bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement and Modelling of Ignition System Energy and its Effect on Engine Performance
Authors: Stone C R , Steele A B 
Published: February 2007

This study investigates the effect of ignition parameters on the cyclic dispersion and the specific fuel consumption of a carburetted single-cylinder engine. Ignition energy measurements were made on the low- and high-voltage sides of the ignition coil, and the performance was predicted satisfactorily by a simple model with passive elements. The spark energy was varied by changing the spark plug gap and the coil-on-time. The spark energy was measured in a special calorimeter: the aim was to find a correlation between engine performance and the spark energy measured by the calorimeter. The tests were conducted at part load and low speed with a weak mixture, as these conditions are known to give high levels of cyclic dispersion. The spark calorimeter showed a higher spark plug conversion efficiency for spark plugs with large gaps. However, the spark plug gap was found to be a more significant determinant of engine performance than the spark energy measured by the calorimeter. The experimental results are preceded by a review of ignition phenomena and their influence on combustion.
Buckling of Externally Pressurized Composite Torispherical Domes
Authors: Galletly G D , Muc A 
Published: February 2007

The results of external pressure buckling tests on 0.25 m diameter woven composite (mainly CFRP) domes are given in the paper and they are compared with the predictions of the shell buckling program BOSOR 4. The agreement between theory and experiment was satisfactory. The tests also show that the buckling strength of CFRP torispheres is good. They could replace steel torispheres and would be considerably lighter. The buckling pressures of the woven composite domes are a function of the Young modulus E but the relation is not a simple linear one (the in-plane shear modulus G12 also needs to be taken into account). Results of some tests on CFRP and GFRP domes lend support to this statement. The provisions of BS 4994, when applied to these domes, predict that buckling is the controlling failure mode. While this is correct, the buckling pressures predicted by BS 4994 seem rather low. The effect of dome thickness on the buckling pressures was expected to vary as (t/R)2. This was confirmed herein, to a limited extent, by a few tests on shallow CFRP domes.
Inter-ring Buckling of Welded Ring-Stiffened Cylindrical Shells Subjected to External Pressure
Authors: Galletly G D , James S 
Published: February 2007

Test results are given in the paper for six 0.6 m diameter welded steel cylinders, stiffened by external T-rings, which were subjected to external pressure. The radius-thickness ratio of the cylinders varied from 185 to 300 and the ratio of the length of the central bay of the cylinders to the radius varied from 0.28 to 0.60. In the assessment of the test results, three design codes were employed, viz. BS 5500, DASt 013 and ASME Code Case N-284. The main aims of the tests were (a) to determine if the external pressure section of BS 5500 was too conservative in the ‘elastic’ range and (b) to ascertain whether the other two codes always gave safe predictions of buckling pressures. On the basis of the tests discussed herein, it is concluded that, for externally stiffened cylinders, the reduction factor, α, in BS 5500 could be increased from 0.5 to 0.6 in the ‘elastic’ buckling region. Doing this would have commercial benefits but, before it is done, more tests need to be carried out in order to establish the repeatability of the present results. With regard to the DASt 013 code and ASME Code Case N-284, both of them predicted buckling pressures that were too high in several cases. These codes should be amended, particularly for cylinders which have geometric ratios similar to those tested herein. In connection with this point, the authors have been informed recently that DASt 013 will be replaced by DIN 18800, Part 4, some time in 1989. The buckling predictions of this new code, when applied to the six ring-stiffened models discussed herein, appear to be satisfactory. Some recent German tests on short unstiffened cylinders are also reviewed and discussed from the viewpoints of the BS 5500, DASt 013 and ASME N-284 codes.
Resilient Railpads: Their Dynamic Behaviour in the Laboratory and on Track
Authors: Grassie S L 
Published: February 2007

Resilient railpads in a variety of materials and with different surface profiling have been tested in the laboratory and in track. A laboratory impact test based on that initially developed at the Battelle Columbus Laboratories provides a reliable ranking of the extent to which railpads attenuate dynamic strain in concrete sleepers in track. The test is also a good indication of the average attenuation provided by a pad in track. If dynamic loads in track are particularly severe the fractional attenuation provided by a pad is greater than that indicated by the laboratory impact test. Laboratory resonance apparatus, in which the pad is the principal resilient element in a simple dynamic system, has been made to find the railpad's effective dynamic stiffness. There is good correlation between the stiffness measured in track and that measured in this apparatus. A pad's dynamic stiffness is consistently at least as great as its tangent stiffness found from the static load/deflection curve. The load/deflection behaviour of a pad in track can be found from measurements in an assembly of rail and sleeper in the laboratory.
Supply-Side Harmonics in d.c. Supplied Drives: An Approach to Their Specification and Control
Authors: Goodman C J , Taufiq J A 
Published: February 2007

The use of power electronic switching controllers for all types of traction drives can lead to harmonic currents on the supply side. These currents, by conductive or mutual coupling, can cause interference in signalling and telecommunications circuits. After reviewing these basic considerations, this paper outlines the harmonic spectra of d.c.-supplied chopper and inverter drives. In the case of chopper controllers, choosing a frequency unrelated to any signalling frequency combined with the attenuation provided by the input filter is usually sufficient to avoid dangerous interference. For inverter drives, the situation is more complex due to the intrinsic sweep frequency nature of the drive. However, special modulation strategies can be used for the inverter which eliminates, or at least reduces to a safe level, any particular frequency which may interfere with signalling equipment. A method for generating these optimized pulse-width modulation schemes using fast on-board microprocessors is briefly described.
Procurement of Rolling Stock on the Hong Kong Mass Transit Railway
Authors: Donald W R , Gretton J R , Turner T D 
Published: February 2007

This paper gives an account of the procurement of the electric multiple unit trains which have been manufactured and brought into service on the Mass Transit Railway in Hong Kong. The paper outlines the Corporation's project management and control systems used on rolling stock contracts that have been let within the three major projects constructed over the period 1975–86; the modified initial system, Tsuen Wan extension and the Island Line, and examines the development of rolling stock equipment and procurement methods within these projects and in further contracts which are still to be completed. Brief details of the railway system and parameters for design of the rolling stock are given and the paper reviews the planning, programming, forms of contract documents, tender procedures, financing methods and contract management techniques used by he Corporation in the rolling stock contracts.
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.
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.
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.
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.
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.
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.
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 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.
Analysis of Active and Semi-Active Vehicle Suspensions Fitted with a Pneumatic Self-Energizing Levelling Device
Authors: Hall B B , Tang J S 
Published: February 2007

A pneumatic self-energizing self-levelling (SESL) device is proposed in schematic form and a theoretical analysis of it is carried out. The unit allows the design suspension working space to be maintained once steady state operating conditions have been reached. Conventional passive, semi-active and fully active suspensions are all disadvantaged by variable vehicle payloads. An investigation is carried out to determine what advantages are to be gained by combining the SESL unit with each of these types of suspension. Computing simulations have been used to show that for large payloads it has the ability to: (a) improve the performance of a conventional passive suspension, (b) reduce the power requirements of a fully active system and (c) maintain the performance of a semi-active system close to that of a fully active system for a wide range of payloads. It is concluded that the SESL device has most to offer when it is used in conjunction with a semi-active system containing a variable-rate switchable damper.
Buckling of Slightly Flattened Domed Ends Reinforced Locally with Fibre-Reinforced Plastic
Authors: Galletly G D , Moreton D N , Muc A 
Published: February 2007

This paper discusses external pressure tests carried out on machined steel torispherical domes, such as those used as end closures on cylinders. There were small axisymmetric regions at the poles of the shells, in which the local radius was greater than the nominal one (that is the domes had increased-radius geometric imperfections, or ‘flat’ spots, in them). The ‘flat’ areas were covered with CFRP (carbon fibre reinforced plastic) and one aim of the tests was to see if the buckling strength of the reinforced imperfect domes could equal that of a similar, unreinforced, perfect dome. Two sizes of polar flattening were investigated. The agreement between the experimental failure pressures and the theoretical predictions of the BOSOR 5 shell buckling program was good. The tests showed that the flattened dome's buckling resistance could indeed be restored (so that it equalled that of the perfect dome) by covering the flattened area (and its environs) with CFRP. It was also shown that, by applying a somewhat thicker composite layer to the localized flat region, it was possible to achieve the same buckling resistance with glass fibre reinforced plastic (GFRP) as with CFRP. The former material is, of course, much cheaper. Perfect and imperfect (that is with local flattened regions) steel domes were also tested under external pressure. The test results and the BOSOR 5 predictions were in good agreement for these models.
Mechanics Analysis of the Die Drawing Process for Producing Oriented Polyethylene Terephthalate (PET) Tube
Authors: Craggs G 
Published: February 2007

An analysis is presented of the die drawing process used to produce transparent polyethylene terephthalate (PET) tube having a high degree of molecular orientation and consequently superior mechanical properties to tube in the isotropic state. The stress in an element of material being drawn is determined from equilibrium considerations and by using the Tresca yield criterion. Flow stress values used in the analysis allow for strain rate effects during drawing and were obtained from uniaxial stress-strain data and applied to the problem using equivalent stress-strain concepts. Results are presented of die drawing tests carried out on a large-scale die drawing facility on PET tube at 100°C. Predicted drawing loads for an assumed value of friction coefficient of 0.2 compared well with experimental values for billet velocities greater than 7 mm/min. Draw ratios of up to 3.5 were achieved in tests when there was evidence of crystallization during the free drawing of the material downstream of the die exit.
Deflection Characteristics of Tubular Diaphragm Separators Used in Diaphragm Separator Pumps
Authors: Brett P N , Longmore D K 
Published: February 2007

A simple method is described for computing the volumetric displacement of a tubular diaphragm on a mandrel, as used in a diaphragm separator pump, for any given pressure differential across it. The computer model involves a plane strain analysis and regards the diaphragm as a curved beam in bending, shear and tension. Comparison with experiment has shown the model to give accurate predictions of diaphragm behaviour. The design of a diaphragm is discussed, making use of the computer model. Attention is given to the choice of wall thickness, elastic modulus and mandrel support and the manner in which they affect diaphragm life, the volumetric efficiency and operation of the pump.