scholarly journals Air-Coupled and Resonant Pulse-Echo Ultrasonic Technique

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2221 ◽  
Author(s):  
Tomás Gómez Álvarez-Arenas ◽  
Jorge Camacho
Keyword(s):  
Resonant Frequency ◽  
Decay Time ◽  
Dead Zone ◽  
Steel Plates ◽  
Angle Of Incidence ◽  
Ultrasonic Technique ◽  
First Wall ◽  
Resonant Modes ◽  
Quality Factor Q ◽  
Pulse Echo

An ultrasonic, resonant, pulse-echo, and air-coupled nondestructive testing (NDT) technique is presented. It is intended for components, with regular geometries where it is possible to excite resonant modes, made of materials that have a high acoustic impedance (Z) and low attenuation coefficient (α). Under these conditions, these resonances will present a very large quality factor (Q) and decay time (τ). This feature is used to avoid the dead zone, produced by the echo coming from the first wall, by receiving the resonant echo from the whole specimen over a longer period of time. This echo is analyzed in the frequency domain to determine specimen resonant frequency, which can be further used to determine either velocity or thickness. Using wideband air-coupled transducers, we tested the technique on plates (steel, aluminum, and silicone rubber) by exciting the mode of the first thickness. As expected, the higher the Z and the lower the α, the better the technique performed. Sensitivity to deviations of the angle of incidence away from normal (±2°) and the possibility to generate shear waves were also studied. Then, it was tested on steel cylindrical pipes that had different wall thicknesses and diameters. Finally, the use of this technique to generate C-Scan images of steel plates with different thicknesses was demonstrated.

In Situ Measurement of Poisson’s Ratio of Steel Plates During Thermal Processes Using Resonant Modes

2021 ◽  
Author(s):  
Clemens Grünsteidl ◽  
Christian Kerschbaummayr ◽  
Edgar Scherleitner ◽  
Bernhard Reitinger ◽  
Georg Watzl ◽  
...  
Keyword(s):  
Poisson’S Ratio ◽  
Dual Phase Steel ◽  
Steel Plates ◽  
Poisson's Ratio ◽  
Austenitic Phase ◽  
Resonant Modes ◽  
Longitudinal Sound Velocity ◽  
Contact Free

Abstract We demonstrate the determination of the Poisson’s ratio of steel plates during thermal processing based on contact free laser ultrasound measurements. Our method utilizes resonant elastic waves sustained by the plate, provides high amplitudes, and requires only a moderate detection bandwidth. For the analysis, the thickness of the samples does not need to be known. The trend of the measured Poisson’s ratio reveals a phase transformation in dual-phase steel samples. While previous approaches based on the measurement of the longitudinal sound velocity cannot distinguish between the ferritic and austenitic phase above 770°C, the shown method can. If the thickness of the samples is known, the method also provides both sound velocities of the material. The gained complementary information could be used to analyze phase composition of steel from low temperatures up to its melting point.

scholarly journals Modeling and Analysis of the Noise Performance of the Capacitive Sensing Circuit with a Differential Transformer

Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 325 ◽  
Author(s):  
Yafei Xie ◽  
Ji Fan ◽  
Chun Zhao ◽  
Shitao Yan ◽  
Chenyuan Hu ◽  
...  
Keyword(s):  
Resonant Frequency ◽  
Gravitational Wave ◽  
Mass Movement ◽  
Capacitance Measurement ◽  
Capacitive Sensing ◽  
Key Factors ◽  
Modeling And Analysis ◽  
Measurement Resolution ◽  
Laser Interferometer Space Antenna ◽  
Quality Factor Q

Capacitive sensing is a key technique to measure the test mass movement with a high resolution for space-borne gravitational wave detectors, such as Laser Interferometer Space Antenna (LISA) and TianQin. The capacitance resolution requirement of TianQin is higher than that of LISA, as the arm length of TianQin is about 15 times shorter. In this paper, the transfer function and capacitance measurement noise of the circuit are modeled and analyzed. Figure-of-merits, including the product of the inductance L and the quality factor Q of the transformer, are proposed to optimize the transformer and the capacitance measurement resolution of the circuit. The LQ product improvement and the resonant frequency augmentation are the key factors to enhance the capacitance measurement resolution. We fabricated a transformer with a high LQ product over a wide frequency band. The evaluation showed that the transformer can generate a capacitance resolution of 0.11 aF/Hz1/2 at a resonant frequency of 200 kHz, and the amplitude of the injection wave would be 0.6 V. This result supports the potential application of the proposed transformer in space-borne gravitational wave detection and demonstrates that it could relieve the stringent requirements for other parameters in the TianQin mission.

Sizing Detection of a Surface-Breaking Crack by Ultrasonic Technique

2011 ◽  
Vol 52-54 ◽  
pp. 865-868 ◽  
Author(s):  
Shiuh Chuan Her ◽  
Sheng Tung Lin
Keyword(s):  
Test Specimen ◽  
Incident Angle ◽  
Ultrasonic Technique ◽  
Non Destructive Evaluation ◽  
Different Depths ◽  
Crack Sizing ◽  
Incident Waves ◽  
Surface Breaking Crack ◽  
Pulse Echo ◽  
Non Destructive

Ultrasonic is one of the most common uses of non-destructive evaluation technique. It could detect flaws inside the structure and on the surface such as voids, holes and cracks. In this investigation, a 304 steel block with a surface-breaking crack was fabricated. A series of test specimen with different depths of surface-breaking crack ranging from 2mm to 9mm was fabricated. The depth of the surface crack was evaluated by the pulse-echo ultrasonic technique. In this work, 2.25MHz, 5MHz and 10MHz of incident waves were employed to detect the depth of the surface-breaking crack. The effect of incident angle on the measuring accuracy was investigated. Experimental results showed that the accuracy of crack sizing detection by ultrasonic technique is not only dependent on the frequency of the incident wave but also dependent on the incident angle.

Sound radiation by the bladder cicada cystosoma saundersii

1998 ◽  
Vol 201 (5) ◽  
pp. 701-715 ◽  
Author(s):  
H Bennet-Clark ◽  
D Young
Keyword(s):  
Resonant Frequency ◽  
Sound Production ◽  
Ventral Surface ◽  
Major Elements ◽  
Sound Pulse ◽  
Resonant System ◽  
Song Frequency ◽  
The Masses ◽  
Quality Factor Q ◽  
Sound Pulses

Male Cystosoma saundersii have a distended thin-walled abdomen which is driven by the paired tymbals during sound production. The insect extends the abdomen from a rest length of 32-34 mm to a length of 39-42 mm while singing. This is accomplished through specialised apodemes at the anterior ends of abdominal segments 4-7, which cause each of these intersegmental membranes to unfold by approximately 2 mm. <P> The calling song frequency is approximately 850 Hz. The song pulses have a bimodal envelope and a duration of approximately 25 ms; they are produced by the asynchronous but overlapping action of the paired tymbals. The quality factor Q of the decay of the song pulses is approximately 17. <P> The abdomen was driven experimentally by an internal sound source attached to a hole in the front of the abdomen. This allowed the sound-radiating regions to be mapped. The loudest sound-radiating areas are on both sides of tergites 3-5, approximately 10 mm from the ventral surface. A subsidiary sound-radiating region is found mid-ventrally on sternites 4-6. Sound is radiated in the same phase from all these regions. As the abdomen was extended experimentally from its resting length to its maximum length, the amplitude of the radiated sound doubled and the Q of the resonance increased from 4 to 9. This resonance and effect are similar at both tergite 4 and sternite 5. <P> Increasing the effective volume of the abdominal air sac reduced its resonant frequency. The resonant frequency was proportional to 1/(check)(total volume), suggesting that the air sac volume was the major compliant element in the resonant system. Increasing the mass of tergite 4 and sternites 4-6 also reduced the resonant frequency of the abdomen. By extrapolation, it was shown that the effective mass of tergites 3-5 was between 13 and 30 mg and that the resonant frequency was proportional to 1/(check)(total mass), suggesting that the masses of the tergal sound-radiating areas were major elements in the resonant system. <P> The tymbal ribs buckle in sequence from posterior (rib 1) to anterior, producing a series of sound pulses. The frequency of the pulse decreases with the buckling of successive ribs: rib 1 produces approximately 1050 Hz, rib 2 approximately 870 Hz and rib 3 approximately 830 Hz. The sound pulse produced as the tymbal buckles outwards is between 1.6 and 1.9 kHz. Simultaneous recordings from close to the tymbal and from tergite 4 suggest that the song pulse is initiated by the pulses produced by ribs 2 and 3 of the leading tymbal and sustained by the pulses from ribs 2 and 3 of the second tymbal. <P> An earlier model suggested that the reactive elements of the abdominal resonance were the compliance of the abdominal air sac volume and the mass of the abdomen undergoing lengthwise telescoping. The present work confirms these suggestions for the role of the air sac but ascribes the mass element to the in-out vibrations of the lateral regions of tergites 3-5 and the central part of sternites 4-6.

Detection of contact damage in ceramics by an ultrasonic method

1998 ◽  
Vol 13 (7) ◽  
pp. 1899-1904 ◽  
Author(s):  
Hyo Sok Ahn ◽  
Said Jahanmir ◽  
John A. Slotwinski ◽  
Gerald V. Blessing
Keyword(s):  
Silicon Nitride ◽  
Glass Ceramic ◽  
Ultrasonic Method ◽  
Circular Ring ◽  
Ultrasonic Technique ◽  
Surface Cracks ◽  
Compressional Waves ◽  
Different Depths ◽  
Pulse Echo ◽  
Hertzian Cone

A pulse-echo ultrasonic technique consisting of focused normal-incident compressional waves was used for the detection and evaluation of surface and subsurface damage in micaceous glass-ceramic and silicon nitride samples. The damage was produced by indentation with a tungsten carbide ball. The nature of the damage was found to be material-dependent and was classified into two types: Hertzian cone cracks in the silicon nitride, and distributed subsurface microcracks in the glass-ceramic. While the cone cracks were visible on the surface as circular ring cracks, the distributed subsurface microcracks were not associated with any visible surface cracks. Both the cone cracks and the distributed subsurface microcracks were easily detected by the ultrasonic technique. In addition, the ultrasonic beam was focused to different depths below the surface of the glass-ceramic sample to probe the subsurface region containing the microfracture damage.

Design of miniaturization resonant cavities using metamaterial

Open Physics ◽  
2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Guan Yu ◽  
Li Cao ◽  
Man Zhou
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Resonant Cavity ◽  
Transformation Optics ◽  
Resonant Cavities ◽  
Original Space ◽  
Resonant Modes ◽  
Electromagnetic Behavior ◽  
Quality Factor Q ◽  
Transformation Space

AbstractBased on the method of transformation optics, we show the miniaturization of a resonant cavity filled with metamaterials. Because the electromagnetic behavior in the transformation space is invariant in the original space, the quality factor Q and the resonant modes of a miniaturized resonant cavity filled with metamaterial are the same as for those in the original space. Theoretical analysis and numerical simulation confirms that the miniaturization of resonant cavities is effective.

An Advanced Ultrasonic Technique for Flow and Void Fraction Measurements of Two-Phase Flow

2004 ◽  
Author(s):  
J. L. H. Faccini ◽  
J. Su ◽  
G. D. Harvel ◽  
J. S. Chang
Keyword(s):  
Void Fraction ◽  
Test Section ◽  
Two Phase Flow ◽  
Flow Patterns ◽  
Ultrasonic Flowmeter ◽  
Time Averaging ◽  
Phase Flow ◽  
Ultrasonic Technique ◽  
Two Phase ◽  
Pulse Echo

In this paper, we present a hybrid type contrapropagating transmission ultrasonic technique (CPTU) for flow and time averaging ultrasonic transmission intensity void fraction measurements (TATIU) of air-water two-phase flow, which is tested in the new two-phase flow test section mounted recently onto an existing single phase flow rig at the Nuclear Engineering Institute (IEN)/CNEN, Brazil. The circular pipe test section is made of 51.2 mm stainless steel, followed by a transparent extruded acrylic pipe aimed at flow visualization. The two-phase flow rig operates in several flow regimes: bubbly, smooth stratified, wavy stratified and slug flow. The observed flow patterns are compared with the Mandhane et al.’s experimental and Lightstone et al.’s numerical flow regime map for horizontal two phase flows. These flow patterns will be identified by time averaging transmission intensity ultrasonic techniques which have been developed to meet this particular application. A contrapropagating transmission ultrasonic flowmeter is used to measure the flow rate of liquid phase. A pulse-echo TATIU ultrasonic technique used to measure the void fraction of the horizontal test section assembling at IEN is presented. Other flow parameters can be deduced by processing the signals obtained by the CPTU ultrasonic flowmeter and the pulse-echo generator-receiver (TATIU system).

Complex Envelopes for Oscillations in Slightly Nonlinear Systems

1971 ◽  
Vol 38 (4) ◽  
pp. 1012-1016
Author(s):  
W. H. Pierce
Keyword(s):  
Nonlinear System ◽  
Resonant Frequency ◽  
Broad Band ◽  
Method Of Averaging ◽  
Complex Envelope ◽  
High Q ◽  
Resonant Modes ◽  
Elliptical Motion ◽  
The Hilbert Transform ◽  
Simple Equations

A complex envelope f(t) is used to replace the traditional sine and cosine envelopes of the response of a sinusoidally forced, slightly nonlinear system, so that the response is y(t) = Re [f(t)ejw0t]. By setting Im [f(t)ejw0t] equal to the Hilbert transform of y(t), simple equations for the derivative of f(t) are easily obtained by the method of averaging. The approximations implicit in the method of averaging are shown to introduce broad-band filtering, whose effects can be eliminated by use of all harmonics. An example of an off-center rotary load shaken by a general elliptical motion shows how resonant modes of the device’s mount can be selectively energized at different frequencies, provided the modes have high Q and adequate separation of resonant frequency.

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