טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentAlloni Aviv
SubjectDynamics of Forced System with Vibro Impact Energy Sink
DepartmentDepartment of Mechanical Engineering
Supervisor Professor Oleg Gendelman
Full Thesis textFull thesis text - English Version


Abstract

A Nonlinear Energy Sink (NES) is widely studied as a mean for mitigation of undesired vibrations. The NES is a passive isolation device which is basically composed of a structural element with relatively small mass and relatively weak dissipation, coupled to a primary system and aiming to absorb its energy via essentially nonlinear coupling. The NES is designed to be activated when the energy in the system exceeds a certain threshold. To date a variety of designs of the NESs have been suggested

            In this thesis we considered a mitigation of steady-state external forcing by means of a vibro-impact NES. Vibro-impact NES is presented through a simple model of a straight cavity in the primary mass, in which an impacting particle is allowed to move freely. The impacts with the cavity restraints are considered in the framework of a Newton non-elastic model.

In order to solve the system analytically we use the multiple-scales method which enables investigation of "slow" and "super-slow" time scales. We deduced that the system can have two different response regimes that depend on the forcing amplitude. One of these possible regimes is steady-state resonant response; the other is a novel type of chaotic strongly modulated response (CSMR). The latter becomes possible due to special structure of a slow invariant manifold of the problem, possessing only one stable and one unstable branch. These results were confirmed by numeric simulations.