US4283956A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of detecting the onset of cracking in articles during dynamic testing
Assignee: MTU Aero Engines AG
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Filing: 1979-05-10
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Granted: 1981-08-18
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Expires: 1999-05-10
Abstract
Abstract A method is disclosed for detecting the onset of cracking in an article subjected to dynamic loading. The article is subjected to a dynamically changing load, and additionally is loaded and vibrated at its natural frequency. The onset of a crack in the article is determined by noting a change in its natural frequency.
Inventors
- 👤 Karl Lechner
- 👤 Erich Bosmiller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:21
CPC Classifications
G; G01; G01N; G01N3/00; G01N3/32; G01N29/00; G01N29/04; G01N29/12; G01N29/22; G01N29/227; G01N2203/00; G01N2203/003; G01N2203/0042; G01N2203/0048; G01N2203/0058; G01N2203/006; G01N2203/0062; G01N2203/0064; G01N2203/0069; G01N2203/0073; G01N2291/00; G01N2291/02; G01N2291/025; G01N2291/0258; G01N2291/028; G01N2291/02827
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
50 words
A method of detecting the onset of cracking in an article subjected to dynamic loading, including subjecting the article to a dynamically changing load, and additionally loading and vibrating the article at its natural frequency, and determining the onset of a crack by noting a change in the natural frequency.
Claim 2
Independent Claim
50 words
A method of detecting the onset of cracking in an article subjected to dynamic loading, including subjecting the article to a dynamically changing load, and additionally loading and vibrating the article at its natural frequency, and determining the onset of a crack by noting a change in the natural frequency.
Claim 3
Dependent Claim
18 words
A method as claimed in claim 1, wherein the natural frequency is always measured at the same load.
Claim 4
Dependent Claim
17 words
A method as claimed in claim 2, wherein the natural frequency is measured at zero test load.
Claim 5
Dependent Claim
34 words
A method as claimed in claim 1, 2 or 3, wherein the article is excited at its natural frequency by feeding this excitation frequency via the servo valve of a dynamic material testing machine.
Claim 6
Dependent Claim
24 words
A method as claimed in claim 4, wherein the article is excited at its natural frequency by means of an additional high-frequency servo valve.
Claim 7
Dependent Claim
37 words
A method as claimed in claim 1, 2 or 3, wherein the article is excited at its natural frequency by means of an electro-magnetic oscillator, which acts on a loading piston of a dynamic material testing machine.
Claim 8
Dependent Claim
36 words
A method as claimed in claim 6, wherein the article is excited at its natural frequency by means of an additional high-frequency servo valve, which superimposes the natural frequency of the test frequency of the piston.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-08-17 | 1985-02-16 | 1985-08-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-17 | 1989-02-16 | 1989-08-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-17 | 1993-02-16 | 1993-08-18 | $7700.00 | Window Closed / Lapsed |