Strain Calculator
Calculate engineering strain from the change in length and original length of a member.
Engineering Strain
0.001000 mm/mm
Engineering Strain vs Change in Length
Formule
## Engineering Strain Strain measures the deformation of a body relative to its original size. ### Formula **epsilon = delta_L / L_0** where delta_L is the change in length and L_0 is the original gauge length. Strain is dimensionless but is often expressed in microstrain (x 10^6) or as a percentage. Tensile strain is positive; compressive strain is negative.
Exemple Résolu
A 500 mm gauge length bar elongates by 0.5 mm under load.
- 01epsilon = 0.5 / 500 = 0.001 mm/mm
- 02As percentage: 0.001 x 100 = 0.1%
- 03In microstrain: 0.001 x 10^6 = 1000 microstrain
Questions Fréquentes
What is the difference between engineering and true strain?
Engineering strain uses the original length as reference. True strain uses the instantaneous length: epsilon_true = ln(1 + epsilon_eng). They differ significantly only at large deformations (above about 5%).
What is a typical yield strain for steel?
For structural steel with 250 MPa yield and 200 GPa modulus, yield strain is 250/200000 = 0.00125 or 1250 microstrain.
How is strain related to stress?
In the elastic range, stress = E x strain (Hooke's law). Beyond the elastic limit, the relationship becomes nonlinear and material-specific.
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