混合モード断裂における螺旋的なクラックフロントの不安定性
1Department of Physics and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts 02115, USA.
Nature
|March 6, 2010
まとめ
混合モードI + IIIの負荷は不安定なクラックセグメンテーションを引き起こし,段階的な破裂表面を形成します. シミュレーションは,指形の子裂け目と予測可能な表面粗さスケールにつながる螺旋的な裂け目の前部変形を明らかにします.
科学分野:
- マテリアルサイエンス 材料科学
- 固体力学 固体力学とは
- 骨折力学 骨折力学とは
背景:
- 純粋な張力下 (モードI) の平面裂けの伝播は,典型的には安定しています.
- 交互に重なった切断張力 (モードIII) は,普遍的に不安定な亀裂の成長につながります.
- 混合モード (I + III) の負荷は,クラックセグメンテーションを引き起こし,槍状のマークを持つ段階的な骨折表面を生成します.
研究 の 目的:
- 混合モードI+III断裂の不安定性の起源を調査する.
- 断片裂の表面粗さスケールを予測する理論を開発する.
- ミックスモードロード下で3Dクラックフロントの進化を理解する.
主な方法:
- 混合モードI + IIIの脆い骨折の大規模シミュレーション.
- 3Dのクラークフロント進化を完全にするために連続的な相場法を使用した.
- 三次元における曲線裂け目の新しい伝播法則を開発した.
主要な成果:
- 平面的な亀裂の伝播は,螺旋形変形に対して線形的に不安定である.
- 螺旋状の変形は,細分化され,指の形をした子裂け目に進化する.
- 非均衡の成長現象と同様の,側面の粗み化が観察されました.
- ストレスバランスと凝結力に基づいて不安定な波長を理論的に推定した.
結論:
- 混合モードI + IIIの負荷は,螺旋的なクラークフロントの変形を通して不安定性を誘発します.
- この研究は,骨折表面の粗さを予測するための理論的枠組みを提供します.
- シミュレーション結果は,側面の回転角度に関する理論的予測と実験データと一致しています.
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