Predicting creep strain response from rupture data and a robust creep curve model

Stefan Holmström, Pertti Auerkari, Stuart Holdsworth

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

1 Citation (Scopus)

Abstract

Creep strain evolution plays a critical role in design and in life assessment of components subjected to service at high temperatures. For instance in turbines, boilers and steam pipes the recommended limits are 1% or 2% of strain. Unfortunately, straightforward engineering methodologies for predicting long term creep strain are not readily available. Robust methods for creep rupture extrapolation have been developed for example in the recommended procedures of the European Creep Collaborative Committee (ECCC) and PD6605 of BSI. The recently developed logistic creep strain prediction (LCSP) model transfers robustness into creep strain modelling. The LCSP model is directly linked to the rupture model and applies a small set of creep curve shape parameters to adjust primary, secondary and tertiary creep properties. The stress and temperature dependence of these shape parameters is optimised by fitting the available strain data. In this work the LCSP model was acquired for P22 steel from a small data set (max 3000 h) together with standard data for time to 1% strain. The model was then used to predict time to strain (0.5 to 5%) for two other P22 data sets using only true time to rupture. The model was also inversely applied to predict time to rupture from values of time to given strain for one of the data sets. The approach appears to be very competitive in spite of its simplicity, and is thought to hold considerable promise for e.g. creep modelling of new materials and welds, and when using FEA in creep analysis.
Original languageEnglish
Title of host publicationBALTICA VII - Life Management and Maintenance for Power Plants. Vol. 1
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Pages185-195
ISBN (Electronic)978-951-38-6316-6
ISBN (Print)978-951-38-6315-9
Publication statusPublished - 2007
MoE publication typeB3 Non-refereed article in conference proceedings
EventBALTICA VII - International Conference on Life Management and Main-tenance for Power Plants - Helsinki-Stockholm, Finland
Duration: 12 Jun 200714 Jun 2007

Publication series

NameVTT Symposium
PublisherVTT
Number246
ISSN (Print)0357-9387
ISSN (Electronic)1455-0873

Conference

ConferenceBALTICA VII - International Conference on Life Management and Main-tenance for Power Plants
CountryFinland
CityHelsinki-Stockholm
Period12/06/0714/06/07

Fingerprint

Creep
Logistics
Extrapolation
Boilers
Welds
Turbines
Steam
Pipe
Finite element method
Temperature
Steel

Cite this

Holmström, S., Auerkari, P., & Holdsworth, S. (2007). Predicting creep strain response from rupture data and a robust creep curve model. In BALTICA VII - Life Management and Maintenance for Power Plants. Vol. 1 (pp. 185-195). Espoo: VTT Technical Research Centre of Finland. VTT Symposium, No. 246
Holmström, Stefan ; Auerkari, Pertti ; Holdsworth, Stuart. / Predicting creep strain response from rupture data and a robust creep curve model. BALTICA VII - Life Management and Maintenance for Power Plants. Vol. 1. Espoo : VTT Technical Research Centre of Finland, 2007. pp. 185-195 (VTT Symposium; No. 246).
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abstract = "Creep strain evolution plays a critical role in design and in life assessment of components subjected to service at high temperatures. For instance in turbines, boilers and steam pipes the recommended limits are 1{\%} or 2{\%} of strain. Unfortunately, straightforward engineering methodologies for predicting long term creep strain are not readily available. Robust methods for creep rupture extrapolation have been developed for example in the recommended procedures of the European Creep Collaborative Committee (ECCC) and PD6605 of BSI. The recently developed logistic creep strain prediction (LCSP) model transfers robustness into creep strain modelling. The LCSP model is directly linked to the rupture model and applies a small set of creep curve shape parameters to adjust primary, secondary and tertiary creep properties. The stress and temperature dependence of these shape parameters is optimised by fitting the available strain data. In this work the LCSP model was acquired for P22 steel from a small data set (max 3000 h) together with standard data for time to 1{\%} strain. The model was then used to predict time to strain (0.5 to 5{\%}) for two other P22 data sets using only true time to rupture. The model was also inversely applied to predict time to rupture from values of time to given strain for one of the data sets. The approach appears to be very competitive in spite of its simplicity, and is thought to hold considerable promise for e.g. creep modelling of new materials and welds, and when using FEA in creep analysis.",
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Holmström, S, Auerkari, P & Holdsworth, S 2007, Predicting creep strain response from rupture data and a robust creep curve model. in BALTICA VII - Life Management and Maintenance for Power Plants. Vol. 1. VTT Technical Research Centre of Finland, Espoo, VTT Symposium, no. 246, pp. 185-195, BALTICA VII - International Conference on Life Management and Main-tenance for Power Plants, Helsinki-Stockholm, Finland, 12/06/07.

Predicting creep strain response from rupture data and a robust creep curve model. / Holmström, Stefan; Auerkari, Pertti; Holdsworth, Stuart.

BALTICA VII - Life Management and Maintenance for Power Plants. Vol. 1. Espoo : VTT Technical Research Centre of Finland, 2007. p. 185-195 (VTT Symposium; No. 246).

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

TY - GEN

T1 - Predicting creep strain response from rupture data and a robust creep curve model

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AU - Auerkari, Pertti

AU - Holdsworth, Stuart

PY - 2007

Y1 - 2007

N2 - Creep strain evolution plays a critical role in design and in life assessment of components subjected to service at high temperatures. For instance in turbines, boilers and steam pipes the recommended limits are 1% or 2% of strain. Unfortunately, straightforward engineering methodologies for predicting long term creep strain are not readily available. Robust methods for creep rupture extrapolation have been developed for example in the recommended procedures of the European Creep Collaborative Committee (ECCC) and PD6605 of BSI. The recently developed logistic creep strain prediction (LCSP) model transfers robustness into creep strain modelling. The LCSP model is directly linked to the rupture model and applies a small set of creep curve shape parameters to adjust primary, secondary and tertiary creep properties. The stress and temperature dependence of these shape parameters is optimised by fitting the available strain data. In this work the LCSP model was acquired for P22 steel from a small data set (max 3000 h) together with standard data for time to 1% strain. The model was then used to predict time to strain (0.5 to 5%) for two other P22 data sets using only true time to rupture. The model was also inversely applied to predict time to rupture from values of time to given strain for one of the data sets. The approach appears to be very competitive in spite of its simplicity, and is thought to hold considerable promise for e.g. creep modelling of new materials and welds, and when using FEA in creep analysis.

AB - Creep strain evolution plays a critical role in design and in life assessment of components subjected to service at high temperatures. For instance in turbines, boilers and steam pipes the recommended limits are 1% or 2% of strain. Unfortunately, straightforward engineering methodologies for predicting long term creep strain are not readily available. Robust methods for creep rupture extrapolation have been developed for example in the recommended procedures of the European Creep Collaborative Committee (ECCC) and PD6605 of BSI. The recently developed logistic creep strain prediction (LCSP) model transfers robustness into creep strain modelling. The LCSP model is directly linked to the rupture model and applies a small set of creep curve shape parameters to adjust primary, secondary and tertiary creep properties. The stress and temperature dependence of these shape parameters is optimised by fitting the available strain data. In this work the LCSP model was acquired for P22 steel from a small data set (max 3000 h) together with standard data for time to 1% strain. The model was then used to predict time to strain (0.5 to 5%) for two other P22 data sets using only true time to rupture. The model was also inversely applied to predict time to rupture from values of time to given strain for one of the data sets. The approach appears to be very competitive in spite of its simplicity, and is thought to hold considerable promise for e.g. creep modelling of new materials and welds, and when using FEA in creep analysis.

M3 - Conference article in proceedings

SN - 978-951-38-6315-9

T3 - VTT Symposium

SP - 185

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BT - BALTICA VII - Life Management and Maintenance for Power Plants. Vol. 1

PB - VTT Technical Research Centre of Finland

CY - Espoo

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Holmström S, Auerkari P, Holdsworth S. Predicting creep strain response from rupture data and a robust creep curve model. In BALTICA VII - Life Management and Maintenance for Power Plants. Vol. 1. Espoo: VTT Technical Research Centre of Finland. 2007. p. 185-195. (VTT Symposium; No. 246).