Additive Manufacturing Along Principal Stress Lines

Kam-Ming Mark Tam, Caitlin T. Mueller
2017 3D Printing and Additive Manufacturing  
Optimization techniques developed for additive manufacturing (AM) to maximize the structural stiffness of printed parts are often computationally expensive reformulations of classical procedures that do not typically consider the mechanical behavior introduced to the printed part by the AM fabrication process, which is layerbased, and result in pieces with significant anisotropy. The misalignment of filament orientation and structural action negates the potential benefits of optimization.
more » ... optimization. Addressing this problem, this article presents a two-part research approach exploring a new method of material deposition called Stress Line Additive Manufacturing (SLAM), which deposits filament along paths derived from principal stress lines. The proposed method unifies the design and optimization of the geometry and filament layout of AM-produced parts, and is compatible to the operational characteristics of fused deposition modeling (FDM). Experimentally validating the structural significance of oriented filament, the first part of the research implements SLAM on a commercial platform for planar design cases. Ongoing research to adapt SLAM for complex 2.5D surface geometries using a six-axis industrial robot arm and a custom-designed heated extruder is then presented in Implementation 2: Robot-Enabled SLAM for 2.5-D Cases. The presented research opens new possibilities for structurally performative fabrication. Opposite page: To validate the capacity of the robotic adaptation of Stress Line Additive Manufacturing (SLAM) in producing high-performing complex 2.5-D surface geometries, the research presented here generated and fabricated four SLAM specimens based on the stress line information of a form-found four-support gridshell analyzed under various loading conditions. As the figure shows, these load cases include distributed load (labeled SL-DL), point load (SL-PL), asymmetrically distributed load (SL-ADL), and lateral load (SL-LL). Structural load testings were subsequently carried out on SL-DL and SL-PL-showing that the SLAM cases registered improvement in stiffness, ultimate strength capacity and ductility after initial failure in comparison to specimens produced using commercial additive manufacturing platforms. Photo credit: Digital Structures.
doi:10.1089/3dp.2017.0001 fatcat:hxgfiutcoje75nakv4tpvfx3ei