Ricerc@Sapienza

A continuum-based mechanical model describing the nonlinear response of long-span suspension bridges (SB) subjected to wind-induced dynamic forces and including the presence of a novel passive control system is developed to predict and mitigate large-amplitude oscillations arising from aerodynamic instability phenomena. A nonlinear parametric model developed in the past by the Proponent of this project to study aeroelastic instabilities in SB will be the starting point of the proposed research activity. Such mechanical model will be enhanced by including an innovative vibration control system based on tuned mass dampers possessing negative stiffness and hysteretic damping provided by parts made of shape memory alloy (SMA).
This research will lead to an advance in several aspects concerning the control of wind-induced instabilities in long-span suspension bridges and the project will pave the way for the use of novel, non-conventional, control devices based on smart materials possessing strongly nonlinear features.
A parametric tool will be first developed to study the bifurcation scenarios, arising in SB from the wind-structure interaction, by means of advanced analytical and numerical techniques, such as perturbation analyses and numerical continuation. Then, the project will focus on the fine tuning of a novel approach for the control of large-amplitude oscillations in SB through nonlinear passive control devices based on SMA material and possessing negative stiffness. Such unconventional mechanical property will be the key-feature for the control optimization of the SB dynamic response which, as known, is characterized by a strongly nonlinearity of hardening type. Lastly, detailed studies devoted to demonstrate the feasibility of the here proposed novel control system will be carried out after an accurate numerical validation of the model and of the numerical codes; this, will be the starting point for the actual realization of the device in the next future.