Multi-scale Computer-Aided Design for additive manufacturing

Additive Manufacturing (AM) technologies enable the fabrication of parts and devices that are geometrically complex and can have complex material compositions. To take advantage of these capabilities, Computer-Aided Design systems must be able to represent many thousands of geometric elements and understand how materials behave, which current CAD systems based on parametric, solid modeling approaches can not accomplish. We present new design and CAD technologies to achieve these objectives. For complex geometries, a new representation has been developed and demonstrated on a wide range of cellular materials (lattices, honeycombs, etc.). This representation has been used as the basis for a very efficient optimization method for designing lightweight structures. For understanding materials, an approach for integrating material process-structure-property relationships into CAD models has been developed that uses a common set of basis functions for representing both macro-scale part geometry and the micro-scale geometry of material microstructures (grains and fiber or particle reinforcements). Surfacelets(extensions of wavelets) are the basis functions that are used to construct a multi-scale, heterogeneous geometric/material representation. Examples of aerospace parts and AM materials illustrate the technologies.