Effects of infill characteristics and strain rate on the deformation and failure properties of additively manufactured polyamide-based composite structures

Abstract

Additive manufacturing is one of the advanced manufacturing methods for producing cellular composites with desired infill patterns. Previous studies of the influence of the printing infill characteristics on the material mechanical properties have mainly focused on stiffness and strength. Limited work revealed that printing infill patterns also influenced the plastic deformation and failure mechanisms of composite structures. The present work aimed to systematically investigate the effects of infill parameters and tensile strain rate on the elastoplastic deformation and failure behaviors of polyamide-based composite structures, built by fused deposition modeling (FDM) process. The mechanical investigations were conducted combined with the capture of morphological evolution. The effects of infill pattern, infill density, and tensile strain rate on the mechanical properties and relative energy absorption of the composite structures were analyzed. The infill pattern was one of the deterministic factors for the deformation and failure modes, mainly due to the defects caused by the printing path. Besides, higher infill densities produced more imperfections, causing lower elongation at break of the composite structures. However, the strain rate has a limited influence on deformation and failure properties for the composite structures.