Dynamical Analysis Applied to Passive Control of Vibrations in a Structural Model Incorporating SMA-SE Coil Springs

Yuri J O Moraes,Antonio A Silva,Antonio G B De Lima,Paulo C S Da Silva,Marcelo C Rodrigues,Rômulo P B Dos Reis

doi:10.1155/2018/2025839

Abstract

Mechanical vibrations are severe phenomena of the physical world. These oscillations may become undesirable and may cause temporary and even irreversible damage to the system. There are several techniques to minimizing these vibration effects ranging from passive methods to the use of controllers with smart materials. In this sense, this study aims to analyze a passive vibration control system installed in a structure that simulates two-floor buildings. This system based on the incorporation of one SMA-SE (Superelastic Shape Memory Alloys) coil springs configuration for energy dissipation and the addition of damping. Modal analysis was performed using analytical, numerical, and experimental methods. In an experimental basis, response amplitudes were analyzed for free and forced vibrations in different configurations. As compared with the structure configuration with steel spring, the forced vibrations FRF (Frequency Response Function) analysis showed a reduction in displacement transmissibility of up to 51% for the first modal shape and 73% for the second mode in the SMA-SE coil spring configuration. As for damping, there was a considerable increase in the order of 59% in the first mode and 119% in the second, for the SMA-SE springs configuration.

Highlights

A periodic oscillation or mechanical vibration is a phenomenon defined as any movement that comes repeated after some time. us, the theory of vibration studies the oscillatory movements of the bodies and the forces associated with them
A vibratory system alternates the transfer of its potential energy to kinetic energy. is system generally contains a means for storing potential energy, for example, a spring, another for storing kinetic energy, as a mass, and one for gradually dissipating energy, called as damper [1, 2]
Note that a spring element made of steel stores elastic potential energy and returns a portion to the system in the form of kinetic energy. e di erence between the stored energy and the energy recovered is due to the structural damping of the spring itself

Summary

Introduction

A periodic oscillation or mechanical vibration is a phenomenon defined as any movement that comes repeated after some time. us, the theory of vibration studies the oscillatory movements of the bodies and the forces associated with them. A periodic oscillation or mechanical vibration is a phenomenon defined as any movement that comes repeated after some time. Is system generally contains a means for storing potential energy, for example, a spring, another for storing kinetic energy, as a mass, and one for gradually dissipating energy, called as damper [1, 2]. Under the viewpoints of mechanics, can be verified these effects in our everyday life, whether in the use of domestic appliances or the mining industry, among other forms [3]. Some physical phenomenon may become undesirable and may cause temporary or irreversible damage in a specific system, due to the malfunction, the progressive increase of noise, shortened life of its components, increased maintenance costs, and in the more severe cases with the own collapse or structural failure. It is of equal importance to consider the effects provoked by natural phenomena, like winds, and waves of the sea [4,5,6]

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