IGM Colloquium: From ferroelectric ceramics to their struct. analogs
What do active ceramics and soft structures have in common? Two seemingly distinct systems serve to illustrate the power of structural transformations, and the challenges involved in modeling those across scales.
Ferroelectric ceramics are key to most sensor and actuator technologies, owing to their electro-mechanical coupling: they deform under applied electric fields, and they produce electric charges under deformation. What is frequently exploited at the device level, has a complex origin at the atomic scale, whose understanding hinges upon models and techniques that bridge from the atomic scale of angstroms and femtoseconds all the way up to millimeters and seconds. We discuss how information from all scales can be combined into simulations that predict the macroscale material behavior in comparison with experiments. Once having gained insight into the fundamental mechanisms, we seek structural analogs of the ferroelectric switching; i.e., we discuss how mechanical structures or metamaterials can be conceived, which not only mimic some of the atomic-scale phenomena of structural transformations qualitatively but can even be described quantitatively by the same models. In summary, we discuss – through theory, simulations and experiments – the path from ferroelectric ceramics to their structural analogs.
Professor Dennis Kochmann received his Diploma and his doctoral degree in Mechanical Engineering from Ruhr-University Bochum in Germany. He also received a Master’s degree in Engineering Mechanics from the University of Wisconsin-Madison where he spent one year as a Fulbright fellow. He was a postdoc at the University of Wisconsin as well as a Humboldt fellow at Caltech before joining the faculty of the Aerospace Department at Caltech in September 2011. From 2011 to 2017 he was Assistant and later Full Professor of Aerospace at Caltech, before moving to ETH Zurich as Professor of Mechanics and Materials in April 2017. His research focuses on the link between structure and properties of a variety of materials and employs methods of theoretical, computational and experimental mechanics (including continuum and atomistic modeling, scale-bridging, multiscale models, phase field techniques, and experimental material characterization). He also develops novel materials with controllable properties by careful microstructural architecture. His research has been recognized by, among others, the Bureau Prize in Solid Mechanics form IUTAM, the Richard von Mises Prize by GAMM, an NSF CAREER Award, the T.J.R. Hughes Young Investigator Award by the ASME and, recently, an ERC Consolidator Grant.