  The mechanical problem discussed in this paper focuses on the stress state
estimation in a composite laminate in the vicinity of a free edge or
microcracks. To calculate these stresses, we use two models called
Multiparticle Models of Multilayered Materials (M4). The first one can be
considered as a stacking sequence of Reissner-Mindlin plates (5 kinematic
fields per layer), while the second is a membranar superposition (2 fields per
layer plus a global one). These simplified models are able to provide finite
values of interfacial stresses, even on the free edges of a structure. The
current paper consists of validating the M4 by a finite element analysis
through describing the stress fields in both a (0,90)s laminate in tension
(free-edge problem) and a transversally microcracked (0,90)s laminate. A
comparison of the various energy contributions helps yield a mechanical
perspective: it appears possible to define an interply energy as well as a
layer energy, these energies expressing the FE 3D reality.
