Research on wind-induced bending-torsion coupling vibration mechanism and pneumatic vibration reducing measures of large-span flexible photovoltaic arrays under 0° incoming flows

Abstract

Inter-span series connection and inter-row parallel connection are important connection modes to guarantee the overall stability of large-span flexible photovoltaic arrays. However, the array structure is easy to suffer bending-torsion coupling instability vibration under the maximum thrust of 0° incoming flows. In particular, the first row of photovoltaic suffers the most significant wind load and wind-induced vibration. Therefore, it has important engineering application values to study wind-induced bending-torsion coupling vibration mechanism and vibration damping technology of the large-span flexible photovoltaic arrays under the 0° incoming flows. Firstly, a five-row and three-span complete aeroelastic model that can measure displacement of photovoltaic plates was designed and manufactured. Secondly, a 3D noncontact real-time multipoint vibration measurement technology is proposed to study the wind-induced bending-torsion coupling vibration of flexible photovoltaic arrays at varying wind speeds. Later, four new pneumatic spoiler devices were put forward. The pneumatic vibration damping effect was analyzed by the complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and frequency slice wavelet transform(FSWT). Research results demonstrate that: the bending-torsion coupling vibration of the flexible photovoltaic arrays with wind speed under 0° incoming flows changes from the high-order torsion mode and low-order vertical bending mode to low-order bending-torsion coupling mode. When the wind speed is higher 30.36 m/s, the structure begins to produce vertical bending-torsion coupling vibration and frequency-doubled effect, showing significant nonlinear features. Based on static wind displacement response and time-frequency energy distribution of the structure, it found from a comparison that the “>-shaped” spoiler device has the optimal vibration inhibition effect and the maximum vibration inhibition rate is 75.4 %. The “<-shaped” spoiler device has the second vibration inhabitation effect, while the “L-shaped” and “Γ-shaped” devices show the poorest effect and the minimum vibration inhibition rate is 62.3 %.