APL Colloquium

March 26, 2021

Colloquium Topic: Magneto-Active Composites, Multi-Field Processing, and a Quest for a Universal 3D Printer

Can we develop a platform in which printing across a range of material functions is no more expensive or complex than printing with a sole function in mind? For example, consider printing a working electric motor versus a simple shelf bracket.  The printed motor would require (at a minimum) electrically conductive pathways as well as insulation; magnetic and non-magnetic regions; and mechanical stiffness in general with possible damping in specific locations. The bracket, however, needs simply to be stiff enough to hold its shape under load.

While the $3B and growing additive manufacturing industry is built on the paradigm of “free shape complexity”, which asserts that geometric complexity of a part should not necessarily scale its production cost, a next technical plateau could be defined as “free functional complexity”. Along these lines, several researchers and commercial ventures have developed “multi-material” printers capable of fabricating monolithic parts with multiple material functionalities. These print platforms are often expensive, achieving their success by drawing from multiple discrete reservoirs of materials to serve each purpose. Being both expensive and complicated print platforms, however, these approaches, while relatively effective, arguably violate the new paradigm: the broadening of functionality is not free.

Headed by Dr. von Lockette, the Magneto-Active Composites and Structures (MACS) lab at Penn State is leading work, funded by National Science Foundation, to research how magneto-active polymers may be manipulated through the use of electromagnetic fields to produce materials with the required wide range of functionalities. Fundamentally, the processing techniques utilize dielectrophoretic and magnetophoretic actions which act on electromagnetically susceptible particles within the polymer matrix to create variable microarchitectures prior to curing. In essence, we force the particles to attract or repel themselves into preferential configurations. The resulting effective properties of those configurations then determine the bulk properties. The science underlying our “quest” for a universal printer turns into a search through a complex composition – processing – property – structure design space. And, as with any quest there are hidden treasures to be found (novel control of magnetic susceptibility, for one) and wisdom to be gained – such as an answer to whether, or not, free functional complexity even exists.

This talk will highlight the work of our group, and others, working on the development of multi-field processing techniques with respect to polymer matrix composites with an emphasis on how these techniques fit the existing landscape of multi-material 3D printing. Additionally, I will highlight interesting developments with respect to unexpected material responses and applications from our group and other researchers, all on a similar quest.

Colloquium Speaker: Paris R. von Lockette

Dr. Paris von Lockette earned his PhD in Mechanical Engineering from the University of Michigan in 1999 after receiving his B.S. in Engineering Science from Trinity University in San Antonio, Texas in 1993. His research, rooted in processing – structure – property relationships of electromagnetically sensitive polymer matrix composites, has sought to link the electro-, magneto-, and elasto-mechanical response of microstructural morphologies to their macroscopic properties, and ultimately to the design of the devices that use them. Moreover, his research seeks to directly link constituent processing techniques to the evolution of those morphologies, giving traditional application-focused designers new tools to locally tailor properties.

He was a founding member of the mechanical engineering department at Rowan University in New Jersey, where he worked for twelve years. During one of those years he held a visiting scientist position in mechanical engineering at Rutgers University in New  Brunswick, NJ.   After leaving Rowan, he joined  Penn State, University Park, where he is currently an associate professor of mechanical engineering. Dr. von Lockette was also recently elected a Fellow of the American Society of Mechanical Engineers (ASME).

Dr. von Lockette's work is rooted in the structure property relationships of elastomers and elastomer composites. He has received funding from the National Science Foundation for the study of piezoelectric-rubber composites for vibration isolation and control; for the acquisition of an atomic force microscope to study the mechanical response of rubbery composites and materials at the nanoscale; for x-ray tomography and diffraction systems to study the micromechanics of magneto-active composites; to examine multi-field active materials for Origami Engineering; and, most recently, to develop cutting-edge 3D printing technologies.  https://www.pvonlock.org/about-me

Dr. von Lockette  has decades of experience in the fabrication, computational simulation, and opto-, magneto-, and electro-mechanical testing of polymeric composites with several publications in journals such as the Mechanics and Physics of Solids, Journal of Mechanisms and Robotics,  Macromolecules, Polymer, Acta Mechanica, The Journal of Computational and Theoretical Polymer Physics, and Smart Materials and Structures. His most recent work involves the study and optimization of composites and structures comprised dipole-driven electromagnetically sensitive particulates composites. This work involves experimental characterization of electromagnetic properties and micro-architectures, computational multi-physics simulation / optimization of self-organization into those architectures, and development of multi-field-assisted additive manufacturing techniques.

Over his career he has received federal and industrial funding to conduct research and consult on polymer composites in a range of contexts including network topology-based strengthening mechanisms, tunable piezo-composite resonators, magneto-active composites, origami engineering, design of novel biomedical and defense-related devices,  and, most recently, multi-field processing for additive manufacturing. He is actively pursuing a multi-scale experimental-analytical-computational framework for the microstructural optimization of multi-field material systems. Dr. von Lockette has a lengthy record of developing educational and outreach programs, especially to underrepresented groups (such as the STEM Academy at Rowan – STAR).  He currently heads the Magneto-Active Composites and Structures (MACS) Lab at Penn State.