1,947 research outputs found
Dataset for 'Investigation of Train-induced Vibration and Noise from a Steel-concrete Composite Railway Bridge Using a Hybrid Finite Element-Statistical Energy Analysis Method'
No full textDataset supports: Quanmin Liu et al (2020). Investigation of Train-induced Vibration and Noise from a Steel-concrete Composite Railway Bridge Using a Hybrid Finite Element-Statistical Energy Analysis Method. Journal of Sound and Vibration</span
Fatigue crack detection by nonlinear spectral correlation with a wideband input
No full textDue to crack-induced nonlinearity, ultrasonic wave can distort, create accompanying harmonics, multiply waves of different frequencies, and, under resonance conditions, change resonance frequencies as a function of driving amplitude. All these nonlinear ultrasonic features have been widely studied and proved capable of detecting fatigue crack at its very early stage. However, in noisy environment, the nonlinear features might be drown in the noise, therefore it is difficult to extract those features using a conventional spectral density function. In this study, nonlinear spectral correlation is defined as a new nonlinear feature, which considers not only nonlinear modulations in ultrasonic waves but also spectral correlation between the nonlinear modulations. The proposed nonlinear feature is associated with the following two advantages: (1) stationary noise in the ultrasonic waves has little effect on nonlinear spectral correlation; and (2) the contrast of nonlinear spectral correlation between damage and intact conditions can be enhanced simply by using a wideband input. To validate the proposed nonlinear feature, micro fatigue cracks are introduced to aluminum plates by repeated tensile loading, and the experiment is conducted using surface-mounted piezoelectric transducers for ultrasonic wave generation and measurement. The experimental results confirm that the nonlinear spectral correlation can successfully detect fatigue crack with a higher sensitivity than the classical nonlinear coefficient
Detection of a Micro-crack on a Rotating Steel Shaft Using Noncontact Ultrasonic Modulation Measurement
No full textDetection of a micro-crack on a rotating structure is limited because conventional non-destructive testing (NDT) is developed based on contact-type transducers. By using air-coupled ultrasonic NDT system, micro-crack detection on a rotating steel shaft is studied. Through air-coupled ultrasonic system, ultrasonic-guided waves at two distinctive frequencies are generated. Then, their ultrasonic modulation at the sum and difference of input frequencies are generated due to micro-crack. Finally, the spectral correlation (SC) of ultrasonic modulation is computed for diagnosis of micro-crack. This is the first study for the detection of a micro-level fatigue crack on a rotating steel shaft using noncontact ultrasonic NDT system. The developed system is experimentally validated using the steel shaft through cyclic loading tests. At each cyclic loading case, the result was compared with conventional penetrant test and metallographic analysis
Motion magnification-based nonlinear ultrasonic signal enhancement and its application to remaining fatigue life estimation of a steel padeye
No full textIn this study, a nonlinear ultrasonic signal enhancement method based on phase-based motion magnification was proposed. First, a two-dimensional (2D) video was constructed from a onedimensional time-domain ultrasonic signal with an automatically selected pixel scale. The constructed 2D video was spatially decomposed into multiple sub-bands with different spatial scales. The subtle motions of the nonlinear responses of interest were enhanced by phase denoising and magnification in each sub-band. Then, the magnified 2D video was reconstructed by collapsing all the amplified sub-bands. Finally, a magnified ultrasonic signal was extracted from the magnified 2D video for further nonlinear ultrasonic analysis. The proposed method was validated with a group of synthetic signals at different noise levels, and applied in the estimation of the remaining fatigue life of a steel padeye with improved accuracy.
Supplemental Material2 - Supplemental material for Biodegradable hybrid mesoporous silica nanoparticles for gene/chemo-synergetic therapy of breast cancer
No full textSupplemental material, Supplemental Material2 for Biodegradable hybrid mesoporous silica nanoparticles for gene/chemo-synergetic therapy of breast cancer by Beibei Zhang, Qi Liu, Mengyuan Liu, Peipei Shi, Lichong Zhu, Lu Zhang and Ruifang Li in Journal of Biomaterials Applications</p
Non-contact visualization of nonlinear ultrasonic modulation for reference-free fatigue crack detection
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