Development of a rotational energy harvesting tuned vibration absorber for torsional vibration.

In the last decades the demand of wireless sensor and low-power electric devices for condition monitoring in mechanical structures has strongly increased. The advent of large number of sensor nodes and the critical problem of powering them is drawing more and more attention. Batteries are not a valid alternative for consideration given their lifetime, size and efforts required to replace them. In the rotating system such issues are more problematic due to the complication of transferring energy from a stationary source to the rotating parts. Among possible alternative solutions, harvesting the energy from vibration is a suitable method to supply a wireless sensor network, given the amount of power required. However, vibrations represent a problem that needs to be solved. This thesis proposes a novel idea of a combined piezoelectric energy harvesting and torsional vibration absorber for a vibrating rotational system. The idea is to transfer the primary structural vibration from the host structure to the passive auxiliary system. Thus, vibration energy is effectively localized in the secondary, less sensitive component and it can be in part harvested and in part dissipated.