两索支承柔性光伏支架固有频率实用估算公式及其演化规律OA

The natural frequency of a structure is a key factor affecting the wind-induced response.Establish-ing the practical estimation formulas for the natural frequency of flexible photovoltaic supports is of great sig-nificance for their wind-resistant design.Based on Hamilton principle,the analytical expressions for the bend-ing and torsional modal frequencies of the two-cable-supported flexible photovoltaic supports were derived.The precision and applicability of the proposed formulas were substantiated by a finite element model cali-brated with field measurements,and the evolution law of the natural frequencies was revealed.The results show that the ratio of the cable spacing d to the module length B governs the torsional-to-bending frequency ra-tio,which can be approximated by the simplified expression√3 d/B.The frequency of the structure decreases first and then increases with the increase of the cable tension,and it decreases with the increase of the photovol-taic module tilt angle.The torsional frequency increases with the increase of the cable spacing.The influence of the stiffness of the photovoltaic modules on the torsional frequency can be ignored.The sag effect can in-crease the frequencies for symmetric modes,but has no effect on asymmetric modes.