ISSN:1122-8385    

DOI:10.1002/stc.4300070201

出版商:John Wiley&Sons, Ltd    

年代:2000

数据来源: WILEY

摘要:

AbstractThe limiting control possibilities of multi‐mass flexible systems subjected to disturbances from a certain class are studied. A general method of estimating these possibilities is suggested. This method is discussed for the systems described by the ordinary differential equations. The relationship between estimating limiting control possibilities and calculating optimal control with respect to a criterion of minimal guaranteed result is discussed. The mathematical models presented in this paper can be applied to a wide class of actual flexible systems, in particular, to buildings and structures under seismic or wind load

ISSN:1122-8385    

DOI:10.1002/stc.4300070202

出版商:John Wiley&Sons, Ltd    

年代:2000

数据来源: WILEY

摘要:

AbstractFor stability investigations of elastic structures subjected to parametric excitations by white noise we follow Khas'minskii's concept introducing projections on unit hyperspheres which separate all stationary solutions of the linear systems from their instationary part. The projection processes are investigated by Monte‐Carlo simulations and by Fourier expansions of the associated Fokker‐Planck equations in order to obtain the invariant measures of the systems and corresponding top Lyapunov expone

ISSN:1122-8385    

DOI:10.1002/stc.4300070203

出版商:John Wiley&Sons, Ltd    

年代:2000

数据来源: WILEY

摘要:

AbstractIn the present paper, spatially distributed self‐sensing layers with an axially varying intensity of piezoelectric activity are studied within the context of an electromechanically coupled theory for plane flexural deformations of slender smart beams. The main purpose of our derivations is to find shape functions for a piezoelectric self‐sensing layer such that quasi‐static deflections due to known external forces can be exactly annihilated by the piezoelectric actuation. It is shown that shape functions corresponding to the bending moment distributions due to these external forces do represent solutions of this static shape control problem. In the context of self‐sensing layers, the shaped actuator can be also used as a collocated sensor, which is discussed in detail in the present paper. If the span‐wise distribution of the external forces is not known, it may be useful to design self‐sensing layers with the purpose of controlling the deflection at specific locations of the beam axis by means of shape functions with a particularly simple form. Such a concept is also presented. Furthermore, we make reference to so‐called nilpotent shape functions which are neither able to produce actuating effects nor to measure deflections of the beam. The presented theoretical findings are demonstrated for one‐span beams with various boun

ISSN:1122-8385    

DOI:10.1002/stc.4300070204

出版商:John Wiley&Sons, Ltd    

年代:2000

数据来源: WILEY

摘要:

AbstractThe paper studies the dynamic responses of a mdf structure with a one‐side motion limiter. The system in question consists of a base ( a primary structure) impacting on a rigid limiting stop. Such a system exhibits complicated nonlinear dynamics even if the system without limiters is linear. We suppose that the effect of impacts on the motion of the base is much higher than the effect of the interaction between the base and the secondary structure. The mathematical model is thus reduced to a weakly coupled linear structure subjected to both random forces and impact loading. In this work we develop a special decomposition approach to analysis and control problems. As a result, we obtain the approximate representation of the motion of the base as a periodic motion with a slowly varying random envelope. The necessary characteristics of the motion (mean value, variance etc.) are calculate

ISSN:1122-8385    

DOI:10.1002/stc.4300070205

出版商:John Wiley&Sons, Ltd    

年代:2000

数据来源: WILEY

摘要:

AbstractThe elements of the vibroprotection or seismoprotection systems (springs and dampers) undergo the processes of fatigue and aging. This entails the slow evolution of the systems parameters and results in the change of dynamical properties and the loss of the system performance. The paper develops the procedure of the modal identification of a linear base‐isolated structure with slow evolutionary parameters.The identification procedure starts from a time‐series representation of free transient vibration of a linear base isolated structure. The dynamical matrix of a linear system with constant parameters is defined from these time‐series by the Prony method. In this paper we extend the Prony method to systems with random loading and to systems with slow‐evolutionary parameters and propose the procedure of the approximate identification and estimation of the dynamical matrices. The numerical example of the two mass/string base isolated structure with dampers is con

ISSN:1122-8385    

DOI:10.1002/stc.4300070206

出版商:John Wiley&Sons, Ltd    

年代:2000

数据来源: WILEY

摘要:

AbstractThe problem of quasi‐optimal linear feedback control laws for nonlinear systems with quadratic performance criteria under Gaussian white noise excitations is considered. To determine the quasi‐optimal control a modified version of standard iterative procedure is used, where three versions of statistical linearization methods and true linearization method were combined with the optimal control method for linear systems with the mean‐square criterion. The validity of this method is shown by analytical and numerical calculations for exa

ISSN:1122-8385    

DOI:10.1002/stc.4300070207

出版商:John Wiley&Sons, Ltd    

年代:2000

数据来源: WILEY

ISSN:1122-8385    

DOI:10.1002/stc.4300070208

出版商:John Wiley&Sons, Ltd    

年代:2000

数据来源: WILEY

ISSN:1122-8385    

DOI:10.1002/stc.4300070209

出版商:John Wiley&Sons, Ltd    

年代:2000

数据来源: WILEY

ISSN:1122-8385    

DOI:10.1002/stc.4300070210

出版商:John Wiley&Sons, Ltd    

年代:2000

数据来源: WILEY