FEM simulation of the Nitinol wire

In recent years, one of the most promising new actuator technologies is based on the use of Shape Memory Alloys (SMA). The main challenge for the application of devices that use these materials is the hysteresis in the phase transition they suffer during actuation. Finite element analysis (FEA) is an important aid in the simulation of mechanical properties and thermal fields in actuators. Dynamic simulations give in many cases enough information without the necessity of building a prototype. We have used ABAQUS to simulate a Nitinol wire used in a micropositioning actuator. The model parameters, not given by the supplier but required by the FEA program, have been obtained by thermal and mechanical characterization of the material used. The output force is computed and compared with the measurements

High performance magnetoimpedance in FeNi/Ti nanostructured multilayers with opened magnetic flux

Magnetic [FeNi (170 nm)/Ti (6 nm)] 3/Cu (L Cu =250 or 500 nm)/[Ti (6 nm)/FeNi (170 nm)] 3 multilayers were designed with focus on high frequency applications. They were deposited onto glass or a microfluidic system compatible flexible Ciclo Olefin Copolymer substrate and comparatively tested. A maximum sensitivity for the total impedance of 110%/Oe was obtained for a driving current frequency of 30 MHz for [FeNi/Ti] 3/Cu (L Cu = 500 nm)/[Ti/FeNi] 3 multilayers deposited onto a glass substrate and 45%/Oe for a driving current frequency of 65 MHz for the same multilayers deposited onto the flexible polymer substrate, a very promising result for applications. The possibility of using flexible substrate/[FeNi/Ti] 3/Cu/[Ti/FeNi] 3 multilayers as MI pressure-sensitive elements was also demonstrated. Copyright © 2012 American Scientific Publishers All rights reserved