scholarly journals Advances in Neutron Diffraction for Engineering Residual Stress Measurements

1999 ◽  
Vol 33 (1-4) ◽  
pp. 151-171 ◽  
Author(s):  
A. N. Ezeilo ◽  
G. A. Webster
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Measuring Method ◽  
Manufacturing Processes ◽  
Stress Measurements ◽  
Code Of Practice ◽  
Numerical Predictions ◽  
Engineering Materials ◽  
Neutron Diffraction Technique

The increasing awareness amongst engineers and designers, of the significance of residual stresses in influencing the useful lifetimes of engineering components, has resulted in more demanding expectations being placed on the methods used to obtain these stresses. The neutron diffraction technique is emerging as the most attractive measuring method as the residual stresses can usually be obtained non-destructively to depths of up to 40 mm in some common engineering materials. Although it is a relatively new technique it has been used to measure the residual stresses in a range of engineering materials introduced by a wide variety of manufacturing processes such as welding, quenching, machining, shot peening, cold hole expansion and autofrettage.In this paper the neutron diffraction technique for non-destructive residual stress measurements will be described including methods used to validate the measurements. Precautions that should be taken in order to obtain reliable measurements are outlined. Procedures being investigated in order to produce a code of practice will be presented. A representative selection of stress distributions developed by a range of manufacturing processes is examined. Some comparisons are made with strain gauge, X-ray and numerical predictions. It is shown how the results can be of benefit in engineering stress analysis.

scholarly journals Neutron diffraction measurements of weld residual stresses in three-pass slot weld (Alloy 600/82) and assessment of the measurement uncertainty

2020 ◽  
Vol 53 (5) ◽  
pp. 1181-1194 ◽  
Author(s):  
Vasileios Akrivos ◽  
Robert C. Wimpory ◽  
Michael Hofmann ◽  
Beverly Stewart ◽  
Ondrej Muransky ◽  
...  
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Weld Metal ◽  
Lattice Parameter ◽  
Alloy 600 ◽  
Data Set ◽  
Iron And Steel ◽  
Stress Measurements ◽  
The Uk

This paper describes in detail two neutron diffraction residual stress measurements, performed on the ENGIN-X neutron scattering instrument at the ISIS facility in the UK and on the SALSA instrument at the Institut Laue–Langevin in Grenoble, France. The measurements were conducted as part of the NeT Task Group 6 (TG6) international measurement round robin on an Alloy 600/82 multi-pass weldment – a slot in an Alloy 600 plate filled with three Alloy 82 weld beads, simulating a repair weld. This alloy/weld combination is considered challenging to measure, due to the large grain size and texture in the weld, and large gradients in the stress-free lattice parameter between the parent and weld metal. The basic principles of the neutron diffraction technique are introduced and issues affecting the reliability of residual stress characterization are highlighted. Two different analysis strategies are used for estimation of residual stresses from the raw data. Chemical composition studies are used to measure the mixing of parent and weld metal and highlight the steep lattice parameter gradients that arise as a consequence. The inferred residual stresses are then compared with three sets of measurements performed on the same plate by other NeT partners on E3 at the HZB in Berlin, STRESS-SPEC at the FRM II in Munich and KOWARI in Sydney. A robust Bayesian estimation average is calculated from the combined five-instrument data set, allowing reliable best estimates of the residual stress distribution in the vicinity of the weldment. The systematic uncertainties associated with the residual stress measurements are determined separately in the weld and parent materials, and compared with those in the NeT TG4 benchmark. This is a three-pass slot-welded plate fabricated from American Iron and Steel Institute AISI 316L(N) austenitic stainless steel, and is normally considered less challenging to measure using diffraction techniques than all nickel welds. The uncertainties in the stress measurements by neutron diffraction for these two weldments seem to be comparable.

Interpretation of residual stress distributions in previously loaded cracked beams

1992 ◽  
Vol 27 (2) ◽  
pp. 77-83 ◽  
Author(s):  
D J Smith ◽  
M A M Bourke ◽  
A P Hodgson ◽  
G A Webster ◽  
P J Webster
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Crack Tip ◽  
Stress Distributions ◽  
Element Analysis ◽  
Sampling Volume ◽  
Neutron Diffraction Technique ◽  
Good Agreement

The measurement and prediction of residual stress distributions in a fatigue pre-cracked and a plastically overloaded A533B steel beam are described. The residual stresses were obtained experimentally using the neutron diffraction technique. Finite element analysis was employed to predict the elastic-plastic response and residual stresses introduced after overloading. Comparison of the experimental results have been made with the finite element predictions (for both plane stress and strain conditions) averaged over the same sampling volume used to make the neutron diffraction measurements. It has been found that good agreement is achieved away from the near crack tip region. However, close to the crack tip the measured compressive residual stresses are significantly smaller than predicted. This difference is attributed to the A533B steel exhibiting a Bauschinger effect and yielding at a lower stress after a stress reversal.

Neutron diffraction analysis of the residual stress distribution in a bent bar

2000 ◽  
Vol 35 (4) ◽  
pp. 235-246 ◽  
Author(s):  
A. N Ezeilo ◽  
G. A Webster
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Residual Stress Distribution ◽  
Four Point Bending ◽  
Refinement Method ◽  
Nickel Based Alloy ◽  
Neutron Diffraction Technique ◽  
Profile Refinement

A well-characterized residual stress distribution resulting from four-point bending has been analysed using the neutron diffraction technique. Residual stresses were obtained from the strains measured at discrete positions through the bent bar on the (111) and (311) crystal planes of a nickel-based alloy using the appropriate diffraction elastic constants. In addition a profile refinement method was used to determine the residual stresses from average strains from all the diffraction peaks in the spectrum. The measured residual stress profiles have also been compared with strain gauge data and with analytical and finite element predictions. It has been established that the profile refinement approach gives stresses which most closely match those obtained by the non-diffraction techniques.

scholarly journals Residual stress measurements in offshore wind monopile weldments using neutron diffraction technique and contour method

2018 ◽  
Vol 96 ◽  
pp. 418-427 ◽  
Author(s):  
Anais Jacob ◽  
Jeferson Oliveira ◽  
Ali Mehmanparast ◽  
Foroogh Hosseinzadeh ◽  
Joe Kelleher ◽  
...  
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Offshore Wind ◽  
Contour Method ◽  
Stress Measurements ◽  
Neutron Diffraction Technique

The Effectiveness of Cold Rolling for Residual Stress Reduction in Quenched 7050 Aluminium Alloy Forgings

2016 ◽  
Vol 716 ◽  
pp. 521-527 ◽  
Author(s):  
Ran Pan ◽  
Catrin Mair Davies ◽  
Wei Zhang ◽  
Zhusheng Shi ◽  
Thilo Pirling ◽  
...  
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Cold Rolling ◽  
Stress Reduction ◽  
Stress Distributions ◽  
Effective Technique ◽  
The Core ◽  
Cold Rolled ◽  
Neutron Diffraction Technique

Residual stresses are often introduced into aluminum alloys through quenching processes performed to generate the required microstructure. Such residual stresses are known to be deleterious to the integrity of the component. Methods to mitigate residual stresses in quenched components are therefore of great importance. Cold rolling has been proposed as an effective technique to remove residual stresses in large components. In this work, the effectiveness of cold rolling in reducing the residual stresses in quenched blocks AA7050 has been quantified using the neutron diffraction technique. Neutron diffraction measurements have been performed on two blocks one quenched and the other quenched & cold rolled block. Comparing the residual stress distributions pre and post rolling it has been found that cold rolling almost eliminates the tensile residual stresses in the core of the block, however it generates large tensile residual stresses d in a shallow region near the surface of the block.

Residual Stress Analyses by Neutron Diffraction in Irradiated Double-V Butt Welded Steel Plates

2008 ◽  
Vol 571-572 ◽  
pp. 381-386 ◽  
Author(s):  
Dimitar Neov ◽  
Carsten Ohms ◽  
Robert C. Wimpory ◽  
A.G. Youtsos
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Neutron Radiation ◽  
Steel Plates ◽  
Research Centre ◽  
Joint Research ◽  
Stress Measurements ◽  
Water Reactors ◽  
The Impact

Neutron irradiation is known to have a considerable impact on the mechanical characteristics and the behaviour of materials and components. The distribution of residual stresses is one of the properties affected by irradiation. However, because of the difficulties in performing measurements in radioactive components, not many experimental data have to date been collected. At the High Flux Reactor (HFR) of the European Commission’s Joint Research Centre (JRC), a facility has been developed for residual stress measurements in steel specimens subjected to longterm irradiation. The objective of this development was to establish the neutron radiation induced changes in the residual stresses around welds in test pieces representative of the core shroud of boiling water reactors. Residual Stress measurements on such double-V butt welds in stainless steel plates after irradiation exposure have been performed by neutron diffraction using this facility. The comparison with measurements in non-irradiated companion specimens [1] showed that irradiation changed the distribution of residual stresses. The results suggested that the impact of irradiation varied with the distance of the test location from the specimen surface. On the basis of currently measured data we could not draw definitive conclusion about the influence of neutron dose and irradiation duration upon the stress modification.

Residual Stresses Evaluation in Welds and Implications for Design for Pressure Vessel Applications

2006 ◽  
Vol 128 (4) ◽  
pp. 638-643 ◽  
Author(s):  
John W. H. Price ◽  
Anna M. Pardowska ◽  
Raafat Ibrahim ◽  
Trevor R. Finlayson
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Pressure Vessel ◽  
Scale Up ◽  
Small Scale ◽  
Fatigue And Fracture ◽  
Single Bead ◽  
Key Issues ◽  
Neutron Diffraction Technique

Welding residual stresses have important consequences on the performance of engineering components. High residual stresses may lead to loss of performance in corrosion, fatigue, and fracture but as yet these consequences are poorly quantified. The major cause of this is that residual stress often remains the single largest unknown in industrial damage situations since it is difficult to measure or estimate theoretically. One of the key issues in the study of residual stress is that the detail of the stress distribution on a small scale (in the order of millimeters) can be important. In this paper, the neutron diffraction technique is used which while it is a very expensive technique, is capable of nondestructively measuring residual stresses at this scale up to a depth of 35mm. The investigation reported compares the residual stress characteristics due to various restraints for a single bead and in fully restrained samples with different numbers of beads. This paper considers the results of the neutron diffraction studies in relation to fitness for purpose guidance and implication for pressure vessel design.

Residual Stress Modeling of Warm-Bent Tight-Radius CANDU Feeder Bends

2008 ◽  
Author(s):  
Y. Ding ◽  
M. Yetisir
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Thickness Distribution ◽  
Measurement Data ◽  
Future Research ◽  
Cross Sectional ◽  
Simulation Results ◽  
Sectional Shape ◽  
Neutron Diffraction Technique

In one CANDU® nuclear station, a few feeder piping failures have occurred because of stress corrosion cracking. All the cracks were located in tight-radius bends. Root cause analyses indicated that the residual stress played a significant role in these failures. Residual stress measurements using the neutron diffraction technique have been performed to quantify the residual stresses for a large number of feeder bends. Numerical simulations have also been performed to supplement the measurement data. This paper presents the modeling work carried out for 2.5” warm-bent tight-radius feeder bends using LS-DYNA®. The warm-bending process was divided into heating, bending, springback and cooling stages. The simulation results were compared to the measurement data using the neutron diffraction technique. Good agreement was achieved between the trends of simulation results and the measured residual stresses in feeder bends. Additionally, it was found that the predicted cross-sectional shape and wall thickness distribution agreed well with the measurements. Limitations of the simulation work were summarized and recommendations for future research were made based on this study.

scholarly journals Effect of Thermal Residual Stresses on Bonded Structures Containing Cold Expanded and Bolted Holes

2014 ◽  
Vol 996 ◽  
pp. 682-687 ◽  
Author(s):  
Abdul Khadar Syed ◽  
Michael E. Fitzpatrick ◽  
James E. Moffatt
Keyword(s):  
Residual Stress ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Bonding Process ◽  
Expansion Process ◽  
Cold Expansion ◽  
Stress Measurements ◽  
Thermal Residual Stresses ◽  
Compressive Stresses ◽  
Primary Focus

The primary focus of this investigation is to determine the distribution of thermal residual stresses that result during composite bonding processes, and the effect on stresses generated during the subsequent cold expansion of holes. Residual stress measurements were carried out using neutron diffraction techniques. Results show that the cold expansion process resulted in radial compressive stresses 3-4 mm from the edge of the hole and there was no significant effect of thermal residual stresses from the bonding process on the cold expansion and bolted stresses.

scholarly journals Residual Stress Measurements in Mo/CuCrZr Tiles Using Neutron Diffraction

2008 ◽  
Vol 59 ◽  
pp. 299-303
Author(s):  
K. Mergia ◽  
Marco Grattarola ◽  
S. Messoloras ◽  
Carlo Gualco ◽  
Michael Hofmann
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Heat Sink ◽  
High Yield ◽  
Fusion Reactors ◽  
Plasma Facing Components ◽  
Induced Stresses ◽  
Compliant Layer

In plasma facing components (PFC) for nuclear fusion reactors tungsten or carbon based tiles need to be cooled through a heat sink. The joint between the PFC and the heat sink can be realized using a brazing process through the employment of compliant layer of either a low yield material, like copper, or a high yield material, like molybdenum. Experimental verification of the induced stresses during the brazing process is of vital importance. Strains and residual stresses have been measured in Mo/CuCrZr brazed tiles using neutron diffraction. The strains and stresses were measured in Mo tile along the weld direction and at different distances from it. The experimental results are compared with Finite Element Simulations.

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