Multi-variate structural reliability assessment for wind energy harvester by Gaidai risk assessment method
Oleg Gaidai, Shicheng He, Jinlu Sheng, Ahmed Alaghbari, Antoine Dembadouno, Tanyaradzwa Kuzvidza, Yan Zhu
Abstract
This case study evaluates structural reliability of hybrid piezoelectric wind GalloPing Energy Harvester (GPEH), utilizing state-of-the-art multi-variate reliability methodology. Conceptualization, design and development of new GPEHs require not only numerical but also experimental studies. Structural durability and reliability investigation require either representative dynamic measurements or extensive Monte Carlo simulations (MCS), given realistic windspeed range. For presented investigation extensive wind tunnel lab tests were utilized to adequately represent GPEH non-stationary dynamics. Vortex shedding occurs when airflow encounters GPEH bluff body, that is supported by an elastic structure. The latter generates non-stationary aerodynamic force causing GPEH vibrations, harvested by piezoelectric (PZT) transducer, converting mechanical vibration energy into electrical. GPEH’s mechanical parameters e.g., cantilever beam rigidity, damping coefficient, effective mass had been evaluated, utilizing free vibration tests. Extensive wind tunnel tests were used to experimentally measure structural hot-spot stresses caused by aerodynamic loading. To analyze GPEH extreme multi-variate vibro-dynamics, state-of-the-art Gaidai multi-modal structural reliability methodology was employed, delivering device’s design failure probability, along with 95% Confidence Intervals (CI). Novelty of the advocated multi-modal structural reliability approach lies within its ability to account for virtually unlimited number of inter-correlated critical parts, or stress hot-spots. Existing structural reliability techniques are mostly based on univariate (1D) or seldomly bivariate (2D) Extreme Value Theory (EVT). Establishing novel multi-modal design approach, enabling structural failure probability prognostics for high-dimensional structural systems was the primary goal of this case study. Note that presented multi-modal reliability methodology is generic, hence it is not limited to GPEH dynamics and can be utilized for a wide range of complex mechanical systems.