理論解析和實驗量測平板結構附加質量陣列之振動特徵、暫態波傳與反算偵測研究(2/2)

The purpose of this project is to investigate the dynamic behavior of plates with attached mass array by theoretical analysis, numerical simulation and experimental measurement. The influence of additional mass distribution on the vibration characteristic and transient wave propagation of plates will be researched, and applied to design the attached mass array focusing transient waves to optimize electro-mechanical conversion efficiency on piezoelectric energy harvesting system. First of all, the closed-form solution for the resonant frequencies and the mode shapes of plates with different boundary condition and various attached mass array are determined based on thin plate theory and Gorman's superposition method. The finite element simulation and two experimental measurements (impact test and AF-ESPI) are employed to confirm the accuracy of the theoretical solution. The mechanical relationship between attached mass effect on resonance frequency shift and mode shape changes are investigated by the vibration analysis process. Based on normal mode method, the theoretical solutions are constructed to investigate the transient wave propagation in plate medium with attached mass. According to that mass effect changing the wave propagation path, this theoretical analysis model can be utilized to design a mass array for focusing transient wave on a specific area, thereby enhancing the piezoelectric energy capture system energy conversion efficiency. Finally, we present the ability for determining the impact force and detecting impact position from transient behavior reversely.