logarithmic strain

Conversions of strain ratios to stretches at a given volume change can be plotted directly onto a logarithmic strain plot (see screen shot ).

High degrees of wire drawing (logarithmic strain above 3) leads to pearlitic wires with yield strengths of several Giga Pascals.

The logarithmic strain ε, also called, true strain or Hencky strain (although nothing particularly "true" about it compared to other valid valid definitions of strain).

The logarithmic strain provides the correct measure of the final strain when deformation takes place in a series of increments, taking into account the influence of the strain path.

On the other hand, for some materials, e.g. elastomers and polymers, subjected to large deformations, the engineering definition of strain is not applicable, e.g. typical engineering strains greater than 1%, thus other more complex definitions of strain are required, such as stretch, logarithmic strain, Green strain, and Almansi strain.