| Popis: |
Additive manufacturing (AM) technologies are catching the interest day by day due to their ability to produce very complex shapes or geometries. Investigating the fracture and fatigue behavior of additively manufactured parts are essential not only to understand their mechanical response but also to predict and prevent their failure. In this study, fracture and fatigue properties of additively manufactured polymers are investigated experimentally combining the servohydraulic material testing system (MTS 810) and the three-dimensional digital image correlation technology. The polymers used for the analysis are acrylonitrile styrene acrylate (ASA) and Onyx, which are readily available and more prevalent in AM applications. Both notched (i.e., pre-cracked) and unnotched specimens are printed in the edge and flat orientations by the fused deposition modeling printer in the shape of the standard ASTM sub-size flat dogbone structure. The tensile strain is studied ahead of the crack formation, and the crack propagation is observed in the photos obtained from the digital image correlation system. A finite element model of similar contemplation is generated for the validation and extended results. Results show that the orientation of manufacturing has a noticeable effect on the failure of the specimen. In the unnotched specimens, the crack occurs near the neck due to a high-stress concentration. Results for the high cycle fatigue test indicate that fatigue life decreases as the load increases for all types of specimens. |
