Sobol-based global sensitivity analysis of D-shaped bluff body piezoelectric energy harvesters using SVM surrogate model

To address the unclear parameter regulation mechanism of D-shaped bluff body piezoelectric micro wind energy harvesters caused by strong geometric-system parameter coupling and pronounced nonlinearity, this study develops a synergistic parameter analysis framework combining Support Vector Machine and Sobol global sensitivity analysis to investigate the effects and synergistic mechanisms of wind speed, aspect ratio, mass damping ratio and system stiffness on amplitude ratio.540 sets of full-condition vibration response data were obtained via three-factor three-level orthogonal tests and continuous wind speed scanning. A Support Vector Machine surrogate model with radial basis function kernel was established, achieving a test set coefficient of determination of 0.9655, meeting high-precision analysis requirements. Global sensitivity analysis shows that wind speed dominates amplitude ratio across all conditions with a total effect index of 59.00%, followed by aspect ratio (19.05%), stiffness (10.33%) and mass damping ratio (8.92%). Mass damping ratio exhibits strong interaction effects, while aspect ratio acts almost independently. Dominant parameters evolve significantly with wind speed: mass damping ratio dominates at low speeds, stiffness at medium speeds, and both aspect ratio and stiffness at high speeds. This study reveals the multi-parameter mechanism under coupled vortex-induced vibration and galloping in D-shaped bluff bodies, providing an efficient analytical tool and theoretical support for parameter matching and optimal design of micro wind energy devices.