Mechanism of velocity jump of crack propagation in various soft matters

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K14672
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 13040:Biophysics, chemical physics and soft matter physics-related
• Research Institution: The University of Tokyo
• Principal Investigator: Sakumichi Naoyuki 東京大学, 大学院工学系研究科(工学部), 特任講師 (50635555)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 亀裂進展速度ジャンプ / 破壊力学 / 可解モデル

Outline of Final Research Achievements

We investigated the physics of velocity jumps, i.e., the propagation velocity changes abruptly in a narrow range of the applied load, in the fracture of soft matters. Experiments using various synthetic rubbers and numerical simulations based on continuum mechanics demonstrated the validity of the hypothesis that the velocity jump in rubbers is caused by dynamic glass transition at the crack tip. We also generalized this study to the problem of crack propagation in various viscoelastic sheets and clarified the physics of crack propagation in chemically cross-linked polymer gels and cell sheets used in regenerative medicine.

Free Research Field

高分子物理学

Academic Significance and Societal Importance of the Research Achievements

速度ジャンプは、ゴム、ゲル、樹脂、多孔質材料、生体細胞、地震など、多くのソフトマターで起こる普遍的な現象である。本研究により、ゴムにおいて速度ジャンプが起こるための最小限の要件が明らかになり、ゴム以外の材料における亀裂進展の物理の理解も進んだ。従来の破壊力学は、ハードマターを主な対象としてきたが、本研究はソフトマターを対象とする新しい破壊力学の構築につながる。