Concrete Sub-Surface Crack Characterization by Means of Surface Rayleigh Wave Method

2019 ◽  
Vol 116 (1) ◽  
Author(s):  
Foo Wei Lee ◽  
Hwa Kian Chai ◽  
Kok Sing Lim ◽  
See Hung Lau
Keyword(s):  
Rayleigh Wave ◽  
Surface Crack ◽  
Wave Method ◽  
Surface Rayleigh Wave

scholarly journals An Approach to Size Sub-Wavelength Surface Crack Measurements Using Rayleigh Waves Based on Laser Ultrasounds

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5077
Author(s):  
Haiyang Li ◽  
Qianghua Pan ◽  
Xiaotong Zhang ◽  
Zhiwu An
Keyword(s):  
Theoretical Analysis ◽  
Rayleigh Wave ◽  
Surface Crack ◽  
Rayleigh Waves ◽  
Critical Frequency ◽  
Experimental Results ◽  
Notch Depth ◽  
Frequency Method ◽  
Threshold Phenomenon ◽  
Sub Wavelength

In this paper, the interaction of a broadband Rayleigh wave generated by a laser and an artificial rectangular notch is analyzed theoretically and experimentally. For the theoretical analysis, a Gaussian function is adopted to analyze the modulation of notch depth on the frequency spectrum via reflection and transmission coefficients. By the finite element method, the Rayleigh wave generated by pulsed laser beam irradiation and its scattering waves at cracks are calculated. A curve with a slope close to 4 fitted by crack depth and critical wavelength of the threshold phenomenon is obtained by the wavelet transform and Parseval’s theorem according to simulated and experimental results. Based on this relationship, the critical frequency at which the threshold phenomenon happens due to energy transformation of transmission/reflection Rayleigh waves is adopted to determine the size of sub-wavelength surface crack. The experimental results of artificial notch depth estimation on aluminum alloy specimens consistent with theoretical analysis validates the usefulness of the critical frequency method based on a broadband Rayleigh wave generated by laser ultrasonic.

The Correlation of Dynamic Cone Penetration Blow Count of Wind Carried Sand vs. Surface Wave Velocity in West Bank of Qinghai Lake

2012 ◽  
Vol 212-213 ◽  
pp. 457-460
Author(s):  
Jian Kun Liu ◽  
Jian Hong Fang ◽  
Yong Feng Hou ◽  
Jun Hua Xiao
Keyword(s):  
Rayleigh Wave ◽  
Wave Velocity ◽  
West Bank ◽  
Qinghai Lake ◽  
Wave Method ◽  
Cone Penetration ◽  
The West ◽  
Rayleigh Wave Velocity ◽  
Surface Wave Velocity ◽  
Dynamic Cone Penetration

Based on a test of wind carried sand roadbed in the west bank of Qinghai Lake, Rayleigh wave method is introduced to measure roadbed compactness of the specific soil in China, and analysis is conducted to find correlation of Rayleigh wave velocity (VR) vs. the blow count (N10) of dynamic cone penetration, then a regression formula is presented.

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