Improving the fracture toughness of 3D printed thermoplastic polymers by fused deposition modeling

This work describes a new filament deposition in fused deposition modeling process through criterion based on mechanical stress. This criterion requires that the filaments' directions to follow the principal directions of the stress in the sample. The article also presents several Crack-test specimens that have been printed with and without respect to this criterion. The fracture behavior of these specimens has been investigated. The results show that criterion leads to an improvement of 30% in the fracture toughness. Digital image correlation has been extensively used to study the local strain field in the specimens. The strain cartographies reveal a drastic change in fracture behavior. The modification of filament direction leads to ductile-like behavior in crack extension which is characterized by a large deformation zone associated with a slow crack growth rate during the crack propagation.