Abstract

The most important duty of a piezoelectric vibration energy harvesting (PVEH) device is to reliably generate electric power as an output for sustainable operation of wireless sensor nodes, without experiencing mechanical failure. However, physical uncertainty, such as inherent variability in material properties and manufacturing tolerances, makes it difficult to guarantee satisfactory performance of the required functions of a PVEH device. Reliability analysis has been widely recognized as of great importance to evaluate system performance, while accounting for physical uncertainty. There have been a few prior attempts to delve into reliability analysis for the design of PVEH devices; these prior efforts were limited to calculating the probability of component success. However, PVEH devices need system reliability analysis that examines multiple performance functions, with the aim of calculating the probability of overall system success. The objective of this study is thus to present a systematic methodology for system reliability analysis of multiple safety events of a PVEH device under physical uncertainty. In this research, after deriving the electroelastically-coupled analytical model, the limit state functions of a PVEH device are derived under multiple safety events including: (1) resistance against fatigue failure; and (2) fulfillment of the target output electrical performances. Finally, system reliability analysis is performed by using the complementary intersection method. This study can provide insightful guidelines for designing a PVEH device under physical uncertainty.