Nondestructive image analysis of drying stress in wood with air-coupled ultrasonic

• Project/Area Number: 17K06645
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Building structures/Materials
• Research Institution: Kyushu University
• Principal Investigator: Hasegawa Masumi 九州大学, 農学研究院, 助教 (00372756)
• Co-Investigator(Kenkyū-buntansha): 岡村 博幸 福岡県工業技術センター, その他部局等, 研究員 (80502244)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000); Fiscal Year 2019: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000); Fiscal Year 2018: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000); Fiscal Year 2017: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
• Keywords: 非破壊評価 / 空中超音波 / 表面波 / 音弾性 / 木材 / 非接触 / 応力測定 / 伝搬速度 / 乾燥応力 / 音弾性定数 / 構造材料 / 木質材料 / 超音波 / 応力解析

Outline of Final Research Achievements

The final objective is to establish the non-contact and non-destructive technique of drying stress in lumber by surface wave generated using air-coupled ultrasonic. The optimal incident angle was determined. Effect of knots on the propagation of surface wave was observed with micro focus X-ray CT device. Surface wave was generated on the surface of wood under tensile stress. Surface wave velocity linearly changed with tensile stress. The acoustoelastic constants were determined. These findings suggested that it is possible to measure the drying stress with air-coupled ultrasonic.

Academic Significance and Societal Importance of the Research Achievements

本研究では木材表面を伝搬する表面波の伝搬速度は引張応力に対してリニアに変化することが明らかになった。これは伝搬速度の変化を測定することで木材表面の応力状態が予測できることを示唆するものであり，木材の乾燥応力の非破壊測定につながる学術的・社会的に意義のある研究成果である。本研究を更に継続していくことで空中超音波を利用した木材の乾燥応力の非破壊測イメージング解析システムの開発が可能になると考えられる。

Research Products

• [Presentation] Effect of tensile stress on velocity of surface wave generated using air-coupled ultrasonic sensor (2019)
  • Author(s): Masumi Hasegawa, Hiroyuki Okamura, Kazutoshi Takeuchi, Junji Matsumura
  • Organizer: 21st International Nondestructive Testing and Evaluation of Wood Symposium
  • Int'l Joint Research
• [Presentation] 表面波音弾性法による木材の乾燥応力測定に向けての基礎的研究 (2019)
  • Author(s): 長谷川益己
  • Organizer: 第26回超音波による非破壊評価シンポジウム
• [Presentation] Effect of Tensile Stress on Velocity of Surface Wave Generated Using Air-coupled Ultrasonic Sensor (2019)
  • Author(s): Masumi Hasegawa
  • Organizer: 21st International Nondestructive Testing and Evaluation of Wood Symposium
  • Int'l Joint Research
• [Presentation] Propagation Properties of Surface Wave Generated on Wood (2018)
  • Author(s): Masumi Hasegawa
  • Organizer: The Sixth Japan-US Symposium Emerging NDE Capabilities for a Safer World(国際学会)
  • Int'l Joint Research
• [Presentation] Propagation Properties of Surface Wave Generated on Wood (2018)
  • Author(s): Masumi Hasegawa
  • Organizer: The Sixth Japan-US Symposium Emerging NDE Capabilities for a Safer World
  • Int'l Joint Research