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Damping Force (damping + force)

Distribution by Scientific Domains
Engineering100%

Selected Abstracts

Dynamic analysis method of a combined energy dissipation system and its experimental verification

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 6 2002
Xilin Lu
Abstract A combined energy dissipation system is developed in this paper. In this system lead rubber dampers and their parallel connection with oil dampers are used in the braces of a structural frame. A dynamic analysis method of the system, including the modelling of the lead rubber damper and the oil damper, is proposed. In the analysis method, the restoring force characterestics of the lead rubber damper is simulated by the Bouc,Wen hysteretic model, and the behaviour of the oil damper is simulated by a velocity and displacement-related model in which the contributions of the oil damper to the damping force and stiffness of the system are considered. A series of shaking table tests of a three-storey steel frame with the combined energy dissipation system are carried out to evaluate the performance of the system and to verify the analysis method. The test and analysis show that the performance of the combined energy dissipation system is quite satisfactory and there is a good agreement between the analysis and test results, which indicates that the analysis method proposed in this paper is valid and suitable for the dynamic analysis of the combined energy dissipation system. Copyright © 2002 John Wiley & Sons, Ltd. [source]

A mathematical hysteretic model for elastomeric isolation bearings

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 4 2002
J. S. Hwang
Abstract An analytical model for high damping elastomeric isolation bearings is presented in this paper. The model is used to describe mathematically the damping force and restoring force of the rubber material and bearing. Ten parameters to be identified from cyclic loading tests are included in the model. The sensitivity of the ten parameters in affecting the model is examined. These ten parameters are functions of a number of influence factors on the elastomer such as the rubber compound, Mullins effect, scragging effect, frequency, temperature and axial load. In this study, however, only the Mullins effect, scragging effect, frequency and temperature are investigated. Both material tests and shaking table tests were performed to validate the proposed model. Based on the comparison between the experimental and the analytical results, it is found that the proposed analytical model is capable of predicting the shear force,displacement hysteresis very accurately for both rubber material and bearing under cyclic loading reversals. The seismic response time histories of the bearing can also be captured, using the proposed analytical model, with a practically acceptable precision. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Topology optimization for stationary fluid,structure interaction problems using a new monolithic formulation

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 5 2010
Gil Ho Yoon
Abstract This paper outlines a new procedure for topology optimization in the steady-state fluid,structure interaction (FSI) problem. A review of current topology optimization methods highlights the difficulties in alternating between the two distinct sets of governing equations for fluid and structure dynamics (hereafter, the fluid and structural equations, respectively) and in imposing coupling boundary conditions between the separated fluid and solid domains. To overcome these difficulties, we propose an alternative monolithic procedure employing a unified domain rather than separated domains, which is not computationally efficient. In the proposed analysis procedure, the spatial differential operator of the fluid and structural equations for a deformed configuration is transformed into that for an undeformed configuration with the help of the deformation gradient tensor. For the coupling boundary conditions, the divergence of the pressure and the Darcy damping force are inserted into the solid and fluid equations, respectively. The proposed method is validated in several benchmark analysis problems. Topology optimization in the FSI problem is then made possible by interpolating Young's modulus, the fluid pressure of the modified solid equation, and the inverse permeability from the damping force with respect to the design variables. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Model of inelastic impact of unit loads

PACKAGING TECHNOLOGY AND SCIENCE, Issue 1 2009
Tomasz Piatkowski
Abstract In this study, the authors present a model of the inelastic impact of bodies that takes place during handling of unit loads (cubiform parcels). A modified non-linear Kelvin model is proposed, in which the relationships between object strains and elastic and damping forces of the impact are represented by power functions. The results of analytical investigations on the proposed model were confirmed by experiments consisting in tests of free fall of the load on rigid ground and on elastic beam. The developed model allows the assessment of the influence of mechanical properties of loads and conveyor-line deflection mechanisms as well as impact velocity, on the dynamic forces exerted on the manipulated objects during the impact. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Damped vibrations of the beam systems in rotational transportation

PROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2009
kiewskiArticle first published online: 5 MAR 2010
The major aim of this thesis is dynamical analysis of systems in rotational transportation with taking into consideration in the mathematical models the damping forces. The dissipation of energy in form of damping is inseparable connected with motion of analyzed systems. Up to now modelling of rod and beam systems in transportation was very often based on simplification and reduction of damping effect and on the other side the considerations very rarely apply to systems where the transportation effect was took into consideration. In this thesis the dynamical flexibility of the damped beam systems in transportation was presented. Analyzing systems were assumed as simple homogenous beam systems with symmetrical cross-section constant on whole length of the system. Most popular technical applications of such systems are put into use in propellers and sails of wind power plant, main, auxiliary rotors of helicopters, turbines, etc. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]