Journal of Structural Dynamics
https://popups.uliege.be/26846500
fr

Sequential Bayesian Inference for Uncertain Nonlinear Dynamic Systems: A Tutorial.
https://popups.uliege.be/26846500/index.php?id=107
In this article, an overview of Bayesian methods for sequential simulation from posterior distributions of nonlinear and nonGaussian dynamic systems is presented. The focus is mainly laid on sequential Monte Carlo methods, which are based on particle representations of probability densities and can be seamlessly generalized to any statespace representation. Within this context, a unified framework of the various Particle Filter (PF) alternatives is presented for the solution of state, stateparameter and inputstateparameter estimation problems on the basis of sparse measurements. The algorithmic steps of each filter are thoroughly presented and a simple illustrative example is utilized for the inference of i) unobserved states, ii) unknown system parameters and iii) unmeasured driving inputs.
Mon, 21 Mar 2022 00:00:00 +0100
https://popups.uliege.be/26846500/index.php?id=107

Computational Modeling of Nonlinear Dynamics and Its Utility in MEMS Gyroscopes.
https://popups.uliege.be/26846500/index.php?id=96
This paper describes a hybrid approach for modeling nonlinear vibrations and determining essential (normal form) coefficients that govern a reducedorder model of a structure. Incorporating both computational and analytical tools, this blended method is demonstrated by considering a microelectromechanical vibrating gyroscopic rate sensor that is actuated by segmented DC electrodes. Two characterization methods are expatiated, where one is more favorable in computational tools and the other can be used in experiments. Using the reduced model, it is shown that tuning the nonuniform DC bias results in favorable changes in Duffing and modecoupling nonlinearities which can improve the gyroscope angular rate sensitivity by two orders of magnitude.
Fri, 04 Mar 2022 00:00:00 +0100
https://popups.uliege.be/26846500/index.php?id=96

Normal form transformations for structural dynamics: An introduction for linear and nonlinear systems.
https://popups.uliege.be/26846500/index.php?id=84
The aim of this paper is to provide an introduction to using normal form transformations for linear and nonlinear structural dynamics examples. Starting with linear singledegreeoffreedom systems, a series of examples are presented that eventually lead to the analysis of a system of two coupled nonlinear oscillators. A key part of normal form transformations are the associated coordinate transformations.This review includes topics such as Jordan normal form and modal transformations for linear systems, while for nonlinear systems, nearidentity transformations are discussed in detail. For nonlinear oscillators, the classical methods of PoincarĂ© and Birkhoff are covered, alongside more recent approaches to normal form transformations. Other important topics such as nonlinear resonance, bifurcations, frequency detuning and the inclusion of damping are demonstrated using examples. Furthermore, the connection between normal form transformations and Lie series is described for both first and secondorder differential equations. The use of normal form transformations to compute backbone curves is described along with an explanation of the relationship to nonlinear normal modes. Lastly, conclusions and possible future directions for research are given.
Mon, 17 Jan 2022 00:00:00 +0100
https://popups.uliege.be/26846500/index.php?id=84

Contact modeling across scales: from materials to structural dynamics applications.
https://popups.uliege.be/26846500/index.php?id=72
The study of contact is an engineering pursuit that spans multiple disciplines and scales. Structural dynamics, as well as aspects of nonlinear dynamics and vibrations, is concerned with contact in systems at the macroscale. At the microscale, tribology is concerned with the evolution of two surfaces in contact in terms of frictional and wear behavior. Between these two scales, solid mechanics investigates the development of stresses within two bodies due to contact through elasticity and plasticity solutions (amongst other methods). Lastly, contact research within material science investigates the interaction of grains and the evolution of a material's structure due to impact and other damaging events. These four fields, structural dynamics, solid mechanics, tribology, and material science, are traditionally separate even though they are each concerned with interfaces and the contact of two bodies. By integrating all four fields, new opportunities for advancing the understanding of contact emerge. In this paper, open challenges and potential paths forward for future directions in contactbased research is discussed.
Mon, 13 Dec 2021 00:00:00 +0100
https://popups.uliege.be/26846500/index.php?id=72

Comparison of passive damping treatments based on constrained viscoelastic layers and multiresonant piezoelectric networks.
https://popups.uliege.be/26846500/index.php?id=63
This work aims at comparing the damping performances of two passive damping treatments based on piezoelectric or viscoelastic patches. The motivation for such a comparison stems from the fact that the two damping techniques have been developed fairly independently, and are rarely compared. First, the dynamic response of a simplysupported metallic plate is measured experimentally after being equipped with constrained viscoelastic patches or piezoelectric patches connected to an electrical network. In order to extend the comparison, a numerical model of the structure is set up and validated to evaluate the damping performances of both passive treatments under different configurations (for instance equalmass and equalthickness configurations). Finally, with regard to these experimental and numerical results, the advantages and the limitations in using viscoelastic or piezoelectric treatments are discussed.
Tue, 14 Sep 2021 00:00:00 +0200
https://popups.uliege.be/26846500/index.php?id=63

Damping of coupled bendingtorsion beam vibrations by a twodof tmd with analogous coupling
https://popups.uliege.be/26846500/index.php?id=56
Coupled bendingtorsion vibrations of a beam with a single crosssection axis of symmetry are mitigated by a twodegreeoffreedom (dof) tuned mass damper with a coupling analogous to that of the beam. By modal truncation a fourdegreeoffreedom model is derived for tmd tuning. Because of the analogous tmd properties, a stiffness tuning formula identical to that for the classic tuned mass damper secures inverse relations between all four undamped natural frequencies. Expressions for the tmd damping are subsequently found by a numerical search, which maximizes the smallest of the four damping ratios, resulting in equal damping in three of the four modes. The twodof coupled tmd is finally assessed by numerical root locus and frequency response analysis for a full flexible beam.
Thu, 01 Jul 2021 00:00:00 +0200
https://popups.uliege.be/26846500/index.php?id=56