scholarly journals A comparison of impulse response modification techniques for time reversal with application to crack detection

2019 ◽  
Vol 145 (5) ◽  
pp. 3195-3207 ◽  
Author(s):  
Sarah M. Young ◽  
Brian E. Anderson ◽  
Matthew L. Willardson ◽  
Paige E. Simpson ◽  
Pierre-Yves Le Bas
Keyword(s):  
Impulse Response ◽  
Time Reversal ◽  
Crack Detection

scholarly journals Non-linear based time reversal acoustic applied to crack detection: Simulations and experiments

2008 ◽  
Vol 43 (3) ◽  
pp. 170-177 ◽  
Author(s):  
T. Goursolle ◽  
S. Dos Santos ◽  
O. Bou Matar ◽  
S. Callé
Keyword(s):  
Time Reversal ◽  
Crack Detection ◽  
Non Linear

Development of the Source Reconstruction System by Combining Sound Source Localization and Time Reversal Method

2016 ◽  
Vol 34 (1) ◽  
pp. 35-40
Author(s):  
S.-C. Lin ◽  
G.-P. Too ◽  
C.-W. Tu
Keyword(s):  
Impulse Response ◽  
Response Function ◽  
Source Localization ◽  
Sound Source ◽  
Time Reversal ◽  
Impulse Response Function ◽  
Source Location ◽  
Sound Source Localization ◽  
Target Sound ◽  
Reconstructed Signal

AbstractThis study explored the target sound source location at unknown situation and processed the received signal to determine the location of the target, including the reconstructed signal of source immediately. In this paper, it used triangulation sound sources localization and time reversal method (TRM) to reconstruct the source signals. The purpose is to use a sound source localization method with a simple device to quickly locate the position of the sound source. This method uses the microphone array to measure signal from the target sound source. Then, the sound source location is calculated and is indicated by Cartesian coordinates. The sound source location is then used to evaluate free field impulse response function which can replace the impulse response function used in time-reversal method. This process reduces the computation time greatly which makes possible for a real time source localization and source signal separation.

Numerical Investigation of Nonlinear Lamb Wave Time Reversing for Fatigue Crack Detection

2019 ◽  
Author(s):  
Junzhen Wang ◽  
Yanfeng Shen
Keyword(s):  
Finite Element ◽  
Fatigue Crack ◽  
Time Reversal ◽  
Lamb Wave ◽  
Crack Detection ◽  
Guided Waves ◽  
Fatigue Cracks ◽  
Contact Dynamics ◽  
Virtual Time ◽  
Fatigue Crack Detection

Abstract This paper presents a numerical study on nonlinear Lamb wave time reversing for fatigue crack detection. An analytical framework is initially presented, modeling Lamb wave generation, propagation, wave crack linear and nonlinear interaction, and reception. Subsequently, a 3D transient dynamic coupled-field finite element model is constructed to simulate the pitch-catch procedure in an aluminum plate using the commercial finite element software (ANSYS). The excitation frequency is carefully selected, where only single Lamb wave mode will be generated by the Piezoelectric Wafer Active Sensor (PWAS). The fatigue cracks are modelled nucleating from both sides of a rivet hole. In addition, contact dynamics are considered to capture the nonlinear interactions between guided waves and the fatigue cracks, which would induce Contact Acoustic Nonlinearity (CAN) into the guided waves. Then the conventional and virtual time reversal methods are realized by finite element simulation. Advanced signal processing techniques are used to extract the distinctive nonlinear features. Via the Fast Fourier Transform (FFT) and time-frequency spectral analysis, nonlinear superharmonic components are observed. The reconstructed signals attained from the conventional and virtual time reversal methods are compared and analyzed. Finally, various Damage Indices (DIs), based on the difference between the reconstructed signal and the excitation waveform as well as the amplitude ratio between the superharmonic and the fundamental frequency components are adopted to evaluate the fatigue crack severity. The DIs could provide quantitative diagnostic information for fatigue crack detection. This paper finishes with summary, concluding remarks, and suggestions for future work.

The time reversal effect of the impulse response of crust

2001 ◽  
Vol 14 (4) ◽  
pp. 394-403 ◽  
Author(s):  
Wen-heng Zheng ◽  
Cheng Wang ◽  
Xiang-peng Chen
Keyword(s):  
Impulse Response ◽  
Time Reversal ◽  
Reversal Effect

ANALYSIS OF ALTERNATIVE METHODS FOR IMPULSE RESPONSE FUNCTIONS BASED ON SIGNAL-TO-NOISE RATIO ENHANCEMENT AND COMPLETENESS OF SOURCE SIGNAL RECONSTRUCTION USING PASSIVE TIME REVERSAL

2013 ◽  
Vol 21 (03) ◽  
pp. 1350008 ◽  
Author(s):  
YU-HAO HSIEH ◽  
GEE-PINN TOO
Keyword(s):  
Impulse Response ◽  
Response Function ◽  
Time Reversal ◽  
Signal To Noise Ratio ◽  
Impulse Response Function ◽  
Computation Time ◽  
Alternative Methods ◽  
Impulse Response Functions ◽  
Response Functions ◽  
Source Signal

Noise reduction and signal separation are important functions of acoustic signal processing. This study presents a detailed analysis for designing an acoustic signal processing procedure based on the time-reversal method. For some applications, setting transducers to retransmit at source locations is impracticable. Modeling a wave propagation path between two points using impulse response function is one way to overcome this limitation. This paper introduces alternative methods to calculate impulse response function, including an adaptive digital filter, deconvolution with singular value decomposition and Tikhonov regularization, and correlation. A discussion is also provided on the applicable frequency range and anti-noise ability of the impulse response functions obtained by all three techniques through simulation, and subsequently applies them to the designed time reversal process to enhance the signal-to-noise ratio (SNR) and restore source signals through experimentation. The conclusions of this study are given based on the level of accuracy using the SNR and correlation coefficient as indicators, and the computation time required by alternative methods is also an important factor to be discussed for real-time system design. Results prove that the proposed passive time reversal process is capable of enhancing the SNR and restoring the source signal. The alternative methods of calculating the impulse response function offer various advantages, and should be selected according to the application. If the time-cost is the first consideration and there is no dominant noise source, then correlation is the best choice for calculating impulse response function. If completeness of the reconstructed signal is the key point, the optimal deconvolution process is appropriate. If noise reduction is the highest priority in extracting a useful signal from noisy environments while ensuring acceptable restoration capability and computation time, an adaptive digital filter is suitable.

Determination of the minimum length impulse response for time reversal focalization in acoustic cavities

2012 ◽  
Author(s):  
Nicolás Pérez ◽  
Marcelo Y. Matuda ◽  
Carlos Negreira ◽  
Julio C. Adamowski
Keyword(s):  
Impulse Response ◽  
Time Reversal ◽  
Minimum Length ◽  
Acoustic Cavities
Sign in / Sign up

Export Citation Format

Share Document