Giuseppe Habib

Giuseppe Habib
Budapest University of Technology and Economics · Department of Applied Mechanics

PhD

About

54
Publications
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691
Citations

Publications

Publications (54)
Article
Full-text available
Parametric excitation in the pitch/roll degrees of freedom (DoFs) can induce dynamic instability in floating cylinder-type structures such as spar buoys, floating offshore wind or wave energy converters. At certain frequency and amplitude ranges of the input waves, parametric coupling between the heave and pitch/roll DoFs results in undesirable lar...
Article
Full-text available
This study pertains to analysing the dynamical behaviour of a floating body undergoing parametric resonances. A simple vertical cylinder, representing a classical spar-buoy, is considered, limiting its motion to heave and pitch degrees of freedom. Its geometry and mass distribution are chosen such that a 2:1 ratio of heave to pitch/roll natural fre...
Article
Full-text available
Stability and bifurcation analysis of a non-rigid robotic arm controlled with a time-delayed acceleration feedback loop is addressed in this work. The study aims at revealing the dynamical mechanisms leading to the appearance of limit cycle oscillations existing in the stable region of the trivial solution of the system, which is related to the com...
Article
Conventional nonlinear energy sinks (NES) are considered to be a more robust alternative to linear vibration absorbers such as the tuned-mass-damper (TMD). While the conventional NES has a larger efficient frequency bandwidth than the TMD, it is only really efficient for a small energy range. This implies a deterioration of the NES's mitigation pro...
Conference Paper
Full-text available
A new algorithm for estimating the robustness of a dynamical system's equilibrium is presented. Unlike standard approaches, the algorithm does not aim to identify the entire basin of attraction of the solution. Instead, it iteratively estimates the so-called local integrity measure, i.e., the radius of the largest hypersphere entirely included in t...
Conference Paper
Full-text available
Various active and passive methods for vibration mitigation exist, each presenting its own advantages and drawbacks. The objective of this study is to compare the performance of a hybrid active-passive dynamic vibration absorber and of a purely passive one, with respect to their ability in suppressing self-excited oscillations. The host system cons...
Article
Full-text available
A new algorithm for the estimation of the robustness of a dynamical system’s equilibrium is presented. Unlike standard approaches, the algorithm does not aim to identify the entire basin of attraction of the solution. Instead, it iteratively estimates the so-called local integrity measure, that is, the radius of the largest hypersphere entirely inc...
Article
Full-text available
A nonlinear energy sink (NES), conceived to mitigate the vibrations of a multi-degree-of-freedom host mechanical system, is considered. The high-dimensional slow invariant manifold (SIM) describing the high-amplitude slow dynamics of the system is derived and exploited to interpret its transient regimes caused by impulsive excitation. It is shown t...
Article
Full-text available
Friction-induced vibrations are a significant problem in various engineering applications, while dynamic vibration absorbers are an economical and effective tool for suppressing various kinds of vibrations. In this study, the archetypal mass-on-moving-belt model with an attached dynamic vibration absorber was considered. By adopting an analytical p...
Article
Full-text available
Mathematical models are essential for the design and control of offshore systems, to simulate the fluid-structure interactions and predict the motions and the structural loads. In the development and derivation of the models, simplifying assumptions are normally required, usually implying linear kinematics and hydrodynamics. However, while the assu...
Conference Paper
Full-text available
The implementation of the tuned mass damper (TMD) for the suppression of shimmy vibration in towed wheels is addressed in this study. We adopt a modified straight tangent tyre model of a single degree-of-freedom towed wheel system, with an attached TMD. Stability analysis illustrated that the TMD can significantly improve the stability of the equil...
Chapter
A comparative study between a tuned mass damper (TMD) and a nonlinear energy sink (NES), attached to a linear two-degree-of-freedom (DoF) mechanical system under impulsive excitation, is performed. The analysis involves different scenarios; namely, we consider the cases in which only one or both modes of the primary system are initially excited. Fi...
Article
Full-text available
The dynamics of a nonlinear passive vibration absorber conceived to mitigate vibrations of a nonlinear host structure is considered in this paper. The system under study is composed of a primary system, consisting of an undamped nonlinear oscillator of Duffing type, and a nonlinear dynamic vibration absorber, denominated nonlinear tuned vibration a...
Preprint
Full-text available
The dynamics of a nonlinear passive vibration absorber conceived to mitigate vibrations of a nonlinear host structure is considered in this paper. The system under study is composed of a primary system, consisting of an undamped nonlinear oscillator of Duffing type, and a nonlinear dynamic vibration absorber, denominated nonlinear tuned vibration a...
Article
The unsafe zone in machining is a region of the parameter space where steady-state cutting operations may switch to regenerative chatter for certain perturbations, and vice versa. In the case of milling processes, this phenomenon is related to the existence of an unstable quasi-periodic oscillation, the in-sets of which limit the basin of attractio...
Article
Two important properties of linear systems, namely force-displacement proportionality and resonance frequency invariance, are generally not satisfied by nonlinear systems. With the objective to enlarge the range over which a nonlinear system behaves linearly, this paper attempts to enforce those properties through the addition of properly-tuned non...
Chapter
Full-text available
A tuned mass damper (TMD) is implemented for the suppression of delay-induced vibrations. An inverted pendulum subject to proportional-derivative feedback control is considered as primary system. A TMD is then attached to it, in order to enlarge the stable region in the space of the control gains and mitigate vibrations induced by time delay in the...
Article
Full-text available
We analyze isolated resonance curves (IRCs) in single-degree-of-freedom systems possessing nonlinear damping. Through the combination of singularity theory and the averaging method, the onset and merging of IRCs, which coincide to isola and simple bifurcation singularities, respectively, can be analytically predicted. Numerical simulations confirm...
Chapter
Important properties of linear systems, such as force-displacement proportionality and invariance of the resonant frequency, are not satisfied by nonlinear systems. The objective of this paper is to demonstrate that the intentional addition of properly tuned nonlinearities to a nonlinear system allows to retrieve those linear properties, enlarging...
Article
In the last decade, the problem of detached resonant curves (DRCs) has received a growing attention. However, most of recent research works seem to ignore papers from the sixties and the seventies, which already investigated the subject. With the aim of recovering this “forgotten” literature, we briefly review the majority of the studies on the top...
Article
Full-text available
Digitization and time delay are known to modify the stability properties of feedback controlled systems. Although their effects have been widely investigated and they occur in most of the systems equipped with digital processors, they are usually neglected in industrial approaches, by virtue of the high sampling frequencies of modern processors. Ho...
Article
Full-text available
A bistable nonlinear energy sink conceived to mitigate the vibrations of host structural systems is considered in this paper. The hosting structure consists of two coupled symmetric linear oscillators (LOs), and the nonlinear energy sink (NES) is connected to one of them. The peculiar nonlinear dynamics of the resulting three-degree-of-freedom syst...
Article
Full-text available
The influence of a nonlinear tuned vibration absorber (NLTVA) on the airfoil flutter is investigated. In particular, its effect on the instability threshold and the potential subcriticality of the bifurcation is analyzed. For that purpose, the airfoil is modeled using the classical pitch and plunge aeroelastic model together with a linear approach...
Article
Full-text available
A passive vibration absorber, termed the nonlinear tuned vibration absorber (NLTVA), is designed for the suppression of chatter vibrations. Unlike most passive vibration absorbers proposed in the literature for suppressing machine tool vibrations, the NLTVA comprises both a linear and a nonlinear restoring force. Its linear characteristics are tune...
Conference Paper
Full-text available
A passive vibration absorber, termed the nonlinear tuned vibration absorber (NLTVA), is designed for the suppression of chatter vibrations. Unlike most passive vibration absorbers proposed in the literature, the NLTVA comprises both a linear and a nonlinear restoring force. Its linear characteristics are tuned in order to optimize the stability pro...
Article
The current drive for increased efficiency in aeronautic structures such as aircraft, wind-turbine blades, and helicopter blades often leads to weight reduction. A consequence of this tendency can be increased flexibility, which in turn can lead to unfavorable aeroelastic phenomena involving large-amplitude oscillations and nonlinear effects such a...
Conference Paper
Full-text available
A passive vibration absorber, termed the nonlinear tuned vibration absorber (NLTVA), is designed for the suppression of chatter vibrations. Differently from most passive vibration absorbers proposed in the literature , the NLTVA comprises both a linear and a nonlinear restoring force. Its linear characteristics are tuned in order to optimize the st...
Article
The objective of this paper is to demonstrate that the addition of properly-tuned nonlinearities to a nonlinear system can increase the range over which a specific resonance responds linearly. Specifically, we seek to enforce two important properties of linear systems, namely the force-displacement proportionality and the invariance of resonance fr...
Article
Bifurcation theory and continuation methods are well-established tools for the analysis of nonlinear mechanical systems subject to periodic forcing. We illustrate the added value and the complementary information provided by singularity theory with one distinguished parameter. While tracking bifurcations reveals the qualitative changes in the behav...
Article
This paper develops a principle of similarity for the design of a nonlinear absorber, the nonlinear tuned vibration absorber (NLTVA), attached to a nonlinear primary system. Specifically, for effective vibration mitigation, we show that the NLTVA should feature a nonlinearity possessing the same mathematical form as that of the primary system. A co...
Conference Paper
Full-text available
Important properties of linear systems, such as force-displacement pro-portionality and invariance of the resonant frequency, are not satisfied by nonlinear systems. The objective of this paper is to demonstrate that the intentional addition of properly tuned nonlinearities to a nonlinear system allows to retrieve those linear properties, enlarging...
Chapter
Engineering structures are designed to be lighter and more flexible, hence reducing the extent of application of linear dynamic models. Concurrently, vibration mitigation is required for enhancing the performance, comfort or safety in real-life applications. Passive linear vibration absorbers are purpose-built, often designed using Den Hartog’s equ...
Chapter
Full-text available
The current trend of developing more slender structures is increasing the importance of nonlinearities in engineering design, which, in turn, gives rise to complicated dynamical phenomena. In this study, we evidence the somewhat paradoxical result that adding purposefully nonlinearity to an already nonlinear structure renders the behavior more line...
Chapter
The current drive for increased efficiency in aeronautic structures such as aircraft, wind turbine blades and helicopter blades often leads to weight reduction. A consequence of this tendency can be increased flexibility, which in turn can lead to unfavourable aeroelastic phenomena involving large amplitude oscillations and nonlinear effects such a...
Conference Paper
With continual interest in expanding the performance envelope of engineering systems, nonlinear components are increasingly utilized in real-world applications. This causes the failure of well-established techniques to mitigate resonant vibrations. In particular, this holds for the linear tuned vibration absorber (LTVA), which requires an accurate...
Article
The objective of this study is to mitigate, or even completely eliminate, the limit cycle oscillations in mechanical systems using a passive nonlinear absorber, termed the nonlinear tuned vibration absorber (NLTVA). An unconventional aspect of the NLTVA is that the mathematical form of its restoring force is not imposed a priori, as it is the case...
Article
The nonlinear tuned vibration absorber (NLTVA) is a recently developed nonlinear absorber which generalizes Den Hartog׳s equal peak method to nonlinear systems. If the purposeful introduction of nonlinearity can enhance system performance, it can also give rise to adverse dynamical phenomena, including detached resonance curves and quasiperiodic re...
Conference Paper
Full-text available
Limit cycle oscillations (LCOs) occur in many mechanical systems and they are often a source of danger. The addition of a relatively small mass to the host system, attached through a linear spring and a damper (linear tuned vibration absorber, LTVA), significantly improves its stability. The use of a purely nonlinear spring in the absorber (nonline...
Conference Paper
Full-text available
The aim of the paper is to develop a new nonlinear tuned vibration absorber (NLTVA) capable of mitigating the vibrations of nonlinear systems which are known to exhibit frequency-energy-dependent oscillations. A nonlinear generalization of Den Hartog's equal-peak method is proposed to ensure equal peaks in the nonlinear frequency response for a lar...
Article
This study addresses the mitigation of one problem nonlinear resonance of a mechanical system. In view of the narrow bandwidth of the classical linear tuned vibration absorber, a new nonlinear absorber, termed the nonlinear tuned vibration absorber (NLTVA), is introduced in this paper. One unconventional aspect of the NLTVA is that the mathematical...
Article
Full-text available
The act-and-wait concept is a recently developed type of controller, which is receiving growing interest because of its promising features with respect to the control of systems with feedback delay. Although most of its advantages have been widely discussed and verified experimentally, a detailed analysis of the nonlinear behavior of this type of c...
Article
Full-text available
This paper analyzes the double Neimark–Sacker bifurcation occurring in a two-DoF system, subject to PD digital position control. In the model the control force is considered piecewise constant. Introducing a nonlinearity related to the saturation of the control force, the bifurcations occurring in the system are analyzed. The system is generally lo...
Article
Full-text available
Considering a two DoF system subject to digital position control, of interest for robotic application, we analyze the dynamics of the system at the intersection of two loci of Neimark–Sacker bifurcations, where a double Neimark–Sacker bifurcation is taking place. In the system, the saturation of the control force is the only nonlinear term consider...
Article
Full-text available
This paper presents an analysis of the stability of a two DoF system, modeling a robotic arm connected to the actuator through an elastic joint and subject to digital position control. The system consists of two lumped masses connected to each other through a spring and a damper. In the model there is only one actuator, so the system is underactuat...
Article
Full-text available
Precision and stability in position control of robots are critical parameters in many industrial applications where high accuracy is needed. It is well known that digital effect is destabilizing and can cause instabilities. In this paper, we analyze a single DoF model of a robotic arm and we present the stability limits in the parameter space of th...
Conference Paper
Full-text available
In this paper we apply the so called act-and-wait control concept, a specific periodic controller, to the digital position control of a single DoF system. We compare the different behavior of the system with and without the periodic controller, with respect to the stability and the bifurcation behavior of the system. The results will show how the p...
Conference Paper
Full-text available
This paper analyzes the stability of a two-DoF system, subject to PD digital position control. In the model the control force is considered piecewise constant. Introducing the nonlinearity related to the saturation of the control force, the bifurcations occurring in the system are analyzed. The system is generally losing stability through Neimark-S...
Article
Full-text available
The analytical investigation of bifurcations is a very challenging task for many applied scientists and engineers. Often, numerical simulations cannot clarify the complicated dynamics of mechanical systems, in this cases, preprogrammed softwares can be of valid help during the investigation. Also, in the literature, methodology to study bifurcation...
Conference Paper
Full-text available
This paper presents an analysis of the stability of a two DoF mechanical model of an elastic robotic arm, subjected to digital position control. The elastic robotic arm is modeled with two lumped masses connected to each other through a spring and a damper. In the model there is only one actuator to control the single elastic arm, so the system is...
Conference Paper
Full-text available
Time delay and digitalization are known to have a destabilizing effect on control systems. Most of the existing literature regarding control systems, uses continuous-time models, because of the high sampling frequency of modern processors. Recent studies show that the digitalization can influence the stability, in spite of high values of the sampli...
Conference Paper
Full-text available
Precision and stability in position control of robots are critical parameters in many industrial applications where high accuracy is needed. It is well known that digital effect is destabilizing and can cause instabilities. In this paper, the stability limits are presented in the parameter space of the control gains, furthermore the bifurcations oc...
Article
Full-text available
We investigate the non-linear damping mechanisms that govern the dynamics of a chaotic spherical pendulum. We reproduce the conditions of the celebrated chaotic experiment of Tritton (1986), and identify the bifurcation regions that correspond to periodic, quasi-periodic and chaotic-like response. Construction of the pendulum frequency and damping...

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Projects

Projects (3)
Project
Dear Colleagues, In the last twenty years, tribology and nonlinear dynamics have included several major contributions related to key topics such as rough contact, friction, damping mechanisms, and dynamical behavior of nonlinear systems, which are paving the way for future engineering challenges. The two fields are largely intertwined as, among the others, contact nonlinearities are almost omnipresent in any technical application ranging from the development of NEMS/MEMS to bioengineering, automotive, civil/mechanical industry, and aerospace. The common thread in both fields is the study of interfaces, particularly of the dissipative phenomena that take place at the interface, providing the source of damping that is exploited to reduce the vibration amplitude of mechanical systems, improving their service life. Despite the great achievements obtained, we are still far from being able to predict the dynamical behaviour of mechanical systems involving contact interfaces. Contamination of knowledge between tribology and nonlinear dynamics is of outmost importance today to develop strategies to respond promptly to future challenges. The current Special Issue aims at bringing together, in the same Issue, contributions from world-leading scientists working in the fields of tribology and nonlinear dynamics, with the goal being to favor “contamination” of knowledge from the two fields to deepen our understanding of engineering regarding interfacial dissipation and dynamical system responses. Contributions are welcome from all scientists working in tribology, dynamics, and related areas. Dr. Antonio Papangelo Guest Editor
Archived project
The main idea of the PIEZOMACH project is to develop a fully passive nonlinear device for suppressing chatter vibrations in machine tools. These vibrations represent a major concern in industry, as they result, for instance, in waves on the machined surface. This project goes beyond the challenge of dealing with the nonlinear nature of chatter vibrations, to developing a device that can unlock the huge potential of nonlinearity to improve dynamic performance. More specifically, the linear characteristic of the absorber will be optimized to maximize its stability properties, while its nonlinear characteristic will be designed in order to avoid dangerous bistable behaviors and guarantee robustness. This technique, successfully implemented for the suppression of aeroelastic instabilities, will be adapted to machine tool vibrations, first analytically and then experimentally, paving the way to the industrial exploitation of the obtained results. The vibration absorber will be practically realized utilizing an RLC resonant circuit coupled to the mechanical structure through a piezoelectric patch.
Archived project
The objective of the ERC - NOVIB project is to control nonlinear instabilities, which include nonlinear resonances, aeroelastic flutter, and machining chatter, through the development of the nonlinear tuned vibration absorber (NLTVA), a new, rigorous nonlinear counterpart of the linear tuned vibration absorber. The innovative idea of the NLTVA is to tailor the mathematical form of the nonlinearity according to the nonlinear phenomena that are at the source of the instability.