Design and Topology Optimization of Lattice Structures Using Deformable Implicit Surfaces for Additive Manufacturing

Abstract

Additive manufacturing (AM) enables creation of objects with complex internal lattice structures for functional, aesthetic, structural and fabrication considerations. Several approaches for lattice generation and optimization, and their implementations in commercial systems exist. However, these commercial systems are typically independent from a CAD system, and therefore introduces workflow complexities for product lifecycle management. In this paper, we present a unified computer-aided framework for design, computer-aided engineering analysis (CAE) of solids with lattice structures, and freeform topology optimization within the CAD system that enables a seamless workflow. The proposed framework takes as input a solid CAD model and enables rapid generation of different lattice structures as repeated arrangements of lattice template shapes that replace input solid volume. Generated internal patterns are further optimized through freeform modifications to improve structural characteristics of the input model. Lattice modeling and optimization is performed using discrete implicit surface representations for the ease in representing complex topologies and performing modeling and freeform deformation operations. The output of the proposed framework is a polygonal represenatation of the lattified model ready for 3D printing. We have implemented our framework as a plugin to the Siemens PLM NX software system and examples are demonstrated for typical products in aerospace, medical and automotive industries.

Investigation of compressive deformation behaviors of cubic periodic cellular structural cubes through 3D printed parts and FE simulations

“…The skeleton was then thickened to form the actual lattice shape. Similar frameworks also exist in the prior works, for example, Arisoy et al (2015) and Gorguluarslan et al (2017). Arisoy et al demonstrated the generation of lattices by repeating the userdesigned lattice template shape along an axis aligned grid within their own geometric representation.…”

“…The implicit surface, C, is represented by the zero level set of f . f can be represented as isosurface functions, signed distance functions or discrete signed distance fields (Maldovan and Thomas, 2009;Arisoy et al, 2015;Pasko et al, 2011;Rumpf et al, 2015;Yoo, 2011b;Wang, 2007;Jones et al, 2006;Osher et al, 2004).…”

“…A general approach to lattifying models includes shelling a solid model, filling the designated internal space with a grid of cells, determining the geometry of each lattice cell and combining them to create the complete lattice models (Chen, 2007;Arisoy et al, 2015;Pasko et al, 2011;Hutmacher et al, 2004). The modeling based on implicit surfaces simplifies the lattice generation process and enables easy supplementary modifications such as blending, shape deformation and orientation alteration (Arisoy et al, 2015;Pasko et al, 2011;Bloomenthal and Bajaj, 1997).…”

Geometric modeling of advanced cellular structures with skeletal graphs

“…Iso-surface extraction creates a mesh template from the object's surface for the cellular structure, facilitating the handling of complex geometries. However, this method is computationally intensive and has difficulties with high-curvature or complex topology surfaces [36,33]. Lastly, generative design pipelines offer automated modeling, analysis, and inverse design solving of conformal cellular structures through integrated optimization and FEA frameworks [37].…”

Lattice Structures Built with Different Polygon Hollow Shapes: A Review on Their Analytical Modelling and Engineering Applications

“…They are typically used to build lightweight [8] and robust structures [7,8] in engineering applications. Taking advantage of polygonal hollow shapes in lattice structures gives an added level of design flexibility [7,9]. Hollow polygonal shapes, including hexagons, triangles, rectangles/squares, and circles, provide numerous benefits [7] in lattice structures.…”