bluuebunny/crossref_metadata_2025 huggingface dataset:
Paper 22: Metal Surfaces in Contact under Normal Forces: Some Dynamic Stiffness and Damping Characteristics
Authors: Andrew C. , Cockburn J. A. , Waring A. E.
Published: June 2010

This paper describes an experimental investigation into the dynamic stiffness characteristics of flat joints subjected to an alternating force superimposed on a steady pre-load. The joints consist of the interfaces between mild-steel discs arranged in a column, in sets with surfaces either turned or lapped together. The influences of pre-load and of alternating force frequency were investigated for both dry and oiled joints, for different values of surface finish, apparent joint area and oil viscosity. The ranges of the conditions considered are compatible with those existing in typical machine tool structures.

It was found that the dynamic stiffness of dry joints is independent of frequency and no energy dissipation is measurable. The stiffness is primarily a function of pre-load and surface finish, with apparent joint area becoming important only for very good surface finishes.

If oil is introduced into the joint interface, a quadrature stiffness component arises and is accompanied by an increase in the ‘in-phase’ stiffness component. The magnitudes of the oil film stiffness components decrease sharply with an increase in the effective oil film thickness, which is governed primarily by the surface roughness. They increase with oil viscosity, the apparent joint area and the frequency of vibration, and represent a potentially valuable source of vibration damping in engineering structures.
Paper 42: Preliminary Study of the Influence of Stress and Deformation in the Substrate on Junction Growth and Friction
Authors: Fogg B.
Published: June 2010

The change in surface texture and the associated increase in ‘real’ area of contact at the surface in contact with the punch during stretch forming is very much greater than that predicted by Tabor's theory. It was suggested initially that this large change could be due to the effect of the biaxial tensile stress in the bulk material.

Subsequent tests on model asperities show that the pressure to cause yielding of the asperities is reduced when tensile stresses are present in the bulk material resulting in a larger ‘real’ area of contact for a given normal load. However, an even greater increase in contact area is produced if the bulk material is allowed to deform plastically during the application of a constant normal load. Other stress states were examined on a basis of indentation testing.

It is suggested that the greatly reduced apparent yield pressure of the asperities gives rise to high friction coefficient over the punch nose. Application of Tabor's theory, together with the already large initial real area of contact, seems to account for the observed large junction growth.
Paper 40: Measurement and Control of the Residual Stress Produced by Grinding Operations
Authors: Loxham J. , Purcell J.
Published: June 2010

The grinding process is surveyed and a technique is described which enables the efficiency of the grinding wheel, coolant, and machine tool system to be determined.

The analysis is made in terms of the maximum possible depth of cut that can be taken by the individual grits of the grinding wheel and the volume of material removed from the workpiece at this loading per unit volume of grinding wheel lost.

Suggestions are made for the practical application of the technique to minimize the residual stress which is produced by the grinding operation. The results which have been achieved are shown in graphical form, and suggestions are made for the full explanation of the technique.
Paper 10: Surface Metrology in Production Engineering Research
Authors: Crabtree J. J.
Published: June 2010

Typical industrial requirements regarding surface finish, appearance, and limits and fits for turned and cylindrically ground surfaces will be indicated from the results of a recent survey.

The results obtained during friction and wear tests on significantly sized surfaces (3 in square) will be described, with an indication of the problems associated with the adequate description of the topography of such surfaces.

The paper will also include observations on the types of surface finish now being produced during milling and reaming operations, noting the tendency to produce profiles having wavelengths which are larger than can be readily assessed using the majority of currently available workshop surface measuring instruments, and the problems associated with the evaluation of surfaces produced by other production processes, e.g. electrochemical machining, extrusion, etc.
Paper 14: Trends and Actual State of Polish Scientific Research Work in the Field of Surface Metrology
Authors: Sadowski A.
Published: June 2010

In this paper the author presents the historical development of Polish scientific research work in the field of surface metrology and especially the recent work of the following Research Centres:

Cracow: working in the field of methods and accuracy of surface roughness measurements, and particularly an investigation to determine the optimal sampling length, interdependence of Ra and Rz values after machining, indication accuracy of surface analyser, and the so-called ‘purposeful accuracy’ of measurements resulting from the heterogeneity of roughness.

Wroclaw: working in the field of accuracy of interference roughness measurements and construction of micro-interferometers.

Warsaw: working in the field of surface topography and its bearing properties under variable loads.
Paper 16: High-Precision Optical Profilometer for the Study of Micro-Geometrical Surface Defects
Authors: Dupuy Mlle O.
Published: June 2010

The principle of a high-precision optical profilometer for the examination of micro-geometrical surface defects without material contact between the sensor and the surface is explained and the prototype is described.
Paper 12: Improved Type of Wavefilter for Use in Surface-Finish Measurement
Authors: Whitehouse D. J.
Published: June 2010

This paper is concerned with the use of phase-corrected filters in surface-texture measurement. It is divided into two parts; Part 1 is devoted to the requirements of surface-texture measurement, and Part 2 is concerned with the relevant theory.
Paper 30: Review of Surface Texture Measurement and the Associated Metrological Problems
Authors: Green E.
Published: June 2010

A brief review is presented of the physical phenomena (optical, capacitance, conductance, absorption, pneumatic, and hydraulic) which have been utilized in the various types of instruments developed to express, by means of a single index, the relative roughness of different specimens. The readings taken with such instruments are normally functions of the three-dimensional characteristics of the surface under test but, since they are of an empirical nature, there is little or no correlation between measurements made with the different types of instruments.

Instruments measuring in two dimensions and recording in absolute units of length have been universally accepted. The most popular instrument is the stylus tracer type with electronic amplification of the stylus movement. The output of these devices is dependent on factors that have been standardized by the manufacturers (electronic circuitry, the form of stylus, etc.) and other elements, the characteristics of which are not uniform for all instruments (stylus support and mounting, etc.). Reference is made to the basic datum to which the readings of tracer instruments refer, the envelope line and the centre line, and the different parameters currently advocated as presenting an adequate means of describing and forming a quantitative assessment of the surface under test. The use of digital computer techniques for eliminating the many analogue devices necessary for the evaluation of the different parameters is explained.
Paper 38: Functional Assessment of Surface Roughness
Authors: Rubert M. P.
Published: June 2010

Surface roughness is defined according to geometrical parameters and is measured mainly with instruments evaluating the depths of the irregularities or other geometrical properties such as the number of peaks per unit length or the percentage bearing area at various levels.

This paper deals with the assessment of surface roughness by non-geometrical means based on functional aspects of ‘roughness’.

The study is therefore concerned with ( a) the evaluation of surface roughness by means of tactile comparison, and ( b) an instrument simulating the action of tactile comparison or the finger-nail test.
Paper 18: Graphical Method for Statistical Assessment of Surface Roughness Comparison Specimens
Authors: Eberle O. A.
Published: June 2010

To judge the quality of surface roughness specimens two criteria are particularly important: the deviation of the mean value from the nominal value, and the scatter within the specimens. These criteria may be read very easily, and without any mathematical expedients, from graphs on probability paper. The practical use of probability paper is explained.

From the evaluation of the results it is seen that the behaviour of certain instruments is such that the influence of instrument cut-off is contradictory to the theory and the opposite of the behaviour of other instruments. An attempt is made to explain this phenomenon, and an extension to the relevant standards is proposed which would ensure that all instruments conforming to the same standard would also yield the same results.

Finally, possible methods are mentioned which would enable instruments to be checked in these respects, in order to ascertain whether they possess the required characteristics.
Paper 33: Influence of Sample Size and the Relationships between the Common Surface Texture Parameters
Authors: Sharman H. B.
Published: June 2010

The textures of three ground surfaces were examined in terms of the common surface texture parameters. The r.m.s. values, calculated from the data-logged Y-ordinate heights of the profile recordings, were used to predict the values of the various parameters. The influence of sample size on the numerical values of these parameters is discussed.
Paper 11: Mathematical Expression of Surface-Finish Characteristics
Authors: Schofield R. E. , Thornley R. H.
Published: June 2010

Recent developments in mechanical engineering technology have highlighted the inadequacy of the existing criteria of surface classification. It has been suggested that a bearing area curve and a high spot count are more satisfactory criteria than those utilized hitherto. Research into fields such as the stiffness of plane joints has indicated the validity of these criteria. In order to obtain a quantitative prediction of the magnitude of such parameters it is necessary to endow surfaces with certain mathematical properties. This paper is intended to indicate methods whereby this may be achieved.
Paper 41: Review of Methods of Measurement and Assessment of Surface Form and Texture
Authors: Richards P. J.
Published: June 2010

The purpose of this paper is to discuss current methods of measurement and assessment of straightness, flatness, roundness, and surface texture. Possible future developments will also be discussed. Each method will be discussed on the following bases: scope, accuracy, information available, and cost and convenience of obtaining data.
Paper 4: An Introduction to Design Calculations on a Digital Computer
Authors: Edwards A. J. , Mead B. L.
Published: June 2010

The paper is of a purely introductory nature and is an attempt to provide a brief introduction to performing design calculations on a computer for engineers with no experience of computer techniques.

The paper comments, with a brief description, on a typical computer installation (i.e. I.C.T. 1909); this is followed by a short discussion of problem systems analysis and flow diagramming then a short introductory discussion of the FORTRAN language.

In view of the introductory nature of the paper the problems discussed are kept as simple as is compatible with the subject. It will be realized that more sophisticated approaches could be made to the problems but in order to maintain the paper at an introductory level as a guide to those engineers with no experience of using a digital computer, such solutions are deemed to be beyond the scope of the paper.
Paper 5: Automatic Design of Systems to Avoid Torsional Vibration Troubles
Authors: Bradshaw A. , McCallion H.
Published: June 2010

Currently, systems which include diesel engines are designed and modified to avoid torsional vibration trouble on the basis of experience, and usually in the case of simpler systems a feasible one is found after few attempts. However, even these few attempts can be time consuming if the analysis is performed on a digital computer on a job shop basis.

The purpose of the work described here, using a computer program to start from basic design data for the engines, alternators, and the like, is to achieve automatically a practically feasible and safe solution for the system, allowing for production restraints such as standard ranges of size of the various components. Economic considerations are also included.

The systems examined are unbranched; simple examples being given.
Paper 6: On Predicting Crankshaft Stiffnesses and Frequencies
Authors: Bickley I. J. , McCallion H.
Published: June 2010

Currently design stage calculations of crankshaft stiffnesses involve the extensive use of empirical data. Also, in the calculation of loads on main bearings it is customary to assume the load on any throw to be equally distributed between adjacent main bearings. Before a more realistic approach to the design of crankshafts and main bearings may be made it is necessary to develop and prove a method of analysis. In this paper the finite-element technique is used for predicting the static and vibrational behaviour of crankshafts. The calculated values of axial, torsional, and bending stiffness of a crankshaft, together with its natural frequencies and mode shapes, are compared with experimentally determined values.
Paper 7: The Prediction of Diesel Engine Performance and Combustion Chamber Component Temperatures Using Digital Computers
Authors: Janota M. S. , Hallam A. J. , Brock E. K. , Dexter S. G.
Published: June 2010

The development of digital programs for predicting the performance of multi-cylinder, turbo-charged diesel engines, and the temperature distribution in engine components is described. The performance program incorporates the relatively simple ‘filling and emptying’ method, with the turbo-charger compressor and turbine as boundary conditions, to calculate transient gas conditions.

In the second part of the paper a description is given of the metal temperature program assumptions and use, including the deduction of the surrounding fluid conditions.

The accuracy and limitations of the performance program is demonstrated by comparing predictions and measurements on an experimental 2-stroke single cylinder diesel engine operating under simulated turbo-charged conditions.

The practical applications of the programs to medium speed 2- and 4-stroke engines are illustrated, and the economics of their use as a design aid are discussed.
Paper 12: Computation of Scavenging and Supercharging of Internal Combustion Engines
Authors: Eberle M.
Published: June 2010

A universally adaptable digital computation program for the calculation of scavenging and supercharging has been worked out. The program can be used for the evaluation of existing and new engines cycles. It permits the simultaneous calculation of the thermodynamic state for engines with any number of cylinders, in the admission- and exhaust-receiver (joint receiver or single receiver) and in piston-underside pumps, utilized as a scavenge aid. Any given pressure—volume—characteristics of blowers, compressors and turbines can be included in the calculation. In particular this program is very suitable for the calculation of scavenging and combustion including effects of heat transfer.
Paper 13: The Dynamics of Valve Mechanisms
Authors: Crutcher D. E. G.
Published: June 2010

The paper deals with a computer program that has been developed to study the dynamic behaviour of poppet valve mechanisms. A theoretical analysis is performed on a single mass, single degree of freedom system subjected to internal and external viscous damping and Coulomb friction, representing a valve mechanism with flexible overhead linkage. Measurements have been made on engines so that computed and experimental results could be compared in order to test the program. The effect on performance of varying the dynamic parameters of valve mechanisms is investigated with the computer program.
Paper 14: Analysis of Valve Gear Dynamics with a Digital Computer
Authors: Wagstaff P. R.
Published: June 2010

In this investigation, a pushrod operated valve train is simulated by mathematical models of two, three, four, ten, and fifteen degress of freedom. A number of important features are included in the simulation, such as tappet clearance, linkage separation, valve bounce, and valve spring surge. Solutions of the response to cam lift function under specified running conditions, are obtained by numerical means with a digital computer. These are compared with experimental records of pushrod load and valve displacement on a running engine. The use of similar programs to predict valve gear performance is justified by the excellent agreement obtained.
Paper 15: A Prediction of Some Causes and Effects of Cam Profile Errors
Authors: Brittain J. H. C. , Horsnell R.
Published: June 2010

In the paper numerical methods are developed to enable a cam copy grinding machine to be analysed. A method for computing the former profile necessary to produce a cam specified by a required valve motion is described.

The effects of grinding wheel wear and of machine setting errors on the profile of a production cam are investigated. Use is made of the dynamic analysis of Barkan in predicting the influence of these profile errors on the dynamics of a valve train.

Finally, the possibility of changing the diameter of the former roller to compensate for grinding wheel wear is considered.
Paper 16: Computer Calculation of Stresses in Axi-Symmetric Thermally Loaded Components
Authors: Fiskaa G. , Iversen P. A. , Sarsten A.
Published: June 2010

The paper contains a brief review of some of the approximate methods employed at times for the calculation of thermal stresses in axi-symmetric bodies.

Methods for the calculation of temperature fields are discussed, and computer programs are described for the calculation of temperatures at discrete points in a rectangular grid network by means of relaxation techniques. Methods for automatic generation of input cards for investigation of systematic variation of design configurations are displayed and automatic plotting of isotherms shown by examples.

A method is described for computer calculation of thermal stresses in axi-symmetric bodies by employing a large number of triangular elements. Use of the program is outlined and various methods for presentation of the results are discussed. Typical results are shown. The present program employs constant temperature and stress over each element, but an advanced version allows a linear variation. This may make direct computer plotting of stress fields possible and do away with the costly manual plotting now required. Extensions of the program to include yield and creep are also discussed.
Paper 17: A Method for the Stress Analysis of Pistons
Authors: Scholes A. , Strover E. M.
Published: June 2010

Existing methods of stress analysis for pistons assume axial symmetry of form and loading; they cannot predict stresses in the region of the gudgeon pin bosses. In the method of analysis proposed in this paper a piston is idealized as a portal, including the gudgeon pin bosses; allowance is made for the restraining effect of the rest of the skirt on this portal; the deformations of piston and gudgeon pin are made to conform.

The idealized problem may now be formulated for solution by a standard structural analysis program; however this involves a considerable amount of hand calculation, especially for the evaulation of thermal stresses. In order to reduce this, a special purpose program was written. This uses the force method of structural analysis and can evaluate both mechanical and thermal stresses.

Stresses measured during rig tests are compared with those calculated using the new method. Good agreement is obtained and, in the authors' view, the use of the ‘restrained portal’ idealization is confirmed.
Paper 19: The Stress Analysis of Diesel Engine Frames by Computer
Authors: Scholes A. , Slater D. J.
Published: June 2010

The analysis of the strength and stiffness of a diesel engine frame can be carried out in two parts; an analysis of the whole frame loaded by the inertia of the moving parts and an analysis of one line loaded by the explosion forces. This paper describes computer programs which have been used to make the above analyses in more detail and in less time than is possible by hand calculation.

Results are given for an engine frame in which one program was used to determine the shear and bending forces on the frame and the loads on the ligaments between the various holes in the sides of the frame. Another program was used for the analysis under explosion forces; the walls were divided into a large number of elemental panels (each of side about 2 in) and the stress distribution (both direct and bending) in each of these elements was determined.
Paper 21: Simulation of an Injection System with Delivery Pipe Cavitation Using a Digital Computer
Authors: Brown G. W. , McCallion H.
Published: June 2010

If a suitable computer program is available the specification of a projected fuel injection system may be examined at the design stage. As a development tool, the computer may be used to indicate trends and to supplement experimental data by providing operational details which cannot economically be measured.

Such a program has been developed for a system comprised of a jerk pump with an atlas delivery valve, connected to a multi-hole nozzle by means of an unrestricted small bore pipe. Cavitation has been considered and the mathematical model is shown to be sound.

As an example of the use of the program the results of an investigation to ascertain the influence of certain design parameters on the duration of the injection period in a small system operating at 1500 rev/min are reported.
Paper 22: Prediction of Diesel-Alternator Control Characteristics Necessary for Stable Operation when Connected to a System of Finite Size
Authors: Brown R. L. E. , McCallion H.
Published: June 2010

Controls associated with diesel-alternator sets may be divided into two groups and studied separately. The first group consists of the sequential controls which operate essentially on a logical basis. The second group contains equipment which influences the dynamics of the controlled system.

The action of both groups is modelled on a digital computer.

The dynamics of any power system may be studied by the equations developed to describe the motion of both mechanical and electrical variables. A digital computer program has been written which automatically constructs and carries out stability and vibration studies on an electro-mechanical power system defined by the data supplied to the program.
Paper 4: Contractual Acceptance Tests of Model Turbines
Authors: Mansfield J. N. , McGregor J.
Published: June 2010

Acceptance tests on turbine installations have, in most instances in the past, been undertaken by field tests on the prototype. Greater accuracy, however, is possible by laboratory tests on a model. The cost of model and field tests is examined to show when a model test is an economic proposition. The question of when it is justifiable to have comparative model tests on a number of model turbines from different manufacturers is also discussed.

The realistic level of accuracy attainable leads to reasonable setting of penalty clauses. In many cases penalty clauses have been unrealistic, as the necessary precision on testing, majoration step-up, seal clearance, surface finish, and manufacturing tolerances cannot be achieved. This can result in unnecessary dispute after the tests.

The practical aspects of testing are also covered in the paper, including the need for model installation supervised by the manufacturer, the careful calibration of measuring equipment, and the statistical assessment of results. Finally geometric measurement of the model to ensure homogeneity with the prototype is discussed.
Paper 2: Selection of Lubricant Viscosity Grade for Reciprocating Gas Compressors
Authors: Summers-Smith D.
Published: June 2010

The lubricant in the cylinders of a reciprocating compressor is in intimate contact with the gas being compressed and account must be taken of any effect of the gas on the oil that could interfere with its lubricating properties. With air and carbon monoxide gas temperatures have to be limited to prevent the formation of carbonaceous oil degradation deposits, and with all gases the effect of solution of gas in the oil, with a consequent reduction in viscosity, has to be considered. Based on the analysis of operating experience with compressors handling a wide range of process gases, a range of satisfactory oil viscosity has been defined, using available data on gas solubility in lubricating oils and compressor operating parameters. This provides a means of selecting a suitable viscosity grade of oil for cylinder lubrication which can readily be extended to other gases not considered in the paper.
Paper 4: Measurement of Oil Film Thickness between Rolling Discs Using a Variable Reluctance Technique
Authors: Cameron R. , Gregory R. W.
Published: June 2010

A variable magnetic reluctance technique has been developed and used to measure the thickness of oil films between smooth rolling discs under various conditions of load, speed, and temperature using two different lubricants.

In repeating the experimental conditions of other workers who measured the capacitance of oil films between discs, good correlation is demonstrated between the results of capacitance and reluctance measurements. Since it is unlikely that the two methods suffer from the same uncertainties this correlation can be considered as a recommendation to future users of either method.

The main predictions of the Dowson and Higginson theory are verified by the experimental results, apart from a discrepancy in the dependence of h0 upon the dimensionless parameter U0·7 when thick films are developed. In this region observations are qualitatively more in keeping with the thermal theory of Cheng

An application of the reluctance technique to the measurements of oil film thickness in gearing is proposed.
Paper 5: The Hydrosphere
Authors: Dowson D. , Taylor C. M.
Published: June 2010

A preliminary examination of the bearing indicates that it is not capable of hydrodynamic action as the fluid film is parallel in the direction of motion. However, in practice it has been found that the bearing can support considerable loads. Earlier papers by the authors have examined the proposal of Shaw and Strang that the inertia of the lubricant could account for the load capacity of the bearing. This contention was rejected by the authors, and after other possible explanations had been investigated it was concluded that thermal distortion was the most likely cause of the load-bearing capacity. In this paper recent work will be reported which supports this proposal. The analysis of fluid inertia effects is summarized for a continuous hemispherical seat whose surface is disturbed only by the central lubricant supply hole (the grooveless case). The paper also presents experimental results and an approximate analysis of the thermal distortion for a hydrosphere seat with four lubricant grooves running from the supply hole to the equator along longitudinal lines.
Paper 6: Hydrodynamic Stability of the Flow between Eccentric Rotating Cylinders: Visual Observations and Torque Measurements
Authors: Castle P. , Mobbs F. R.
Published: June 2010

The effect of varying the eccentricity on the appearance of Taylor vortices in journal bearing oil films, and the subsequent transition to turbulent flow, has been studied by means of visual observations and torque measurements.

The vortices have been made visible using a suspension of aluminium paint pigment in the fluid, and also by dye injection, in an apparatus having a perspex outer cylinder.

When the cylinders are eccentric, transition from laminar to turbulent flow is observed to proceed in four stages, an additional instability being present when compared with the concentric cylinder case. Only the second of these transitions causes a distinct change in the slope of the torque–speed characteristic.
Paper 9: An Investigation of the Friction and Lubrication in Human Joints
Authors: Dowson D. , Longfield M.D. , Walker P.S. , Wright V.
Published: June 2010

The work carried out applies to lubricated sliding surfaces in living and artificial human joints, with particular application to the hip, one of the principal load-bearing synovial joints in the body.

Results are presented concerning the dimensions of the fluid-filled space between the articular surfaces of an unloaded human hip joint. The surface quality of articular surfaces has been assessed in a number of cases.

Friction and lubrication experiments have been carried out on a reciprocating type of test machine using samples of articular cartilage and various artificial materials.

It is hoped that the information gained from these experiments will lead to a clearer understanding of the load-carrying capacity of a human joint which is lubricated with synovial fluid.
Paper 10: An Experimental Investigation into the Performance of Sleeve Bearings Subjected to a Range of Alternating Loads
Authors: Patrick J. K.
Published: June 2010

Two dynamically loaded testing machines are described. These testing machines utilize a balanced pressure piston for the detection of tensile stresses in the oil film, and a test bearing housing mounted in an externally pressurized bearing for the measurement of bearing friction.

Oil film pressure surveys indicate areas of general cavitation preceded by troughs of subcavity pressures in which the oil film sustains tensile stresses during periods of increasing dynamic load.

Typical journal centre paths and summary curves of eccentricity ratio versus Sommerfeld number are presented for a range of alternating loads and load/journal speed ratios. None of the speed ratios examined displayed zero load capacity.

Greater cyclic variations of bearing friction than those previously reported for journal friction were measured under alternating loads.

Thin film operation occurred within the range of alternating loads examined, and in all cases the mean friction force was greater than that measured under static loads.
Paper 12: Mild Wear of Unlubricated Hard Steels in Air and Carbon Dioxide
Authors: Clark W. T. , Pritchard C. , Midgley J. W.
Published: June 2010

A study has been made of the wear of various hard steels sliding unlubricated in dry air and in dry carbon dioxide at temperatures up to 500°C. Over the range of loads and speeds employed the wear is of a mild character and the wear debris is of oxide particles, no metallic debris being formed. The characteristics of the wear process depend on the type of oxide formed under the particular conditions of specimen temperature and surrounding atmosphere.

In dry air, the wear rate increases with temperature to a maximum which depends on the type of steel, and then decreases at higher temperatures. Below the maximum, α-Fe2O3 is formed and is swept clean of the surface by the sliding process. The oxidation rate determines the wear rate which is independent of the load at constant specimen temperature. Above the maximum the spinel (Fe3O4) type oxide is formed which is adherent and wear protective.

In dry carbon dioxide, spinel oxide is formed at all temperatures in the range 20–500°C and the wear rate is low, except at high temperatures when the steel becomes too soft to support the protective layer.
Paper 13: Cavitation and Viscosity between Plain Annular Thrust Surfaces
Authors: Nau B. S.
Published: June 2010

The configuration investigated corresponds to that of a face-seal or ungrooved parallel-face thrust bearing. Film thicknesses and temperatures, and shear stresses were measured for various operating conditions with mineral oil supplied at low pressure to the inner edges of the annuli.

Analysis of the experimental results confirms the importance of the bearing parameter, 6ηω02/ h02, in determining the load carried hydrodynamically. At a given temperature the mean effective viscosity of the lubricating film depends on the shear rate, for values in the range 106–107 s–1, decreasing linearly above a threshold value. The cause of this phenomenon is believed to be cavitation occurring in the film.
Paper 14: Experimental Observations on Ball-Mounted Tilting Thrust Pads
Authors: Hemingway E. W.
Published: June 2010

By the use of capacitance probes mounted in the rotor of a thrust bearing test rig the operating conditions of a tilting pad thrust bearing were investigated and compared with the results from analytical investigations. Observations of minimum film thickness show closer agreement with theory than do earlier investigations. It is considered that the differences which remain are due to ( a) the exclusion from the theoretical analyses of the effects of pad deflection, and ( b) inaccuracies in film temperature measurement. Experimental values of coefficient of friction at heavy load show good agreement with theoretical predictions.
Paper 15: Solutions for Flow in a Bearing Groove
Authors: Ettles C.
Published: June 2010

The flow regime in a transverse feed groove is considered and various assumptions to make the problem amenable to theoretical analysis are discussed. A finite-difference method for solving the varying viscosity, two-dimensional Navier–Stokes equations is described. A non-uniform mesh is used and dissipation is taken into account. The flow is assumed to be laminar. Solutions are given for flow in square and rectangular grooves for efflux Reynolds numbers in the range 1–50. Values are given for circulation flow, hot oil carry-over, friction, ram pressure and Nusselt number. It is suggested that the Nusselt number for flow in a transverse groove has a constant characteristic value which could be of value to designers once firmly established.
Paper 17: A Self-Acting Parallel Surface Thrust Bearing
Authors: Bennett A. H. , Ettles C.
Published: June 2010

This paper describes the analysis, design, and testing of a one-piece hydrodynamic thrust bearing with an initially flat surface, which has a performance similar to conventional pivoted pad thrust bearings. The leading portion of each pad is undercut allowing it to deflect elastically under load and form a wedge-shaped film. Analysis of the configuration used is particularly simple and gives good agreement with experimental results. This cantilever bearing is compared quantitatively with the plain land type and is shown to have a greatly superior performance. Comprehensive instrumentation mounted in both the rotor and the bearing gave an accurate account of the operating conditions.
Paper 18: Carbon-Fibre Reinforced Polymers as Self-Lubricating Materials
Authors: Giltrow J. P. , Lancaster J. K.
Published: June 2010

An investigation of the friction, wear, and mechanical properties of polymers reinforced with different proportions of two types of carbon fibre is described. During dry sliding against steel, coefficients of friction of the composites lie within a common range of 0·25–0·35 at high fibre concentrations, and rates of wear can be reduced by factors of more than 103. Fibre reinforcement can also greatly improve the strength, stiffness, and deformation under load. The most important factor influencing the wear rate is the amount of fibre present: the strength is more dependent on adhesion at the fibre–polymer interface.

The practical applications of carbon-fibre reinforced polymers are discussed.
Paper 21: Measurements of Friction and Wear under Conditions of Dynamic Excitation
Authors: Barker K. , Kaliszer H. , Rowe G. W.
Published: June 2010

An experimental study is being made of the friction and wear of pins of different materials in sliding contact with a rotating mild steel disc. A load is applied by dead weights and the excitation is introduced either by out-of-balance in the wheel or by an electromechanical vibrator attached to the loading arm. Stepless speed variation up to 60 ft/s is provided. The friction force, temperature, and worn volume are recorded continuously.

Under light loads a synchronous impulsive force appears to decrease the shear strength of the lubricant–metal interface, whereas under a heavy load it does not have a significant effect on the interfacial contact.

Synchronous vibrations alter the wear pattern of a phosphor-bronze pin. The running-in period is extended, but the final wear rate is greater. Changes in the running-in characteristics of a steel pin are not observed.
Paper 22: Elastic Distortion of Journal Bearing Housings
Authors: Ibrahim S. M. , McCallion H.
Published: June 2010

The elastic distortion of journal bearing housings can have a significant influence on the lubricant film thickness and, consequently, upon the oil pressure distribution. The present investigation is aimed at putting orders of magnitude on the housing distortion by finite element methods. The influences of a number of factors on these distortions are illustrated and discussed.
Paper 23: A Theoretical and Experimental Investigation of the Effect of Elastic Distortions on the Performance of Journal Bearings
Authors: Brighton D. K. , Hooke C. J. , O'Donoghue J. P.
Published: June 2010

This paper describes details of a solution to the finite journal bearing problem, including the effects of elastic distortions in the bearing liner. Solutions for the particular case of a bearing of length to diameter ratio of 1, outside to inside diameter ratio of 1·3, and Poisson's ratio of 0·4 have been obtained and the results are compared with experimental results obtained with a Delrin plastic bearing. Good agreement between theory and experiment has been obtained.

The theory, which is applicable to soft shell bearings supported in a rigid housing, predicts that:

(1) the ratio of the peak pressure to the average pressure is reduced; (2) the bearing stiffness is reduced; (3) the minimum film thickness for a given load is reduced by elastic distortions at eccentricity ratios less than unity; and (4) the friction is reduced.
Paper 13: Standards for Safe Handling Characteristics of Automobiles
Authors: Milliken W. F. , Dell'Amico F.
Published: June 2010

The fundamental considerations involved in the handling qualities of motor vehicles are first reviewed in the context of guidance and control requirements. The contribution of the vehicle to safety and the complexities of the driver–vehicle quality are reviewed first in general terms then in specific terms involving various methodological approaches. These approaches include vehicle response parameters and task performance. A brief outline of the history of the development of aircraft handling qualities criteria and specifications is given, and the aircraft experience is examined with a view towards comparing the problem areas common to both classes of vehicles. An outline of an experimental approach to handling standards using task performance is given.
Paper 1: Crash Barrier Developments
Authors: Jehu V. J.
Published: June 2010

The search for economical barriers capable of redirecting without mishap high-speed vehicles and others out of control is being intensified in many countries.

Existing warrants for road-edge and median barriers are briefly reviewed, together with accident experience with median barriers.

Full-scale dynamic testing recently carried out in the U.S.A., Germany, the Netherlands and the United Kingdom is outlined, and conclusions are drawn regarding the inadequacy of some barriers previously thought to be satisfactory, and the ways in which increased barrier effectiveness is being achieved.
Paper 10: The Importance of Driver Limitations in Vehicle Control
Authors: Irving A. , Bowles T. S.
Published: June 2010

Rapid advances in the performance of motor vehicles have emphasized the limitations on the abilities of drivers. Attempts to define and measure abilities relevant to driving tasks are illustrated with reference to perception of speed, decision making and tests of basic visual abilities. Some of the special problems of the applied experimental psychologist become evident in the description of these studies. Many areas of research relevant to driving justify further extensive research effort.
Paper 2: Some Aspects of the Development of the LVA24 Traction Engine
Authors: Dolenc A. , Lees R.
Published: June 2010

Lightweight design, high speed and high mean pressures permit high specific output of diesel engines but these are normally associated with high mechanical and thermal loading of critical parts.

The paper outlines the approach to the development of the Sulzer LVA24 traction engine and explains the practical experience gained with the components.
Paper 7: Laser Power and Energy Measurement by Photoelectric Techniques
Authors: Firth K. , Davies M. B.
Published: June 2010

The use of photoelectric devices for measuring the output power and energy of pulsed and c.w. lasers is well established. This paper describes the principles, limitations, and advantages of the method. The precautions which must be taken to ensure accurate and reproducible results are also discussed in some detail.
Paper 13: Lasers in the Visualization of Surface Strain and Vibrations
Authors: Butters J. N.
Published: June 2010

Laser light has widened the horizons of applied interferometry both by simplifying existing techniques and opening up a new field where holography is utilized to provide a master or reference wavefront. Whilst retaining many of the advantages of classical interferometry the new methods are simple in application and will accommodate almost any surface finish. Examples of application include an investigation of performance for pressure transducer diaphragms and the development of an engine rocker design. A slight modification to the technique enables measurement and visualization of vibration amplitudes and modes. Application to a turbo-charger impeller investigation and a turbine blade inspection are given.
Paper 8: Engine Tuning to Minimize Exhaust Emissions
Authors: Sutton D. L.
Published: June 2010

With the minimum amount of time available to satisfy impending pollution regulations, a hurried programme of engine research and development was embarked upon to reduce emissions by the simplest and quickest means.

Early attempts with air injection methods had shown promising results, but installation problems resulted in efforts directed towards an engine tuning approach.

With lean set carburation and retarded ignition, tests showed that emission levels could be reached which were within striking distance of the proposed limits.

Analysis of the various modes of operation showed that deceleration peaks, and in the case of manual transmissions, gear change peaks, were highly contributing factors.

A simple type poppet valve incorporated in the throttle plate of the carburettor, and set to operate at a given manifold depression, considerably reduced emissions during deceleration and gear change, bringing composite values within the prescribed limits. Further development of the valve was undertaken and is described in the text.

The development of systems involved investigation into carburettor metering, mixture preparation, ignition timing, temperature compensation, throttle damping, and fuel cut-off.
Paper 18: Emission Control by Carburation
Authors: Lawrence G. L.
Published: June 2010

This paper presents basic data and information relating to the experience gained from further development work associated particularly with the application of ‘CDSE’ carburettors and ‘Duplex’ manifold systems to a wide range of engines.

It is intended to be read against the background of the earlier papers published on the subject (1) (2)†.

No attempt has been made in this short paper to examine particular criteria in depth, especially since many of the developments are still in the experimental stages.

The basic proposition presented is that intake system treatment of the induced charge is more viable commercially than alternative techniques to reduce exhaust pollutants below the legislated standards and that close limit fuel metering consistency is in any event indispensable to adequate field results, whatever system be adopted.
Paper 15: Factors in the Design of Automatic Flow Benches for Carburettor Inspection
Authors: Lawrence G. L. , Firth R. J.
Published: June 2010

This paper examines the basic parameters concerned in the definition of automated flow bench equipment for the production control of carburettor metering standards—particularly as they are concerned in exhaust emission control programmes—and discusses some of the problems encountered during the design and development phases.
Paper 9: The Sampling and Measurement of Exhaust Emissions from Motor Vehicles
Authors: Soltau J. P. , Campbell K.
Published: June 2010

The development of apparatus and systems to reduce exhaust air pollution from motor vehicles was hampered initially by the lack of suitable quantitative measuring apparatus. Great improvements have taken place and accurate measurement of pollutants can now be made, either in the form of continuous records, or of an average value, over a period of time or cycle. The principal instrument in current use is the rapid response non-dispersive infrared gas analyser. Apart from carbon compounds it can also detect with accuracy oxides of nitrogen.

Future trends in pollution measurements are orientated towards the evaluation of the mass emitted during a predetermined cycle instead of the average concentration. With this in view, new sample collection methods have been developed, such as total bag sampling, and variable dilution sampling.

The B.T.C. Analytical Committee was formed four years ago to advise on and discuss exhaust gas measurement techniques. Amongst its achievements have been the establishment of gas and car correlation schemes and the laying down of instrument specifications.
Paper 4: The Effect of Combustion Chamber Shape and Other Engine Design Factors on Exhaust Emissions
Authors: Dartnell P. L. , Goodacre C. L. , Lamarque P. V.
Published: June 2010

A Heron combustion chamber engine of 2 litre capacity has been utilized to investigate the effect of combustion chamber shape, increased mixture movement, valve timing, mixture formation, and reaction in the exhaust system on engine performance and level of exhaust emissions using the seven-mode U.S. Federal cycle.

Such factors as carburettor weakening and limitation of intake manifold vacuum during overrun have been included in this investigation, and it has been shown that it is possible to reduce exhaust emissions and also satisfy the current U.S. requirements with an engine giving acceptable performance, improved economy, and unaffected reliability.

Much of the information reported may be negative in terms of improvement to exhaust emissions by detailed engine design. Nevertheless, some positive conclusions have been reached as a result of this work, and it is hoped that this will draw forth more informed discussion than the authors have been able to assemble from the work attempted with one basic engine.
Paper 2: The Nature and Cause of Diesel Emissions
Authors: Millington B. W.
Published: June 2010

The purpose of this paper is to review, necessarily rather superficially, the broad question of emissions from diesel engines and their relation to combustion as seen from an engineer's point of view.

From the previous paper it will be realized that smoke is the emission currently under strongest scrutiny. Nevertheless, as gasoline engine emissions are brought under more rigorous control there also will be pressure to control unburnts, oxides of nitrogen, and other emissions from diesel engines.