Strain

Strain

      Strain is the amount of deformation of a body due to an applied force; it is defined as the fractional change in dimension to original dimension.

                                                       

ε = ΔL/L  

  Strain can be Negative or Positive. Magnitude of Strain is very small and is hence usually expressed as microstrain.

Strain Gauge

       Strain Gauge is a device used to measure Strain. A strain gauge takes advantage of the physical property of electrical conductance and its dependence on the conductor's geometry. Resistance is depended on length and area of the material. The change in resistance of a device is reasonably linear function of its deformation, hence strain is measured by measuring the change in resistance due to deformation. 

Types of Strain Gauges

Depending upon the principle of operation Strain gauges are classified into

1. Mechanical Strain Gauge
2. Optical Strain Gauge
3. Electrical Strain Gauge

Mechanical Strain Gauge