Multi-frequency energy harvesting method for vehicle induced vibration of rail transit continuous rigid bridges

Through dynamic analysis of the train-track-bridge (TTB) system, vehicle induced vibration responses of a rail transit continuous rigid bridge on Guangzhou Metro Line 14 are obtained. Aiming to expand the frequency bandwidth and harvest vehicle-induced vibration energy efficiently from different vibration peaks, 3 types of multi-frequency electromagnetic vibration energy harvesters (EM-VEHs) with 4 submodules are designed in this paper. Based on this, energy harvesting and conversion performance of the proposed multi-frequency EM-VEHs are fully investigated. Energy harvesting analysis show that the harvested vibration energy of each type is up to 90% in the first 50 s during the 5-min train running period. Average power output for 24 h of the 3 types of EM-VEHs are 0.91 W, 1.41 W and 0.84 W in sequence, each of which could meet the normal working requirements of the above sensor unit. Compared with SDOF EM-VEH, all the 3 types of MDOF devices win perfectly in harvesting vibration energy efficiency from different vibration peaks, energy conversion stability with no decrease in power output. Due to the unneglectable mass of the lead blocks in the 4 submodules, the EM-VEHs perform an additional function of being tuned mass damper. Proper matching between the gross mass and vibration energy harvesting efficiency is significant during the design procedure of multi-frequency EM-VEH.