摘要:

AbstractThe aim of the work presented here is to provide an accurate prediction of the dynamical behaviour of reversible aerial ropeways. A mechanical and numerical model is developed in order to check the safety of any such ropeway after a haul rope rupture.The whole installation (including carriers, counterweights and ropes) is first given an initial position. The model then simulates the disappearance of some cables and counterweights, and evaluates the subsequent displacements of the remaining parts, excluding track ropes. The model uses very simple first‐order finite elements, accounting for non‐linear effects caused by large displacements. The numerical integration is very efficient, and suits the capabilities of small microcomputers; it does not require matrix inversions, nor stiffness matrix evaluations.A full‐scale experiment has recently been carried out on a ropeway in the French Alps. If a simple kind of viscous damping is accounted for, numerical and experimental results compare with a reasonable accuracy. The present model is now in use for design and control of actual ropeway equi

ISSN:0098-8847    

DOI:10.1002/eqe.4290120402

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractSome equivalent linearization techniques, applicable to problems dealing with non‐linear seismic amplification of layered soils, are systematically treated and critically compared in this paper. The discussion concerns, in particular, the theoretical consistency, the operative modalities, the computational complexity and the numerical reliability of these methods.A comparison is made between the results furnished by some techniques among those examined and the results obtained through a step‐by‐step integration of the non‐linear equations of motion, assuming as a test‐problem the one‐dimensional amplification of a horizontally stratified soil deposit characterized by the Ramberg‐Osgood const

ISSN:0098-8847    

DOI:10.1002/eqe.4290120403

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThis paper considers the response of a beam with a dynamic vibration absorber, which consists of a viscoelastic solid and a double‐cantilever viscoelastic beam, attached to the centre of the main beam. The ends of the main beam are built in and excited sinusoidally by the base motion. The transfer matrix method is used in the analysis. The displacement transmissibility, i.e. the ratio of the displacement at the centre of the main beam to that of the base is investigated in the numerical example. It is shown that the present absorber is effective to suppress several resonances of the main beam simultaneously by only one compact device. Values of the optimum tuning design parameters are presented in the numerical exampl

ISSN:0098-8847    

DOI:10.1002/eqe.4290120404

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractBased on the main features of the computer program THGE, the paper reviews the techniques which are available for the construction of an accelerogram whose response spectrum matches a design spectrum. First, a sample accelerogram is generated as the product of the stationary random sequence by a deterministic shape function. It is assumed that the spectral properties of the stationary process have been determined in a previous step, in order to lead to the design spectrum as expected maximum responses of a set of single degree of freedom oscillators. The principal properties of the Fast Fourier Transform which is used for this first step are reviewed. The paper then describes the procedures which are available, both in the frequency domain and in the time domain, to improve the agreement between the response spectrum and the target. It also discusses some related issues, such as the response spectrum calculations, the statistical dependence between the three earthquake components, the duration of the time history, the variability of the secondary response to various samples and the generation of an accelerogram whose response spectra envelop a set of design spectra. The point of view adopted is the one of the structural engineer.

ISSN:0098-8847    

DOI:10.1002/eqe.4290120405

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThe accuracy of a numerical method is demonstrated for the dynamic analysis of large complex finite element systems in which the spatial distribution of the loading is constant. The method is based on the use of a special class of Ritz vectors which were previously proposed and can be generated with minimum numerical effort. The purpose of this paper is to extend the use of these vectors to the solution of wave propagation and foundation response problems.The method is applied to one‐, twoand three‐dimensional problems in order to illustrate the efficiency and accuracy of the technique. Unless it is necessary to evaluate the very high‐frequency behaviour of a structural system, it is shown that a small number of Ritz vectors will produce excellent results. Therefore, they can be very effective in the solution of three‐dimensional soil‐structure systems subjected to earthquak

ISSN:0098-8847    

DOI:10.1002/eqe.4290120406

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractA complex response algorithm for the dynamic analysis of axisymmetric thin shells supported on an interactive foundation is developed. The substructure deletion method is employed through the utilization of a dynamic boundary system at the contact area between the superstructure and the substructure. A new mathematical formulation in conjunction with the shell behaviour is developed to deal with rigid body motions due to the negation of the fixed base assumption. Four foundation conditions, that is, a fixed base, two pile foundation cases and a flexible base, are to examine the effect of base flexibility on the seismic response of cooling towers. Also, excellent comparative results between the frequency domain solution and a time domain solution are obtained.

ISSN:0098-8847    

DOI:10.1002/eqe.4290120407

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractAfter reviewing briefly a recently proposed procedure for evaluating the dynamic transient response of a classically damped linear system from its corresponding steady‐state response, a modified procedure is presented which also appears to be highly efficient for non‐classically damped systems of the type encountered in studies of soil‐structure interaction. The concepts involved are developed by reference to viscously damped single‐degree‐of‐freedom systems, and numerical solutions are included to illustrate the accuracy and efficiency of the proposed procedure and its superiority over the classical Discrete Fourier Transfo

ISSN:0098-8847    

DOI:10.1002/eqe.4290120408

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractRecordings of recent strong earthquakes obtained on alluvial sites show that the maximum horizontal accelerations tend towards a limit of about 0.45 to 0.50g, associated with large displacements. by contrast, vertical accelerations do not appear to be subject to such a limit (1.7g for the 1979 Imperial Valley earthquake). Theoretical linear elasticity models, when applied to superficial layers of low strength, seem to be inadequate for the prediction of near‐field ground motions in alluvial deposits. A good approximation for the horizontal component of certain Imperial Valley records was, however, obtained through a non‐linear approach, using local soil properties together with a reasonable hypothesis for motion at the base of the superficial layers in question that included large values of acceleration for high‐frequency shear

ISSN:0098-8847    

DOI:10.1002/eqe.4290120409

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractA procedure for deriving the Lanczos vectors is explained and their use in structural dynamics analysis as an alternative to modal co‐ordinates is discussed. The vectors are obtained by an inverse iteration procedure in which orthogonality is imposed between the vectors resulting from successive iteration cycles. Using these Lanczos vectors the equations of motion are transformed to tridiagonal form, which provides for a very efficient time‐stepping solution. The effectiveness of the method is demonstrated by a numerical exam

ISSN:0098-8847    

DOI:10.1002/eqe.4290120410

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290120411

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY