Banco Tensore d'Inerzia

Nella presente relazione si descrive il Banco Tensore d'Inerzia realizzato presso il Dipartimento al fine di soddisfare la richiesta, avanzata in particolar modo dalle aziende del settore automotive, di disporre della misura dei parametri d'inerzia di interi veicoli o di suoi componenti. Dopo aver descritto il principio di funzionamento, si illustreranno le procedure di prova e le tecniche adottate per la calibrazione

Analysis and design of passive and active microstrip reflectarrays

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Le attività del gruppo operativo INGV "SISMIKO" durante la sequenza sismica "Amatrice 2016",

SISMIKO è un gruppo operativo dell’Istituto Nazionale di Geofisica e Vulcanologia (INGV) che coordina tutte le Reti Sismiche Mobili INGVPublishedLecce3T. Sorgente sismica4T. Sismicità dell'Italia8T. Sismologia in tempo reale1SR TERREMOTI - Sorveglianza Sismica e Allerta Tsunami2SR TERREMOTI - Gestione delle emergenze sismiche e da maremoto3SR TERREMOTI - Attività dei Centr

SISMIKO:emergency network deployment and data sharing for the 2016 central Italy seismic sequence

At 01:36 UTC (03:36 local time) on August 24th 2016, an earthquake Mw 6.0 struck an extensive sector of the central Apennines (coordinates: latitude 42.70° N, longitude 13.23° E, 8.0 km depth). The earthquake caused about 300 casualties and severe damage to the historical buildings and economic activity in an area located near the borders of the Umbria, Lazio, Abruzzo and Marche regions. The Istituto Nazionale di Geofisica e Vulcanologia (INGV) located in few minutes the hypocenter near Accumoli, a small town in the province of Rieti. In the hours after the quake, dozens of events were recorded by the National Seismic Network (Rete Sismica Nazionale, RSN) of the INGV, many of which had a ML > 3.0. The density and coverage of the RSN in the epicentral area meant the epicenter and magnitude of the main event and subsequent shocks that followed it in the early hours of the seismic sequence were well constrained. However, in order to better constrain the localizations of the aftershock hypocenters, especially the depths, a denser seismic monitoring network was needed. Just after the mainshock, SISMIKO, the coordinating body of the emergency seismic network at INGV, was activated in order to install a temporary seismic network integrated with the existing permanent network in the epicentral area. From August the 24th to the 30th, SISMIKO deployed eighteen seismic stations, generally six components (equipped with both velocimeter and accelerometer), with thirteen of the seismic station transmitting in real-time to the INGV seismic monitoring room in Rome. The design and geometry of the temporary network was decided in consolation with other groups who were deploying seismic stations in the region, namely EMERSITO (a group studying site-effects), and the emergency Italian strong motion network (RAN) managed by the National Civil Protection Department (DPC). Further 25 BB temporary seismic stations were deployed by colleagues of the British Geological Survey (BGS) and the School of Geosciences, University of Edinburgh in collaboration with INGV. All data acquired from SISMIKO stations, are quickly available at the European Integrated Data Archive (EIDA). The data acquired by the SISMIKO stations were included in the preliminary analysis that was performed by the Bollettino Sismico Italiano (BSI), the Centro Nazionale Terremoti (CNT) staff working in Ancona, and the INGV-MI, described below

Sphere rolling on a moving surface: Application of the fundamentalequation of constrained motion

This paper deals with the general formulation of the problem of a rigid sphere rolling under gravity on an arbitrarily prescribed surface that is moving in an arbitrarily prescribed manner. This is accomplished by using a recently developed modeling paradigm, which is encapsulated in a systematic general three-step procedure. The first step develops the equations of motion of the so-called unconstrained system in which the sphere is decoupled from the surface on which it moves. The novelty in this paper is the inclusion of a zero-mass particle and its associated coordinates in the unconstrained description of the system, whose equations of are trivial to write down since it is assumed that all the coordinates are independent of one another. However, this leads to a singular mass matrix. The second step involves the statement of the constraints that (a) cause the sphere to roll on the surface without slip, (b) cause the zero-mass particle to bind to the surface and to become the point of contact between the sphere and the surface, and (c) ensure that the quaternion describing the rotational motion of the sphere is a unit quaternion. The third step involves the direct application of the Udwadia–Phohomsiri equation that generates the equations of motion for the system. Simulations of the motion of a sphere rolling on a moving parabolic surface are shown illustrating the ease and efficacy with which both the formulation and the numerical results can be obtained. The systematic modeling procedure used here to study the dynamics of the rolling sphere along with the use of a zero-mass particle opens up new ways for modeling and simulating the dynamical behavior of complex multi-body systems

Investigation on the mechanical properties of MRE compounds

This paper describes an experimental investigation conducted on magneto-rheological elastomers (MREs) with the aim of adopting these materials to make mounts to be used as vibration isolators. These materials, consisting of an elastomeric matrix containing ferromagnetic particles, are considered to be smart materials, as it is possible to control their mechanical properties by means of an applied magnetic field. In the first part of the paper, the criteria adopted to define the characteristics of the material and the experimental procedures for making samples are described. The samples are subjected to a compressive static test and are then, adopting a testing machine specially configured, tested for shear periodic loads, each characterized by a different constant compressive preload. The testing machine is equipped with a coil, with which it is possible to vary the intensity of the magnetic field crossing the sample during testing to evaluate the magneto-rheological effect on the materials’ characteristics in terms of stiffness and damping

A seismic insulator based on wire rope spring and BTU

Seismic insulators must have low horizontal stiffness values so that the fundamental period of the suspended mass is well above the predominant period of the earthquake and high vertical stiffness values to limit the vertical deflection caused by the weight of the suspended mass. Wire rope springs do not have this feature but they can operate as seismic insulators if used in parallel with a device that is capable of bearing the supported equipment weight and allows it to move in any horizontal direction with low friction. With this aim, the results of tests conducted on a seismic insulator prototype comprising a wire rope spring and a ball transfer unit (BTU) are reported in this paper