12 research outputs found
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Development of a residual stress simulation benchmark for a single bead-on-plate benchmark
Finite element weld residual stress modelling procedures involve complex non-linear analyses where many assumptions and approximations have to be made by the analyst. Weld modelling guidelines for inclusion in the R6 defect assessment procedure are in preparation and will be accompanied by a series of validation benchmarks that can be used to evaluate the accuracy of weld modelling procedures and assess their suitability for use in fracture assessments. It is intended to base one of the benchmarks on a stainless steel bead-on-plate weldment that has been extensively studied by members of Task Group 1 of the NeT European Network project. This paper uses round robin residual stress measurements from the NeT project to derive a statistically based ‘best estimate’ distribution of transverse stress passing through the wall-section at mid-length of the bead-on-plate weldment. The accuracy of a state-of-the-art residual stress prediction is benchmarked against the best estimate measurements using a root mean square error analysis and comparisons of decomposed components of stress. The appropriateness of using the predicted residual stresses in fracture assessments is assessed by comparing stress intensity factors based on the measured and predicted distributions of stress. The results from these studies will be used to help establish accuracy targets and acceptance criteria for the welding benchmark
Measurement of residual stress in materials using neutrons. Proceedings of a technical meeting held in Vienna 13 17 October, 2003
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Management of nuclear power plant operation by optimising weld repairs - ENPOWER project overview
ENPOWER is a EURATOM collaborative research project sponsored by the European Union. The aim is to produce advanced weld repair techniques and residual stress mitigation procedures for nuclear components in order to eliminate the need for expensive global Post-Weld Heat Treatment (PWHT). These procedures are based on weld repair optimisation combined with novel Alternative Post Weld Treatments (APWT)
The European network on Neutron Techniques Standardization for Structural Integrity - NeT
This paper provides an overview over the work of the European Network on Neutron Techniques Standardization for Structural Integrity NeT . The network involves some 35 organisations from industry and academia and these partners undertake the application of modern experimental and numerical techniques to problems related to the structural integrity of components, mainly relevant to nuclear applications. While being built around neutron scattering techniques, which are predominantly applied for analyses of welding residual stresses, one of the major strengths of the consortium is the diversity in available experimental and numerical techniques. In the residual stress area, for example, many types of materials characterizations testing, several methods for residual stress analysis, including neutron and Xray diffraction, deep hole drilling, the contour method and others, and many different ways of numerical analysis employing several commercially available FEM codes can be covered by the partners. Currently the network has embarked on five different Task Groups. Four of these are dealing with welding residual stress assessment, and one applies Small Angle Neutron Scattering for studying thermal ageing processes in duplex stainless steels used for reactor core internals. The work already performed in the context of NeT and the envisaged investigations for the ongoing Task Groups are briefly outlined in this paper. The aim is to give the reader a comprehensive overview of the work of NeT and to shed some light on the potential present in this kind of collaborative effor