Continuum approach for modeling fatigue in amorphous glassy polymers. Applications to the investigation of damage mechanisms in polycarbonate

In this study, we attempt to elucidate how the various micro-mechanisms con-
tribute to the fatigue development in an amorphous glassy matrix. To investi-
gate this issue, we propose an approach suitable for modeling fatigue in amor-
phous polymers. The studies are based on finite element analyses of a dogbone-shaped test specimen featuring plastic instabilities and localization behavior.
Also discussed is the development of fatigue damage in toughened polymers, in
view of dispersed particles. The results show that the fatigue damage initiates
at the sites following closely the localization of the plastic deformations or in-
stabilities, while the concentrated regions of hydrostatic stress were essentially
different. The more rigid the inclusions are, the more intensive the damage
growth in the ligaments between the inclusions, while the rigidity has no im-
pact on the location of the matrix damage. On the basis of the results, the
micro-mechanism which will trigger fatigue damage is discussed.