クラック先の局所的な超弾性性による動的骨折の不安定性
Markus J Buehler1, Huajian Gao
1Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Room 1-272, Cambridge, Massachusetts 02139, USA. mbuehler@MIT.EDU
Nature
|January 20, 2006
まとめ
脆い材料のダイナミックな不安定性は,割れ目の速度が増加するにつれて,割れ目の表面が粗くなることを引き起こします. 超弾力性,または非線形ストレス-ストレスの行動は,この不安定性を支配し,裂け目の拡散現象を説明します.
科学分野:
- 固体力学 固体力学とは
- マテリアルサイエンス 材料科学
- 計算物理学の物理
背景:
- 脆い材料における亀裂の伝播は,表面の粗化につながるダイナミックな不安定性を示します.
- 観測された現象には,鏡,霧,ハックルの割れ目の表面が,割れ目の速度が増加するなどがある.
- 既存の骨折理論では,クラック先の近くの非線形ストレス-ストレスの関係 (超弾性) をしばしば見過ごしている.
研究 の 目的:
- クラックの拡散中の動的不安定性の発生における超弾性性の役割を調査する.
- クラックの不安定性を制御するメカニズムの競争を説明する一般的なモデルを開発する.
- 骨折力学の議論の多い実験的および計算的発見に関する洞察を提供すること.
主な方法:
- 大幅に並行して大規模な原子模擬を活用した.
- 線形弾性から非線形行動への移行を可能にする材料モデルを使用した.
- クラックの不安定性の発生に関する一般的なモデルを開発した.
主要な成果:
- 超弾性性が動的不安定性の発生を左右する要因であることを実証した.
- 不安定の発生を,ストレスフィールドとエネルギーフローメカニズムとの競争として識別した.
- シミュレーションにより,不安定性がダイナミックな骨折に固有のものであることが明らかになった.
結論:
- 超弾性性は,クラック伝播の不安定性を理解するために重要である.
- 一般化されたモデルは,骨折表面形態論を分析するための枠組みを提供します.
- 発見は,脆い骨折における異なった実験的および計算的観測を調和させる.
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