truestrain

Truestrain is a term used in materials science and continuum mechanics to denote true strain, a logarithmic measure of deformation. It is defined as ε_true = ln(L/L0), where L is the current length of a material segment and L0 is its original length. Truestrain accounts for continuous length changes during deformation, making it more accurate than some alternatives for large strains.

In practice, true strain is related to engineering strain by ε_true = ln(1 + ε_eng). For small deformations, ε_true approximates ε_eng, and the two measures converge as strains diminish. True strain is preferred in analyses involving large plastic or elastic deformations because it remains valid across evolving geometry.

Applications of truestrain include metal forming analysis, high-precision stress–strain measurements, and constitutive modeling in finite-strain plasticity and hyperelastic material descriptions. It provides a consistent deformation metric in simulations where geometry changes significantly, such as extrusion, stamping, or compressive forming, and it underpins calibration of material models across varying strains.

Terminology and usage notes: the compound form "truestrain" is sometimes encountered in software variable names, informal discussions, or places where a space is impractical, serving as a shorthand for true strain. The standard terminology in scholarly work is "true strain" or "logarithmic strain." The concept is also sometimes referred to as logarithmic strain in the literature.

See also: engineering strain, logarithmic strain, true strain, finite strain, material science.