bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Investigation into Distribution Parameters of Steam Turbine Blade and Wheel Vibration Measurements
Authors: Farid M U 
Published: February 2007

This investigation was carried out to find a concise and meaningful way of describing the steam turbine blade and wheel vibration measurements which would enable predictions from ‘experimental’ to ‘production’ wheels to be made with known level of confidence. A large volume of vibration measurements from many years of testing was available. For the purpose of this study it was decided to concentrate the analysis on stage six of low-pressure turbine wheels. Two types of wheels, similar in every respect except root fixation, were used. The method of obtaining and interpreting static and dynamic blade and wheel vibration frequency measurements is described. Measurements from the wheels selected for study were analysed by appropriate statistical techniques to test assumptions and hypotheses derived from long-standing experience of empirical vibration tests. It was found that statistical analysis yields results in line with engineering expectations. In specific instances relating to the use of ‘experimental’ wheels in predicting the performance of ‘production’ wheels the statistical analysis not only confirmed existing practice, but pointed towards a more precise foundation of the procedure of estimating dynamic frequencies for production wheels. The suitability of the use of statistical techniques for analysis of problems of this kind is discussed.
The 250 kW and 3 MW Wind Turbines on Burgar Hill, Orkney
Authors: Lindley D 
Published: February 2007

The Wind Energy Group has designed and manufactured a 20 m diameter wind turbine generator, rated at 250 kW. Following an extensive period of tests, it was erected on Orkney in July 1983. It rotated for the first time in late July and was synchronized with the grid in August 1983. The commissioning tests have been completed and are to be followed by not less than twelve months of performance monitoring. This paper gives details of the machine design and specification, details of sensors and monitoring system and early results of the commissioning phase. As part of the same programme, a 60 m diameter turbine rated at 3 MW has been designed for installation in 1985 at the same location. Details are given in this paper of the design and specification of this machine.
Health and Safety Legislation and Engineers
Authors: Cartwright P A , Wearne S H 
Published: February 2007

Through legislation and other social forces the UK and other industrial societies appear to be expecting increasingly higher standards of health and safety to result from engineers' work. Engineers therefore need to know the controls of hazards required by law. They also have to consider their professional duty to anticipate new hazards. This paper gives the results of questioning small samples of UK engineers to assess their problems and needs under health and safety legislation. It includes a specification for engineering education and a description of the teaching in one undergraduate degree.
Computer Controlled Pneumatic Servo Drives
Authors: Weston R H , Moore P R , Thatcher T W , Morgan G 
Published: February 2007

This paper describes how microprocessor-based controls can be used to produce low cost pneumatic servo drives which could find wide application in manufacturing industries. The approach incorporates digital compensation for system non-linearities so that, when positioning loads in a ‘point to point’ mode, it is possible to achieve a significant improvement in both the static and dynamic performance of the drive. For the compensation algorithms implemented a theoretical foundation is presented based on a linearized model of pneumatic drives. The paper also describes how microprocessor-based hardware and software have been constructed to evaluate performance criteria. This test facility has allowed the software implementation of the compensation algorithms to be refined so that satisfactory performance can be achieved with both translational and rotational drives utilizing various forms of transmission. The test facility has also allowed various control system elements to be evaluated so that pneumatic drives suitable for industrial application, can be specified.
Oscillatory Instabilities Generated in a Double-Pin and Disc Undamped System: A Mechanism of Disc-cbrake Squeal
Authors: Earles S W E , Badi M N M 
Published: February 2007

A dynamic analysis is presented of a double-pin and disc system, which is undamped and has linear characteristics. A self-induced oscillatory motion is generated which can become unstable for certain combinations of the system's parameters. Unstable motion requires a set of inequality equations to be satisfied, and a necessary, but not sufficient condition is that one or both of the pins shall have a negative (digging-in) angle of orientation to the disc surface within the range 0 < θ < tan−1 μ. Sufficient conditions for unstable motion are dependent on the magnitudes of the system parameters and may be obtained by giving unequal values to corresponding parameters on the two-pin systems. Distinct changes from a ‘quiet’ to a ‘noisy’ state are observed on an experimental system; the ‘noisy’ state regions having a good correlation with the instability regions shown theoretically. It is concluded that a ‘kinematic constraint’ or ‘geometrically induced’ class of instability exists theoretically which essentially describes the mechanism of squeal noise generation in disc-brakes.
Challenge, Change and Commitment
Authors: Waller J A 
Published: February 2007

The author illustrates the challenges which he has faced in many changes of function and responsibilities. In doing so, he relates them in a way which highlights many fundamental operating and engineering truths. He hopes they will be recognized by younger Engineers making their way in engineering, and adopted by them as part of their engineering education. Finally he lends support to the President's initiative to the Institution and its members to play a leading part in the turn round of the engineering industry. To this end he challenges Automobile Division members to commit themselves to the Institution and to adopt a theme for personal action during his year in office: ‘Resolve your Problems’
London Transport'S 1983 Tube Stock
Authors: Ware D K 
Published: February 2007

The 1983 tube stock has been designed for use on the Jubilee Line and should enter service there in the Spring of 1984. The line itself has suffered many changes—in both direction and identity, metamorphosing from the original Fleet Line concept of 1971 through the River Line to the full Jubilee Line proposal of 1977. It has now been truncated to its Stage 1 terminus of Charing Cross and the intention to continue to Woolwich has been abandoned. The design of the rolling stock could hardly avoid changes of a comparable nature and the paper describes some of these. The trains have finally emerged as fairly conventional vehicles based on the Piccadilly Line 1973 tube stock. Many changes both major and minor have however been incorporated and the design may well be the final and most developed version of the classic London tube car with steel underframe.
The Dissipation of Frictional Energy from the Interface of an Annular Disc Brake
Authors: Day A J , Newcomb T P 
Published: February 2007

The performance of resin bonded composite friction materials in a particular brake design is strongly dependent upon the dissipation of frictional heat from the interface. This energy transformation has been studied using finite element techniques for a simulation of the braking friction process in an annular disc brake, which combines both brake performance and brake temperature analysis and avoids many of the assumptions necessary in conventional analyses. Negligible amounts of energy interchange, compared with the total kinetic energy dissipated, arise from chemical reactions within the friction material, but the formation of surface layers and interfacial wear products do have a significant effect upon heat transfer from the interface. Calculated temperature distributions over individual brake applications indicate that interface contact resistance leads to different temperatures at the surfaces of disc and lining so that heat partition between the two mating bodies cannot realistically be assumed constant under braking conditions. The distribution of frictional heat generation over the interface is dependent upon interface pressure distribution and is therefore also affected by material wear and thermal expansion. These effects are incorporated in the analysis, and calculated temperature, interface contact and pressure, and wear distributions are compared with observed and measured experimental results from an annular brake rig.
The Thermal–Hydraulic Design of Main Feed Water Pump Suction Systems for Large Thermal Power Plant
Authors: Dartnell Lawrence 
Published: February 2007

British domestic design practice is described for boiler feed pump suction systems associated with high level deaerator/feed water tanks in large modern power plant. The objective of thermal–hydraulic design is the provision of adequate pressure to boiler feed water pump suctions under all transient and steady state conditions to ensure continuity of water flow and reliable pump operation. Methods are available for the determination of pressure decay in feed tanks during load transients, but the successful application of mathematical relationships between pressure decay and pressure rise in suction pipework depends on the correct identification of operational circumstances. Progress in recent years has been on the identification of circumstances which produce governing conditions and has taken design practice beyond the stage established by early workers. Developed practice has been successfully applied by the Central Electricity Generating Board and its main plant contractors to forty-nine 500 MW units in coal- and oil-fired stations and to twenty-three 660 MW units in coal, oil and advanced gas-cooled reactor stations, which at 39 680 MW, constitutes the major proportion of plant in England and Wales. Aspects of plant behaviour and operation crucial to successful system design are featured. Recommendations are made for plant layout, pipework routing, tank outlet and pipework sizing, net positive suction head (NPSH) determination etc.
An Assessment of the Impact Performance of Bonded Joints for Use in High Energy Absorbing Structures
Authors: Harris J A , Adams R D 
Published: February 2007

Using an instrumented impact test, the strength and energy absorption of bonded single lap joints have been measured for single lap joints with four epoxy adhesives and three aluminium alloy adherends. Compared with the static values, joint strength is not significantly affected by the high loading rates. Energy absorption is large when joint strength is sufficient for plastic deformation to occur in the adherends prior to failure, which is only the case for certain adherend/adhesive combinations. Spot welded joints are shown to be inferior in performance in the tests. The effect of loading rate on bonded joint strength has been analysed using a non-linear finite element method, from which predictions of joint strength in keeping with the experimental results have been obtained. Crush tests carried out on open-ended cylinders have been used to simulate the impact behaviour of an energy absorbing structure. Similar performance was observed for cylinders with either bonded or spot welded longitudinal seams, although the large deformations in the crumple zones led to some debonding and weld fracture.
An Evaluation of Spline Functions for use in Cam Design
Authors: MacCarthy B L , Burns N D 
Published: February 2007

This paper shows how spline functions can be employed for kinematic motion specification in cam design. The polynomial spline is introduced as a special case of a continuous piecewise function. Cubic and quintic splines are derived and their properties are discussed in the cam design context. It is shown how standard cam laws can be approximated extremely accurately with a small number of points and appropriate boundary conditions. The modified sinusoidal acceleration cam law is used as an example. The application of quintic splines to non-standard and special motions is discussed. The algebraic and B-spline representations of spline functions are compared. The former is considered preferable in this context and a list of useful algorithms is given. The real power of the spline function, in particular the algebraic quintic spline, is its simplicity, ease of computation and adaptability to non-standard design problems. The use of parametrized, deficient and exponential splines is proposed for specific applications.
Interactive Buckling Tests on Cylindrical Shells Subjected to Axial Compression and External Pressure—A Comparison of Experiment, Theory and Various Codes
Authors: Galletly G D , Pemsing K 
Published: February 2007

The buckling of welded steel cylindrical shells under the combined action of external pressure and axial compressive loads is of considerable interest to the offshore oil and nuclear industries. However, test results on this subject are scarce and some design rules which have been proposed recently have not been validated experimentally, especially in the plastic buckling region. In order to check these rules, and suggest others, interactive buckling tests were conducted at Liverpool University on cylindrical shells having R/t ≍ 100. One series of tests consisted of 19 machined and stress-relieved steel models having L/R ratios of 0.33, 0.74 and 1.45. The results obtained on these near-perfect machined models were compared with theoretical predictions of the behaviour of perfect cylindrical shells and the agreement between the two was good The other series consisted of 21 welded steel models and had geometric ratios which were similar to the machined ones. The linear interaction equation Sp + Sx = 1 was used to predict the failure loads of these welded steel models and the predictions were safe in all cases. However, for some combined loading cases the linear equation was rather conservative and, in consequence, some non-linear interaction equations were investigated. These seem promising for design purposes. Irrespective of whether a linear or a non-linear equation is chosen for design, more tests will be needed to establish the scatter bands of the interactive buckling curves for various values of R/t. Some tests were also carried out on (a) the effect of the loading path on the failure loads and (b) models with localized dents. Other topics discussed in the paper are: the effects of residual stresses and initial geometric imperfections, the general procedure adopted by Codes to predict buckling loads and some discrepancies between the predictions of various Codes.
A Three-Dimensional Finite Element Analysis of the Cold Forging of a Model Aluminium Connecting Rod
Authors: Pillinger I , Hartley P , Sturgess C E N , Rowe G W 
Published: February 2007

A fully three-dimensional elastic-plastic finite element method is used to simulate metal flow during the most complex stage of the cold forging of a model of an aluminium connecting rod. The results of the computer simulation are compared with the forging of strain-hardening aluminium billets using graphite lubrication. The analysis predicts deformation patterns and hardness distributions which have been checked by selected experiments. The experimental results show inhomogeneous deformation in various parts of the forging and noticeable variations in the formation of flash around its periphery, features which are also found in the analyses. The elastic-plastic finite element technique can thus satisfactorily be applied to three-dimensional forgings of strain-hardening material. The work described here represents one part of a continuing research programme to develop computer simulation techniques for the modelling of complex cold, warm or hot industrial forgings.
Steel Plates for Pressure Vessels in Sour Environment Applications
Authors: Terasaki F , Ohtani H , Ikeda A , Nakanishi M 
Published: February 2007

It is well known that wet hydrogen sulphide (H2S) can cause embrittlement of steels, hydrogen induced cracking (HIC) and sulphide stress corrosion cracking (SSCC). Several fractures of pipelines handling sour crude oil or gas led to vigorous researches on these problems. As similar failures have also been experienced in petroleum refinery equipment, degradation of steel by hydrogen sulphide is now recognized as a serious environmental problem. The paper considers the mechanism and factors involved in HIC. This type of cracking occurs mainly in the parent steels. The susceptibility of steels to cracking is influenced strongly by inhomogeneities such as the shape and distribution of non-metallic inclusions, and segregation of alloying elements. These have a significant effect on HIC because they modify the microstructures in the segregated regions. With reference to environmental factors, these mainly concern the influence of H2S partial pressures, pH of the solutions and other phenomena relevant to the absorption of hydrogen by the steel. SSCC poses problems in weld zones. It can occur especially in heat affected zones (HAZ) with high hardnesses. Such cracking can be prevented by the control of hardness by a suitable selection of the chemical composition of the steel and the welding conditions. Nevertheless, countermeasures similar to those described for the prevention of HIC are necessary to prevent SSCC in HAZ even with relatively low hardness. Research on factors influencing HIC and SSCC has resulted in the development of steels which are highly resistant to wet H2S cracking. These steels have been supplied in plate form for pressure vessels. Experience has confirmed the good performance of welded constructions in aggressive service environments.
An Assessment of Primary System Stresses on the Creep Behaviour of High Temperature Steam Piping Systems
Authors: Carmichael G D T 
Published: February 2007

The effects of creep on the primary system loadings sustained by high temperature steam piping layouts are ignored in design. A detailed evaluation of the consequences of this omission is presented from both the theoretical and practical viewpoints. Piping analyses show that if systems are not supported correctly this can give rise to enhanced primary stresses. In these circumstances if the creep strength of any part of weldments is significantly less than the average rupture strength of the parent material circumferential cracking may occur in the design lifetime. A feature of the results obtained from creep analyses is that over-stressed systems tend to sink with lime. It is proposed that this characteristic can be used to help decide which piping systems should have their welds examined.
Review of Some of the Major Engineering Developments in the High-Pressure Polyethylene Process 1933–1983
Authors: Crossland B , Bett K E , Ford Hugh , Gardner A K 
Published: February 2007

F. A. Freeth provided the impetus for the research within the Alkali Division of Imperial Chemical Industries which led to the discovery of polyethylene by R. O. Gibson and E. W. Fawcett in March 1933. The importance of engineering in the development of the research equipment was recognized from the beginning by the appointment of Dr A. M. J. F. Michels as consultant on high-pressure techniques and apparatus, and by the later appointment of W. R. D. Manning as the research engineer in the team. They were, with others, responsible for the engineering development of the first chemical plant to operate continuously at pressures associated with those generated in large guns. The paper, which is based on one presented at the Golden Jubilee Conference ‘Polyethylenes 1933–1983’, * reviews the engineering developments of some of the more important components of polyethylene plants during the first fifty years. Commercial confidentiality and lack of space prohibits a discussion of some aspects of design.
Design and Technology in Schools—Its Potential for the Engineering Profession
Authors: Pace S 
Published: February 2007

The organization of schools and the curriculum have undergone major changes in the last two decades. These changes represent an opportunity for the engineering profession to promote the development of engineering qualities, within the spectrum of the broad-based, design education now becoming widely accepted as an essential ingredient in the education of all children. A new subject has evolved, known as design and technology, with its own distinctive characteristics. These are described, in relation to the potential of the subject as a high status, ‘A’ level, suitable for prospective engineers. The increasing demand for art-based, design and electronics courses at university, in contrast to the declining interest in the mechanical, is seen as a direct consequence of the successful promotion of these activities in the schools. Adequately trained and motivated teachers are identified as the key resource, and a suitable training programme to enable teachers to promote mechanical activities in schools is outlined. Ways in which the Institution of Mechanical Engineers could invest in the educational process, to secure a thriving enthusiasm for its own distinctive message, are proposed. Without these fundamentally new initiatives from within schools themselves, it is suggested that the declining interest in mechanical engineering at university, will lead inevitably to an erosion of entrance standards and of the hard-won status of the profession.
An Efficient Method for Compensating Truncated Higher Modes in Structural Dynamics Modification
Authors: Chung K R , Lee C W 
Published: February 2007

An efficient method for compensating the effects of the truncated higher modes in structural dynamics modification (SDM) is developed to predict the accurate modal parameters of locally modified structures. The effects of the truncated higher modes are represented by a fictitious, effective mode residing beyond the frequency range of interest. The modal parameters are then easily obtained by the iterative single degree-of-freedom curve-fitting technique developed for lightly damped systems. A numerical example demonstrates the effectiveness of the improved SDM technique.
Some Effects of Electrolyte Flow in the Electroforming of Iron Foil
Authors: McGeough J A , Thomson J R 
Published: February 2007

Iron foil of approximate thickness 0.05 mm has been electroformed from an electrolyte solution, composed mainly of ferrous chloride and flowing at Reynolds numbers ranging from 1620 to 19 400. Current densities between 15 and 45 A/dm2 have been used. At low Reynolds numbers, the current efficiency for metal deposition is limited by inadequate mass transfer. As the Reynolds number is increased, the current efficiency rises to a maximum, after which the efficiency is again reduced due to excessive occurrence of a reaction involving the reduction of ferrous hydroxide to iron. The Young modulus of the material along the direction of electrolyte flow is less than the recognized value for polycrystalline iron and steel. This is because of the crystal orientation and internal stresses of the electrodeposited metal. Electrolyte flow induces hydrogen embrittlement of the foil. This condition is found to exert a greater influence than grain size on tensile strength, ductility and proof stress. Its effects can be alleviated by stress relief. The hardness is unaffected by hydrogen embrittlement, but is increased at higher Reynolds numbers, due to the formation of smaller grains. Direct heating of the cathode reduces material hardness without affecting tensile properties. The introduction of electrolyte flow raises the rate of electroforming of iron only by about 50 per cent when compared with that obtained from an unstirred electrolyte. This surprisingly small effect of flow is attributed to the slowness of the chemical reactions which have more control over the rate of deposition of iron than the rate of mass transfer.