The elements of the strain tensor are dimensionless (displacements divided by distances).

Similarly, the symmetry of the infinitesimal strain tensor implies that .

The Green-Lagrangian strain tensor is a measure of how much differs from .

If sufficient measurements are made in different directions it is possible to derive the strain tensor.

It is closely related to the strain tensor defined earlier.

Hence the expression above becomes where is the rate of strain tensor.

It is the constraints on the strain tensor that are most easily understood.

Similarly, there are at most 6 different elements of the strain tensor .

The transformation for the strain tensor has a slightly different form because of the choice of notation.

Fig. 6.10 (more formally, they are approximately along the positive principal axis of the mean flow rate of strain tensor).