Vibration damping performances of buildings with moving façades under harmonic excitation

Façade technologies are in continuous evolution and the idea to realize buildings equipped with cladding systems capable to undergo significant displacements relatively to the main structure has been considered by many authors as an opportunity to improve their vibration performances. From a structural dynamics viewpoint, a building with a monolithic Moving Façade is essentially the same thing as a building with a Tuned Mass Damper. However, in the presence of excitations directly acting on the external surface of the building, there may be significant diferences of behavior. In this work, a first step towards a systematic comparison between the performances of buildings with Moving Façades and Tuned Mass Dampers is carried out in the simplest setting of 2 degrees of freedom modeling and harmonic excitation. Results Despite the deceptive simplicity of the setting, some of the aspects related to the potential applicability of moving façades to vibration damping and the correlated limitations are discussed and critically analyzed. The analyses show that, depending on the tuning of the system, monolithic Moving Façades could effectively act as vibration absorbers with a potentially high efficiency. However, it turns out that good performances could be realized at the price of extremely large displacements of the façade. The possibility to pursue potential applications of this type of systems seems therefore to be subordinated to the search of solutions to limit such displacements within functionally acceptable ranges

A Novel Highly Accurate Finite-Element Family

A novel Nth order finite element for interior acoustics and structural dynamics is presented, with N arbitrarily large. The element is based upon a three-dimensional extension of the Coons patch technique, which combines high-order Lagrange and Hermite interpolation schemes. Numerical applications are presented, which include the evaluation of the natural frequencies and modes of vibration of (1) air inside a cavity (interior acoustics) and (2) finite-thickness beams and plates (structural dynamics). The numerical results presented are assessed through a comparison with analytical and numerical results. They show that the proposed methodology is highly accurate. The main advantages however are (1) its flexibility in obtaining different level of accuracy (p-convergence) simply by increasing the number of nodes, as one would do for h-convergence, (2) the applicability to arbitrarily complex configurations, and (3) the ability to treat beam- and shell-like structures as three-dimensional small-thickness elements

Ilvo Diamanti, Marc Lazar, "Titolo: Popolocrazia. La metamorfosi delle nostre democrazie"

Recensione del volum

Chiara Giorgi, Ilaria Pavan, "Storia dello Stato sociale in Italia"

Recensione del volum

Paolo Pombeni, "L'apertura. L'Italia e il centrosinistra (1953-1963)"

Recensione del volum

George A. Gonzalez, "Titolo: Star Trek and Popular Culture. Television at the Frontier of Social and Political Change in the 1960s"

Recensione del volum