Abstract
An incremental Contour Method (iCM) of residual stress measurement is proposed where residual stresses in the body of interest are sequentially reduced by successive contour cuts and the risk of stress re-distribution plasticity is mitigated or eliminated. The cutting-induced plasticity is known to cause significant inaccuracies when trying to measure the near-yield residual stresses using a conventional single cut contour method. The iCM procedure implements a new displacement data processing approach for the general case of sectioning at an arbitrary plane where the cut parts do not possess mirror-symmetric elastic stiffness. The basis for the new asymmetric stiffness data analysis approach is presented and the accuracy of the new method demonstrated using both numerical and experimental case studies.
Highlights
Residual stresses introduced by manufacturing processes can combine with operational stresses and result in unexpected overload or premature failure of components
The standard contour method involves: (i) sectioning a body into two mirror-symmetric halves along a plane of interest using wire electro-discharge machining (EDM), (ii) measuring the out-ofplane displacement of the created cut surfaces associated with the release of residual stress, (iii) processing the measured displacements to remove the effect of shear stress, any artefacts introduced by the wire EDM cutting process, and to smooth the scatter in the data, and (iv) applying the displacement “contour” as a surface boundary condition to a Finite Element (FE) model of one of the cut parts and conducting an elastic stress analysis to back-calculate the original residual stress acting normal to the cut plane [3,4]
We address the generic problem of dealing with contour cut parts having asymmetric stiffness
Summary
Residual stresses introduced by manufacturing processes can combine with operational stresses and result in unexpected overload or premature failure of components. Recent work [10] has experimentally demonstrated how different cutting path configurations can be employed to minimise the amount of cutting induced plasticity and its effect on the accuracy of stresses determined by the contour method This approach is a costly and time-consuming process. The idea is to repeatedly reduce the size of component, and magnitude of residual stress remaining in it, using successive contour cuts such that near zero plasticity occurs during any of the cuts This proposed ‘incremental Contour Method’ (iCM) relies on the principle of superposition where out-of-plane displacements obtained by the standard contour method from the first cut are applied as a boundary condition to that cut face when determining residual stresses at the second cut face and so forth for subsequent cuts. We demonstrate the efficacy of the proposed iCM approach in mitigating plasticity induced errors, compared with the standard contour method, via numerical simulation of an international residual stress round-robin benchmark specimen
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
