摘要:

AbstractAnalysis in the frequency domain using discrete Fourier transforms is an efficient means of calculating the dynamic response of linear systems. In fact, for systems with frequency dependent parameters and also in those cases where the complex frequency response functions are more easily determined, frequency domain analysis may be the only effective means of determining the dynamic response. The use of discrete transforms along with finite summation requires that the forcing function and the impulse function be converted into periodic forms. This modification may introduce unacceptable errors in the results of analysis, unless appropriate steps are taken to avoid or minimize the effect of aliasing or overlapping. For single‐degree‐of‐freedom systems, procedures that will eliminate the effect of aliasing have already been developed. However, problems related to frequency domain analysis still exist for multi‐degree‐of‐freedom systems with non‐proportional damping, in analysis through substructuring and in those cases where a continuum solution is involved. A new procedure which addresses these problems and is applicable to both single‐ and multi‐degree‐of‐freedom system as well as to analysis through substructur

ISSN:0098-8847    

DOI:10.1002/eqe.4290220102

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractA small‐scale model of an existing cable‐stayed bridge has been designed and built. Hammer, sinusoidal and random signal tests have been performed to determine the dynamic characteristics of the model. An attempt has been made to evaluate the real effect of the vibration of stays upon system damping. Initial measurements have been performed for a model where there was no vibration of the stays because of the absence of appropriately scaled additional mass of these stays. In this way the effect of the cables was eliminated in damping measurement. During the second series of measurements appropriate mass has been added to the stays, causing them to take part in the vibration. The comparison of the measured damping of the model for each case makes possible the estimation of the effect of the stays upon the system damping. By using the shaking table, two types of seismic excitation were applied, with corresponding response quantities in the critical sections being measured. Good agreement between the analytical and the experimental results was achie

ISSN:0098-8847    

DOI:10.1002/eqe.4290220103

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractIn a bounded domain elasto‐plastic wave propagation can be modelled accurately using the finite‐element method. As is even the case for an elastic analysis, an unbounded domain, e.g. a semi‐infinite soil or fluid, can, however, not be represented in this manner, as any spatial discretization has to be avoided. For one‐dimensional wave propagation with a bi‐linear elasto‐plastic material law involving one stress component an analytical solution exists. The latter is used in modelling the non‐linear far field of an unbounded medium using a rigorous bookkeeping procedure of the generated elastic and plastic waves propagating in both directions. The need for a non‐linear model of the far field arises, as in a two‐dimensional representation of soil‐structure interaction the surface

ISSN:0098-8847    

DOI:10.1002/eqe.4290220104

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractMultiple Tuned Mass Dampers (MTMD's) consisting of many tuned mass dampers (TMD's) with distributed natural frequencies are considered for suppressing effectively the harmonically forced single mode response of structures. The fundamental characteristics of MTMD's are investigated analytically with the parameters of the covering frequency range of MTMD's, the damping ratio of each TMD and the total number of TMD's. The effectiveness and the robustness of MTMD's are also discussed in comparison with those of the usual single TMD. It is found that there exists an optimum MTMD for the given total number of TMD's with the optimum frequency range and the optimum damping ratio and that the optimum MTMD is more effective than the optimum single TMD. As for the robustness, it is also clarified that a MTMD can be much more robust than a single TMD while keeping the same level of effectiveness as the optimum single TMD.

ISSN:0098-8847    

DOI:10.1002/eqe.4290220105

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractAn efficient numerical algorithm is developed to solve the quadratic eigenvalue problems arising in the dynamic analysis of damped structural systems. The algorithm can even be applied to structural systems with non‐symmetric matrices. The algorithm is based on the use of Arnoldi's method to generate a Krylov subspace of trial vectors, which is then used to reduce a large eigenvalue problem to a much smaller one. The reduced eigenvalue problem is solved and the solutions are used to construct approximate solutions to the original large system. In the process, the algorithm takes full advantage of the sparseness and symmetry of the system matrices and requires no complex arithmetic, therefore, making it very economical for use in solving large problems. The numerical results from test examples are presented to demonstrate that a large fraction of the approximate solutions calculated are very accurate, indicating that the algorithm is highly effective for extracting a number of vibration modes for a large dynamic system, whether it is lightly or heavily dampe

ISSN:0098-8847    

DOI:10.1002/eqe.4290220106

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThis study investigated the performance, in the frequency domain, of an engineering equivalent linear method that is widely used in soil dynamics. A stochastic linear method using an extended differential equation by Wen and Baber was employed as the base line for evaluation. Stationary responses of single‐degree‐of‐freedom non‐linear systems under filtered white noise from both approaches were compared. For both a smooth nearly elasto‐plastic material and soils, the study found that the engineering equivalent linear analysis underestimated rms displacements, but provided good estimates of rms acceleration responses. Furthermore, the frequency response functions of acceleration from both approaches were close at all levels of

ISSN:0098-8847    

DOI:10.1002/eqe.4290220107

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290220108

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290220109

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0098-8847    

DOI:10.1002/eqe.4290220101

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY