Desenvolvimento e caracterização de um excitador eletrodinâmico com imã permanente

Abstract

The wave phenomenon is the object of study in several areas of engineering. Electrodynamic Exciters coupled to specimens are applied in experiments where forced vibration is required. Accelerating responses can graphically reveal variations in elasticity, phase transformation, and hysteretic response of a shape memory alloy tested under dynamic vibratory loading, for example. Thus, the possibility of using Electrodynamic Exciters and controlling their resonant frequencies by damping when using the spring-damper-mass system is feasible. The present work proposes the design, development and characterization of an Electrodynamic Exciter, capable of producing responses in acceleration, force and displacement amplitudes when electrically excited by a sinusoidal signal. Prototype construction, assembly, signal generation and capture are reported. The Electrodynamic Exciter characterization methodology consisted in analyzing the prototype frequency responses from the installation of four flat springs with different thicknesses by capturing signals by an accelerometer installed on dynamic set top. Comparison of the captured results with the amplified electrical circuit signals are discussed. The excitation frequencies in the range between 1 Hz to 25 kHz were applied in the experiments. The graphs present the responses by the frequency response function, and expose damping in acceleration, force and displacement between 40 Hz and 600 Hz. The total harmonic distortion demonstrated compares the response signals between the accelerometer and amplifier voltages. The permanent magnet force contribution to the resultant force which the equipment produces is discussed. The study contributed to prototype development, and its application has the potential to act in several experiments which require cyclic dynamic loads by forced wave excitation including shape memory alloy.