Structural Dynamics of Mechanical Systems with Local Nonlinearities under Periodic Excitation

1993 ◽  
pp. 261-268
Author(s):  
D. H. van Campen ◽  
R. H. B. Fey ◽  
A. de Kraker
Keyword(s):  
Structural Dynamics ◽  
Mechanical Systems ◽  
Periodic Excitation

scholarly journals A New Design of Vibration Absorber for Periodic Excitation

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Shyh-Chin Huang ◽  
Kao-An Lin
Keyword(s):  
Mechanical Systems ◽  
Harmonic Excitation ◽  
Design Parameters ◽  
Vibration Absorber ◽  
Periodic Excitation ◽  
Dynamic Vibration Absorber ◽  
Dual Beam ◽  
Design Variables ◽  
Resonance Frequencies ◽  
Engineering Significance

The authors designed a novel type of dynamic vibration absorber, called periodic vibration absorber (PVA), for mechanical systems subjected to periodic excitation. Since the periodic rather than single harmonic excitation is themost occurring case in mechanical systems, the design of PVA is hence of engineering significance. The PVA designed in this paper is composed of a dual-beam interconnected with a discrete spring in between. By appropriately choosing the design parameters, the PVA can be of resonance frequencies in integer multiples of the base frequency such that the PVA can absorb significant amount of higher harmonics in addition to the base harmonic. The designed PVA was first experimentally verified for its resonance frequencies. The PVA implemented onto a mechanical system was then tested for its absorption ability. From both tests, satisfying agreement between experiments and numerical calculations has been obtained. The sensitivities of the design variables, such as the discrete spring’s stiffness and location, were discussed as well. The parameters’ sensitivities provided us with the PVA’s adjustable room for excitation frequency’s mismatch. Numerical results showed that within 3% of frequency mismatch, the PVA still performed better than a single DVA via adjusting the spring’s constant and location. All the results proved that the novel type of PVA could be a very effective device for vibration reduction of mechanical systems subjected to periodic excitation.

Control of chaos: methods and applications in mechanics

2006 ◽  
Vol 364 (1846) ◽  
pp. 2279-2307 ◽  
Author(s):  
Alexander L Fradkov ◽  
Robin J Evans ◽  
Boris R Andrievsky
Keyword(s):  
Adaptive Control ◽  
Feedback Control ◽  
Chaotic Systems ◽  
Mechanical Systems ◽  
Periodic Excitation ◽  
Control Of Chaos ◽  
Control Engineering ◽  
Delayed Systems ◽  
Spatio Temporal ◽  
Time Delayed Feedback

A survey of the field related to control of chaotic systems is presented. Several major branches of research that are discussed are feed-forward (‘non-feedback’) control (based on periodic excitation of the system), the ‘Ott–Grebogi–Yorke method’ (based on the linearization of the Poincaré map), the ‘Pyragas method’ (based on a time-delayed feedback), traditional for control-engineering methods including linear, nonlinear and adaptive control. Other areas of research such as control of distributed (spatio-temporal and delayed) systems, chaotic mixing are outlined. Applications to control of chaotic mechanical systems are discussed.

Research on Wind Turbine Blade Load Based on the Analysis of Structural Dynamics

2014 ◽  
Vol 1022 ◽  
pp. 147-150
Author(s):  
Zhi Qiang Xu
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Structural Dynamics ◽  
Environmental Science ◽  
Mechanical Systems ◽  
Fatigue Loading ◽  
Wind Turbine Blade ◽  
Stochastic Dynamic ◽  
Strong Wind ◽  
Wide Range

Wind energy technology is an integrated technology, which involves aerodynamics, structural dynamics, meteorology, mechanical engineering, electrical engineering, control multiple disciplines technology, materials science, environmental science and other areas. This paper studies the structural dynamics of the wind turbine. On one hand, modern wind turbine is composed of various interacting components and subsystems, and its aerodynamic rotor design technique involves controlling a wide range of areas systems, mechanical systems, electrical systems. On the other hand, the wind turbine has characteristics different from the usual mechanical systems. Wind turbine power source is natural randomness of strong wind, The leaves are often run in a stall condition. The system has a strong stochastic dynamic process. The transmission system irregular power input is abnormal . The main structural components exposed to several times higher than normal rotating mechanical fatigue loading. Thus the unique characteristic of dynamics of the wind turbine is formed . Analysis of wind turbine blade load dynamics of basic research carried out in this article by means of an appropriate structure coordinates.

Long Term Structural Dynamics of Mechanical Systems With Local Nonlinearities

1996 ◽  
Vol 118 (2) ◽  
pp. 147-153 ◽  
Author(s):  
R. H. B. Fey ◽  
D. H. van Campen ◽  
A. de Kraker
Keyword(s):  
Structural Dynamics ◽  
Degrees Of Freedom ◽  
Mechanical Systems ◽  
Nonlinear Dynamic System ◽  
Complex Dynamic ◽  
Floquet Multipliers ◽  
Beam System ◽  
Linear Spring ◽  
Long Term Behavior

This paper deals with the long term behavior of periodically excited mechanical systems consisting of linear components and local nonlinearities. The number of degrees of freedom of the linear components is reduced by applying a component mode synthesis technique. Lyapunov exponents are used to identify the character of the long term behavior of a nonlinear dynamic system, which may be periodic, quasi-periodic or chaotic. Periodic solutions are calculated efficiently by solving a two-point boundary value problem using finite differences. Floquet multipliers are calculated to determine the local stability of these solutions and to identify local bifurcation points. The methods presented are applied to a beam system supported by a one-sided linear spring, which reveals very rich, complex dynamic behavior.

Structural dynamics of P-type ATPase ion pumps

2019 ◽  
Vol 47 (5) ◽  
pp. 1247-1257 ◽  
Author(s):  
Mateusz Dyla ◽  
Sara Basse Hansen ◽  
Poul Nissen ◽  
Magnus Kjaergaard
Keyword(s):  
Structural Dynamics ◽  
Single Molecule ◽  
New Technologies ◽  
Atp Hydrolysis ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Time Resolved ◽  
Dynamics Simulations ◽  
Types Of Information ◽  
P Type

Abstract P-type ATPases transport ions across biological membranes against concentration gradients and are essential for all cells. They use the energy from ATP hydrolysis to propel large intramolecular movements, which drive vectorial transport of ions. Tight coordination of the motions of the pump is required to couple the two spatially distant processes of ion binding and ATP hydrolysis. Here, we review our current understanding of the structural dynamics of P-type ATPases, focusing primarily on Ca2+ pumps. We integrate different types of information that report on structural dynamics, primarily time-resolved fluorescence experiments including single-molecule Förster resonance energy transfer and molecular dynamics simulations, and interpret them in the framework provided by the numerous crystal structures of sarco/endoplasmic reticulum Ca2+-ATPase. We discuss the challenges in characterizing the dynamics of membrane pumps, and the likely impact of new technologies on the field.

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