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Experimental and numerical analysis of initial plasticity in P91 steel small punch creep samples

Cortellino, Francesco; Sun, Wei; Rouse, James Paul; Cacciapuoti, B.; Hyde, T.H.

Experimental and numerical analysis of initial plasticity in P91 steel small punch creep samples Thumbnail


Francesco Cortellino

Wei Sun

Assistant Professor

B. Cacciapuoti

T.H. Hyde


To date, the complex behaviour of small punch creep test (SPCT) specimens has not been completely understood, making the test hard to numerically model and the data difficult to interpret. This paper presents a novel numerical model able to generate results that match the experimental findings. For the first time, pre-strained uniaxial creep test data of a P91 steel at 600 °C have been implemented in a conveniently modified Liu and Murakami creep damage model in order to simulate the effects of the initial localised plasticity on the subsequent creep response of a small punch creep test specimen. Finite element (FE) results, in terms of creep displacement rate and time to failure, obtained by the modified Liu and Murakami model are in good agreement with experimental small punch creep test data. The rupture times obtained by the FE calculations which make use of the non-modified creep damage model are one order of magnitude shorter than those obtained by using the modified constitutive model. Although further investigation is needed, this novel approach has confirmed that the effects of initial localised plasticity, taking place in the early stages of small punch creep test, cannot be neglected. The new results, obtained by using the modified constitutive model, show a significant improvement with respect to those obtained by a state of the art creep damage constitutive model (the Liu and Murakami constitutive model) both in terms of minimum load-line displacement rate and time to rupture. The new modelling method will potentially lead to improved capability for SPCT data interpretation

Journal Article Type Article
Acceptance Date Apr 29, 2017
Online Publication Date May 19, 2017
Deposit Date May 3, 2017
Publicly Available Date May 19, 2017
Journal Experimental Mechanics
Print ISSN 0014-4851
Electronic ISSN 1741-2765
Publisher Springer Verlag
Peer Reviewed Peer Reviewed
Volume 57
Issue 8
Keywords Small punch test, Creep, Finite element, Initial plastic strain
Public URL
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