Dynamic Characteristics and Flutter Performance of Flexible Cable-Supported Photovoltaic System: Field Measurement and Numerical Simulation

Flexible cable-supported photovoltaic (PV) systems (FCPSs) are characterized by low stiffness and prone to wind-induced vibrations. The rapid increase in the use of FCPSs in engineering applications has resulted in numerous wind-induced damage incidents due to the lack of understanding of their dynamic characteristics and flutter performance. In this study, in-situ measurements were conducted using computer vision techniques to identify the dynamic characteristics of FCPSs with two different spans. A refined finite element (FE) model was then developed and validated using real measurement data. It was used to investigate the effects of key modeling factors, including the multi-layer structure of PV modules, the stiffness contribution of aluminum frames, and the air-added mass, on structural dynamic characteristics. Parameter sensitivity analyses of dynamic characteristics and flutter performance were conducted using the refined model. The results show that the torsional-to-vertical frequency ratios of FCPSs measured at 20[Formula: see text]m and 30[Formula: see text]m span are 1.168 and 1.200, respectively. The damping ratio of the FCPS shows more pronounced nonlinear behavior to amplitude compared to the natural frequency. For multi-row FCPSs with boundary conditions of shared lateral beam, the vertical damping ratio is significantly higher than the torsional one due to the synchronized cable tension variations. The connection between PV modules and cables is crucial to the natural frequency calculated by FE method, while the influence of the aluminum frame and air-added mass may become negligible with thinner PV modules. Tempered glass accounts for almost all of the stiffness in PV modules. Cable spacing is the dominant factor affecting the torsional-to-vertical frequency ratio. The most unfavorable flutter performance is found in the range [Formula: see text] and [Formula: see text]. This study offers additional insights into the wind-vibration performance assessment and the wind-resistance design of FCPSs.