# Shear Strain

## Definition - What does Shear Strain mean?

Shear strain is the ratio of deformation to original dimensions. In the case of shear strain, it is the amount of deformation perpendicular to a given line rather than parallel to it.

In engineering, shear strain is defined as the tangent of the angle, and is equal to the length of deformation at its maximum divided by the perpendicular length in the plane of force application, which sometimes makes it easier to calculate. Strains measure how much a given deformation differs locally from a rigid-body deformation.

## Corrosionpedia explains Shear Strain

Shear strain is the strain resulting from the application of opposing forces in a direction parallel to a surface or to a planar cross section of a body. It is an angular change at some point in a shape. When scissors cut paper, they cause the paper to undergo a shear strain so large that the paper yields, coming apart where it is strained.

Shear strain is related to shear modulus, which is a coefficient of elasticity of a substance, expressing the ratio between the force per unit area (shearing stress) that laterally deforms the substance and the shear (shearing strain) that is produced by this force.

A strain is a normalized measure of deformation representing the displacement between particles in the body relative to a reference length. Strains may be classified like stresses as normal strain and shear strain, acting perpendicular to or along the face of an element, respectively. The amount of distortion associated with the sliding of plane layers over each other is the shear strain within a deforming body. This could be applied by elongation, shortening, volume changes or angular distortion.

Normal strains produce dilations. If there is an increase in length of the material line, the normal strain is called tensile strain. Otherwise, if there is reduction or compression in the length of the material line, it is called compressive strain.

Normal strain measures changes in length along a specific direction. It is also called extensional strain as well as dimensional strain. Shear strain measures changes in angles with respect to two specific directions.