Campus Units

Aerospace Engineering, Chemical and Biological Engineering, Materials Science and Engineering, Mechanical Engineering, Physics and Astronomy, Ames Laboratory

Document Type

Article

Publication Version

Published Version

Publication Date

8-4-2020

Journal or Book Title

npj Computational Materials

Volume

6

Issue

1

First Page

115

DOI

10.1038/s41524-020-00382-8

Abstract

Materials under complex loading develop large strains and often phase transformation via an elastic instability, as observed in both simple and complex systems. Here, we represent a material (exemplified for Si I) under large Lagrangian strains within a continuum description by a 5th-order elastic energy found by minimizing error relative to density functional theory (DFT) results. The Cauchy stress—Lagrangian strain curves for arbitrary complex loadings are in excellent correspondence with DFT results, including the elastic instability driving the Si I → II phase transformation (PT) and the shear instabilities. PT conditions for Si I → II under action of cubic axial stresses are linear in Cauchy stresses in agreement with DFT predictions. Such continuum elastic energy permits study of elastic instabilities and orientational dependence leading to different PTs, slip, twinning, or fracture, providing a fundamental basis for continuum physics simulations of crystal behavior under extreme loading.

Comments

This article is published as Chen, Hao, Nikolai A. Zarkevich, Valery I. Levitas, Duane D. Johnson, and Xiancheng Zhang. "Fifth-degree elastic energy for predictive continuum stress–strain relations and elastic instabilities under large strain and complex loading in silicon." npj Computational Materials 6, no. 1 (2020): 115. DOI: 10.1038/s41524-020-00382-8. Posted with permission.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

Copyright Owner

The Author(s)

Language

en

File Format

application/pdf

Share

COinS