The research objective of this award is to test the hypothesis that scaling laws can describe the physical phenomena governing droplet generation from ultrasonic actuation of complex fluids. The primary application of ultrasonic droplet generation and deposition in this project is for the development of a scalable additive manufacturing technology that allows three-dimensional structures to be printed from complex fluids, that is, fluids with non-Newtonian behavior or which have viscosities one to two orders of magnitude higher than that of typical printable fluids. Materials of interest include polyurethanes, conductive polymers, and ceramic pastes. As a result of this proposed work, the acoustics and droplet formation physical phenomena will be identified at multiple length and time scales. Computational fluid dynamics models will be developed that capture microscopic details of the ejection process. This knowledge will be used to create design guidelines for the new ultrasonic droplet deposition manufacturing technology. If successful, this research could benefit society by enabling manufacturing technologies that can print a wide range of materials for applications ranging from complex, multi-material thermoplastic parts to photovoltaics, fuel injectors and vaccine delivery systems. Overcoming the limitations of current printing technologies will have a transformational effect on the additive manufacturing and potentially the ink-jet printing industries, since a much wider range of materials will be printable. Graduate and undergraduate students from under-represented groups will be recruited for this project. The proposed work will enhance the infrastructure for research and education by developing and maintaining facilities for atomization experiments and for part fabrication. Broad dissemination will be achieved through courses enhanced with research results, undergraduate research opportunities, active industry involvement, papers and presentations in engineering forums, and a web-site to report results and provide access to the developed additive manufacturing system.
