Structural health monitoring is an emerging approach for non-destructive inspection in which the distribution of stresses and strains in a load-bearing structure is monitored in real-time by embedded or attached sensors. In this research, we develop a novel smart composite by incorporating magnetostrictive Terfenol-D fillers into different polymeric matrices, and design a method for health and strain monitoring in the smart materials.
Magnetostrictive fillers induce a change in their surrounding magnetic field when subjected to strain. These magnetic fields are readily measured with a standard Gaussmeter, thus, the filler may serve as natural strain sensors requiring neither power nor wiring in order to create and emit its signal.
We demonstrate the applicability of this technology in two distinct matrices, a rigid epoxy resin for adhesive bonding, and a viscoelastic polybutadiene resin for solid fuel compounds. We present methods of fabrication of the smart composite specimens, as well as experiments designed to load the smart composite specimens to characteristic loads in real life conditions, while measuring the induced changes in the magnetic field. We report the sensitivity of the strain measurement based on the magnetic field readings.
The high resolution of measurement, on the order of tens of micro strains, leads us to believe this method has true potential for commercial applications.
Further work has begun on exploring the repeatability of the sensing technique and its behavior in quasi static and dynamic loading scenarios.
