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US4155264A Expired / Lapsed US ⏱️ 0.0 years remaining

Method of determining internal stresses in structural members

Assignee: Kraftwerk Union AG
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Filing: 1978-05-16
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Granted: 1979-05-22
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Expires: 1998-05-16
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Abstract

Abstract Method for determining internal stresses in structural members in machine or apparatus manufacturing by machining, around a measuring location provided with strain gages, a circular slot into the surface of the structural member that is to be measured, measuring changes in strain of the core of the measuring location left standing, and calculating the internal stresses from the measured strains and a depth-dependent decay function determined on a calibrating material sample, the improvement therein affording the determination of internal stresses in the structural members at depths greater than about 5 mm, includes the steps of mechanically removing the measuring-location core down to a new surface at the base of the circular slot, securing a strain gage to a new measuring location at the new surface, machining another circular slot around the new measuring location, measuring changes in strain of the core of the new measuring location left standing while measuring changes in strain thereof and repeating the foregoing steps for respective slot depths until a given depth at which internal stresses in the structural members are to be determined is reached, a separate depth-dependent decay function being determined on a calibrating material sample for each new measuring location core.

Inventors

  • 👤 Norbert Bender
  • 👤 Gerhard Hofer
  • 👤 Olaf Lenz
  • 👤 Erwin Stucker

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-02 21:34
CPC Classifications
G; G01; G01L; G01L5/00; G01L5/0047

Claims Analysis

Total Claims: 2
Claim 1
Independent Claim 200 words
Method for determining internal stresses in structural members in machine or apparatus manufacturing by machining, around a measuring location provided with strain gages, a circular slot into the surface of the structural member that is to be measured, measuring changes in strain of the core of the measuring location left standing, and calculating the internal stresses from the measured strains and a depth-dependent decay function determined on a calibrating material sample, the improvement therein affording the determination of internal stresses in the structural members at depths greater than about 5 mm, which comprises the steps of mechanically removing the measuring-location core down to a new surface at the base of the circular slot, securing a strain gage to a new measuring location at the new surface, machining another circular slot around the new measuring location, measuring changes in strain of the core of the new measuring location left standing while measuring changes in strain thereof and repeating the foregoing steps for respective slot depths until a given depth at which internal stresses in the structural members are to be determined is reached, a separate depth-dependent decay function being determined on a calibrating material sample for each new measuring location core.
Claim 2
Dependent Claim 200 words
Method for determining internal stresses in structural members in machine or apparatus manufacturing by machining, around a measuring location provided with strain gages, a circular slot into the surface of the structural member that is to be measured, measuring changes in strain of the core of the measuring location left standing, and calculating the internal stresses from the measured strains and a depth-dependent decay function determined on a calibrating material sample, the improvement therein affording the determination of internal stresses in the structural members at depths greater than about 5 mm, which comprises the steps of mechanically removing the measuring-location core down to a new surface at the base of the circular slot, securing a strain gage to a new measuring location at the new surface, machining another circular slot around the new measuring location, measuring changes in strain of the core of the new measuring location left standing while measuring changes in strain thereof and repeating the foregoing steps for respective slot depths until a given depth at which internal stresses in the structural members are to be determined is reached, a separate depth-dependent decay function being determined on a calibrating material sample for each new measuring location core.

References Cited (Backward Citations)

US3765230A Cited
US3803905A Cited
US3943758A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1982-05-21 1982-11-20 1983-05-22 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1986-05-21 1986-11-20 1987-05-22 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1990-05-21 1990-11-20 1991-05-22 $7700.00 Window Closed / Lapsed

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