Mode I critical energy release rate of additively manufactured polyamide samples

One accepted cause that generates low mechanical strength and/or fracture properties is the presence of defects in the structure of the material. Additive Manufacturing does not except this rule, especially the powder bed fusion technologies that relays on powder spreading through a mechanical blade or roller followed by laser sintering or melting. The paper presents experimental investigations on fracture properties of polyamide PA2200 samples obtained by selective laser sintering. The mode I critical energy release rate and mode I fracture toughness were determined in accordance to ASTM D 5528-01 for four sets of samples: one set without induced geometrical defects, and three other sets having interlayer and intralayer defects. The results consist of geometrical evaluation of the samples and error computing on one-hand and fracture properties on the other hand. In addition, a study on absorbed energy in the defect section of samples was conducted, leading to a direct correlation between the defect percentages (0.0%, 0.1%, 0.3% and 0.5%) and the absorbed energy.