SISO Piezo based circuit development for active structural vibration control

This 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

Vibration parameters for impact detection of composite panel: A neural network based approach

The 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

Bridging Theatre, School, Business, and Literacy: Discovering Creativity through Theatre Exercises

For too long, our careerist focus in elementary school, secondary school, and higher education has marginalized the arts, particularly theatre, suggesting that theatre is non-essential to educational, particularly SUNY, intent. However, recent cross-disciplinary research, such as that presented by Vera & Crossan (2005) in Organization Science, asserts the structure by which principles of improvisational theatre (e.g. collaboration, agreeing-accepting-adding, being present in the moment) help those in business rethinking team work. Further Richards (2012) in International Journal Of Market Research writes about using creative (theatre-based) workshops as data-generation research tools to discover things about the way consumers behave, in order to rethink marketing . Additionally, through improv and acting, we have the means to bridge students to active reading, to fight tangible trends toward lower literacy. My past work with children, and my current research into adapting and applying theatre theory, as well as methodology, to business models will background my presentation of a few exercises in improvisation and articulating intentionality, so that attendees will leave with a recognition of the enhancement theatre exercises bring to (a) active listening, (b) attentiveness to/awareness of one’s surroundings and what is taking place in them. Attendees will also leave with specific verbal and physical exercises/tools with which to ignite imagination, remove inhibitions to creative thinking, and bridge business with the arts

Strain state detection in composite structures: Review and new challenges

Developing 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

Preface to the Special Issue on the New Frontiers of Acoustic Modeling and Optimization

The 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

Constitutional Law - Fourteenth Amendment - Due Process - Civil Commitment - Mentally Ill and Retarded Juveniles

The United States Supreme Court has upheld the constitutionality of Pennsylvania\u27s voluntary admission and commitment procedures for mentally ill or retarded juveniles, which provide for determination by a neutral fact finder of the necessity for confinement and periodic review of the necessity for continued confinement by a similar procedure. Secretary of Public Welfare v. Institutionalized Juveniles, 442 U.S. 640 (1979)

AN INNOVATIVE VISCOELASTIC TREATMENT FOR THE INTERNAL NOISE REDUCTION IN A REGIONAL AIRCRAFT

The improvement of interior comfort is becoming an increasingly required target in the transport engineering field, with particular attention to the aviation one. Generally, an aircraft is affected by several noise sources, from the engine power unit to the broadband components, related to the turbulent boundary layer (TBL). In this contest, the leading industries, in cooperation with research centers and universities, are actually employed in the development of innovative passive/active solutions for the internal noise as well as vibrations control: such technological implications must, on the one hand, satisfy these design requirements as well as meet the current airworthiness regulations. The paper deals with the vibro-acoustic testing activity on a typical turboprop fuselage subjected to different external load conditions: the damping ratio and the transmission loss characterization has been performed for several materials, including two innovative viscoelastic treatments too. The results highlighted a very good behaviour of the novel viscoelastic foams in terms of both acoustic and thermal performance when compared to standard blanket supported by extra viscoelastic treatments offering a very interesting self-embedded solution with a good weight to performance ratio

Improving operation of a complex headworks system for municipal use and hydropower production by mathematical programming

The paper presents a Mixed Integer Non Linear Programming (MINLP) model of the water resources system supplying Genoa, in northern Italy. The system presently features five reservoirs, three main river intakes, and two well fields. The hydrological regime is typically Mediterranean; water availability is however relatively abundant, so that drought issues are limited, especially now that water demand from the supply sources has decreased due to reduced population, deindustrialization and to improvement in the operation and maintenance of the water distribution network. In this context, it is worthwhile considering the possibility to relax an over-conservative management of resources, justified by the experience of previous drought events, and to explore the viability of exploiting resources from reservoirs for hydropower production. The MINLP model expresses cost minimization over a 40 year time period on a monthly basis, subject to physical constraints. Costs include scarcity costs (the economic value of possible water deficits) and extraction costs from wells, minus hydropower production. The model has been written in GAMS and solved through the SBB (Simple Branch and Bound) solver. Results show that the system is able to meet demand over the 40 year hydrologic scenario with negligible water deficits and that hydropower production may be enhanced compared to present by increasing releases from reservoirs, which ultimately implies accepting keeping reservoirs emptier than presently done

Digital holographic interferometry for particle detector diagnostic

In high precision scattering experiments particle tracks must often be reconstructed from a series of hits in successive detector planes. The relative distance between these planes is a critical parameter that must be monitored during operation. To address this problem we have developed a digital holographic interferometer dubbed Holographic Alignment Monitor (HAM) to be used in the MUonE project at CERN. MUonE aims at a precision measurement of the scattering angle between particles after an elastic muon-electron scattering. The HAM is designed to monitor the relative distance between position-sensitive sensor planes inside a MUonE tracking station with a resolution better than the required 10 m. The system uses a 532 nm fiber-coupled laser source both to illuminate a portion of the detector plane (object), and to provide the reference beam. A CMOS image sensor acquires the raw data, and the reconstructed holographic image of the silicon sensor being observed is computed using an algorithm containing a Fourier transform. The relative distance between silicon planes is monitored by superposing successive raw images of the same object on an initial reference one and observing the interference fringes appearing on the reconstructed holographic image. Preliminary tests have yielded a distance resolution of less than 1 m