論文 - 田中 昂
-
Detection Method of Contact-Type Failure Based on Nonlinear Wave Modulation Utilizing Ultrasonic Vibration Driven by Self-excitation 査読
Tanaka T., Oura Y., Maeda S.
Smart Innovation, Systems and Technologies 166 79 - 89 2020年1月
詳細を見る
記述言語：英語 掲載種別：研究論文（学術雑誌） 出版者・発行元：Smart Innovation, Systems and Technologies 参加形態：共同（主担当）
© 2020, Springer Nature Switzerland AG. This paper introduces the concept of new detection method of contact-type failure based on nonlinear wave modulation utilizing ultrasonic vibration driven by self-excitation. It is difficult to detect the contact-type failure in standard inspection utilizing linear ultrasonic vibration. The constructional element of infrastructure is excited by environmental disturbance or forced excitation. In this situation, the contact condition of the failure fluctuates in synchronization with vibration. As this result, local stiffness in the vicinity of failure location fluctuates at the vibration frequency. Thereby, the amplitude and phase of ultrasonic vibration are modulated caused by local stiffness fluctuation (nonlinear wave modulation). This phenomenon can be expressed by a linear time-varying system caused by fluctuation of the natural frequency. In this paper, the new detection method of contact-type failure utilizing self-excited ultrasonic vibration is introduced. Firstly, the concept of detection method of contact-type damage based on nonlinear wave modulation is proposed. It is indicated from time history response analysis using single degree-of-freedom model of nonlinear wave modulation that the fluctuation amplitude of the amplitude and phase of ultrasonic as failure index varies depending on viscous damping. Secondly, the self-excited method utilizing local feedback control and characteristics are introduced. This method realizes oscillator which start to oscillate at the natural frequency automatically. Thus, the frequency of oscillation signal controlled by local feedback control is fluctuated in synchronization with fluctuation of natural frequency when nonlinear wave modulation occurred. Lastly, it is proved that the fluctuation amplitude of frequency of oscillation signal is the failure index independent of viscous damping.
DOI： 10.1007/978-3-030-57745-2_8
その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85091270496&origin=inward
-
局所フィードバック制御を用いた分散制御による音響空間の固有振動の計測 査読
田中 昂，栗田 裕，大浦 靖典， 中村 寛望
日本機械学会論文集 85 ( 874 ) 2019年6月
詳細を見る
記述言語：日本語 掲載種別：研究論文（学術雑誌） 出版者・発行元：日本機械学会 参加形態：共同（主担当）
Natural vibrations of acoustic space expand noise. Measurement of natural vibration is effective to reduce noise based on noise generation mechanism. Acoustic space has many natural vibrations in the noise frequency band. Multi-point excitation is useful for measuring natural vibration, which has mixed modes and high damping. Furthermore, it is necessary to cancel the influence of dumping to excite the modes individually. In this study, the new measurement principle of natural vibrations of acoustic space by multi-point excitation using decentralized control with local feedback control is proposed. An excitation system with local feedback control excites natural vibration without frequency adjustment and cancels damping in acoustic space. Excitation systems with decentralized control can have multi-point excitation without any adjustment of amplitude and phase each other. The proposed acoustic excitation system consists of a speaker, a microphone and a local feedback controller. The controller generates negative damping according to the sound pressure detected by the microphone and feeds it to the speaker. Firstly, it is confirmed that one acoustic excitation system is self-excited at resonance frequency and some resonance peak of the transfer function is sharpened by canceling the effect of damping. Secondly, multi-point excitation using decentralized control using four acoustic excitation systems is performed to excite many modes. All supposed modes are excited without adjustment of the excitation systems according to mode such as amplitude and phase. Finally, it is confirmed that acoustic excitation system has no limitation on the number of installations and has extensibility for higher-order mode excitation.
-
MEASUREMENT OF NATURAL VIBRATION OF ACOUSTIC SPACE BY MULTI-POINT EXCITATION USING DECENTRALIZED CONTROL 査読
Tanaka Takashi, Nakamura Hiromu, Oura Yasunori, Kurita Yutaka
Proceedings of 25th International Congress on Sound and Vibration 2018年7月
詳細を見る
記述言語：英語 掲載種別：研究論文（国際会議プロシーディングス） 参加形態：共同（主担当）
Natural vibrations of acoustic space expand noise. To reduce noise based on mechanism, measurements of natural vibration is effective. Acoustic space has many natural vibrations with damping
in the noise frequency band. Multi-point excitation is useful for measuring natural vibration,
which has mixed modes. Furthermore, it is necessary to cancel the influence of dumping to excite the modes individually. In this study, the measurement technique of natural vibrations of
acoustic space by multi-point excitation using decentralized control with local feedback control
is proposed. An excitation system with local feedback control excites natural vibration without
frequency adjustment and cancels damping in acoustic space. Excitation systems with decentralized control can have multi-point excitation without any adjustment of phase and amplitude each
other. The acoustic excitation system consists of a speaker, a microphone and a local feedback
controller. The controller generates negative damping according to the sound pressure detected
by the microphone and feeds it to the speaker. Firstly, it is confirmed that one acoustic excitation
system is self-oscillate at resonance frequency and some resonance peak of the transfer function
is sharpened by canceling the effect of damping. Secondly, to excite many modes, multi-point
excitation using decentralized control is performed using four acoustic excitation systems. All
supposed modes are excited without adjustment of the excitation systems according to mode such
as amplitude and phase. Finally, it is confirmed that acoustic excitation system has no limitation
on the number of installations and has extensibility for higher-order mode excitation. -
Detection of Adhesive Failures via Nonlinear Piezoelectric Impedance Modulation 査読
Arata Masuda, Akane Akisada, Takashi Tanaka, Akira Sone
Proceedings of the 12th International Conference on Motion and Vibration Control 2014年8月
詳細を見る
記述言語：英語 掲載種別：研究論文（国際会議プロシーディングス） 参加形態：共同（副担当）
This study concerns adhesive failure detection of bonded joint in a structure by utilizing a sensitive baseline-free structural health monitoring methodology referred to as nonlinear piezoelectric impedance modulation method. According to the progress of adhesion technologies, adhesion joints have been used more often replacing conventional mechanical joints such as bolted and riveted joints. Thus, a nondestructive technique, which can detect and monitor the development of adhesive failures in-situ to investigate the health state of adhesive joints would be required. This technique evaluates failures in the structure under the pump excitation at low frequency, by demodulating the current response in amplitude and phase when a PZT patch on the surface is driven by a high frequency probe voltage source. It has distinctive features of being sensitive to incipient defects inside the structure and theoretically baseline-free because no modulation exists in a structure, which has no defect. In this study, thin plate specimens with bonded parts in healthy and incomplete conditions are subjected to the probe and pump excitations, and the resultant damage evaluation indices are investigated in terms of the probe and pump amplitudes.
-
Integrity Diagnosis Method of Bolted Joint Based on Time Fluctuation of Reflection Intensity Caused by Nonlinear Wave Modulation 査読
Takashi Tanaka, Arata Masuda, Akira Sone
Proceedings of the ASME 2014 International Design & Engineering Technical Conference and Computers & Information in Engineering Conference 2014年8月
詳細を見る
記述言語：英語 掲載種別：研究論文（国際会議プロシーディングス） 参加形態：共同（主担当）
This study presents the integrity diagnosis method of the bolted joint based on nonlinear wave modulation. When the structure that has the contact interface is vibrating at low-frequency, the contact interface is tapping and clapping due to low-frequency vibration. In this condition, the scatter characteristics, such as wave transmissivity and reflectivity, of high-frequency waves in vicinity of the contact interface are fluctuated in synchronization with low-frequency excitation because of the contact acoustic nonlinearity. The time fluctuation of reflection intensity, which expresses the reflectivity in the specific location, of high-frequency waves at the contact interface is given as the reflection intensity map which plots time-spatial map. In this paper, experiment using the beam specimen which has single bolted joint is conducted to examine the performance of the evaluation index based on the fluctuation amplitude of reflection intensity.
-
Localization of Contact-Type Failure in Beam Structure Based on Reflectivity Modulation 査読
Takashi Tanaka, Arata Masuda, Akira Sone
Proceedings of the 12th International Conference on Motion and Vibration Control 2014年8月
詳細を見る
記述言語：英語 掲載種別：研究論文（国際会議プロシーディングス） 参加形態：共同（主担当）
This study presents the detection and localization method of contact-type failure based on the reflectivity modulation which is the reflectivity fluctuation caused by nonlinear wave modulation. When the structure including contact-type failure, such as fatigue crack, delamination of composite material and bolt loosening, is vibrating at low-frequency, the contact interfaces are breathing due to low-frequency vibration. Then, the scatter characteristics of high-frequency waves, such as wave transmisivirity and reflectivity, in the vicinity of the contact-type failure are fluctuated in synchronization with low-frequency vibration. The fluctuation of the reflection intensity of high-frequency waves which expresses the reflectivity in the specific location is given at the location of the contact-type failure. So, the time-spatial map of the reflection intensity can figure out the location of contact-type failure as the reflectivity fluctuation point. Especially, in this paper, the theory of some contact-type failures detection based on the reflection intensity fluctuation caused by nonlinear wave modulation is proposed, and investigated for a beam specimen which has some simulated contact-type failures experimentally.
-
インパクトハンマ加振を受けるはりにおける非線形波動変調現象に基づく損傷位置の推定 査読
田中 昂，増田 新，曽根 彰
日本機械学会論文集（C編） 79 ( 801 ) 1594 - 1601 2013年5月
詳細を見る
記述言語：日本語 掲載種別：研究論文（学術雑誌） 参加形態：共同（主担当）
This paper concerns the estimation method of damage location based on the nonlinear wave modulation demodulation which has attracted much attention in the field of structural health monitoring. When a structure containing a contact-type damage is subjected to a low-frequency vibration, a high-frequency wave which propagates through the damage may undergo amplitude and phase modulation at the damage location because the scatter characteristics of high-frequency waves in the vicinity of the damage may fluctuate in synchronization with the low-frequency vibration because of the contact acoustic nonlinearity. Since this modulation propagates through the structure with the group velocity, it may be possible to estimte damage location by measuring the modulation and performing an inverse analysis based on the wave propagation model. In this paper, a mathematical model of the modulation propagation on a Timoshenko beam is constructed, and by considering the damage as a source of the modulation, an estimation algorithm of damage location which utilizes the time difference between the modulated waves measured by sensor arrays located at both sides of the damage is proposed, and examined experimentally.