Vibration amplification in oscillating systems with degrading characteristics

Abstract

The paper is an analysis of the dynamic response of an oscillating system, considering the modifications of the stiffness and damping characteristics, due to the vibration – generated damages. The study is focused on the difference in the system behavior, function of the way the system is initially situated relative to the harmonic input from the spectral point of view: above resonance, at resonance or below resonance. Experimental and simulation results are presented for simplified mechanical models of systems with stiffness degradation. As a convenient measure of the effect of duration and severity of the system vibration, the total energy dissipated through hysteresis is considered. It is shown that the most damaging situation occurs when the forcing frequency is slightly less than the system natural frequency. In this case, in a very short time interval from the start of the input action, the system displays a severe vibration output, which can lead to structural deterioration.