Compensated high temperature strain gage

US5375474A · kind A · utility

Assignee

• The United States of America as represented by the United States National Aeronautics and Space Administration · US

Inventor

• Thomas C. Moore · Livermore, US

Key dates

• Filing date: Aug 12, 1992
• Grant date: Dec 27, 1994
• Expiry date: Aug 12, 2012

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T29/49103
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A device for measuring strain in substrates at high temperatures in which the thermally induced apparent strain is nulled. Two gages are used, one active gage and one compensating gage. Both gages are placed on the substrate to be gaged; the active gage is attached such that it responds to mechanical and thermally induced apparent strain while the compensating gage is attached such that it does not respond to mechanical strain and measures only thermally induced apparent strain. A thermal blanket is placed over the two gages to maintain the gages at the same temperature. The two gages are wired as adjacent arms of a Wheatstone bridge which nulls the thermally induced apparent strain giving a true reading of the mechanical strain in the substrate.