Ricerc@Sapienza

Characterization of the dynamic behavior of linear systems is exhaustively described with a single frequency response curve (frc). For nonlinear systems, which tend to depend on load amplitude, at least one frc for each excitation intensity is required to detect the main characteristics of the dynamic response. Nonlinear systems, more commonly dealt with in the literature, are invariant with respect to the deformation history and, thus, frcs obtained with increasing and decreasing driving frequency coincide, apart from the frequency range with coexistent solutions.

The high socio-economic impacts of moderate-to-strong earthquakes in terms of damage, dollars and downtime have highlighted the great divergence between societal expectations and the reality of modern building seismic performance. Community strongly requires raising the bar of the current seismic design philosophy, that conceives structures as ductile systems where inelasticity is concentrated within plastic hinge regions. Well complying with these methodologies many modern buildings have behaved as expected in recent earthquakes, however in many cases they were severely damaged.

Lessons from recent earthquakes have provided a tough reality check of the current seismic design approach,
highlighting a critical mismatch between societal expectations over the reality of seismic performance of modern
buildings. The performance-based design criteria and objectives need a paradigm shift towards low-damage design
philosophy and technologies that should The project provided the opportunity to coordinate a unique research effort for
the development and possible future implementation in the European Environment of an integrated low-damage

The increasing demand for miniaturized radio-controlled vehicles inspired the following research. The uses of these unmanned miniaturized/micro vehicles range from aero-modeling to drones for urban control and military applications too. The common characteristic of these vehicles is the need for a light and compact propulsion system. The radio-controlled (RC) turbines for modeling are ideally suited for this purpose, guaranteeing the necessary thrust with compactness and lightness.

We present a study of wave overtopping of barriers. The phenomenon of the wave overtopping over emerged structures is reproduced both numerically and experimentally. The numerical simulations are carried out by a numerical scheme for three-dimensional free-surface flows, which is based on the solution of the Navier-Stokes equations in a novel integral form on a time-dependent coordinate system. In the adopted numerical scheme, a novel wet-dry technique, based on the exact solution of the Riemann problem over the dry bed, is proposed.

Control and inspection of the conditions of elastomeric bearings used for seismic isolation purpose is a fundamental activity in ensuring and preserving the performance of a structure. The methods currently used, such as visual inspections, Operational Modal Analysis (OMA), release tests, very often present strong limitations due to their qualitative nature or else to the costs associated with their implementation and functioning. An innovative procedure based on the use of nanoindentation tests is proposed and validated through an experimental campaign.