Strain gauge

What is a strain gauge?

Strain gauges are metallic-electric measuring elements that precisely measure forces, loads, torque, etc., particularly in static processes. Strain gauges operate based on the physical effect by which the electrical resistance of a wire changes proportionally to the strain exerted on the wire when stretched or compressed. Strain gauges are used in sensors, force and torque sensors, load sensors (for scales), and other measuring devices. Strain gauges are frequently affixed to measuring bodies made of high-strength material.

How are strain gauges used?

The strain gauge was invented in 1938, the year in which Edward E. Simmons and Arthur C. Ruge, each working independently, took decisive steps to develop the strain gauge. Today, instead of a wire, the measuring grid is made of an extremely thin metallic foil (≈ 0.005 mm) on which a zig-zag pattern is etched. This results in strain gauges with extremely small dimensions (e.g., with measuring grids of 1 × 1 mm) for quasi point-like measurements.

What are the advantages of strain gauges?

  • Tensile and compression measurement without pretension
  • Suitable for long-term static measurements
  • Easy data analysis thanks to absolute measured value acquisition
  • Compensation of temperature fluctuations by means of a Wheatstone bridge

Kistler uses the strain gauge principle primarily for measuring torque on rotating shafts and in certain force sensors. Check out the difference between piezo and strain gauge.

Strain gauge (DMS) scheme
Strain gauges are metallic-electrical measuring elements that precisely measure forces, loads, torques, etc., especially in the static range. The wire used changes its electrical resistance during stretching or compression proportionally to its elongation.