Ph.D. Dissertation Defense by
Hongqing Vincent Wang
Tuesday, November 15, 2005
(Dr. David W. Rosen, Chair)
"A Unit Cell Approach For Lightweight Structure And Compliant Mechanism"
Cellular structures are present from the atomic level all the way up to patterns found in the human skeleton. They are naturally adored for their excellent mechanical, thermal and acoustic properties. Two typical types of cellular structures, lightweight structures and compliant mechanisms, are investigated in this research. Lightweight structures are rigid and designed for the least weight, high strength and stiffness. Compliant mechanisms are designed for compliance to transform motion and forces. Most designed lightweight structures are patterns of primitives. However, using conformal cellular structures with adaptive strut orientations and sizes, like the trabeculae in femoral bone, the performance of lightweight structures can be enhanced. It is important to consider the nonlinearities of compliant mechanisms and desired to design large-scale mechanisms. However, nonlinearity and scalability have not been fairly studied in the existing research.
In order to design conformal cellular structures, a new unit cell, the unit truss is proposed in this research. The unit truss approach facilitates the design of conformal cellular structures for enhanced mechanical properties via geometric modeling, finite element analysis, topology and shape optimization, and additive fabrication. Four research questions, which address representation, structural analysis, design synthesis, and manufacturing respectively are raised and answered. Unit truss has the least interaction between unit cells and it enables representation and mechanics analysis for large-scale