Antonio Carcaterra

• PhD
• Professor at Sapienza University of Rome

We consider the time evolution of a one dimensional $n$-gradient continuum. Our aim is to construct and analyze discrete approximations in terms of physically realizable mechanical systems, called microscopic because they are living on a smaller space scale. We validate our construction by proving a convergence theorem of the microscopic system to...

The present paper considers the problem of realizing an effective targeted energy pumping from a linear oscillator to a set of ungrounded linear resonators attached to it. Theoretical as well as numerical results demonstrate the efficacy of using a complex attachment as a passive absorber of broadband energy injected into the primary structure. The...

This paper introduces the temperature concept for Hamiltonian systems to describe the energy flow between two coupled sub-systems. As a result, a general and strict method to approach the energy analysis of linear and nonlinear systems, with potential applications both in theoretical mechanics as well as in engineering Statistical Energy Analysis i...

Hilbert–Huang transform (HHT) is an innovative data-processing technique for analyzing nonstationary and nonlinear signals. A novel HHT-based method for damage detection of bridge structures under a traveling load is proposed. The technique uses a single point measurement and is able to identify the presence and the location of the damage along the...

While pileups involving only two vehicles showcase obvious liability among the drivers, the assessment of liabilities is much more complex in chain collisions. In this work we propose an analytical indicator, named xEES, which easily allows to assess the correct liabilities among drivers. The name is mutated by the concept of energy equivalent spee...

Energy harvesting represents one of the recent challenging subjects related to vibration and control. The scale of energy harvesters and storage can involve a wide power range, and the scale of some milliwatt is the elective field of piezoelectric applications. This paper investigates the power frontiers of the piezoelectric-based harvesters applie...

This paper describes a general physical background that originates integro-differential problems with specific reference to aero-elastic coupling, and offers two techniques of control for this class of problems. The central result of the paper is that integro-differential equations with kernel exponential series admit an optimal solution described,...

This work examines the possibility of developing a class of long-range metamaterials in which the long-range operators are resonator units, like those in the context of locally resonant acoustic metamaterials. Through a simple example, it is demonstrated how a long-range resonator-based metamaterial captures interesting characteristics, stemmed fro...

This paper is concerned with emergence of novel effects in wave propagation in one-dimensional waveguides, when integrated with periodic nonlocalities. The nonlocalities are introduced by a connectivity superimposed to a conventional waveguide and depicted as a graph with trees and leaves, each with its own periodicity. Merging nonlocality and peri...

Long-span suspension bridges are characterized by a high bending-torsional slenderness. Such high compliance together with the high width-to-depth ratio of the typical boxed, sharp-edge, deck cross sections emphasize the dynamic effects of the aerodynamic loads ensuing from wind-structure interaction. Thus, when subject to severe wind excitations,...

A novel indirect variational optimal control theory is proposed for integral-differential equations of motion. This algorithm is applied to an engineering application: the control of a an underawater autonomous vehicle’s 2-Dof lifting surface. The variational approach proposed is an extension of the classical Potryagin optimal control theory which...

We investigate new phenomena in elastic wave propagation in metamaterials characterized by long-range interactions. The kind of waves in this context reveal wave-stopping, negative group velocity, instability, and hypersonic or superluminal effects both for instantaneous and for nonlocal retarded actions. Closed-form results are presented and a uni...

Given the huge rising interest in autonomous drone swarms to be employed in actual marine applications, the present paper explores the possibility to recover a distressed vessel by means of the other agents belonging to the swarm itself. Suitable approaches and control strategies are developed and tested to find the highest performance algorithms....

The analysis of oscillating systems controlled by mechatronic devices, relies classically on differential equations, and the problem is frequently attacked in the frequency domain, for linear systems based on more conventional controls, or in the time space-state formulation to include also nonlinearities. In this paper we are faced with a system t...

This poster is about a novel optimal control indirect algorithm for integro-differential equations. The innovative variational control method is applied to the control of fluctuations of an unmanned vehicle for underwater surveillance military applications. The motion of the vehicle is affected by memory effects due to the fluid-structure interacti...

Nonlocal long-range effects are at the base of new phenomena investigated by the authors. In one dimensional systems, this permits the chance of modifying the phase and group velocity of the waveguide, even producing waves transporting energy backwards. In the two-dimensional case a richer scenario is opened. This paper investigates the chance of t...

A method to design a new type of metamaterial is presented. A two-step strategy to define an optimal long-range force distribution embedded in an elastic support to control wave propagation is considered. The first step uses a linear quadratic regulator (LQR) to produce an optimal set of long-range interactions. In the second step, a least square p...

The use of magnetic dipoles embedding in an elastic support introduces long-range interaction forces. This is a completely new paradigm in structural mechanics, classically based on local short-range particle interaction. The features of long-range forces produce very new mechanical coupling effects. This paper examines the case in which two identi...

In the field of vibrations of complex structures, energy methods like SEA and a series of mid-frequency methods, represent an important resource for computational analysis. All these methods are based in general on a linear formulation of the elastic problem. However, when nonlinearities are present, for example related to clearance or stiffening o...

New suspension systems electronically controlled are presented and mounted on board of a real car. The system consists of variable semi-active magneto-rheological dampers that are controlled through an electronic unit that is designed on the basis of a new optimal theoretical control, named VFC-Variational Feedback Controller. The system has been m...

This paper expands a recent proposal by the authors to rederive the Langevin equation for a test particle in a finite-size thermal bath using a perturbation approach that yields a cascade of Langevin-type equations. Such an approach produces a different viewpoint for the fluctuation-dissipation duality by expressing them on similar scales. General...

The present paper contains the description of a new technology for optical strain measurements in rolling tires. The apparatus is based on the use of Fiber Bragg Gratings sensors and light spectrum analyzer. With the help of a new analytical model, describing the tire strain during its revolution, the experiments permit, for the first time, to prov...

Energy harvesting from environment vibration is an important aspect of many technologies. The scale of energy capturing and storage can involve the power range from mwatt up to Mwatt, depending on the used devices and the considered environments (from ambient acoustic and vibration , to ocean wave motion). In this paper the energy harvesting proble...

The present paper reports on the application of the VFC (Variational Feedback Control) to the mitigation of the vibrational motion of continuous structures. The control method has been very recently proposed in the context of mechanical engineering to obtain suspensions characterized by better comfort performances. In this paper the same methodolog...

This paper considers the damping induced on a single degree-of-freedom system when it is coupled at one end of a waveguide in which waves are radiated producing an energy loss in the oscillator motion that appears as a damping effect. In general, the whole system is described by the equation of the motion of the harmonic oscillator coupled with the...

The theory of vibration of engineering structures belongs to a known chapter of mechanics. Nevertheless, new emerging technologies operating at the smallest scales open a completely new landscape in the field of nanodevices, nanostructured materials as well as biological systems. Nanoscale structures are always involved and characterized by extreme...

The actual capability of monitoring mechanical systems is based on new generation of sensors, modeling and algorithms for the detection of properties, operating conditions and/or failures of the monitored system. The present paper, on the basis of several projects in progress at the University La Sapienza, Rome, illustrates the combination of new s...

In this work we present the results of a field trial with a FBG sensor array system for the real time monitoring of railway traffic and for the structural health monitoring of both the railway track and train wheels. The test campaigns are performed on the on the 2nd line of Milan metropolitan underground, employing more than 50 FBG sensors along 1...

In this paper, we propose the mathematical model of a novel device, the nanomechanical transistor, able to control a current through a small drive voltage. The novelty of the device relies in its mechanical working principle where nanopillars vibrate between electrodes under a self-excitation regime which provides a continuative electric charge tra...

The introduction of vibration-based Nano Electro-Mechanical Transistors (NEMT) opens a new horizon for mechanics in computer science. NEMT working principle is based on an electrical charge shuttle between two electrodes operated by a vibrating conductor body. Advantages of these novel devices would be very low power dissipation, limited influence...

Why it is difficult to solve a vibroacoustic problem; what are the hidden pitfalls that one is called to overcome; are there methods or techniques suggested in other fields of physics that can help to formulate an efficient vibroacoustic prediction model? The authors provide personal answers to these questions and suggest also a classification of t...

Parameters identification of nonstationary systems is a very challenging topic that has only recently received critical attention from the research community. Aim of the paper is the structural health monitoring of bridge-like structures excited by a massive moving load, whose characteristics, such as the mass and speed, are unknown, in the presenc...

This paper presents the theory of a novel mechanism of energy absorption and induced damping in structural systems and its application to aerospace industry. The underlying principles of the physical phenomena have been addressed in several earlier publications, which focused on prototypical systems of absorbers that consist of a set of single-degr...

This paper presents a novel approach to the study of shock in elastic structures. An energy storage property for linear elastic non-dissipative structures is demonstrated, then extrapolated also to damped systems. This property relates locations of energy accumulation along the structure to the form of its stiffness and mass matrices. This result c...

Variational methods give an efficient and elegant way to formulate and solve mathematical problems that are of interest to scientists and engineers. In this book three fundamental aspects of the variational formulation of mechanics will be presented: physical, mathematical and applicative ones. The first aspect concerns the investigation of the na...

In the context of mid- and high-frequency problems in acoustics and vibrations, the modelling of complex systems generates several difficulties, partially related to the large number of degrees of freedom in the discretised model. That makes the problem computationally heavy and very sensitive also to uncertainties in the data. For this reason, in...

. This paper describes a physical and a mathematical model of a new device called nanomechanical transistor able to control a current through a small pilot voltage. The novelty of the device relies in its mechanical working principle where nanopillars vibrate between electrodes providing a mechanical shuttling mechanism for electric charge transpor...

: Hilbert-Huang transform (HHT) is an innovative data-processing technique for analyzing nonstationary and nonlinear signals. A novel HHT-based method for damage detection of bridge structures under a travelling load is proposed. The technique uses a single point measurement and is able to identify the presence and the location of the damage along...

In the context of a new project named SEALAB, aimed at conceiving an innovative high speed marine vehicle, a new system for monitoring the structural response and potential damages in the ship structures is under development. This system permits the real-time self-monitoring of the structure using a new system of sensor based on optical fibers equi...

We investigate the interaction of a particle with a finite-size bath represented by a set of independent linear oscillators with frequencies that fall within a finite bandwidth. We discover that when the oscillators have particular frequency distributions, the finite-size bath behaves much as an infinite-size bath exhibiting dissipation properties...

This paper discusses the question of the energy confinement in mechanical structures in the light of the uncertainties affecting the natural frequencies of the system. More precisely, recent studies have shown that energy can be introduced to a linear system with near irreversibility, or energy within a system can migrate to a subsystem nearly irre...

. The paper presents an overview on the SEALAB project, a technology platform to develop new concepts in design of high-speed marine vehicles. In particular in this paper the aero-hydro-mechanics of the new vessel is discussed, with the aim of developing analytical and numerical models to describe its response and to optimize the navigation perform...

One of the most challenging field in structural dynamics is related to high frequency vibrations. These problems are born in vibration-acoustic analysis, with special interest in automotive or aerospace industry, where the capability of prediction of the noise response of the vehicle and the enhancement of its vibro-acosutic performance has a strat...

In the context of a new project named SEALAB, aimed at conceiving an innovative high speed marine vehicle, a new system for monitoring the structural response and potential damages in the ship structures is under development. This system permits the real-time self-monitoring of the structure using a new system of sensor based on optical fibers equi...

Statistical vibroacoustics, also called statistical energy analysis (SEA) in the field of engineering, is born from the application of statistical physics concepts to the study of random vibration in mechanical and acoustical systems. This article is a discussion on the thermodynamic foundation for that approach with particular emphasis devoted to...

Studies on prototypical systems that consist of a set of complex attachments, coupled to a primary structure characterized by a single degree of freedom system, have shown that vibratory energy can be transported away from the primary through use of complex undamped resonators. Properties and use of these subsystems as by energy absorbers have also...

As reported in several recent publications, an undamped simple oscillator with a complex attachment that consists of a set of undamped parallel resonators can exhibit unusual energy sharing properties. The conservative set of oscillators of the attachment can absorb nearly all the impulsive energy applied to the primary oscillator to which it is co...

The question of energy sharing among complex engineering vibrating systems is still an open problem. On the basis of some recent investigations, this paper is addressed to the prediction of the equilibrium energies of interacting conservative resonators and to a better understanding of the principle of energy equipartition for large undamped system...

Studies on prototypical systems that consist of a set of complex attachments, coupled to a primary structure characterized by a single degree of freedom system, have shown that vibratory energy can be transported away from the primary through use of complex undamped resonators. Properties and use of these subsystems as by energy absorbers have also...

This presentation describes the underlying physics and theory of pseudo damping to reduce vibration of conservative structures. The theoretical approach is based on particular properties of harmonic functions that lead to construction of a complex system that exhibits nearly irreversible energy transfer. This approach also provides the ability to t...

This paper is inspired by some recent studies related to the effect of vibration absorption from a set of resonators when attached to a main structure. In fact, a cluster of phase incoherent resonators can absorb very effectively the energy of a primary vibrating structure to which it is attached, that amounts to an apparent damping effect. In part...

The dynamic response characterization of a complex system comprises of multiple heterogeneous substructures remains one of the most challenging problems in structural dynamics. Inherent uncertainties and the high dimensionality of the problem led to develop approaches imported also from other areas of physics and engineering. In this paper a new ap...

Two statistical techniques are developed to predict the statistical moments of the horizontal motion of a floating moored dock, known as catenary anchor leg mooring (CALM), loaded by hydrodynamic random forces. The dock is represented by a lumped mass, the mooring cables by equivalent nonlinear springs and the hydrodynamic forces are modelled by a...

Pseudo-damping is a counter-intuitive phenomenon observed in a special class of linear structures that exhibit an impulse response characterized by a decaying amplitude, even in the absence of any dissipation mechanism. The conserved energy remains within but designated parts of the system. Pseudo-damping develops when the natural frequency distrib...

The complex envelope displacement analysis (CEDA) is a procedure to solve high frequency vibration and vibro-acoustic problems, providing the envelope of the physical solution. CEDA is based on a variable transformation mapping the high frequency oscillations into signals of low frequency content and has been successfully applied to one-dimensional...

This study extends the previous applications of linear energy sinks to steady‐state vibration absorption. First developed for the absorption of transient vibrations, linear energy sinks also act as effective vibration absorbers under steady‐state excitation. However, their effectiveness depends on the value of excitation frequency with respect to t...

This paper discusses a class of unexpected irreversible phenomena that can develop in linear conservative systems and provides a theoretical foundation that explains the underlying principles. Recent studies have shown that energy can be introduced to a linear system with near irreversibility, or energy within a system can migrate to a subsystem ne...

Pseudo‐damping is a counter‐intuitive phenomenon observed in a special class of linear structures that exhibit an impulse response characterized by a decaying amplitude, even in the absence of any dissipation mechanism. The conserved energy remains within but designated parts of the system. Pseudo‐damping develops when the natural frequency distrib...

This presentation addresses a class of irreversible phenomena that can develop in linear conservative systems and provides a theoretical foundation to explain the underlying principles. Recent studies have shown that energy can be introduced to a linear system with near irreversibility, or energy within a system can migrate to a subsystem nearly ir...

Through two complementary approaches, using modal response and wave propagation, this presentation will show the conditions under which a decaying impulse response, or a nearly irreversible energy trapping, takes place in a linear conservative continuous system. The results show that the basic foundation of near‐irreversibility or pseudo‐damping re...

Through two complementary approaches, using modal response and wave propagation, the analyses presented here show the conditions under which a decaying impulse response, or a nearly irreversible energy trapping, takes place in a linear conservative continuous system. The results show that the basic foundation of near-irreversibility or apparent dam...

This paper illustrates a class of mechanical systems exhibiting a damping mechanism based on fractional derivatives. In particular it is shown how a set of small oscillators of appropriate characteristics attached to an oscillator of larger mass produces an effect that globally can amount to a fractional derivative dissipation mechanism. More preci...

The complex envelope vectorization (CEV) is an alternative technique to SEA and other recent energy methods developed to study high frequency problems. Notwithstanding the large efforts devoted to this topic for many years, there is not yet an appropriate technique to tackle it efficiently. In the framework of an Italian research project "Novel met...

This paper attempts to introduce a new point of view on energy analysis in structural dynamics with particular emphasis to its link with uncertainty and complexity. A linear, elastic system undergoing free vibrations, is considered. The system is subdivided into two subsystems and their respective energies together with the shared energy flow are a...

This paper presents experiments that demonstrate the concept of energy sinks, which when attached to a vibrating structure can absorb most of its energy. Energy sinks consist of a set of undamped linear oscillators and, in principle, do not require presence of damping in the classical sense. The set of undamped oscillators that make up an energy si...

This paper describes a new concept referred to here as ``energy sinks'' as an alternative to conventional methods of vibration absorption and damping. A prototypical energy sink envisioned here consists of a set of oscillators attached to, or an integral part of, a vibrating structure. The oscillators that make up an energy sink absorb vibratory en...

The problem of an elastic lifting hydrofoil in a randomly perturbed flow is considered. It appears that in these conditions the phenomenon of hydroelastic-induced vibrations is controlled by a stochastic differential operator. By using the theory of stochastic perturbation, a technique of solution for this class of problems is proposed, leading to...

This presentation describes experiments that demonstrate the concept of energy sinks where a set of multiple undamped linear oscillators attached to a vibrating structure can absorb most of its energy. In principle, energy sinks do not require presence of damping in the classical sense. A set of undamped oscillators that make up an energy sink coll...

This presentation offers the concept of energy sinks as an alternative to conventional methods of vibration absorption and damping. A prototypical energy sink envisioned here consists of a set of oscillators attached to, or an integral part of, a vibrating structure. The oscillators that make up an energy sink absorb vibratory energy from a structu...