Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Oxford HEXameter: Laboratory High Energy X-Ray Diffractometer for Bulk Residual Stress Analysis (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 524-525 (Sept. 2006), p. 743-748 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Diffraction of penetrating radiation such as neutrons or high energy X-rays provides apowerful non-destructive method for the evaluation of residual stresses in engineering components.In particular, strain scanning using synchrotron energy-dispersive X-ray diffraction has been shownto offer a fast and highly spatially resolving measurement technique. Synchrotron beamlines providebest available instruments in terms of flux and low beam divergence, and hence spatial andmeasurement resolution and data collection rate. However, despite the rapidly growing number offacilities becoming available in Europe and across the world, access to synchrotron beamlines forroutine industrial and research use remains regulated, comparatively slow and expensive. Alaboratory high energy X-ray diffractometer for bulk residual strain evaluation (HEXameter) hasbeen developed and built at Oxford University. It uses a twin-detector setup first proposed by one ofthe authors in the energy dispersive X-ray diffraction mode and allows simultaneous determinationof macroscopic and microscopic strains in two mutually orthogonal directions that lie approximatelywithin the plane normal to the incident beam. A careful procedure for detector response calibrationis used in order to facilitate accurate determination of lattice parameters by pattern refinement. Theresults of HEXameter measurements are compared with synchrotron X-ray data for several samplese.g. made from a titanium alloy and a particulate composite with an aluminium alloy matrix.Experimental results are found to be consistent with synchrotron measurements and strain resolutionclose to 2×10-4 is routinely achieved by the new instrument
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/13/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.524-525.743.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    A Study of Residual Elastic Strain Distribution in an AZ91 Mg Alloy Bar Loaded in Four Point Bending (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 571-572 (Mar. 2008), p. 113-118 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: This paper presents a study of the residual strain field within a high pressure die cast(HPDC) AZ91 Mg alloy bar subjected to four point bending. The technique employed for this purposeis high energy synchrotron X-ray diffraction. Strain scanning using polychromatic X-ray beam allowsthe collection of multiple peak diffraction patterns and monitoring of small peak shifts as a function ofbeam position. These shifts allow collective interpretation in terms of the equivalent macroscopicresidual elastic strain. Residual elastic strain distributions were studied in the sections subjected to purebending and also in sections of contact between the sample and the rollers. These experimental resultsare compared with the predictions from a finite element analysis of contact and deformation. Goodagreement is found between the modelled and measured results. It is hoped that these results helpimproved understanding of complex deformation behaviour of thin-walled HPDC AZ91 componentsand provide useful background information for lifing assessment of such structures
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/18/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.571-572.113.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Inter-Granular Residual Stresses in Polycrystalline Aggregates: Finite Element Modelling and Diffraction Post-Processing (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 571-572 (Mar. 2008), p. 271-276 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Most models based on continuum mechanics do not account for inhomogeneities at themicro-scale. This can be achieved by considering a representative volume of material and using(poly)crystal elasto-plastic deformation theory to model the effects of grain morphology andcrystallographic orientation. In this way, the relationship between the macroscopic stress state andthe stress state at the grain level can be investigated in detail. In addition, this approach enables thedetermination of the inhomogeneous fields of plastic strain, the identification of regions of localisedplasticity (persistent slip bands), grain level shakedown, and the prediction of fatigue crackinitiation using energy dissipation at the micro-scale. Elastic anisotropy is known to promote earlieronset of yielding, and to increase the magnitude of intergranular residual stresses. The effect ofhardening behaviour of different slip systems on intergranular residual stresses is more subtle, asdiscussed in the text. The present study focuses on the analysis average intergranular residualstrains and stresses that arise within the polycrystal aggregate following the application of single orcyclic external loading. These residual strains can also be evaluated experimentally using diffractionof penetrating radiation, e.g. neutrons or high energy X-rays, allowing comparisons with the modelpredictions to be made
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/18/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.571-572.271.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Analysis of Residual Stresses Around ‘Dimpled’ Cold-Expanded Holes in Aluminium Alloy Plates (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 571-572 (Mar. 2008), p. 295-300 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A traditional approach to increasing fatigue resistance of many assemblies involves thecreation of regions of compressive residual stress. For example, riveting holes used in modernpassenger aircraft are currently subjected to cold expansion using split mandrel tools. The method isrelatively expensive and not entirely problem-free. In the present study we consider a method ofcreating residual stresses around drilled holes referred to as ‘dimpling’, that itself is a variation of anovel technique known as the StressWaveTM process. An experimental procedure is described forthe creation of localised regions of significant plastic deformation and residual stress by ‘dimpling’,allowing the production of cold-worked and residually-stressed specimens. The overall aims of thisstudy were to determine thickness-average residual stresses by two different techniques, namely,one destructive technique (Sachs boring) and one non-destructive (high energy X-ray diffraction);and to compare the results. In Sachs boring experiments the variation of strain gauge readings withincreasing diameter of the central hole was recorded. A classical elastic-ideally plastic axisymmetricmodel for plane stress conditions was used in the analysis. Energy dispersive synchrotron X-raydiffraction experiments were performed for non-destructive assessment of residual elastic strains.The two different stress evaluation techniques used in this project led to consistent results. Goodcorrelation was found between the stresses obtained from X-ray diffraction results and thosededuced from Sachs boring experiments
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/18/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.571-572.295.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Synchrotron Energy-Dispersive X-Ray Diffraction Analysis of Residual Strains around Friction Welds between Dissimilar Aluminium and Nickel Alloys (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 571-572 (Mar. 2008), p. 407-412 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Friction welding processes, such as friction stir welding (FSW) and inertia frictionwelding (IFW) are popular candidate procedures for joining engineering materials (includingdissimilar pairs) for advanced applications. The advantages of friction welding include lack of largescale material melting, ability to join dissimilar materials, and relatively low propensity to introducedefects into the weld joint. For these reasons FSW and IFW have become the subjects of a numberof studies aimed at optimising the joining operations to obtain improved joint strength and reducedistortion and residual stress. In the present study we used the diffraction of high energypolychromatic synchrotron X-rays to measure interplanar lattice spacings and deduce nominalelastic strains in friction stir welds between dissimilar aluminium alloys AA5083 and AA6082, andin coupons from inertia friction welds between dissimilar nickel-base superalloys IN718 andRR1000. Energy-dispersive diffraction profiles were collected by two detectors mounted in thehorizontal and vertical diffraction planes, providing information about lattice strains in two nearlyperpendicular directions lying almost in the plane of the plate samples mounted perpendicularly tothe incident beam. Two-dimensional maps of residual stresses in friction-welded joints wereconstructed. Apart from the 2D mapping technique, the sin2ψ method (transmission) was also usedin the case of inertia friction-welded joint between nickel alloys. Comparison between the tworesults allowed the variation of the lattice parameter with the distance from the bond line to bededuced. It was found that friction welding of two dissimilar materials with significant strengthmismatch may lead to the creation of a region of compressive stress in the vicinity of the bond line,in contrast with the behaviour observed for joints between similar materials
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/18/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.571-572.407.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Residual Stress in Laser Bent Steel Components (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 524-525 (Sept. 2006), p. 299-304 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The kinetics of plastic deformation and microstructural evolution, and the residual stress inparticular, were investigated on the steel plates (SABS 1431) bent by laser beam. The steelplates were bent by different number of laser scans and therefore, each was bent to a differentextent. The stress results obtained by x-ray diffraction (sin2ψ-method) show a highercompressive stress along the laser path than in the transverse direction. It was also found thatstress relaxation occurs during multi-scan laser forming process and most importantly, that thestress is not significantly different in comparison to the stress, which initially existed in rolledsteel plates. The metallographic analyses show that phase transformation, dynamic recovery andrecrystallization processes occur during laser forming
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/13/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.524-525.299.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Experimental/Modelling Study of Residual Stress in Al/SiC〈sub〉p〈/sub〉 Bent Bars by Synchrotron XRD and Slitting Eigenstrain Methods (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 571-572 (Mar. 2008), p. 277-282 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The aim of the study presented here was to evaluate the residual stresses present in a barof aluminium alloy 2124-T1 matrix composite (MMC) reinforced with 25vol% particulate siliconcarbide (SiCp) using X-ray diffraction and 3D profilometry (curvature measurement usingMitutoyo/Renishaw coordinate measurement machine) and comparing these results with numericalmodels of residual strain and stress profiles obtained by a simple inelastic bending model and FiniteElement Analysis (FEA). The residual strain distribution was introduced into the test piece byplastic deformation in the 4-point bending configuration. At the first stage of this study the elasticplasticbehaviour of the MMC was characterized under static and cyclic loading to obtain thematerial parameters, hardening proprieties and cyclic hysteresis loops. Subsequently, synchrotron Xraydiffraction and CMM curvature measurements were performed to deduce the residual stressprofile in the central section of the bar. The experimental data obtained from these measurementswere used in the inelastic bending and FEA simulations. The specimens were then subjected toincremental slitting using EDM (electric discharge machining) with continuous back and front facestrain gauge monitoring. The X-ray diffraction and incremental slitting results were then analysedusing direct and inverse eigenstrain methods. Residual stresses plots obtained by different methodsshow good agreement with each other
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/18/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.571-572.277.pdf
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...