# Stretch ratio

## Description

The stretch ratio or extension ratio is a measure of the extensional or normal strain of a differential line element, which can be defined at either the undeformed configuration or the deformed configuration. It is defined as the ratio between the final length ℓ and the initial length L of the material line

Related formulas## Variables

λ | Stretch ratio (dimensionless) |

l | Final length (m) |

L | Initial length (m) |