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Semi-parametric estimation of the Wilshire creep life prediction model: an application to 2.25Cr-1Mo steel / M. Evans, Mark Evans

Materials Science and Technology, Volume: 35, Issue: 16, Pages: 1977 - 1987

Swansea University Author: Mark Evans

Abstract

The Wilshire equation is a recent addition to the literature on safe life prediction. While the effect of temperature on creep life is reasonably understood, the effect of stress isn’t. The Wilshire equation deals with this by partitioning over sub ranges of stress, but this approximation can lead t...

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Published in: Materials Science and Technology
ISSN: 0267-0836 1743-2847
Published: Informa UK Limited 2019
Online Access: Check full text

URI: https://cronfa.swan.ac.uk/Record/cronfa51494
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Abstract: The Wilshire equation is a recent addition to the literature on safe life prediction. While the effect of temperature on creep life is reasonably understood, the effect of stress isn’t. The Wilshire equation deals with this by partitioning over sub ranges of stress, but this approximation can lead to poor life time predictions. This paper introduces a semi-parametric procedure that allows the data itself to identify the stress relationship. When applied to 2.25Cr-1Mo steel it was found that the stress relationship is non-linear, and this semi-parametric version of the Wilshire model had better predictive performance compared to any partitioned Wilshire model. This approach contains a limit to valid extrapolation and the isothermal predictions for creep life have a more realistic pattern of behaviour.
Keywords: Creep, Arrhenius, Eyring, Wilshire equations, parametric, semi-parametric, non-parametric, activation energy, steel
Issue: 16
Start Page: 1977
End Page: 1987