Vibration energy harvesting and management for wireless sensor networks in bridge structural monitoring

Lifetime of wireless sensor nodes is a big challenge in bridge structural monitoring as these nodes may be deployed inside the bridges. In this situation, it is infeasible to replace batteries or harvest solar and wind energy. To prolong lifetime, vibration energy begins to be utilized to replenish energy for sensor nodes. In this study, a vibration energy harvester based on Micro Fiber Composite is implemented. The structure of this harvester is accommodated to real bridge structures. Detailed theoretical analysis, simulation evaluation and experimental validation are presented. When used in a cable stayed bridge of which the first natural frequency is 1.2785Hz, 0.4mW average power can be obtained. To make the system work, energy prediction and management algorithms are proposed. With these algorithms, 1.1% duty cycle can be achieved which is enough for our bridge structural monitoring applications.