Engineering Strain

Summary

Engineering Strain - Strain is a measure of the magnitude of a deformation caused by a stress. Engineering strain is a slightly simplified measure of true strain, used by engineers in their calculations.

Technical Information

The principal difference between engineering and true strain is:

True strain is calculated at each point throughout the experiment and considers the change in cross-section of the deformed body, in turn giving a more accurate result.

Engineering strain assumes a constant cross-section, giving slightly more inaccurate results but still acceptable for engineering applications.

Engineering strain is calculated as the change in length divided by the original length:

ε = ΔL/L0 where:
ε = engineering strain
ΔL = change in length
L0 = original length

Strain can also be given as the percentage increase in length compared to the material in its unstressed state.