1,720,982 research outputs found
A Damage Identification procedure based on Hilbert transform: experimental validation
Full text linkThis paper aims at validating the feasibility of an identification procedure, based on the use of the Hilbert
transform, by means of experimental tests for shear-type multi-degree-of-freedom systems. Particularly,
a three-degree-of-freedom frame will be studied either numerically or experimentally by means of
a laboratory scale model built at the laboratory of the Structural, Aerospace and Geotechnical Engineering
Department (DISAG) of University of Palermo. Several damage scenarios have been considered to prove
the effectiveness of the procedure. Moreover, the experimental tests have been conducted by considering
two different input loads: pulse forces, simulated by means of an instrumental hammer, and wide band
noise base inputs, by a shake table.
In the first section the damage identification procedure, proposed in recent works, is presented. The
procedure is based on the minimization of an objective function mathematically based on the properties of
the analytical signal and the Hilbert transform. Second section reports the experimental model geometrical
data and the data acquisition set-up as built in the DISAG laboratory. In Section 3, the results of the
experimental campaigns are presented and discussed having considered three damage scenarios. The
validated procedure has been proved to be able to not only detect damage even at early stage but it also needs
processing of only few samples of the structural respons
Innovative modeling of Tuned Liquid Column Damper motion
No full textIn this paper a new model for the liquid motion within a Tuned Liquid Column Damper (TLCD) device is developed, based on the mathematical tool of fractional calculus. Although the increasing use of these devices for structural vibration control, it is shown that existing model does not always lead to accurate prediction of the liquid motion. A better model is then needed for accurate simulation of the behavior of TLCD systems. As regards, it has been demonstrated how correctly including the first linear liquid sloshing mode, through the equivalent mechanical analogy well established in literature, produces numerical results that highly match the corresponding experimental ones. Since the apparent effect of sloshing is the deviation of the natural frequency from the theoretical one, the authors propose a fractional differential equation of motion. The latter choice is supported by the fact that the introduction a fractional derivative of order α alters simultaneously both the resonant frequency and the degree of damping of the system. It will be shown, through an extensive experimental analysis, how the proposed model accurately describes liquid surface displacements
Optimal tuning of tuned liquid column damper systems in random vibration by means of an approximate formulation
No full textL’identificazione Dinamica Delle Caratteristiche Modali E Meccaniche Della Struttura Della Cupola Del Teatro Massimo
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Direct evaluation of the equivalent linear damping for Tuned Liquid Column Damper systems in random vibration for pre-design purposes
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