M Rezaei - MSc Student
M Poursina - Assistant Professors, Faculty of Engineering, University of Isfahan, Isfahan, ۸۱۷۴۶-۷۳۴۴۱, Iran
E Tavakoli - PhD student, Department of Mechanical Engineering, Iran University of Science & Technology, Narmak, ۱۶۸۴۶۱۳۱۱۴, Tehran, Iran,
A Ariaei - Assistant Professors, Faculty of Engineering, University of Isfahan, Isfahan, ۸۱۷۴۶-۷۳۴۴۱, Iran

The goal of this research is vibration damping of an optical device. This study considers the modeling and identification of a nonlinear hysteretic system, wire-rope isolator. A shock and vibration absorber commonly used in naval vessel and airplanes is the wire-rope spring. Wire rope springs show a good damping performance due to rubbing and sliding friction between the wire rope strands. Cyclic loading quasi static tests are carried out on a wire-rope isolator in order to experimentally obtain its hysteretic behavior using simple tensile/compression equipments. The wire-rope isolator exhibits asymmetric hysteresis loop, which posses a hardening loading overlap in the loading curves. The Bouc-Wen model is a nonlinear hysteresis model on a phenomenological base that is one of the most accepted smoothly varying differential models in the engineering field. Because of overlapping and time-history-dependent of the hysteresis force a modified version of the original Bouc-Wen model is presented. An optimization problem is formulated in order to identify the model parameters from the experimental data of the quasi static tests using Genetic Algorithm. Finally, the dynamic response behavior of a wire-rope isolation system is evaluated. In order to reduce the vibration amplitude, type and number of wire-rope isolator can be changed.

vibration isolator, hysteresis, nonlinear modeling, identification, dynamic response