THE FORMATION OF VISCOUS DAMPING MATRICES FOR THE DYNAMIC ANALYSIS OF MDOF SYSTEMS

1996 ◽  
Vol 25 (7) ◽  
pp. 689-709 ◽  
Author(s):  
A. FERIANI ◽  
F. PEROTTI
Keyword(s):  
Dynamic Analysis ◽  
Viscous Damping ◽  
Mdof Systems

Dynamic Analysis of Flapper/Nozzle Electrohydraulic Servovalve Considering the Influence of the First-Stage Parameters

2014 ◽  
Vol 687-691 ◽  
pp. 316-321
Author(s):  
Wei Zhang ◽  
Song Jing Li
Keyword(s):  
Dynamic Response ◽  
Dynamic Analysis ◽  
Simulation Model ◽  
Discharge Coefficient ◽  
Mathematic Model ◽  
Viscous Damping ◽  
Response Characteristics ◽  
The Past ◽  
Simulation Results ◽  
Dynamic Response Characteristics

The mathematic model of flapper/nozzle electrohydraulic servovalves is rearranged, many factors are reconsidered which have been omitted in the past analysis which are for the purposes of convenience or on the assumption that they are of no particular significance. According to the rearranged mathematic model, the simulation model of the servovalve is established using the Matlab/simulink software, dynamic response characteristics of the servovalve is simulated when the parameters of the discharge coefficient of nozzles and the viscous damping constant of torque motor and flapper are changed. Simulation results show that the change of the parameters influence the dynamic response of the spool displacement.

Free Vibration of MDOF Systems with Nonperiodically Time-Varying Mass

2018 ◽  
Vol 18 (06) ◽  
pp. 1850077
Author(s):  
Seyed Mojtaba Hozhabrossadati ◽  
Ahmad Aftabi Sani
Keyword(s):  
Free Vibration ◽  
Variable Mass ◽  
Coupled System ◽  
Variable Coefficients ◽  
Time Variable ◽  
Viscous Damping ◽  
Transform Method ◽  
Constant Stiffness ◽  
Mdof Systems ◽  
Mass Spring

This paper deals with the free vibration response of MDOF mass-spring systems with time-variable mass and constant stiffness. To show the necessity of this study, a review on the related published articles is presented. After formulating the governing initial value problem which is a coupled system of differential equations with variable coefficients, the differential transform method (DTM) is employed to obtain an analytical solution. The proposed solutions are verified against exact results available in the literature. It is demonstrated that the effect of time-variable mass is equivalent to viscous damping. This viscous damping can be positive or negative depending on the sign of the mass change rate. This role is thoroughly investigated via numerical examples.

scholarly journals Effect of Damping and Yielding on the Seismic Response of 3D Steel Buildings with PMRF

2014 ◽  
Vol 2014 ◽  
pp. 1-21 ◽  
Author(s):  
Alfredo Reyes-Salazar ◽  
Achintya Haldar ◽  
Ramon Eduardo Rodelo-López ◽  
Eden Bojórquez
Keyword(s):  
Seismic Response ◽  
Three Dimensional ◽  
Lateral Force ◽  
Viscous Damping ◽  
Steel Buildings ◽  
Local Response ◽  
Equivalent Viscous Damping ◽  
Response Parameter ◽  
Mdof Systems ◽  
Crude Approximation

The effect of viscous damping and yielding, on the reduction of the seismic responses of steel buildings modeled as three-dimensional (3D) complex multidegree of freedom (MDOF) systems, is studied. The reduction produced by damping may be larger or smaller than that of yielding. This reduction can significantly vary from one structural idealization to another and is smaller for global than for local response parameters, which in turn depends on the particular local response parameter. The uncertainty in the estimation is significantly larger for local response parameter and decreases as damping increases. The results show the limitations of the commonly used static equivalent lateral force procedure where local and global response parameters are reduced in the same proportion. It is concluded that estimating the effect of damping and yielding on the seismic response of steel buildings by using simplified models may be a very crude approximation. Moreover, the effect of yielding should be explicitly calculated by using complex 3D MDOF models instead of estimating it in terms of equivalent viscous damping. The findings of this paper are for the particular models used in the study. Much more research is needed to reach more general conclusions.

scholarly journals Effect of the viscous damping on the seismic response of Low-rise RC frame building

2020 ◽  
pp. 32-43
Author(s):  
Fatima Zohra Baba-Hamed ◽  
Luc Davenne
Keyword(s):  
Reinforced Concrete ◽  
Damage Index ◽  
Time History ◽  
Time History Analysis ◽  
Nonlinear Time History Analysis ◽  
Viscous Damping ◽  
Rc Frame ◽  
History Analysis ◽  
Mdof Systems ◽  
Nonlinear Time History

The equivalent viscous damping is a key parameter in the prediction of the maximum nonlinear response. Damping constitutes a major source of uncertainty in dynamic analysis. This paper studies the effect of using viscous damping, on the reduction of the seismic responses of reinforced concrete RC frame buildings modeled as three-dimensional multi degree of freedom (MDOF) systems, and the use of nonlinear time history analysis as a method of visualized behavior of buildings in the elastic and inelastic range. This study focuses on the implications of the available modeling options on analysis. This article illustrates the effect of using the initial or tangent stiffness in Rayleigh damping in analysis of structures.  Correspondingly, this work is also concerned with the estimation of Rayleigh, mass-proportional or stiffness-proportional damping on engineering demand parameters (EDPs). As a result of a series of considerations, a damping modeling solution for nonlinear time history analysis (NLTHA) was carried out to compute the damage index. The application example is a building designed according to reinforced concrete code BAEL 91 and Algerian seismic code RPA 99/Version 2003 under seven earthquake excitations. The simulations demonstrated the accuracy and effectiveness of the proposed method to account for all of the above effects.

Sign in / Sign up

Export Citation Format

Share Document