Phononic Characteristics of Lattice Structures: ....

..From Theoretical and Computational Aspects to Applications
in Smart Multifunctional DevicesDr. Stefano Gonella,
Department of Mechanical Engineering, Northwestern UniversityAbstract:
Within the family of periodic solids, lattice structures and cellular materials have been the object of special scientific interest as a result of their unique mechanical and thermal properties and their excellent strength-to-weight ratio, which make them ideal for automotive and aerospace engineering applications. One well-known example is represented by hexagonal and auxetic honeycomb structures, which are used in conventional sandwich plates as well as in "truss-core" composite beams. Analysis of the wave propagation characteristics of these structures reveals a whole new set of peculiar mechanical properties, which suggests applications in novel smart structures and metamaterials. The phenomenon of phononic bandgaps, for instance, can be exploited to design tunable vibration isolation devices and mechanical filters. The directionality of the elastic wavefields for specific frequencies of excitation suggests the possibility to design frequency-controlled waveguides and directional actuators and sensors. Finally, the interplay between phononic characteristics and piezoelectric microstuctures can be used to envision a new class of multifunctional devices for energy generation and conversion.In this presentation, a finite-element-based homogenization technique is
introduced to extract the equivalent dynamic properties of lattices with arbitrary internal geometry. A computational unit cell approach is then used to investigate the in-plane phononic characteristics of hexa-chiral lattice structures. Finally, a novel concept is presented for piezoelectric microstructured devices combining vibration isolation and
energy harvesting capabilities.

Location: Kaprielian Hall (KAP) - 209

Audiences: Everyone Is Invited

Contact: Evangeline Reyes