1,721,390 research outputs found
SISO Piezo based circuit development for active structural vibration control
Full text linkThis paper deals with the issue of developing a smart vibration control platform following an innovative model‐based approach. As a matter of fact, obtaining accurate information on system response in pre‐design and design phases may reduce both computational and experimental efforts. From this perspective, a multi‐degree‐of‐freedom (MDOF) electro‐mechanical coupled system has been numerically schematized implementing a finite element formulation: a robust simulation tool integrating finite element model (FEM) features with Simulink® capabilities has been developed. Piezo strain actuation has been modelled with a 2D finite element description: the effects exerted on the structure (converse effect) have been applied as lumped loads at the piezo nodes interface. The sensing (direct effect) has instead been modelled with a 2D piezoelectric constitutive equation and experimentally validated as well. The theoretical study led to the practical development of an integrated circuit which allowed for assessing the vibration control performance. The analysis of critical parameters, description of integrated numerical models, and a discussion of experimental results are addressed step by step to get a global overview of the engineering process. The single mode control has been experimentally validated for a simple benchmark like an aluminum cantilevered beam. The piezo sensor‐actuator collocated couple has been placed according to an optimization process based on the maximum stored electrical energy. Finally, a good level of correlation has been observed between the forecasting model and the experimental application: the frequency analysis allowed for characterizing the piezo couple behavior even far from the resonance peak
Strain state detection in composite structures: Review and new challenges
Full text linkDeveloping an advanced monitoring system for strain measurements on structural components represents a significant task, both in relation to testing of in-service parameters and early identification of structural problems. This paper aims to provide a state-of-the-art review on strain detection techniques in composite structures. The review represented a good opportunity for direct comparison of different novel strain measurement techniques. Fibers Bragg grating (FBG) was discussed as well as non-contact techniques together with semiconductor strain gauges (SGs), specifically infrared (IR) thermography and the digital image correlation (DIC) applied in order to detect strain and failure growth during the tests. The challenges of the research community are finally discussed by opening the current scenario to new objectives and industrial applications
Vibration parameters for impact detection of composite panel: A neural network based approach
Full text linkThe need for reliable methodologies for structural monitoring is certainly a current line of research in many engineering sectors. The detection of the impact on composite materials is in fact a recent subject of study, aimed at safeguarding the mechanical integrity and improving the useful life of structural components. In such a context, the work deals with evaluation of the use of neural algorithms for localizing the position of the impacts on composite structures. Starting from FE (finite element) simulations, representative of the dynamic response of a CFRP (Carbon Fiber Reinforced Polymer) panel as a benchmark, the approach has been finally validated experimentally by modal parameters identification
Preface to the Special Issue on the New Frontiers of Acoustic Modeling and Optimization
Full text linkThe field of acoustics involves the study of sound propagation, both in free and closed
environments, through the development of both forecasting simulations and experimental
techniques [1–8]. Currently, such science finds its applications covering several engineering
sectors, especially when it is necessary to evaluate the sound response in mid- and high frequency ranges. The purpose of acoustic modeling is to design “systems” (aeronautical,
buildings, engines, electronic, etc.) that are more comfortable and functionally more
efficient. From this perspective, the development of effective tools for acoustic prediction
and optimization is a challenge for the research community, as the qualification processes
need to be streamlined to reduce high computational/testing efforts. The main issues of
theoretical modeling include the discretization of disturbance sources, stochastic signal
processing, active/passive noise control studies, the optimization of genetic algorithms,
and neural network implementation, which are among the most interesting topics yet
to be covered in-depth. For this Special Issue (belonging to the section “Acoustics and
Vibrations”), the Editors encourage the submission of novel contributions (papers, technical
reports, and broad reviews) from members of the technical-scientific community involved
in the advancement of predictive methods and in the study of solutions aimed at noise
identification/optimization. This initiative will help readers understand various acoustic
modeling issues with comprehensive details. Research methods can include numerical
validations, experimental studies, and the development of new certification standards,
presenting the state-of-the-art results that will have a significant impact on academic interest
and industrial growth. Potential future directions could be presented, relying on advanced
trends, but also on existing research limitations
Integrazione di energie rinnovabili negli spazi aperti della città consolidata
No full textLa diffusione delle tecnologie da f.e.r. attraverso processi di integrazione all'ambiente costruito nel territorio italiano, caratterizzato da un'elevata diffusione di centri urbani e di paesaggi di antica formazione e comunque di interesse culturale ed ambientale, fa i conti con vincoli complessi derivanti dalla molteplicità di attori, obiettivi e valori coinvolti. In particolare, per i contesti insediativi "sensibili” (nuclei storici, aree di interesse naturalistico/ambientale, comunque soggette a vincoli ambientali ecc.) si avverte l’esigenza di promuovere ricerche e riflessioni sul rapporto tra tecnologie disponibili e in fase di sviluppo e contesti locali transcalari (dall'edificio all'insediamento).
A tutti i livelli d’intervento e nelle diverse fasi della decisione appare necessario superare una logica basata esclusivamente su requisiti tecno-energetici e sviluppare modalità di approccio di tipo sistemico che facciano riferimento anche ai valori culturali dell'ambiente fisico (paesaggi insediativi), a metodi di analisi, valutazione e previsione delle trasformazioni dei processi edilizi, e ai contributi normativi e di processo virtuosi che caratterizzano le "best practice
Riqualificazione architettonica e ambientale di aree complesse in contesti mediterranei - Architectural and environmental rehabilitation of complex areas in the Mediterranean context
No full textFiumare di Messina: un’identità territoriale negata da recuperare
No full textMessina è una “terra di mezzo” che, a dispetto della sua geografia di transizione, ha un carattere forte e autonomo, con i suoi territori densamente urbanizzati e al contempo con aree ancora naturali e selvagge. È un territorio con pesanti placche edificate contrapposte a borghi isolati e prossimi all’abbandono, piccoli centri urbani arroccati sui colli aspri, resilienti alla marginalità e alla fragilità dei terreni. Le fiumare, rappresentano uno degli elementi contraddistintivi del paesaggio messinese. Trascurati negli anni del grande sviluppo urbanistico, i fiumi oggi reclamano il loro spazio con le loro rovinose piene. Le calamità diventano sempre più frequenti, causate da precipitazioni abbondanti e improvvise, i cui effetti vengono aggravati da un disboscamento secolare; dall’abbandono dei territori rurali e dal degrado dei terrazzamenti. In questo scenario di spettacolare bellezza naturale, solo l’urbanizzazione sciatta e disordinata mostra piena omogeneità, avendo investito entrambe le rive dello Stretto senza alcuna preoccupazione né per i disastri naturali (che hanno contrassegnato la storia millenaria di questo sistema) né per il paesaggio naturale a tratti cancellato dalla pressione speculativa degli ultimi decenni e dal banale e dissennato consumo di territorio
Unità tecnologiche complesse e integrate per la riqualificazione del Circolo dei Forestieri in piazza Schettini
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