Modal electromechanical optimization of cantilevered piezoelectric vibration energy harvesters by geometric variation

作者：Xiong Xingyu; Oyadiji S Olutunde^*

来源：Journal of Intelligent Material Systems and Structures, 2014, 25(10): 1177-1195.

DOI：10.1177/1045389X13502872

• Energy harvesting
• piezoelectric
• electromechanical coupling coefficient
• volumetric power

The design studies of cantilevered piezoelectric vibration energy harvesters have been focused on the optimization of the power output of rectangular cantilevered beam vibration energy harvesters. However, without clarifying the influences of the modal electromechanical coupling and mechanical behaviour clearly, the power outputs cannot be adequately optimized. In this article, a distributed parameter electromechanical model is used to predict the power output with resistive loads, and the parameters are derived using the finite element method. First, a parametric study is presented to investigate the effects of the two factors on the volumetric power of cantilevered vibration energy harvesters. Then, an optimization strategy is implemented to investigate the modal electromechanical coupling coefficient and mass ratio separately using geometric parameter study. Mass ratio represents the influences of modal mechanical behaviour on the power density directly. The findings indicate that the convergent and divergent tapered cantilevered and rectangular cantilevered beam designs with partial coverage of piezoelectric layer are able to generate higher electromechanical coupling coefficient than conventional rectangular cantilevered designs with full coverage. Besides, using convergent tapered cantilevered designs can actually decrease the power density significantly. Both using divergent tapered cantilevered structures and attaching reasonable extra masses with varied locations on vibration energy harvesters can generate larger power density.

• 出版日期2014-7