seminar Anna Pandolfi.pptx

seminar
Metaconcrete: Engineered aggregates
for enhanced dynamic performance
Anna Pandolfi
Politecnico di Milano, Dipartimento di Ingegneria Strutturale
The seminar will be held at Roma Tre University
Department of Engineering - via Vito Volterra, 62, Rome
Wednesday 3 February 2015 - Seminar Room - 11:30-12:30
Metaconcrete: Engineered aggregates for
enhanced dynamic performance
Abstract. Recent progress in the field of metamaterials science has led to a range
of novel composites which display unusual properties when interacting with
electromagnetic, acoustic, and elastic waves. Metaconcrete is a new structural
metamaterial with enhanced wave attenuation properties for dynamic loading
applications. In this new composite material the standard stone and gravel
aggregates of regular concrete are replaced with spherical engineered inclusions.
Each metaconcrete aggregate has a layered structure, consisting of a heavy core
and a thin compliant outer coating. This structure allows for resonance at or near
the eigenfrequencies of the inclusions, and the aggregates can be tuned so that
resonant oscillations will be activated by particular frequencies of an applied
dynamic loading. The activation of resonance within the aggregates causes the
overall system to exhibit negative effective mass, which leads to attenuation of
the applied wave motion. To investigate numerically the behavior of metaconcrete
slabs under a variety of different loading conditions a finite element slab model
containing a periodic array of aggregates is utilized. The various analyses
presented in our studies provide the theoretical and numerical background
necessary for the informed design and development of metaconcrete aggregates
for dynamic loading applications, such as blast shielding, impact protection, and
seismic mitigation. The work has been developed in collaboration with Stephanie
J. Mitchell (Caltech), Michael Ortiz (Caltech) and Deborah Briccola (Polimi).
References
S. J. Mitchell, A. Pandofi, and M. Ortiz. Effect of brittle fracture in a metaconcrete
slab under shock loading. Journal of Engineering Mechanics,ASCE,142, 2016.
S. J. Mitchell, A. Pandolfi, and M. Ortiz. Investigation of elastic wave transmission
in a metaconcrete slab. Mechanics of Materials, 91:295-303, 2015.
S. J. Mitchell, A. Pandolfi, and M. Ortiz. Metaconcrete: designed aggregates to
enhance dynamic performance. Journal of the Mechanics and Physics of Solids,
65:69-81, 2014.
Anna Pandolfi
2001-to date: Associate Professor of Structural
Mechanics, Politecnico di Milano, Italy.
1996-to date: Visiting Associate in Aerospace, Caltech,
Pasadena CA, USA.
PhD in Mechanics, LPMM, Université Paul Verlaine de
Metz, France.
MS in Civil Engineering, Structural Engineering,
Politecnico di Milano.