Patent US4297885A successfully refreshed from Google Patents.
US4297885A
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Acoustic emission for detection and monitoring of crack initiation and propagation in materials
Assignee: ConocoPhillips Co
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Filing: 1979-10-24
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Granted: 1981-11-03
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Expires: 1999-10-24
Abstract
Abstract Initiation and propagation of cracks in materials is detected and monitored by (a) adhering an acoustical emitter to the area of the material to be monitored, and (b) monitoring for acoustical signals emitted by the adhered emitter, said signals produced by cracks in the material initiating in or propagating into the acoustical emitter. An acoustical emitter such as brittle plastic, glass rods or strips and metal such as tin or cadmium can be used.
Inventors
- 👤 Norman W. Hein, Jr.
- 👤 Donald H. Oertle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:50
CPC Classifications
G; G10; G10K; G10K15/00; G10K15/04; G01; G01H; G01H1/00; G01N; G01N29/00; G01N29/14
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
76 words
A method for detecting and monitoring initiation and propagation of cracks in materials comprising (a) adhering an acoustical emitter selected from the group consisting of brittle plastics, glass rods and strips, fiberglass, cadminum metal, tin metal, micarta, boron/epoxy reinforced strips, boron/aluminum reinforced strips, graphite/epoxy liminates and silicon carbide fiber laminates to the area to be monitored, and (b) monitoring for acoustical signals emitted by the adhered material, indicating crack initiation or propagation into the adhered material.
Claim 2
Independent Claim
76 words
A method for detecting and monitoring initiation and propagation of cracks in materials comprising (a) adhering an acoustical emitter selected from the group consisting of brittle plastics, glass rods and strips, fiberglass, cadminum metal, tin metal, micarta, boron/epoxy reinforced strips, boron/aluminum reinforced strips, graphite/epoxy liminates and silicon carbide fiber laminates to the area to be monitored, and (b) monitoring for acoustical signals emitted by the adhered material, indicating crack initiation or propagation into the adhered material.
Claim 3
Dependent Claim
15 words
A method as described in claim 1 wherein the material monitored is a structural material.
Claim 4
Dependent Claim
19 words
A method as described in claim 2 wherein the plurality of acoustical emitters are placed on the structural material.
Claim 5
Dependent Claim
30 words
A method as described in claim 3 wherein the acoustical emitter is bonded to the structural member with epoxy resins, silicone based adhesives, cyanoacrylate based adhesives, welding, brazing, or soldering.
Claim 6
Dependent Claim
18 words
A method as described in claim 4 wherein sensors are placed to receive emissions from all acoustical emitters.
Claim 7
Dependent Claim
25 words
A method as described in claim 5 wherein a plurality of sensors are monitored, said monitors being capable of indicating which sensors have been activated.
Claim 8
Dependent Claim
16 words
A method as described in claim 6 wherein the monitoring system records activity of each sensor.
Claim 9
Dependent Claim
17 words
A method as described in claim 7 wherein the acoustical emitters are placed on an offshore platform.
Claim 10
Dependent Claim
14 words
A method as described in claim 7 wherein acoustical emitters are placed on aircrafts.
Claim 11
Independent Claim
112 words
An apparatus for detecting and monitoring initiation and propagation of cracks in material comprising (a) an acoustical emitter adhered to the material in the area to be monitored, said emitter selected from the group consisting of brittle plastics, glass rods and strips, fiberglass, cadmium metal, tin metal, micarta, boron/epoxy reinforced strips, boron/aluminum reinforced strips, graphite/epoxy laminates and silicon carbide fiber laminates, (b) a monitor for detecting acoustical signals emitted by the adhered material when cracks in the monitored material initiate or propagate into the acoustical emitter, and (c) a series of transducers placed so as to detect emissions made by the acoustical emitter, said transducer being connected to (d) a monitoring system.
Claim 12
Independent Claim
112 words
An apparatus for detecting and monitoring initiation and propagation of cracks in material comprising (a) an acoustical emitter adhered to the material in the area to be monitored, said emitter selected from the group consisting of brittle plastics, glass rods and strips, fiberglass, cadmium metal, tin metal, micarta, boron/epoxy reinforced strips, boron/aluminum reinforced strips, graphite/epoxy laminates and silicon carbide fiber laminates, (b) a monitor for detecting acoustical signals emitted by the adhered material when cracks in the monitored material initiate or propagate into the acoustical emitter, and (c) a series of transducers placed so as to detect emissions made by the acoustical emitter, said transducer being connected to (d) a monitoring system.
Claim 13
Dependent Claim
12 words
An apparatus as described in claim 10 when used on non-porous materials.
Claim 14
Dependent Claim
12 words
An apparatus as described in claim 11 when used on structural materials.
Claim 15
Dependent Claim
12 words
An apparatus as described in claim 10 when used on porous materials.
Claim 16
Dependent Claim
32 words
An apparatus as described in claim 10 wherein the acoustical emitter is adhered to the material to be monitored with epoxy resins, silicone based adhesives, cyanoacrylate based adhesives, brazing, soldering and welding.
Claim 17
Dependent Claim
19 words
An apparatus as described in claim 14 wherein a plurality of acoustical emitters are placed on the material monitored.
Claim 18
Dependent Claim
31 words
An apparatus as described in claim 15 wherein a common monitoring system which is connected to transducers and is capable of locating the emitter actuated to detect acoustical emissions is used.
References Cited (Backward Citations)
US3774443A
Cited
US4009463A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-11-02 | 1985-05-04 | 1985-11-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-02 | 1989-05-04 | 1989-11-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-02 | 1993-05-04 | 1993-11-03 | $7700.00 | Window Closed / Lapsed |