Eventos Anais de eventos
DINAME 2017
XVII International Symposium on Dynamic Problems of Mechanics
AUTOPARAMETRIC NON-IDEAL SYSTEM AND VIBRATION ENERGY HARVESTING
Submission Author:
Jorge Luis Palacios Felix , RS , Brazil
Co-Authors:
José Manoel Balthazar, Reyolando Brasil, Rodrigo Tumolin Rocha
Presenter: Jorge Luis Palacios Felix
doi://10.26678/ABCM.DINAME2017.DIN17-0121
Abstract
There has been much recent interest on the study of autoparametric vibration absorbers for mechanical structural systems. Small-scale laboratory model were tested to gain understanding of the numerous requirements for optimum performance of these vibration suppression devices. They have many practical implementations in civil and mechanical engineering. In the other hand, the study of non-ideal vibrations has drawn special attention of engineering researchers in recent years. Let us consider a unbalanced motor on an elastic foundation. If we consider the region before resonance in the Frequency-Response curve of this system, we note that as the power supplied to the motor increases, its speed of rotation increases accordingly. However, this behavior doesn’t continue indefinitely. The closer the motor speed moves toward the resonant frequency, the more power is required to increase the motor speed, as part of the energy is consumed moving the supporting structure. A large change in the power supplied to the motor results in a small change in its frequency and a large increase in the amplitude of the resulting elastic support oscillations. Thus, near resonance, it appears that additional power supplied to the motor only increases the amplitude of the response of the supporting structure while having little effect on the RPM of the motor. Another area of recent interest is Energy Harvesting. In this process, electrical energy is obtained through conversion of mechanical energy from an ambient vibration. In our application, a non-ideal vibration source and a vibration absorber system using piezoelectric material of linear of a nonlinear type is used. The employed methodology to carry out the analysis of this work is as follows. We present the derivation of coupled nonlinear differential equations of the three subsystems. The motor-structure subsystem is defined as a nonideal vibrating system that consists of a nonlinear cantilever beam excited by a small dc motor with eccentric mass, with limited power supply and located in the opposite extremity to the fixed side. The second subsystem is defined as an autoparametric vibration absorber that consists of a flexible beam with tip mass perpendicularly coupled to cantilever beam in its free extremity. The third subsystem consists of piezoelectric devices installed in the base of the absorber beam and an electric circuit is connected to the piezoelectric material in order to produce usable voltage out-put. Next, several numerical simulations were carried out focused on passage through resonance, when the motor rotational frequency is near the cantilever beam natural frequency and when the non-ideal subsystem frequency is approximately twice the absorber beam frequency (two-to-one internal resonance).
Keywords
Autoparametric vibration absorber, Non-ideal system, energy harvesting
