Ultrasonic time reversal, basic principles

2001 ◽  
Vol 110 (5) ◽  
pp. 2615-2616
Author(s):  
Didier Cassereau ◽  
Mathias Fink
Keyword(s):  
Time Reversal ◽  
Basic Principles ◽  
Ultrasonic Time

Simulation-aided time-reversal analysis for defect reconstruction in anisotropic materials

2019 ◽  
Vol 61 (11) ◽  
pp. 669-675
Author(s):  
H Mizota ◽  
Y Nagashima ◽  
Y Amano ◽  
K Nakahata
Keyword(s):  
Elastic Constants ◽  
Time Reversal ◽  
Electrical Discharge ◽  
Laser Scanning ◽  
Focal Point ◽  
Ultrasonic Method ◽  
Acoustic Resonance ◽  
Reconstruction Method ◽  
Defect Reconstruction ◽  
Ultrasonic Time

A simulation-aided defect reconstruction method using an ultrasonic time-reversal approach that uses elastic constants determined by ultrasonic field data is proposed. Scattered waves from a defect are recorded using an array probe on a polystyrene wedge and the time-reversed waves are re-emitted in a finite element simulation. The target defect in these experiments is an electrical discharge machined slit in unidirectionally solidified SUS316L stainless steel. For the time-reversal analysis, two kinds of elastic constant of SUS316L derived from an electromagnetic acoustic resonance (EMAR) method and a laser scanning ultrasonic visualisation method are used. The through-wall extent of the electrical discharge machined slit can be visually estimated from the focal point of the ultrasonic wave in the numerical model using the elastic constants determined by the laser ultrasonic method. This provides a proof of principle that the method is working.

Experimental Progress of Ultrasonic Time Reversal Mirrors

1992 ◽  
pp. 237-242 ◽  
Author(s):  
F. Wu ◽  
C. Prada ◽  
M. Fink
Keyword(s):  
Time Reversal ◽  
Ultrasonic Time

scholarly journals Damage Detection of Closed Crack in a Metallic Plate Using Nonlinear Ultrasonic Time Reversal Method

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Wang Zhang ◽  
Weiliang Wu ◽  
Xiaoyi Sun ◽  
Li Xiao ◽  
Wenzhong Qu
Keyword(s):  
Time Reversal ◽  
Damage Index ◽  
Ultrasonic Waves ◽  
Closed Crack ◽  
Time Reversibility ◽  
Imaging Algorithm ◽  
Reconstructed Signal ◽  
Ultrasonic Time ◽  
Nonlinear Ultrasonic ◽  
Nonlinear Components

Initial cracks in metallic structures incline to be closed at rest. Such incipient damage generally fails to be detected and located with traditional linear ultrasonic techniques because ultrasonic waves penetrate the contact area of the closed crack. In this paper, an imaging algorithm based on nonlinear ultrasonic time reversal method is proposed to detect closed cracks in aluminum plates. Two surface-bonded piezoelectric transducer arrays are used to generate, receive, and reemit ultrasonic wave signals. The closed crack is simulated by tightening a bolt on the aluminum plate. By applying large amplitude excitation voltage on the PZT transducers, the closed crack could be opened and closed. The transmitted waves recorded by PZT array contain nonlinear components, the signals are time reversed and emitted back, and the tone burst reconstructions are achieved. The linear reciprocity and the time reversibility break down due to the presence of the nonlinear components. The correlation coefficient between the original excitation signal and the reconstructed signal is calculated to define the damage index for individual sensing path and is used to develop an imaging algorithm to locate the closed crack on the plate. The experimental results demonstrate that incident wave signals and their reconstructed signals can be used to accurately detect and locate closed cracks.

scholarly journals P3.2 - Ultrasonic time reversal for haptic interaction

2015 ◽  
Author(s):  
S. Wöckel ◽  
H. Arndt ◽  
U. Steinmann ◽  
B. Bedürftig ◽  
J. Auge
Keyword(s):  
Time Reversal ◽  
Haptic Interaction ◽  
Ultrasonic Time
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