US4572001A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for measuring thermodynamic response
Assignee: Queen's University
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Filing: 1984-01-30
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Granted: 1986-02-25
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Expires: 2004-01-30
Abstract
Abstract A method and apparatus for precisely controlling plastic strain rate during plastic deformation testing of a solid material such as a metal or plastic are described in which the effects of elastic strain rates associated with the specimens and machines used for such testing are eliminated by applying corrections proportional to the load on the specimen. Thus strain rate sensitivity, unaffected by the machine or specimen modulus can be measured. Strain rate sensitivity can be used to measure the activation volume of the specimen which may be used for quality control of material processing and/or manufactured articles.
Inventors
- 👤 Shigeo Saimoto
- 👤 Zbigniew Basinski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 08:27
CPC Classifications
G; G01; G01N; G01N3/00; G01N3/08
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
135 words
A method for precisely controlling plastic strain rate change during plastic deformation testing of a solid material specimen, comprising the steps of: (a) applying plastic strain to said specimen, mounted in a testing frame, at a predetermined controlled displacement rate; (b) applying an abrupt plastic strain rate change at one or more predetermined strain increments; (c) measuring the imposed plastic strain rate change; (d) detecting any net change in elastic response of said testing frame, including said specimen, during testing; (e) applying an elastic compensating displacement to said testing frame, including said specimen, so that the actual plastic strain rate response of the deforming specimen can be measured; and (f) measuring any incremental change of stress required for continuous plastic flow of the specimen upon application of said abrupt change in the plastic strain rate.
Claim 2
Independent Claim
135 words
A method for precisely controlling plastic strain rate change during plastic deformation testing of a solid material specimen, comprising the steps of: (a) applying plastic strain to said specimen, mounted in a testing frame, at a predetermined controlled displacement rate; (b) applying an abrupt plastic strain rate change at one or more predetermined strain increments; (c) measuring the imposed plastic strain rate change; (d) detecting any net change in elastic response of said testing frame, including said specimen, during testing; (e) applying an elastic compensating displacement to said testing frame, including said specimen, so that the actual plastic strain rate response of the deforming specimen can be measured; and (f) measuring any incremental change of stress required for continuous plastic flow of the specimen upon application of said abrupt change in the plastic strain rate.
Claim 3
Dependent Claim
18 words
A method as claimed in claim 1 wherein said solid material is selected from metallic and thermoplastics materials.
Claim 4
Dependent Claim
29 words
A method as claimed in claim 1 wherein said corrections are effected by means of a command module associated with an electrohydraulic testing machine controlled by a servo system.
Claim 5
Independent Claim
167 words
An apparatus for precisely controlling plastic strain rate change during plastic deformation testing of a solid material specimen, comprising: (a) frame means; (b) specimen mounting means for mounting a specimen in said frame meeans for said testing therein; (c) plastic strain applying means for applying a plastic strain to said specimen in said frame at a selected controlled displacement rate; (d) strain rate change means for applying an abrupt plastic strain rate change at a predetermined strain increment; (e) first measurement means for measuring said imposed plastic strain rate change; (f) detection means for detecting any net change in elastic response of said frame means, including said specimen, during testing; (g) compensation means for precisely compensating for said net change in elastic response so that the actual plastic strain rate response of said non-elastic deforming specimen can be measured; and (h) second measurement means for measuring any incremental change of stress required for continuous plastic deformation of said specimen upon abrupt change in the plastic strain rate.
Claim 6
Independent Claim
167 words
An apparatus for precisely controlling plastic strain rate change during plastic deformation testing of a solid material specimen, comprising: (a) frame means; (b) specimen mounting means for mounting a specimen in said frame meeans for said testing therein; (c) plastic strain applying means for applying a plastic strain to said specimen in said frame at a selected controlled displacement rate; (d) strain rate change means for applying an abrupt plastic strain rate change at a predetermined strain increment; (e) first measurement means for measuring said imposed plastic strain rate change; (f) detection means for detecting any net change in elastic response of said frame means, including said specimen, during testing; (g) compensation means for precisely compensating for said net change in elastic response so that the actual plastic strain rate response of said non-elastic deforming specimen can be measured; and (h) second measurement means for measuring any incremental change of stress required for continuous plastic deformation of said specimen upon abrupt change in the plastic strain rate.
Claim 7
Dependent Claim
21 words
Apparatus as claimed in claim 4 wherein said strain rate is effected by an electro-hydraulic system controlled by a servo system.
Claim 8
Dependent Claim
16 words
Apparatus as claimed in claim 5 wherein said electro-hydraulic system includes analog or digital command control.
Claim 9
Dependent Claim
16 words
Apparatus as claimed in claim 6 wherein said control is digital and amenable to computer control.
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) | 1989-02-24 | 1989-08-26 | 1990-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-24 | 1993-08-26 | 1994-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-24 | 1997-08-26 | 1998-02-25 | $7700.00 | Window Closed / Lapsed |