Analysis of the Dynamic Behavior of the Antiseismic Elastomeric Isolators Based on the Evaluation of the Internal Dissipated Energy

Abstract:

The method of testing the elastomeric isolators at shearing, in a system formed of two elements in parallel, is presented. The exterior actions can be represented by harmonic functions defined as:kinematic excitation through the instantaneous displacement of the form (t)=Asinωt;dynamic excitation through the instantaneous force of the form F(t)=F₀sintωt or P(t)=m₀rω²sintωt.The linear viscoelastic behavior of the elastomer enables the obtainment of hysteresis curves of elliptical shape for each harmonic loading.In the end, the dynamic stiffness as well as the equivalent damping can be evaluated, with the mention that the stand testing individualizes the dynamic system only through viscous, elastic and inertial forces. Due to this reason, the 1^st order differential equation eliminates the definition of the critical damping ratio as for a second order system, which leads to the introduction of the concept of equivalent damping, originating in the hysteretic damping or the loss factor.

• Periodical: Applied Mechanics and Materials (Volume 430)
• Pages: 317-322
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.430.317
• Online since: September 2013
• Authors: Carmen Alexandru
• Keywords: Dissipated Energy, Dynamic Excitation, Elastomer, Kinematic Excitation, Loss Factor, Viscoelastic Model

References

[1] W. Baterma, R. Kohler, Elastomere Federung, Verlag von Wilhelm Ernst & Son, Berlin. Mϋnchen, (1982).

[2] P. Bratu, Vibration transmissivity in mechanical systems with rubber elements using viscoelastic models, Proceedings of 5th European Rheology Conference, University of Ljubljana, Slovenia, (1998).

DOI: 10.1007/978-3-642-51062-5_117

[3] P. Bratu, Evaluation of the dissipation effect while performing harmonic dynamic tests upon materials having variable damping characteristics, Proceedings of INTER-NOISE 2007, Istanbul, Turkey, (2007).

[4] Y. Jullien, Réduction des vibrations mècaniques sues aux machines, Colloque RILEM Budapest, (1963).

[5] P. Bratu, N. Drăgan, L'analyse des mouvements désaccouplés appliquée au modèle de solide rigide aux liaisons élastiques, Analele Universitatii Dunarea de Jos, of Galati, Fascicula XIV, (1997).

DOI: 10.35219/im.2017.2.04

[6] P. Bratu, O. Vasile, Modal analysis of viaducts supported on elastomeric insulation within the Bechtel constructive solution for the Transilvania highway, Romanian Journal of Acoustics and Vibration, 9(2012) 77-82.

[7] M. Dolce, FC. Ponzo, A. DiCesare, G. Arleo, Progetto di Edifici con Isolamento Sismico, Iuss Press, Pavia, Italy, (2010).

[8] JP. Bandstra, Comparison of equivalent viscous damping and nonlinear damping in discret and continuous vibrating system, Journal of Mechanisms, Transmissions and Automation in Design, J.V.A.S.R.D., vol I 105, (1983).

DOI: 10.1115/1.3269117

[9] TK. Caughey, MEJ. O'Kelly, Effect of damping on the natural frequencies on linear dynamic systems, Journal of the American Statistical Associating, J.A.S.A., vol. 33, (1961).

[10] I. Cochin, Analysis and Deisign of Dynamic Systems, Harper&Raw, New York, (1980).

[11] S. Rao, Mechanical Vibrations, Addison-Wesley, New York, (1995).

[12] SR EN 15129: 2010, Dispozitive antiseismice, (2010).