Validation Specimen for Contour Method Extension to Multiple Residual Stress Components


A new theoretical development has been made that will allow the contour method to measure a cross-sectional map of not just the normal stress but all three normal stress components. To validate this development, a residual stress test specimen was designed, fabricated and then tested with different experimental techniques. A 60-mm diameter ×10-mm thick disk of 316L stainless steel was plastically compressed through the thickness with a 15 mm diameter flat indenter in the center of the disk to provide a unique biaxial stress state that is ideal for testing the theory. The stresses in the specimen were first mapped using time-of-flight neutron diffraction. Next, the hoop stresses were mapped on a cross-section using the contour method, and the agreement with the neutron measurements was excellent. The extension of the contour method to multiple components requires the measurement of in-plane stresses on the cut surface, after electrochemical removal of material affected by the cut. An initial attempt to measure the in-plane stresses using x-ray diffraction was unsuccessful because of the large grain size of the material. Further attempts will be made using hole drilling. A finite element prediction of the stresses from the indentation process gave reasonable agreements with the data but was limited in its accuracy because the 316L showed a Bauschinger effects that has not yet been correctly modelled. The indented specimen makes an excellent residual stress test specimen, and suggestions for improving the specimen are given.

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@inproceedings{Pagliaro2007ValidationSF, title={Validation Specimen for Contour Method Extension to Multiple Residual Stress Components}, author={Pierluigi Pagliaro and M. B. Prime and Biagio Zuccarello and Bj\orn Clausen}, year={2007} }