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Residual Stress
Conferences |
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Summary
- Overall, the contour method results agree well with the majority of the independent validations.
- For non-weld specimens, agreement is almost always very good.
- Most uncertainties in papers are for 1 standard deviation (sd). Statistically, independent measurements should agree to within one sd error bars at something like only 68% of the points. The remainder should disagree randomly.
- There are some results where contour seems to have a systematic error, some when the other method has an error, and some are not possible to tell.
- Contour systematic errors are discussed below the table.
- The more textured the material, or the higher the intergranular stress (micro stress or type II), or when there are chemistry changes, the less likely for contour and diffraction to agree. This hints at a diffraction issue. Welds usually fall in this category.
- The results on the NeT specimen and the VPPA weld show the scatter in multiple neutron or synchrotron results - important to keep in mind when comparing with a single measurement.
- There are some contour errors in this table that are caused by sub-optimal data processing and could be improved.
The table below attempts to show all significant experimental validations (verifications) of the contour method. Comparisons at different points (e.g., surface vs. bulk) or only a few points are not included. If there are additional validations that should be included or any of these details or characterizations are misleading, please email Mike Prime.
Article (reverse chronological) |
Specimen and Materials |
Comparison |
Results and comments |
 Zabeen, S., Preuss, M., and Withers, P., 2013, "Residual stresses caused by head-on and 45° foreign object damage for a laser shock peened Ti-6Al-4V alloy aerofoil," Materials Science and Engineering: A, 10, pp. 518–527. U. Manchester. |
Airfoil shapes of Ti-6Al-4V |
Synchrotron diffraction |
Good agreement at one measurement location (as laser-peened) and very good at the other (near foreign object damage). |
| Kundu, A., Bouchard, P., Kumar, S., Venkata, K., Francis, J., Paradowska, A., Dey, G., and Truman, C., 2013, "Residual stresses in P91 steel electron beam welds," Science and Technology of Welding & Joining, 18(1), pp. 70-75. The Open University. |
E-beam welded plates of PP91 ferritic-martensitic steels. |
Neutron diffraction |
Only fair agreement. Differences of about 100 MPa. Contour may have not resolved the peaks, but also lots of variation and scatter in neutron d0 measurements. |
| Traore, Y., Paddea, S., Bouchard, P., and Gharghouri, M., 2012, "Measurement of the Residual Stress Tensor in a Compact Tension Weld Specimen," Experimental Mechanics. The Open University. |
E-beam welded compact tension specimen of austenitic stainless steel. |
Neutron diffraction and slitting. |
Very good agreement. A slight shift in the contour results could be a bulge error since the part was only clamped on one side during the cut. |
| Hosseinzadeh, F., Toparli, M. B., Bouchard, P. J., 2012, "Slitting and Contour Method Residual Stress Measurements in an Edge Welded Beam," J. of Pressure Vessel Technology, 134(1), pp. 011402-011406. The Open University. |
Edge welded beam of 316H stainless steel. Specimen only clamped on one side during EDM cut - likely to increase errors. |
Neutron diffraction, synchrotron diffraction, and slitting. |
Very good agreement with synchrotron (noisy) and slitting. Fair to good agreement with neutron. |
| Savaria, V., Hoseini, M., Bridier, F., Bocher, P., and Arkinson, P., 2011, "On the measurement of residual stress in induction hardened parts," Materials Science Forum, 681, pp. 431-436. |
Case hardened disks of 4340 steel. |
X-ray diffraction with layer removal. |
Compared only for about 2 mm of depth and mostly poor agreement. They used a zinc coated EDM wire, which some have found to be a problem. |
| Moat, R. J., Pinkerton, A. J., Li, L., Withers, P. J., and Preuss, M., 2011, "Residual stresses in laser direct metal deposited Waspaloy," Materials Science and Engineering, A528(6), pp. 2288-2298. U. Manchester, School of Materials. |
Laser-deposited Waspaloy (nickel-based superalloy) |
Neutron diffraction - single peak {3 1 1}. d0 determined by assuming 0 stress in thin direction. |
Very good agreement (within error bars). Such is often the case in specimens other than welds. |
 Brown DW, Holden TM, Clausen B, Prime MB, Sisneros TA, Swenson H, Vaja J, 2011, "Critical Comparison of Two Independent Measurements of Residual Stress in an Electron-Beam Welded Uranium Cylinder: Neutron Diffraction and the Contour Method," Acta Materialia 59 (3):864-873. doi:10.1016/j.actamat.2010.09.022. |
Circumferentially (girth) welded cylinder of depleted uranium (Orthorhombic crystal structure) |
Neutron diffraction - time of flight and Rietveld refinement. |
Fair to poor agreement quantitatively although good qualitatively. However, the neutron measurements were averaged over the circumference, so not directly comparable. Also, see the discussion in the paper: these measurements were very challenging for both methods, so several possible error sources. |
| Pagliaro, P., Prime, M. B., Robinson, J. S., Clausen, B., Swenson, H., Steinzig, M., and Zuccarello, B., 2010, "Measuring Inaccessible Residual Stresses Using Multiple Methods and Superposition," Experimental Mechanics, doi:10.1007/s11340-010-9424-5. (LA-UR-10-02450) |
Plastically indented disks of 2024-T351 aluminum alloy. |
Neutron diffraction - time of flight and Rietveld refinement. |
Good agreement (within error bars) over most of the profile for traditional contour measurement, see Figure 9. Also quite good agreement for Surface Superposition Contour Method to get multiple stress components, see Figure 12 |
| Thibault D, Bocher P, Thomas M, Gharghouri M, Côté M, "Residual stress characterization in low transformation temperature 13%Cr-4%Ni stainless steel weld by neutron diffraction and the contour method," Materials Science and Engineering: A, 527(23):6205-6210, 2010. Institut de recherche d'Hydro-Québec (IREQ), Québec, Canada. |
Plate of martensitic steel welded with 410NiMo filler, also martensitic. |
Neutron diffraction. |
Good agreement over much of the measurements. Poor agreement in the Heat-Affected Zone. Authors' explanation is that the HAZ has retained austenite but stresses were only measured in the martensitic phase. Contour measures total stress, which is an average. |
| Pagliaro, P., Prime, M. B., Swenson, H., and Zuccarello, B., "Measuring Multiple Residual-Stress Components Using the Contour Method and Multiple Cuts," Experimental Mechanics, 50(2), pp. 187-194, 2010. (LA-UR-09-01120) |
Plastically indented disks of 316L stainless steel. Same specimen as next paper below. |
Neutron diffraction - time of flight and Rietveld refinement. |
One additional results to paper below. Very good agreement (within error bars) to validate multiple cuts procedure. |
| Pagliaro, P., Prime, M. B., Clausen, B., Lovato, M. L., and Zuccarello, B., "Known Residual Stress Specimens Using Opposed Indentation," J. of Engineering Materials and Technology, 131, 031002, 2009. |
Plastically indented disks of 316L stainless steel. |
Neutron diffraction - time of flight and Rietveld refinement. |
Very good agreement (within error bars) over most of the profile. See Figure 15. Some disagreement from r = 10 to 20 mm. |
| Frankel, P.; Preuss, M.; Steuwer, A.; Withers, P.J.; Bray, S., "Comparison of residual stresses in Ti-6Al-4V and Ti-6Al-2Sn-4Zr-2Mo linear friction welds," Materials Science and Technology, 25(5), 640-650, 2009. Multiple institutions. |
Linear friction welded Ti-6Al-4V, one as welded and two different heat treatments. |
Synchrotron diffraction with d0 measurements by laboratory x-ray. |
Contour peak stresses are significantly lower then synchrotron results. Could be contour issues. Weld region has severe microstructural gradients and is a two-phase alloy, making diffraction challenging. See Johnson thesis for earlier reporting of similar (same?) measurements showing better agreement. |
NeT 2009 special issue of I.J. of Pressure Vessels and Piping. Multiple institutions.
also in Bouchard, PJ, 2008, "Code Characterisation of Weld Residual Stress Levels and the Problem of Innate Scatter," Int. J. of Pressure Vessels and Piping 85:152-165. |
Bead-on-plate TIG weld on 316L stainless steel plate. |
4 Neutron diffraction measurements at different labs. Also 1 deep hole drilling measurement. |
Good to very good agreement. One profile shows contour results right in the middle of scatter of neutron and deep hole results. Another profile shows contour results on low side of scatter. This comparison is especially informative because of scatter in multiple measurements. |
| DeWald, AT ; Hill, MR, Eigenstrain-based model for prediction of laser peening residual stresses in arbitrary three-dimensional bodies. Part 1: model description , Journal of Strain Analysis for Engineering Design, 44(1), 1-11, 2009. U. C. Davis. |
Laser peened blocks, 4 thicknesses 10-40 mm. 316L stainless steel. |
Slitting (crack compliance). |
In general quite good agreement. Not as good within 2 mm of the surface (surface stresses are difficult with contour.) |
(26 MB) Johnson, G, 2008, "Residual stress measurements using the
contour method," Ph.D. Dissertation, University of Manchester, School of Materials.
(results not published elsewhere listed here) |
Chapter 6: Hoop stress in inertia friction welded cylinders of Aermet 100 (ultra high strength steel) to SCMV (Super Chromium Molybdenum pressure Vessel Steel)
Chapter 7:
Linear friction welded Ti-6Al-4V, one as welded and two different heat treatments. |
Neutron diffraction.
Synchrotron diffraction. |
After correcting for cutting artifacts, good agreement. See this publication on the issue of measuring hoop stresses in cylinders - a two cut process works better.
Very good agreement. Johnson developed a nice process for processing data with very high local gradients and smooth variations elsewhere. Best validation for such a situation. |
| Dennis, R. J., Bray, D.P., Leggatt, N.A., Turski, M. , 2008, "Assessment of the Influence of Plasticity and Constraint on Measured Residual Stresses Using the Contour Method." 2008 ASME Pressure Vessels and Piping Division Conference, Chicago, IL, USA, PVP2008-61490. Frazer-Nash Consultancy and U. Manchester. |
3 pass groove weld. 316L Austenitic stainless steel. Results from Kartal et al. study. |
Neutron diffraction. |
Results on a region with poor agreement were simulated with FEM to explain errors as a result of plasticity. May actually also have a bulge effect. |
| M.E. Kartal, C.D.M. Liljedahl, S. Gungor, L. Edwards, M.E. Fitzpatrick, "Determination of the profile of the complete residual stress tensor in a VPPA weld using the multi-axial contour method," Acta Materialia, 56(16), 4417-4428, 2008. The Open University |
Variable-Polarity Plasma-Arc (VPPA) autogenous butt weld. 2024-T351 Aluminum plate |
Neutron diffraction. |
Mostly very good agreement for longitudinal stresses. 17 MPa rms disagreement! Some disagreement at one edge (bulge error?). Also good agreement for transverse stresses to verify DeWald/Hill multiaxial method, but those stresses are quite small. |
| Richter-Trummer, V., Tavares, S. M. O., Moreira, P. M. G. P. et al. "Residual stress measurement using the contour and the sectioning methods in a MIG weld: Effects on the stress intensity factor." Ciência & Tecnologia dos Materiais, 20(1-2), p.114-119, 2008. U. Porto |
Single MIG weld bead on a thin plate of 6082-T6 Aluminum. |
Sectioning. |
Very good agreement, 1-D stress profile only. |
| Withers, P.J.; Turski, M.; Edwards, L.; Bouchard, P.J.; Buttle, D.J., "Recent advances in residual stress measurement," Int. J. of Pressure Vessels and Piping, 85, 118-127, 2008. U. of Manchester et al. |
Single bead on plate weld. 316H Stainless steel. |
Neutron diffraction. |
Agreement was very good over half of the profile but differences as much as 100 MPa elsewhere. Could be a bulge error in contour results. |
| W. Woo, H. Choo, M. B. Prime, Z. Feng, and B. Clausen, “Microstructure, texture and residual stress in a friction-stir-processed AZ31B magnesium alloy,” Acta Materialia, 56(8), 1701-1711, 2008. |
Friction stir weld (or friction stir processed) Magnesium AZ31B |
Neutron diffraction. |
Agreement was good, generally within uncertainty but not always. There were ambiguities in interpreting the
neutron diffraction results due to texture. |
| A. Evans; G. Johnson; A. King; P. J. Withers, "Characterization of laser peening residual stresses in Al 7075 by synchrotron diffraction and the contour method," J. of Neutron Research, 15(2), 147 - 154, 2007. U. of Manchester. Also with more details in Johnson thesis (pdf). |
2 Laser peened plates- 1 single location and 1 overlapping. 7075-T351 Aluminum. |
Synchrotron diffraction using a plane stress assumption. |
Agreement was good. Synchrotron stresses tended to be 50 MPa more compressive (could be d0), and shifted a little (could be bulge). Agreement was good all the way to surface because of careful work on contour. |
| H. Nasri, J. Lanteigne, and H. Champliaud, "Usage of the Contour Method in Measuring Residual Stress in Welding and Peen-Welding Applications," Proc. of the IASTED Asian Conference: Modelling and Simulation, Beijing, China, 2007, ISBN CD 978-0-88986-701-7, Paper 571-801. École de technologie supérieure (U. Québec) and Institut de recherche d’Hydro-Québec. |
A516 carbon steel plates welded in a V-groove and then one plate hammer peened. |
Hole drilling. About 5 points taken across the weld bead on the surface. Hole depth is not stated. |
Agreement is good. Contour does not measure surface stresses well, so one should not expect too much. Stresses were very high, so plasticity errors possible for hole drilling and contour. |
| Prime, M. B., Gnäupel-Herold, T., Baumann, J. A., Lederich, R. J., Bowden, D. M., Sebring, R.J., "Residual Stress Measurements in a Thick, Dissimilar Aluminum Alloy Friction Stir Weld,” Acta Materialia, 54(15), 4013-4021, 2006. |
Friction stir weld butt joint in 25 mm thick plates of 2024-T351 and 7070-T7451 Aluminum. |
Neutron diffraction. |
Agreement is excellent in weld region especially considering the low stresses (< 40 MPa). 20 MPa difference in base material, which may have intergranular stresses. |
| Kartal, M ; Turski, M ; Johnson, G ; Fitzpatrick, ME ; Gungor, S ; Withers, PJ ; Edwards, L, "Residual stress measurements in single and multi-pass groove weld specimens using neutron diffraction and the contour method," Materials Science Forum, Vols. 524-525, pp. 671-676, 2006. The Open University and U. of Manchester. |
1 and 3 pass groove weld. 316L Austenitic stainless steel. |
Neutron diffraction. |
Good general agreement, but not everywhere. Some of the disagreement is attributed to how the contour data was processed. See Dennis et al. for more results from this study with larger disagreement. |
| Y. Zhang, S. Pratihar , M. E. Fitzpatrick and L. Edwards, ‘Residual stress mapping in welds using the contour method', Mater. Sci. Forum , 490, 294-299, 2005. The Open University. |
Bead-on-plate metal arc weld. 316L Austenitic stainless steel. |
Neutron diffraction at only 7 points. |
Trends are same, neutron results are higher by 50 MPa. Reference lattice parameter (d0) errors for neutron could be part of that. The authors also report some cutting difficulties which may have affected contour. |
| Zhang,
Y.; Ganguly, S.; Edwards, L.; Fitzpatrick, M.E., "Cross-sectional
mapping of residual stresses in a VPPA weld using the contour method," Acta Materialia, 52(17), pp. 5225-5232, October 2004. The Open University. |
Variable-polarity plasma-arc (VPPA) weld. 2024-T351 Aluminum. |
Synchrotron and neutron. Independent of each other. |
Agreement is good. Contour is mostly right in the middle of the scatter between neutron and synchrotron. All 3 methods agree/disagree about equally. |
| M. B. Prime, R. J. Sebring, J. M. Edwards, D. J. Hughes, P. J. Webster,
"Laser Surface-Contouring and Spline Data-Smoothing for Residual
Stress Measurement," Experimental Mechanics, 44(2),
pp. 176-184, April 2004. |
TIG weld using filler metal. BS 4360 Grade 50D ferritic steel. |
Neutron diffraction (reactor using 211 reflection) |
Agrees quite well but not perfectly. Neutron and contour were done on different sections of long specimen. Unfortunately, neutron round robin results were only published for one strain component. It would be nice to see how much scatter there was. |
| Zhang, Y., Ganguly, S., Stelmukh, V., Fitzpatrick, M. E., and Edwards, L., "Validation of the Contour Method of Residual Stress Measurement in a MIG 2024 Weld by Neutron and Synchrotron X-Ray Diffraction," J. of Neutron Research, 11(4), pp. 181-185, 2003. The Open University. |
MIG Butt weld (double V). 2024-T351 Aluminum |
Synchrotron (measure 2 strains, assume uniaxial stress). Also some neutron results. |
Agreement is quite good. Trends and magnitudes are same, but synchrotron results have bigger amplitude variations. Contour data was possibly over-smoothed. |
| M.
B. Prime, "Cross-Sectional Mapping of Residual Stresses by Measuring
the Surface Contour After a Cut," Journal of Engineering Materials
and Technology, 123, pp. 162-168, 2001. |
Plastically bent beam. 21Cr-6Ni-9Mn austenitic stainless steel. (Nitronic 40). |
Experimentally determined during bending from strains and loads. |
Agrees well. Contour peak stresses are slightly lower magnitude, but within uncertainty of "known" stresses. |
There are some trends in the differences that are caused by contour systematic errors or other issues:
- As stresses are released, stretching or compressing of the material right in from of the cut causes an error that can shift contour results a little (like a phase shift) and reduce stress magnitudes. Good restraint can usually keep this error below 5-10 %. Sometimes called a "bulge" error. Tends to accumulate some as cut gets deeper - so error depends on cut direction. Look for a future publication on this. See
M. B. Prime and A. L. Kastengren, "The Contour Method Cutting Assumption: Error Minimization
and Correction" Proceedings of the SEM Annual Conference & Exposition on
Experimental and Applied Mechanics
Indianapolis, Indiana USA, Society for Experimental
Mechanics Inc., June 7 - 9, 2010, paper # 507 (LA-UR-10-1605).
- Plasticity at the cut tip can cause errors. Depends on stress magnitude and cyclic yield strength. Good restraint reduces this error. Hard to distinguish from the error in previous bullet.
- Contour does not generally measure surface stresses well because of difficulty getting a perfect cut and good data right up to the edge of the surface. One must also use special care processing the data. Most careful study done by Alex Evans and Greg Johnson shows that you can get good results as close as 100 µm from surface with careful experiment and analysis.
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