Non-destructive inspection of large structures based on laser-induced plasma shock wave excitation technique and polarization interferometer

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H01279
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 20010:Mechanics and mechatronics-related
• Research Institution: Shibaura Institute of Technology
• Principal Investigator: Hosoya Naoki 芝浦工業大学, 工学部, 教授 (40344957)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: レーザー誘起プラズマ / 衝撃波 / 非破壊検査 / Lamb波 / 偏光干渉計

Outline of Final Research Achievements

Inspectors have demonstrated visual inspection to detect damage or failure of large-scale structures such as aircraft. Therefore, the inspected results vary because of the differences among individuals, resulting in non-cost-effective and time-consuming approaches. The Principal Investigator of this study has been studying the detection of damage to structures using Lamb wave propagation with laser-induced plasma (LIP) shock waves for the input and a scanning laser Doppler vibrometer for the output. This method can provide non-destructive testing (NDT) for a structure with an inspection area of 100 mm × 100 mm square with 2601 points in approximately 40 min, but the inspection time must be less.
In this study, a commercially available high-speed polarization interferometry for the output that can simultaneously measure multipoint vibration responses combined with LIP shock wave excitation for the input was used to visualize Lamb wave propagation in NDT in a shorter measurement time.

Free Research Field

機械力学

Academic Significance and Societal Importance of the Research Achievements

スキャニングレーザードップラー振動計や3軸加速度計を用いた多点計測による振動実験を，本システムで置き換えることができれば，振動実験における工数や費用が低減される．そして，あらゆる機械製品の動的設計の効率化，機械学習を活用するための莫大な計測データの取得にも寄与する．さらに，従来，困難とされてきた非定常応答を面計測できるため，例えば，ハードディスク落下時の耐衝撃性やディスクの空力安定性などの解析にも役立つ．