Single pulse laser excitation of structural vibration using power densities below the surface ablation threshold

Philp, Wayne R.; Booth, David J.; Perry, N. D.

doi:10.1006/jsvi.1995.0406

Cited by 17 publications

(7 citation statements)

References 1 publication

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“…The Nd:YAG laser excitation is suitable for investigations of plate-like structures on running test benches. For large structures, laser pulses with much more energy may be required [23]. Alternatively, piezoelectric shakers or lead zirconate titanate (PZT) patches can be used to achieve high frequency excitation [16] if the test environment does not allow laser excitation.…”

Section: Measurement Setupmentioning

confidence: 99%

“…The resonances are commonly not all sufficiently excited by normal machine operation. Therefore, a nanosecond laser is utilized to introduce very broadband vibration excitations (i.e., significantly over 100 kHz) by laser ablation [21][22][23][24], additionally to the operational excitation. The frequencies of resonances are estimated by using the frequency domain decomposition method, which is successfully deployed in operational modal analysis [25].…”

Section: Introductionmentioning

confidence: 99%

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Non-Contact Damage Detection under Operational Conditions with Multipoint Laservibrometry

Cao

Rembe

2020

Sensors

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Scanning laser–Doppler vibrometry (SLDV) can localize and visualize damages in mechanical structures. In order to enable scanning, it is necessary to repeat the vibration. Therefore, this technique is not suited to detect emerging hazards in working machinery that change the vibration behavior. A common technique for such cases is monitoring the vibration excited by machine operation with accelerometers. This technique requires mechanical coupling between sensors and the measurement object, which influences the high-frequency vibration responses. However, in the low-frequency range, local damages do not shift resonances or distort operational deflection shapes (ODS) significantly. These alterations in the vibration behavior are tiny and hard to detect. This paper shows that multipoint laservibrometry (MPV) with laser excitation can measure these effects efficiently, and it further demonstrates that damages influence ODSs at frequencies above 20 kHz much stronger than at frequencies below 20 kHz. In addition, ODS-based damage indices are discussed; these are highly sensitive to minute visible changes of the ODSs. In order to enhance the sensitivity of hazard detection, the response vector assurance criterion value is computed and evaluated during operation. The capabilities and limitations of the methodology on the example of a cantilever with manually emerging damage are demonstrated.

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Section: Measurement Setupmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Non-Contact Damage Detection under Operational Conditions with Multipoint Laservibrometry

Cao

Rembe

2020

Sensors

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“…レーションにより高周波帯域まで精度の高い周波数応答関数 (FRF)を計測する手法・技術を開発した (6)- (8) ．また，準レーザーアブレーションによる振動実験法として，構造に生じる熱応力を利用して加振力を発生させる方法も検討されている (9) ．このようなレーザー加振技術およびレーザー計測技術を応用することで，振動計測のための加振入力の作用および出力計測がともに非接触化でき，さらに再現性の高い入力が作用させられるので，超小型デバイスに対する振動特性計測の効率および信頼性を向上できる．本論文では，マイクロカンチレバーを振動制御の対象とし，スマート構造化した微小な片持ち梁の制振特性を評価する．マイクロカンチレバーの振動特性評価および振動制御に関して，過去にいくつかの研究がなされている．Mahmoodi (10) らは，非線形性を考慮したマイクロカンチレバーの詳細な振動特性評価を行っている．また， Cunningham (11)…”

Section: 緒言unclassified

Vibration Control Evaluation of Micro Smart Structures with Non-Contact Laser Excitation

Nakamura

Zhu

Kajiwara³

et al. 2011

Trans.JSME(C)

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Smart structures technology that uses piezoelectric element etc. is effective for the vibration control of small devices. However, for micro devices, it is difficult to experimentally measure and evaluate the vibration control characteristics of the system due to its microscopic scale. Namely, it is not realistic to install an external exciter or to apply the excitation force with an impulse hammer. Therefore, in this study, the vibration property is measured and evaluated by using the non-contact excitation/measurement technology using laser ablation for the excitation and laser Doppler vibrometer for the measurement. Since both input excitation and output measurement are made without contact of apparatus and the excitation force has a high reproducibility in the present system, the efficiency and the reliability of the measurement can be improved.

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“…Other relevant studies were carried out by three groups of researches. Philip [8] studied the elastic vibration problem in the single pulse excitation of the structure by laser radiation. Chen [9] calculated the bending angle of laser forming, using FEM by assuming 2-D plane strain and a line shape heating source, and the ÿ-nal deformation predictions were compared with the experimental results.…”

Section: Introductionmentioning

confidence: 99%

Laser-induced vibration during pulsed laser forming

Hsieh

Lin

2004

Optics & Laser Technology

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Single pulse laser excitation of structural vibration using power densities below the surface ablation threshold

Cited by 17 publications

References 1 publication

Non-Contact Damage Detection under Operational Conditions with Multipoint Laservibrometry

Non-Contact Damage Detection under Operational Conditions with Multipoint Laservibrometry

Vibration Control Evaluation of Micro Smart Structures with Non-Contact Laser Excitation

Laser-induced vibration during pulsed laser forming

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