Laser-air, hybrid, ultrasonic testing of railroad tracks
First Claim
1. A remote, non-contact system for detecting a defect in a structural material that is surrounded by a gaseous or vacuum environment, said system comprising:
- a remote means, located at a first specified location in said environment and spaced from said structural material, for generating, in a non-contact manner in said structural material, modes of ultrasonic stress waves having a specified, controlled wavefront and frequencies, a non-contact means, located at a second specified location in said environment and spaced from said structural material, for sensing from said structural material an acoustic signal in said environment that distinguishes the propagation of said modes of ultrasonic stress waves in said structural material, and a means, responsive to said sensed acoustic signal, for distinguishing in said sensed signal the differences between said modes of said ultrasonic stress waves so as to detect said defect in said structural materials, wherein said structural material is a metal in a complex-shaped form.
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Accused Products
Abstract
Formed Laser Sources (FLS) using pulsed laser light for generation of ultrasonic stress waves are combined with air-coupled detection of ultrasound to provide for the hybrid non-contact, dynamic and remote ultrasonic testing of structural materials, especially railroad tracks. Using this hybrid technique, multimode and controlled frequency and wavefront surface acoustic waves, plate waves, guided waves, and bulk waves are generated to propagate on and within the rail tracks. The non-contact, remote nature of this methodology enables high-speed, fill access inspections of rail tracks. The flexibility and remote nature of this methodology makes possible the detection of critical cracks that are not easy, or impossible to detect, with current inspection techniques available to the railroad industry.
65 Citations
17 Claims
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1. A remote, non-contact system for detecting a defect in a structural material that is surrounded by a gaseous or vacuum environment, said system comprising:
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a remote means, located at a first specified location in said environment and spaced from said structural material, for generating, in a non-contact manner in said structural material, modes of ultrasonic stress waves having a specified, controlled wavefront and frequencies, a non-contact means, located at a second specified location in said environment and spaced from said structural material, for sensing from said structural material an acoustic signal in said environment that distinguishes the propagation of said modes of ultrasonic stress waves in said structural material, and a means, responsive to said sensed acoustic signal, for distinguishing in said sensed signal the differences between said modes of said ultrasonic stress waves so as to detect said defect in said structural materials, wherein said structural material is a metal in a complex-shaped form. - View Dependent Claims (2, 3, 4, 5)
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6. A remote, non-contact method for detecting a defect in a structural material that is surrounded by a gaseous or vacuum environment, said method comprising the steps of:
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generating, in a non-contact manner in said structural material, modes of ultrasonic stress waves having a specified, controlled wavefront and frequencies, sensing from said structural material an acoustic signal in said environment that distinguishes the propagation of said modes of ultrasonic stress waves in said structural material, and distinguishing in said sensed signal the differences between said modes of said sensed ultrasonic stress waves so as to detect said defect, wherein said structural material is a metal in a complex-shaped form. - View Dependent Claims (7, 8, 9, 10)
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11. A remote, non-contact system for detecting a defect in a structural material that is surrounded by a gaseous or vacuum environment, said system comprising:
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a pulsed, laser light source, located at a first specified location in said environment and spaced from said structural material, for generating in said structural material, modes of ultrasonic stress waves, a lens in the path of the light from said light source for focusing said light into a specified illumination pattern to generate a controlled ultrasonic wavefront, an air-coupled transducer, located at a second specified location in said environment and spaced from said structural member, for sensing from said structural material an acoustic signal in said environment that distinguishes the propagation of said modes of ultrasonic stress waves in said structural material, and a signal processor, responsive to said sensed acoustic signal, for distinguishing in said sensed signal the differences between said modes of said ultrasonic stress waves so as to detect said defect, wherein said structural material is a metal in a complex-shaped form. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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Specification