Design optimization under uncertainty for reliable power generation performance of piezoelectric energy harvester.

摘要

Vibration energy harvesting was initially studied using the principle of linear vibration, which limits power generation to single frequency inputs. However, the random nature of vibration in the real world belies the practicality of single frequency inputs. For this reason, linear energy harvesters (EHs) are not practical. In order to overcome the weakness of linear EHs, multiple configurations of nonlinear vibration EHs have been studied and developed to account for the arbitrary nature of vibration and to broaden power bands. Although there has been successful development of nonlinear EH configurations that address the shortcoming of linear EHs, most nonlinear EHs are not practical since the designs tend to be bulky and complex. In addition, there has been no in depth study on improving the reliability of an EH, and the power output of a vibration EH is known to be sensitive to various uncertainties such as material properties, geometric tolerances, and loading conditions.;This thesis presents an innovative nonlinear EH design and its reliability-based design optimization (RBDO) methods that demonstrates consistent power generation performance under various uncertainties. The new concept design is a purely mechanical nonlinear vibration EH that utilizes curved shell implemented in the center of the beam to induce nonlinearity. The proposed design for a nonlinear EH is simple and compact. RBDO for the proposed nonlinear EH configuration is performed. As a result, a compact nonlinear harvester is developed with reliable power generation performance under manufacturing uncertainties.