Calculation method for the aerostatic response of flexible cable-supported photovoltaic system considering geometric nonlinearity

This study presents a calculation method for the aerostatic response of a flexible photovoltaic (FPV) system supported by two cables considering geometric nonlinearity in three degrees of freedom. Additionally, a set of equations was derived to determine the nonlinear natural vibration frequency. The equations assume that the variation in cable force depending on vibration amplitude is ignored. The numerical calculation process of the calculation method based on the iterative algorithm was proposed, and the calculation method was verified through aeroelastic tests. Based on this calculation method, the effects of wind speed and structural parameters (span, initial tilt angle, distance between two cables, and initial prestress) on the aerostatic response and the structural stability of the FPV system supported by two cables under the aerostatic effects are further analyzed. The analysis results show that increases in wind speed and span significantly increase the aerostatic response of the FPV system supported by two cables and reduce the structural stability under the aerostatic effects. The initial tilt angle corresponding to the worst structural stability gradually decreases as the wind speed increases. Increasing the distance between the two cables and the initial prestress can significantly reduce the aerostatic response of the FPV system and increase the torsional-bending frequency ratio of the FPV system under the aerostatic effects, thus enhancing the stability of the structure. Increasing the distance between the two cables can reduce the aerostatic torsion angle of the FPV system, while increasing the initial prestress can reduce the aerostatic deflection of the FPV system. These two measures can effectively improve the wind resistance performance of the FPV system, which faces higher design wind speeds, a larger span, and a less favorable initial tilt angle.