strain tensor

A 3D strain tensor
$\tag{1} \mathbf{\varepsilon} = \left[ \begin{array}{ccc} \varepsilon _{xx} & \varepsilon _{xy} & \varepsilon _{xz} \newline \varepsilon _{yx} & \varepsilon _{yy} & \varepsilon _{yz} \newline \varepsilon _{zx} & \varepsilon _{zy} & \varepsilon _{zz} \newline \end{array} \right],$
where
- $\varepsilon _{ab}$ ( $a = b$ ) for normal strain,
- $\varepsilon _{ab}$ ( $a \ne b$ ) for shear strain.

Dragana Jandric, "Mechanical Strain in Deformation Analysis – Lesson 4: Strain Tensor Defined", Ansys, 23 May 2020 (), url https://innovationspace.ansys.com/courses/wp-content/uploads/2020/05/Lesson-4-Strain-Tensor-Defined.pdf [20250131].