bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new method of calibrating strain release coefficients in measuring welding stresses
Authors: Yasheng Wang , Lanlin Huang 
Published: October 2008

AbstractThe 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

AbstractModel 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

AbstractDuring 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

AbstractEvolution 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 interfacial fracture parameters using coherent gradient sensing (CGS)
Authors: Tippur Hareesh V. , Xu Li Ming 
Published: October 2008

AbstractAn 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

AbstractGeometric 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

AbstractA 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

AbstractWhile 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

AbstractIn 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

AbstractIn 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

AbstractAn 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.
A hybrid approach to the compliance testing of training shoes
Authors: Walker Colin 
Published: October 2008

AbstractThere is, as yet, no totally rational method for testing training shoes. The situation is complicated by the coupling that exists between the physical characteristics of the shoes and the biomechanical response to them. This paper sets out to establish a basis for the physical aspects of testing, and shows how the biomechanical response may be integrated into a suitable model. The basic assessment of the compliance properties of training shoes was carried out by the measurement of load‐deflection curves. The analysis of these curves was based on the McMahon/Green two mass, two spring model of limb‐ground interaction, which defines the tangent modulus of the load‐deflection curve as the relevant quality parameter. For a selection of 30 shoe types, the load‐deflection curves were analysed to show how a systematic approach may be developed to understanding the variances in the shoe characteristics.It has also been shown how these findings may in part explain why running shoes which have apparently widely differing load‐deflection characteristics have been found to perform rather similarly insofar as the measured level of ground reaction is concerned.
Shear stress distribution on a solid circular plate embedded in an elastic halfspace
Authors: Antony S. Joseph 
Published: October 2008

AbstractThe present investigation deals with the analysis of an axisymmetrically loaded elastic halfspace containing a solid circular plate. The elastic halfspace and the embedded plate has been idealised together as a layered system. Layered theory has been used to determine the shear stress distribution on the embedded plate. Results have been presented for the shear stress distribution on the embedded plate for different values of the relative rigidity parameter.
Evaluation of stress intensity factor under pure shear stress in orthotropic material
Authors: Shimamoto A. , Umezaki E. 
Published: October 2008

AbstractVarious types of composite materials are currently being developed and used for automobiles, airplanes, ships and other structures in response to required service conditions which are getting increasingly more severe. Of growing importance under such circumstances is the study of stress analysis and fracture mechanics for these composite material structures. Particularly, the primary concern in design of structures and machines should be the initiation of cracks due to excessive deformation, delamination in material or other material defects. In evaluating safety, it is indispensable from the structural design point of view that K value should be known by an analysis conducted in advance. In this study, stress intensity factor (mode II) under a pure shear stress was obtained using the photoelastic method and caustic method and applying an isotropic material and orthotropic material (copper fibre epoxy composite (CFEC) developed by the authors), each containing the crack. Results were compared with theoretical values. As a result, this method was found useful and the effect of the direction of the primary axis of this material on the stress intensity factor was clarified.
Laminated beams subjected to transverse load
Authors: Allison I.M. 
Published: October 2008

AbstractA simple elastic solution has been developed for predicting the shear stress distribution in a laminated beam subjected to a variety of transverse loading conditions. Photoelastic tests on composite models involving a single bonding layer have been used to validate the theory, and also to comment upon the significance of these results in interpreting the interlaminar shear strength and bending modulus of the simplest form of laminated strip.
Experimental analysis of acrylic models
Authors: Paloto J.C. , Ortega N.F. 
Published: October 2008

AbstractStrain gauge application has been used to study the mechanical behaviour of shell models. Application has been made directly to acrylic devices designed by means of the homeostatic model technique. The testing procedure of one such model made with the aim of assessing the anticipated membrane status is detailed. This has resulted in an interesting experience of strain gauge application to this type of material.
Optically enhanced tiling (OET) in digital fringe pattern analysis
Authors: Ramesh K. , Sreedhar D. 
Published: October 2008

AbstractIn digital fringe pattern analysis information is usually lost in high fringe density zones due to digitisation and quantisation errors. A generic approach namely optically enhanced tiling (OET) is presented to construct a composite picture from multiple optically zoomed images. The procedure is explained with the help of the problem of data acquisition in digital photoelasticity using phase shifting technique.
Measurement of residual stresses in a multi‐layer explosive welded joint with successive milling technique
Authors: Yasheng Wang , Hongneng Cai , Ninxu Ma 
Published: October 2008

AbstractIn the multi‐layer welded joint of titanium‐tantalum (Ti‐5Ta/Ti‐5Ta/Ta/substrate of stainless steel (SUS304) the second layer of plate Ti‐5Ta is 4mm thick, and the third plate Ta is only 1 mm thick. It is almost impossible to measure the stresses near the weld with cutting strip technique. Using a successive milling technique the inplane elastic strain releases normal to the thickness direction are measured. With the finite element method (FEM) inherent strain distribution along thickness z‐direction is evaluated according to the elastic strain releases. Subsequently, assuming that the inherent strains (plastic strains resulting from the welding process) are the initial strains of the FEM analysis for the welded residual stresses, these are used further to evaluate the residual stress distributions along the thickness z‐direction in the multi‐layer explosive welding joint.
Use of multiple loads to extract continuous isoclinic fringes by phase shifting technique
Authors: Mangal S. K. , Ramesh K. 
Published: October 2008

AbstractUsing a monochromatic light source for illumination, a new approach is proposed which uses two different loads to get continuous isoclinic fringes. A new set of optical arrangements in a plane polariscope setup is proposed for this purpose. The intensity equations are obtained by Jones calculus. The methodology is verified for the problem of a disc under diametral compression.
Error analysis and method of accuracy evaluation of strain gauge factor testing apparatus based on pure bending moment beams
Authors: Zubin Deng 
Published: October 2008

AbstractFor the appraisal of accuracy of strain gauge factor testing apparatus based on pure bending moment beams, the common means adopted since the 1960s and still in use internationally today are by application of the strain definition to measure directly the strain on the calibration beam surfaces. However, because of the imperfect measuring principle and inadequate resolution and accuracy of instruments available, etc., this problem has not been solved satisfactorily. This paper proposes a unique way by introducing two new concepts, i.e. the shape errors of the cylindrical surfaces and deflection errors of the bent calibration beam, in accordance with the features of the forces acting on the beam, and the geometric shape and dimensions of the beam in operation, to analyse and classify the various accidental and systematic errors involved. Through the two concepts, the task of appraisal of accuracy is simplified as the appraisal of the cylindricality of the cylindrical surfaces of the bent calibration beam and the appraisal of the three main parameters in the strain formula.
The Donostia method for the stress measurements in architectural heritage
Authors: Barrallo J. , Zulueta A. , Beitia S. Sánchez 
Published: October 2008

AbstractWhen structural damage appears in architecture, as in civil engineering, one of the first things to do is to analyse the level of stresses supported by the structural elements of the building. In most of the cases, the deduction of these stresses is carried out by means of one verification of the “design loads”, using analytic methods based (or not) on standardised computer assisted applications. Nowadays, there is not one experimental method close enough to deduce the loads really supported by the structural elements. This article deals precisely about the resolution of this problem by means of the hole drilling technique applied on stone constructions as this is very common in architectural heritage. The particular use of the hole drilling technique in architectural heritage is named Donostia method by the authors, and allows both the deduction of the principal stress values and their directions. This is a very important aspect when the structural damages are generated by anomalous loads.
Biological strain/stress sensing power in plants and modelling mechanisms
Authors: Nogata Fumio 
Published: October 2008

AbstractThis paper describes a cell based mechanosensing power and adapting modelling mechanisms found in plants. Biological structures consist of mechanical load carriers, which are strongly optimised in terms of mechanical strength and minimum mass. It is shown that bamboo structures are designed to have uniform stresses at all positions, applying various sizes of bamboo fibre at the optimal locations. As a significant biological design system, a biological sensing power for detecting the strain/stress induced by external loads can be accepted. The mechanosensing system can be regarded as that in which live cells detect the external mechanical strain/stress as biological electric signals generated by the motions of various ions throughout and/or into the channels of the cell membrane. The modelling mechanism is a cell based mechanosensor that depends on the kind of plant. Three types for detecting the mechanical strain/stress (tension sensitive, compression sensitive, and tension and compression sensitive types) are investigated. Changes in electrical signals at the local portion of a plant body due to the mechanical deformation of cell membranes, affect the modelling of a plant's tissue to fit external mechanical environments.
The hole drilling method in photoelasticity ‐application of an optimisation approach
Authors: Cárdenas‐García Jaime F. 
Published: October 2008

AbstractThis paper presents a least squares inverse problem solution for the case of photoelastic fringes around a hole in a biaxially loaded plate for two problems. Problem 1 relates to an infinite plate in which the circular hole is drilled first and then the loads are applied. Problem 2 is the residual stress problem in which the hole is drilled after the biaxial load is applied to the infinite plate. This hybrid experimental numerical approach permits utilisation of as many points of information as desired, away from the edge of the hole and the axes of symmetry. Also, no a priori knowledge is needed as to the orientation of the principal axes of symmetry. Its implementation, using simulated photoelastic fringes, yields accurate predictions of the magnitude and orientation of the far field stresses.
Leak detection in steam pipework
Authors: Lyon R. , Holt A. , Wilson B. 
Published: October 2008

AbstractA large number of power stations worldwide contain steam pipework where welded joints can be susceptible to circumferential cracking close to or in the heat affected zone between the weld metal and the parent material. On occasions, cracks have grown significantly around the circumference of the welds and have penetrated through the pipework wall to produce small leaks. Although these leaks were detected before significant damage could occur, there is concern that violent failures could occur from undetected cracks.At present the problem is contained by conducting rigorous but selective NDT at each shutdown on a representative sample of the critical welds. However, numbers of steam leaks have been successfully reduced, but it has not proved possible to eliminate them completely. Consequently, there remains a need to detect, and respond to those leaks which do occur as quickly as possible.A programme of work was commissioned to investigate leak detection systems with the aim of devising a suitable system for power station use.