Modal Identification and Finite Element Model Updating of Flexible Photovoltaic Support Structures Using Multi-Sensor Data

Flexible photovoltaic (PV) support structures are widely used due to their large span, high land-use efficiency, low construction cost, and short construction periods. However, they exhibit low stiffness, light weight, and low damping, making them wind-sensitive and prone to wind-induced vibrations. Evaluating their dynamic performance remains challenging due to two critical limitations: the lack of field-measured modal properties and the absence of reliably validated finite element (FE) models. In this study, field modal testing of a flexible PV support structure was conducted, and high-order modal properties were identified from multi-sensor data. Subsequently, a response surface model was constructed, and the optimal combination of metal frame mass, cable initial tension, and column modeling was obtained through particle swarm optimization (PSO), leading to an updated FE model. The results show that the damping ratios of the first and second torsional modes is only 0.7% and 0.4%, respectively, highlighting the need to consider low damping properties. Besides, the deviation between the design and actual values of structural parameters cannot be ignored.