In this one-hour seminar, Stefano Gonella, University of Minnesota, will present a talk titled,
“From Maxwell bilayers to superkagome lattices.
The fate of topological edge modes under increased geometric complexity.“
Abstract – Elastic metamaterials are structural materials that owe their unique wave
manipulation capabilities to their complex internal architecture. Topological
metamaterials are a special subclass of metamaterials whose behavior is controlled by
the topology of their phonon bands. In this talk, I will discuss the mechanics of a class
of metamaterials known as topological Maxwell lattices. While these systems have been
the object of extensive theoretical investigation, their treatment has typically been
limited to ideal configurations, confined to the static limit, and restricted to 2D
configurations.
In this talk I will address the following questions, that are both philosophical and
practical. What is the fate of topologically protected phenomena, such as topological
edge modes and polarization, when we increase the level of geometric and kinematic
complexity of the lattices, either by adding dimensions or by considering more intricate
inter-cell connectivity? What is their robustness against the onset of the structural non-idealities that are commonly encountered in realistic lattices fabricated using any of the
available additive or subtractive manufacturing methods? What new opportunities for
mechanical functionality arise from incorporating these effects in their design?
Assisted by laser vibrometry experiments, I will show that it is possible to design bilayer
structures in which coupling mechanisms transfer the in-plane topological polarization
of the individual layers to the out-of-plane degrees of freedom, leaving a strong
signature of topological polarization in the flexural response. Then I will introduce a
framework for cell augmentation, by which one can generate kagome macrocells that
can be assembled into “superkagome” lattices, and I will discuss non-trivial and
unexpected connections between the polarization of these macrocells and their
primitive counterparts.
Bio – Stefano Gonella is the James L. Record Professor in the Department of Civil,
Environmental and Geo- Engineering at the University of Minnesota. He received Ph.D.
and M.S. in Aerospace Engineering from Georgia Tech in 2007 and 2005, respectively,
following a Laurea, also in Aerospace engineering, from Politecnico di Torino in 2003.
Before joining the University of Minnesota, he was a post-doctoral associate at
Northwestern University. His research interests revolve around the modeling, simulation
and experimental characterization of dynamical phenomena in architected materials,
phononic crystals, and acousto-elastic metamaterials. His latest efforts have been
directed towards understanding the role of topological states of matter in the design of
mechanical metamaterials. He was recipient of the NSF CAREER award in 2015.
During the 2023-2024 academic year he is the William R. Kenan Visiting Professor for
Distinguished Teaching at Princeton University.
This is an in-person seminar.
If you opt to join via zoom use:
Meeting ID
835 3483 3037
Passcode
841237
Furthe questions for this hybrid event can be emailed to:
Leah Abraha
labraha@gc.cuny.edu