On the orthotropic elasto-plastic material response of additively manufactured polyamide 12

摘要

The mechanical response of polymers such as polyamide 12 (PA-12) manufactured through additive manufac-turing, is significantly affected by the layered manufacturing approach and the printer settings used during the creation of the parts. As a result, the mechanical performance can differ significantly from PA-12 parts creat-ed through conventional techniques such as injection molding, and a detailed study of the material mechanical behavior is necessary. This work presents an in-depth study of the response of PA-12 to tensile loading and the challenges involved in obtaining qualitative and repeatable results. The full elasto-plastic curves are meas-ured during tensile testing and the effect of printing direction is taken into account in order to investigate whether orthotropic material behavior can be observed. All parts were manufactured using commercially avail-able selective laser sintering (SLS) printers. Digital image correlation was used extensively to obtain high-accuracy strain measurement over the entire elasto-plastic range up to failure. The results show an isotropic elastic response of PA-12, with orthotropic failure properties and the presence of significant viscous contribu-tions in the material response.