Micro-mechanical modeling of fibrillation in amorphous polymers

Multiple void growth in amorphous polymers and the subsequent deformation of the surrounding matrix material into fibrils is investigated using continuum micro-mechanical models and finite element simulations. The polymer material is described by a constitutive model that particularly accounts for the progressive hardening due to stretching of the molecular network. Two different criteria for local failure are employed in the modeling of void coalescence. Numerical simulations are performed considering periodic and random arrangements of initial voids under tensile loading. Effects of various parameters on the overall response of the damaging material are analyzed.