bluuebunny/crossref_metadata_2025_split huggingface dataset:
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 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 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 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 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 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 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.