Vibration testing based on impulse response excited by pulsed-laser ablation: Measurement of frequency response function with detection-free input

Hosoya, Naoki; Kajiwara, Itsuro; Hosokawa, Takahiko

doi:10.1016/j.jsv.2011.10.034

Cited by 39 publications

(33 citation statements)

References 5 publications

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“…The experiment was conducted at room temperature. In previous studies, 32,33,37,38 we demonstrated the validation of LA excitation force for vibration or acoustic tests. Newton's second law of motion can evaluate the magnitude and frequency characteristics of excitation force using the following protocol.…”

Section: Methodsmentioning

confidence: 96%

“…F(ω) should be constant and we have verified that F(ω) is totally flat within the target frequency region below 40 kHz. 33 Because the excitation force F (N) is a frequency-independent scalar value, we can obtain excitation force F by averaging F(ω) over the target frequency region. In the previous experiment, 33 when laser fluence was set at 49.2 GW/mm 2 , we obtained the magnitude of excitation force of 3.59 mN and the totally flat excitation component up to the frequency region of 40 kHz.…”

Section: Methodsmentioning

confidence: 99%

“…LA has various applications, including plasma growth, 23 LA shockwave in air, 24 LA in water, 25 cavitation bubble, 26 laser propulsion, 27,28 laser micromachining, 29 laser deposition, 30 laser peening, 31 and vibration tests and acoustic tests using LA or laser-induced breakdown (LIB). [32][33][34][35][36][37][38][39][40][41] Although multiple stress waves in silica glass generated by femtosecond LA 20 have been visualized using the shadowgraph technique, using LA as an excitation force for gels has yet to be investigated.…”

Section: Introductionmentioning

confidence: 99%

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High spatial and temporal resolution measurement of mechanical properties in hydrogels by non-contact laser excitation

et al. 2016

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Gels have received increased attention as potential materials for biological materials because they can exhibit similar mechanical properties. One obstacle for using gels is that their mechanical properties are significantly altered by defects, such as an inhomogeneous crosslink density distribution. If these defects could be detected and the values and spatial distributions of mechanical properties in the gel could be determined, it would be possible to apply gels for several fields. To achieve the high spatial and temporal resolution measurement of mechanical properties in hydrogels, in our method, a conventional contact excitation device is replaced with a non-contact excitation using laser ablation for the input and magnetic resonance elastography to measure stress waves is replaced with the Schlieren method with a high-speed camera. Magnetic resonance elastography is a local measurement technique, and consequently, requires a lot of time to characterize a sample, as well as does not have sufficient spatial resolution to obtain a broad range of elasticity coefficients of gels. We use laser ablation to apply non-contact impulse excitations to gels to generate stress waves inside them. We can determine mechanical properties of gels using the stress waves’ propagation velocity.

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Section: Methodsmentioning

confidence: 96%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High spatial and temporal resolution measurement of mechanical properties in hydrogels by non-contact laser excitation

et al. 2016

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“…This allows the conclusion that using laser excitation to excite membrane structure in vibration testing is appropriate, because vibration testing using laser excitation provides the high frequency vibration data [6,[13][14][15][16].…”

Section: Damage Detection For Single Damage On Membranementioning

confidence: 99%

Damage detection in membrane structures using non-contact laser excitation and wavelet transformation

Huda

Kajiwara

Hosoya

2014

Journal of Sound and Vibration

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Abstract:In this paper, a vibration testing and health monitoring system based on an impulse response excited by laser is proposed to detect damage in membrane structures. A high power Nd: YAG pulse laser is used to supply an ideal impulse to a membrane structure by generating shock waves via laser-induced breakdown in air. A health monitoring apparatus is developed with this vibration testing system and a damage detecting algorithm which only requires the vibration mode shape of the damaged membrane. Artificial damage is induced in membrane structure by cutting and tearing the membrane. The vibration mode shapes of the membrane structure extracted from vibration testing by using the laser-induced breakdown and laser Doppler vibrometer are then analyzed by 2-D continuous wavelet transformation. The location of damage is determined by the dominant peak of the wavelet coefficient which can be seen clearly by applying a boundary treatment and the concept of an iso-surface to the 2-D wavelet coefficient. The applicability of the present approach is verified by finite element analysis and experimental results, demonstrating the ability of the method to detect and identify the positions of damage induced on the membrane structure.

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“…These issues have led to research into non-contact excitation methods with better reproducibility. Vibration measurement systems using non-contact laser excitation can guarantee a very high degree of measurement reproducibility [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Bolt loosening analysis and diagnosis by non-contact laser excitation vibration tests

Huda

Kajiwara

Hosoya

et al. 2013

Mechanical Systems and Signal Processing

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102

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Vibration testing based on impulse response excited by pulsed-laser ablation: Measurement of frequency response function with detection-free input

Cited by 39 publications

References 5 publications

High spatial and temporal resolution measurement of mechanical properties in hydrogels by non-contact laser excitation

High spatial and temporal resolution measurement of mechanical properties in hydrogels by non-contact laser excitation

Damage detection in membrane structures using non-contact laser excitation and wavelet transformation

Bolt loosening analysis and diagnosis by non-contact laser excitation vibration tests

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