“…In order to describe the porosity of a Cosserat shell with voids, we consider two independent scalar fields m(h a , t) and v(h a , t) called the volume fraction fields (0 < m 6 1). We mention that, in the previous approaches of the theory of Cosserat shells with voids (see Bîrsan, 2000aBîrsan, , 2005, only one porosity field has been admitted, corresponding to m(h a , t), which permits for the characterization of the changes in volume fraction along the middle surface of the three-dimensional shell. In this paper, we introduce an additional porosity field, namely v(h a , t), which will give us information about the volume fraction variations along the shell thickness.…”