Long term stress relaxation modelling

Stefan Holmström, Pertti Auerkari, V. Friedmann, A. Klenk, B. Leibing, P. Buhl, M. Spindler, A. Riva

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

Abstract

Data assessments, materials modelling and development as well as recommendations for model selection have been a main objective of the ECCC Working Group 1. This paper describes the latest inter-comparison round robin on relaxation modelling. Most models found in the public domain are limited in either strain range or temperature. Here the bolting steel 1Cr-0.5Mo-0.25V steel tested by NIMS, Japan is assessed by a number of assessors striving to define models capable of predicting the relaxation in the full data range, i.e. in both strain (0.1-0.25% total strain) and temperature (450-550°C). The assessors use methods of their own preference giving all model parameters to enable interpolation/extrapolation and calculation of prediction errors within the range of data. The methods include forward creep with different creep strain models as base, classical relaxation models, parametric (Time-Temperature-Parameter curve families) solutions and entirely new modelling approaches. The main target is the general overall model for prediction of relaxed stress up to 3 000 h hold time. However, the model robustness is tested by fitting to a drastically culled data set consisting of only the short term data with durations of 0.1 to 10h. The predictive performance of the models optimised for the short term data are compared with the long term data as well as the long term models. Conclusions and recommendations are given on model interpolation performance, extrapolation ability and model complexity.
Original languageEnglish
Title of host publicationECCC 2014 Conference Proceedings
Number of pages15
Publication statusPublished - 2014
MoE publication typeA4 Article in a conference publication
Event3rd International ECCC Conference, ECCC 2014: ECCC 2014 Creep & Fracture in High Temperature Components, Design & Life Assessment - Rome, Italy
Duration: 5 May 20147 May 2014
Conference number: 3

Conference

Conference3rd International ECCC Conference, ECCC 2014
Abbreviated titleECCC 2014
CountryItaly
CityRome
Period5/05/147/05/14

Fingerprint

modeling
creep
interpolation
steel
temperature
prediction
recommendation
method
parameter

Keywords

  • stress relaxation
  • modelling

Cite this

Holmström, S., Auerkari, P., Friedmann, V., Klenk, A., Leibing, B., Buhl, P., ... Riva, A. (2014). Long term stress relaxation modelling. In ECCC 2014 Conference Proceedings
Holmström, Stefan ; Auerkari, Pertti ; Friedmann, V. ; Klenk, A. ; Leibing, B. ; Buhl, P. ; Spindler, M. ; Riva, A. / Long term stress relaxation modelling. ECCC 2014 Conference Proceedings. 2014.
@inproceedings{fd02b3ec748645f8bb9186066759fd2d,
title = "Long term stress relaxation modelling",
abstract = "Data assessments, materials modelling and development as well as recommendations for model selection have been a main objective of the ECCC Working Group 1. This paper describes the latest inter-comparison round robin on relaxation modelling. Most models found in the public domain are limited in either strain range or temperature. Here the bolting steel 1Cr-0.5Mo-0.25V steel tested by NIMS, Japan is assessed by a number of assessors striving to define models capable of predicting the relaxation in the full data range, i.e. in both strain (0.1-0.25{\%} total strain) and temperature (450-550°C). The assessors use methods of their own preference giving all model parameters to enable interpolation/extrapolation and calculation of prediction errors within the range of data. The methods include forward creep with different creep strain models as base, classical relaxation models, parametric (Time-Temperature-Parameter curve families) solutions and entirely new modelling approaches. The main target is the general overall model for prediction of relaxed stress up to 3 000 h hold time. However, the model robustness is tested by fitting to a drastically culled data set consisting of only the short term data with durations of 0.1 to 10h. The predictive performance of the models optimised for the short term data are compared with the long term data as well as the long term models. Conclusions and recommendations are given on model interpolation performance, extrapolation ability and model complexity.",
keywords = "stress relaxation, modelling",
author = "Stefan Holmstr{\"o}m and Pertti Auerkari and V. Friedmann and A. Klenk and B. Leibing and P. Buhl and M. Spindler and A. Riva",
year = "2014",
language = "English",
booktitle = "ECCC 2014 Conference Proceedings",

}

Holmström, S, Auerkari, P, Friedmann, V, Klenk, A, Leibing, B, Buhl, P, Spindler, M & Riva, A 2014, Long term stress relaxation modelling. in ECCC 2014 Conference Proceedings. 3rd International ECCC Conference, ECCC 2014, Rome, Italy, 5/05/14.

Long term stress relaxation modelling. / Holmström, Stefan; Auerkari, Pertti; Friedmann, V.; Klenk, A.; Leibing, B.; Buhl, P.; Spindler, M.; Riva, A.

ECCC 2014 Conference Proceedings. 2014.

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

TY - GEN

T1 - Long term stress relaxation modelling

AU - Holmström, Stefan

AU - Auerkari, Pertti

AU - Friedmann, V.

AU - Klenk, A.

AU - Leibing, B.

AU - Buhl, P.

AU - Spindler, M.

AU - Riva, A.

PY - 2014

Y1 - 2014

N2 - Data assessments, materials modelling and development as well as recommendations for model selection have been a main objective of the ECCC Working Group 1. This paper describes the latest inter-comparison round robin on relaxation modelling. Most models found in the public domain are limited in either strain range or temperature. Here the bolting steel 1Cr-0.5Mo-0.25V steel tested by NIMS, Japan is assessed by a number of assessors striving to define models capable of predicting the relaxation in the full data range, i.e. in both strain (0.1-0.25% total strain) and temperature (450-550°C). The assessors use methods of their own preference giving all model parameters to enable interpolation/extrapolation and calculation of prediction errors within the range of data. The methods include forward creep with different creep strain models as base, classical relaxation models, parametric (Time-Temperature-Parameter curve families) solutions and entirely new modelling approaches. The main target is the general overall model for prediction of relaxed stress up to 3 000 h hold time. However, the model robustness is tested by fitting to a drastically culled data set consisting of only the short term data with durations of 0.1 to 10h. The predictive performance of the models optimised for the short term data are compared with the long term data as well as the long term models. Conclusions and recommendations are given on model interpolation performance, extrapolation ability and model complexity.

AB - Data assessments, materials modelling and development as well as recommendations for model selection have been a main objective of the ECCC Working Group 1. This paper describes the latest inter-comparison round robin on relaxation modelling. Most models found in the public domain are limited in either strain range or temperature. Here the bolting steel 1Cr-0.5Mo-0.25V steel tested by NIMS, Japan is assessed by a number of assessors striving to define models capable of predicting the relaxation in the full data range, i.e. in both strain (0.1-0.25% total strain) and temperature (450-550°C). The assessors use methods of their own preference giving all model parameters to enable interpolation/extrapolation and calculation of prediction errors within the range of data. The methods include forward creep with different creep strain models as base, classical relaxation models, parametric (Time-Temperature-Parameter curve families) solutions and entirely new modelling approaches. The main target is the general overall model for prediction of relaxed stress up to 3 000 h hold time. However, the model robustness is tested by fitting to a drastically culled data set consisting of only the short term data with durations of 0.1 to 10h. The predictive performance of the models optimised for the short term data are compared with the long term data as well as the long term models. Conclusions and recommendations are given on model interpolation performance, extrapolation ability and model complexity.

KW - stress relaxation

KW - modelling

M3 - Conference article in proceedings

BT - ECCC 2014 Conference Proceedings

ER -

Holmström S, Auerkari P, Friedmann V, Klenk A, Leibing B, Buhl P et al. Long term stress relaxation modelling. In ECCC 2014 Conference Proceedings. 2014