US4246793A
Expired / Lapsed
US
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Nondestructive testing
Assignee: Battelle Memorial Institute Inc
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Filing: 1979-02-08
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Granted: 1981-01-27
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Expires: 1999-02-08
Abstract
Abstract Methods (and apparatus) for nondestructively testing a body of material having a surface in contact with a gaseous environment (e.g. air, nitrogen, or inert gas), that comprise (A) the step of (and means for) directing to a region at the surface of the body a pulse of laser radiation having sufficient energy density and sufficiently long wavelength to initiate in the adjacent gas a blast wave that impinges on the surface and provides an ultrasonic wave in the body, and (B) the further step of (and means for) detecting a portion of the ultrasonic wave that has been affected by the body. The radiation directing means typically comprises a laser that provides a pulse having a duration of about 0.01 to 10 microseconds, and means for focusing the pulse to provide an energy density of at least about 5 Joules per square centimeter. The detecting means typically comprises an electromagnetic or capacitive transducer.
Inventors
- 👤 Barry P. Fairand
- 👤 Matthew J. Golis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 00:14
CPC Classifications
G; G01; G01N; G01N29/00; G01N29/22; G01N29/24; G01N29/2412; G01N29/2418
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
80 words
A method of nondestructively testing a body of material having a surface in contact with a gaseous environment, that comprises directing to a region at the surface of the body a pulse of laser radiation having sufficient energy density and sufficiently long wavelength to initiate in the adjacent gas a blast wave that impinges on the surface and provides an ultrasonic wave in the body, and detecting a portion of the ultrasonic wave that has been affected by the body.
Claim 2
Independent Claim
80 words
A method of nondestructively testing a body of material having a surface in contact with a gaseous environment, that comprises directing to a region at the surface of the body a pulse of laser radiation having sufficient energy density and sufficiently long wavelength to initiate in the adjacent gas a blast wave that impinges on the surface and provides an ultrasonic wave in the body, and detecting a portion of the ultrasonic wave that has been affected by the body.
Claim 3
Dependent Claim
72 words
A method as in claim 1, wherein the energy density of the radiation is at least about 5 Joules per square centimeter with a wavelength of about 10.6 micrometers; at least about 50 Joules per square centimeter with a wavelength of about 1.06 micrometers; and at least about an energy density interpolated or extrapolated from the foregoing energy densities with another wavelength, with the energy density approximately inversely proportional to the wavelength.
Claim 4
Dependent Claim
18 words
A method as in claim 2, wherein the surface region area is at least about 0.1 square millimeter.
Claim 5
Dependent Claim
72 words
A method as in claim 1, wherein the energy density of the radiation is at least about 10 Joules per square centimeter with a wavelength of about 10.6 micrometers; at least about 100 Joules per square centimeter with a wavelength of about 1.06 micrometers; and at least about an energy density interpolated or extrapolated from the foregoing energy densities with another wavelength, with the energy density approximately inversely proportional to the wavelength.
Claim 6
Dependent Claim
17 words
A method as in claim 1, wherein the gas comprises essentially air, nitrogen, or an inert gas.
Claim 7
Dependent Claim
19 words
A method as in claim 1, wherein the region has an area of about 0.1 to 10 square centimeters.
Claim 8
Dependent Claim
18 words
A method as in claim 1, wherein the wavelength of the radiation is about 1 to 15 micrometers.
Claim 9
Dependent Claim
18 words
A method as in claim 1, wherein the duration of the pulse is about 0.01 to 10 microseconds.
Claim 10
Dependent Claim
20 words
A method as in claim 1, wherein the fundamental frequency of the ultrasonic wave is about 0.1 to 20 megahertz.
Claim 11
Dependent Claim
27 words
A method as in claim 1, wherein the detecting includes providing a visible record indicative of the location of a surface or other discontinuity in the body.
Claim 12
Independent Claim
109 words
A method of nondescructively testing a body of material having an electrically conductive surface in contact with a gaseous environment, that comprises directing to a region at the surface of the body a pulse of laser radiation having sufficient energy density and sufficiently long wavelength to initiate in the adjacent gas a blast wave that impinges on the surface and provides an ultrasonic wave in the body, and detecting a portion of the ultrasonic wave that has been affected by the body using an electromagnetic transducer that is resonant at substantially the fundamental frequency of the ultrasonic wave and is located adjacent to the conductive surface and spaced therefrom.
Claim 13
Independent Claim
109 words
A method of nondescructively testing a body of material having an electrically conductive surface in contact with a gaseous environment, that comprises directing to a region at the surface of the body a pulse of laser radiation having sufficient energy density and sufficiently long wavelength to initiate in the adjacent gas a blast wave that impinges on the surface and provides an ultrasonic wave in the body, and detecting a portion of the ultrasonic wave that has been affected by the body using an electromagnetic transducer that is resonant at substantially the fundamental frequency of the ultrasonic wave and is located adjacent to the conductive surface and spaced therefrom.
Claim 14
Dependent Claim
15 words
A method as in claim 11, wherein the resonant frequency of the transducer is adjustable.
Claim 15
Dependent Claim
27 words
A method as in claim 11, wherein the transducer is maintained in its position at a substantially constant average spacing from the conductive surface during the testing.
Claim 16
Independent Claim
85 words
A method of nondestructively testing a body of material having a surface in contact with a gaseous environment, that comprises directing to each of a plurality of regions at the surface of the body a pulse of laser radiation having sufficient energy density and sufficiently long wavelength to initiate in the adjacent gas a blast wave that impinges on the surface and provides an ultrasonic wave in the body, and detecting a portion of each such ultrasonic wave that has been affected by the body.
Claim 17
Independent Claim
85 words
A method of nondestructively testing a body of material having a surface in contact with a gaseous environment, that comprises directing to each of a plurality of regions at the surface of the body a pulse of laser radiation having sufficient energy density and sufficiently long wavelength to initiate in the adjacent gas a blast wave that impinges on the surface and provides an ultrasonic wave in the body, and detecting a portion of each such ultrasonic wave that has been affected by the body.
Claim 18
Dependent Claim
32 words
A method as in claim 14, wherein the detecting is done with a plurality of transducers, each maintained in a different location adjacent to, and spaced from, a surface of the body.
Claim 19
Dependent Claim
115 words
Apparatus for nondestructively testing a body of material having an electrically conductive surface in contact with a gaseous environment, that comprises means for directing to a region at the surface of the body a pulse of laser radiation having sufficient energy density and sufficiently long wavelength to initiate in the adjacent gas a blast wave that impinges on the surface and provides an ultrasonic wave in the body, and means for detecting a portion of the ultrasonic wave that has been affected by the body, the detecting means comprising an electromagnetic transducer that is resonant at substantially the fundamental frequency of the ultrasonic wave and is located adjacent to the conductive surface and spaced therefrom.
Claim 20
Dependent Claim
115 words
Apparatus for nondestructively testing a body of material having an electrically conductive surface in contact with a gaseous environment, that comprises means for directing to a region at the surface of the body a pulse of laser radiation having sufficient energy density and sufficiently long wavelength to initiate in the adjacent gas a blast wave that impinges on the surface and provides an ultrasonic wave in the body, and means for detecting a portion of the ultrasonic wave that has been affected by the body, the detecting means comprising an electromagnetic transducer that is resonant at substantially the fundamental frequency of the ultrasonic wave and is located adjacent to the conductive surface and spaced therefrom.
Claim 21
Dependent Claim
14 words
Apparatus as in claim 16, wherein the resonant frequency of the transducer is adjustable.
Claim 22
Dependent Claim
28 words
Apparatus as in claim 16, comprising also means for maintaining the transducer in its position at a substantially constant average spacing from the conductive surface during the testing.
Claim 23
Dependent Claim
116 words
Apparatus for nondestructively testing a body of material having a surface in contact with a gaseous environment, that comprises means for directing to each of a plurality of regions at the surface of the body a pulse of laser radiation having sufficient energy density and sufficiently long wavelength to initiate in the adjacent gas a blast wave that impinges on the surface and provides an ultrasonic wave in the body, and means for detecting a portion of each such ultrasonic wave that has been affected by the body, the detecting means comprising a plurality of transducers and means for maintaining each transducer in a different location adjacent to, and spaced from, a surface of the body.
Claim 24
Dependent Claim
116 words
Apparatus for nondestructively testing a body of material having a surface in contact with a gaseous environment, that comprises means for directing to each of a plurality of regions at the surface of the body a pulse of laser radiation having sufficient energy density and sufficiently long wavelength to initiate in the adjacent gas a blast wave that impinges on the surface and provides an ultrasonic wave in the body, and means for detecting a portion of each such ultrasonic wave that has been affected by the body, the detecting means comprising a plurality of transducers and means for maintaining each transducer in a different location adjacent to, and spaced from, a surface of the body.
References Cited (Backward Citations)
US3978713A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-01-27 | 1984-07-28 | 1985-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-27 | 1988-07-28 | 1989-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-27 | 1992-07-28 | 1993-01-27 | $7700.00 | Window Closed / Lapsed |