DAMAGE DETECTION AND ENERGY HARVESTING BASED ON VEHICLE AND BRIDGE COUPLED SYSTEM

The study on damage detection is commonly carried out in the frequency domain such as using methods based on modal data, transfer function or frequency response function (FRF), and transmissibility. There is a need for methods that can perform damage detection without attaching sensors to the bridges and without knowing the details of input excitations. In a vehicle-bridge coupled (VBC) system, the vehicle can serve as a force exciter and its dynamic response that can be rather easily measured can also be used to interpret bridge damages. To this end, the transmissibility of a VBC system is first theoretically derived and a numerical study is conducted to investigate the feasibility of detecting bridge damages using the vehicle transmissibility of a VBC system. A parametric study is then conducted to shed light on the sensing vehicle design. In order to make use of the mobility of moving vehicles, two methods were proposed to measure the transmissibility of vehicle responses by using two vehicles. Using these two methods, the modal information such as natural frequencies and modal shape squares was successfully extracted for damage detections. Meanwhile, the feasibility of harvesting energy from the vehicle induced bridge vibration is studied. It is found that by up-converting the low frequency vibrations to higher ones through a multi-impacting device, it is feasible to harvest bridge vibration energy to provide power sources for sensors of bridge monitoring systems.