Advanced Magnetic Materials for Aeronautics

Abstract

In the field of magnetic sensors, magnetic microwires with positive magnetostriction are the materials of the future. Their mechanical and magnetic properties render them ideal materials for applications in aeronautics. A single microwire with a 40 jj.m diameter and a length of 10 mm is capable of capturing information about tensile stresses, magnetic fields, temperature and distance. This information is carried by a parameter called the Switching Field, HSW, which is specific for different types of microwire. Numerous physical qualities affect the HSW and through sensing of HSW, these qualities may be quantified. (A number of physical qualities affecting HSW can be sensed and quantified by means of a contactless induction method.) What distinguishes the system developed by the present authors from other measuring systems based on magnetic microwires is the positioning of a microwire outside the coil system. Thanks to this improvement it is possible to use microwires embedded directly in the construction material. Small dimensions microwires do not damage the structure of the construction material. The absence of a galvanic connection makes this technology even more interesting compared with traditional forge gauges. Offering the possibility of the simultaneous measuring of four parameters, this technology can be used in a wide range of aviation applications. Measurements of an external magnetic field can be usedfor the navigation and stabilization of an aerial vehicle. Tensile stress and distance measuring can be helpful to understand some processes occurring under the surface of the construction material and also to perform fatigue monitoring or structure load monitoring. Another big advantage of magnetic microwires is the low price. Just 1 gram of base material is sufficient to prepare about 40 km of microwire. All these features combine to offer us a material ideal for Smart Sensors, possibly available for use in the near future.

Keywords

• microwires
• strain gauge
• mechanical stress
• contactless