Teoria dei sistemi. Esercizi d'esame PDF Download

Author: Stefano Battilotti
Publisher:
ISBN: 9788880661474
Category : Mathematics
Languages : it
Pages : 160

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Author: Umberto Soverini
Publisher: Società Editrice Esculapio
ISBN:
Category : Science
Languages : it
Pages : 176

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Numerosi fenomeni nelle scienze e nell’ingegneria si prestano ad una accurata descrizione in termini di equazioni differenziali e alle differenze. A tale proposito la Teoria dei Sistemi Dinamici costituisce un utile strumento metodologico per affrontare e risolvere problemi di analisi e sintesi, a prescindere dalla natura specifica del fenomeno sotto osservazione. Il libro raccoglie, suddivisi in quattro capitoli, novanta esercizi con soluzione e commento, allo scopo di studiare le proprietà di base dei sistemi dinamici. Vengono considerati sistemi sia a tempo continuo sia a tempo discreto. In particolare, con riferimento ai sistemi dinamici lineari e stazionari, si esaminano in dettaglio le proprietà della matrice di transizione dello stato, essenziali per lo studio della stabilità del sistema. Inoltre, vengono illustrati i legami che intercorrono tra il modello ingresso–stato–uscita del sistema, nel dominio del tempo, e la sua funzione di trasferimento. Al termine, per riassumere le proprietà studiate nei precedenti capitoli, viene proposta una ulteriore raccolta di trenta esercizi, forniti di risposta.

Author: Stefano Battilotti
Publisher: Società Editrice Esculapio
ISBN: 8834153871
Category : Technology & Engineering
Languages : en
Pages : 295

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These notes illustrate the basic elements for analysis and design of linear control systems. With 15 chapters and an appendix of 4 sections the notes start from the notion of mathematical model (system), explaining its important role in the study of a phenomenon and how linear models can arise in practice. Through the time and Laplace analysis the behaviour of a linear model is studied in detail.The basic notions of stability, steady-state and transient response and structural properties give a deep insight in the study of the behavior of an abstract model.In this first part of the notes, the emphasis has been put on the analysis of the properties of a linear system. In the second part of these notes the basic model interconnections are studied, in particular the feedback interconnection and its importance in the design of control systems. Different design methodologies (dynamics assignment, root locus, tracking and disturbance compensation) are illustrated in detail with the support of useful criteria (Nyquist criterion, Routh table) and mathematical tools. In the appendix the necessary mathematical tools are reviewed. The arguments are supported by many examples and figures.

Author: Salvatore Monaco
Publisher: Società Editrice Esculapio
ISBN:
Category : Technology & Engineering
Languages : it
Pages : 418

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Quali sono i fondamenti teorici che sono alla base del comportamento dei sistemi complessi? Come comprendere e valutare le prestazioni di un sistema che si comporta in maniera autonoma? La Teoria dei Sistemi ci introduce alla comprensione dei paradigmi e dei concetti che popolano il sorprendente mondo dell’Automatica. Dopo una breve introduzione destinata ad illustrare in modo succinto il punto di vista dell’Automatica, viene presentata la classe di modelli che sono oggetto di studio: si tratta delle rappresentazioni con lo stato lineari, stazionarie a dimensione finita, sia a tempo continuo che discreto. Lo studio nel dominio del tempo e della variabile complessa, sino alla caratterizzazione del comportamento in frequenza consente di mettere in evidenza i riscontri applicativi ai risultati teorici. Lo studio della stabilità interna ed esterna, delle proprietà dello spazio di stato, dei modelli dei sistemi interconnessi e delle loro proprietà in relazione a quelle dei componenti, sono i tasselli di un mosaico dei metodi fondamentali che vengono illustrati. La loro utilità nella valutazione delle prestazioni e nel progetto dei sistemi di controllo viene messa in luce nell’ultimo capitolo dove viene studiato il problema della modifica della dinamica con controreazione dall’uscita.

Author: Ettore Fornasini
Publisher:
ISBN:
Category :
Languages : it
Pages : 336

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Author: Francesco Tornabene
Publisher: Società Editrice Esculapio
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 689

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The main aim of this book is to analyze the mathematical fundamentals and the main features of the Generalized Differential Quadrature (GDQ) and Generalized Integral Quadrature (GIQ) techniques. Furthermore, another interesting aim of the present book is to shown that from the two numerical techniques mentioned above it is possible to derive two different approaches such as the Strong and Weak Finite Element Methods (SFEM and WFEM), that will be used to solve various structural problems and arbitrarily shaped structures. A general approach to the Differential Quadrature is proposed. The weighting coefficients for different basis functions and grid distributions are determined. Furthermore, the expressions of the principal approximating polynomials and grid distributions, available in the literature, are shown. Besides the classic orthogonal polynomials, a new class of basis functions, which depend on the radial distance between the discretization points, is presented. They are known as Radial Basis Functions (or RBFs). The general expressions for the derivative evaluation can be utilized in the local form to reduce the computational cost. From this concept the Local Generalized Differential Quadrature (LGDQ) method is derived. The Generalized Integral Quadrature (GIQ) technique can be used employing several basis functions, without any restriction on the point distributions for the given definition domain. To better underline these concepts some classical numerical integration schemes are reported, such as the trapezoidal rule or the Simpson method. An alternative approach based on Taylor series is also illustrated to approximate integrals. This technique is named as Generalized Taylor-based Integral Quadrature (GTIQ) method. The major structural theories for the analysis of the mechanical behavior of various structures are presented in depth in the book. In particular, the strong and weak formulations of the corresponding governing equations are discussed and illustrated. Generally speaking, two formulations of the same system of governing equations can be developed, which are respectively the strong and weak (or variational) formulations. Once the governing equations that rule a generic structural problem are obtained, together with the corresponding boundary conditions, a differential system is written. In particular, the Strong Formulation (SF) of the governing equations is obtained. The differentiability requirement, instead, is reduced through a weighted integral statement if the corresponding Weak Formulation (WF) of the governing equations is developed. Thus, an equivalent integral formulation is derived, starting directly from the previous one. In particular, the formulation in hand is obtained by introducing a Lagrangian approximation of the degrees of freedom of the problem. The need of studying arbitrarily shaped domains or characterized by mechanical and geometrical discontinuities leads to the development of new numerical approaches that divide the structure in finite elements. Then, the strong form or the weak form of the fundamental equations are solved inside each element. The fundamental aspects of this technique, which the author defined respectively Strong Formulation Finite Element Method (SFEM) and Weak Formulation Finite Element Method (WFEM), are presented in the book.

Author: Giorgio Fronza
Publisher:
ISBN:
Category :
Languages : it
Pages : 143

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Author: Francesco Tornabene
Publisher: Società Editrice Esculapio
ISBN: 8835328993
Category : Technology & Engineering
Languages : en
Pages : 1199

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This book aims to present in depth several Higher-order Shear Deformation Theories (HSDTs) by means of a unified approach for the mechanical analysis of doubly-curved shell structures made of anisotropic and composite materials. In particular, the strong and weak formulations of the corresponding governing equations are discussed and illustrated. The approach presented in this volume is completely general and represents a valid tool to investigate the structural behavior of many arbitrarily shaped structures. An isogeometric mapping procedure is also illustrated to this aim. Special attention is given also to advanced and innovative constituents, such as Carbon Nanotubes (CNTs), Variable Angle Tow (VAT) composites and Functionally Graded Materials (FGMs). In addition, several numerical applications are developed to support the theoretical models. Accurate, efficient and reliable numerical techniques able to approximate both derivatives and integrals are presented, which are respectively the Differential Quadrature (DQ) and Integral Quadrature (IQ) methods. Finally, two numerical techniques, named Strong Formulation Finite Element Method (SFEM) and Weak Formulation Finite Element Method (WFEM), are developed to deal with multi-element domains characterized by arbitrary shapes and discontinuities.

Author: Francesco Tornabene
Publisher: Società Editrice Esculapio
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 1073

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This book aims to present in depth several Higher-order Shear Deformation Theories (HSDTs) by means of a unified approach for studying the Hygro-Thermo-Magneto-Electro- Elastic Theory of Anisotropic Doubly-Curved Shells. In particular, a general coupled multifield theory regarding anisotropic shell structures is provided. The three-dimensional multifield problem is reduced in a two-dimensional one following the principles of the Equivalent Single Layer (ESL) approach and the Equivalent Layer-Wise (ELW) approach, setting a proper configuration model. According to the adopted configuration assumptions, several Higher-order Shear Deformation Theories (HSDTs) are obtained. Furthermore, the strong and weak formulations of the corresponding governing equations are discussed and illustrated. The approach presented in this volume is completely general and represents a valid tool to investigate the physical behavior of many arbitrarily shaped structures. An isogeometric mapping procedure is also illustrated to this aim. Special attention is given also to advanced and innovative constituents, such as Carbon Nanotubes (CNTs), Variable Angle Tow (VAT) composites and Functionally Graded Materials (FGMs). In addition, several numerical applications are used to support the theoretical models. Accurate, efficient and reliable numerical techniques able to approximate both derivatives and integrals are considered, which are respectively the Differential Quadrature (DQ) and Integral Quadrature (IQ) methods. The Theory of Composite Thin Shells is derived in a simple and intuitive manner from the theory of thick and moderately thick shells (First-order Shear Deformation Theory or Reissner- Mindlin Theory). In particular, the Kirchhoff-Love Theory and the Membrane Theory for composite shells are shown. Furthermore, the Theory of Composite Arches and Beams is also exposed. In particular, the equations of the Timoshenko Theory and the Euler-Bernoulli Theory are directly deducted from the equations of singly-curved shells of translation and of plates.

Author: Raffaella Carloni
Publisher:
ISBN: 8874882971
Category : Mathematics
Languages : it
Pages : 332

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