bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelling and Simulation of the Operational and Information Processing Functions of a Computer-Integrated Manufacturing Cell
Authors: Bartlett H , Wong R
Published: February 2007

This paper investigates the information processing function of a computer-integrated manufacturing (CIM) system, which is usually neglected by engineers when they study the performance of a manufacturing system. The feasibility of developing a complete simulation model which would include both the operational and information processing functions is therefore considered. In order to achieve this, a typical pick-and-place manufacturing cell was considered in which 46 devices were connected to a local area network (LAN). Two independent simulation tools, SIMAN* and L-NET†, were used in order to develop the complete model.

The model was evaluated and used to study the performance of the pick-and-place cell using different communication protocols such as the IEEE 802.3 carrier sense multiple access with collision detection (CSMA/CD), IEEE 802.4 token bus and the IEEE 802.5 token ring. Results presented in this paper show that with careful design and simulation it is possible to develop a complete model which includes both operational and informational processing functions. Although the example of the pick-and-place cell is relatively simple the technique adopted could be applied to any CIM system.

Results have also shown that for the pick-and-place cell considered in this paper an IEEE 802.3 CSMA/CD protocol operating at 10 Mbps would guarantee access to the network within the shortest station processing time.
Research Developments in Rapid Prototyping
Authors: Dickens P M
Published: February 2007

Rapid prototyping is a new name for a group of techniques that have largely been developed during the last ten years. They involve producing parts by adding layers of material on top of each other to build a complete model. The research involved on these techniques is mainly being undertaken in North America, Europe and Japan, with many new advances occurring each year. There is still much scope for work in developing new rapid prototyping techniques and applications for the parts produced from them. The impact of these techniques on manufacturing is only just being recognized, but during the next few years academia and industry will accept them as a valuable addition.
A Novel Process Planning Architecture for Product-Based Manufacture
Authors: Maropoulos P G
Published: February 2007

This paper presents a new process planning architecture which is compatible with the integrated product and process development of concurrent engineering and interfaces with production control. The architecture consists of three levels, namely aggregate, management and detailed (AMD), which are defined according to the granularity of process modelling considerations, the interfacing requirements with design and production control, and the natural time cycle of the corresponding activities. The essential functionality at each level is also discussed and the new technology requirements are identified. The modularity of AMD will allow the generation of flexible, customized process planning systems to meet specific industrial requirements, enhance the operation of modules at each level and reduce the overall system complexity. However, the most important benefits offered by the AMD architecture are the establishment of time-dependent interfaces with design and production control and the formation of a modular structure that will facilitate the development of future generation, distributed process planning systems.
An Examination of the Application of the UMIST Quality Improvement Framework
Authors: Dale B G , Prapopoulos M
Published: February 2007

This paper examines the application of the UMIST generic quality improvement framework to a representative sample of companies residing within the Trafford Park industrial area. The 14 companies were introduced to the framework through seminar and syndicate work and two frameworks were developed to suit the needs of both large and small companies respectively. The frameworks are reasonably similar but the representatives of the larger companies tended to be more specific about some elements of the framework. The small companies did not see the need to carry out formal planning in the same manner as large companies but, on the other hand, there is more of a requirement to concentrate on basic issues such as a complaints procedure and company newsletter. The service companies perceived a grey area between some of the elements in the systems and techniques and measurement and feedback sections of the framework. It is also apparent that service companies have more difficulties with the application of quality management tools and techniques and performance measurements than their manufacturing counterparts.
Non-Uniform Motion by Mechanical Means
Authors: McGarva J R
Published: February 2007

In this paper a methodology for designing mechanical non-uniform motion generators is presented. The basic requirements for four-bar and six-bar linkages are established and it is shown how the performance can be evaluated by harmonic analysis applied to the output angular velocity function. A means of creating and searching a library of mechanisms based on normalized output functions is presented. B-spline curves are used as a means of defining a desired performance and it is shown how minimum acceleration can be achieved with continuity in the derivatives. Finally, a means of increasing the quality of motion transmission in the selected mechanisms is given. The techniques are used to synthesize a six-bar linkage.
Prediction of Chip Flow Direction and Cutting Forces in Oblique Machining with Nose Radius Tools
Authors: Arsecularatne J A , Mathew P , Oxley P L B
Published: February 2007

A method is described for calculating the chip flow direction in terms of the tool cutting edge geometry and the cutting conditions, namely feed and depth of cut. By defining an equivalent cutting edge based on the chip flow direction it is then shown how cutting forces can be predicted given the work material's flow stress and thermal properties. A comparison between experimental results obtained from bar turning tests and predicted values for a wide range of tool geometries and cutting conditions shows good agreement.
Technology Management: A Process Approach
Authors: Gregory M J
Published: February 2007

This paper proposes a framework for the management of technology based on process thinking. Technology management has traditionally focused on product-oriented research and development (R&D) and assumed a linear model of innovation, starting with science and progressing through technology and design to production. It is now increasingly recognized that this linear approach is only one of many and that production as well as product development can be a powerful and protectable source of competitive advantage.

The management of production operations has improved significantly over recent years. Manufacturing companies have begun to replace conventional functional and hierarchical organizations with process approaches to operational activity and management decision making. Such approaches can lend structure and transparency to business operations, link activities more clearly to customer requirements and allow wider involvement of staff and collaborators. It is argued here that the explicit management of product and production technologies, using process thinking, can yield similar benefits.

The paper links traditional views of technology management including R&D management, innovation and new product introduction with competence ideas from strategy and a resource perspective from economics. A preliminary ‘process framework’ for technology management is proposed, covering the range of activities from identification to protection. The framework is demonstrated, and its potential benefits explored, in the context of a pilot study of manufacturers in the measuring equipment and domestic appliance industries in Europe, the United States and Japan.
On-Line Monitoring of the Electric Arc-Spraying Process Based on Acoustic Signatures
Authors: Kovacevic R , Mohan R , Murugesan M , Seybert A F
Published: February 2007

Electric arc spraying (or metal arc spraying) is a process that deposits metal particles on suitable substrates using two consumable wire electrodes. The high-temperature arc formed between these electrodes in an atomizing jet of air produces small molten particles which are used to coat the substrate. The contribution of the process parameters and their interactions on the coating thickness is analysed using Taguchi's design of experiments. The time and frequency domain sound signals generated during the process are utilized to characterize the spraying phenomenon. Stochastic modelling of acoustic signals forms the basis for a closed-loop control mechanism of the arc-spraying process proposed for the first time. Experimental proof of the Gaussian nature of the deposition profile is provided and a mathematical approach has been suggested to obtain a uniform deposit thickness in a single pass.
The Role of Human Factors and Safety Culture in Safety Management
Authors: Booth R T , Lee T R
Published: February 2007

The paper describes the evolution of safety management and the part played by human factors in accident causation. It identifies the key elements of effective safety management and suggests that a crucial determinant of good safety performance is the safety culture of the organization. A plan is outlined for reviewing and improving safety culture with the support of a detailed safety culture promptlist.
Competitiveness
Authors: Small B W
Published: February 2007

The subject of this paper is competitiveness. The author sets out to show that competitiveness determines our economic freedom and company profitability and begins with really knowing the market and responding to demand. Becoming fully competitive is a task demanding total commitment and a holistic approach, with success depending on seven key dimensions of competitiveness.
Modelling Flexible Sheets for Automatic Handling and Lay-up of Composite Components
Authors: Newell G C , Khodabandehloo K
Published: February 2007

Automating the manufacturing process associated with composite components from prepreg presents new engineering challenges. To design, implement and operate machinery to handle and lay-up prepreg sheet material requires a clear understanding of the processes involved. Manipulation of sheet material is an integral part of the lay-up procedure. This paper presents the main automation issues concerning the production processes and defines a mathematical model for predicting the shape of prepreg sheets for the purposes of manipulation. This provides an aid towards the control of shape during the process of lay-up. Critical mould parameters, which determine prepreg sheet shape, are presented. Lay-up trajectories for a multi-arm robotic system have been derived, utilizing the models formulated. Practical trials with an existing multi-arm robotic system have proved satisfactory control of the process.
Extending Laser Bending for the Generation of Convex Shapes
Authors: Arnet H , Vollertsen F
Published: February 2007

A summary about the present process understanding of the laser bending technology is given. Three different bending mechanisms are distinguished. Experimental results showing that at certain parameters an instability behaviour can occur are discussed. A bending mechanism is suggested which explains the stability behaviour. It is shown that laser bending can be extended in order to generate convex shapes, which means a bending away from the laser beam. The possibility of bending towards the laser beam or of bending away from the laser beam opens new ranges of applications, two of which are introduced in this paper.
Cycle Time Reductions in Resin Transfer Moulding Using Microwave Preheating
Authors: Johnson M S , Rudd C D , Hill D J
Published: February 2007

Resin transfer moulding (RTM) offers a potential manufacturing source of high-volume, fibre-reinforced plastic (FRP) components for the automotive industry. Currently, market development is inhibited by long moulding cycle times which are dominated by the effects of mould quench. Preheating of the thermosetting resin prior to injection would reduce these effects, leading to shorter mould filling and curing times. This paper characterizes the thermal cycle in RTM and outlines the application of microwave technology for resin preheating. Batch preheating of preactivated resin systems is discussed and the development of an in-line microwave resin preheater is described for uncatalysed and catalysed resin systems under steady flow conditions. The integration of an in-line preheating system within a demonstration RTM facility is described and the effects of preheating on the thermal cycle are presented.
Quantification of Energy Absorption Capability in Abrasive Water Jet Machining
Authors: Momber A W , Kovacevic R
Published: February 2007

The paper contains a mathematical model for the estimation of the energy absorption capability of materials during abrasive water jet machining based on an energy balance inside the workpiece. A parameter χ(h) is defined to describe and calculate the energy absorption capability. A method for the estimation of this parameter is developed based on a parabolic striation model. It is shown that the energy absorption depends on the depth of cut following a second-order equation. The relation between the relative depth of cut h/hmax and the energy absorption capability χ(h) can also be described by a second-order equation. For such materials as aluminium, cast iron and stainless steel a critical point of abrasive water jet energy absorption is detected at a depth of cut of h = 0.52hmax, which corresponds to a striation angle of about 75°.
Continuous Monitoring of Smith Shocks after Lubrication Failure
Authors: Smith J D
Published: February 2007

Contacting surfaces can give rise to short pressure pulses (Smith shocks) when asperities interact and the resulting high-frequency vibrations, detected by accelerometers, can indicate surface distress to allow condition monitoring. Previous work had been limited by the test technique used so in this work vibration was recorded directly to computer memory to give a clearer idea of vibration patterns after failure of lubrication.
Theoretical Evaluation of the Effects of the Impeller Entrance Geometry and of the Incident Angle on Cavitation Inception in Centrifugal Pumps
Authors: Ardizzon G , Pavesi G
Published: February 2007

A method, based on quasi three-dimensional analysis, of describing pump cavitation behaviour is proposed. Cavitation performance is related to impeller entrance design and the influence of the angle of attack of the leading edges on the flow is studied. Coefficients are derived from the pressure drop due separately to the vanes and shroud. The influence of incident angle on cavitation is shown as a function of the blade geometry and discussed.

By comparison with experimental data on centrifugal pumps, it is shown that the present model can simulate the characteristics of inception cavitation at design and off-design conditions.
A Modified Selective Precision Synthesis Technique for Planar Four-Bar Rigid-Body Guidance
Authors: Kim K-Y , Kwak B-M
Published: February 2007

The selective precision synthesis (SPS) technique is modified by adopting the displacement matrix approach and using binary links as basic elements. This modified SPS (MSPS) can thus be applied to the synthesis of slider-crank mechanisms as well. With the introduction of ‘maximum allowable angular deviation’, the mechanism construction error (MCE) at a design point can be eliminated. The link length adjustment is also found to be a useful tool for the case of infinite MCE. The proposed MSPS is shown to be logical and effective by a practical design example.
A New Simplified Approach to the Kinematic Analysis and Design of Epicyclic Gearboxes
Authors: Fogarasy A A , Smith M R
Published: February 2007

The present paper introduces a much simplified method for the kinematic analysis of epicyclic gear drives. It is based on the concept of the existence of only two basic building blocks and their kinematic constraint equations. These can easily be found by inspection of the relevant kinematic structural diagram. A new type of notation is used which is simpler and more versatile than those of previous methods and is adaptable to depicting the kinematic alternatives of any particular drive without the need for drawing structural diagrams.
Forward Positional Analysis for the General 4–6 In-Parallel Platform
Authors: Liao Q , Seneviratne L D , Earles S W E
Published: February 2007

Presented is the forward positional (kinematic) solution for the general case of the 4–6 in-parallel platform mechanism; in particular, the spherical joints of the moving and base platforms are not restricted to lie in planes, but can be freely chosen. The forward positional analysis consists of 13 equations which are reduced to a single thirty-second order polynomial equation in one unknown variable. This new equation is numerically solved and validated by substituting the 32 roots into the 13 forward positional equations. The new analysis is also used to solve an example, with a set of known results from a previously published paper, in which a special case of the 4–6 in-parallel platform is considered; the results are in exact agreement. For a number of general platform and actuator inputs a maximum of 24 real solutions have been found. One example is illustrated.
Mechanical Analysis of a Thin Solid Circular Plate Deflected by Transverse Periphery Forces and by a Central Load
Authors: Dragoni E , Strozzi A
Published: February 2007

A thin, solid, circular plate deflected by a number of transverse, concentrated, periphery forces, not necessarily angularly equispaced or equally oriented, and sustaining a central, transverse, equilibrating load, is mechanically analysed via a purely flexural model. This problem is interpreted as a angularly dephased combination of a relatively simple model. This fundamental scheme consists of a plate loaded by a single periphery force, by a central load of equal intensity and opposite direction, and by a sinusoidal periphery line loading whose wavelength equals the plate border and whose intensity renders the plate loading self-equilibrated. When a sequence of basic schemes, possibly referring to loads of different intensity, is combined, respecting the condition that the resultant of the periphery loads is equilibrated by a central force alone, the sinusoidal load effects vanish and the title problem is recovered. A series solution in terms of plate deflections is obtained for the basic model, whose coefficients are analytically evaluated via a computer algebra package. The series sum is expressed in finite terms involving the dilogarithmic function, valid over the whole plate region. In particular, the series is summed in analytical form for the whole plate periphery, along which the boundary deflections are expressed in closed form.
The Effect of Inclined Loads on the Large Deflection Behaviour of Elastoplastic Work-Hardening Straight and Pre-Bent Cantilevers
Authors: Liu J H , Atkins A G , Pretlove A J
Published: February 2007

A theoretical analysis is presented to examine the effect of inclined tip load on the large deflection behaviour of an elastoplastic cantilever with linear work hardening. The cantilever is either initially straight or pre-bent to a tip angle of ø (see Fig. 1). When the load is large enough, the overall deformation of a pre-bent cantilever is smaller than that of an initially straight one as a result of the influence of the guided end. The maximum plastic region spm in the cantilever increases with the force angle ø and the plastic-elastic modulus ratio α, but decreases as the beam flexibility parameter β increases. Some unstable deformation may occur in the initially straight cantilever when ø > π/2 and this depends on the value of α and β. Reasonable agreement is obtained between the theoretical analysis and experimental results.
An Experimental Investigation into Bearing-Induced Spindle Vibration
Authors: Aini R , Rahnejat H , Gohar R
Published: February 2007

This paper describes experiments carried out to investigate the frequency response of a grinding machine tool spindle supported by preloaded angular-contact ball bearings. The experimental apparatus includes a loading device to simulate grinding head radial loads. The frequency spectra obtained show bands of frequencies associated with the ball passage frequency. The spectra also include bounce and rocking vibration modes of the assembly, where the supporting bearings act as non-linear springs.

Good correlation of the dominant frequencies was obtained with the results of the theoretical models published elsewhere.
Mechanical Hysteresis in Force Transducers Manufactured from Precipitation-Hardened Stainless Steel
Authors: Allgeier T , Evans W T
Published: February 2007

A non-linear, anelastic stress-strain relationship, hereafter called mechanical hysteresis, which leads to a significant error in the output signal of electrical resistance strain gauge force transducers, has been confirmed to be a general phenomena in precipitation-hardened stainless steels. The mechanism of mechanical hysteresis has been found to be due to the material behaviour; nevertheless, the design of the force transducer and details of the electrical resistance strain gauges could impose further minor effects on the size of the error. Some of the secondary influencing factors (for example loading and mounting details) have been eliminated in the course of the investigation.

Using a specially developed heat treatment process, it has been possible to substantially reduce the hysteresis error, which in turn improves the force transducer accuracy.
Simple First-Order Models for Surging in Pump and Compressor Systems
Authors: Anderson A
Published: February 2007

For turbomachine surging arising from interaction between the turbomachine and duct system discharge-pressure characteristics, simple lumped-parameter models for duct inertia, elasticity and losses are used to review existing stability criteria for and descriptions of the phenomenon. Conventional descriptions are shown to relate specifically to lumped-inertia models, whereas different conditions for stable operation are given by lumped-elasticity models. For systems with both inertia and physically discrete elasticity, the stability criteria depend on system configuration and hence such models are not suitable for application to distributed systems. An approach to distributed systems to overcome this limitation is suggested.
Optimized Design of Vibration Controllers for Steady and Transient Excitation of Flexible Rotors
Authors: Keogh P S , Mu C , Burrows C R
Published: February 2007

Controller designs for the attenuation of rotor vibration are investigated. Disturbance inputs leading to vibration are classified and related to control forces and defined control states. Optimization based on the H∞ norm is then used to minimize the influence of forcing disturbances, modelling error and measurement error. The practicalities of applying the method to an experimental rotor-bearing system, with hardware constraints on controller order, are stated. The controller was implemented experimentally to conduct steady state and mass loss tests. Steady synchronous, non-synchronous and transient vibration attenuation was demonstrated. It was also shown that measurement error, caused by shaft surface roughness, can be incorporated into the controller design without the need to remove the roughness component from the measured displacement signals. If the roughness influence is not included in the design and the uncontrolled vibration is small, unnecessary control forces may result, causing an increase in vibration.
Identification of Fluid Power Component Behaviour Using Dynamic Flowrate Measurement
Authors: Watton J , Xue Y
Published: February 2007

An identification concept is developed utilizing direct measurement of the transient flowrate and pressure to determine the dynamic characteristics of fluid power components. The fundamental experimental approach is discussed and applied to a range of sizes of a bladder-type accumulator and also to a single-stage pressure relief valve. The gas charging characteristic of the accumulator was determined for three different sizes and during dynamic operation. It is shown how the nitrogen gas index of compression varies during operation and a relationship between the index and instantaneous flowrate is proposed. Measurements obtained with the pressure relief valve were used to identify its dynamic impedance in the frequency domain via time series analysis and transformation. The predictions are compared with a linearized mathematical model showing good correlation over a wide frequency band. A particular feature was found to be the use of the impedance magnitude-frequency asymptotes for validation of the steady state pressure-flowrate characteristic.
Estimation of the Static Load Distribution Factor for Helical Gears
Authors: Smith J D
Published: February 2007

The factor by which the maximum load per unit length of gear tooth exceeds the nominal loading is of major importance when estimating the stresses on gears, but there is little information about the values that are to be expected with accurately made modern gears. A method for relatively simple computation of the effects of misalignment, profile and helix variations is given, together with typical results that show values of KH about 3, much higher than might be expected or predicted from BS 436.
Effect of Thread Form on the Strength of Ceramic Bolts
Authors: Gane N , Polivka F
Published: February 2007

The strength of various designs of screw thread in partially stabilized zirconia (PSZ) bolts has been measured. It was found that the thread geometry usually used for metal fasteners and connections is not the optimum for a brittle ceramic material such as PSZ. An increase in the flank angle of the thread from the normal 60° to 90° can produce a 40 per cent increase in strength. The results are discussed in terms of the stress concentration factor acting at the notch root of the thread and the tensile strength of PSZ. This stress concentration or notch embrittlement factor reduces the strength of the threaded connection in a brittle material, compared to that of a metal with the same tensile strength. In the present experiments a stress concentration factor of between 2 and 4 was observed. This factor is combined with Weibull statistics to obtain safe working stresses for various designs of screw thread in PSZ. This information should be of direct use to designers interested in using this new engineering material.
A Simplified Technique for the Analysis of Multi-Stepped Beams
Authors: Al-Shareef K J H , Brandon J A , Griffiths A J
Published: February 2007

The availability of software packages that enable algebraic manipulation of equations enables the reconsideration of analytical methods for design optimization which have fallen into disuse because of the difficulty of automating the analysis. Here, the analysis of multistepped beams is simplified by replacing the multi-stepped geometry by a beam of uniform cross-section. A general formula is established to define the induced forces and moments that replace the steps. This enables the singularity function method, which is usually restricted to the analysis of uniform beams, to be easily applied to determine shearing forces and bending moments, and thus simplifies the analysis.
Mechanics of Biological Materials and Structures: Nature's Lessons for the Engineer
Authors: Jeronimidis G , Atkins A G
Published: February 2007

Biological structures have evolved to fit their purpose and a discussion is given of the materials and engineering reasons for their success. The contrast is made between traditional engineering's extraction of maximum benefit from choice of materials and Nature's extraction of maximum benefit from structural shapes made of indifferent materials. The issue of integration and continuous optimization from the molecular level up to large structural components is highlighted. The relevance of such principles to engineering design is explored. Biological systems are also intelligent and an exciting possibility is that the engineering designer will be able to make use of materials and structures that are capable of preparing themselves for future events, not merely respond to immediate events. This, and ideas of integrating use with function, will require radical changes in design thought processes.
Physical and Geometrical Non-Linearities in Contact Problems of Elastic Turbine Blade Attachments
Authors: Zboinski G
Published: February 2007

The paper presents briefly the theoretical basis of linear and non-linear contact problems of linear elasticity as applied to the kinetostatic analysis of turbomachinery blade attachments. The physical and geometrical non-linearities of the problem are due to friction and unilateral constraints respectively. For three classes of contact problems finite element calculations of a real fir-tree turbine blade attachment with and without clearances within the contact surfaces are performed. The results for effective stresses of the root and disc hooks are thoroughly analysed and compared. Furthermore, the results for contact node status and nodal slips between the blade root and the disc sector are presented. The significance of the physical and geometrical non-linearities to the stress, displacement and contact states of the attachment is then discussed.
Rotordynamics Standards: New Developments and the Need for Involvement
Authors: Parkinson A G , McGuire P M
Published: February 2007

The paper reports recent developments in international standards which are particularly pertinent to manufacturers and operators of rotating machinery. In particular it discusses standards relating to balancing, especially flexible shafts, and acceptable vibration levels for rotating machinery.

In the area of balancing the report is very opportune because, following an unanimous international ballot at the Draft International Standard (DIS) stage, a new standard ISO 11342, ‘Mechanical vibration—methods and criteria for the mechanical balancing of flexible rotors’, has just been published. Nevertheless, despite publication of this new standard, ISO 11342, work is already under way on a major revision in which the classification of rotors will be completely changed.
The Case for a General Method of Kinematic Analysis of Plane Mechanisms Based on Equations of Constraint
Authors: Fogarasy A A , Smith M R
Published: February 2007

All but the simplest of single degree of freedom mechanisms have a relatively large number of component parts. To analyse the motion of such systems, therefore, one parameter is rarely sufficient. For an adequate description of the motion characteristics of all components, a number of additional coordinates are needed.

This paper introduces a clear and logical notation which facilitates the setting up of the required number of constraint equations by simple inspection of clear line diagrams of the mechanism to be analysed. These constraint equations are eminently suitable for the calculation of velocities and accelerations by direct differentiation. The resulting equations are linear in the velocities and accelerations of all component parts. A method based on this approach is presented and applied to a selection of widely different examples.
A Theoretical Analysis of Fatigue Cracking in Flexible Pavements
Authors: Collop A C , Cebon D
Published: February 2007

This paper examines theoretically the possible mechanisms of fatigue cracking in asphalt pavements using linear elastic fracture mechanics (LEFM). The effects of a non-uniform transverse contact traction between the tyre and pavement on longitudinal surface fatigue cracking are examined theoretically using a finite element (FE) pavement model. Fatigue cracking due to thermal loading is also examined using a simplified linear viscoelastic pavement model. Results indicate that the non-uniform transverse contact traction produces short surface cracks (10 mm) but does not lead to significant pavement fatigue. However, for these short surface cracks, the combined vehicle and thermal load cycles may produce conditions that are favourable for fast fracture. Fatigue cracking (both longitudinal and transverse) at the base of the asphalt layer is found to be mainly dependent on the pavement geometry and the magnitude of the normal load.
Effect of Vortices on Liquid Outflow from Vessels
Authors: Harvey R , Kubie J
Published: February 2007

This paper considers the effect of vortices on liquid outflow from open vessels. One of the simplest possible arrangements is investigated: an axisymmetric vertical cylindrical vessel with an outlet in its base. A simple spiral vortex is either introduced by supplying the liquid tangentially to the vessel and the outlet or suppressed by the installation of a vortex breaker.

A new flow regime for well-developed vortex flow is identified. In this flow regime the variation of the liquid level in the vessel with the flowrate is relatively independent of the method of supply of the liquid to the vessel, and can be correlated by a simple equation.
A Model of Whole-Life Flexible Pavement Performance
Authors: Collop A C , Cebon D
Published: February 2007

A new ‘whole-life’ pavement performance model (WLPPM), which is capable of making deterministic pavement damage predictions due to realistic traffic and environmental loading, has been developed. A vehicle simulation is used to generate dynamic tyre forces that are a function of distance along the road. These dynamic tyre forces are then combined with the appropriate pavement primary response influence functions (stress, strain and displacement) to give primary response histories at regularly spaced points along the pavement. The primary response histories are then transformed into pavement damage (fatigue and permanent deformation) using an appropriate damage model. The result is an increment of damage at each point along the pavement due to a single vehicle pass. The pavement surface profile is then updated to reflect permanent deformation damage and the layer material parameters are changed to reflect fatigue damage. The procedure is then repeated for the next vehicle pass. Particular attention is given to modelling strength variations in the pavement and dynamic tyre forces.

The model is used to investigate the relationship between ‘hot spots’ (due to peak dynamic loads), ‘weak spots’ (due to initial pavement stiffness variations) and long-term pavement damage.
The Assessment of the Rheological Characteristics of Various Polyborosiloxane/Grit Mixtures as Utilized in the Abrasive Flow Machining Process
Authors: Davies P J , Fletcher A J
Published: February 2007

Abrasive flow machining (AFM) is a non-traditional machining process used since the mid-1960s, which utilizes a mixture of polyborosiloxane and abrasive grit additions extruded across surfaces and edges and through component cavities. The machining mechanism of this process is still only partially understood due to its complex nature, and the present work undertook to investigate the relationship between the rheological characteristics of several mixtures and their associated machining parameters. This paper addresses those rheological characteristics of the various mixtures used in the present work.

Experiments were conducted using low viscosity (LV), medium viscosity (MV) and high viscosity (HV) polyborosiloxane base media, in conjunction with silicon carbide abrasive grit of 60 and 100 mesh size, the ratios of the grit to base polymer used being 0, 1 and 2. The test pieces used were mild steel dies and the equipment used to conduct the experiments was an Extrude Hone mark 7 A machine.

The results have shown that progression from low to high viscosity base medium produces a reduction in the temperature rise (for example from 32 to 10°C over 30 cycles) as well as an increase in both the average pressure drop across the die (for example from 1700 to 2674 kPa over 30 cycles) and the processing time (for example from 28 to 406 s over 30 cycles). In addition, the temperature of the medium is seen to be an important variable in the AFM process due to its effects on viscosity. Furthermore, as the usage of a medium increases the viscosity and pressure drop across the die increase.
Analysis of Measured Droplet Size Distribution of Air Deflected Diesel Spray
Authors: Aigal A K , Singal S K , Pundir B P
Published: February 2007

The droplet size distribution in diesel spray from a multi-hole nozzle deflected by cross air flow is measured using a laser diffraction technique. The spatial and temporal droplet size distributions are obtained at different transverse air velocities and ambient pressures. The effect of air density, instantaneous injection rate, etc., on droplet size is studied. Results of this investigation indicate that the droplet size is reduced and the size distribution becomes narrower at higher transverse air velocities. Using experimental data, nonlinear correlations are derived for prediction of two-dimensional spatial and temporal variations of droplet size distribution and fuel concentration in a deflected spray.
The Development of a Low Floor Citybus—Volvo B10L
Authors: McKnight J
Published: February 2007

For the 1995 Sir Henry Royce Memorial Lecture the author describes the background behind the development of the Volvo B10L low floor citybus. This includes the initial vehicle concept through the simultaneous engineering process to production start, including methods used in the product verification. Views are expressed regarding the future direction of low floor products.
A BVIF-Integrated Hybrid Bus
Authors: Moosavi-Rad H
Published: February 2007

This paper presents a band variable-inertia flywheel (BVIF) concept for the intermediate storage of recoverable energy for usage in the stop-go operation of a transit bus. A mathematical model is presented for the dynamics of the flywheel system and some numerical results are presented for an evaluation of the performance of the BVIF system integrated into the ‘real-life’ operation of a bus. A considerable fuel saving and extended brake shoe life have been demonstrated.
Monitoring of the Mixture Strength in the Cylinders of a Port-Injected Gasoline Engine During Transient Operation
Authors: Ladommatos N , Rose D
Published: February 2007

A method has been developed which allows monitoring of the air—fuel ratio within the cylinders of a running gasoline engine. The method, which uses a fast-response flame ionization detector (FID), is capable of resolving the air—fuel ratio of individual consecutive engine cycles This method was used to monitor the air—fuel ratio in a port-injected gasoline engine during fast throttle opening. The results obtained show that for a handful of engine cycles the air—fuel ratio departs from the stoichiometric Value. Using additional measurements of the air and fuel supplied to the engine, it was possible to investigate the accumulation of fuel on the inlet port walls of the engine during the throttle opening.

The results presented in this paper suggest that the departure of the air—fuel ratio from the stoichiometric value is shorter lived than that recorded by other investigators who used exhaust oxygen sensors for their tests.
Optimal Design of Conventional In-Line Fuel Injection Equipment
Authors: Kegl B
Published: February 2007

The paper describes an application of optimal design procedure employed on conventional in-line fuel injection equipment for a diesel engine. The procedure is applied to a set of design parameters concerning the design of the cam, high-pressure pump, delivery valve, snubber valve, high-pressure tube and injector respectively. The values of these design parameters are optimized simultaneously within specified maximum and minimum values in order to approach a target injection rate history.

The proposed optimal design procedure is defined as a solution process of a non-linear mathematical programming problem defined by the objective and constraint functions. The objective function measures the difference between the target and actual injection rate histories while the constraints concern the response of the system as well as several technological limitations. The form of the objective function is such that it requires special treatment similar to those employed in optimal design of dynamic multi-body systems. However, the complexity of the fuel injection equipment causes specific numerical difficulties when the ideas employed for dynamic systems are adopted. The paper describes how to modify the usual approach in order to circumvent these difficulties.

The theory is illustrated with a numerical example comparing the usual versus the modified approach.
Engine Performance Monitoring by Means of the Spark Plug
Authors: Zhao H , Collings N , Ma T
Published: February 2007

The importance of measuring ‘what is going on’ inside a spark ignition engine is well recognized. Knocking combustion cyclic variation, misfiring arid plug fouling are some of the processes to be monitored and controlled. In this work, a new system capable of monitoring these processes using the spark plug is described. The technique relies on a new design of the spark plug ionization detection circuit incorporated in the secondary winding of an ignition coil. It avoids the use of high-voltage diodes that are expensive and unreliable. It can be built into one unit with an ignition coil and directly applied to the one coil per plug system. By way of demonstration, the system's operation is reported for investigations of knock detection and engine cyclic variations in a spark ignition engine.
Detection of Automotive Catalysts Failure by Use of On-Board Diagnostics
Authors: Koltsakis G C , Stamatelos A M
Published: February 2007

Although major emission reductions from gasoline vehicles have been achieved with the help of catalytic exhaust gas after-treatment, durability of the systems involved is still difficult to guarantee with high confidence levels. On-board diagnosis (OBD) of the main emission control systems is expected to play a central role in any modern emission reduction policy. An overview of theoretical principles regarding catalytic converter operation characteristics, catalyst activity deterioration and OBD system requirements is initially presented. The most important existing approaches to catalytic converter on-board diagnosis are examined by means of presenting principles of operation, assessment methodologies and practical problems associated with each of them. The techniques examined cover dual lambda sensor, hydrocarbon and temperature measurement methods, some of which have already been applied to conform to transitional OBD regulations. It appears, however, that significant work remains to be carried out in order to develop reliable and cost-effective catalytic converter OBD technology to cover legislation requirements, especially for modern low-emitting vehicles.
Dynamics of off-Road Tracked Vehicles Equipped with Trailing Arm Suspension
Authors: Dhir A , Sankar S
Published: February 2007

A two-dimensional computer simulation model is developed for dynamic analysis of high-mobility tracked vehicles fitted with a trailing arm suspension system. The simulation model is oriented as a design tool for detailed analysis of vehicle suspension dynamics and ride quality assessment. The Lagrangian model formulation of a tracked vehicle is derived by considering a rigid terrain of an arbitrary profile and constant forward vehicle speed. The model incorporates detailed representations of a vehicle suspension system and dynamic wheel-track-terrain interactions. The wheel forces are evaluated based on an adaptive footprint formulation of a wheel/track-terrain contact patch, and the track forces are modelled based on kinematic considerations. The computer model predictions are validated against field measurements, which were gathered from an extensive field testing of an in-service armoured personnel carrier. The comparison between measured and simulated dynamic responses exhibits a fairly close correlation.
On the Distance Required to Atomize Diesel Sprays Injected from Orifice-Type Nozzles
Authors: Yule A J , Salters D G
Published: February 2007

Conductivity probe measurements, using ranges of nozzles, liquid properties and gas densities, have revealed more extensive and reliable information on the break-up process of diesel sprays than has been published to date. The spray generated from a single-hole orifice-type nozzle has an incompletely atomized break-up length which typically extends at least 100 hole diameters downstream. The physical structure of this break-up zone varies, depending on the liquid properties and both initial and boundary conditions, from that of a central liquid column, with outer drops and ligaments, to, more typically, that of a chaotic ‘wire wool’ structure of ligaments and drops. Time variations of the break-up length are found during spray pulses and concentrations of poorly atomized liquid are convected downstream in the form of coherent structures. The existence of this zone has repercussions with respect to spray-gas flow interaction, fuel vaporization and wall wetting in internal combustion engines.
Results of Investigation of an Electropneumatic Active Vibration Control System for a Driver's Seat
Authors: Stein G J
Published: February 2007

The aim of this paper is to present some results of a study of an electropneumatic active vibration control system (AVCS) utilizing a pneumatic spring and a proportional electropneumatic transducer. It is treated as a one degree of freedom linear oscillatory system, working predominantly in the vertical direction. A discussion of various AVCS models and respective linear control laws is followed by a short description of the full-scale dummy system aimed for the driver's seats of heavy earth-moving machines and trucks. Some experimental results are presented too.
Modelling the Dynamic Behaviour of A Motorcycle Damper
Authors: Audenino A L , Belingardi G
Published: February 2007

Within the context of vehicle suspension component characterization, that of shock absorbers is one of the more difficult to achieve, yet it is a very critical factor in the prediction of vehicle dynamic behaviour. Strongly non-linear output force functions are always linked to a frequency-dependent behaviour. Using the internal fluid-dynamic phenomenon with respect to a motorcycle shock absorber, different physical models of increasing complexity are presented: using these models it is possible to evaluate the importance of different factors, for example oil compressibility or oil inertia. Comparisons with experimental data confirm the validity of these models
Optical Research Engines—Tools in Gasoline Engine Development?
Authors: Winklhofer Dr E , Fuchs Dr H , Fraidl Dr G K
Published: February 2007

The paper describes the design of a single cylinder base engine which provides optical access to the combustion chamber via glass cylinders and a piston with a glass crown. The application of this engine to the visual analysis of gasoline mixture formation and combustion is demonstrated with examples given for two- and four-valve cylinder heads.

The optical methods used in this study comprise laser-induced fluorescence (LIF) to image the unburned mixture within the laser light sheet illuminating a plane of the combustion chamber and flame photography to visualize flame propagation. Simultaneous recording of engine thermodynamic data allows the comparison of conventional engine diagnostics with the results gained from the optical techniques.