High Temperature Capacitive Strain Gage

Wnuk, Stephen P., Jr.; Wnuk, Stephen P., III; Wnuk, V. P.

Capacitive strain gages designed for measurements in wind tunnels to 2000 F were built and evaluated. Two design approaches were followed. One approach was based on fixed capacitor plates with a movable ground plane inserted between the plates to effect differential capacitive output with strain. The second approach was based on movable capacitor plates suspended between sapphire bearings, housed in a rugged body, and arranged to operate as a differential capacitor. A sapphire bearing gage (1/4 in. diameter x 1 in. in size) was built with a range of 50,000 and a resolution of 200 microstrain. Apparent strain on Rene' 41 was less than + or - 1000 microstrain from room temperature to 2000 F. Three gage models were built from the Ground Plane Differential concept. The first was 1/4 in. square by 1/32 in. high and useable to 700 F. The second was 1/2 in. square by 1/16 in. high and useable to 1440 F. The third, also 1/2 in. square by 1/16 in. high was expected to operate in the 1600 to 2000 F range, but was not tested because time and funding ended.

Document ID

19900004444

Acquisition Source

Legacy CDMS

Document Type

Contractor Report (CR)

Authors

Date Acquired

September 6, 2013

Publication Date

January 1, 1990

Publication Information

Publisher: NASA

Subject Category

Report/Patent Number

Accession Number

90N13760

Funding Number(s)

Distribution Limits

Public

Work of the US Gov. Public Use Permitted.

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