Parting Lines and Parting Surfaces of Injection Moulded Parts
Authors: Tan S T , Yuen M F , Sze W S , Kwong K W
Published: February 2007

This paper presents a computer method for automatic determination of a parting line and the corresponding parting surface of a part for injection moulding. The method requires the input of a solid model of the part and the preferred injection mould parting direction. The outputs are the computed parting line and parting surfaces for the specified parting direction, which would allow the resulting mould halves to be configured. The method also detects interlocking surfaces for the specified parting direction, in which case side cores are required.
Automating Quality Systems
Authors: Tannock J D T , Wort R G , Savage B M
Published: February 2007

This paper proposes a strategy for the automation and integration of quality systems for manufacture. It describes a systematic structured quality system design and improvement process, together with a comprehensive approach to automation in data collection and quality data management; within a framework—compatible with the themes of Total Quality Management—which a manufacturing company may use to automate quality control operations.
Manufacturing of Thin Rectangular Plates by Explosive Compaction of Copper Powder
Authors: Mamalis A G , Gioftsidis G N , Prohaszka J
Published: February 2007

The explosive compaction of spherical copper powder to fabricate thin rectangular plates using a multi-die configuration is considered. The effect of shock wave front developments through the powder body on microstructural changes, bonding between particles and fracture damage of the compact is examined and discussed. The ‘soundness’ of the compact is examined with respect to the die design used at the powder/die cavity interfaces of materials of different mechanical impedance. Improved workability of the compact subjected to subsequent compressive processing, for example, rolling at high reductions, is reported.
Lubrication in Cold Strip Rolling in the ‘Mixed’ Regime
Authors: Sutcliffe M P F , Johnson K L
Published: February 2007

Lubrication in metal rolling in the mixed lubrication regime has been considered. An inlet analysis has been used to calculate the film thickness and area of contact ratio in the bite, taking into account the effect of roughness on the pressure build-up and the effect of the bulk deformation on the crushing of asperities. The film thickness with rough contact is most strongly dependent on the variables which determine the film thickness with smooth contacts, that is, roiling speed, oil properties and inlet geometry, but the effect of yield stress, strip thickness, roughness geometry and inlet tension are also examined. In a separate calculation hydrodynamic theory has been used to estimate film thickness under the ‘contact’ areas. These two calculations have been combined with recent measurements of oil properties to estimate friction-slip relations when rolling thin aluminium foil. These calculations provide quantitative information on friction conditions to help model the rolling process and to estimate the strip surface quality.
Force Data Acquisition Using Computer Process Monitoring
Authors: Arsecularatne J A , Hinduja S , Barrow G
Published: February 2007

This paper addresses the problem of calculating the optimum cutting conditions for a turned component made of a material for which the constants and exponents in the force equations are not available. The problem is solved by using an approximate method to calculate the cutting conditions for the first component in the batch, and monitoring the motor armature current-signals during machining of the first component in order to calculate the tangential and feed force components. In between the time required to unload the first component and load the second component, the system evaluates the constants and exponents in the force equations and uses them to calculate the optimum cutting conditions for the second and subsequent components in the batch. A comparison between the predicted and experimentally measured forces shows good agreement.
Design Guidelines for Predicting Contact Loss in Revolute Joints of Planar Linkage Mechanisms
Authors: Earles S W E , Seneviratne L D
Published: February 2007

Contact loss at clearance joints of mechanisms gives rise to system degrading impacts when contact is remade. Traditional design tools such as the zero-clearance analysis are inadequate to predict contact loss. Theoretical analyses which have the ability to predict contact loss, such as the massless link model, are complex, computationally expensive and need further refining. This study employs the massless link model, which models the joint clearance of mechanisms as an extra degree of freedom, as a vehicle to study the phenomenon of contact loss. The equations of motion for a four-bar mechanism with a clearance joint are derived and the equations are uncoupled to yield an expression for the clearance joint force magnitude in terms of the system kinematic variables and the clearance link response. Hence it is shown that there exists a single zero-clearance dimensionless parameter which governs the contact loss condition at the clearance joint. In particular it is shown that contact loss will occur if this parameter is equal to or greater than unity. The condition for predicting contact maintained is less clearly defined, as it contains a quantity not easily evaluated. It is argued that the Earles and Wu empirical criterion (γ/R) for maintaining contact can be applied with reasonable confidence, leaving a region of uncertainty which it is considered will in general be relatively small. The empirical parameter γ/R is contained within the theoretical dimensionless parameter derived for predicting contact loss.
Thermal Behaviour of a Twin Axial Groove Bearing under Varying Loading Direction
Authors: Gethin D T , El-Delhi M K I
Published: February 2007

An experimental investigation and numerical model development to predict the behaviour of a journal bearing subjected to different loading direction is described. The numerical model predicts significant thermal excursions under conditions of extreme load and speed, and these trends are confirmed by experimental observations. The experimental results show that the oil grooves are not effective in providing cool lubricant when they are positioned in the loaded part of the film. The numerical model suggests that at a prescribed eccentricity ratio, a very significant load increase can occur (threefold) for a small change in loading direction. Additionally, predicted side flow is very load direction dependent while bush torque reaction is not; these trends are confirmed by experimental observation.
The Influence of Piezoviscosity on the Minimum Film Thickness in Heavily Loaded Elastohydrodynamic Point Contacts
Authors: Hooke C J
Published: February 2007

The lowest film thicknesses in heavily loaded point contacts occur in a band around the rear of the contact. The minimum lies either at the centre of this band or at its ends, near the sides of the conjunction. The clearances in the two regions vary independently with changes in contact geometry and operating conditions, but for relatively narrow contacts and for higher loads the clearance at the contact sides is smaller than on the centre-line. This paper examines how this side clearance alters, under heavily loaded conditions, with changes in piezoviscosity.
Finite Element Study of Residual Stresses in a plate T-Joint Fatigue Specimen
Authors: Mok D H B , Pick R J
Published: February 2007

Using the finite element code ABAQUS to make numerical predictions, this paper studies the crack shape development and thickness effects on a series of welded plate T-joint fatigue specimens. It was found that redistribution of the residual stress only occurs in a small region near the weld toe, the extent depending greatly on the magnitude of the applied load.
Method of Solution of the Time-Dependent Fully Developed Energy Equation
Authors: Cotton M A , Jackson J D
Published: February 2007

In the early 1960s Hall, Jackson and Price published a paper in the Journal of Mechanical Engineering Science in which they obtained the fundamental solution of the fully developed energy equation in steady flow. Some attention in the same research group is now turned to the measurement and calculation of transient convective heat transfer and it is shown here that the analysis of Hall et. al. may be extended to such time-dependent flows. The analysis is restricted to forced convection conditions but applies equally to laminar and turbulent flows.
Algorithms for a Versatile Two-Degree-of-Freedom Robot Wrist
Authors: Stammers C W
Published: February 2007

Two-degree-of-freedom wrists are examined with the objective of formulating designs which will allow three-degree-of-freedom performance by means of repeated use of the two available freedoms. Both axes must either be fixed with respect to the arm or move with the wrist. Friction drive designs are examined. Algorithms are presented for the achievement of the objective. There is a performance penalty involved, which for some manoeuvres is appreciable, but which for others is negligible.
Calculation of the Three-Dimensional Behaviour of Spherical Solid Particles Entrained in a Radial-Flow Impeller Pump
Authors: Minemura K , Uchiyama T
Published: February 2007

Equations of motion of solid particles in a pump impeller having a low specific speed were solved numerically in the flow field obtained with assumptions of an inviscid and incompressible three-dimensional potential flow, and general movements of solid particles in the pump were clarified. Trajectories of the sand particles and manganese ores, with diameters ranging from 1 to 5 mm, were obtained for different flow capacities. The positions and velocities with which the particles impact on the boundary surface of the pump were also discussed in order to estimate erosion damage in pumps.
An Interpolation Procedure for the Minimum Film Thickness in Point Contacts
Authors: Hooke C J
Published: February 2007

Most engineering point contacts operate in, or close to, the elastic piezoviscous regime. A general interpolation procedure is presented by which the minimum film thickness in any such contact may be estimated. This procedure matches all existing numerical and experimental results with high accuracy. Design charts are provided and these enable the minimum film thickness to be read directly and also allow the effect of changes in contact geometry and operating conditions to be assessed.
Fracture Mechanics of Composites Failure
Authors: Williams J G
Published: February 2007

A review of how fracture mechanics can be applied to the various fracture modes observed in composites is given. It is shown that rather conventional methods may be used for short-fibre composites but that oriented laminates undergo delamination, often parallel to the applied loads, and energy release rate methods must be used to analyse these failures. The importance of delamination toughness in determining composite behaviour is emphasized and details of the various test methods and analysis techniques are given. Finally, some discussion of the more complex failures seen in cross-ply laminates is presented.
Crack Size Limit and its Effects on the Shape of Local Yielding Zone at the Crack Tip
Authors: Chow C L , Lu T J
Published: February 2007

The validity range of one single parameter or K-characterization for the entire crack-tip stress and deformation fields under small-scale yielding conditions is shown to be surprisingly small. As a vehicle for demonstration purposes, an inclined crack buried in an infinite plane plate subjected to biaxial remote loadings is first analysed. The standard singular fields are found to be inadequate in characterizing, to within some reasonable accuracy, such important parameters in controlling such fracture phenomena as the hydrostatic stress, the maximum shear stress and the Mises equivalent stress or the size of the plastic zone at a crack tip. They also fail to describe, even roughly, the experimentally observed shape changes of the plastic zone under both plane stress and plane strain conditions. If, however, the non-singular term in Williams' eigenfunction series expansion is retained instead of being omitted arbitrarily, it is then found that such shape changes can be predicted quite adequately. Comparison with previous results based on elasto-plastic FEM analysis and inelastic modelling is favourable. Influences of specimen geometry configuration on the plastic zone shape are illustrated. Related topics such as the crack initiation angle prediction and fatigue crack propagation description are also discussed.
Natural Frequencies of a Cam Mechanism
Authors: Sadek K S H , Rosinski J , Smith M R
Published: February 2007

A cam mechanism with sliding follower was run using two sets of linkages. The first, which was made of solid sections, resulted in large-amplitude vibration on the acceleration record. The second, made of hollow sections, gave acceleration records showing less vibration. Vibration analysis tests were carried out using an impact test and a white-noise test to compare the natural frequencies of the two mechanisms.

The paper suggests that the design of cam-driven mechanisms should ensure that their lowest natural frequency is higher than the highest frequency with a significant component in the acceleration spectrum of the follower. A simplified method of calculating the natural frequencies is appended. The experimental procedures are described and the pitfalls are highlighted.
Central Film Thickness Charts for Elliptical Contacts
Authors: Sutcliffe M P F
Published: February 2007

Central film thickness charts are constructed for circular contacts and for elliptical contacts with entrainment along the major axis.
Some Concepts and Conceptual Devices for Exergy Analysis
Authors: O'Toole F , McGovern Eur Ing J A
Published: February 2007

The main concepts of exergy analysis are outlined with special emphasis on the fact that exergy can be transferred and transported and on the distinction between work and useful work. The exergy transfers associated with work and with heat are described. The relationship between so-called flow exergy and non-flow exergy is explained. Three conceptual devices which can be inserted at an analysis boundary are presented. These achieve mechanical separation between the systems on either side of the boundary so that an exergy transfer equivalent to the net exergy transferred and transported across the boundary can be visualized and evaluated. The first conceptual device can be used where heat transfer occurs at a boundary, the second where a steady flow fluid stream enters and leaves a system, and the third where air and fuel streams enter and flue gases leave a combustion system.
Fast Motion Control of Robot Manipulators with Inclusion of Actuator Dynamics
Authors: Pan D , Sharp R S
Published: February 2007

This paper contains an extension of a previous work (18) to include actuator limitations. A mathematical model for describing the complete dynamics of a robot manipulator is obtained by combining the non-linear and coupled dynamic equations of motion of a manipulator linkage with those for its actuators. The combined equations are then piecewise linearized and discretized to form a set of state difference equations by which a mathematical basis is provided for computer control and simulations. The adaptive control scheme and on-line computational scheme which were proposed in reference (18) are employed to drive robot manipulators to follow high-speed trajectories specified by continuous time functions. These schemes are briefly described in this paper. The control strategy involves a combination of feedforward and feedback control. The control delay associated with time taken for on-line computation is eliminated by a state-and-control prediction scheme. The emphasis in this paper is on the effectiveness of the control strategy and the computational scheme proposed and on the influences of actuator dynamics. Simulation results are compared with those of reference (18), in which perfect actuators were assumed. The inclusion of actuator dynamics in the modelling is shown to influence the controller design substantially. With appropriate controller design procedures, the tracking performance of the robot is shown to be very good.
Research in Mechanical Seals
Authors: Nau B S
Published: February 2007

Current knowledge of the factors affecting the performance of rotary mechanical seals is reviewed in depth under the following main headings: seal performance, operational considerations, materials, face topography, fluid film lubrication, film vaporization, face contact conditions, structural analysis and vibration and runout.
Steady State Analysis of Pneumatic Servo Drives
Authors: Pu J , Weston R H
Published: February 2007

This paper introduces new approaches and design models aimed at determining the steady state behaviour of pneumatic servo drives. Relationships characterizing actuator velocity and chamber pressure with respect to valve displacement are established. Certain parameter ratios are defined and a novel analytical solution is offered, which may provide the basis of a better and more useful design methodology than conventional graphical methods. The observations and analysis are applicable to both linear (symmetric and asymmetric) and rotary drives controlled by either a single five-port servo valve or two independent three-port servo valves.
A Study of Turbulent Flows in Pipe Bends
Authors: Al-Rafai W N , Tridimas Y D , Woolley N H
Published: February 2007

An experimental and numerical study of turbulent air flow in circular section pipe bends was carried out in order to determine the influence of bend curvature on the flow.

Two bends were used, with inside diameters of 43 mm and curvature ratios of 1:13.95 and 1:6.98. The corresponding Dean numbers were 9138 and 12919. The Reynolds number for both cases was 34132.

Measurements of mean streamwise and r.m.s. velocities were made using laser Doppler anemometry. Numerical modelling was based on the commercial computer package ‘PHOENICS’, employing a k-ɛ turbulence model, standard wall functions and a three-dimensional elliptic solution procedure.

The results showed that the secondary flow as more prevalent in the smaller bend. In view of certain simplifying assumptions in the theoretical model, encouraging agreement between experimental results and numerical predictions was obtained.
The Simplification of Vehicle Harness Designs Through the Application of Active Junction Boxes
Authors: Evans J H
Published: February 2007

This paper reviews the current status of multiplexing and networking systems, introduces the concept of junction boxes and active junction boxes and then describes a specific application of the technique to vehicle harness design.
The Uses of Composite Materials in the Design and Manufacture of Formula 1 Racing Cars
Authors: O'Rourke B P
Published: February 2007

In recent years a new application for advanced composite materials has been in the construction of load-bearing components for Formula 1 racing cars. Their use has been progressively extended and they currently comprise a major part of the vehicle assembly for all competing Formula 1 designs. Here the experiences gained with these materials at Williams Grand Prix Engineering are described. The initial interest in this technology was for optimization of structural efficiency. A wide range of component design criteria are covered and advantages have also been found in the areas of strength, impact performance, geometric accuracy and speed of manufacture.
The Injection Equipment of Future High-Speed DI Diesel Engines with Respect to Power and Pollution Requirements
Authors: Dolenc A
Published: February 2007

The development of high specific output DI diesel engines started at the low-speed end some 50 years ago primarily for marine and traction applications. Movement towards the high-speed end has been slow but steady with the majority of truck engines being very conservatively rated (Fig. 4). There has been recent major effort on the automotive car and light commercial vehicle diesel application leading to lightweight DI diesel engines with an engine speed of 4000–5000 r/min and a rated power of 50 kW/litre displacement. These are expected to be on the market in a short period of time. The key point of this development has been the injection equipment including combustion control. In this area the use of modulated injection has the possibility of solving power and pollution requirements.
Evaluation of 2, 4-Dithiomalonamides as Extreme Pressure Additives in the Four-Ball Test
Authors: Singh T , Singh R , Verma V K
Published: February 2007

Four-ball tests using 12.7 mm diameter steel bearing balls were conducted to evaluate the load-carrying and extreme pressure properties of admixtures of paraffin oil with 1, 5-diaryl-2, 4-dithiomalonamides and a sulphur-phosphorus commercial additive (0.5 per cent wt/vol.). 1, 5-Di-p-methoxyphenyl-2, 4-dithiomalonamide exhibiting wear scar diameter and friction coefficient values of 0.58 mm and 0.058 at 100 kgf (ISL) and 2.18 mm and 0.077 at 500 kgf as compared to the values of 2.05 mm and 0.022 at 56 kgf (ISL) and 2.73 mm and 0.43 at 100 kgf for paraffin oil appeared to be most effective. The surface topography of the wear scars were examined by scanning electron microscope.
The Modelling of Engine Heat Conduction Using Axisymmetric Models
Authors: Mason T P , Smart J
Published: February 2007

A full finite element analysis of the heat transfer in an engine is often expensive in both computer and manpower costs. Hence the use of simplifying assumptions is often necessary.

In this paper the heat conduction in an automotive diesel engine cylinder block has been examined using both three-dimensional and two-dimensional axisymmetric models to determine whether it is feasible to use the simpler axisymmetric models.

It is found that a series of axisymmetric models gives a good approximation to the three-dimensional model with a significant saving in computing costs. The axisymmetric models are far easier to construct, giving a quicker turn-round time and allowing more design ideas to be investigated.
Parametric Modelling of Internal Combustion Engine Systems for Design Optimization
Authors: Mucino V H , Wang W G , Smith J E
Published: February 2007

In this paper, the development of a general approach is presented, aimed at the parametric design modelling of internal combustion engine systems. This approach allows optimization procedures to be applied which yield optimum characteristics of the engine in terms of single- or multi-performance criteria and under specific requirements of speed and power.