Bi-axial Vibration Energy Harvesting

This report describes a vibration energy harvesting approach that uses a magnetoelectric (ME) transducer to harvest energy from bi-axial vibrations. The approach is being explored as a potential means of powering in situ structural health monitoring systems embedded within aircraft and other high value engineering assets that experience mechanical vibration. A bi-axial oscillator is created using a permanent-magnet/ball-bearing arrangement, which has the added benefit of permitting a relatively compact design. The magnet produces a bi-axial restoring force on the bearing, and as the bearing oscillates it steers magnetic field through a magnetostrictive/piezoelectric laminate transducer thereby producing an oscillating charge that can be harvested. A simple laboratory demonstrator of a bi-axial ME harvester was created using a Terfenol-D/lead zirconate titanate/Terfenol-D transducer, and was shown to produce a peak rms power of 121 W from an rms acceleration of 61 mG at 9.8 Hz.