Size effects in a power law creeping layer under compression or shear, and implications for deformation mechanisms of lithium films

Alessandro Leronni; Vikram S. Deshpande; Norman A. Fleck

doi:10.1016/j.jmps.2023.105505

Size effects in a power law creeping layer under compression or shear, and implications for deformation mechanisms of lithium films

Alessandro Leronni, Vikram S. Deshpande, Norman A. Fleck

Research output: Contribution to journal › Article › peer-review

1 Citation (SciVal)

Abstract

The axisymmetric compression of a power law creeping metallic sandwich layer of micron-scale thickness is analysed. Account is taken of the elevation in flow strength due to the presence of a spatial gradient in plastic strain rate. Numerical and analytical solutions reveal that the average compressive traction is enhanced by a combination of strain rate gradients and plastic constraint. A similar size effect is predicted for simple shear of the creeping sandwich layer. The difference in responses for compression and shear is traced to the different profiles of shear strain rate through the thickness of the layer. The sensitivity of compressive and shear strengths to the choice of higher-order boundary condition is explored, and good agreement with recent experiments on compression and shear of a thin sandwich layer of lithium is achieved by assuming fully clamped higher-order boundary conditions and a material length scale on the order of 3−5μm in the strain gradient-based creep theory.

Original language	English
Article number	105505
Journal	Journal of the Mechanics and Physics of Solids
Volume	183
Early online date	7 Dec 2023
DOIs	https://doi.org/10.1016/j.jmps.2023.105505
Publication status	Published - 1 Feb 2024

Data Availability Statement

Data will be made available on request.

Funding

This work was aided by the Faraday Institution (UK) projects “FutureCat” with grant no. FIRG017 and “Degradation” under grant no. FIRG001 and FIRG024 . The authors are also grateful for support from the European Research Council project MULTILAT, with grant no. 669764 . The authors are grateful to Dr. Joe Stallard of Cambridge University Engineering Department for useful discussions and access to his published data.

Funders	Funder number
The Faraday Institution	FIRG024, FIRG001, FIRG017
European Research Council	669764

Keywords

Creep
Dislocations
Metallic materials
Strain gradient plasticity
Strengthening and mechanisms

ASJC Scopus subject areas

Condensed Matter Physics
Mechanics of Materials
Mechanical Engineering

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10.1016/j.jmps.2023.105505Licence: CC BY

Cite this

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abstract = "The axisymmetric compression of a power law creeping metallic sandwich layer of micron-scale thickness is analysed. Account is taken of the elevation in flow strength due to the presence of a spatial gradient in plastic strain rate. Numerical and analytical solutions reveal that the average compressive traction is enhanced by a combination of strain rate gradients and plastic constraint. A similar size effect is predicted for simple shear of the creeping sandwich layer. The difference in responses for compression and shear is traced to the different profiles of shear strain rate through the thickness of the layer. The sensitivity of compressive and shear strengths to the choice of higher-order boundary condition is explored, and good agreement with recent experiments on compression and shear of a thin sandwich layer of lithium is achieved by assuming fully clamped higher-order boundary conditions and a material length scale on the order of 3−5μm in the strain gradient-based creep theory.",

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Size effects in a power law creeping layer under compression or shear, and implications for deformation mechanisms of lithium films

Abstract

Data Availability Statement

Funding

Keywords

ASJC Scopus subject areas

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