US20010045130A1 - Flaw detection system using acoustic doppler effect - Google Patents
Flaw detection system using acoustic doppler effect Download PDFInfo
- Publication number
- US20010045130A1 US20010045130A1 US09/770,323 US77032301A US2001045130A1 US 20010045130 A1 US20010045130 A1 US 20010045130A1 US 77032301 A US77032301 A US 77032301A US 2001045130 A1 US2001045130 A1 US 2001045130A1
- Authority
- US
- United States
- Prior art keywords
- acoustic
- medium
- detection system
- doppler effect
- flaw detection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61K—AUXILIARY EQUIPMENT SPECIALLY ADAPTED FOR RAILWAYS, NOT OTHERWISE PROVIDED FOR
- B61K9/00—Railway vehicle profile gauges; Detecting or indicating overheating of components; Apparatus on locomotives or cars to indicate bad track sections; General design of track recording vehicles
- B61K9/08—Measuring installations for surveying permanent way
- B61K9/10—Measuring installations for surveying permanent way for detecting cracks in rails or welds thereof
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/22—Details, e.g. general constructional or apparatus details
- G01N29/24—Probes
- G01N29/2412—Probes using the magnetostrictive properties of the material to be examined, e.g. electromagnetic acoustic transducers [EMAT]
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/22—Details, e.g. general constructional or apparatus details
- G01N29/24—Probes
- G01N29/2418—Probes using optoacoustic interaction with the material, e.g. laser radiation, photoacoustics
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/22—Details, e.g. general constructional or apparatus details
- G01N29/26—Arrangements for orientation or scanning by relative movement of the head and the sensor
- G01N29/265—Arrangements for orientation or scanning by relative movement of the head and the sensor by moving the sensor relative to a stationary material
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/36—Detecting the response signal, e.g. electronic circuits specially adapted therefor
- G01N29/40—Detecting the response signal, e.g. electronic circuits specially adapted therefor by amplitude filtering, e.g. by applying a threshold or by gain control
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/36—Detecting the response signal, e.g. electronic circuits specially adapted therefor
- G01N29/42—Detecting the response signal, e.g. electronic circuits specially adapted therefor by frequency filtering or by tuning to resonant frequency
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/01—Indexing codes associated with the measuring variable
- G01N2291/017—Doppler techniques
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/10—Number of transducers
- G01N2291/101—Number of transducers one transducer
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/10—Number of transducers
- G01N2291/102—Number of transducers one emitter, one receiver
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/26—Scanned objects
- G01N2291/262—Linear objects
- G01N2291/2623—Rails; Railroads
Definitions
- This invention relates to a flaw detection system using acoustic Doppler effect for detecting flaws in a medium to be inspected wherein there is relative motion between the system and medium.
- Typical defects often found in railroad tracks include transverse and longitudinal defects in the rail head, web defects, base defects, surface defects as well as other miscellaneous damage such as head wear, corrosion, crushed head, burned rail, bolt hole cracks, head and web separation.
- Nondestructive evaluation of rail tracks may be approached by continuous monitoring or detailed inspection.
- continuous monitoring results in global evaluation of the rail whereas detailed inspection focuses on a particular area to locate and/or characterize a defect in detail.
- the invention results from the realization that a truly elegant yet extremely reliable continuous and high speed detection system for detecting a flaw in a medium such as a conveyor belt, cable, rope, railroad track or road can be effected by sensing a Doppler shift in a carrier signal caused by a flaw.
- This invention features a flaw detection system using acoustic Doppler effect for detecting flaws in a medium wherein there is relative motion between the medium and system.
- transducer means spaced from the medium to be inspected, for introducing to and sensing from the medium an acoustic signal that propagates in said medium at a predetermined frequency.
- means responsive to the sensed propagating acoustic signal, for detecting in the sensed acoustic signal the Doppler shifted frequency representative of a flaw in the medium.
- the transducer means may include a separate transmitter and receiver.
- the transducer may be an ultrasonic transducer and the acoustic signal an ultrasonic signal.
- the transducer may transmit an acoustic signal from propagation in the medium or the transducer may transmit optical energy for inducing the acoustic signal in the medium.
- the transducer may include a laser for transmitting that optical energy.
- the transducer may include an acoustic receiver.
- the transducer may include an electromagnetic acoustic transmitter and receiver for inducing an acoustic signal into the medium and sensing the Doppler shifted acoustic signal.
- the means for detecting may include a spectrum analyzer, or a bandpass filter and a peak detector, or an A to D converter and a digital filter for the purpose of distinguishing the Doppler effect frequency.
- a thresholding circuit identified with any one of the options for identifying a preselected label as a flaw.
- the medium to be inspected may be a railroad rail.
- the transducer may transmit to the surface of the medium and receive from the surface of the medium an acoustic signal and the flaws detected may be surface flaws. Or the transmitter may induce an acoustic signal internally in the medium and the flaws detected may be internal flaws.
- the transducer means may include a laser vibrometer interferometer for sensing the acoustic signal propagating in the medium.
- the invention also features a flaw detection system using acoustic Doppler effect for detecting surface flaws when there is relative motion between the medium and system.
- Means responsive to the reflected acoustic signal distinguish the Doppler shifted frequency in the reflected acoustic signal from the predetermined frequency of the transmitted acoustic signal representative of a surface flaw in the medium.
- the invention also features a flaw detection system using acoustic Doppler effect for detecting flaws in a medium wherein there is relative motion between the medium and system.
- transducer means spaced from the medium to be inspected for inducing an acoustic signal to propagate the medium at a predetermined frequency and sensing the propagated acoustic signal in the medium.
- the transducer means may include an electromagnetic acoustic transducer for inducing and sensing the acoustic signal.
- the transducer means may include a transmitter and a receiver and the transmitter may include a laser for locally heating the medium to generate acoustic signals.
- FIG. 1 is a schematic block diagram of a flaw detection system using acoustic Doppler effect detection system according to this invention adapted to inspect for defects in a railroad rail;
- FIG. 2 is an enlarged detailed view of the acoustic transducer of FIG. 1 implemented with separate receiver and transmitter in the ultrasonic range;
- FIG. 3 illustrates the output signal from the acoustic transducer
- FIG. 4A illustrates the output carrier signal reflected from the unflawed surface
- FIG. 4B illustrates the Doppler shifted return signal reflected from a surface flaw
- FIG. 4C is the magnitude spectrum of the signal reflected from the unflawed surface
- FIG. 4D is the magnitude spectrum of the reflection from the flaw
- FIG. 5 is a more detailed block diagram of one implementation of the Doppler detection circuit of FIG. 1;
- FIG. 6 is a more detailed block diagram of another implementation of the Doppler detection circuit of FIG. 1;
- FIG. 7 is a more detailed block diagram of another implementation of the Doppler detection circuit of FIG. 1;
- FIG. 9A illustrates the magnitude spectrum of the Doppler window
- FIG. 9B illustrates the inverse Fourier transform of the magnitude spectrum of FIG. 9A
- FIG. 9C is the result of convoluting the inverse Fourier transform of FIG. 9B with the input signal of FIG. 3;
- FIGS. 10A, B and C are schematic diagrams showing the acoustic transducer implemented with an electromagnetic acoustic transducer using separate spaced transmitter and receiver, separate adjacent transmitter and receiver, and a single combined transmitter/receiver unit, respectively;
- FIG. 11 is a schematic view of another form of transducer using a laser acoustic transmitter.
- An advantageous feature of the high-speed flaw detection system using acoustic Doppler effect is that the transducer need not, and in fact preferably is not, in contact with the rail or other medium to be inspected. Instead, the transducer remotely senses the discontinuities through the air.
- EMAT electromagnetic acoustic transducers
- G.A. Alers Railroad Rail Flaw Detection System Based on Electromagnetic Acoustic Transducers, U.S. Department of Transportation Report DOT/FRA/ORD-88-09 (1988)
- LBU laser-based acoustic or ultrasound
- Air-coupled piezoelectric transducers have shown interesting results in some materials (A. Safaeinili, O. I. Lobkis, nd D. E. Chimenti, “Air-coupled Ultrasonic Characterization of Composite Plates”, Materials Evaluation, Vol. 53, 1186-1190 (October 1995)). Air-coupled transducers are attractive because they allow ultrasound to propagate through gaseous media without requiring mechanical contact between the transducer and the medium to be inspected.
- the acoustic impedance mismatch between the steel and air is used to great advantage since it reflects most of the energy from the steel surface back to the transducer.
- a typical car speed for monitoring the rail may reach above sixty miles per hour and in fact, increased car speed leads to more pronounced Doppler effects and better overall efficiency.
- FIG. 1 There is shown in FIG. 1 a flaw detection system using acoustic Doppler effect system 10 according to this invention mounted on a railroad car 12 , indicated generally in phantom, which moves in either direction as indicated by arrow 14 along railroad rail 16 , which contains a flaw 18 on its surface.
- System 10 includes a non-contact acoustic transducer 20 which beams out an acoustic signal 22 , referred to as a carrier signal, which reflects back from rail 16 as the returned or reflected signal 24 .
- a carrier signal which reflects back from rail 16 as the returned or reflected signal 24 .
- the carrier signal comes back with its frequency unchanged, but when acoustic signal 22 strikes flaw 18 the return signal 24 will contain Doppler shifted frequency.
- the Doppler shift may be an increase or a decrease in frequency.
- the return acoustic signal 24 is sensed and transduced to an electric signal and submitted to Doppler detection circuit 26 which extracts the Doppler frequency and then submits it to a threshold or comparator circuit 28 . If the Doppler frequency is above a preselected reference level a defect alarm output is provided by threshold circuit 28 .
- f S is the frequency of the input signal
- ⁇ f is the difference between the input frequency and the Doppler shifted frequency
- v S is the relative speed between the system and the medium to be inspected, in this case for example it may be the railroad car carrying the system traveling at for example sixty miles an hour
- c is the wave speed in the medium, air in this case
- ⁇ is the angle between the direction of motion and the direction to the receiving transducer from the notch.
- Acoustic transducer 20 may be a single transducer which acts as both transmitter and receiver, or it may be two separate units, one a transmitter, the other a receiver.
- transducer 20 a includes such discrete devices where a transmitter 30 transmits an ultrasonic output beam 22 a and ultrasonic receiver 32 receives the reflected ultrasonic signal 24 a.
- the output 40 , FIG. 3, of transducer 20 shows a general smooth amplitude profile over time in the areas 42 but shows distinctive characteristics 44 where a defect such as defect 18 has been seen.
- the output acoustic signal 22 b, FIG. 4A is in the range of 100 kHz.
- the magnitude spectrum 22 bb, FIG. 4C, of output signal 22 b shows a marked rise at 100 kHz while the magnitude spectrum 24 bb, FIG. 4D for the return signal 24 b is accompanied by a very distinct peak 50 at about 115 kHz which is the Doppler shifted frequency resulting from the Doppler effect caused by the flaw 18 .
- Doppler detection circuit 26 may be implemented in any number of ways.
- detection circuit 26 a, FIG. 5 may include an analog bandpass filter 60 which provides a bandpass window centered on 115 kHz where the Doppler shift is expected at a relative speed of 60 miles an hour between the medium and system. The output from filter 60 is then selected by gated peak detector 62 so that any signals appearing in that band above a certain level will be accepted as a flaw detection.
- Doppler detection circuit 26 b, FIG. 6, may include a spectrum analyzer 64 which directly provides the Doppler shifted frequency output.
- Doppler detection circuit 26 may include an analog to digital converter 66 which converts the analog signal to a digital signal and then submits it to a programmable digital signal processor 68 .
- the programmable digital signal processor may be programmed in a number of different ways. For example, it may be programmed to operate as a Short-Time Fourier transform. Beginning with the signal as shown in FIG.
- the acoustic signals are continuous wave signals, this is not a necessary limitation of the invention as pulse or spike pulse signals can also be used.
- an electromagnetic acoustic transducer or EMAT may be used for monitoring internal flaws 18 b, c, d, FIGS. 10A, 10B and 10 C.
- Such a transducer 20 b, FIG. 10A may include an electromagnetic transmitter 30 b and receiver 32 b for monitoring internal flaws such as flaw 18 b. While transmitter and receiver 30 b and 32 b are spaced apart, FIG. 10A, this is not a necessary limitation for as shown in FIG.
- EMAT transmitter 30 c and receiver 32 c may be adjacent to one another and it is not necessary that the receiver and transmitter be separate, for as shown in FIG. 10C an EMAT transducer 20 d which both transmits and receives can be used.
- the EMAT transmitter 30 b establishes a varying magnetic field 31 b which induces the acoustic signal 22 b in rail 16 .
- EMAT receiver 32 b through its magnetic field 33 b senses the acoustic return signal 24 b.
- the transmitter may be a laser 30 e that either provides its energy directly over beam 22 e or through optical fiber cable 90 delivers its energy to rail 16 where it induces an acoustic wave that propagates in rail 16 .
- the laser should be a powerful one such as a Q-switched Nd:YAG laser.
- the receiver 32 e may be an EMAT transducer or an acoustic transducer as already disclosed or may be an interferometer vibrometer device using a Fabry-Perot technique, for example.
Abstract
A flaw detection system using acoustic Doppler effect for detecting flaws in a medium wherein there is relative motion between the medium and system includes a transducer, spaced from the medium to be inspected, for introducing to and sensing from the medium an acoustic signal that propagates in the medium at a predetermined frequency; and a detector, responsive to the sensed propagating acoustic signal, for detecting in the sensed acoustic signal the Doppler shifted frequency representative of a flaw in the medium.
Description
- This invention relates to a flaw detection system using acoustic Doppler effect for detecting flaws in a medium to be inspected wherein there is relative motion between the system and medium.
- Railroads provide both efficiency and economy in passenger and freight transportation. Like other transportation modes, however, they are prone to various problems. Statistics show that over the course of this century, the average carload and trainload tonnage has increased significantly. There is also an increasing concentration of traffic on fewer main line tracks. The average length of haul has also risen. Unfortunately, these trends have not been offset with a proportional increase in the amount of new rail laid. Consequently, the stress on rails and fatigue related failures may continue to increase. With the new demands, it is important to assess the rail integrity by detecting rail defects nondestructively and speedily.
- Typical defects often found in railroad tracks include transverse and longitudinal defects in the rail head, web defects, base defects, surface defects as well as other miscellaneous damage such as head wear, corrosion, crushed head, burned rail, bolt hole cracks, head and web separation.
- Nondestructive evaluation of rail tracks may be approached by continuous monitoring or detailed inspection. In the context of rail assessment, continuous monitoring results in global evaluation of the rail whereas detailed inspection focuses on a particular area to locate and/or characterize a defect in detail.
- In continuous monitoring, some techniques for inspection of rail flaws at an intermediate speed are currently available, but the technology lacks efficient monitoring techniques at a high speed comparable to the speed of a passenger car. One of the limitations on speed is the need for the transducer to be in contact with the rail. Furthermore, existing detailed inspection techniques have limited capabilities, primarily due to poor sensor performance and the requirement of contact with the rail surface.
- Currently, surface defects are detected by means of a device called a track circuit. This device uses the track as part of an electric circuit and uses the resistivity of the rail as an indication of surface discontinuities. Another approach is the use of ultrasonic probes in contact with the track surface by a rolling wheel. These techniques require contact with the sensor and the rail. Therefore, they are not quite suitable for high-speed monitoring.
- Improved inspection systems are needed in many other applications, for example, in which there is relative motion between the system and medium to be inspected such as conveyors, cables, ropes and roadbeds. Presently inspection techniques tend to be slow and not so reliable because they typically use a change in the amplitude of the probe signal to identify a defect or flaw. Amplitude data is not easily repeatable or reliable.
- It is therefore an object of this invention to provide a flaw detection system using acoustic Doppler effect for detecting flaws in a medium to be inspected.
- It is a further object of this invention to provide such a flaw detection system using acoustic Doppler effect which is faster and more reliable.
- It is a further object of this invention to provide such a flaw detection system using acoustic Doppler effect which is adapted for detecting flaws in a variety of moving and stationery mediums such as conveyors, cables, ropes, railroad tracks and roads.
- It is a further object of this invention to provide such a flaw detection system using acoustic Doppler effect which utilizes a change in frequency not amplitude to identify a flaw.
- It is a further object of this invention to provide such a flaw detection system using acoustic Doppler effect which is capable of extremely high speed operation and improves its resolution with speed.
- It is a further object of this invention to provide such a flaw detection system using acoustic Doppler effect which operates in a remote or non-contact mode spaced from the medium to be inspected.
- It is a further object of this invention to provide such a flaw detection system using acoustic Doppler effect which can be used to detect surface or internal flaws.
- It is a further object of this invention to provide such a flaw detection system using acoustic Doppler effect in which stronger signals can be obtained in surface flaw inspection due to air coupling of acoustic signals.
- It is a further object of this invention to provide such a flaw detection system using acoustic Doppler effect which enables continuous non-stop monitoring.
- The invention results from the realization that a truly elegant yet extremely reliable continuous and high speed detection system for detecting a flaw in a medium such as a conveyor belt, cable, rope, railroad track or road can be effected by sensing a Doppler shift in a carrier signal caused by a flaw.
- This invention features a flaw detection system using acoustic Doppler effect for detecting flaws in a medium wherein there is relative motion between the medium and system. There are transducer means, spaced from the medium to be inspected, for introducing to and sensing from the medium an acoustic signal that propagates in said medium at a predetermined frequency. There are also means, responsive to the sensed propagating acoustic signal, for detecting in the sensed acoustic signal the Doppler shifted frequency representative of a flaw in the medium.
- In a preferred embodiment the transducer means may include a separate transmitter and receiver. The transducer may be an ultrasonic transducer and the acoustic signal an ultrasonic signal. The transducer may transmit an acoustic signal from propagation in the medium or the transducer may transmit optical energy for inducing the acoustic signal in the medium. The transducer may include a laser for transmitting that optical energy. The transducer may include an acoustic receiver. The transducer may include an electromagnetic acoustic transmitter and receiver for inducing an acoustic signal into the medium and sensing the Doppler shifted acoustic signal. The means for detecting may include a spectrum analyzer, or a bandpass filter and a peak detector, or an A to D converter and a digital filter for the purpose of distinguishing the Doppler effect frequency. In addition there may be a thresholding circuit identified with any one of the options for identifying a preselected label as a flaw. The medium to be inspected may be a railroad rail. The transducer may transmit to the surface of the medium and receive from the surface of the medium an acoustic signal and the flaws detected may be surface flaws. Or the transmitter may induce an acoustic signal internally in the medium and the flaws detected may be internal flaws. The transducer means may include a laser vibrometer interferometer for sensing the acoustic signal propagating in the medium.
- The invention also features a flaw detection system using acoustic Doppler effect for detecting surface flaws when there is relative motion between the medium and system. There is an acoustic transducer means spaced from the medium to be inspected for transmitting an acoustic signal to and receiving the reflected acoustic signal at a predetermined frequency from the surface of the medium to be inspected. Means responsive to the reflected acoustic signal distinguish the Doppler shifted frequency in the reflected acoustic signal from the predetermined frequency of the transmitted acoustic signal representative of a surface flaw in the medium.
- The invention also features a flaw detection system using acoustic Doppler effect for detecting flaws in a medium wherein there is relative motion between the medium and system. There are transducer means spaced from the medium to be inspected for inducing an acoustic signal to propagate the medium at a predetermined frequency and sensing the propagated acoustic signal in the medium. Means, responsive to the sensed propagating acoustic signal, distinguish the Doppler shifted frequency representative of a flaw in the medium.
- In a preferred embodiment the transducer means may include an electromagnetic acoustic transducer for inducing and sensing the acoustic signal. The transducer means may include a transmitter and a receiver and the transmitter may include a laser for locally heating the medium to generate acoustic signals.
- Other objects, features and advantages will occur to those skilled in the art from the following description of a preferred embodiment and the accompanying drawings, in which:
- FIG. 1 is a schematic block diagram of a flaw detection system using acoustic Doppler effect detection system according to this invention adapted to inspect for defects in a railroad rail;
- FIG. 2 is an enlarged detailed view of the acoustic transducer of FIG. 1 implemented with separate receiver and transmitter in the ultrasonic range;
- FIG. 3 illustrates the output signal from the acoustic transducer;
- FIG. 4A illustrates the output carrier signal reflected from the unflawed surface;
- FIG. 4B illustrates the Doppler shifted return signal reflected from a surface flaw;
- FIG. 4C is the magnitude spectrum of the signal reflected from the unflawed surface;
- FIG. 4D is the magnitude spectrum of the reflection from the flaw;
- FIG. 5 is a more detailed block diagram of one implementation of the Doppler detection circuit of FIG. 1;
- FIG. 6 is a more detailed block diagram of another implementation of the Doppler detection circuit of FIG. 1;
- FIG. 7 is a more detailed block diagram of another implementation of the Doppler detection circuit of FIG. 1;
- FIG. 8 illustrates the peak magnitude of a Short Time Fourier Transform implementation of the programmable digital signal processor of FIG. 7;
- FIG. 9A illustrates the magnitude spectrum of the Doppler window;
- FIG. 9B illustrates the inverse Fourier transform of the magnitude spectrum of FIG. 9A;
- FIG. 9C is the result of convoluting the inverse Fourier transform of FIG. 9B with the input signal of FIG. 3;
- FIGS. 10A, B and C are schematic diagrams showing the acoustic transducer implemented with an electromagnetic acoustic transducer using separate spaced transmitter and receiver, separate adjacent transmitter and receiver, and a single combined transmitter/receiver unit, respectively; and
- FIG. 11 is a schematic view of another form of transducer using a laser acoustic transmitter.
- An advantageous feature of the high-speed flaw detection system using acoustic Doppler effect according to this invention is that the transducer need not, and in fact preferably is not, in contact with the rail or other medium to be inspected. Instead, the transducer remotely senses the discontinuities through the air. There are several devices that operate in a non-contact mode including electromagnetic acoustic transducers (EMAT) (G.A. Alers,Railroad Rail Flaw Detection System Based on Electromagnetic Acoustic Transducers, U.S. Department of Transportation Report DOT/FRA/ORD-88-09 (1988) and laser-based acoustic or ultrasound (LBU) (C. B. Scruby and L. E. Drain, Laser-Ultrasonics: Techniques and Applications, Adam Hilger, Briston, UK (1990)). More recently, air-coupled piezoelectric transducers have shown interesting results in some materials (A. Safaeinili, O. I. Lobkis, nd D. E. Chimenti, “Air-coupled Ultrasonic Characterization of Composite Plates”, Materials Evaluation, Vol. 53, 1186-1190 (October 1995)). Air-coupled transducers are attractive because they allow ultrasound to propagate through gaseous media without requiring mechanical contact between the transducer and the medium to be inspected. When used for inspecting railroad tracks the acoustic impedance mismatch between the steel and air is used to great advantage since it reflects most of the energy from the steel surface back to the transducer. When the invention is employed in railroad rail monitoring, a typical car speed for monitoring the rail may reach above sixty miles per hour and in fact, increased car speed leads to more pronounced Doppler effects and better overall efficiency.
- There is shown in FIG. 1 a flaw detection system using acoustic
Doppler effect system 10 according to this invention mounted on arailroad car 12, indicated generally in phantom, which moves in either direction as indicated byarrow 14 alongrailroad rail 16, which contains aflaw 18 on its surface.System 10 includes a non-contactacoustic transducer 20 which beams out an acoustic signal 22, referred to as a carrier signal, which reflects back fromrail 16 as the returned or reflectedsignal 24. When signal 22 strikes the smooth portion ofrail 16 the carrier signal comes back with its frequency unchanged, but when acoustic signal 22strikes flaw 18 thereturn signal 24 will contain Doppler shifted frequency. Depending upon the position of the movingvehicle 12 and/or the direction of the acoustic signal output 22, the Doppler shift may be an increase or a decrease in frequency. The returnacoustic signal 24 is sensed and transduced to an electric signal and submitted toDoppler detection circuit 26 which extracts the Doppler frequency and then submits it to a threshold orcomparator circuit 28. If the Doppler frequency is above a preselected reference level a defect alarm output is provided bythreshold circuit 28. -
- where fS is the frequency of the input signal, Δf is the difference between the input frequency and the Doppler shifted frequency, vS is the relative speed between the system and the medium to be inspected, in this case for example it may be the railroad car carrying the system traveling at for example sixty miles an hour, c is the wave speed in the medium, air in this case, and ψ is the angle between the direction of motion and the direction to the receiving transducer from the notch.
-
Acoustic transducer 20 may be a single transducer which acts as both transmitter and receiver, or it may be two separate units, one a transmitter, the other a receiver. In FIG. 2transducer 20 a includes such discrete devices where atransmitter 30 transmits anultrasonic output beam 22 a andultrasonic receiver 32 receives the reflectedultrasonic signal 24 a. - The
output 40, FIG. 3, oftransducer 20 shows a general smooth amplitude profile over time in theareas 42 but showsdistinctive characteristics 44 where a defect such asdefect 18 has been seen. Typically the outputacoustic signal 22 b, FIG. 4A, is in the range of 100 kHz. Upon hitting a defect or flaw the return wave appears as at 24 b in FIG. 4B. The magnitude spectrum 22 bb, FIG. 4C, ofoutput signal 22 b shows a marked rise at 100 kHz while themagnitude spectrum 24 bb, FIG. 4D for thereturn signal 24 b is accompanied by a verydistinct peak 50 at about 115 kHz which is the Doppler shifted frequency resulting from the Doppler effect caused by theflaw 18. -
Doppler detection circuit 26 may be implemented in any number of ways. For example,detection circuit 26 a, FIG. 5, may include ananalog bandpass filter 60 which provides a bandpass window centered on 115 kHz where the Doppler shift is expected at a relative speed of 60 miles an hour between the medium and system. The output fromfilter 60 is then selected bygated peak detector 62 so that any signals appearing in that band above a certain level will be accepted as a flaw detection. Alternatively,Doppler detection circuit 26 b, FIG. 6, may include aspectrum analyzer 64 which directly provides the Doppler shifted frequency output. - In another
implementation 26 c, FIG. 7,Doppler detection circuit 26 may include an analog todigital converter 66 which converts the analog signal to a digital signal and then submits it to a programmabledigital signal processor 68. The programmable digital signal processor may be programmed in a number of different ways. For example, it may be programmed to operate as a Short-Time Fourier transform. Beginning with the signal as shown in FIG. 3, the Short-Time Fourier Transform - results in discrete and
prominent features 44 a, FIG. 8, corresponding to each of the flaws ordefects 44 in FIG. 3. - Alternatively, the programmable
digital signal processor 68 may be programmed to produce a bandpass 70, FIG. 9A, in the range of 105 to 115 kHz then obtain theinverse transform 72, FIG. 9B, ofresponse 70 and convolve it with the return or reflected signal as shown in FIG. 3 in accordance with the input signal designated x(n) and the filter coefficient h(n) in the discrete-time domain directly as shown in the following expression: - wherein y is the filtered output signal, N is the number of points, h is the filter coefficient, k and n are index variables, and x is the input signal. The result of that convolution is shown in FIG. 9C wherein each of the flaws or
defects 44, FIG. 3, creates a discrete and veryprominent feature 44 b. - Although as disclosed herein the acoustic signals are continuous wave signals, this is not a necessary limitation of the invention as pulse or spike pulse signals can also be used. For monitoring
internal flaws 18 b, c, d, FIGS. 10A, 10B and 10C, an electromagnetic acoustic transducer or EMAT may be used. Such atransducer 20 b, FIG. 10A, may include anelectromagnetic transmitter 30 b andreceiver 32 b for monitoring internal flaws such asflaw 18 b. While transmitter andreceiver EMAT transmitter 30 c andreceiver 32 c may be adjacent to one another and it is not necessary that the receiver and transmitter be separate, for as shown in FIG. 10C anEMAT transducer 20 d which both transmits and receives can be used. As is well known, theEMAT transmitter 30 b establishes a varyingmagnetic field 31 b which induces theacoustic signal 22 b inrail 16.EMAT receiver 32 b through itsmagnetic field 33 b senses theacoustic return signal 24 b. - Yet another
transducer 20 e, FIG. 11, is shown in which the transmitter may be alaser 30 e that either provides its energy directly overbeam 22 e or throughoptical fiber cable 90 delivers its energy to rail 16 where it induces an acoustic wave that propagates inrail 16. The laser should be a powerful one such as a Q-switched Nd:YAG laser. Thereceiver 32 e may be an EMAT transducer or an acoustic transducer as already disclosed or may be an interferometer vibrometer device using a Fabry-Perot technique, for example. - Although specific features of this invention are shown in some drawings and not others, this is for convenience only as each feature may be combined with any or all of the other features in accordance with the invention.
- Other embodiments will occur to those skilled in the art and are within the following claims:
Claims (21)
1. A flaw detection system using acoustic Doppler effect for detecting flaws in a medium wherein there is relative motion between the medium and system comprising:
transducer means, spaced from the medium to be inspected, for introducing to and sensing from the medium an acoustic signal that propagates in said medium at a predetermined frequency; and
means, responsive to the sensed propagating acoustic signal, for detecting in the sensed acoustic signal the Doppler shifted frequency representative of a flaw in the medium.
2. The flaw detection system using acoustic Doppler effect of in which said transducer means includes a separate transmitter and receiver.
claim 1
3. The flaw detection system using acoustic Doppler effect of in which said transducer means is an ultrasonic transducer and said acoustic signal is an ultrasonic signal.
claim 1
4. The flaw detection system using acoustic Doppler effect of in which said transducer transmits an acoustic signal for propagation in said medium.
claim 1
5. The flaw detection system using acoustic Doppler effect of in which said transducer transmits optical energy for inducing the acoustic signal in said medium.
claim 1
6. The flaw detection system using acoustic Doppler effect of in which said transducer includes a laser for transmitting said optical energy.
claim 5
7. The flaw detection system using acoustic Doppler effect of in which said transducer includes an acoustic receiver.
claim 1
8. The flaw detection system using acoustic Doppler effect of in which said transducer includes an electromagnetic acoustic transmitter and receiver for inducing an acoustic signal into said medium and sensing the Doppler shifted acoustic signal.
claim 1
9. The flaw detection system using acoustic Doppler effect of in which said means for detecting includes a spectrum analyzer for distinguishing the Doppler effect frequency.
claim 1
10. The flaw detection system using acoustic Doppler effect of in which said means for detecting includes a thresholding circuit for identifying a preselected level as a flaw.
claim 9
11. The flaw detection system using acoustic Doppler effect of in which said means for detecting includes a bandpass filter and a peak detector for distinguishing the Doppler effect frequency.
claim 1
12. The flaw detection system using acoustic Doppler effect of in which said means for detecting includes a thresholding circuit for identifying a preselected level as a flaw.
claim 11
13. The flaw detection system using acoustic Doppler effect of in which said means for detecting includes an A/D converter and a digital filter for distinguishing the Doppler effect frequency, and a thresholding circuit for identifying a preselected level as a flaw.
claim 1
14. The flaw detection system using acoustic Doppler effect of in which said medium is a railroad rail.
claim 1
15. The flaw detection system using acoustic Doppler effect of in which said transducer means transmits to the surface of the medium and receives from the surface of the medium an acoustic signal and the flaws detected are surface flaws.
claim 1
16. The flaw detection system using acoustic Doppler effect of in which said transducer means induces an acoustic signal internally in the medium and the flaws detected are internal flaws.
claim 1
17. The flaw detection system using acoustic Doppler effect of in which said transducer means includes a laser vibrometer interferometer for sensing the acoustic signal propagating in the medium.
claim 1
18. A flaw detection system using acoustic Doppler effect for detecting surface flaws in a medium wherein there is relative motion between the medium and system comprising:
acoustic transducer means, spaced from the medium to be inspected, for transmitting an acoustic signal to and receiving the reflected acoustic signal at a predetermined frequency from the surface of the medium to be inspected; and
means, responsive to the reflected acoustic signal, for distinguishing the Doppler shifted frequency in the reflected acoustic signal from the predetermined frequency of the transmitted acoustic signal representative of a surface flaw in the medium.
19. A flaw detection system using acoustic Doppler effect for detecting flaws in a medium wherein there is relative motion between the medium and system comprising:
transducer means, spaced from the medium to be inspected, for inducing an acoustic signal to propagate in the medium at a predetermined frequency and sensing the propagating acoustic signal in the medium; and
means, responsive to the sensed propagating acoustic signal, for distinguishing the Doppler shifted frequency representative of a flaw in the medium.
20. The flaw detection system using acoustic Doppler effect for detecting flaws of in which said transducer means includes an electromagnetic acoustic transducer for inducing and sensing the acoustic signal.
claim 19
21. The flaw detection system using acoustic Doppler effect for detecting flaws of in which said transducer means includes a transmitter and a receiver and said transmitter includes a laser for locally heating the medium to generate acoustic signals.
claim 19
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/770,323 US6324912B1 (en) | 1998-02-24 | 2001-01-26 | Flaw detection system using acoustic doppler effect |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/028,536 US6715354B2 (en) | 1998-02-24 | 1998-02-24 | Flaw detection system using acoustic doppler effect |
US09/770,323 US6324912B1 (en) | 1998-02-24 | 2001-01-26 | Flaw detection system using acoustic doppler effect |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/028,536 Division US6715354B2 (en) | 1998-02-24 | 1998-02-24 | Flaw detection system using acoustic doppler effect |
Publications (2)
Publication Number | Publication Date |
---|---|
US20010045130A1 true US20010045130A1 (en) | 2001-11-29 |
US6324912B1 US6324912B1 (en) | 2001-12-04 |
Family
ID=21843991
Family Applications (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/028,536 Expired - Fee Related US6715354B2 (en) | 1998-02-24 | 1998-02-24 | Flaw detection system using acoustic doppler effect |
US09/770,323 Expired - Fee Related US6324912B1 (en) | 1998-02-24 | 2001-01-26 | Flaw detection system using acoustic doppler effect |
US09/770,319 Expired - Fee Related US6854333B2 (en) | 1998-02-24 | 2001-01-26 | Flaw detection system using acoustic doppler effect |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/028,536 Expired - Fee Related US6715354B2 (en) | 1998-02-24 | 1998-02-24 | Flaw detection system using acoustic doppler effect |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/770,319 Expired - Fee Related US6854333B2 (en) | 1998-02-24 | 2001-01-26 | Flaw detection system using acoustic doppler effect |
Country Status (2)
Country | Link |
---|---|
US (3) | US6715354B2 (en) |
WO (1) | WO1999044029A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2005095885A1 (en) * | 2004-03-31 | 2005-10-13 | Force Technology | Noise reduction of laser ultrasound detection system |
US20070246612A1 (en) * | 2004-06-02 | 2007-10-25 | Patko Sandor M | Processing of Railway Track Data |
US20070277974A1 (en) * | 2006-05-18 | 2007-12-06 | Baker Hughes Incorporated | Pressure sensor utilizing a low thermal expansion material |
US20110192683A1 (en) * | 2007-08-17 | 2011-08-11 | Karl Weinberger | Elevator system with support means state detecting device and method for detecting a state of a support means |
Families Citing this family (57)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
ZA985834B (en) * | 1997-07-21 | 1999-01-14 | Henkel Corp | Method for reinforcing structural members |
US6715354B2 (en) | 1998-02-24 | 2004-04-06 | Massachusetts Institute Of Technology | Flaw detection system using acoustic doppler effect |
US6728515B1 (en) | 2000-02-16 | 2004-04-27 | Massachusetts Institute Of Technology | Tuned wave phased array |
US6833554B2 (en) * | 2000-11-21 | 2004-12-21 | Massachusetts Institute Of Technology | Laser-induced defect detection system and method |
US6612172B2 (en) * | 2001-03-05 | 2003-09-02 | Lucent Technologies Inc. | Sol-gel tube crack detection apparatus and method |
US6732545B2 (en) * | 2001-05-10 | 2004-05-11 | Lucent Technologies Inc. | Silica structure crack monitoring |
US20030014199A1 (en) * | 2001-07-12 | 2003-01-16 | Patrick Toomey | System and methods for detecting fault in structure |
US6732587B2 (en) * | 2002-02-06 | 2004-05-11 | Lockheed Martin Corporation | System and method for classification of defects in a manufactured object |
US10308265B2 (en) | 2006-03-20 | 2019-06-04 | Ge Global Sourcing Llc | Vehicle control system and method |
US9733625B2 (en) | 2006-03-20 | 2017-08-15 | General Electric Company | Trip optimization system and method for a train |
US6700528B2 (en) | 2002-09-27 | 2004-03-02 | The United States Of America As Represented By The Secretary Of The Army | Motion detection and alerting system |
US6742392B2 (en) | 2002-10-29 | 2004-06-01 | General Electric Company | Method and apparatus for inducing ultrasonic waves into railroad rails |
US6945114B2 (en) * | 2002-11-25 | 2005-09-20 | The Johns Hopkins University | Laser-air, hybrid, ultrasonic testing of railroad tracks |
US6862936B2 (en) * | 2002-11-27 | 2005-03-08 | The Johns Hopkins University | Laser-air, hybrid, ultrasonic testing of railroad wheels |
US9950722B2 (en) | 2003-01-06 | 2018-04-24 | General Electric Company | System and method for vehicle control |
ITUD20030019A1 (en) * | 2003-01-28 | 2004-07-29 | Danieli Automation Spa | PROCEDURE AND DEVICE FOR THE CONTROL OF STRAIGHTNESS AND TORSION OF LONG PRODUCTS. |
US7516662B2 (en) * | 2004-01-26 | 2009-04-14 | Force Technology | Detecting rail defects |
US9956974B2 (en) | 2004-07-23 | 2018-05-01 | General Electric Company | Vehicle consist configuration control |
US7987718B2 (en) * | 2004-12-20 | 2011-08-02 | Mayo Foundation For Medical Education And Research | Vibroacoustic system for vibration testing |
US20060201253A1 (en) * | 2005-03-14 | 2006-09-14 | Transportation Technology Center, Inc. | System for non-contact interrogation of railroad axles using laser-based ultrasonic inspection |
US9828010B2 (en) | 2006-03-20 | 2017-11-28 | General Electric Company | System, method and computer software code for determining a mission plan for a powered system using signal aspect information |
SE530696C2 (en) * | 2006-12-19 | 2008-08-19 | Radarbolaget I Gaevle Ab | Method and apparatus for detecting movement of the surface of an object |
US8914171B2 (en) | 2012-11-21 | 2014-12-16 | General Electric Company | Route examining system and method |
US8322221B1 (en) | 2009-03-26 | 2012-12-04 | The United States Of America As Represented By The Secretary Of The Air Force | Non-contact high resolution near field acoustic imaging system |
WO2010138603A2 (en) * | 2009-05-27 | 2010-12-02 | Ofi Testing Equipment, Inc. | Testing apparatus and method |
US8109474B2 (en) * | 2009-11-27 | 2012-02-07 | Bartek Peter M | Dual ultrasonic train detector |
US8222567B2 (en) | 2010-05-12 | 2012-07-17 | General Electric Company | System and method for laser shock peening |
JP2012047607A (en) * | 2010-08-27 | 2012-03-08 | Hitachi Ltd | Internal flaw detection method and device for the same |
DE102011006391A1 (en) | 2011-03-30 | 2012-10-04 | Siemens Aktiengesellschaft | Method and device for detecting parameters of a continuous or circulating material web in a material processing machine |
WO2013070455A1 (en) | 2011-11-10 | 2013-05-16 | The Regents Of The University Of California | Stress detection in rail |
CN102565198B (en) * | 2011-12-27 | 2014-07-02 | 华南理工大学 | Wireless ultrasonic probe assembly for flaw detection of crawler-type steel rail and flaw detection method of wireless ultrasonic probe assembly |
US9950715B2 (en) * | 2012-04-06 | 2018-04-24 | The Regents Of The University Of California | Air-coupled ultrasonic inspection of rails |
AU2013299501B2 (en) | 2012-08-10 | 2017-03-09 | Ge Global Sourcing Llc | Route examining system and method |
US9178755B2 (en) | 2012-11-14 | 2015-11-03 | Telefonaktiebolaget L M Ericsson (Publ) | Time-based link fault localization |
US9002197B2 (en) | 2012-11-14 | 2015-04-07 | Telefonaktiebolaget L M Ericsson (Publ) | Sequence-based link fault localization |
US9989498B2 (en) | 2013-02-06 | 2018-06-05 | The Regents Of The University Of California | Nonlinear ultrasonic testing for non-destructive measurement of longitudinal thermal stresses in solids |
US9094907B2 (en) | 2013-02-11 | 2015-07-28 | Telefonaktiebolaget L M Ericsson (Publ) | High-precision time tagging for content synthesization |
US8995667B2 (en) | 2013-02-21 | 2015-03-31 | Telefonaktiebolaget L M Ericsson (Publ) | Mechanism for co-ordinated authentication key transition for IS-IS protocol |
US9164065B2 (en) | 2013-03-12 | 2015-10-20 | Telefonaktiebolaget L M Ericsson (Publ) | Automated fault localization in pipelines and electrical power transmission lines |
US9255913B2 (en) | 2013-07-31 | 2016-02-09 | General Electric Company | System and method for acoustically identifying damaged sections of a route |
CA2893007C (en) | 2015-01-19 | 2020-04-28 | Tetra Tech, Inc. | Sensor synchronization apparatus and method |
CA2892952C (en) | 2015-01-19 | 2019-10-15 | Tetra Tech, Inc. | Protective shroud |
US10349491B2 (en) | 2015-01-19 | 2019-07-09 | Tetra Tech, Inc. | Light emission power control apparatus and method |
US10362293B2 (en) | 2015-02-20 | 2019-07-23 | Tetra Tech, Inc. | 3D track assessment system and method |
US10151731B2 (en) * | 2015-11-13 | 2018-12-11 | The Boeing Comapny | Ultrasonic system for nondestructive testing |
CA2955105A1 (en) * | 2016-01-20 | 2017-07-20 | Vector Corrosion Services, Inc. | Evaluating railway ties |
AU2017238169B2 (en) | 2016-03-21 | 2022-02-24 | Railpod, Inc. | Combined passive and active method and systems to detect and measure internal flaws within metal rails |
US11377130B2 (en) | 2018-06-01 | 2022-07-05 | Tetra Tech, Inc. | Autonomous track assessment system |
US10807623B2 (en) | 2018-06-01 | 2020-10-20 | Tetra Tech, Inc. | Apparatus and method for gathering data from sensors oriented at an oblique angle relative to a railway track |
US10730538B2 (en) | 2018-06-01 | 2020-08-04 | Tetra Tech, Inc. | Apparatus and method for calculating plate cut and rail seat abrasion based on measurements only of rail head elevation and crosstie surface elevation |
US10625760B2 (en) | 2018-06-01 | 2020-04-21 | Tetra Tech, Inc. | Apparatus and method for calculating wooden crosstie plate cut measurements and rail seat abrasion measurements based on rail head height |
CA3110960A1 (en) * | 2018-08-30 | 2020-03-05 | Voestalpine Signaling Usa Inc. | Railcar acoustic monitoring system and method of use |
US11254336B2 (en) | 2018-12-19 | 2022-02-22 | Nordco Inc. | Rail flaw detector |
WO2020232431A1 (en) | 2019-05-16 | 2020-11-19 | Tetra Tech, Inc. | System and method for generating and interpreting point clouds of a rail corridor along a survey path |
CN110274958A (en) * | 2019-07-22 | 2019-09-24 | 南昌航空大学 | Non-fragment orbit board checking device based on Air Coupling ultrasound |
RU2720043C1 (en) * | 2019-11-06 | 2020-04-23 | Открытое акционерное общество "Радиоавионика" | High-speed ultrasonic flaw detection using the doppler effect |
RU2722089C1 (en) * | 2019-12-04 | 2020-05-26 | Открытое акционерное общество "Радиоавионика" | Noncontact ultrasonic flaw detection using a doppler effect |
Family Cites Families (106)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3564488A (en) | 1969-06-16 | 1971-02-16 | Hitachi Ltd | Speed measuring device of moving objects |
US3829827A (en) | 1971-05-28 | 1974-08-13 | Thomson Csf | Acoustical holography system for acoustic image conversion |
US3812708A (en) | 1971-11-17 | 1974-05-28 | Scanning Sys Inc | Method and apparatus for testing wheels and defect detection in wheels |
US3937068A (en) | 1974-02-25 | 1976-02-10 | Joy Ivan L | Transducer arrangement for ultrasonic rail tester coupling carriages |
US3962908A (en) | 1974-02-25 | 1976-06-15 | Joy Ivan L | Transducer arrangement for ultrasonic rail tester coupling carriages |
US4004455A (en) | 1975-05-23 | 1977-01-25 | Teleweld, Inc. | Flaw detecting apparatus for railroad rails and the like |
US3978713A (en) | 1975-05-27 | 1976-09-07 | General Electric Company | Laser generation of ultrasonic waves for nondestructive testing |
US4174636A (en) | 1977-07-25 | 1979-11-20 | Pagano Dominick A | Two wheel ultrasonic rail testing system and method |
US4127035A (en) | 1977-09-02 | 1978-11-28 | Rockwell International Corporation | Electromagnetic transducer |
GB2008756B (en) | 1977-09-30 | 1982-07-14 | Ti Group Services Ltd | Ultrasonic inspection |
US4143553A (en) | 1977-12-19 | 1979-03-13 | Automation Industries, Inc. | Contoured search unit for detecting internal flaws |
US4338822A (en) | 1978-06-20 | 1982-07-13 | Sumitomo Metal Industries, Ltd. | Method and apparatus for non-contact ultrasonic flaw detection |
US4248092A (en) | 1979-04-25 | 1981-02-03 | Electric Power Research Institute, Inc. | Method and apparatus for efficiently generating elastic waves with a transducer |
DE2926173A1 (en) | 1979-06-28 | 1981-01-15 | Siemens Ag | METHOD FOR DESTRUCTION-FREE MATERIAL TESTING WITH ULTRASONIC IMPULSES |
US4435984A (en) | 1980-04-21 | 1984-03-13 | Southwest Research Institute | Ultrasonic multiple-beam technique for detecting cracks in bimetallic or coarse-grained materials |
US4570487A (en) | 1980-04-21 | 1986-02-18 | Southwest Research Institute | Multibeam satellite-pulse observation technique for characterizing cracks in bimetallic coarse-grained component |
US4372163A (en) | 1981-02-03 | 1983-02-08 | Rockwell International Corporation | Acoustic measurement of near surface property gradients |
JPS58131557A (en) * | 1982-01-12 | 1983-08-05 | Nippon Steel Corp | Non-contact measuring method for ultrasonic wave |
US4497210A (en) | 1982-07-05 | 1985-02-05 | Tokyo Shibaura Denki Kabushiki Kaisha | Phased array ultrasonic testing apparatus and testing method therefor |
US4487071A (en) | 1982-09-22 | 1984-12-11 | Dapco Industries, Inc. | Flaw detection system for railroad rails and the like |
US4437031A (en) | 1982-09-30 | 1984-03-13 | Purdue Research Foundation | ZnO/Si SAW Device having separate comb transducer |
US4481822A (en) | 1982-10-18 | 1984-11-13 | Hitachi, Ltd. | Synthetic aperture ultrasonic testing apparatus with shear and longitudinal wave modes |
US4541280A (en) | 1982-12-28 | 1985-09-17 | Canadian Patents & Development Ltd. | Efficient laser generation of surface acoustic waves |
US4523469A (en) | 1983-01-19 | 1985-06-18 | The United States Of America As Represented By The Secretary Of The Navy | Laser generation of ultrasonic waveform reconstructions |
US4512197A (en) | 1983-09-01 | 1985-04-23 | The United States Of America As Represented By The Secretary Of The Navy | Apparatus for generating a focusable and scannable ultrasonic beam for non-destructive examination |
US4567769A (en) | 1984-03-08 | 1986-02-04 | Rockwell International Corporation | Contact-free ultrasonic transduction for flaw and acoustic discontinuity detection |
GB8422282D0 (en) | 1984-09-04 | 1984-10-10 | Atomic Energy Authority Uk | Lamb wave guide |
CA1224935A (en) * | 1984-11-28 | 1987-08-04 | Her Majesty The Queen, In Right Of Canada, As Represented By The Ministe R Of The National Research Council And The Minister Of Energy, Mines And Resources | Optical interferometric reception of ultrasonic energy |
GB8509836D0 (en) | 1985-04-17 | 1985-05-22 | Rolls Royce | Transient stress wave events |
WO1986006486A1 (en) | 1985-04-22 | 1986-11-06 | Hitachi Construction Machinery Co., Ltd. | Method of measuring angle of inclination of planar flaw in solid object with ultrasonic wave |
US4633715A (en) * | 1985-05-08 | 1987-01-06 | Canadian Patents And Development Limited - Societe Canadienne Des Brevets Et D'exploitation Limitee | Laser heterodyne interferometric method and system for measuring ultrasonic displacements |
CH665909A5 (en) | 1985-05-15 | 1988-06-15 | Matix Ind Sa | METHOD AND DEVICE FOR ULTRASONIC DETECTION OF INTERNAL DEFECTS OF A RAILWAY RAIL LOCATED IN THE EDGE OF THE MUSHROOM OF THAT RAIL, USE OF THE DEVICE. |
US4866614A (en) | 1985-12-26 | 1989-09-12 | General Electric Company | Ultrasound characterization of 3-dimensional flaws |
JPH063440B2 (en) | 1986-10-06 | 1994-01-12 | 新日本製鐵株式会社 | Ultrasonic flaw detection method and device for welded steel pipe |
US4834111A (en) * | 1987-01-12 | 1989-05-30 | The Trustees Of Columbia University In The City Of New York | Heterodyne interferometer |
WO1989008336A1 (en) | 1988-02-29 | 1989-09-08 | The Regents Of The University Of California | Plate-mode ultrasonic sensor |
US5212988A (en) | 1988-02-29 | 1993-05-25 | The Reagents Of The University Of California | Plate-mode ultrasonic structure including a gel |
US4932618A (en) | 1989-04-11 | 1990-06-12 | Rockwell International Corporation | Sonic track condition determination system |
US5154081A (en) | 1989-07-21 | 1992-10-13 | Iowa State University Research Foundation, Inc. | Means and method for ultrasonic measurement of material properties |
US5035144A (en) | 1989-07-31 | 1991-07-30 | National Research Council Of Canada | Frequency broadband measurement of the characteristics of acoustic waves |
US5152010A (en) | 1989-12-29 | 1992-09-29 | American Nucleonics Corporation | Highly directive radio receiver employing relatively small antennas |
CH679847A5 (en) | 1990-01-12 | 1992-04-30 | Bruno Mueller | |
US5125108A (en) | 1990-02-22 | 1992-06-23 | American Nucleonics Corporation | Interference cancellation system for interference signals received with differing phases |
JPH0464350A (en) | 1990-07-04 | 1992-02-28 | Yokogawa Medical Syst Ltd | Ultrasonic imaging apparatus |
US5079070A (en) | 1990-10-11 | 1992-01-07 | International Business Machines Corporation | Repair of open defects in thin film conductors |
US5438872A (en) | 1991-06-21 | 1995-08-08 | Canon Kabushiki Kaisha | Measuring method and apparatus using a lamb wave |
US5303240A (en) | 1991-07-08 | 1994-04-12 | Motorola, Inc. | Telecommunications system using directional antennas |
AT398414B (en) | 1991-11-13 | 1994-12-27 | Plasser Bahnbaumasch Franz | MEASURING ARRANGEMENT FOR CONTINUOUS MEASURING OF WAVEOUS RUNNINGS OF A RAIL |
DE69126329T2 (en) * | 1991-11-22 | 1997-11-20 | Doryokuro Kakunenryo | METHOD AND DEVICE FOR LASER ULTRASONIC ERROR TESTING |
US5172343A (en) | 1991-12-06 | 1992-12-15 | General Electric Company | Aberration correction using beam data from a phased array ultrasonic scanner |
US5257544A (en) | 1992-01-22 | 1993-11-02 | The Board Of Trustees Of The Leland Stanford Junior University | Resonant frequency method for bearing ball inspection |
US5386727A (en) | 1992-06-02 | 1995-02-07 | Herzog Contracting Corporation | Dynamic rail longitudinal stress measuring system |
US5341683A (en) | 1992-06-02 | 1994-08-30 | Searle Donald S | Dynamic rail longitudinal stress measuring system |
JP3347766B2 (en) | 1992-06-08 | 2002-11-20 | 日本トムソン株式会社 | Linear encoder and guide unit having the same |
US5549003A (en) | 1992-10-21 | 1996-08-27 | The United States Of America As Represented By The Secretary Of Commerce | Method and apparatus for visualization of internal stresses in solid non-transparent materials by ultrasonic techniques and ultrasonic computer tomography of stress |
US5488737A (en) | 1992-11-17 | 1996-01-30 | Southwestern Bell Technology Resources, Inc. | Land-based wireless communications system having a scanned directional antenna |
EP0603608B1 (en) | 1992-12-23 | 1997-07-23 | Speno International S.A. | Method and apparatus for continuous non-destructive ultrasonic testing of railway rails |
US5419196A (en) | 1993-03-19 | 1995-05-30 | Pandrol Jackson Technologies, Inc. | Ultrasonic side-looker for rail head flaw detection |
US5574989A (en) | 1993-04-26 | 1996-11-12 | Hughes Electronics | Time division multiple access cellular communication system and method employing base station diversity transmission |
WO1994029714A1 (en) * | 1993-06-07 | 1994-12-22 | Nkk Corporation | Method and apparatus for processing signals of ultrasonic flaw detector |
US5402235A (en) | 1993-07-01 | 1995-03-28 | National Research Council Of Canada | Imaging of ultrasonic-surface motion by optical multiplexing |
CA2144597C (en) * | 1994-03-18 | 1999-08-10 | Paul J. Latimer | Improved emat probe and technique for weld inspection |
EP0676322B1 (en) | 1994-04-06 | 1998-05-13 | Speno International S.A. | Ultrasonic measuring device of defaults of a railway rail |
JP2778619B2 (en) | 1994-06-09 | 1998-07-23 | 東日本旅客鉄道株式会社 | Non-contact speed measurement device for railway vehicles |
US5439157A (en) * | 1994-07-18 | 1995-08-08 | The Babcock & Wilcox Company | Automated butt weld inspection system |
US5685308A (en) | 1994-08-05 | 1997-11-11 | Acuson Corporation | Method and apparatus for receive beamformer system |
US5665907A (en) * | 1994-09-06 | 1997-09-09 | The University Of Chicago | Ultrasonic imaging system for in-process fabric defect detection |
US5672830A (en) * | 1994-10-04 | 1997-09-30 | Massachusetts Institute Of Technology | Measuring anisotropic mechanical properties of thin films |
SE504576C2 (en) * | 1994-10-06 | 1997-03-10 | Lorentzen & Wettre Ab | Device for measuring ultrasound the elastic properties of a moving web of paper |
GB9517794D0 (en) | 1994-10-20 | 1995-11-01 | Imperial College | Inspection of pipes |
CA2169307C (en) * | 1994-12-12 | 2003-10-14 | David A. Hutchins | Non-contact characterization and inspection of materials using wideband air coupled ultrasound |
US5629485A (en) | 1994-12-13 | 1997-05-13 | The B.F. Goodrich Company | Contaminant detection sytem |
AU4899196A (en) | 1995-01-17 | 1996-08-07 | Penn State Research Foundation, The | Bore probe for tube inspection with guided waves and method therefor |
US5634936A (en) | 1995-02-06 | 1997-06-03 | Scimed Life Systems, Inc. | Device for closing a septal defect |
DE19511751C2 (en) | 1995-03-30 | 1998-07-09 | Siemens Ag | Process for the reconstruction of signals disturbed by multipath propagation |
US5698787A (en) | 1995-04-12 | 1997-12-16 | Mcdonnell Douglas Corporation | Portable laser/ultrasonic method for nondestructive inspection of complex structures |
US5684592A (en) | 1995-06-07 | 1997-11-04 | Hughes Aircraft Company | System and method for detecting ultrasound using time-delay interferometry |
US5578758A (en) | 1995-06-21 | 1996-11-26 | Pandrol Jackson Technologies, Inc. | Rail investigating ultrasonic transducer |
US5763785A (en) | 1995-06-29 | 1998-06-09 | Massachusetts Institute Of Technology | Integrated beam forming and focusing processing circuit for use in an ultrasound imaging system |
US5804727A (en) * | 1995-09-01 | 1998-09-08 | Sandia Corporation | Measurement of physical characteristics of materials by ultrasonic methods |
JP3465434B2 (en) * | 1995-09-06 | 2003-11-10 | ソニー・プレシジョン・テクノロジー株式会社 | Laser doppler speedometer |
US5608166A (en) | 1995-10-12 | 1997-03-04 | National Research Council Of Canada | Generation and detection of ultrasound with long pulse lasers |
US5646350A (en) * | 1996-01-23 | 1997-07-08 | Computational Systems Inc. | Monitoring slow speed machinery using integrator and selective correction of frequency spectrum |
US5650852A (en) | 1996-03-08 | 1997-07-22 | The Boeing Company | Temperature-compensated laser measuring method and apparatus |
US5767410A (en) | 1996-03-19 | 1998-06-16 | Combustion Engineering, Inc. | Lamb wave ultrasonic probe for crack detection and measurement in thin-walled tubing |
JP3519742B2 (en) | 1996-03-28 | 2004-04-19 | 三菱電機株式会社 | Ultrasonic flaw detector and ultrasonic flaw detection method |
US5801312A (en) | 1996-04-01 | 1998-09-01 | General Electric Company | Method and system for laser ultrasonic imaging of an object |
US5724138A (en) | 1996-04-18 | 1998-03-03 | Textron Systems Corporation | Wavelet analysis for laser ultrasonic measurement of material properties |
US5627508A (en) | 1996-05-10 | 1997-05-06 | The United States Of America As Represented By The Secretary Of The Navy | Pilot vehicle which is useful for monitoring hazardous conditions on railroad tracks |
US5814730A (en) * | 1996-06-10 | 1998-09-29 | Institute Of Paper Science And Technology And Georgia Institute Of Technology | Material characteristic testing method and apparatus using interferometry to detect ultrasonic signals in a web |
US5760904A (en) | 1996-07-26 | 1998-06-02 | General Electric Company | Method and system for inspecting a surface of an object with laser ultrasound |
JP3526196B2 (en) | 1997-01-07 | 2004-05-10 | 株式会社東芝 | Adaptive antenna |
US5818592A (en) * | 1997-02-07 | 1998-10-06 | Phase Metrics, Inc. | Non-contact optical glide tester |
US5930293A (en) | 1997-03-10 | 1999-07-27 | Lucent Technologies Inc. | Method and apparatus for achieving antenna receive diversity with wireless repeaters |
US5926503A (en) | 1997-08-27 | 1999-07-20 | Motorola, Inc. | DS-CDMA receiver and forward link diversity method |
JPH11160926A (en) | 1997-12-01 | 1999-06-18 | Matsushita Electric Ind Co Ltd | Image forming device |
TW444205B (en) | 1998-02-09 | 2001-07-01 | Siemens Power Corp | Method for the inspection of nuclear fuel rod for fretting and wear within a nuclear fuel assembly |
US6715354B2 (en) | 1998-02-24 | 2004-04-06 | Massachusetts Institute Of Technology | Flaw detection system using acoustic doppler effect |
US6067391A (en) | 1998-09-02 | 2000-05-23 | The United States Of America As Represented By The Secretary Of The Air Force | Multiply periodic refractive index modulated optical filters |
US6186004B1 (en) | 1999-05-27 | 2001-02-13 | The Regents Of The University Of California | Apparatus and method for remote, noninvasive characterization of structures and fluids inside containers |
US6128092A (en) | 1999-07-13 | 2000-10-03 | National Research Council Of Canada | Method and system for high resolution ultrasonic imaging of small defects or anomalies. |
US6253618B1 (en) | 1999-12-08 | 2001-07-03 | Massachusetts Intitute Of Technology | Apparatus and method for synthetic phase tuning of acoustic guided waves |
US6351586B1 (en) | 1999-12-29 | 2002-02-26 | Corning Incorporated | Wavelength dependent phase delay device |
US6382028B1 (en) | 2000-02-23 | 2002-05-07 | Massachusetts Institute Of Technology | Ultrasonic defect detection system |
US6360609B1 (en) | 2000-02-23 | 2002-03-26 | Massachusetts Institute Of Technology | Method and system for interpreting and utilizing multimode dispersive acoustic guided waves |
US6833554B2 (en) | 2000-11-21 | 2004-12-21 | Massachusetts Institute Of Technology | Laser-induced defect detection system and method |
-
1998
- 1998-02-24 US US09/028,536 patent/US6715354B2/en not_active Expired - Fee Related
-
1999
- 1999-02-23 WO PCT/US1999/003871 patent/WO1999044029A1/en active Application Filing
-
2001
- 2001-01-26 US US09/770,323 patent/US6324912B1/en not_active Expired - Fee Related
- 2001-01-26 US US09/770,319 patent/US6854333B2/en not_active Expired - Fee Related
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2005095885A1 (en) * | 2004-03-31 | 2005-10-13 | Force Technology | Noise reduction of laser ultrasound detection system |
US20080007717A1 (en) * | 2004-03-31 | 2008-01-10 | Force Technology | Noise Reduction Of Laser Ultrasound Detection System |
US20070246612A1 (en) * | 2004-06-02 | 2007-10-25 | Patko Sandor M | Processing of Railway Track Data |
US20070277974A1 (en) * | 2006-05-18 | 2007-12-06 | Baker Hughes Incorporated | Pressure sensor utilizing a low thermal expansion material |
US7703328B2 (en) * | 2006-05-18 | 2010-04-27 | Baker Hughes Incorporated | Pressure sensor utilizing a low thermal expansion material |
US20110192683A1 (en) * | 2007-08-17 | 2011-08-11 | Karl Weinberger | Elevator system with support means state detecting device and method for detecting a state of a support means |
Also Published As
Publication number | Publication date |
---|---|
US6324912B1 (en) | 2001-12-04 |
US20010020390A1 (en) | 2001-09-13 |
US6854333B2 (en) | 2005-02-15 |
US6715354B2 (en) | 2004-04-06 |
WO1999044029A1 (en) | 1999-09-02 |
US20010015104A1 (en) | 2001-08-23 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6324912B1 (en) | Flaw detection system using acoustic doppler effect | |
US6945114B2 (en) | Laser-air, hybrid, ultrasonic testing of railroad tracks | |
Edwards et al. | Characterisation of defects in the railhead using ultrasonic surface waves | |
EP0204143B1 (en) | Method and apparatus for the ultrasonic detection of internal faults in the edges of the head of a railway rail | |
Zumpano et al. | A new damage detection technique based on wave propagation for rails | |
CN101398411B (en) | Rail tread defect rapid scanning and detecting method and device thereof | |
WO2006099397A2 (en) | System for non-contact interrogation of railroad axles using laser-based ultrasonic inspection | |
CN104960546A (en) | Flaw detecting car for inspecting steel rails of high-speed rail | |
Kenderian et al. | Laser based and air coupled ultrasound as noncontact and remote techniques for testing of railroad tracks | |
GB2383413A (en) | Detecting rail defects using acoustic surface waves | |
di Scalea et al. | Ultrasonic NDE of railroad tracks: air-coupled cross-sectional inspection and long-range inspection | |
Santa-aho et al. | Automated ultrasound-based inspection of rails | |
RU2487809C2 (en) | Method of track and rolling stock diagnostics | |
GB2398946A (en) | Microwave radar detection of surface discontinuities | |
Cheng et al. | Assessment of ultrasonic NDT methods for high speed rail inspection | |
USH924H (en) | Signal analysis in leaky lamb wave nde technique | |
Kenderian et al. | Rail track field testing using laser/air hybrid ultrasonic technique | |
RU2652511C1 (en) | Method of micro cracks on the rail head rolling surface ultrasonic detection | |
di Scalea et al. | High-speed defect detection in rails by noncontact guided ultrasonic testing | |
Brizuela et al. | Railway wheels flat detector using Doppler effect | |
Armitage | The use of low-frequency Rayleigh waves to detect gauge corner cracking in railway lines | |
RU2511644C1 (en) | Acoustic method of rail track failure detection | |
Wang et al. | Investigation and study for rail internal-flaw inspection technique | |
Fadaeifard et al. | Rail inspection technique employing advanced nondestructive testing and Structural Health Monitoring (SHM) approaches—A review | |
Han et al. | Development of novel rail non-destructive inspection technologies |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
REMI | Maintenance fee reminder mailed | ||
LAPS | Lapse for failure to pay maintenance fees | ||
STCH | Information on status: patent discontinuation |
Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362 |
|
FP | Lapsed due to failure to pay maintenance fee |
Effective date: 20051204 |