Prof. Stefano Mariani
Politecnico di Milano, Dipartimento di Ingegneria Civile e Ambientale, Milano, Italy
Title: Active truss metamaterials: modelling and tuning of band gaps
Abstract:
Periodic composite structures like acoustic
metamaterials (AMMs) and phononic crystals (PCs) are able to forbid the
propagation of sound and elastic waves for some specific frequency ranges,
leading to the emergence of so-called band gaps. So far, the optimization to
attain sought band gaps, has been performed on passive PCs and AMMs. Hence, the
band gap properties cannot be changed anymore after the production process of
the materials. This problem can be overcome thanks to the use of active
materials. In this work, both material and geometric non-linearities are
exploited to actively tune the frequency ranges of the band gaps of an AMM
characterized by a three-dimensional periodicity. Specifically, a piezoelectric
hyperelastic composite, obtained by embedding piezo-nanoparticles in a soft
polymer matrix, is adopted to assess the effect of nonlinearities on the behavior
of sculptured micro-structures, taking also advantage of instability-induced
pattern transformation and piezoelectricity on the active tuning of the band
gaps.
Keywords: acoustic metamaterials, hyperelasticity, multi-physics,
piezoelectricity, buckling
Biography:
Dr. Stefano Mariani received an M.S. degree (cum laude) in civil engineering in 1995 and a Ph.D. degree in structural engineering in 1999, both from the Polytechnic University of Milan.He is currently an associate professor at the Department of Civil and Environmental Engineering of the Polytechnic University of Milan. He was a research scholar at the Danish Technical University in 1997, an adjunct professor at Penn State University in 2007, and a visiting professor at the Polytechnic Institute of New York University in 2009.He is a member of the Editorial Boards of Algorithms, International Journal on Advances in Systems and Measurements, Inventions, Machines, Micro and Nanosystems, Micromachines, and Sensors. He has been a recipient of the Associazione Carlo Maddalena Prize for graduate students (1996), and of the Fondazione Confalonieri Prize for PhD students (2000). His main research interests are: reliability of MEMS that are subject to shocks and drops; structural health monitoring of composite structures through MEMS sensors; numerical simulations of ductile fracture in metals and of quasi-brittle fracture in heterogeneous and functionally graded materials; extended finite element methods; calibration of constitutive models via extended and sigma-point Kalman filters; multi-scale solution methods for dynamic delamination in layered composites; smart materials and structures.