Vibro-acoustic modulation technique for micro-crack detection in pipeline

2011 ◽  
Author(s):  
Jingpin Jiao ◽  
Lei Zheng ◽  
Guorong Song ◽  
Cunfu He ◽  
Bin Wu
Keyword(s):  
Crack Detection ◽  
Modulation Technique ◽  
Acoustic Modulation

A new vibro-acoustic modulation technique for closed crack detection based on electromagnetic loading

2020 ◽  
Vol 157 ◽  
pp. 107004 ◽  
Author(s):  
Chuang Zhang ◽  
Longlong He ◽  
Suzhen Liu ◽  
Qingxin Yang
Keyword(s):  
Crack Detection ◽  
Closed Crack ◽  
Modulation Technique ◽  
Acoustic Modulation

Influence of low-frequency parameter changes on nonlinear vibro-acoustic wave modulations used for crack detection

2017 ◽  
Vol 17 (2) ◽  
pp. 218-226 ◽  
Author(s):  
Bin Liu ◽  
Zhiwei Luo ◽  
Tie Gang
Keyword(s):  
Crack Detection ◽  
Crack Opening ◽  
Low Frequency ◽  
Intensity Variation ◽  
Sine Wave ◽  
Dynamic Strain ◽  
Low Frequency Vibration ◽  
Test Parameters ◽  
Increased Sensitivity ◽  
Acoustic Modulation

The use of vibro-acoustic modulation is an effective nonlinear and nondestructive approach to the detection and monitoring of cracks in fatigued, defective, and fractured materials. However, the vibro-acoustic modulation results strongly depend on choice of the testing parameters. To implement this technique for additional applications, the effect of variation in the test parameters must be well understood. This study investigates the influence of variation in the amplitude and frequency of pumping (low-frequency vibration) signals on the modulation. We apply two kinds of probing excitations, sine-wave and swept-signal excitations, and we measure the modulation intensity variation with changes in the relevant parameters to observe their influence on the modulations. Dynamic strain measurement of the crack area is utilized to analyze the relation between the degree of crack opening/closing and the modulation on the crack interface. The results indicate that the probing amplitude has little effect on the modulation, and furthermore, the sweep-signal excitation technique can be used to select the proper probing frequency. The results also indicate that there is a critical pumping strain value ( εc) for the crack samples. When the pumping strain reaches this critical value, the modulation reaches a maximum. However, the opening/closing area cannot increase any more even if the pumping amplitude further increases, and thus, the modulation does not change. The extent of the crack opening/closing also varies with the pumping frequency. Our results suggest that increased sensitivity to crack detection can be achieved with the use of the resonance frequency as the pumping frequency in vibro-acoustic modulation tests.

A study of the vibro-acoustic modulation technique for the detection of cracks in metals

2006 ◽  
Vol 119 (3) ◽  
pp. 1463-1475 ◽  
Author(s):  
Philippe Duffour ◽  
Marco Morbidini ◽  
Peter Cawley
Keyword(s):  
Modulation Technique ◽  
Acoustic Modulation

Crack detection technique for operating wind turbine blades using Vibro-Acoustic Modulation

2014 ◽  
Vol 13 (6) ◽  
pp. 660-670 ◽  
Author(s):  
Sungmin Kim ◽  
Douglas E Adams ◽  
Hoon Sohn ◽  
Gustavo Rodriguez-Rivera ◽  
Noah Myrent ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Crack Detection ◽  
Turbine Blades ◽  
Low Frequency ◽  
Detection Technique ◽  
New Technique ◽  
Wind Turbine Blades ◽  
Excitation Signal ◽  
Acoustic Modulation

This article presents a new technique for identifying cracks in wind turbine blades undergoing operational loads using the Vibro-Acoustic Modulation technique. Vibro-Acoustic Modulation utilizes a low-frequency pumping excitation signal in conjunction with a high-frequency probing excitation signal to create the modulation that is used to identify cracks. Wind turbines provide the ideal conditions in which Vibro-Acoustic Modulation can be utilized because wind turbines experience large low-frequency structural vibrations during operation which can serve as the low-frequency pumping excitation signal. In this article, the theory for the vibro-acoustic technique is described, and the proposed crack detection technique is demonstrated with Vibro-Acoustic Modulation experiments performed on a small Whisper 100 wind turbine in operation. The experimental results are also compared with two other conventional vibro-acoustic techniques in order to validate the new technique. Finally, a computational study is demonstrated for choosing a proper probing signal with a finite element model of the cracked blade to maximize the sensitivity of the technique for detecting cracks.

scholarly journals Analysis of Vibroacoustic Modulations for Crack Detection: A Time-Frequency Approach Based on Zhao-Atlas-Marks Distribution

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
A. Trochidis ◽  
L. Hadjileontiadis ◽  
K. Zacharias
Keyword(s):  
Acoustic Waves ◽  
Crack Detection ◽  
Damage Index ◽  
Low Frequency ◽  
Crack Size ◽  
Modulation Amplitude ◽  
Nonlinear Method ◽  
Time Frequency ◽  
Low Frequency Vibration ◽  
Acoustic Modulation

The vibro-acoustic modulation (VAM) technique is probably the most widely used nonlinear method for crack detection. The VAM method is based on the effect of modulation of high-frequency acoustic waves by a low-frequency vibration. The intensity of the modulation is related to the severity of the damage and has been used so far as a damage index. The damage index simply based on the amplitude of the first side bands in the spectral domain often leads to controversial results about the severity of the damage. In this work, the nonlinear characteristics of the vibro-modulation were systematically investigated by employing time-frequency analysis based on the Zhao-Atlas-Marks (ZAM) distribution. The results of the analysis show that the amplitude of the sideband components is modulated by the low frequency vibration and the modulation amplitude depends on the size of the crack. Based on the obtained results, a new damage index was defined in relation to the strength of the modulation. The new damage index is more sensitive and robust and correlates better with crack size compared to the index based on the amplitude of the sidebands.

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