The forces and movements at all contact planes are used to obtain the macroscopic stress
and strain tensors (Figure 7).
It was assumed that incipient microcracks appear in the planes with orientation close to the basic area corresponding to the principal macroscopic stress
the viscoelastic stage, characterized by a homogeneous macroscopic stress.
32), substantial cavitation in polymer leads to a weakening effect characterized by a lower macroscopic stress supported by the tensile specimen.
The macroscopic stress and the lattice constant can be calculated from lattice plane distances d (17) by using equations (2) and (3).
The experimental (hkl) data from the five TiN reflections were linearly fitted to equation (3) and resulted in a macroscopic stress [alpha] = -1.
43 into 42, the relationship between the average reduced stress and the macroscopic stress
can be expressed as
The description of the viscoplastic behavior is based on the splitting of the macroscopic stress (28) into thermal and athermal back stresses (associated with incompatibilities of deformation caused by the behavior of crystalline and amorphous phases), and thermal and athermal effective stresses (associated with shortrange interactions).
The relaxation of macroscopic stress can be associated with the relaxation of the stress in the amorphous phase of the polymer whose macromolecules are "free" to move at room temperature.
The macroscopic stress
was spilt into an effective stress and a back stress so that the interactions between crystalline lamellae and amorphous phases could be taken into account.
13) since we show that the large initial void volume fraction and the growth of voids decrease the macroscopic stress
(or relieve the plane strain constraint) ahead of the tip, with the assumption that cavitation occurs early in the deformation.
a] = [Gamma]), and ii) that the macroscopic stress
follows the two-phase parallel composite approach of Voigt: