Development of real-time visualization of stress distribution in granular material based on the mechanoluminescence phenomenon

• Project/Area Number: 17K14725
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Geotechnical engineering
• Research Institution: National Institute of Maritime, Port and Aviation Technology
• Principal Investigator: KONDO Akihiko 国立研究開発法人海上・港湾・航空技術研究所, 港湾空港技術研究所, 研究官 (80755893)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000); Fiscal Year 2019: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000); Fiscal Year 2018: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000); Fiscal Year 2017: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
• Keywords: 粒状体 / 可視化 / 応力発光 / 粒子間接触力 / 応力鎖 / 模型実験

Outline of Final Research Achievements

This study aims to develop a new visualization and measurement method of load transmission in granular material based on the mechanoluminescence phenomenon. The mechanoluminescence phenomenon is that emit light in response to mechanical stimulation. Glass beads were coated with a mixture of mechanoluminescent paint and epoxy resin in order to visualize particle level force distribution.
Load tests were conducted on single columns of coated glass particles to calibrate luminance and forces transmitted through the particles and particle contacts. The biaxial loading test were conducted to visualize the load transmission and stress chain in the analog granular material. Moreover, the sum of contact forces deduced from particle luminance is shown to be in agreement with applied boundary loads. The effect of confining pressure and relative density during pile penetration was visualized as an applications to investigate the mechanism of granular material.

Academic Significance and Societal Importance of the Research Achievements

地盤災害の根底にある粒状体の変形・破壊挙動において，ミクロスケールでの粒子間接触力を定量評価することは，マクロな挙動を支配する粒子間の相互作用を解明する際に非常に有用である．既往の研究として，光弾性体を用いた研究やX線回折を用いた手法が挙げられるが，これらの手法は偏光器やシンクロトロンなど高価な設備に加え，粒子形状や材料の制限やトモグラフィに伴う計測間隔の制限がある．そのため，本研究では応力発光現象に着目することで，実際の粒子に塗装することで粒子形状や材料の制限がなく，市販のカメラで安価に粒子間接触力を連続的に観察可能な方法を開発した．

Research Products

• [Int'l Joint Research] Royal Military College of Canada(カナダ)
• [Int'l Joint Research] Royal Military College of Canada(カナダ)
• [Journal Article] Visualization and measurement of load transmission in granular assemblies using mechanoluminescent-coated particles (2019)
  • Author(s): Kondo Akihiko、Takano Daiki、Kohama Eiji、Bathurst Richard J.
  • Journal Title: Granular Matter Volume: 21 Issue: 3 Pages: 1-12
  • DOI: 10.1007/s10035-019-0907-5
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Visualization and measurement of load transmission in granular assemblies using mechanoluminescent-coated particles (2019)
  • Author(s): Akihiko Kondo, Daiki Takano, Eiji Kohama and Richard J. Bathurst
  • Journal Title: Granular Matter Volume: 印刷中
  • Peer Reviewed / Int'l Joint Research
• [Presentation] 応力発光粒子を用いた可視化画像の校正と閉端杭貫入抵抗の可視化 (2020)
  • Author(s): 近藤 明彦, 高野 大樹, 小濱 英司
  • Organizer: 第55 回地盤工学研究発表会
• [Presentation] 応力発光粒子を用いた閉端杭貫入時における先端抵抗の可視化 (2019)
  • Author(s): 近藤 明彦, 高野 大樹, 小濱 英司
  • Organizer: 第54 回地盤工学研究発表会
• [Presentation] Visualization of load transmission during pile penetration in granular material by using elastico-mechanoluminescence particle (2019)
  • Author(s): A. Kondo, D. Takano, E. Kohama
  • Organizer: The VI International Conference on Particle-Based Methods
  • Int'l Joint Research
• [Presentation] 応力発光粒子を用いた粒状体の粒子間接触力分布の可視化 (2018)
  • Author(s): 近藤明彦, 高野大樹, 小濱英司, Richard J. Bathurst
  • Organizer: 第53 回地盤工学研究発表会
• [Presentation] Visualization of load distribution through granular material using mechanoluminescent particles (2017)
  • Author(s): Akihiko Kondo, Daiki Takano, Eiji Kohama, Richard J. Bathurst
  • Organizer: The 3rd International Conference on Mechanoluminescence and Novel Structural Health Diagnosis
  • Int'l Joint Research / Invited