Multiscale approach for fatigue simulation in thermoplastic polymers

Resumo

In mechanical engineering projects, mechanical fatigue is one of the most frequent sources of failure of
devices submitted to cyclic loads.This is the case of orthopedic implants and prostheses, many of which are made
of, or incorporate, polymeric materials. In large semi-crystalline polymers, mechanical fatigue is dominated by the
nucleation process as a consequence of localized inelastic strain accumulation and craze formation. To simulate the
local nucleation phenomenon in polymers, a multiscale model available in the literature was chosen, reproduced

and his features analyzed and compared with experimental evidences. In this model it is considered an Represen-
tative Volume Element (RVE) composed by a matrix with a small volume fraction of ductile damaging inclusions.

A homogenization scheme is formulated according to the Mean Field Homogenization (MFH) approach and the
Mori-Tanaka solution. The mechanical behavior is limited to small deformations and disregards heat generation.
The predictive fatigue life curves for High Density Polyethylene (HDPE) were reproduced and the contribution of
this paper focuses on the sensitivity analysis of the model to load effects and inclusion material parameters.