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

Cortellino, Francesco and Sun, Wei and Rouse, James Paul and Cacciapuoti, B. and Hyde, T.H. (2017) Experimental and numerical analysis of initial plasticity in P91 steel small punch creep samples. Experimental Mechanics . ISSN 1741-2765

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Abstract

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

Item Type: Article
Keywords: Small punch test, Creep, Finite element, Initial plastic strain
Schools/Departments: University of Nottingham, UK > Faculty of Engineering > Department of Mechanical, Materials and Manufacturing Engineering
Identification Number: 10.1007/s11340-017-0296-9
Depositing User: Sun, Wei
Date Deposited: 03 May 2017 13:49
Last Modified: 20 Jun 2017 23:20
URI: http://eprints.nottingham.ac.uk/id/eprint/42444

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