Definition(s)
Logarithmic Strain
Dimensionless measure of the stretch of a deforming line element, defined as the natural logarithm of the ratio of the current length of the line element to its original length 1
NOTE Alternatively, the logarithmic strain can be estimated as the natural logarithm of one plus the engineering strain.
Source: API TR 5C3, Technical Report on Equations and Calculations for Casing, Tubing, and Line Pipe Used as Casing or Tubing; and Performance Properties Tables for Casing and Tubing, Upstream Segment, First Edition, December 2008. Global Standards