36 pubblicazioni classificate nel seguente modo:

Imperfection-induced internal resonance in nanotube resonators
JOURNAL OF SOUND AND VIBRATION
Autore/i: Belardinelli, P; Lenci, S; Alijani, F
Classificazione: 1 Contributo su Rivista
Abstract: Through molecular dynamics simulations, we demonstrate the possibility of internal resonances in single-walled carbon nanotubes. The resonant condition is engineered with a lack of symmetry in the boundary condition and activated by increasing the energy exchange with a coupled thermal bath. The critical temperature threshold for initiating modal interaction is found to be chirality-dependent. By applying the proper orthogonal decomposition algorithm to molecular dynamics time responses, we show how the thermal fluctuations influence the vibrational behaviour of the nanotube leading to both flexural–flexural and flexural–longitudinal resonances. Understanding the interaction between nanotube resonators and the thermal bath is crucial for designing and optimizing their performance for various nanoscale sensing, actuation, and signal processing applications.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/325838

Piecewise integrable neural network: An interpretable chaos identification framework
CHAOS
Autore/i: Novelli, N.; Belardinelli, P.; Lenci, S.
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/311975

Non-Smooth Dynamics of Tapping Mode Atomic Force Microscopy
JOURNAL OF COMPUTATIONAL AND NONLINEAR DYNAMICS
Autore/i: Belardinelli, P; Chandrashekar, A; Alijani, F; Lenci, S
Classificazione: 1 Contributo su Rivista
Abstract: This study examines the nonlinear dynamics in tapping-mode atomic force microscopy (AFM) with tip-surface interactions that include van der Waals and Derjaguin-Muller-Toporov contact forces. We investigate the periodic solutions of the hybrid system by performing numerical pseudo-arclength continuation. Through the use of bifurcation locus maps in the set of parameters of the discontinuous model, the overall dynamical response scenario is assessed. We demonstrate the influence of various dissipation mechanisms that are related with the AFM touching or lacking contact with the sample. Local and global analyses are used to investigate the stability of the stable solution in the repulsive regime. The impacting nonsmooth dynamics framed within a higher-mode Galerkin discretization is able to capture windows of irregular and complex motion.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/320233

Boosting the Model Discovery of Hybrid Dynamical Systems in an Informed Sparse Regression Approach
JOURNAL OF COMPUTATIONAL AND NONLINEAR DYNAMICS
Autore/i: Novelli, Nico; Lenci, Stefano; Belardinelli, Pierpaolo
Classificazione: 1 Contributo su Rivista
Abstract: We present an efficient data-driven sparse identification of dynamical systems. The work aims at reconstructing the different sets of governing equations and identifying discontinuity surfaces in hybrid systems when the number of discontinuities is known a priori. In a two-stage approach, we first locate the switches between separate vector fields. Then, the dynamics among the manifolds are regressed, in this case by making use of the existing algorithm of Brunton et al. (2016, "Discovering Governing Equations From Data by Sparse Identification of Nonlinear Dynamical Systems," Proc. Natl. Acad. Sci., 113(15), pp. 3932-3937). The reconstruction of the discontinuity surfaces comes as the outcome of a statistical analysis implemented via symbolic regression with small clusters (microclusters) and a rigid library of models. These allow to classify all the feasible discontinuities that are clustered and to reduce them into the actual discontinuity surfaces. The performances of the sparse regression hybrid model discovery are tested on two numerical examples, namely, a canonical spring-mass hopper and a free/impact electromagnetic energy harvester (FIEH), engineering archetypes characterized by the presence of a single and double discontinuity, respectively. Results show that a supervised approach, i.e., where the number of discontinuities is pre-assigned, is computationally efficient and it determines accurately both discontinuities and set of governing equations. A large improvement in the time of computation is found with the maximum achievable reliability. Informed regression-based identification offers the prospect to outperform existing data-driven identification approaches for hybrid systems at the expense of instructing the algorithm for expected discontinuities.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/311547

Machine learning to probe modal interaction in dynamic atomic force microscopy
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
Autore/i: Belardinelli, P.; Chandrashekar, A.; Wiebe, R.; Alijani, F.; Lenci, S.
Classificazione: 1 Contributo su Rivista
Abstract: Modal interactions are pervasive effects that commonly emerge in nanomechanical systems. The coupling of vibrating modes can be leveraged in many ways, including to enhance sensing or to disclose complex phenomenologies. In this work we show how machine learning and data-driven approaches could be used to capture intermodal coupling. We employ a quasi-recurrent neural network (QRNN) for identifying mode coupling and verify its applicability on experimental data obtained from tapping mode atomic force microscopy (AFM). Hidden units of the QRNN are monitored to trace fingerprints of modes activation and to quantify their contributions over the global distortion of orbits in the phase space. To demonstrate the broad applicability of the method, the trained model is re-applied over different experiments and on diverse materials. Over a range of tip-sample configurations, dynamic AFM possesses features general enough to be seized by the QRNN and it is not required an ad-hoc re-training for the identification of interacting modes. Our study opens up a route for utilizing established machine learning techniques for rapid recognition of nonlinear complex effect such as internal resonances in nanotechnology. The QRNN analysis is meant to assist AFM sensing operations when exploiting modal interaction to enhance the signal-to-noise ratio of higher harmonics and provide high resolution compositional contrast in multi-frequency AFM applications.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/305780

Quantifying nanoscale forces using machine learning in dynamic atomic force microscopy
NANOSCALE ADVANCES
Autore/i: Chandrashekar, Abhilash; Belardinelli, Pierpaolo; Bessa, Miguel A; Staufer, Urs; Alijani, Farbod
Classificazione: 1 Contributo su Rivista
Abstract: Dynamic atomic force microscopy (AFM) is a key platform that enables topological and nanomechanical characterization of novel materials. This is achieved by linking the nanoscale forces that exist between the AFM tip and the sample to specific mathematical functions through modeling. However, the main challenge in dynamic AFM is to quantify these nanoscale forces without the use of complex models that are routinely used to explain the physics of tip-sample interaction. Here, we make use of machine learning and data science to characterize tip-sample forces purely from experimental data with sub-microsecond resolution. Our machine learning approach is first trained on standard AFM models and then showcased experimentally on a polymer blend of polystyrene (PS) and low density polyethylene (LDPE) sample. Using this algorithm we probe the complex physics of tip-sample contact in polymers, estimate elasticity, and provide insight into energy dissipation during contact. Our study opens a new route in dynamic AFM characterization where machine learning can be combined with experimental methodologies to probe transient processes involved in phase transformation as well as complex chemical and biological phenomena in real-time.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/307121

Sensitivity of viscoelastic characterization in multi-harmonic atomic force microscopy
SOFT MATTER
Autore/i: Chandrashekar, Abhilash; Givois, Arthur; Belardinelli, Pierpaolo; Penning, Casper L.; Aragon, Alejandro M.; Staufer, Urs; Alijani, Farbod
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/307982

Boosting the Model Discovery of Hybrid Dynamical Systems in an Informed Sparse Regression Approach
Volume 9: 17th International Conference on Multibody Systems, Nonlinear Dynamics, and Control (MSNDC)
Autore/i: Novelli, Nico; Lenci, Stefano; Belardinelli, Pierpaolo
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/299086

Mode Coupling in Dynamic Atomic Force Microscopy
PHYSICAL REVIEW APPLIED
Autore/i: Chandrashekar, A.; Belardinelli, P.; Lenci, S.; Staufer, U.; Alijani, F.
Classificazione: 1 Contributo su Rivista
Abstract: Increasing the signal-to-noise ratio in dynamic atomic force microscopy plays a key role in nanomechanical mapping of materials with atomic resolution. In this work, we develop an experimental procedure for increasing the sensitivity of higher harmonics of an atomic-force-microscope cantilever without modifying the cantilever geometry but instead by utilizing dynamical mode coupling between its flexural modes of vibration. We perform experiments on different cantilevers and samples and observe that via nonlinear resonance frequency tuning we can obtain a frequency range where strong modal interactions lead to 7-fold and 16-fold increases in the sensitivity of the 6th and 17th harmonics while reducing sample indentation. We derive a numerical model that captures the observed physics and confirms that nonlinear mode coupling is the reason for the increase of the amplitude of higher harmonics during tip-sample interactions.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/288570

Interrelation of Elasticity and Thermal Bath in Nanotube Cantilevers
PHYSICAL REVIEW LETTERS
Autore/i: Tepsic, S.; Gruber, G.; Møller, C. B.; Magén, C.; Belardinelli, P.; Hernández, E. R.; Alijani, F; Verlot, P; Bachtold, A
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/297041

Second flexural and torsional modes of vibration in suspended microfluidic resonator for liquid density measurements
JOURNAL OF MICROMECHANICS AND MICROENGINEERING
Autore/i: Belardinelli, Pierpaolo; D Souza, Savio N F; Verlinden, Eleonoor; Wei, Jia; Staufer, Urs; Alijani, Farbod; K Ghatkesar, Murali
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/299083

Robustness of attractors in tapping mode atomic force microscopy
NONLINEAR DYNAMICS
Autore/i: Chandrashekar, A.; Belardinelli, P.; Staufer, U.; Alijani, F.
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/267956

Global dynamics and integrity of a micro-plate pressure sensor
COMMUNICATIONS IN NONLINEAR SCIENCE & NUMERICAL SIMULATION
Autore/i: Belardinelli, P.; Sajadi, B.; Lenci, S.; Alijani, F.
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/262764

Inkjet-Printed High-Q Nanocrystalline Diamond Resonators
SMALL
Autore/i: Sartori, A. F.; Belardinelli, P.; Dolleman, R. J.; Steeneken, P. G.; Ghatkesar, M. K.; Buijnsters, J. G.
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/267943

High-Frequency Stochastic Switching of Graphene Resonators Near Room Temperature
NANO LETTERS
Autore/i: Dolleman, Robin J.; Belardinelli, Pierpaolo; Houri, Samer; van der Zant, Herre S. J.; Alijani, Farbod; Steeneken, Peter G.
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/267130

Nonlinear dynamic identification of graphene's elastic modulus via reduced order modeling of atomistic simulations
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
Autore/i: Sajadi, B.; Wahls, S.; Hemert, S. V.; Belardinelli, P.; Steeneken, P. G.; Alijani, F.
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/267953

Revealing compactness of basins of attraction of multi-DoF dynamical systems
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
Autore/i: Brzeski, P.; Belardinelli, P.; Lenci, S.; Perlikowski, P.
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/259290

Modal analysis for density and anisotropic elasticity identification of adsorbates on microcantilevers
APPLIED PHYSICS LETTERS
Autore/i: Belardinelli, P.; Hauzer, L. M. F. R.; Siskins, M.; Ghatkesar, M. K.; Alijani, F.
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/267944

Size- and temperature-dependent bending rigidity of graphene using modal analysis
CARBON
Autore/i: Sajadi, B.; van Hemert, S.; Arash, B.; Belardinelli, P.; Steeneken, P. G.; Alijani, F.
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/267945

Stochastic Switching and Reduction of Integrity in Atomic Force Microscopy
ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference
Autore/i: Belardinelli, Pierpaolo; Lenci, Stefano; Alijani, Farbod
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269428

Seamless variation of isometric and anisometric dynamical integrity measures in basins's erosion
COMMUNICATIONS IN NONLINEAR SCIENCE & NUMERICAL SIMULATION
Autore/i: Belardinelli, P.; Lenci, S.; Rega, G.
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/254150

Improving the Global Analysis of Mechanical Systems via Parallel Computation of Basins of Attraction
Procedia IUTAM
Autore/i: Belardinelli, Pierpaolo; Lenci, Stefano
Editore: Elsevier B.V.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/254141

Linear and non-linear vibrations of fluid-filled hollow microcantilevers interacting with small particles
INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS
Autore/i: Belardinelli, P.; Ghatkesar, M. K.; Staufer, U.; Alijani, F.
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/267949

Nonlinear dynamics for estimating the tip radius in atomic force microscopy
APPLIED PHYSICS LETTERS
Autore/i: Rull Trinidad, E.; Gribnau, T. W.; Belardinelli, P.; Staufer, U.; Alijani, F.
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/267950

A first parallel programming approach in basins of attraction computation
INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS
Autore/i: Belardinelli, Pierpaolo; Lenci, Stefano
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/236476

An efficient parallel implementation of cell mapping methods for MDOF systems
NONLINEAR DYNAMICS
Autore/i: Belardinelli, Pierpaolo; Lenci, Stefano
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/246677

Advances in modeling and nonlinear dynamics of microbeam-based structures
Autore/i: Belardinelli, Pierpaolo
Editore: Università Politecnica delle Marche
Classificazione: 8 Tesi di dottorato
Abstract: Negli ultimi anni l'interesse generale nei dispositivi micro-elettro-meccanici e nano-elettro-meccanici (MEMS e NEMS) è aumentato esponenzialmente, soprattutto grazie all'ampia gamma di applicazioni in molteplici ambiti oltre quello ingegneristico. Lo studio di questi dispositivi e' principalmente guidato da i) l'esigenza pratica di supportatare la fabbricazione dei dispositivi e lo sviluppo evolutivo degli stessi con una modellazione affidabile, ii) l'interesse di scienziati e ricercatori nelle problematiche teorico-matematiche associate a dispositivi di micro e nano-scala. Si e' cosi' aperta una nuova finestra di studio su questioni fondamentali della meccanica ed in particolare nella statica e nella dinamica non lineare. Questa tesi vuole introdurre una modellazione innovativa per quanto riguarda la descrizione del comportamento statico e dinamico di microtravi per dispositivi risonanti. Dopo aver risposto al requisito fondamentale di attendibilita' della modellazione proposta, ulteriore attenzione e' posta alla facilita' di implementazione e non ultimo all'efficienza computazionale. L'approccio proposto in questo lavoro si basa su un modello elastico non classico (strain-gradient elasticity theory) e tiene conto dell'effetto di stretching nonlineare della trave deformata, nonche' di un carico assiale applicato. Un'attuazione elettrica include aspetti di multifisica nel modello ed introduce un'ulteriore fonte di nonlinearita' nelle equazioni: accurate correzioni tengono conto degli effetti di bordo derivanti dal campo elettrico. Dal momento che il comportamento meccanico è strettamente correlato ai fenomeni dissipativi, per comprendere appieno l'effetto dell'accoppiamento termoelastico, la descrizione e' arricchita con le espressioni descrittive dei fenomeni termici, ottenendo cosi' un sistema accoppiato di equazioni differenziali alle derivate parziali. Il modello unificato proposto e' capace di descrivere il comportamento termo-elastico sia attraverso una formulazione classica che con due distinte teorie generalizzate. Le equazioni sono manipolate mediante un metodo di approssimazione spettrale e successive simulazioni numeriche. Diverse analisi vengono effettuate per valutare l'influenza della modellazione non classica nella risposta della trave.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/242968

Vibration frequency analysis of an electrically-actuated microbeam resonator accounting for thermoelastic coupling effects
INTERNATIONAL JOURNAL OF DYNAMICS AND CONTROL
Autore/i: Belardinelli, Pierpaolo; Lenci, Stefano; Demeio, Lucio
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/228375

HPC Methods for Domains of Attraction Computation
ASME 2015 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference
Autore/i: Belardinelli, Pierpaolo; Lenci, Stefano
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269427

Modeling and Analysis of an Electrically Actuated Microbeam Based on Nonclassical Beam Theory
JOURNAL OF COMPUTATIONAL AND NONLINEAR DYNAMICS
Autore/i: Belardinelli, P.; Lenci, Stefano; Brocchini, Maurizio
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/155109

Fluid damping phenomena in a slender microbeam modelled on nonclassical theory
MATEC Web of Conferences
Autore/i: Belardinelli, Pierpaolo; Lenci, Stefano; Cocchi, Giammichele
Editore: EDP Sciences
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/229878

A comparison of different semi-analytical techniques to determine the nonlinear oscillations of a slender microbeam
MECCANICA
Autore/i: Belardinelli, Pierpaolo; Lenci, Stefano; Demeio, Lucio
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/209317

Dynamical characteristics of an electrically actuated microbeam under the effects of squeeze-film and thermoelastic damping
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
Autore/i: Belardinelli, Pierpaolo; Brocchini, Maurizio; Demeio, Lucio; Lenci, Stefano
Classificazione: 1 Contributo su Rivista
Abstract: The static and dynamic behavior of a MEMS subjected to thermoelastic and squeeze-film effects is investigated. We analyse the various engineering aspects which interact in a slender fixed–fixed microbeam; major attention is devoted to the modeling of such a multiphysics system, including the mechanical, electrical, thermoelastic and fluid-dynamic properties with their couplings. The static solution is obtained numerically by a finite-difference technique. The variation of the static deflection with respect to the voltage increment, in the presence of geometric nonlinearites, is studied first. Numerical results on the magnitude of thermoelastic damping (TED) and squeeze-film damping are obtained and examined with a parametric analysis. The effect of different relaxation times imposed on the TED, both in pull-in and non pull-in regime, is studied. The squeeze-film damping is modeled by means of the Reynolds equation and the large pressure regime is investigated. We then present a comparison between the different sources of damping, evaluating their relative contribution to the system.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/107262

The Homotopy-Analysis Approach for the Dynamical Study of a Microbeam Modeled on the Basis of the Strain-Gradient Theory
ASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference
Autore/i: Belardinelli, Pierpaolo; Lenci, Stefano
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269425

The Use of the Strain Gradient Elasticity Theory in the Electrically Actuated Microbeam Problem: An Investigation on the Static and the Dynamic Response
ASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference
Autore/i: Belardinelli, Pierpaolo; Lenci, Stefano
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269426

Dynamics of a Micro Electrical Mechanical System Subject to Thermoelastic and Squeeze-Film Damping
CSNDD 2012 - INTERNATIONAL CONFERENCE ON STRUCTURAL NONLINEAR DYNAMICS AND DIAGNOSIS
Autore/i: Belardinelli, Pierpaolo; Brocchini, Maurizio; Demeio, Lucio; Lenci, Stefano
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/107263