bluuebunny/crossref_metadata_2025 huggingface dataset:
Hospital antibiotic prescribing successfully modified by ‘immediate concurrent feedback’
Authors: SETO WING‐HONG , CHING TAI‐YIN , KOU MAYBELLE , CHIANG SAU‐CHU , LAUDER IAN J. , KUMANA CYRUS R.
Published: October 2008

To determine the effectiveness of ongoing immediate concurrent feedback (ICF) in minimizing ‘inappropriate’ sultamicillin or co‐amoxiclav prescribing via the parenteral route (i.e. when the oral route was accessible and not contraindicated), a prospective controlled audit was carried out on hospital inpatients over a 20 month period.

After an education programme to promote oral rather than unnecessary intravenous (i.v.) use of sultamicillin, co‐amoxiclav and certain other drugs, an ongoing ICF strategy was instituted.

ICF entailed issue of memos on the following day to prescribers of i.v. sultamicillin or co‐amoxiclav for inpatients in whom this route was deemed ‘inappropriate’, by a specially trained nurse using strict objective criteria. The memos recommended oral prescribing (particularly of co‐amoxiclav, currently the less expensive alternative).

After starting ICF, there were consistent, clinically and statistically significant reductions in the monthly proportions of (i) admissions prescribed i.v. sultamicillin or co‐amoxiclav (38%P < 0.001), (ii) those in whom the route was ‘inappropriate’ (75%, P < 0.001), and (iii) corresponding ratios of i.v./oral usage and expenditure, oral sultamicillin/co‐amoxiclav usage and expenditure, as well as total and per admission expenditure on i.v. forms (> 43%, P < 0.01).

For i.v. cefuroxime (for which there was no ICF) and its oral counterpart cefuroxime‐axetil, there were no comparable changes in usage or expenditure.

This simple, ongoing ICF strategy was effective and well accepted; estimated net monthly savings being HK$26–30,000.
Systemic absorption of nebulized morphine compared with oral morphine in healthy subjects
Authors: MASOOD A. R. , THOMAS S. H. L.
Published: October 2008

The inhalation of nebulized morphine has been advocated to treat dyspnoea and pain in patients with cancer. We have compared plasma morphine concentrations in healthy volunteers after nebulized (50 mg in 4 ml saline), oral (10 mg solution) and intravenous (5 mg) morphine sulphate. Bioavailability was estimated by dividing the morphine concentration AUC/dose by that obtained after intravenous morphine. Peak plasma morphine concentrations were achieved more rapidly after nebulized than oral morphine, occurring within 10 min in all subjects. The systemic bioavailabilities of morphine (mean ± s.d.) were 5 ± 3% and 24 ± 13% for the nebulized and oral routes respectively. Nebulization is a rapid but inefficient method of administering morphine. It may provide more rapid pain relief compared with oral morphine but clinical studies are needed to confirm this.
The use of medication and alcohol among the Spanish population
Authors: RIO M. C. DEL , PRADA C. , ALVAREZ F. J.
Published: October 2008

The 1993 Spanish National Health Survey data were used to estimate how frequently both medication and alcohol were used among 21084 people over 16 years of age. A total of 47.1% of the population, especially women and an increasingly older section, had taken some kind of medication during the previous fortnight. A total of 9.8% of the population took medication and alcohol together. This was more frequently observed among men than among women, and especially so among the older age groups. These data reveal that concomitant alcohol and medication use is frequent among the Spanish population, and suggest a need to devote much more attention to this potential problem.
MOIRÉ STRAIN GAUGES
Authors: KOSTAK BLAHOSLAV , POPP KAREL
Published: October 2008

General features of the use of spiral grids in the Moiré technique are analysed theoretically. Equations of various types of Moiré fringe patterns are presented, which relate to superposition of circular, spiral, and parallel‐line grids.

Goniometric compensation is proposed on Moiré fringes. The question of differentiation of the sign of strain is solved. Comparison is made with pure circular‐grid systems.

The principles developed are aimed at strain measurements with the use of Moiré gauges.
COMPARISON OF FRINGE MULTIPLICATION AND TARDY COMPENSATION METHODS FOR A FROZEN STRESS INVESTIGATION
Authors: KENNY B. , HUGILL J. W.
Published: October 2008

A practical application of the fringe multiplication method is described. Using techniques reported by Post, the method was found to be convenient and less time consuming than the normal Tardy compensation technique which was used as a comparison. For the cases studied it was found that fringe multiplications of 7x gave equivalent fringe order distributions to the Tardy technique.
STRUCTURAL MODEL ANALYSIS WITH THERMOPLASTICS
Authors: WALLACE G.
Published: October 2008

The use of small scale models as an experimental method of analysing structural behaviour offers an attractive solution to many problems, and thermoplastics can be considered profitably as structural materials for such models. Xylonite was probably the first thermoplastic used in this way, but its relatively poor dimensional stability often proved a serious disadvantage.

In the present paper vybak is advocated as a superior material, for which bonding and strain gauging techniques have been established. Comparisons are made between the material properties of vybak and other thermoplastic materials, and examples of experimental work with vybak models are given.
THE USE OF SPARK MACHINING IN THE DETERMINATION OF LOCAL RESIDUAL STRESSES
Authors: DENTON A. A.
Published: October 2008

A method of measuring residual stress by a stress relief process in flat bars and cylindrical specimens is developed and correction factors discussed.
THE SLIT SOURCE AND GRATING METHOD IN PLANE STRESS PROBLEMS
Authors: THEOCARIS P. S. , KOUTSABESSIS A.
Published: October 2008

A simple method is presented for measuring partial slopes of transparent specimens in plane stress. A monochromatic slit source is used to illuminate a line amplitude grating and the transparent specimen is interposed between the slit and the grating. The deformed lateral surfaces of the loaded speciment distort the lines of the grating and yield contours of equal partial slope of the specimen in a direction normal to the direction of the rulings of the grating.

The method is used for determining the magnitude and gradients of the sum of principal stresses in plane elastic problems.
MEASUREMENT OF INTERNAL STRAIN IN CONCRETE
Authors: McKILLEN R. R. , BRADING K. F. , WILLIAMS A.
Published: October 2008

Methods of strain measurement in concrete have been investigated experimentally. This paper reports work on embedded resistance strain gauges mounted on concrete and other forms of gauge carrier, techniques for strain gauging embedded steelwork, results of gauge factor tests on briquetted and unbriquetted vibrating wire gauges, and gauge responses to temperature variations. Proposals are outlined for future work particularly on stress meters as distinct from strain gauges.
A CREEP STRAIN GAUGE FOR IN‐PILE MEASUREMENTS ON REACTOR PRESSURE TUBES
Authors: EDWARDS L. , McCALVEY L. F.
Published: October 2008

A creep gauge based on a differential transformer and mechanical magnification measures a diametral expansion of less than 0‐1X10‐6 in/in per hour on a 5 in diameter tube at 300 deg. C in a reactor environment.
EVALUATION OF A FULL‐BRIDGE E.R. STRAIN GAUGE FOR MEASURING TRANSIENT THERMAL STRAINS
Authors: PROCTER E. , MITCHELL D. H.
Published: October 2008

Transient thermal strains daring start up of power station plants are measured by weldable gauges consisting of two longitudinal and two transverse Nichrome foil grids on a rectangular steel shim spot‐welded to the turbine casing along a central line of the shim. Performance tests and results are described for these ganges.
RESISTANCE MATERIALS FOR HIGH‐TEMPERATURE STRAIN MEASUREMENT
Authors: GRINDROD A. , NODEN J. D.
Published: October 2008

The performance of some commercially available base and noble metal resistance alloys usable as strain sensors in high temperature strain gauges is experimentally assessed with emphasis on the determination of post yield strain under these conditions.

In order for Cu‐Ni resistance alloys to be used satisfactorily at 600 deg.C, gross surface oxidation must be prevented by an argon shield and the surface of the sensor must be pre oxidised to inhibit grain boundary attack from partial pressure of oxygen in the argon atmosphere.
LEAST SQUARES SMOOTHING OF EXPERIMENTAL DATA USING FINITE ELEMENTS
Authors: HINTON ERNEST , IRONS BRUCE
Published: October 2008

A program for interpreting Moire fringe data using a digital computer is described. The finite element technique overcomes certain intrinsic defects of existing methods which use polynomials, and promises to give better results, especially where stress concentrations are present. An experimental example compares the technique with the polynomial technique.
STRESS DISTRIBUTION AROUND HOLES AT THE ENDS OF A CRACK
Authors: AL‐SIKAFI Q. H. , LANCASTER P. R. , MITCHELL D.
Published: October 2008

Stresses around holes of equal size drilled at the ends of a crack are determined for uniaxial tension normal to the crack by a combined photoelastic and brittle lacquer technique avoiding difficulties of exactly locating isoclinics. The stress concentration factor decreases continuously with increasing hole size until the crack is displaced by a single hole.
THE EFFECTS OF EARTH LEAKAGE ON ELECTRICAL RESISTANCE STRAIN GAUGES
Authors: WEIR R. M.
Published: October 2008

An attempt is made to clarify the effects and the measurement of earth leakage in a strain gauge installation. A rough basis is provided on which the seriousness of the earth leakage effects may be estimated for a single active gauge in a Wheatstone Bridge Circuit.
A METHOD FOR MEASURING THE FRETTING MOTION OF FLYWHEELS
Authors: BLUM A. E.
Published: October 2008

Araldite strips with bonded electric‐resistance strain gauges are accommodated in pockets machined into the flywheel and are cemented to both the flywheel and the adjoining crankshaft. flange. Relative motion between the two components strains the strips and is indicated by amplified electrical output.
APPLICATION OF GRIDS TO PLASTICS FOR THE MOIRE FRINGE METHOD OF STRAIN MEASUREMENT
Authors: STRANNIGAN J. S. , McGREGOR J.
Published: October 2008

There has been considerable interest during recent years on the measurement of strain using the moiré fringe method. This report reviews the techniques of applying grids to specimens and gives details of methods used at NEL. Strain measurements on a simple tensile test specimen using the moiré mismatch technique are compared with those obtained with a Linley extenso‐meter.
STRAIN MEASUREMENT IN REINFORCED CONCRETE SLABS
Authors: MUSPRATT M. A.
Published: October 2008

Electrical strain gauges are used for measuring steel and concrete strains in reinforced concrete slabs subjected to short‐term tests to failure. Strain readings are taken on the compression and tension faces of the concrete and on the reinforcing steel.
UTILIZATION OF STRAIN GAUGES OVER LONG PERIODS OF TIME AT ELEVATED TEMPERATURES
Authors: WARREN J. W. L.
Published: October 2008

Tests are described for the evaluation of a particular strain gauge/cement combination under steady loading at elevated temperatures over long periods of time. Although the strain gauges showed a relaxation of their reading with time, due to creep of the gauge backing and cement, it proved possible to correct for this effect to within the scatter associated with the specimens and the instrumentation. It is concluded that application of such corrections to other strain gauge/cement combinations should be possible.
GAUGE FACTOR EVALUATION WITH DIGITAL READ‐OUT
Authors: SCOTT I. G.
Published: October 2008

New gauges, new techniques or new operators can be checked by measurement of the gauge factor with a simple circuit which is described and gives direct digital reading of the factor.
A UNIVERSAL INSTRUMENT FOR FRINGE MULTIPLICATION
Authors: McNICHOLAS J. B.
Published: October 2008

Expenditure of time for conventional photoelastic analysis of two‐dimensional models under load and of frozen‐stress slices is minimised and the applications of materials of low optical sensitivity either for stress or for strain are extended by the use of this instrument, which is designed for incorporation in any conventional transmission bench. Data may be analysed directly by travelling microscope or deduced from photographs. The light may also be passed into a separate darkroom unit and the faint images projected on to a screen for observation and for recording of information on photographic paper which is then rapidly processed.
A 3‐DIMENSIONAL INVESTIGATION OF SHRINK‐FIT STRESS DISTRIBUTIONS
Authors: MATHER J. , BAINES B. H.
Published: October 2008

The paper gives an account of the experimental procedures adopted in investigations concerning shrink‐fit stress distributions in epoxy resin model assemblies. The use of the stress‐freezing technique is discussed with reference to the shrink‐fit problem. Information on model material properties is also presented, with particular emphasis on an assessment of the creep level.
STRAIN MEASUREMENT ON FILAMENT‐WOUND STRUCTURAL MEMBERS
Authors: WONG H. Y. , GORDON R. D.
Published: October 2008

Owing to the heterogeneity of a filament‐reinforced structure, strain measurement cannot be carried out easily with common methods. Incorporation of fine electrical resistance wires in the windings allows strains in the direction of the wires to be measured by the wires acting as strain gauges. The technique has been tested in a circumferentially wound glass filament tube subject to internal pressure and the results have proved much more reliable than those obtained by ordinary strain gauges bonded to the surface.
ANALYSIS OF PHOTOELASTIC DATA FOR THREE‐DIMENSIONAL STRESS SEPARATION
Authors: ALLISON I. M.
Published: October 2008

The principles of stress separation, by the classical and by Tésar's methods, from observations on slices of frozen‐stress photoelastic models are explained with illustrations for axisymmetric and general three‐dimensional problems and for problems with a plane of symmetry.
Experimental features of residual stress measurement by X‐ray diffractometry
Authors: KIRK D.
Published: October 2008

This paper is the second in a series of three which covers (1) theoretical considerations, (2) experimental features and (3) practical applications of X‐ray diffractometer techniques to the accurate determination of residual macrostresses. The first paper appeared in the April 1970 issue of “Strain”.
Direct measurement of fatigue damage in aircraft
Authors: BLACKBURN E. J.
Published: October 2008

A fatigue life gauge, mounted on a mechanical amplifier and bonded to a structure, will integrate the load/frequency pattern to which it is exposed. Subject to static calibration establishing the strain/load relationship registered by the device, gauge manufacturers data will closely predict the output for programmed loading within the range of 0–2 to 40 ohms. The purpose of the device is to compare the rate of loading, accumulated by a test structure, with the rate accruing to similar structures undergoing variable service loading. Inasmuch as this loading affects the fatigue life of a component, the device will monitor fatigue damage. Some agreement is shown between laboratory test of an aircraft fin and measurements taken during routine flying. The device is sensitive to change in aircraft utilisation. In the case of fin structure, no correlation exists between the measured damage factor and the damage assessed by the standard aircraft fatigue meter.
Strain measurements at the GPO Tower, London
Authors: EATON K. J. , MAYNE J. R.
Published: October 2008

This paper describes a research project undertaken at the Building Research Station to measure wind pressures on the GPO Tower, London, and dynamic strains in the tower shaft. The development of a suitable pressure transducer, which uses strain gauges as sensors, is described together with the installation at the tower. Some of the problems of strain gauging large civil engineering structures are outlined.
Use of pre‐encapsulated strain gauges for water pressure tests on site‐built pressure vessels
Authors: DODD P. , WELSH R. L.
Published: October 2008

Methods are described for reliable strain gauge measurement during water pressure tests on site‐built vessels. For efficient and economic waterproofing the gauge is pre‐encapsulated in epoxy resin before being bonded to the structure. The additional mechanical protection makes the method particularly suitable for site application.
Determination of the working length of a strain gauge calibrating beam
Authors: COUTTS J. A. , GREEN K. P.
Published: October 2008

Extended and strain–gauged calibrating beams, which can be displaced longitudinally in a four–point loading rig permit accurate determination of variations in gauge output with gauge position between supports. Results show that the working length of the calibrating beam may extend over the whole length of the span between the inner supports.
Strain measurement with particular reference to cast iron
Authors: ROBINSON L.
Published: October 2008

The general planning procedure for development testing at the author's firm is outlined. Strains in static tests of cast iron components under loads simulating service conditions are surveyed by brittle coatings and measured by strain gauges with incremental and shake‐down load application. The fatigue life is then estimated in a novel manner by reference to the S/N curves established by Deere in push‐pull tests on various cast irons. For nonzero mean strains, reference is also made to the static stress‐strain curves for the tested material and to its Goodman diagram so that an equivalent strain reversal can be deduced and the Deere curve applied. For varying loads Miner's rule is invoked.
Use of models to determine the lateral load‐deflection characteristics of pierced shear walls
Authors: REAY A. M. , SHEPHERD R.
Published: October 2008

The necessity to determine the load‐deflection characteristics of a series of pierced shear walls, which provide part of the lateral strength of a complex of multistorey buildings, resulted in the construction and testing of a series of model walls. The methods used are described and typical results are presented.
Stresses in a fuselage model due to concentrated radial loads
Authors: GRAHAM J. , LARKIN J.
Published: October 2008

Experimental values of shear and direct stresses on cross–sections of a fuselage model, due to concentrated radial loads applied to a frame, are compared with values predicted by a matrix force analysis. The results include the effect of cut–outs in the surface of the shell. Comparisons are also made of the direct stress on the inner flange of the directly–loaded frame and of the frames bounding the cut–outs. Results indicate that the degree of accuracy of the theoretical stresses is adequate for the purpose of design.
Load transducers—‐design, manufacture and use
Authors: VIRGOE R. J.
Published: October 2008

Load cells are precision electronic weighing devices, capable of extremely high accuracies, provided that the application is correct. Most cells are designed with the knowledge that there are very few ideal situations but owing to design limitations, external factors and economics, it is not possible to produce perfect units to suit all applications. The methods of installation and use govern the accuracy which is obtained. The principles of construction and application of the bonded strain gauge type of load cell are stated and the methods employed to achieve high accuracy are explained.
Evaluating the quality of strain gage waterproofing compounds
Authors: DITTBENNER GERALD R.
Published: October 2008

I would like to share some information regarding the use of the megohmmeter and strain indicator for evaluating various strain gage waterproofing compounds in a high humidity environment (50 to 100% relative humidity).
Do we measure strain when we measure strain?
Authors: PEEKEL C.
Published: October 2008

Errors can occur in the measurements from a strain gauge installation unless certain precautions are taken. Practical solutions are given to minimise the influence of temperature, moisture etc., to ensure an acceptable zero stability.
The use of photoelastic strain gauges in industrial transducers
Authors: HIGSON G. R.
Published: October 2008

Two types of transducer, using photoelastic strain gauges, developed for use in mines are described. It is believed that robust self–contained transducers of this kind could find wide application in other industries where high accuracies are not necessary.
Impacts on steel and graphite
Authors: McCALVEY L. F.
Published: October 2008

Although it has been accepted for some time that the damage criterion for impact of falling objects is the velocity at impact, there has been little acceptance of the view that velocity at impact determines damage in radial impacts such as occur in charge/discharge of fuel elements or gas induced vibrations in pins in elements. Most A.G.R. tests to date have been based upon interpretation of results from accelerometers to establish acceleration or deceleration values at impact. It is suggested that this practice is misleading. Variation in material properties due to temperature changes affect the stresses set up by impact. This effect is considered in relation to graphite and stainless steel.
On the measurement of transverse sensitivity of strain gauges
Authors: MEYER M. L.
Published: October 2008

The influence of the transverse sensitivity factor n on errors in the measurement of strain are discussed and it is concluded that, providing the factor n is within £0015, its effect may be disregarded in all normal applications. The determination of n on a gauge factor calibration rig is considered and an analysis made of the degree of accuracy attainable.
Resistance strain gauges on thermoplastics
Authors: SWAN J. W.
Published: October 2008

Analysis of structural problems with the aid of scale models constructed in low–modulus thermoplastic materials such as Perspex, Vybak and Darvic is now well established. Measurements of strain and deflexion are complicated, however, by the structure creeping under load and by the effects of changes in ambient conditions of temperature and humidity. Experience shows that these difficulties can usually be overcome by the use of suitable testing techniques, but strain measurements using resistance strain gauges are sometimes regarded critically because these measurements are said to be influenced by the heating effect of the bridge current and the low thermal conductivity of thermoplastics. One aspect of this could be a softening of the model material with heat causing a variation in the value of Young's modulus. At the Naval Construction Research Establishment, Dunfermline, thermoplastic model testing has for many years been a feature of the work in support of structural and theoretical analyses and the information derived from this work shows that the criticisms are unjustified.
Photoelasticity—‐An improvement in the sandwich technique
Authors: THOMPSON D. E. , HARLAND W. G. , UMIST J. H. LAMBLE.
Published: October 2008

The development of the sandwich technique in photoelasticity necessitates a suitable cement. The results of experiments using cyanoacrylate IS 12 in cementing Perspex and Araldite are compared with the results of experiments using resorcinol formaldehyde. These show that cyanoacry/ate is much superior in strength and that it has other properties suitable for the purpose.
State of stress and strain in a rectangular belt pulled over a cylindrical pulley
Authors: DURELLI A. J. , BUITRAGO J.
Published: October 2008

This paper deals with the contact pressure between a belt and the pulley to which it transmits force and with the bending and membrane stresses in the belt. The anticlastic configuration of the belt is also taken into consideration. The commonly known simplified approximate analysis of the pressure, as well as the results of a more elaborated theory, are presented. Also given in the paper are the description and evaluation of several experimental stress analysis methods that can be used to solve the problem. Two– and three–dimensional photoelasticity, thickness measurements and electrical strain gauges were found to be the most practical approaches. The correlation of results obtained, using the theories and the experimental methods, is discussed. It is estimated that the peak contact pressure is 3–5 times that computed using the plane stress assumption. Results obtained will also have application in the design of wire–ropes or cables transmitting forces to sheaves or drums.
Photoelastic stress analysis in fibre reinforced plastics
Authors: MARGETTS A. J. , BOTT T. R.
Published: October 2008

A room temperature technique for experimental stress analysis in three–dimensional fibre reinforced plastics is proposed. The technique is verified experimentally in two dimensions for the particular case of a cold–curing epoxy resin subject to load before the resin has fully hardened. This technique allows strains which are produced by loading to be permanently locked into the epoxy model by the curing process and enables slices to be cut for analysis without disturbance of the fringe pattern. A simple three–dimensional model analysis is presented to demonstrate possible advantages of the technique.
Strain gauge measurement on plastics
Authors: PROKOPEC M.
Published: October 2008

A description is given of tests carried out to investigate the problem of signal instability encountered in the use of electrical resistance strain gauges on plastics. Time response from switch‐on is indicated for 120 ohm wire and foil gauges of various types and sizes, bonded to epoxy resin and energised at 25 V. Wire gauges show a reduction in signal and foil gauges an increase. Results of subsequent tests demonstrate the effects of initial strain, energising voltage, thermal diffusivity of the specimen material and gauge grid area. An indication of gauge surface temperature obtained by thermocouple, is related to degree of drift and energising voltage. Signal stability is improved by coating the gauge with a wax/aluminium‐powder mixture. A data logger with pulse excitation is recommended as the best system and limiting energising voltages are stated.
temperature compensated silicon strain transducer
Authors: CASTLE P. F.
Published: October 2008

A high output semiconductor strain sensing device for use in transducer applications is described. It consists of a Wheatstone bridge network diffused into a small silicon chip and has a maximum strain sensitivity of I00mV/V/1 000 μ e. With the addition of a simple three resistor network, the device can be compensated such that the temperature dependence of the zero strain offset voltage can be reduced to less than 0.1 μ e per C and the temperature coefficient of sensitivity to less than 001% per C. The properties of pressure transducers made with silicon diaphragms into which similar Wheatstone bridges have been diffused, are also outlined.
Numerical experiments on the determination of stress concentration factors
Authors: LAURA P. A. , REYES J. A. , ROSSI R. E.
Published: October 2008

A brief discussion of relevant applications of the finite element method is presented, and two cases of relatively high stress concentration are considered. For a slot with semi–circular ends in a plate subjected to uniaxial stress, the stress concentration factors obtained numerically, by use of the finite element method, are compared with corresponding experimental results. The case of a corrugated hole in a plate under 1:1 biaxial stress is also examined, and stress concentration factors determined using the finite element approach are compared with exact values obtained by application of Muskhelishvili's method.
The influence of isoclinics on photoelastic studies of the stress distribution around a crack tip
Authors: EVANS W. T.
Published: October 2008

A photoelastic investigation of the stresses around edge cracks in a tensile field, is described. The influence of isoclinics on the accuracy of stress intensity coefficients is demonstrated, and the results are compared with theoretical values obtained using the collocation method.
Thermal strains and deformations in cast iron brake discs
Authors: ABBAS S. A.
Published: October 2008

A description is given of an experimental technique for the measurement of thermal strains and deformations in a cast iron brake disc. An experimental rig was used to simulate the heat dissipated at the rubbing path during braking, and thermocouples and strain gauges indicated the temperatures and strains. A/though some non–linearity, thought to be due to the stress–strain characteristics of cast iron, was noted in the curves for measured strain, good agreement was found with the theoretical predictions for both strains and deformations.
The development and evaluation of a fatigue crack length monitoring system for liquid environments
Authors: JERRAM K. , PRIDDLE E. K.
Published: October 2008

The requirements for measurement of crack initiation and propagation are discussed briefly with particular reference to situations of liquid environments where conventional methods are unsuitable.

A technique based on measurement of stiffness has been developed to give continuous record of crack length and a knowledge of crack initiation from a fatigue crack propagation test. The data obtained for EN3A mild steel in air and various liquid environment are in agreement with published values.
Design and manufacture of high precision strain gauge dynamometers and balances at the O.N.E.R.A. Modane Centre
Authors: DUBOIS M.
Published: October 2008

The Modane–Avrieux Large Wind Tunnel Department of O.N.E.R.A. designs equips and calibrates single or multi–component dynamometers and balances for tests in its own facilities. It also undertakes such work as requested by external organisations. The capacities of these instruments range from 0.01 N (0.002 Ibf) to 1 000 kN (100 tonf) and the general accuracy is of the order of 10–3.

The principles and processes governing the design, fabrication and calibration of these transducers are described.
Determination of stress concentration factors for grooves and fillets by the electro–plating technique
Authors: OKUBO H. , KAGAYA C.
Published: October 2008

The electro–plating technique of stress analysis involves the use of copper–plated specimens and measurements are based on the appearance of grains grown in the plated copper as a result of cyclic loading. A description is given of the technique and its application to the determination of stress concentration factors for grooves and fillets on circular shafts subjected to torsion. Results are compared with corresponding published values obtained by other methods.
On the effect of residual birefringence in anisotropic photoelastic materials
Authors: MITTAL R. K.
Published: October 2008

The effect of residual birefringence on isoclinic angle and fringe order is considered for mechanically and optically anisotropic materials. Toupin's4 theory of deformable dielectrics forms the basis of the investigation. Equations are derived for fringe order, stress fringe value and isoclinic angle in linear orthotopic photoelastic materials. The principal effect of residual birefringence relates to the determination of the isoclinic angle. This is particularly so for certain fibre–orientations. Unlike the isotropic case, the isoclinic angle depends on the stress at which it is measured.
Ring gauge for biaxial strain analysis
Authors: BRIDE W. L.
Published: October 2008

The ring gauge performs the same function as a strain gauge rosette by providing three independent signals from which may be deduced the three unknowns in a biaxial strain system, viz. the magnitudes of the principal strains and the directions of the principal axes relative to a datum direction. It is analogous to a delta rosette but possesses advantages over the usual method of cementing three gauges to the surface of the material.
A new self–oscillating strain gauge
Authors: WALLACE R. H.
Published: October 2008

This article describes the development, characteristics and limitations of an invention which enables a dual strain gauge, together with a solid state module, to produce an F.M. signal uniquely related to strain in the gauges. The frequency of this signal can be read by a crystal counter at the end of long leads and through ordinary switches, without error therefrom.
The use of strippable photographic film for moire grating production
Authors: DE CALUWÉ M.
Published: October 2008

Practical details are presented concerning the use of strippable film for the production of moiré gratings. Strippable film is produced primarily for application in graphic arts. The influence of the use of the film on the accuracy of measurement in the direct moiré method is discussed.
An alternative definition of material properties
Authors: MEDLAND A. J.
Published: October 2008

The stresslstrain relation is initially discussed in general form. The normal matrix formulation employing the Lamé Constants and the more ‘practical’ formulation based on the Elastic Modulus and Poisson's Ratio are detailed.

An alternative approach employing the wave speeds of the material as the basic material parameters is discussed. This approach has a number of advantages over the present tensile testing methods. The main advantages are that the properties can be obtained on the actual part or specimen without resorting to destructive testing means, and the data can be collected with the same strain gauge equipment that is to be employed in subsequent testing procedures.

The problem associated with the measurement of short duration, low amplitude pulses is discussed and the broad details of the required instrumentation are given.

Two simple experiments are illustrated in which firstly, the wave velocity in a bar is obtained and secondly, the dilatational and shear wave speeds are obtained in a plate structure.
Rapid analysis of aero‐engine integrity based on strain gauge data
Authors: PEARSON D. S.
Published: October 2008

During testing of a gas turbine engine with strain‐gauged parts, a three‐dimensional plot of stress amplitude and frequency against time (or engine speed) greatly facilitates presentation of data in an easily understandable form. It is shown how advances can be made from such ‘3D’ plots while presenting data rapidly, automatically and still in traditional formats. Examples are presented to indicate how such techniques can save analysis time, improve engineering understanding and enable a more rapid turn‐round of engine tests. The methods described also assist recovery of information which, by conventional methods, would be lost in background interference.
Increasing the voltage output of a Wheatstone bridge having one or two active strain gauge arms
Authors: POPLE J.
Published: October 2008

A method of increasing the voltage output of a Wheatstone bridge having one or two active arms is discussed. An increase of 80% is shown to be practicable without increasing the current in the gauge. This is achieved by using an asymmetrical bridge configuration instead of the more usual symmetrical arrangement. The effect of this configuration on output linearity is considered and a bridge‐balancing circuit is illustrated.
The prediction of spring‐back and residual stress in coiled strip
Authors: SWIFT W. A. C.
Published: October 2008

Cold‐rolled, heat‐treated strip has tensile and compressive stress‐strain characteristics which approximate to those of an ideal elastic‐perfectly plastic material. The paper describes the use of Gardiner's1 equation for spring‐back following pure bending and its application to a rapid method of determining the ratio of the Young's modulus to the yield stress of the material. If, as is often the case, tension is applied to the strip during coiling, the spring‐back equations of Woo and Marshall2 are applied. Woo and Marshall's equations for residual stress are used in non‐dimensional form for both pure bending and bending under tension.
A simple triaxial rig for studying the creep of concrete at elevated temperatures
Authors: LUXMOORE A. , SEKISAMBU S.
Published: October 2008

The design and testing of an apparatus for studying the creep of concrete at temperatures up to 200°C, under triaxial stress conditions, are described. Initial test results confirm that the apparatus is satisfactory
An estimation of plastic zones in a plate with a central hole
Authors: COCKERHAM G. , EATON D. E.
Published: October 2008

A method is described for estimating the size of the plastic zone developing around a central hole in a finite width plate subjected to a monotonically increasing tensile load from a knowledge of the elastic stress field only. The plate is assumed to be subjected to plane stress conditions and to be made from an elastic, linearly strain‐hardening material. Yielding is considered to occur when the Mises criterion is satisfied. Stresses within the plastically deformed area of the plate are evaluated by means of the Prandtl‐Reuss incremental flow rule together with strains increments calculated from the elastic stress distributions. The predicted plastic zone sizes correlate well with those determined experimentally by other workers.
A simple isoclinic indicator for photoelastic studies
Authors: THOMPSON J. C.
Published: October 2008

A simply fabricated inexpensive device is described which, when viewed between crossed polaroids, shows a mutually perpendicular set of isoclinics whose directions coincide with the axes of the polaroids. An outline is presented of the usefulness of his ‘isoclinic indicator’ in photoelastic work, particularly when isoclinic patterns are being photographed for analysis at a later time. The ease with which any error in the orientation of the polaroids can be detected from such photographs is demonstrated.
Forced damped modes of vibration of fabricated unit structures
Authors: BARRON R.
Published: October 2008

Employing a method of vibration testing due to Kennedy and Pancu, with elementary extensions, forced damped modes of vibration of unit fabricated structures have been studied. Theoretical and practical procedures associated with the tests are discussed and the response vector diagrams and mode shape diagrams presented for the third bending mode of vibration of single and combined unit structures. The existence and accuracy of damped modes of vibration are discussed. Test results indicate that by applying this vibration testing method, approximate forced damped modes of vibration of unit structures are uncovered. The dynamic characteristics of these modes will be suitable for use in design and development studies.
The influence of wavelength in the X‐ray measurement of elastic stress
Authors: DOIG P. , FLEWITT P. E. J.
Published: October 2008

The X‐ray diffractometer method applied to the measurement of elastic stresses in mild steel is described. Chromium and cobalt radiation have been used to investigate the effect of X‐ray wavelength on the accuracy of the technique. Effects of elastic anisotropy and beam penetration have been considered.
The role of brittle lacquer techniques in the efficient design of GRP fan blades
Authors: WOOTTON A. J. , MACKINNON J. A. , PATON W.
Published: October 2008

A brittle lacquer mapping technique was used to study the effects of changes in aerofoil construction, GRP laminate configuration, and blade root design in the development of a GRP fan blade. Areas of localised bending of the shell and stress concentration in the root region were located. Potential areas for the nucleation of fatigue damage were highlighted.
Asymptotic analysis techniques for stress concentration regions in plane problems
Authors: THOMPSON J. C. , POST E.
Published: October 2008

This paper describes how asymptotic techniques can be used in the analysis of data from the stress concentration region at the root of a parabolic notch in a thin plate. Three kinds of data are considered: (i) surface strain values from along the notch boundary, (ii) the sum of principal stresses or strains at interior points and (iii) the difference of principal stress or strains at interior points. The merits of the techniques are critically assessed.
Measurement of the thermoelastic coefficient of metals by strain gauges
Authors: DUBOIS M.
Published: October 2008

The modulus of elasticity E of metals and alloys varies, usually, when the ambient temperature θ changes, which is a drawback in most metro logic applications. A thermoelastic coefficient TCE equal to (ΔE/Δθ)/E can be defined. This article shows how this quantity can be measured, dynamometrically and statically, with safety and precision, on a metallic specimen, made of the material under study, on which strain gauges with a known thermal coefficient TCK are bonded.

Experiments carried out at the ONERA Modane‐Avrieux Centre during the manufacture of more than one hundred dynamometers, made of several kinds of metals and gauges, showed that the TCKs, given by the gauge manufacturer, were more stable than the TCEs, which justifies a sufficiently fine measurement of the latter. The TCE values of six different materials, lying between ‐0.44×103 and + 0.33×103, have been determined to within 0.02×10‐3 without particular precautions. An absolute precision better than 0.01×10‐3 may be obtained by this process, which also makes it possible to determine the modulus of elasticity E and the Poisson's ratio v.
Transverse sensitivity errors in rectangular rosettes
Authors: HASSAN Y. E. , MACHI K. E.
Published: October 2008

For the rectangular strain rosette, expressions are developed for the percentage errors in the principal stresses as a function of the indicated strain readings. The critical range is identified and illustrated by curves using convenient parameters.
The X‐ray measurement of axial stress on cylindrical curved surfaces
Authors: DOIG P. , FLEWITT P. E. J.
Published: October 2008

A theoretical analysis, which corrects for the geometrical effect of specimen curvature on the angular position of diffracted X‐ray peaks recorded using the diffractometer method, has been derived. The analysis has been used to correct the diffraction angles measured using the diffractometer method for the X‐ray measurement of longitudinal stress on cylindrically curved surfaces. Residual stress versus depth profiles on a semicircular, machined keyway in an L.P. turbine disc and the residual stress distribution around a shot‐peened, L.P. turbine blade, ‘fir‐tree’, notch root, both before and after fatigue loading, have been measured.
Stress trajectories and stress contours in tapered beams
Authors: ALI S. M. J. , SARNA S. I.
Published: October 2008

This paper deals with the study of stresses in tapered beams. Stress trajectories and stress contours have been plotted for rectangular cantilever beam with horizontal top face and linear taper at the bottom face. Further research work is planned for different types of tapers (e.g. sinusoidal, parabolic) of the bottom face of a tapered beam.
Protection of strain gauges for long‐term stability
Authors: WELSH R. L. , DODD P.
Published: October 2008

A strain gauge encapsulation and protection system is described which ensures the long term stability of resistance strain gauges. Protected gauges have been subjected to normal outdoor conditions for a period of 2 years together with over 40 temperature cycles to 60°C and 215 strain cycles to 800 micro‐strain. Zero shift has not exceeded 40 microstrain.
An investigation of the dynamic and static stresses in universal bearing H‐piles
Authors: FARID M. U.
Published: October 2008

As part of continuing research on steel bearing piles, an investigation was carried out by British Steel Corporation in an attempt to gather data which will illuminate the areas of contention for limiting stress levels to be raised, thereby allowing economies to be made and customers' confidence to be increased in selecting steel bearing piles for a particular application.

To assess the characteristics of dynamic and static loading, a strain gauge measurement technique was used. Blow by blow stress analyses were carried out. In total 700 blows were examined. The full record of 700 blows and static observations can be obtained from The We/ding Research Department, of BSC's Teeside Laboratories, Middlesbrough.

The results reveal that during the course of driving the pile through hard strata, the impact stresses were 0.6 to 0.7 times the minimum yield stress, at the last blow. These impulsive stresses had no discernable effect on the structure of the piles. Results obtained suggest that considerable increase in design stresses might safely be adopted for steel bearing piles. One of the aims of this long term research is to produce a dynamic testing system which gives more accurate results than can be obtained from traditional methods.
technical note: Strain gauge slip ring circuits
Authors: GALL M. H. W.
Published: October 2008

This note describes practical uses of high quality slip rings for strain gauge measurements on rotating machinery. The advantages and disadvantages of various circuits are discussed and recommendations made for the best performance. Consideration is given to the most efficient use of the number of slip rings in a given system for the maximum data which can be obtained avoiding errors caused by slip ring noise. Other parameters which are considered are: the voltage applied to the bridge; the number of rings used to deliver power to the strain gauges and the gauge resistance. Some practical information on slip ring noise, life and cross talk and how to reduce it in the Chevron Bridge Circuit is also discussed.
A three dimensional photoelastic study of the stress distributions in double helical epicyclic gears
Authors: ALLISON I. M. , HEARN E. J.
Published: October 2008

This paper reports on part of a research programme which was carried out using two‐ and three‐dimensional photoelastic model techniques in order to analyse the stress distributions in a double‐helical epicyclic gear design incorporating typical features of production gear units.

The paper describes the testing of two three‐dimensional models, one subjected to torque loading, i.e. tooth forces; the other to combined rotational and torque loading. Note is made of some of the problems inherent in the design and loading of complex models such as those used in the tests and of the solutions developed to overcome the difficulties.

Attention is devoted to the analysis of contact loads and load distribution, maximum sub‐surface stresses, maximum root fillet bending stresses and the geometry of the lines of contact. General conclusions are drawn and an indication given of the subsequent extensive two‐dimensional test programme which was carried out.
Optimised inner boundary shapes in circular rings under diametral compression
Authors: DURELLI A. J. , RAJAIAH K.
Published: October 2008

Using a method developed by the authors, the configuration of the inside boundary of circular rings, subjected to diametral compression, has been optimised, keeping cleared the space enclosed by the original circular inside boundary. The range of diameters studied was 0.33ID/OD0.7. In comparison with circular rings of the same ID/OD, the stress concentrations have been reduced by about 30%, the weight has been reduced by about 10% and coefficients of efficiency of about 0–96 have been attained. The maximum values of compressive and tensile stresses on the edge of the hole, are approximately equal, there are practically no gradients of stress along the edge of the hole, and sharp corners exhibit zero stress. The geometries for each ID/OD design are given in detail.