Abstract:
Saving material and improving strength are two important but conflicting requirements in 3D printing. We propose a novel method for designing the internal supporting frame structures of 3D objects based on their medial axis such that the objects are fabricated with minimal amount of material but can still withstand specified external load. Our method is inspired by the observation that the medial axis, being the skeleton of an object, serves as a natural backbone structure of the object to improve its istance to external loads. A hexagon-dominant framework beneath the boundary surface is constructed and a set of tree-like branching bars are designed to connect this framework to the medial axis. The internal supporting structure is further optimized to minimize the material cost subject to strength constraints. Models fabricated with our method are intended to withstand external loads from various directions, other than just from a particular direction as considered in some other existing methods. Experimental results show that our method is capable of processing various kinds of input models and producing stronger and lighter 3D printed objects than those produced with other existing methods.

Furthermore, we explore NURBS based geometric description and isogeometric analysis in the design of self-supporting masonry surface. Using NURBS we can obtain smooth self-supporting surface with relatively small number of control points. The mechanical property of the surface is simulated by the isogeometric analysis, which can handle surfaces with complex topology and free or fixed boundary conditions. A simple and robust form finding algorithm is designed to get a self-supporting shape which is closest to the given one. Compared with mesh description and thrust network analysis methods, our method have the advantage to design self-supporting surfaces with high order smoothness and better efficiency.

Bio:
Dr. Yang XIA obtained his bachelor degree in engineering mechanics from Wuhan University in 2007 and then gained his Ph.D. degree in computational mechanics from Dalian University of Technology in 2013. Since 2013, he joined School of Automotive Engineering, Dalian University of Technology and is currently an assistant professor. His research deals with geometry based simulation and fabrication, which focuses on the isogeometric analysis and structural optimization in 3D printing.