On the definitions of strain and their use in large-strain analysis

It is pointed out that when strains are computed from a displacement field, the engineering definition of strain(lf−li)/li has advantages in respect to other definitions used in finite-strain theory. Tensorial transformations can still be used easily by means of Mohr's circle. Illustrations for the case of Eulerian and Lagrangian strains are shown. The comments may be of particular interest to experimental analysts.