The criterion is very similar to maximum stress criterion, except that it is calculated from the mechanical (or equivalent) strain tensor components. The failure index is calculated as follows:
in which the and allowables depend on the sign of and respectively. Ply or laminate passes the test if the three following conditions are satisfied:
The reserve factor is calculated as follows:
and the strength ratio is given by:
This criterion is referred to as “MaxStrain” criterion in FeResPost.
FeResPost proposes a second version of the criterion where the “total” strain tensor is used instead of the mechanical strain tensor . This version of the criterion is referred to as “MaxTotalStrain” criterion in FeResPost.