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Bonded Wire Strain Gauge on Paper: Simmons, 1942

Edward E. Simmons, Jr. · Public domain (expired patent)

أنشأه

Penny

13. أكتوبر 2026

Bonded Wire Strain Gauge on Paper: Simmons, 1942

Edward E. Simmons, Jr. of Pasadena patented the bonded wire strain gauge in 1942, US 2,292,549 (filed 1940). A very fine resistance wire is cemented to a member along its entire length, so it stretches and shortens exactly with the surface and its electrical resistance follows the strain. His preferred form: Constantan or Advance wire, about 0.003 inch, wound back and forth on a thin paper, set in Glyptal, then cemented to the member and calibrated.

متقدم

Workshop process

التعليمات

Wind the filament on thin paper

Use a fine resistance wire such as Constantan or Advance (a copper-nickel alloy, about 45 % nickel and 55 % copper); Simmons used No. 40 gauge, about 0.0031 inch. Wind it back and forth across a thin paper in parallel lengths whose alternate ends are joined, the strands very close together but not touching. A winding jig keeps the filament slightly taut.

المواد لهذه الخطوة:

سلك كونستانتان1 as required

ورق1 ورقة

الأدوات المطلوبة:

قالب لف الأسلاك

مقص

Set it in Glyptal

Cover the wound filament with Glyptal and let it dry and harden thoroughly. Filament and paper now form one gauge unit, the filament lying in the plane of the paper surface.

المواد لهذه الخطوة:

راتنج ألكيد غليبتال1 as required

الأدوات المطلوبة:

فُرَش دقيقة

فرن تجفيف

Cement it to the member

Put Glyptal on the surface of the member and wrap the gauge unit on with the strands running in the direction of the strain to be measured, the paper outside. The small amount of Glyptal on the surface insulates the filament from the member. Hold filament and paper in place by wrapping them with thread, then dry and harden the Glyptal thoroughly.

المواد لهذه الخطوة:

راتنج ألكيد غليبتال1 as required

خيط قطني1 as required

الأدوات المطلوبة:

فُرَش دقيقة

فرن تجفيف

مقص

Calibrate it

Load the member progressively in a materials testing machine and note the change in the filament's resistance at each load, measured on a Wheatstone bridge in which the filament is one arm. For very fast loads, as in impact tests, an oscillograph takes the place of the galvanometer.

الأدوات المطلوبة: