A Hybrid Geometric Modeling Method for Large Scale Conformal Cellular Structures

This paper presents a hybrid geometric modeling method to create CAD models of large-scale conformal cellular structures effectively and efficiently. Cellular material structures can be engineered at the mesoscopic scale for high performance and multifunctional capabilities. One type of cellular structure is conformal lightweight truss. A simple method of constructing models of uniform trusses is to pattern unit cells linearly within a CAD system. However, by orienting strut directions and adjusting strut sizes, such trusses can be optimized to achieve superior strength, stiffness, and weight characteristics. For large truss structures, computational and storage complexities cause difficulties in CAD system modeling. In this paper, a new hybrid geometric modeling method by using both solid modeling and surface modeling techniques is developed to directly create tessellated models and automate the geometric modeling process of conformal truss structures efficiently. This hybrid modeling method is intended to support the design, analysis, optimization, and manufacture of conformal truss structures. Examples are presented and the computational efficiency of the hybrid method is compared with the approach of creating the complete solid model of cellular structures. The hybrid geometric modeling method can be generalized to various types of cellular structures as well as other periodic structures.