索桁架柔性光伏支架结构自振特性及地震时程响应分析

Analysis of self-vibration characteristics and seismic time response of flexible photovoltaic bracket structure with cable truss

为探究自振特性参数及地震作用对索桁架柔性光伏支架结构的影响,选取天津市某光伏电站两跨六排索桁架柔性光伏支架采用Ritz向量法进行模态分析,得到不同预应力、光伏面板模拟情况和索桁架间撑杆形式下的结构自振特性;并选取相应地震波对结构进行地震时程分析,得到结构的变形和内力分布情况。结果表明:索桁架柔性光伏支架结构的自振频率低,且刚度较小;结构振型以平动为主,并表现为水平、竖直平动和扭转等耦合的非典型振动;三种结构参数对结构自振频率的影响均较为明显。地震作用下,结构节点Z向位移最大;节点位移最值沿纵排方向的变化较小,但沿横跨方向的变化存在差异;地震下结构的内力最值与静力计算结果相比变化不明显,说明结构内力受地震影响小。

In order to investigate the effects of self-vibration parameters and seismic effects on the structure of the cable truss flexible photovoltaic bracket,a two-span six-row cable truss flexible photovoltaic bracket of a photovoltaic power station in Tianjin was selected for modal analysis by Ritz vector method to obtain the self-vibration characteristics of the structure under different pre-stressing,photovoltaic panel simulation and the form of bracing between cable trusses;and the corresponding seismic wave was selected for seismic time analysis of the structure to obtain the deformation.The results show that the self-oscillation frequency of the cable truss flexible photovoltaic support structure is low and the stiffness is small;the vibration pattern of the structure is mainly in plain motion and shows atypical vibration coupled with horizontal,vertical plain motion and torsion;the influence of the three structural parameters on the self-oscillation frequency of the structure is obvious.Under the seismic effect,the Z-directional displacement of the nodes of the structure is the largest;the variation of the maximum value of the nodal displacement along the longitudinal direction is small,but there is a difference in the variation along the span direction;the maximum value of the internal force of the structure under the earthquake does not change significantly compared with the static calculation results,which indicates that the internal force of the structure is little affected by the earthquake.