Optimization Approaches in Design for Additive Manufacturing

Abstract

Nowadays, topology optimization and lattice structures are being re-discovered thanks to Additive Manufacturing technologies, that allow to easily produce parts with complex geometries.The primary aim of this work is to provide an original contribution for geometric modeling of conformal lattice structures for both wireframe and mesh models, improving previously presented methods. The secondary aim is to compare the proposed approaches with commercial software solutions on a piston rod as a case study.The central part of the rod undergoes size optimization of conformal lattice structure beams diameters using the proposed methods, and topology optimization using commercial software tool. The optimized lattice is modeled with a NURBS approach and with the novel mesh approach, while the topologically optimized part is manually remodeled to obtain a proper geometry. Results show that the lattice mesh modelling approach has the best performance, resulting in a lightweight structure with smooth surfaces and without sharp edges at nodes, enhancing mechanical properties and fatigue life.

Mechanical and FEA-Assisted Characterization of Fused Filament Fabricated Triply Periodic Minimal Surface Structures

“…Nowadays, owing to the involvement of additive manufacturing (3D Printing) techniques, topology optimization through lattice designs, has been studied experimentally and it could be applied in various industries; indicatively in aerospace, automotive, biomechanical engineering and so forth [1,2]. There is a plethora of lattice structures either naturally formed (foams, bones etc.)…”

Analysis of a Preliminary Design Approach for Conformal Lattice Structures

“…In the first subsection, the modeling methodology based on NURBS free-form deformation is described; in the second subsection, the size optimization method is briefly explained; in the third subsection, the validation methods through the beam linear structural analysis are described. The case study is a piston rod previously investigated by Rosso et al [54,55]. Figure 1 shows the main dimensions of the test case, highlighting in green the design space that was replaced by lattices.…”

“…As an input, the method requires the wireframe model, the material properties, the boundary conditions, and the size constraints. Finally, the iterative FEA is run, varying the beam size to obtain the desired utilization for each element inside a predefined range [54]. Then, each array is morphed by the NURBS-FFD method to fit inside the design space of the piston road, while the straight elements of the cells are transformed into curve elements.…”

“…In the case study, the cage is governed by 5 control points in X-direction, 2 control points in Y-direction, and 3 control points in Z-direction (Figure 3b). Two different load cases are applied, a traction load case of 7.5 kN for comparing the result with the previous work of Rosso et al [54] and a compression load case of −10 kN for evaluating the structure's stability and buckling effects. The load is evenly applied to the nodes of the beams connected to the big rod's end (Table 1).…”

“…As an input, the method requires the wireframe model, the material properties, the boundary conditions, and the size constraints. Finally, the iterative FEA is run, varying the beam size to obtain the desired utilization for each element inside a predefined range [54].…”