Public Workshop on Assessment of Residual Stresses in Welds

Wednesday 23 Nov 2022, 09:00 → 18:00 Europe/Berlin

Auditorium Room 0.001 (Institute of Advanced Studies - IAS)

The Technical University of Munich, in collaboration with the European Commission’s Joint Research Centre, is organizing a

 

Workshop on the Assessment of Residual Stresses in Welds

 

on 23 November 2022, 09:00 h to 18:00 h

 

 

to mark the

 

20th Anniversary of the NeT European Network on Neutron Techniques Standardization for Structural Integrity.

                                               

The NeT network is a ~30 partner collaboration, based on voluntary in-kind contributions by the participants, that primarily works on residual stress assessments of welds relevant to nuclear engineering applications.

 

To this end, NeT relies on specimens designed and manufactured within the network. Specimens are typically small-scale mock-ups with a limited number of weld beads, in order to allow for easy exchange between measurement partners and to limit the computational demands for numerical analyses (see 20 Years NeT poster).           

 

The special characteristic of NeT are the extensive residual stress measurement round robin exercises, utilizing a variety of measurement techniques, and the equally extensive numerical simulation round robin exercises. Over the years, NeT has arguably produced some of the best characterized welding residual stress benchmarks in existence.

 

The aim of the Workshop is to provide an insight to the work within NeT, including the development of the specimens, the materials characterization work, residual stress measurement techniques, numerical assessment methods, the lessons learned and how these are utilized in nuclear engineering problems.

 

Attendance of the Workshop is free-of-charge; registration is required. Workshop attendees may be invited – space permitting – to follow also the subsequent regular progress meeting of the NeT European Network on 24 and 25 Nov.

The Workshop is foreseen to be with attendance in-person, provided it is permitted by the pandemic situation at the time. Remote attendance opportunities are in preparation as well. 

20_years_NeT.pdf

09:00 → 09:15 Public NeT Workshop: Welcome

Convener: Juergen Neuhaus

09:15 → 10:30 Public NeT Workshop: Plenary Talks I

Convener: Carsten Ohms

09:15 Into the world - how NeT has influenced Structural Integrity Assessment in UK Nuclear Plant

Speaker: Mike Smith (University Manchester (UK))

NeT in the UK.pdf

10:00 Residual stress: a matter of structural integrity for nuclear reactors

Manufacturing processes results in residual stresses that can be high enough to plastically deform the material. The superposition of residual stresses to those resulting from external loadings can not only contribute to premature failure of structural components, but also affect the driving force for crack initiation and propagation.
In the last year, crack problems have been reported in the nuclear industry, resulting from the association of residual stresses with corrosive environments, high temperatures, internal pressure, and so on. Understanding the physical mechanisms related to the presence of these cracks and developing robust models for its prediction are major challenges of the research carried out at the Energy Division (DES) of CEA.
In this context, the welded joints of structural materials are of high interest as they present mechanical and microstructural discontinuities within the structural material due the successive torch passes during the welding process. Instrumented experimental tests and numerical simulation studies have therefore been carried out in order to master welding processes, in order to better understand their effects on different materials.
In relation with the NeT activites, these studies allows:
• validating numerical welding models (finite element code Cast3M) in respect to experimental measurements and observations (residual stress, plastic strain, temperature, microstructure and so on);
• improving the existing material property databases and discussing on suitable constitutive material behavior for welding simulations;
• obtaining a better knowledge on residual stress profiles and on their effect on crack triggering.

Speaker: Diogo Goncalvez (CEA)

NeT_meeting_Nov2022_DGONCALVES_no-animation.pdf

10:30 → 11:00 Coffee break

11:00 → 12:30 Public NeT Workshop: Plenary Talks II

Convener: Mike Smith

11:00 How you can implement the lessons learned from NeT round robins to day-to-day problems in nuclear industry

Speaker: Vincent Robin (EDF (F))

20221122 - NeT Workshop - EDF - Disseminated version.pdf

11:45 Application of the contour method to NeT components

Speaker: John Bouchard (Open University (UK))

NeT_Contour 2022.pdf

12:05 Lessons learnt from NeT and applied to other projects like NNUMAN/ATLAS+ or MATTEAR

Speaker: Anastasia Vasileiou (University Manchester (UK))

12:30 → 14:00 Lunch Break

14:00 → 15:20 Public NeT Workshop: Methods

Convener: Anastasius Youtsos

14:00 Deep hole drilling (DHD) measurements and observations of the first 20 years of NeT TG specimens

Speaker: Chris Truman (University Bristol (UK))

UB-DHD-NeT.pdf

14:20 Neutron Diffraction in NeT

Diffraction methods are powerful tools for non-destructive analysis of applied or residual stresses. The high penetrating power of neutrons when compared to laboratory x-ray sources, i.e. several cm instead of a few tens of μm, opens up the possibility to analyze residual stresses in the interior of technical components rather than just at the surface. This makes neutrons an ideal tool for residual stress determination in thick samples like the welded test specimens used in the different NeT task groups.
In addition, the possibility to keep the measurement gauge volume cubic in all possible sample orientations is extremely helpful in order to analyze the local stress tensor used to validate the extensive numerical simulations of the corresponding NeT task group projects.
In this presentation, we will give an overview on the basic principles and requirements of the method and its use within NeT. A few key examples are given as well as a quick review on lessons learned during the measurement campaigns.

Speaker: Michael Hofmann

Hofmann_Neutron_Diffraction_in_NeT.pdf

14:40 Uncertainties due to grain size issues in residual stress determinations using neutron diffraction

Speaker: Robert Wimpory (Helmholtz Zentrum Berlin (D))

Wimpory_Net 2022 Munich.pdf

15:00 A deconvolution method for the mapping of residual stresses by diffraction

Speaker: Chedley Braham (Arts et Métiers ParisTech)

NET meeting_Deconvolution C Braham.pdf

15:20 → 15:50 Coffee break

15:50 → 17:30 Public NeT Workshop: Numerical Modelling

Convener: Vincent Robin

15:50 Numerical activities for the NeT Task Groups

Speaker: Lionel Depradeux (EC2 Modélisation (F))

Lionel_NET_41th_EC2_Workshop_2022.pdf

16:10 NeT–TG6: Three superimposed Alloy 82 weld beads on a plate Alloy 600 nickel-base superalloy using TIG

Speaker: Vasileios Akrivos (University Manchester (UK))

NeT Workshop Nov 22 Akrivos 23112022.pdf

16:30 Wire + arc additive manufacturing : the challenge of distortions and residual stresses

Speaker: Issam Bendaoud (Universite Montepellier (F))

2022_11_23_TG9_NETmeeting.pdf

16:50 20 years of NeT, a summary of the achievements

Speaker: Carsten Ohms (JRC Petten (NL))

NeT_20th_Anniversary Workshop_JRC_Summary.pdf

17:10 Final Discussion, Round up