The proper mounting and using of strain gauges requires several distinct stages or steps, in which the installer must first clean and polish the surface properly. The strain gauge is then mounted and installed before connecting the lead wires (Yang & Lu 8580). Further, the installer also applies a protective coating in order to protect the strain gauge. The strain gauge device is essentially used for measuring strain on a specific object, with the most common form of this device comprising of a metallic foil pattern supported by a flexible and insulating backing.
This gauge is further fastened to the relevant object using cyanoacrylate or another suitable adhesive. In this case, deformation of the object causes the foil to also become deformed, thus leading to changes in the latter’s electrical resistance. The change in resistance, which is normally measured through the use of a Wheatstone bridge, and the strain on the object are related by the gauge factor quantity (Yang & Lu 8580).
Essentially, the strain gauge uses electrical conductance as a physical property in its operation and also relies on the geometry of the conductor. Stretching the electrical conductor within its elastic limit without deforming it permanently or breaking it causes it to become longer and narrower, which in turn leads to a decline in the conductor’s end-to-end electrical resistance (Kamnik et al. 41). In contrast, compression of the conductor without buckling causes it to shorten and broaden, which in turn decreases the conductor’s end-to-end electrical resistance.
By measuring the strain gauge’ electrical resistance, it is possible to infer the amount of stress induced. The strain gauge typically arranges thin and long conductive strips in a parallel line of zigzag patterns, ensuring that stress applied in the direction in which the parallel lines are oriented leads to larger multiple measurements of strain over the conductor surface’s effective length (Kamnik et al. 41). This causes increased resistance changes compared to the use of a single conductive wire in a straight line.
- Kamnik, Rok, Boštjan Kovačič, Andrej Štrukelj, Nikolay Vatin, and Vera Murgul. Applied Mechanics and Materials. Zurich: Trans Tech Publications, 2015. Print.
- Yang, Shixuan, and Nanshu Lu. “Gauge factor and stretchability of silicon-on-polymer strain gauges.” Sensors 13.7 (2013): 8577-8594. Print.
