| 研究課題/領域番号 |
23KF0002
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| 研究種目 |
特別研究員奨励費
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| 配分区分 | 基金 |
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| 応募区分 | 外国 |
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| 審査区分 |
小区分35020:高分子材料関連
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| 研究機関 | 北海道大学 |
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研究代表者 |
グン 剣萍 北海道大学, 先端生命科学研究院, 教授 (20250417)
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| 研究分担者 |
TIAN FUCHENG 北海道大学, 先端生命科学研究院, 外国人特別研究員
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| 研究期間 (年度) |
2023-04-25 – 2025-03-31
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| 研究課題ステータス |
交付 (2023年度)
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| 配分額 *注記 |
2,000千円 (直接経費: 2,000千円)
2024年度: 1,000千円 (直接経費: 1,000千円)
2023年度: 1,000千円 (直接経費: 1,000千円)
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| キーワード | Nonlinear material / Phase field model / Dynamic fracture / Supershear crack |
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| 研究開始時の研究の概要 |
This research will focus on computer simulation, supplemented by experimental research to explore the large deformation dynamic fracture of soft materials, aiming to reveal the physical laws behind the dynamic phenomena of dynamic fracture instability, such as crack bifurcation and oscillation. At the same time, Double Network (DN) gels will be used as an example to explore the special influence of the double network on the fracture dynamics, such as crack path, limit velocity and stability.
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| 研究実績の概要 |
At present, we have developed a dimensionless dynamic phase field model for the fracture of soft materials. Based on this model, we successfully replicated the diverse crack dynamics in quasi-2D soft materials. The captured spontaneous crack oscillations, branching, and the transition from sub-Rayleigh to supershear crack patterns align remarkably well with experimental observations. Categorizing by crack patterns, we constructed crack stability phase diagrams for three different materials, i.e., strain-stiffening, large-strain linear elastic, and strain-softening materials, in a 2D pre-strained fracture scenario. The distinct phase diagrams offer insights into why the intriguing phenomenon of crack oscillation is seldom observed in experiments. The instability wavelength is identified as a bilinear function of nonlinear scale and crack driving force, featuring an intrinsic minimum scale. The onset speed of oscillation scales linearly with the characteristic wave speed near the crack tip. Moreover, our findings also suggest the transition of cracks from sub-Rayleigh to supershear regimes in homogeneous soft materials roots in the increased local wave speed. These findings elucidate the universal laws of nonlinearity in regulating fracture dynamics. The established scaling laws for the supercritical crack oscillation, especially the relation between crack oscillation velocity and local wave speed significantly deepens our understanding of dynamic fracture in soft materials.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
3: やや遅れている
理由
We have successfully completed the tasks outlined in our research plan for the year 2023, and the relevant findings have been compiled into a manuscript currently under review. However, we have encountered some challenges in our work for the year 2024. The large-scale three-dimensional computations of the composite system underway are time-consuming, and suitable boundary conditions have yet to be determined. A significant amount of time is being devoted to testing various boundary conditions. Once an appropriate computational framework is established, subsequent computations are expected to proceed smoothly.
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| 今後の研究の推進方策 |
(1) We plan to develop a three-dimensional toughening model for composite systems. Starting from a simple linear elastic regime and expanding to a nonlinear elastic regime, we aim to utilize this model to elucidate toughening mechanisms in DN gels. Additionally, the developed model holds promise in addressing the stick-slip crack propagation in DN gels.
(2) Our previous work has indicated that crack dynamics are governed by local scales, which significantly deviates from classical fracture theories. In the upcoming research, we endeavor to establish scaling laws for these local scales.
Potential challenges may arise in numerical aspects, particularly in dealing with large-scale, nonlinear computations. We will attempt to address this issue by utilizing the open-source MOOSE framework.
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