Skip to main content

2015 | Buch

Advanced Dynamics of Mechanical Systems

insite
SUCHEN

Über dieses Buch

This book introduces a general approach for schematization of mechanical systems with rigid and deformable bodies. It proposes a systems approach to reproduce the interaction of the mechanical system with different force fields such as those due to the action of fluids or contact forces between bodies, i.e., with forces dependent on the system states, introducing the concepts of the stability of motion. In the first part of the text mechanical systems with one or more degrees of freedom with large motion and subsequently perturbed in the neighborhood of the steady state position are analyzed. Both discrete and continuous systems (modal approach, finite elements) are analyzed. The second part is devoted to the study of mechanical systems subject to force fields, the rotor dynamics, techniques of experimental identification of the parameters and random excitations. The book will be especially valuable for students of engineering courses in Mechanical Systems, Aerospace, Automation and Energy but will also be useful for professionals. The book is made accessible to the widest possible audience by numerous, solved examples and diagrams that apply the principles to real engineering applications.

Inhaltsverzeichnis

Frontmatter
Chapter 1. Nonlinear Systems with 1-n Degrees of Freedom
Abstract
This chapter of the book describes the large motion non-linear dynamics of multi-body discrete 1, 2 and “n” degree-of-freedom systems using scalar and matrix methodologies (Lagrange’s equations) to write the related equations of motion. Concepts regarding the degrees of freedom of mechanical systems (associated with constraints and their schematization), physical variables and independent coordinates are introduced. The equations of “motion in large” and their linearization in the neighborhood of the equilibrium position (static or steady state) are introduced and described. For 3D motions, the basic concepts of multi-body methods are shown. Several examples are shown in the text.
Federico Cheli, Giorgio Diana
Chapter 2. The Dynamic Behaviour of Discrete Linear Systems
Abstract
This chapter outlines the dynamic behaviour of discrete systems described by linear or linearized equations of motion. From an engineering point of view, this approach simplifies the modelling of machines and mechanical systems subject to vibrations. One, two up to n-degree-of-freedom (d.o.f.) systems are considered, by writing the related equations of motion both in scalar and matrix form. Solution methods for the resulting equations are described for both free and forced motion. Several numerical examples are shown. At the end of the chapter the modal approach in principal coordinates for discrete n d.o.f. systems is illustrated.
Federico Cheli, Giorgio Diana
Chapter 3. Vibrations in Continuous Systems
Abstract
In this chapter, continuous body models (i.e. systems with infinite degrees of freedom, governed by partial differential equations, functions of both time and space) are introduced. As is known, closed form solutions can only be obtained in some simple applications. For this reason, the study was conducted mainly for educational purposes, in preparation for the discretization methods described in the following chapter. In particular, vibrations in continuous systems, using both the direct (the “propagative” solution) and modal approach in principal coordinates (the “stationary” solution), have been studied. At the end of the chapter, the bending vibrations of cables, beams and “taut beams” are shown as examples.
Federico Cheli, Giorgio Diana
Chapter 4. Introduction to the Finite Element Method
Abstract
This chapter deals with the study of the dynamics of continuous mechanical systems using the approximated finite element discretization approach. The general methodology used to define the matrix equations of motion in the case of vibration problems is described. Cable, beam and “taut beam” finite elements are analysed as examples of application; notions regarding two-dimensional and three-dimensional finite elements are shown. The basics concepts regarding the finite element method approach for nonlinear systems and methods of numerical integration of the nonlinear equations of motion are introduced.
Federico Cheli, Giorgio Diana
Chapter 5. Dynamical Systems Subjected to Force Fields
Abstract
This chapter introduces the mechanical systems subjected to force fields, where the excitation depends on the state of the system. As known, these force fields can change the stability characteristics of the mechanical system. The analyses is conducted by introducing the force field characteristics (positional or velocity dependent forces) obtained by linearizing the equations of motion (for 1, 2 and “n” degree-of-freedom systems) in the neighborhood of the static equilibrium position. Stability is analyzed by applying the eigenvalues-eigenvector approach. Some real applications are presented: aerodynamic forces on airfoils, contact force effects in cutting tools, hydrodynamic lubrication in journal bearings and contact force effects in rail and road vehicles. Some real applications are presented: aerodynamic forces on airfoils, contact force effects in cutting tools, hydrodynamic lubrication in journal bearings and contact force effects in rail and road vehicles.
Federico Cheli, Giorgio Diana
Chapter 6. Rotordynamics
Abstract
This chapter deals specifically with rotor dynamics, introduced as a complete application example of a mechanical system subjected to force fields. The text defines the most common layouts used in these machines and the numerical models adopted to simulate their dynamic behaviour. Vibration and stability problems are analysed, also with reference to critical bending and torsional speeds. Other problems associated with “n-per-rev” vibrations, material hysteresis and gyroscopic effects are also analysed. Some methods used for rotor balancing are described at the end of the chapter.
Federico Cheli, Giorgio Diana
Chapter 7. Random Vibrations
Abstract
This chapter introduces the basic concepts related to random vibrations. After a brief description of the methods that can be used to analyse such processes, three application examples, related to structure response to turbulent wind and to wave motion, are presented. The approach used to evaluate the irregularity of road and rail-track (to simulate the dynamic behavior of vehicles under this type of excitation) is shown at the end of the chapter.
Federico Cheli, Giorgio Diana
Chapter 8. Techniques of Identification
Abstract
The basic concepts related to parameter identification techniques are summarized in this final chapter. These methodologies allow for the identification of some unknown parameters of numerical simulation models of machines and structures, starting from experimental tests on prototypes or real structures. In particular, the text describes modal identification techniques, both in the time and frequency domain. Some examples are given.
Federico Cheli, Giorgio Diana
Metadaten
Titel
Advanced Dynamics of Mechanical Systems
verfasst von
Federico Cheli
Giorgio Diana
Copyright-Jahr
2015
Electronic ISBN
978-3-319-18200-1
Print ISBN
978-3-319-18199-8
DOI
https://doi.org/10.1007/978-3-319-18200-1

    Marktübersichten

    Die im Laufe eines Jahres in der „adhäsion“ veröffentlichten Marktübersichten helfen Anwendern verschiedenster Branchen, sich einen gezielten Überblick über Lieferantenangebote zu verschaffen.