Dynamic characteristic evaluation and diagnosis of mechanical/biological systems by non-contact laser excitation system

2018 Fiscal Year Final Research Report

• Project/Area Number: 16H04286
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Dynamics/Control
• Research Institution: Hokkaido University
• Principal Investigator: Kajiwara Itsuro 北海道大学, 工学研究院, 教授 (60224416)
• Co-Investigator(Kenkyū-buntansha): 大橋 俊朗 北海道大学, 工学研究院, 教授 (30270812)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 機械力学・制御 / 振動解析・試験 / 非接触レーザー加振 / 損傷検知 / インパルス応答

Outline of Final Research Achievements

This study developed a health monitoring system for detecting damage on structures. An approach for detecting a hole drilled on a pipe based on laser plasma acoustic excitation and acoustic measurement is included in the results of this study. Non-contact acoustic impulse excitation can be realized by laser-induced plasma and a microphone is used for measuring the time response of acoustic pressure. In this study, we focus on the detection of the hole on the pipe. The time response of acoustic pressure changes due to reflection of acoustic wave caused at the hole drilled on the pipe. The position of the hole is identified by applying continuous wavelet transform to measured time response data with/without the hole. This study demonstrated the effectiveness of the present damage detection method based on the acoustic excitation using the laser-induced plasma.

Free Research Field

機械力学・制御

Academic Significance and Societal Importance of the Research Achievements

本研究で開発した技術は，非接触かつ高周波数帯域の振動計測を可能にするが故，MEMSなどを対象にした振動計測および自動車など実稼働時の計測が要求される分野において，革新的な振動計測技術となることが期待できる．さらに，高周波数帯域での微小な振動特性の変化を捉えることにより，システムの故障や異常を高感度で検知できるヘルスモニタリングシステムの構築が可能になる．本技術はシステム全体の高周波振動計測に基づく検査法であるため，システム全体としての大域的な診断における高感度化および高効率化が達成され，振動実験解析法の発展およびシステムの高信頼化に大きく寄与し，工学的に極めて有用であるといえる．