Nonlinear Elastic Wave Propagation Behavior in Fiber Reinforced Composites Based on Resonant Scattering Theory

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K14842
• 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: University of Fukui (2021-2022); Kyoto University (2019-2020)
• Principal Investigator: Matsuda Naoki 福井大学, 学術研究院工学系部門, 准教授 (90756818)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 超音波非破壊評価 / 繊維強化複合材料 / 非線形超音波法 / 弾性波散乱問題 / 共鳴散乱理論 / 材料非線形性

Outline of Final Research Achievements

The purpose of this study was to clarify the influence of fiber-matrix delamination and the effect of the matrix resin on the material nonlinearity in fiber-reinforced composites. As a result, we proposed a new theory for the scattered wave of a single fiber with fiber-matrix delamination. We also obtained basic knowledge to evaluate the fiber-matrix delamination from the second-harmonic waves (frequency 2f) generated by an incident wave of a single frequency f. In addition, the mechanical nonlinearity of the matrix resin utilized in the composites was evaluated, and basic data were obtained for understanding the nonlinearity of the composite materials.

Free Research Field

超音波非破壊評価

Academic Significance and Societal Importance of the Research Achievements

繊維強化複合材料の繊維－母材界面でのはく離は強度に大きな影響を与える．また樹脂の劣化は特に繊維強化複合材料を構造材に用いる際の弱点となる圧縮特性への影響が大きい．一方でこうした損傷は，そのスケールが超音波の波長に比べて小さすぎるため，従来の超音波測定では評価が困難であった．これに対し本検討は，材料の非線形な力学的特性に着目する非線形超音波法によるアプローチを試みた．特に本検討では繊維－母材間のはく離と，樹脂そのものが非線形性弾性波伝搬特性に与える影響を明らかにすることで，繊維強化複合材料における非線形特性について基礎的な知見を得た．