6 research outputs found
State of the art and development trends of novel nanostructured elastomagnetic composites
No full textThe coupling between elastic and magnetic properties of composite materials made of magnetic particles uniformly dispersed into an elastic matrix was revised. The influence of particles content and size was considered. A unified simple model of the direct and inverse elastomagnetic effect was furnished explaining the experimental results in different experimental conditions. Some applications of elastomagnetic materials in both sensors and actuators are reported and their potentiality is discussed. The correlation between strain and electric conduction in this kind of materials is also presented and the first experimental results on this topic are reported
Mechanical vibration sensor based on elastomagnetic composite
No full textA mechanical vibration sensor based on a novel elastomagnetic composite made of magnetic microparticles uniformly dispersed in an elastic non-magnetic matrix is presented. A theoretical model predicting a linear behaviour of the sensor response with the vibration frequency and amplitude is reported. The obtained experimental results are in agreement with the model predictions for magnetic particle volume content lower than 15%. The ability of this kind of sensor to work at low frequencies, where other devices present a lack of reliability, is a very interesting characteristic of this elastomagnetic sensor. (c) 2006 Published by Elsevier B.V
Novel elastic magnets as actuators core
No full textAn elastic magnet in bar shape, consisting of permanently magnetized Sm2Co7 micro-particles, was produced. The longitudinal strain and/or force amounts given by this novel material under the action of a longitudinal magnetic field are here investigated in order to evaluate the potential applications in very ductile actuator systems
Influence of particle pre-orientation on elastomagnetic effect in a composite material of ellipsoidal Ni microparticles in a silcione matrix
No full textThe dependence of the elastomagnetic effect on the orientation of Ni ellipsoidal microparticles dispersed in a silicone matrix is investigated. When a volume strain is produced on the composite material in a fixed magnetizing field, the effects of mechanical and magnetic torque are simply modeled and the induced magnetization change can be predicted as a function of the particles' pre-orientation. The theoretical predictions are experimentally verified. As a consequence, it is possible to govern the elastomagnetic effect by proper microparticle orientation
A novel elastomagnetic composite for vibration attenuation
No full textA new elastomagnetic composite made of alternate layers of magnetic, rigid material and nonmagnetic, elastic one was conceived, produced and studied with the aim of using for the attenuation of spontaneous vibration. The results of the first laboratory tests, performed applying the developed material on a vibrating structure, show the following peculiar characteristics of the novel elastomagnetic composite multilayer: (i) change of rigidity with the vibration magnitude, (ii) vibration attenuation, (iii) shift of the spontaneous vibration frequency of the structure under control. Based on the above-mentioned characteristics, the new composite represents a promising passive element, with auto-adaptive properties, for vibration attenuation
Dynamic response limits of an elastic magnet
No full textThe potential application of an elastomagnetic composite of micromagnets uniformly dispersed into an elastic matrix for mechanical vibrations detections was investigated. The dynamic response of this material is clearly dependent not only on the elastomagnetic coupling but also on the interaction among the microparticles magnetic moments depending on the external applied field. A theoretical simple model, which gives predictions in agreement with the experimental evidences in the range of the linear behavior, is proposed. © 2004 Elsevier B.V. All rights reserved
