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Reduced-Order Modeling, Testing, and Control of Nonlinear Mechanical and Structural Systems

José Manoel Balthazar, Paulo Batista Gonçalves, Angelo Marcelo Tusset, Grzegorz Litak, Livija Cveticanin
2017 Shock and Vibration  
This special issue addresses the general problem of model size reduction for describing nonlinear vibration of structural elements and systems. The aim is to provide and analyze tools that allow accurately capturing nonlinear dynamic behavior using a minimal number of degrees of freedom. It involves modeling and control of nonlinear dynamical phenomena in structural systems and other complex multibody mechanisms. The problems discussed involve identification and control of nonlinear systems as
more » ... nlinear systems as well as responses of the nonlinear system under cyclic excitations. The problem is related to the dimensionality of the nonlinear system which could be a measure of complexity. It is worth noticing that in nonlinear systems there are a variety of multiple solutions which, together with a synchronization phenomenon, play basic and many times competing roles. In some of the systems, for example, the systems showing stick and slip phenomenon, due to dry friction, the dimensionality varies in time. On the other hand, nonlinear systems with memory are characterized by long transients which strongly influence the dynamics identification control procedure. Such a memory effect is frequently observed as a hysteretic behavior based on appearing additional degrees of freedom and can be modeled with a fractional derivative. Finally, the material, structural, and multibody interaction nonlinearities can lead to localized effects which increase the system complexity but the particular response of the dynamical system can be described by a size reduced model. The authors of one of the papers study the chaotic oscillations in a fractional order model of a portal frame with nonideal loading. The bifurcation of the fractional order portal frame system for parameters and fractional orders are investigated. Adaptive sliding mode controllers are designed to suppress the chaotic oscillations with uncertain parameters. In another paper, the authors predict the pullout capacity of small ground anchors using nonlinear computing techniques. Results show that the developed prediction models enhance the precision of predicting the pullout capacity when compared with previous studies. In one of the papers, in order to investigate the seismic damage of cable-stayed bridges, a scaled model of a single-tower cable-stayed bridge with A-shaped tower was designed, constructed, and tested on shake tables. Experimental and simplified numerical analysis show the correspondence with fairly small error. One of the papers is dealing with dynamic nonlinear responses and stability of slender structures in the main resonance regions. In this paper, an incremental technique for direct calculation of the nonlinear response in frequency domain of plane frames subjected to base excitation was proposed. In another paper a control methodology is applied to an automated manual transmission vehicle for drivability enhancement Hindawi
doi:10.1155/2017/9232878 fatcat:dzmzxsa3bzcaroy7pzhfysbafy