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Initiation of kink-band failure of a unidirectional CFRP due to microscale fiber undulation

Research Project

Project/Area Number 20K04184
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Review Section Basic Section 18010:Mechanics of materials and materials-related
Research InstitutionNihon University

Principal Investigator

UEDA Masahito  日本大学, 理工学部, 准教授 (80434116)

Project Period (FY) 2020-04-01 – 2023-03-31
Project Status Completed (Fiscal Year 2022)
Budget Amount *help
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2022: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2021: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2020: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Keywords炭素繊維強化プラスチック / 圧縮強度 / キンクバンド / キンクバンド破壊 / 繊維うねり / デジタルツイン / X線CT
Outline of Research at the Start

炭素繊維強化プラスチック(CFRP)は金属よりも軽量かつ高剛性・高強度な材料であるが,その圧縮強度は引張強度と比較して低いため,曲げを受ける部材では圧縮側から先行して破壊が生じやすい.CFRPの圧縮強度は炭素繊維の配列状況に依存すると考えられるが,その詳細な配列状況は不明である.本研究ではX線断層撮影装置を用いてCFRPの断層画像を取得し,各繊維の揺らぎを再現するCFRPの3次元モデルを構築して,その数値シミュレーションを行う.炭素繊維のミクロンオーダーの揺らぎを考慮に入れて,CFRPの圧縮強度の発現メカニズムを評価することによって,圧縮強度を向上させるための方法を究明することを目的とする.

Outline of Final Research Achievements

The microscale fiber fluctuations in a unidirectional carbon fiber reinforced plastic (UD CFRP) are the main cause of the low compressive strength in the fiber direction. However, the origin of the longitudinal compressive failure i.e., kink band failure in the microscale fiber fluctuations has not been clarified. In this study, the compressive strength was predicted considering the variability of the fiber misalignment angle. All fibers supported a compressive load in the initial loading. The fibers progressively declined their load-bearing capability in descending order of the misalignment angle with an increase in compressive loading. The fibers with a misalignment angle of 0.5 degree or smaller showed a large load drop after their maximum loading, which triggered the ultimate failure. It was shown that the variability of the fiber misalignment angle was indispensable to determining the axial compressive strength of the UD CFRP.

Academic Significance and Societal Importance of the Research Achievements

炭素繊維強化プラスチック(CFRP)の繊維方向圧縮強度は繊維方向引張強度の50~60%程度であり.曲げを受ける構造部材として使用する場合には圧縮側の補強が必要となる.従って,圧縮強度が向上すれば,CFRP構造の更なる軽量化を実現することができる.本研究では,マイクロスケールの繊維揺らぎを考慮に入れた一方向CFRPの圧縮強度予測方法を確立することによって,圧縮強度を決定している繊維揺らぎを特定した.また,繊維初期不整角のばらつきが圧縮強度に与える影響を評価した.以上により,一方向CFRPの繊維揺らぎを抑制した場合の圧縮強度の向上率を定量的に評価することができるようになった.

Report

(4 results)
  • 2022 Annual Research Report   Final Research Report ( PDF )
  • 2021 Research-status Report
  • 2020 Research-status Report
  • Research Products

    (5 results)

All 2022 2021 2020

All Journal Article (1 results) (of which Peer Reviewed: 1 results,  Open Access: 1 results) Presentation (4 results) (of which Int'l Joint Research: 2 results)

  • [Journal Article] Initiation and propagation of fiber kinking from fiber undulation in a unidirectional carbon fiber reinforced plastic2020

    • Author(s)
      Takahashi Takuya、Ueda Masahito、Miyoshi Keisuke、Todoroki Akira
    • Journal Title

      Composites Part C: Open Access

      Volume: 3 Pages: 100056-100056

    • DOI

      10.1016/j.jcomc.2020.100056

    • Related Report
      2020 Research-status Report
    • Peer Reviewed / Open Access
  • [Presentation] 繊維方向圧縮強度に与える界面強度の影響2022

    • Author(s)
      上田政人
    • Organizer
      日本界面学会2022年度年次大会
    • Related Report
      2022 Annual Research Report
  • [Presentation] X-ray computed tomography-based automatic fiber tracking of unidirectional carbon fiber reinforced plastic by digital image correlation method2021

    • Author(s)
      Shiryu Morita,Masahito Ueda
    • Organizer
      17th Japan International SAMPE Symposium & Exhibition
    • Related Report
      2021 Research-status Report
    • Int'l Joint Research
  • [Presentation] Fiber kinking of unidirectional CFRP with clustered fiber arrangement2021

    • Author(s)
      Takuya Takahashi, Akira Todoroki, Masahito Ueda
    • Organizer
      17th Japan International SAMPE Symposium & Exhibition
    • Related Report
      2021 Research-status Report
    • Int'l Joint Research
  • [Presentation] アップデートデジタル画像相関法を用いた一方向炭素繊維強プラスチック内部の繊維うねりの評価2021

    • Author(s)
      森田子竜, 上田政人
    • Organizer
      日本非破壊検査協会 安全・安心な社会を築く先進材料・非破壊計測技術ミニシンポジウム
    • Related Report
      2020 Research-status Report

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Published: 2020-04-28   Modified: 2024-01-30  

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