Investigation of wind-induced vibration evolution mechanisms in long-span flexible photovoltaic structures using three-dimensional digital image correlation method in aeroelastic wind tunnel tests

Existing measurement technologies and methods have limited previous aeroelastic wind tunnel tests on long-span flexible photovoltaic (PV) to localized measurement points, lacking refined, multi-region, and multi-point analysis. To further investigate the most adverse wind-induced vibration evolution mechanisms in long-span flexible PV across multiple regions, this study utilizes a three-dimensional digital image correlation method with a visual displacement analyzer to obtain more precise and efficient structural displacement responses. By examining aerodynamic vibration characteristics at smaller scales, the study reveals the most adverse vibration evolution mechanisms for the flexible PV. And by synchronizing structural mode evolution with the correlation of vibration frequencies and displacement responses at various measurement points, the study identifies the most adverse aerodynamic vibration mechanisms. Finally, targeted recommendations for vibration suppression in long-span flexible PV are proposed. The findings show that, compared to 0° wind direction, the flexible PV is more prone to larger displacement and high-frequency vibrations at 180° wind direction, with the most adverse vibration response observed at the edge span. At 0° wind direction, vibration characteristics are primarily linear or at a critical state between linear and nonlinear responses, while at 180° wind direction, modes include linear response, a critical state, and nonlinear response. The “high horizontal response participation—high-frequency vibration” mechanism indicates that the transition from linear to nonlinear responses arises from a significant increase in horizontal displacement participation, along with high-frequency vibrations in both vertical and horizontal directions.