Crack morphology in lattice-core specimens made of biopolymer via fused deposition modelling

Proceedings of: The 7th International Conference on Crack Paths (CP 2021), 21-24 September 2021, virtual format.During the last decades, it has been shown how additive manufacturing is becoming a cost-efficient alternative to produce customized parts or prototyping with traditional manufacturing processes. However, the integrity assessment of 3D printing technology parts is still challenging due to the huge number of parameters involved during the process along with the lack of industry standards. Therefore, further investigations are required to optimize the in-service behaviour of additive manufacturing parts. The objective of this work is to analyse the failure of components made from additive manufacturing under three-point bending tests in terms of crack morphology and strength. Specimens were made by a biopolymer (polylactic acid, PLA) via fused deposition modelling with different infill core densities. Next, three-point bending tests were carried out at a low strain rate under monotonic loading. In addition, three-dimensional digital image correlation was applied during tests in order to track the exterior full-field displacement and strain and output crack trajectories. The results are analysed in terms of fracture morphology and flexural strength of the post-mortem specimens, and they show the high impact of process parameters in the mechanical behaviour and failure of components made from additive manufacturing.The authors gratefully acknowledge the funding support received from the Spanish Ministerio de Ciencia e Innovación for funding the project PID2020-112628RA-I00 and the Comunidad Autónoma de Madrid through the project IND2020/IND-17413