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Baratta, A.; Cennamo, C.; Voiello, G.
doi: 10.1002/stc.4300050202pmid: N/A
The object of the research is the design procedure of a linear control algorithm able to mitigate the effects of seismic shaking as far as possible, maintaining the running and installation costs within admissible bounds. The procedure starts from approaching the solution of the equation of motion of a SDOF structure in the norm sense, as explained in Secs. 2–3, which allows to obtain results that do not depend on the details of the forcing function. The approach is generalized to MDOF structures by modal decomposition, and it is shown that the control algorithm can be designed by independent modal control, by applying at each mode the procedure outlined for a SDOF system. Robustness of the algorithm with reference to uncertain identification of the structural properties is successfully investigated, both by theoretical tools and by numerical simulation. The whole pattern proves to be effective and poorly conditioned by the peculiar characters of the excitation.
Casciati, F.; Faravelli, L.; Petrini, L.
doi: 10.1002/stc.4300050203pmid: N/A
A large worldwide earthquake data‐bank is available for numerical and experimental response analyses of base‐excited structural systems. Most of these accelerograms are stored in their uncorrected form and this is appropriate and convenient since they must be differently processed for different engineering applications. Record processing is a necessary step toward the use of recorded data in numerical simulations: it deletes spurious low and high frequency content, introduced in detection, acquisition, storage and digitalization of the signal. Moving from numerical to experimental analyses, the testing machine acts as a filter and, hence, the processing could be no longer required. The paper tries to investigate this aspect.
doi: 10.1002/stc.4300050204pmid: N/A
We show that the electromechanical coupling factor is the solution of two eigenvalue problems which depends on the piezoelectric, elastic and dielectric properties of the materials. We show that there are at most three eigenvalues and three associated strain eigentensors which render extremum the ratio of mechanical energy converted into electric energy: their value is the same if the three eigenvalues whose associated electric field eigenvectors render extremum the ratio of electrical energy converted into mechanical.
Nicotra, V.; Podio‐Guidugli, P.
doi: 10.1002/stc.4300050205pmid: N/A
A linear theory of electroelastic plates capable of thickness changes is presented. It is shown that, for transversely isotropic plates, the general boundary‐value problem decouples into a membrane problem and a flexure problem; in each subproblem, piezoelectric and electrostrictive effects are in order, with peculiar forms. An example is studied, where thickness changes in membrane regime are induced either by mechanical loads or by electric loads.
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