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Solid Finite Element Modeling of
structural assemblies Solid Finite
Element modeling is employed to provide high-fidelity representation of the
explored concepts and realistic prediction of structural behavior. A combined
Matlab-Abaqus environment has been devised for this purpose, which generates
2D and 3D structural assemblies featuring arbitrarily complicated geometries
in an automated and fully parametrized fashion. Geometry and material
parameters are provided as inputs to a Matlab script, which produces an ASCII
file in the Abaqus .jnl format. This file contains a description of
operations required for Abaqus to generate the desired structure. The
procedure is illustrated in Figure 1. |
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Figure 1: Combined Matlab-Abaqus
environment for generation of solid FE models of relevant structural
assemblies. |
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IAIR concept implementation Practical
realizations of IAIR and chiral cells for structural assemblies are being
designed and analyzed with the implemented solid modeling environment. The
concepts of vibration control through internal resonators and through
viscoelastic damping are combined by employing viscoelastic materials in the
realization of elementary cells. An IAIR-based design under investigation is
shown in Figure
2(a). The assembly is composed by an aluminum box
beam representing the backbone structure, filled with a lattice of IAIR-based
unit cells. Ligaments of these cells are made of a rubber-like viscoelastic
material, while steel cylinder inclusions are used as resonating masses. The tip frequency response of the assembly
in a clamped-free configuration is plotted in Figure 2(b). Simulations predict strong attenuation of
the outer frame vibration around its first natural frequency when the
resonating system is inserted. |
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Figure
2: (a) Structural assembly with
box beam and visco-IAIR lattice inclusion. (b) Tip frequency response of the
box beam before (blue) and after (red) insertion of the resonating system. |
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Chiral concept implementations Using
a similar approach to that described above, structural assemblies composed of
a box beam and inclusions in the shapes of chiral lattices with different
properties are currently under investigation. Figure 3 shows four different designs: (a) uniform-size chiral lattice, (b) lattice with graded masses, (c) anisotropic (stretched) lattice
with lightweight annular masses, and (d)
anisotropic lattice with graded masses. Cell ligaments in all lattices are made
of a viscoelastic material. Corresponding frequency responses predicted by
FEM simulations are reported in Figure 3(e). Wide bandgaps at moderately high frequency
are produced by almost all configurations, while different degrees of
vibration control at low frequencies are achieved, as can be seen from the
zoomed view of Figure 3(f). For example, design (c) provides the flattest response in the [0, 20] Hz range, while
design (d) allows for vibration
damping over a very wide frequency range. So a class of different assemblies
can be devised to meet a broad range of specifications. |
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Figure
3: (a)-(d) Visco-chiral
assemblies. (e) Corresponding frequency responses compared to that of the box
beam without inclusions (blue line). (f) Zoomed view of (e) in the [0, 50] Hz
range. |
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Georgia
Institute of Technology – Contact Us: |
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Massimo Ruzzane Emanuele Baravelli |
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