# Examples of Strain-gage Measurement of Tensile/Compressive Stress

## Quarter-bridge System (1-gage System)

See the figure below. If a strain gage is bonded on a surface of a pillar which receives uniform load from one direction and the gage axis is aligned to the direction, stress σ is calculated by the following equation :

Stress (σ) = ε_{0} ・E

where, E : Young's modulus (See table "Mechanical Properties of Industrial Materials" at the left.)

ε_{0} : Indicated strain

And, the load W applied to the pillar is obtained by the following equation:

Load W = A・σ

where, A: Cross-sectional area of the pillar

## Half-bridge System (2-gage System)

If another strain gage is bonded to the pillar at a right angle to the loading direction and 2 gages are connected to adjacent legs of the bridge, the surface stress σ on the pillar is expressed by the following equation:

If another strain gage is bonded to the pillar at a right angle to the loading directions and 2 gages are connected to adjacent legs of the bridge, the surface stress σ on the pillar is expressed by the following equation: