Construction of guiding principles of materials design for tough rubbers

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K14839
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 18010:Mechanics of materials and materials-related
• Research Institution: The University of Tokyo
• Principal Investigator: Kubo Atsushi 東京大学, 生産技術研究所, 助教 (40760335)
• Project Period (FY): 2019-04-01 – 2021-03-31
• Keywords: ゴム / 破壊力学 / き裂進展 / 有限要素法

Outline of Final Research Achievements

We conducted a series of finite element method (FEM) analyses and mathematical-model analyses for the purpose of revealing the mechanism of the “velocity transition” phenomenon in crack propagation (an abrupt acceleration of crack propagation beyond a critical external load) in rubber-like materials. The FEM simulation of crack propagation were performed to obtain the relationship between the known material parameters (e.g., elasticity, viscosity) and the transition energy (i.e., the critical tearing energy to induce the velocity transition). A series of FEM simulations with systematically varied material parameters revealed the determining factors for the transition energy. A mathematical model was constructed on the basis of the FEM results, where the transition energy was estimated as a function of the mechanical state at the crack tip.

Free Research Field

材料力学

Academic Significance and Societal Importance of the Research Achievements

き裂進展速度転移現象はゴム材料の寿命と非常に密接に関連しており，速度転移を引き起こす「転移エネルギー」が大きいほどき裂が進展しにくく，疲労や摩耗に強いということが知られている．つまり転移エネルギーの大きいゴム材料を開発すれば，製品の強靭化・長寿命化が実現できる．本研究では，弾性や粘性といった既知の力学パラメータと転移エネルギーの関係を明らかにした．本研究の成果により，転移エネルギーを向上する（つまり，ゴム材料を強靭化する）ための材料設計指針が得られ，材料開発における大幅なコスト削減および製品の長寿命化による環境負荷の低減などの効果が期待される．