Abstract: Material properties are governed by the chemical composition and spatial arrangement of constituent elements at multiple length-scales. This fundamentally limits material properties with respect to each other creating trade-offs when selecting materials for specific applications. For example, strength and density are inherently linked so that, in general, the more dense the material, the stronger it is in bulk form. We are combining advanced microstructural design, using flexure and screw theory as well as inverse methods, such as topology optimization, with advanced additive micro- and nanomanufacturing techniques to create new material systems with previously unachievable property combinations – mechanical metamaterials. The performance of these materials is fundamentally controlled by geometry at multiple length-scales rather than chemical composition alone. We have demonstrated designer properties of these mechanical metamaterials in polymers, metals, ceramics and combinations thereof. Properties include ultra-stiff lightweight materials, negative stiffness, and negative thermal expansion to name a few, as well as functional properties such electrical, optical, and chemical responses. We have primarily utilized our custom developed additive micro-manufacturing techniques to create these structures and materials. These include projection microstereolithography (PSL), direct ink writing (DIW), and electrophoretic deposition (EPD). I will also touch on new advanced manufacturing concepts such as volumetric additive manufacturing, computed axial lithography, and diode-based additive manufacturing.
Biosketch: Christopher M. Spadaccini, Ph.D., is currently the Director of the Additive Manufacturing Initiative at the Lawrence Livermore National Laboratory (LLNL) as well as the leader of the Center for Engineered Materials and Manufacturing. He has been working in advanced additive manufacturing process development and architected materials for the last decade and has over 35 journal publications, three book chapters, and several dozen patents awarded and pending. Dr. Spadaccini founded several new fabrication laboratories at LLNL for process development focused on micro and nanoscale features and mixed material printing. He received his B.S., M.S., and Ph.D. degrees from the Department of Aeronautics and Astronautics at the Massachusetts Institute of Technology (MIT) in 1997, 1999, and 2004 respectively and has been a member of the LLNL technical staff for over 14 years. He has also been a lecturer in the Chemical, Materials, and Biomedical Engineering Department at the San Jose State University where he taught graduate courses in heat, mass, and momentum transfer.
Date(s) - May 07, 2018
2:00 pm - 3:00 pm