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Walter Lacarbonara
Dipartimento di Ingegneria Strutturale e GeotecnicaUniversità degli Studi di Roma "La Sapienza"
Via Eudossiana, 18 - 00184 Roma
e-mail: [email protected]
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Tacoma Narrows Bridge
Tacoma Narrows, USA, 11.1940 U=18.6 m/s
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Volgograd Bridge
Volgograd, Russia, 20.5.2010 U=18 m/s
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Aeroelastic phenomena
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Aerodynamic wind loads
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Loss of stability: divergence or Hopf
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Suspension bridges
l = 888 m
l = 1490 m
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Nonlinear model of suspension bridges
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Nonlinear model of suspension bridges
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Nonlinear model of suspension bridges
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Nonlinear model of suspension bridges
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Nonlinear model of suspension bridges
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Nonlinear model of suspension bridges
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Discretization (PDE mode)
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Suspension bridges: equilibrium paths
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Suspension bridges: torsional divergence
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Suspension bridges: torsional divergence
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Ponte della Musica
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Ponte della Musica
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Ponte della Musica
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Arch bridges: kinematics
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Arch bridges: kinematics
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Arch bridges: Equations of motion
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Ponte della Musica: softening behavior
÷
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Ponte della Musica: modal properties
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Ponte della Musica: frequencies
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Ponte della Musica: flutter
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Ponte della Musica: flutter
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Ponte della Musica: flutter
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Ponte della Musica: flutter mode
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Ponte della Musica: sensitivity analyses
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Ponte della Musica: sensitivity analyses
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On-going work: indicial functions theory
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Indicial functions theory
Linear theory
o Aerodynamic coefficients linearized with respect to the state
variables if their variations are smooth functions of those
states.
o The linear step-change response can be convoluted with the
input to predict the output of a linear system, the nonlinear
indicial theory is a generalization of this concept.
Nonlinear theory
o Linear formalism in the form of a generalized superposition
integral, states evolution depends on the entire history of the
motion.
o The aeroelastic response to an arbitrary input can be
constructed by integrating a nonlinear functional, that
involves the knowledge of the time-dependent input and the
indicial response.
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Indicial functions theory
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Linear/nonlinear indicial functions
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CFD calculations
U wind upstream 8m/s ; Re = 1.65 107
Wide range of CFD
results in literature
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Unsteady aerodynamics lag states
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Numerical approaches
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Summary
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Solar tracker: flutter and passive control
Rome, December, 2009
U=23.65 m/s