Definition
Small sensors bonded to a structural part that change their electrical resistance as the part stretches or compresses under load. By measuring the change in resistance, technicians and engineers can calculate how much the material is being deformed, and from that, how much force or stress is acting on it.
Plain English
Tiny stick-on sensors that detect how much a piece of metal or other material is being stretched or squeezed. They turn that stretching into an electrical signal that can be read on a meter or instrument.
Context Anchor
Seen in aircraft maintenance, structural testing, and load-measuring equipment where a force, weight, or bending movement must be turned into a measurable electrical reading.
Derivation
Strain in engineering means the amount a material is stretched or compressed compared to its original length. Gauge means a measuring device. So a strain gauge is literally a device that measures stretch.
Why Pilots Care
If strain gauges or their wiring are damaged, a system that depends on them may give an incorrect load, force, or weight reading, which can affect maintenance decisions and aircraft safety.
Intuition Check
Do not think of a strain gauge as a cockpit dial. Here, “gauge” means a sensor that measures tiny shape changes, not necessarily an instrument with a needle or display.
Example Sentence 1
Strain gauges bonded to the wing spar allowed engineers to record how much the structure flexed during the load test.
Example Sentence 2
The readings from the strain gauges showed the fuselage skin was deforming within limits.