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US3636437A
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Methods for magnetically measuring stress using the linear relationship of the third harmonic to stress
Assignee: Individual
•
Filing: 1970-08-25
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Granted: 1972-01-18
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Expires: 1990-08-25
Abstract
Abstract A method for determining applied stress, yield stress and residual stress in a magnetic material. The method utilizes the amplitude of an induced third harmonic signal as an indication of the stress. Two measurements of the third harmonic amplitude are made, one for an unstressed and a second for a stressed condition. The amplitude indicative of the stress in the material is compared to the initial third harmonic reading according to a linear relationship to determine the stress.
Inventors
- 👤 Herman A Soulant Jr
- 👤 Henry C Brisker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 09:39
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/72; G01L; G01L1/00; G01L1/12; G01L1/125; G01L1/127; Y; Y10; Y10S; Y10S73/00; Y10S73/02
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
116 words
A method for measuring stress within a magnetic material comprising the steps of: inducing a cyclically varying magnetic flux field within a magnetic material; inducing a signal in a transducer placed with the magnetic flux field; filtering the transducer signal for the third harmonic of the cyclically varying field; detecting the third harmonic signal when zero stress is applied to the magnetic material; detecting the third harmonic signal when an unknown stress is applied to the magnetic material; and processing the signals of the third harmonic amplitude at zero stress and at the unknown stress in accordance with a linear relationship existing between the third harmonic amplitude and the stress to derive the unknown stress value.
Claim 2
Independent Claim
116 words
A method for measuring stress within a magnetic material comprising the steps of: inducing a cyclically varying magnetic flux field within a magnetic material; inducing a signal in a transducer placed with the magnetic flux field; filtering the transducer signal for the third harmonic of the cyclically varying field; detecting the third harmonic signal when zero stress is applied to the magnetic material; detecting the third harmonic signal when an unknown stress is applied to the magnetic material; and processing the signals of the third harmonic amplitude at zero stress and at the unknown stress in accordance with a linear relationship existing between the third harmonic amplitude and the stress to derive the unknown stress value.
Claim 3
Dependent Claim
44 words
The method of claim 1 wherein the linear relationship is: where Sy is the yield stress of the material, eo is the third harmonic amplitude at zero stress, ex is a third harmonic amplitude at the unknown stress, and Sx is the unknown stress.
Claim 4
Dependent Claim
41 words
The method of claim 1 wherein the linear relationship is: where Sy is the yield stress, eo is the third harmonic amplitude at zero stress, ex is the third harmonic amplitude at the unknown stress and Sx is the unknown stress.
Claim 5
Independent Claim
139 words
A method for measuring remnant stress within a magnetic material comprising the steps of: inducing a cyclically varying magnetic flux within a magnetic material; inducing a signal in a transducer placed within the magnetic flux field; filtering the transducer signal for the third harmonic of the cyclically varying flux field; detecting the third harmonic signal when the material is subject to the remnant stress; subjecting the magnetic material to a known incremental stress; detecting the third harmonic signal when the material is subjected to the known incremental stress; and processing the third harmonic signals produced at remnant stress, the third harmonic signal produced when a known incremental stress is applied to the material and the value of the yield stress, according to a linear relationship existing between stress and third harmonic amplitude to derive the value of remnant stress.
Claim 6
Independent Claim
139 words
A method for measuring remnant stress within a magnetic material comprising the steps of: inducing a cyclically varying magnetic flux within a magnetic material; inducing a signal in a transducer placed within the magnetic flux field; filtering the transducer signal for the third harmonic of the cyclically varying flux field; detecting the third harmonic signal when the material is subject to the remnant stress; subjecting the magnetic material to a known incremental stress; detecting the third harmonic signal when the material is subjected to the known incremental stress; and processing the third harmonic signals produced at remnant stress, the third harmonic signal produced when a known incremental stress is applied to the material and the value of the yield stress, according to a linear relationship existing between stress and third harmonic amplitude to derive the value of remnant stress.
Claim 7
Dependent Claim
53 words
A Method of claim 4 wherein the linear relationship is: where Sy is the yield stress, eo is the initial third harmonic voltage where the material is subjected to remnant stress, Si is the known incremental stress, ei is the third harmonic amplitude produced when the material is subjected to the incremental stress.
Claim 8
Dependent Claim
49 words
The method of claim 4 wherein the linear relationship is: where Sy is the yield stress, eo is the third harmonic amplitude produced by the remnant stress, ei is the third harmonic amplitude produced when the material is subjected to an incremental stress, and Si is the incremental stress.
Claim 9
Dependent Claim
16 words
The method of claim 2 wherein the relationship between stress and third harmonic amplitude is positive.
Claim 10
Dependent Claim
17 words
The method of claim 3 wherein the relationship between the third harmonic amplitude and stress is negative.
Claim 11
Dependent Claim
16 words
The method of claim 5 wherein the relationship between stress and the third harmonic is negative.
Claim 12
Dependent Claim
17 words
The method of claim 6 wherein the relationship between the third harmonic amplitude and stress is negative.
Claim 13
Independent Claim
116 words
A method for measuring yield stress within a magnetic material comprising the steps of: inducing a cyclically varying magnetic flux field within a magnetic material; inducing a signal in a transducer placed within the field; filtering the signal for the third harmonic of the cyclically varying field; detecting the third harmonic signal when zero stress is applied to the magnetic material; detecting the third harmonic signal when a known incremental stress is applied to the magnetic material; and processing the signals recorded of the third harmonic amplitude at zero stress and at the known stress in accordance with the linear relationship existing between the third harmonic amplitude and the stress to derive the yield stress value.
Claim 14
Independent Claim
116 words
A method for measuring yield stress within a magnetic material comprising the steps of: inducing a cyclically varying magnetic flux field within a magnetic material; inducing a signal in a transducer placed within the field; filtering the signal for the third harmonic of the cyclically varying field; detecting the third harmonic signal when zero stress is applied to the magnetic material; detecting the third harmonic signal when a known incremental stress is applied to the magnetic material; and processing the signals recorded of the third harmonic amplitude at zero stress and at the known stress in accordance with the linear relationship existing between the third harmonic amplitude and the stress to derive the yield stress value.
Claim 15
Dependent Claim
46 words
The method of claim 11 wherein the linear relationship is: where Sy is the yield stress, eo is the third harmonic amplitude at zero stress, ei is the third harmonic amplitude when the material is subjected to the incremental stress; and Si is the incremental stress.
Claim 16
Dependent Claim
46 words
The method of claim 11 wherein the linear relationship is: where Sy is the yield stress, eo is the third harmonic amplitude at zero stress, ei is the third harmonic amplitude when the material is subjected the yield incremental stress, and Si is the incremental stress.
Claim 17
Dependent Claim
17 words
The method of claim 12 wherein the relationship between the third harmonic amplitude and stress is positive.
Claim 18
Dependent Claim
17 words
The method of claim 13 wherein the relationship between the stress and the third harmonic is negative.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-17 | 1975-07-19 | 1976-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-17 | 1979-07-19 | 1980-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-17 | 1983-07-19 | 1984-01-18 | $7700.00 | Window Closed / Lapsed |