3D printed stretching-dominated micro-trusses. (15th November 2017)

• Record Type: Journal Article
• Authors: Kaur, Manpreet; Yun, Tae Gwang; Han, Seung Min; Thomas, Edwin L.; Kim, Woo Soo
• Is Part Of: Materials & design. Volume 134(2017)
• Page Start: 272
• Page End: 280
• Publication Date: 2017-11-15
• Subjects: Architected material -- Micro-truss -- 3D printing -- Stretching-dominated structures -- Compressive stress and strain; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2017.08.061
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: Micro-architectures, such as cellular truss structures, enhance the mechanical properties of structural materials while ensuring that they are lightweight in nature. Among others, stretching-dominated truss structures are known for their high modulus and yield strength, which makes them the best choice for lightweight structural applications. Finite element analysis of octahedral vs. octet structures is used to compare the differences in stress distribution in the stretching-dominated deformation of such trusses. Both octahedral and octet stretching-dominated structures were fabricated by fused deposition modeling (FDM)-based three-dimensional (3D) printing. These micro-architectures are printed with different polymeric materials, such as polylactic acid or polylactide (PLA), nylon 618, and a carbon fiber reinforced composite of PLA (CFRPLA). In addition, the CFRPLA filament with randomly suspended carbon fibers in PLA undergoes shear-induced alignment along the strut direction of the 3D printed micro-trusses, which leads to an improved Young's modulus as compared to the other materials. The properties of the 3D printed stretching-dominated micro-trusses are evaluated by compression testing, finite element analysis (FEA), and thermal analysis. The 3D printed octet structure of CFRPLA with fiber alignment exhibits the highest modulus and yield strength of 0.6 GPa and 17 MPa, respectively. Graphical abstract: Highlights: Stretch-dominated and bending-dominated micro-trusses are fabricated by FDM-based 3D printing with 100 micrometers in strut diameter. Stretch-dominated octet micro-truss is mechanically programed by 3D printing with rigid and soft materials 3D printed CFRP truss shows strengthened mechanical properties resulted from shear-induced alignment of fibers along the 3D printing direction.