Device for determining surface strains during the measurement of inherent stresses in structural components of machines or apparatus

US3943758A · kind A · utility

Assignee

• Kraftwerk Union Aktiengesellschaft · DE

Inventors

• Helmut Wolf · Holzkirchen, DE
• Wolfgang Bohm · Alzenau, DE
• Erwin Stucker

Key dates

• Filing date: Sep 9, 1974
• Grant date: Mar 16, 1976
• Expiry date: Sep 9, 1994

Classification

• Technology area (CPC G): Physics
• CPC primary: G01L1/2287
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Apparatus for checking a structural component for inherent stresses includes strain gage means for attachment to a surface measuring area of the component, the strain gage means having terminals for leads, means for cutting an annular groove into the component around the area, electrical response measuring means remote from the area, and leads extending from the terminals of the strain gage means to the electrical response measuring means for measuring the change in electrical response of the strain gage means due to the cutting of successive layers of material out of the groove, as indicative of the inherent stress existing prior thereto, the cutting means includes a crown boring tool for machining the annular groove around the measuring area, the crown boring tool having a shaft hollow throughout and being mounted in a hollow boring spindle, the terminal leads of the strain gage means attached to the measuring area extending through the crown boring tool and the hollow boring spindle. The apparatus further includes a base plate, the strain gage means being a plurality of strain gage strips mounted on the plate, each of the strips having two of the terminal leads, one of the termi…