1,721,008 research outputs found
Innovative Structures for Lightweight Vehicles
No full textThis volume collects the lecture notes of the Advanced Webiner on Innovative Structures for Lightweight Vehicles, which brought together experts in the fields of structural modelling, composite materials, nano-materials, and smart structures for vibration control. The course combined the academic scientific excellence with industrially-relevant applications and was organized by the partners of the on-going intersectorial MIUR PRIN project DEVISU: DEvelopment and applications of a VIrtual hybrid platform for multiscale analysis of advanced StructUres of aircraft. The course was organised in six sessions and they are briefly detailed in the following.
The first Part considers the development of the Carrera Unified Formulation (CUF) as a tool to develop 2nd generation of theories of structures, including beams, plates and shells. In the first part, enhanced 1D and 2D formulations are presented with reference to the condensed CUF notation and using the so-called equivalent-single-layer, zig-zag and layer-wise theories. In the second part, asymptotic and axiomatic approaches are compared, which lead to the Best Theory Diagram using genetic-type algorithms rotating blades and rotor-dynamic analysis, applications to bio-structures and fluid dynamics of Poiseuille flow with Stokes fluid flux.
The second Part is focussed on design and optimization of new, disruptive structural solutions for aerospace systems. Initially the focus is on the extension of CUF to geometrical nonlinear problems. Then, the stiffness tailoring of variable stiffness laminates is examined, considering curvilinear stiffeners too. Finally aerodynamic and aeroelastic preliminary design tools and theoretical frameworks are introduced, which are customized for innovative non planar wing systems.
The third Part aims at introducing new trends in multi-scale and coupled computational mechanics. The main aspects are first discussed for a recently developed three-dimensional computational framework for multiscale and multi-physics analysis of structures made of polycrystalline materials. Then, the solution of discontinuous mechanical problems by Peridynamics, which is a non-local continuum theory based on integral equations, are presented. Finally, variable kinematics (eventually multi-dimensional) models for the analysis of multi-component structures and local-nonlocal material subdomains are revised using CUF.
The fourth Part concerns a presentation of a range of activities focused on similitudes in vibroacoustics. The main rules for building complete or distorted/incomplete models will be presented and discussed with theoretical, numerical and experimental investigations. Specific attention will be paid also to the structural and the aero/acoustic responses. The approach will be presented by using all the available information coming from analytical developments, numerical investigations and experimental tests.
Also emphasis will be given to the adoption of Machine Learning to support the analysis and the definition of the scaling laws for mechanical systems.
The fifth Part provides a comprehensive overview of the principal features of smart thin structures equipped with feed-forward and feedback systems for the control of the flexural response and sound transmission due respectively to tonal and to stochastic broadband disturbances. The Session is structured in 3 Parts. Part 1, presents an overview of the excitation, flexural response and sound radiation of thin structures exposed either to deterministic (e.g. plane acoustic waves) and stochastic (e.g. acoustic diffuse field and turbulent boundary layer) excitations. The second part introduces and discussed the physical effects of a single channel and multi-channel feed-forward and feedback control systems. Finally the third part presents an overview of practical smart structures.
The sixth Part is dedicated to: i) a general presentation of an Aeroelastic Tailoring Methodology, ii) its application to develop adequate margins in buckling of wing panels, iii) the use of lightweight composites as substitutes to die forgings in aircraft structures like la nding gears.
The first part discusses the Aeroelastic Tailoring methodology, which is used to design wing structures to meet strength, buckling and flutter requirements simultaneously. The second part presents an application of the Aeroelastic Tailoring in typical composite wing panels to study the effect of pure compression loads and develop adequate margins in buckling. Finally, the third part discusses the design of composite complex shaped components as replacement of parts made with metal forgings is introduced
Innovative Structures for Lightweight Vehicles
No full textThis volume collects the lecture notes of the Advanced Webiner on Innovative Structures for Lightweight Vehicles, which brought together experts in the fields of structural modelling, composite materials, nano-materials, and smart structures for vibration control. The course combined the academic scientific excellence with industrially-relevant applications and was organized by the partners of the on-going intersectorial MIUR PRIN project DEVISU: DEvelopment and applications of a VIrtual hybrid platform for multiscale analysis of advanced StructUres of aircraft. The course was organised in six sessions and they are briefly detailed in the following.
The first Part considers the development of the Carrera Unified Formulation (CUF) as a tool to develop 2nd generation of theories of structures, including beams, plates and shells. In the first part, enhanced 1D and 2D formulations are presented with reference to the condensed CUF notation and using the so-called equivalent-single-layer, zig-zag and layer-wise theories. In the second part, asymptotic and axiomatic approaches are compared, which lead to the Best Theory Diagram using genetic-type algorithms rotating blades and rotor-dynamic analysis, applications to bio-structures and fluid dynamics of Poiseuille flow with Stokes fluid flux.
The second Part is focussed on design and optimization of new, disruptive structural solutions for aerospace systems. Initially the focus is on the extension of CUF to geometrical nonlinear problems. Then, the stiffness tailoring of variable stiffness laminates is examined, considering curvilinear stiffeners too. Finally aerodynamic and aeroelastic preliminary design tools and theoretical frameworks are introduced, which are customized for innovative non planar wing systems.
The third Part aims at introducing new trends in multi-scale and coupled computational mechanics. The main aspects are first discussed for a recently developed three-dimensional computational framework for multiscale and multi-physics analysis of structures made of polycrystalline materials. Then, the solution of discontinuous mechanical problems by Peridynamics, which is a non-local continuum theory based on integral equations, are presented. Finally, variable kinematics (eventually multi-dimensional) models for the analysis of multi-component structures and local-nonlocal material subdomains are revised using CUF.
The fourth Part concerns a presentation of a range of activities focused on similitudes in vibroacoustics. The main rules for building complete or distorted/incomplete models will be presented and discussed with theoretical, numerical and experimental investigations. Specific attention will be paid also to the structural and the aero/acoustic responses. The approach will be presented by using all the available information coming from analytical developments, numerical investigations and experimental tests.
Also emphasis will be given to the adoption of Machine Learning to support the analysis and the definition of the scaling laws for mechanical systems.
The fifth Part provides a comprehensive overview of the principal features of smart thin structures equipped with feed-forward and feedback systems for the control of the flexural response and sound transmission due respectively to tonal and to stochastic broadband disturbances. The Session is structured in 3 Parts. Part 1, presents an overview of the excitation, flexural response and sound radiation of thin structures exposed either to deterministic (e.g. plane acoustic waves) and stochastic (e.g. acoustic diffuse field and turbulent boundary layer) excitations. The second part introduces and discussed the physical effects of a single channel and multi-channel feed-forward and feedback control systems. Finally the third part presents an overview of practical smart structures.
The sixth Part is dedicated to: i) a general presentation of an Aeroelastic Tailoring Methodology, ii) its application to develop adequate margins in buckling of wing panels, iii) the use of lightweight composites as substitutes to die forgings in aircraft structures like la nding gears.
The first part discusses the Aeroelastic Tailoring methodology, which is used to design wing structures to meet strength, buckling and flutter requirements simultaneously. The second part presents an application of the Aeroelastic Tailoring in typical composite wing panels to study the effect of pure compression loads and develop adequate margins in buckling. Finally, the third part discusses the design of composite complex shaped components as replacement of parts made with metal forgings is introduced
Active vibroacoustic control
No full textContentsAn Introduction to Active Vibration Control; A. Preumont.
Active Sound Control; S.J. Elliott.
Active Vibro Acoustic Control; S.J. Elliott, P. Gardonio.
Actuators and Sensors in Structural Dynamics; W. Gawronski.
Robust Control of Vibrating Structures; K.B. Lim.
Finite Element Models for Piezoelectric Continua; P. Gaudenzi.
Latest Trends in the Development of Piezoelectric Multi-degree-of-freedom Actuators/Sensors; R. Bansevicius.
Damping Control in Systems Assembled by Semi-Active Joints; R. Nitsche, L. Gaul.
Piezoelectric Stack Actuator: FE-Modeling and Application for Vibration Isolation; U. Stöbener, L. Gaul.
Active Vibration Control of a Car Body Based on Experimentally Evaluated Modal Parameters; U. Stöbener, L. Gaul.
PVDF-Transducers for Structural Health Monitoring; S. Hurlebaus, L. Gaul.
Vibro-Isolation of Sensitive Equipment; V. Ostasevicius.
An Approach to Smart Structure Design using MEMS Technology; P. Minotti.
Power Amplifiers for Piezoelectric Actuators; H. Janocha, et al
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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