bluuebunny/crossref_metadata_2025 huggingface dataset:
Design analysis of an automatic door closing mechanism
Authors: BRETTELL R. , KORABO Z. T. , HEARN E. J. , HAWKLEY W. T.
Published: October 2008

This paper summarises the procedures adopted for the re‐design of a small link in an automatic door closing mechanism. The design analysis consists of the application of simple materials testing techniques and unsophisticated stress analysis methods, the latter being used to survey a quite complicated loading cycle. No revolutionary procedures or ideas are involved; hopefully, however, the paper will give the reader an indication of the measure of success that can be achieved using simple, inexpensive procedures in an age when ultra‐expensive, high precision experimentation or theoretical analysis seem to be accepted as inevitable.
A study of the saddle stresses arising from the support of a cylindrical vessel
Authors: TOOTH ALWYN S. , WILSON JOHN D.
Published: October 2008

The design method widely used for the support of cylindrical vessels is that contained in BS 55001 which is based on the work of Zick2 published in 1951. In recent years, however, the theoretical analysis of this problem has received some attention,3–7 thus enabling the vessel stresses and displacements to be determined for supporting saddles of various degrees of flexibility. In this paper the saddle itself is examined, 1) experimentally, using photoelasticity, and 2) analytically by the shell analysis of refs5–7, together with a Finite Element approach. It is found that the theoretical approach used to determine saddle stresses is very sensitive to—

the type of finite element used for the saddle, and

the boundary assumption at the saddle base.

From a general stress analysis point of view, the paper should provide a warning to designers that the results obtained from finite element analyses always contain the above inherent problems. A comparison with the photoelastic results enables this to be studied. In particular the agreement between the theoretical and experimental approaches lends credence to the analytical approach used in refs5–7 and to the value of an optimum design approach for the vessel and its support.
Polycarbonate as a photoelastic material
Authors: BLAKEMORE R. H. , MARSDEN B.
Published: October 2008

The use of commercial grade polycarbonate for photoelastic models is evaluated and hints given on methods of annealing, machining, stress freezing and preparation of slices for viewing.
Abstracts
Authors: Srinath L. S. , Keshavan S. Y.
Published: October 2008

A semidestructive method for three dimensional photoelasticity

Steady state strains in power transmitting flat belts made of composite material

The application of optical fibres as witness devices for the detection of plastic strain and cracking
The use of strain gauges to determine the principal axes of composite beams of unsymmetrical section
Authors: LAKIN D. F.
Published: October 2008

Strain gauges were used to obtain experimentally the principal axes of two composite beams. The method shown is easy to use and can give results which agree closely with calculated values, and may be applied to complex composite section beams.
Reflecting grid method for curvature and twist
Authors: SUBRAMAMAN G. , ARUNAGIRI R.
Published: October 2008

The optical strain of uniform grid spacings reflected by bent beams and plates is examined for curvature and twist information in the Rieder and Ritter set‐up.
A portable electrochemical machining surface preparation system for use in the field of residual stress measurement
Authors: CHADWICK F. J.
Published: October 2008

Strain gauge residual stress measuring techniques require a smooth site surface for optimum bond performance. Mechanical metal removal techniques are generally used for surface preparation, although these may induce operator dependent residual stress which distorts the original stress distribution. The problem becomes more significant if subsurface conditions are to be evaluated by removing material, especially when hard, tough or strongly work‐hardening alloys are being investigated. To avoid the errors caused by surface preparation, the operator independent metal removal alternatives adopted have been electrolytic polishing and chemical etching. However, these methods have slow removal rates and can be hazardous to health, factors which limit their general use for residual stress measurement surveys.
Two matrix transformations for the passage of polarised light through a stressed birefringent medium
Authors: KESHAVAN F.
Published: October 2008

The passage of polarised light through a birefringent slice is dealt with using two simple matrix methods in this paper. These methods enable mechanical transformation procedures when one encounters a series of birefringent slices. The applicability of these methods is shown using classical polariscope set‐ups used in photoelastic analysis.
Determination of one principal stress
Authors: TARRAN Fausto C.
Published: October 2008

A practical and economical way to determine, experimentally, one of the principal stresses is presented. If the principal directions are known it suffices only one strain gauge, in each point of measurement, to determine this principal stress.
Rayleigh wave interaction with inhomogeneities—Part 1: Near surface cavity and inclusion
Authors: Rossmanith H. P. , Dally J. W.
Published: October 2008

The interaction of a Rayleigh pulse with a circular cavity and circular inclusion has been examined employing dynamic photoelasticity. The explosively generated R‐pulse travels along the free boundary and is trapped in the ligament between the cavity and the free boundary with little energy propagating around the cavity. For cavities and inclusions at shallow depth below the free surface failure of the ligament occurs and most of the energy associated with the incident R‐wave is converted by diffraction into body and surface waves. The existence of a shadow zone on the downstream side of the circular cavity provides a means of identifying the location of the cavity which is nearly tangent to the surface by e.g. ultrasonic inspection.
The design of a multi‐purpose multi‐component strain gauge dynamometer
Authors: Millward A. , Rossiter J.
Published: October 2008

The design, construction and calibration of a multi‐purpose multi‐component strain gauge dynamometer is described. The dynamometer was constructed for use with a free surface water channel, which can also be used as a water tunnel or a cavitation tunnel. In this experimental facility, the large speed range available (0·03 to 6·1 m/s) and the variety of projects encountered require the measurement of a wide range of loads in several different configurations. The dynamometer system has been based on a unit block concept so that the blocks can be assembled into a suitable configuration and complexity of components to suit each particular problem.

The basic design concept is described together with the calibration results and the magnitude of the interactions. It is concluded that the overall accuracy of the dynamometer blocks and the absence of interaction coupled with the versatility of the system confirm the choice of the original design.
An adaptation of an auto‐collimator for television use
Authors: COUTTS J. A. , HENEGHAN P. J.
Published: October 2008

An auto‐collimator as the basis of a measurement system has virtues, but continuous use can cause eyestrain. This note describes the modification of an auto‐collimator for a Tuckerman extensometer to television use. It was found that eyestrain was eliminated, setting up became much more rapid, and that remote measurement became possible.
Use of the Southwell method to predict buckling strengths of stringer stiffened cylindrical shells
Authors: Foster C. G. , Tennyson R. C.
Published: October 2008

This paper presents the results of some tests that were conducted on stringer stiffened epoxy cylindrical shells. The object of the investigation was to determine if the Southwell technique for estimating buckling loads could reasonably be used for the nonlinear collapse of cylindrical shells. The results showed that the technique provides a useful estimate of the buckling load provided care is taken in interpreting the results. In some instances the estimate is likely to be greater than the actual load. Where two buckling modes are encountered at the same time the Southwell technique appears to predict the critical load associated with either mode depending on the deflection parameter being measured as well as on the interpretation of the results.
A simple technique for installing strain gauges on cylindrical surfaces
Authors: Singh Sadhu
Published: October 2008

In this paper a simple technique for the installation of strain gauges on circular and conical cylindrical surfaces has been described. This technique may be adopted in an experimental stress analysis laboratory where sophisticated equipment is not available.
Reduction of static strain for increased life of transmission line conductors
Authors: GOPALAN T. V. , GIRISH S. , RAMACHANDRAN N.
Published: October 2008

Fatigue failures of transmission line conductors are known to occur close to the suspension clamps. The causes of such failures are known to be due to high static stresses combined with dynamic stresses resulting from vibration. The overall stress in the aluminium strands of a conductor could be limited by reducing the static bending stress near the clamps. Passive protective devices such as neoprene lining, damping shims introduced in the suspension clamps would bring down the stress level, thereby increasing the service life of conductors. Results of tests conducted on a laboratory span are brought out in this paper. The experimental results reveal that neoprene lining and damping shims introduced in the suspension clamp would be very effective in bringing down the static bending stress and thus the overall stress level.
Developments in a least squares asymptotic analysis of isochromatic data from stress concentration regions in plane problems
Authors: Thompson J. C. , Negus K. J.
Published: October 2008

A complete separation of stresses throughout the entire stress concentration region near notches in plane, isotropic, linearly elastic plates is achieved using only isochromatic (difference of principal stresses) data. These data, which are obtained easily by conventional photoelastic techniques, are analysed by a non‐linear least squares technique based upon previously derived equations describing the asymptotic character of the rapidly varying stress field near the root of the notch. This paper demonstrates that isochromatic data of typical experimental accuracy from relatively few, arbitrarily located data points within the highly stressed region is sufficient to accurately predict the entire stress field, including location and magnitude of critical stress(es).
Measurement of Poisson's ratio through the elastic‐plastic transition
Authors: MacKenzie P. , McKelvie J. , McDonach A. , Walker C. A.
Published: October 2008

Poisson's ratio has been measured in solution annealed stainless steel type 316, under elastic and plastic deformation, using Moire interferometry. The aim of the study was to evaluate the validity of expressions for calculating the shift in the value of Poisson's ratio, from its theoretical elastic value to its plastic value, as a function of strain.
Measurement of acoustic velocity fields
Authors: Greated C. A.
Published: October 2008

A laser Doppler system is described using photon correlation signal analysis with a microcomputer control, which can be used to measure velocities in sound waves. The free field infront of a loudspeaker has been measured to show both spatial and temporal variations. Comparisons with velocities predicted from loud level recordings show close agreement.
Strain measurement standards—an outline
Authors: Mackinnon J. A.
Published: October 2008

Strain measurement techniques are being used more frequently today to check that manufactured components are at a safe stress level in service. Designers are also requiring strain gauge tests on prototypes to confirm that the theoretical calculations are realistic and designs are economic.

Against this background the measurement engineer finds himself under pressure to produce test results quickly and sometimes to justify them. Strain measurement standards would have an important role in convincing customers that tests have been carried out in an approved manner and could be the measurement engineer's defence in the case of disputed results.

A suggested range of standards and codes of practice is described, from the anticipated BSI Standard on Strain Gauge Calibration to a proposed standard on strain gauge application and possible specifications on instrumentation for static and dynamic measurement. The need for strain measurement technician training and possible participationin the National Testing Laboratory Accreditation Scheme, NATLAS, is also discussed.
BSSM Measurement Lecture 1986 Measurement in engineering—a gas industry view
Authors: Mercer W. L.
Published: October 2008

Without reliable measurement, engineering as we know it would not be possible. Our lives would be totally different as a result. The gas industry in the UK is no exception. As a major supplier of energy, it depends on measurement in many forms over a wide range of applications. Some examples are described covering early forms of gas metering to new developments in the rapidly expanding field of optics.
Recent developments achieved in China about the centre hole relaxation technique for residual stress measurement
Authors: Hu Chun‐Nong
Published: October 2008

The paper introduces recent developments achieved in China regarding the centre hole relaxation technique for residual stress measurement. A special device developed by the author for the small blind hole drilling and measuring is described. Some examples of application of this method by using this special device are given. They include stress measurement of:

Stiffened top flange of the test section of a railway steel box girder bridge.

The butt weld joints of the ‘15 MnVNi’ alloy steel thick plates.

The welded side frames of a diesel locomotive.
A technique for dynamic tensile testing of metals
Authors: Al‐Mousawi M. M. , Deans W. F.
Published: October 2008

A technique is described for obtaining full dynamic stress/strain curves in tension up to strain rates of 100s‐1. In conjunction with a high speed servo‐hydraulic machine, a low inertia extensometer has been developed to facilitate measurement of specimen tensile strain up to fracture.

The benefits of the technique are highlighted in relation to currently available methods for dynamic stress/strain measurement.
A prototype for a resistive extensometer as a strain measuring standard
Authors: Bergqvist B. , Scherling G.
Published: October 2008

The design, handling and calibration of a prototype to a resistive extensometer with 10 mm measuring length is described.

It stands on the test specimen via pins with conical tips. These end in hard metal spherical calottes with 16 micron nose radius. The manufacturing and maintenance of these tips was described earlier.

The extensometer is calibrated on a bending beam to 1 mm/m strain, using the loading and deflection equipment developed at the FFA and described earlier.

The total extensometer inaccuracy, i.e. the sum of estimated systematic errors and random errors, the latter expressed as the 2σ confidence interval about the mean, is about 400 × 10‐4%, for 60 reproduced calibration tests.

With the extensometer, it was shown that the beam, which was machined and hardened from an alloy with 1.4% Cr and 1.4% Ni and has a moderate hardness of Hv 430, does not show any kind of inhomogeneity in Young's modulus, within the resolution of the indicator.

Therefore, the extensometer is suitable for the determination of bonded resistance gauge factors, even if a total error of only ±0.1% is required. The prototype described can therefore be used as a strain measuring standard.
A data acquisition and real time processing system for field use—dynamic strain indicator
Authors: Zheng Dou
Published: October 2008

A microprocessor based data acquisition and real time processing system used for in‐situ agricultural machinery experimentation is introduced in this paper.

The devlopment, principle and error of the system are discussed, and some practical trials are related.
Highlights on some reflections on characteristic angle, light intensity and their correlation to wavelength in three dimensional photoelastic media
Authors: Issa Sameh Salah
Published: October 2008

The minimum normalised light intensity In is introduced as a reliable characteristic parameter, in three dimensional photoelasticity, whose measurement is rather comfortable. Spectral, stress components, angle of divergence of the stress components, and material dependence of In is investigated. Limits of a cited method are pointed out. Some misunderstandings that took place in Ref. (1) are highlighted. The basic concepts of two methods in integrated photoelasticity are compared.
Direct pneumatic pressure in a clamping technique during strain gauge bonding
Authors: Sell P.J.
Published: October 2008

A technique is described for the clamping of metallic foil strain gauges during epoxy adhesion bonding to non ‐porous surfaces. Following application of the uncured adhesive, the gauge is conformed to the surface using self‐adhesive tape and the workpiece placed in a pressurised environment for the duration of cure. The pnematically derived clamping pressure is transmitted directly to the glue line, and is equal to the pressure within the containment vessel. Since the clamping pressure is both uniform over the strain gauge area, and readily reproducible between installations, it is possible to produce consistent gauge performance. The technique may offer time and cost advantages over classical clamping methods where gauges are installed on small, intricate, or batch components in stress analysis and transducer applications.
Europe 1992 ‐ Standards, testing and certification
Authors: Chalmers G F
Published: October 2008

Standards, testing and certification are major topics of discussion in relation to the European single market in 1992. The British Society for Strain Measurement has taken initiatives since 1977, to try to raise the standards of validation of competence in testing and analysis particularly in the areas of stress and strain measurement and analysis. This paper sets out some of the current thinking of the BSSM, in an attempt to obtain wider support for and participation in, what it considered to be one of the vital approaches to improved product quality, performance, safety and reliability.
An analysis of the transient stresses in a heavy duty switching unit
Authors: Evans W. T. , Smith S. J.
Published: October 2008

An analysis has been made of the transient bending and shear stresses set up in the drive shaft of an 11 W ring main switch unit manufactured by South Wales Switchgear Ltd. The analysis compares theoretical bending and shear stress plots along the main shaft with experimental values obtained from electrical resistance strain gauges.
Efficient data acquisition for engineers
Authors: Kimber T.
Published: October 2008

A method of simple modular data acquisition is described. The approach is currently used by engineers for a wide variety of applications. It is particularly useful for engineers who have a limited knowledge of computer programming.
Early days of the resistance strain gauge
Authors: Gall M W
Published: October 2008

The earliest developments in the use of electrical strain gauges as a means of quantifying the measurement of stress in materials are recalled by the author, whose own involvement was associated with the early developments in the mechanised production of strain gauges. The manufacture of batch quantitities is vividly recounted following the realisation that strain gauges would lend themselves to commercial exploitation.
Lubricant effects on strain fields of seven wire strands subjected to tensile load
Authors: Cappa P.
Published: October 2008

As a part of an extensive analysis on strand behaviour the lubricant effect in strain fields was examined. The strains were measured by using electrical resistance strain gauges. The results obtained, by loading the unlubricated and lubricated sample both statically and quasi‐statically, showed relevant effects caused by different contact loads developed among the wires. By examining the strains measured during the severing of one helical wire the inapplicability to the strands of one Italian regulation relative to wire ropes, was also confirmed.
Calibration of the thermoelastic stress analysis technique under sinusoidal and random loading conditions
Authors: Harwood N. , Cummings W.M.
Published: October 2008

For the past five years the National Engineering Laboratory (NEL) has been engaged in a research programme investigating the applications of thermoelastic stress analysis to engineering structures. This paper discusses the use of a uniformly stressed component for the calibration of SPATE (Stress Pattern Analysis by Thermal Emission). Experimental results for sinusoidal loading on a carbon steel are compared with a theoretical prediction based upon material properties and instrument characteristics. A calibration technique which is suitable for the measurement of quantitative stresses under random loading, including modal behaviour, is also described.
Stress dependence of specific heat: observations on the TERSA technique
Authors: Dunn S A , Sparrow J G
Published: October 2008

Recently a new method of residual stress measurement, TERSA, was described1and it was suggested that there was a contribution to the effects reported from the stress dependence of specific heat. In this paper, experimental and theoretical evidence is presented demonstrating that the magnitude of the change of specific heat with stress is too small to make a significant contribution to the change in temperature resulting from a stress increment applied to a laser irradiated object.
The examination of heat effects on bond degradation in reinforced concrete using acoustic emission
Authors: Royles R. , Khan M.R.
Published: October 2008

Experimental tests were carried out on pull‐out concrete speciments with 8 mm dia. tor steel bars to examine the extent of deterioration of bond at the interface of steel and concrete afer exposure of the speciments up to 800°C furnace temperature. The bond stress‐slip behaviour was examined and acoustic emission monitored simiultaneously. The bond stress‐emission and slip‐emission were compared and correlated with the bond stress‐slip behaviour for speciments subjected to diferent levels of temperature both in the heated as well as the residual conditions. Random samples of waveforms of the emission for specific levels of temperature were compared with respect to the amplitude and time period of the pulses as well as the occurrence of reflections etc. Consequently attempts were made to utilise acoustic emission behaviour in establishing the trend of bond degradation in reinforced concrete by heat effects. The control of variable was the level of temperature exposure.
The fatigue of strain gauges ‐ a user's view
Authors: Halford Chris F
Published: October 2008

The information needed by the strain measurement engineering concerning the fatigue of strain gauge installations is discussed, and compared with that readily available. It is suggested that far more extensive and detailed information is needed and should be made readily available.
Simulated seismic loading on reinforced concrete beam/column connections
Authors: Scott R H , Gill P A T
Published: October 2008

Laboratory tests to investigate the seismic behaviour of five reinforced concrete external beamlcolumn connection specimens, by subjecting the beams to a series of slow load reversals, are described. The first three tests were undertaken as an extension of a static (non‐seismic) test programme and were primarily carried out for the purposes of rig development. The two further test specimens contained additional links in the connection zone to make them representative of current seismic practice in the U.S.A. These two specimens were subjected to a series of slow load reversals specifically intended to simulate seismic effects.

With the first three specimens, complete destruction of the connection zone was achieved after only four or five cycles; the last two specimens withstood ten and twelve cycles respectively. One of these latter specimens failed due to the development of a plastic hinge at the beaml column junction, the other by plastic hinges forming in the column above and below the beam. Detailed information regarding the form of the reinforcement strain distributions developed during these tests is presented, data being obtained using reinforcement internally strain gauged with electric resistance strain gauges. Each specimen contained around 230 such gauges.
A physiotherapy aid using strain measurement techniques
Authors: Rushton D H
Published: October 2008

This paper describes the use of strain measurement interfaced through a computer graphic animated display for the purpose of obtaining from a child patient accurate data of physical disability. The animated display is also used as a means of retaining and stimulating interest in the child during the series of exercises that this interfaced system would be capable of, monitoring and recording the results at the same time.
Computer aided analysis of strain rosette data
Authors: Singh Sadhu
Published: October 2008

In this paper a computer program has been developed for analysing the strain gauge rosettes by considering the transverse sensitivity of all gauges. The program is capable of calculating principal strains, maximum shear strain, principal stresses, maximum shear stress and principal directions from the data obtained by using strain gauge rosettes of various configurations. The gauge factor and transverse sensitivity of all gauges in the rosette must be the same.
Influence of measurement and evaluation parameters on stress distributions investigated by X‐rays
Authors: Wern H.
Published: October 2008

The complete triaxial X‐ray strain or stress analysis including gradients requires a physical description of the beam path through the superficial layer of the material for both the conventional ω and Ψ goniometer. Within this description, a theory has been developed for plane, cylindrical, spherical or any other convex or concave specimen topography which can be described by two different radii. All crystal structures are supported. Measurements and calculations are controlled by the independent in‐situ determination of Poisson's ratio and the stress free lattice spacing. The physical boundary conditions are verified or can be postulated depending on the measurement quality. A complete internal strain and stress field analysis is discussed in terms of the ‘X‐ray integral method’ on steel specimens of 100 Cr‐6 (ASTM: A 295, BS: 97012), Al2O3 ceramics using conventional X‐ray diffractometry and on NiO layers on a metal substrate by the use of synchrotron radiation and parallel beam optics.
Procedures for analysis of strain transfer in the acetabular region in vitro
Authors: McNamara J , Slemon D , O'Donnell P , Zeng Z P , Warfield V , Jarvis J , Little E
Published: October 2008

The failure of acetabular cups via loosening, migration or fracture is partially related to the stress distribution existing in the acetabular region. The complexity of the investigation of these stresses demands the application of a variety of model testing techniques involving combined embedded strain gauging, finite element analysis, transmission and reflective photoelasticity and crack propagation studies. The application of these procedures are described and the difficulties of obtaining representative loadings and restraints are commented upon.
Contour measurement using retrographic imaging
Authors: Montrose C. , North W.P.T.
Published: October 2008

A new experimental method called retrographic imaging has been developed which uses retroreflected light for visualising minute irregularities in reflective opaque surfaces. This paper provides a qualitative explanation of this phenomenon, the experimental setup required for such imaging, and describes an experiment which was devised to determine how this type of imaging can be correlated to actual surface topography. Results indicate that grey level intensity is proportional to an average between the surface contour and its rate of change of slope.
A new method for measurement of three dimensional residual stresses in a multi‐pass butt welded joint
Authors: Huaipu Zhao
Published: October 2008

In this paper, a new method for the measurement of three dimensional residual stresses in a multi‐pass butt welded joint is presented. The method involves the measurement of strain changes at a through hole surface as a coupon of material with the hole is separated from the body of interest and split. The finite element calculations are used to relate the strain changes at the measurenent points to the initial residual stresses at the hole location. The accuracy of the method is demonstrated by using it to measure a known stress field in a bent beam. The method has been used to measure the through thickness distribution of three dimensional residual stresses in a multi‐pass butt welded joint. It could also be applied to the measurement of residual stresses in other welded joints.
The deformation mechanics of interlock tubes
Authors: Chen Z. , Reuben R. L. , Owen D. G.
Published: October 2008

Interlock tubes are one of the key structural layers of most flexible pipes of composite construction for offshore oil and gas transmission and water injection applications. The design and manufacture of such a tube based on a good understanding of its deformation mechanics are undoubtedly of significance to the integrity and safety of flexible pipes and pipe systems. This paper describes a semi‐empirical model for the evaluation of the deformations in the critical sections of the interlock tube as it responds to the overall pipe loading and configuration. Results of a finite element analysis and radiographic tests are incorporated to verify and supplement the model.
The heating effect of electrical resistance strain gauges applied to low thermal conductivity materials
Authors: Zhang T. , Evans J. R. G. , Rees D. W. A.
Published: October 2008

Gauge heating effects were examined for the case where an electrical resistance foil gauge is bonded to a low thermal diffusivity material. These include i) the effectiveness of a temperature compensating gauge, ii) the influence on localized creep and relaxation behaviour in the material and iii) the relative order in which the bridge is energised and the testpiece loaded. Calculated temperature distributions are confirmed from experiment. This has enabled recommendations to be made for the allowable specific power corresponding to a given temperature rise in a gauge grid of known configuration.
Assessment of strain gradients affecting the performance of 3‐D strain rosettes – relevant to the analysis of cement mantle strains in total hip replacements
Authors: Tague D. Mc , Little E. G.
Published: October 2008

A large scale model analysis, using embedded strain gauges, of the strain distribution in the cement mantle surrounding a femoral prosthesis is underway. In order to predict, and so avoid, positions of locally high strain gradients in this model, a finite element and experimental analysis of a similar problem was undertaken. For this purpose, a loose fitting rectangular steel insert inside a surrounding rectangular epoxy sheath was used to model an extreme case of the torsional and bending components of hip joint load. The axial component of joint load was modelled using an axisymmetric finite element model of a tapered shaft. The finite element results were used to determine suitable positions for embedding gauges in the experimental model. Results showed that the finite element analysis failed to adequately model the close sliding fit between the steel insert and epoxy. Altering the experimental model to artificially replicate the finite element contact conditions produced good correlation in bending, with experimental strains agreeing with simple bending theory to within 6%. Satisfactory correlation under torsional loading was not obtained, but strain magnitudes were low. Predicted positions for embedding gauges give conservative results, lessening the possibility of strain gradient induced error in the large scale model test of the cement mantle and prosthesis.
The use of composite materials in vehicle mounted tanks
Authors: Butler S.
Published: October 2008

Glass reinforced polyester is used for the design of 5500 litre vehicle mounted tanks which carry a variety of liquids to farms. The main panels of the tanks are designed as flat or slightly domed membranes using a theory which depends on resistance to the membrane tension by ‘in plane’ shear within the panel. The vehicle dynamic loading can only be estimated and therefore the tanks have been developed from experience over some years. The primary problem in the design follows from the forced bending strain at the edges of the membrane panels, that is, the corners and joints of the tanks. Strain controlled testing of both the glass fibres and the GRP laminates is used to determine the acceptable limiting strain in the tanks for the operating conditions. The main panel design has not given any problems but care was essential to keep the local strain at comers and joints within the strain limit for the GRP.
Measurement of cab mounting point loads
Authors: Allison I.M. , Nurse P.
Published: October 2008

A transducer measuring three orthogonal force components has been incorporated in the flexible mountings of a lorry cab so that the dynamic response of the system is unchanged. The instrumentation used to monitor and record the mounting point forces, both during calibration of the transducers, and subsequent road trials has been described. Values of the Cartesian components measured at the front and rear cab mounting points during passage of the loaded vehicle over a simulated Australian road are presented, and the maximum values determined.
Comparison of dynamic initiation toughness measured by strain gauges and the shadow optical method
Authors: Hermann R. , MacGillivray H. J. , Dear J.P.
Published: October 2008

The deformation and fracture behaviour in dynamically loaded Charpy specimens of BS11 rail steel were studied by two different measuring techniques. The transient records obtained from straingauges were compared with results obtained simultaneously by the shadowoptical method. Good agreement was obtained when measuring and comparing the stress intensity factor K in the initial stages of deformation behaviour prior to crack initiation. During fast fracture, the shadow optical method indicated the influence of dynamic effects on crack propagation.
In‐situ stress determination used in structural assessment of concrete structures
Authors: Owens A.
Published: October 2008

Large span, post‐tensioned bridges are now regularly subjected to spot checks. Bridge assessment requires a knowledge of the design pre‐stress and of any losses that may have occurred since stressing. The assessing engineer is often faced with a lack of information, such as no detailed drawings, no confirmation that build was to design, and it is at this stage that on‐site in‐situ stress determination can be used to progress the investigation. The methods for in‐situ stress determination are based upon the measurement of strain distribution due to local stress relief and the relationship of the strain redistribution to the in‐situ stress state. The adaptation of the centre hole technique to the in‐situ stress determination in reinforcement, stressing tendons and concrete and the necessary site requirements are explained.
Deformation analysis of skew ruled surface shells by moiré interference
Authors: Huimin Xie , Shaochuan Pan
Published: October 2008

The use of thin film grids coated on surfaces is described in relation to the determination of deformations in doubly curved shells. The technique is called the coating film moiré interference method and employs a laser holographic approach.
A new method of calibrating strain release coefficients in measuring welding stresses
Authors: Yasheng Wang , Lanlin Huang
Published: October 2008

The measured values of welding residual stresses often exceed material yield strength (σy) or tensile strength (σt), in measuring welding residual stresses in the welded joints of low carbon steel or stainless steel by drilling a blind hole. It is quite evident that measured values do not represent reality. Local plastic strain caused by residual stress concentrations round the blind hole has a main effect on the measuring error of welding residual stresses. This article presents a new method of calibrating strain coefficients A and B for eliminating influence of local plastic strain. In calibrating strain release coefficients A and B, calibrating stresses applied on the specimen were increased so that material round the blind hole produced local plastic deformation, ie coefficients A and B contained a component of the plastic strain. Numerial values of coefficients A and B were classified into four grades. Every grade coefficient contained a different quantity of the plastic strain for offseting the influence of the plastic strain round the blind hole. Test results have proved that by adopting these coefficients more satisfactory values for residual stresses can be obtained in practical engineering. The measuring average error in stainless steel (1Cr18Ni9Ti) reduces from 109% to 1.52%. The measuring average error in low carbon steel reduces from 54.69% to 3.21%.
A review of joint and muscle load simulation relevant to in‐vitro stress analysis of the hip
Authors: Colgan D. , Trench P. , Slemon D. , McTague D. , Finlay J.B. , O'Donnell P. , Little E.G.
Published: October 2008

Model analysis of the hip has become an important research technique in the assessment of implant performance in Total Hip Replacements (T.H.R.). In the literature to date, however, there is an absence of suitable criteria to aid in the selection of representative joint and muscle loading conditions relevant to such analyses. Consequently, the interpretation of information regarding the loading of the hip joint varies greatly between studies. The objective of this study, therefore, is to review the procedures used to establish these forces and to outline how they may be appliedto in‐vitro modeltesting of the proximal femur and the pelvis. The muscles active at the hip joint are categorised with respect to their positions and primary actions. The magnitudes of the muscle and joint loads, as estimated by force determination studies employing in‐vitro, in‐vivo and mathematical modelling techniques, are reviewed. Applications illustrating the load simulations applied to the model analysis of an implanted Exeter femoral prosthesis and the in‐vitro testing of cementless acetabular cups are also presented. While there is reliable information regarding the joint reaction between the femur and the acetabulum, it is difficult to represent accurately the muscular loading, due to the conflicting information presented in the literature. It is possible, however, to apply this information to load simulations in a limited manner in an attempt to predict trends in behaviour which are representative of the in‐vivo situation.
An experimental analysis of the forces exerted by perioral muscles on the dental arches
Authors: Branca F.P. , Cappa P. , Mastrantonio F.
Published: October 2008

During the various oral functions, as is known, perioral muscles interact with dental tissues, gingivae and alveolar bone. Since the forces they exert during this interaction may affect teeth position, it appears very important in orthodontics to acquire means for monitoring and measuring them. Nevertheless, from an analysis of literature on this specific subject a lack of knowledge concerning the amount of load exerted by perioral muscles emerges, so that its contribution so far to teeth displacement is unknown. The aim of the present work is the “in vivo” evaluation of the actual forces applied by perioral muscles on dental arches by an automatic measurement chain carried out by means of two miniaturised load cells (full scale=9.81 N) placedon the upper incisors. Preliminary results permitted an estimation of the maximum value of the applied force range for various phonema, which proved to be in every case lower than about 1.98 N.
Evolution of the partial image velocimetry measuring technique
Authors: Gray C. , Greated C. A.
Published: October 2008

Evolution of the non‐intrusive flow measuring technique known as particle image velocimetry (PIV) is reviewed. Techniques for illuminating the flow field and recording the images are compared and the principles of image analysis outlined. Recent developments in stereoscopic and holographic PIV, application to vibration fields and fibre optic beam transmission are also discussed.
Measurement of non‐uniform residual stresses using the hole drilling method, a new integral formalism
Authors: Wern H.
Published: October 2008

A new analysis technique in combination with a finite element calculation is introduced to resolve the residual sress profile of measurements performed with the hole drilling or ring core method.
Measurement of interfacial fracture parameters using coherent gradient sensing (CGS)
Authors: Tippur Hareesh V. , Xu Li Ming
Published: October 2008

An optical interferometry called coherent gradient sensing (CGS) has been extended for mapping interface crack tip fields and for evaluating fracture parameters. The optical technique is a double grating shearing interferometer with an on line spatial filtering arrangement. The method offers real time full field measurements and can be used both in transmission made and reflection mode. The interferometer measures small angular deflections of light rays which can be further related to in plane gradients of s̀x + s̀y in transmission through elasto‐optic relations. Direct interfacial crack tip measurements in a high stiffness mismatch PMMA‐aluminium bimaterial system are performed. A variety of crack tip mode mixities are studied using asymmetric four point bend specimens subjected to different far field mechanical loads. The. complex stress intensity factors and the associated phase angles are measured from CGS patterns using an asymptotic expansion field. The measurements are compared with finite element results.
Imperfection measurement of cylinders using automated scanning with a laser displacement meter
Authors: Berry P.A. , Bridge R.Q. , Rotter J.M.
Published: October 2008

Geometric imperfections, commonly in the form of depressions at the circumferential welds, are present in most metal silo structures and can greatly reduce the structure's buckling strength. These imperfections sure close to axisymmetric in form. This paper describes the measurement system which was developed for an experimental study of this phenomena. Computer controlled steppennotors for both Hie circumferential and longitudinal travel of the measurement carriage provided a precise and repeatable traverse of the specimen. A laser displacement meter, which is capable of high speed, non‐contact measurement and has a resolution of 0.5 microns, was controlled synchronously with the steppennotors to provide a very accurate three‐dimensional measurement system. Both the initial geometrically imperfect shape and the progressive growth of deformations during loading were accurately measured.
The effect of diameter/thickness ratio on the ratchetting behaviour of pressurised plain pipework subjected to simulated seismic loading
Authors: Moreton D.N. , Yahiaoui K. , Moffat D.G. , Zehsaz M.
Published: October 2008

A series of five tests have been conducted using cylindrical specimens having mean diameter/thickness (Dm lt) ratios in the range 9≤Dm lt ≤25. The cylinders were subjected to an internal pressure (calculated as the design pressure for each cylinder) and alternating bending moments at frequencies typical of seismic events. Hoop ratchetting was recorded in all cylinders at bending moments greater than the yield moment. The moment level for the onset of ratchetting was found to be in agreement with theoretical predictions. The variations in behaviour caused by changing D/t ratios is discussed.
A hybrid experimental/computational approach to the assessment of crack growth criteria in composite laminates
Authors: Walker C.A. , Jam M.
Published: October 2008

While a number of criteria have been proposed for predicting the onset of crack growth in composite laminae, there has hitherto been no accepted method of assessing the value of alternative proposals. This study integrates the use of computational modelling, along with moiré interferometry for the quantitative mapping of near crack tip deformation fields. The moiré method was used to validate the computational model. It was then possible to use the computational model on its own to predict crack tip behaviour in more detail than could be done with the optical system alone.

This study chose one crack growth criterion ‐ the normal stress ratio ‐ to demonstrate the assessment routine. The value of the normal stress ratio (NSR) was calculated as a function of the ply angle to the loading direction. In order to obtain sensitive predictions of crack growth direction, it was desirable to proceed by analysing the crack tip behaviour down to radial distances from the crack tip of a few tens of microns. By a suitable choice of elements around the crack tip, the finite element model was able to predict values of the NSR down to a radius of 80 times10‐3mm around the crack tip.
Behaviour of pipes with a circular hole subjected to compressive loading
Authors: Hoon K.H. , Soh A.K.
Published: October 2008

In the fabrication of offshore structures, cutouts are often made on pipes to allow access to the interior of the pipes for maintenance and servicing. Thus, there is a necessity to investigate the effects of cutouts on the buckling load of pipes. Both the finite element and experimental techniques have been employed to investigate several series of pipes with and without cutouts. The results obtained were in reasonably good agreement with those obtained by the semiempirical solution.
A study on the production of 950°C moiré gratings in metal materials
Authors: Huimin Xie , Dietz Peter , Schmidt Axel , Fulong Dai
Published: October 2008

In this paper, a new method for producing high temperature gratings is put forward. With two deposited metal layers on the specimen, the oxidation resistant ability of this grating was improved, and its applications were enlarged, to cover almost all metals. The procedure for producing a grating and the controlling factors of grating quality are discussed in detail.
Automation of data acquisition in reflection photoelasticity by phaseshifting methodology
Authors: Ramesh K. , Mangal S.K.
Published: October 2008

An optical arrangement for application of the phaseshifting technique to reflection photoelasticity is presented. The intensity equations for application of phaseshifting methodology are obtained by Jones' calculus. A new portable reflection polariscope is designed to effect the optical arrangement. The use of a commercially available Handycam is shown to meet the requirement of image capturing for digital photoelastic analysis. Fringe order variations for three arbitrary lines in a circular disc under diametral compression are obtained by the new methodology and compared with theoretical predictions. The comparison is found to be good.