Strengthening in fracture toughness of a smart material manufactured by 3D printing

Additive Manufacturing is increasingly important, not only in prototyping but also in industrial production. Consequently, understanding and improving mechanical behaviors of materials used and produced by layers manufacturing are major issues. A previous work, reported in Gardan et al. (2016, 2017), aimed at developing and testing a new method that uses a specific trajectory deposition by Fused Deposition Modeling (FDM). The previous study suggested a method to enhance the 3D printing trajectories through the digital phase to reproduce the principal stresses direction. A "smart deposition" was applied to Compact Tension CT specimens (pure mode I fracture) and showed an improvement of 30% in the fracture toughness. In addition, the fracture behavior changed from a brittle to a ductile like behavior. However, the previous study was not sufficient to well understand the mechanical behavior of smart material when submitted to multi-axial loading. Thus, the new study applies the previous method to mixed mode loading (mode I+II) in order to contribute to better understanding of smart material's behavior. After applying the process on new bending specimens, the outcomes show an increase of 30% in fracture toughness through a comparison between classic specimens and optimized specimens. (C) 2018, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.