悬挑式张弦罩棚结构的风致疲劳分析

悬挑式张弦梁结构是由传统张弦梁结构改进的高效空间结构，其单榀张弦梁结构由上拉索、弦杆以及下抗风索组合而成。由于此类结构的风致振动效应显著，有必要研究其风致疲劳效应的影响。为研究悬挑式张弦罩棚结构的风致疲劳损伤，以某体育场罩棚为研究对象，采用几何缩尺比为1∶150的ABS塑料刚性模型进行B类风场下的风洞试验，得到各测点的风压时程数据，转化为有限元模型的节点风荷载进行风致振动响应分析并得到拉索的应力时程。利用雨流计数法对拉索的应力时程进行统计计数，并结合EuroCode2中所推荐的拉索S-N曲线，采用Miner准则对拉索的疲劳损伤进行线性累积，从而对该悬挑式张弦梁结构中的拉索进行疲劳损伤评估。结果表明：拉索构件的风致疲劳损伤随风向角变化明显，最不利风向角在180°附近；由于拉索构件的几何非线性特性，其疲劳损伤随风速变化呈非线性增长趋势。

Wind-induced fatigue analysis of a cantilevered string canopy structure

Cantilever string structure is a high-efficiency space structure improved from traditional beam-string structure, where the single joist chord structure is composed of upper prestressed cable, chord, and lower prestressed cable. Due to the significant wind-induced effect of such type of structure, it is necessary to investigate its wind-induced fatigue effects. In this paper, a case study of a canopy structure of a stadium was presented to evaluate wind-induced fatigue damage. In order to obtain the time history of wind pressure at each measuring point, a rigid model made of ABS plastic with a geometric scale ratio of 1:150 was adopted to conduct the wind tunnel test in the B-type wind field. Time histories of steel cable stresses were obtained from the finite element simulation, where the node wind loads were transformed from the wind pressure measurement results obtained by the wind tunnel test. The time histories of cable stress obtained from the wind vibration analysis were counted as series of stress ranges by the rainflow counting algorithm. The Miner rule was used to estimate the linear accumulation of fatigue damage based on the S-N relationship of steel cable recommended by Eurocode 2. The results show that the wind-induced fatigue damage of cables varies significantly with the wind direction angle, and the maximum values are generally obtained around wind direction angle of 180°. The fatigue damage increases nonlinearly with the wind speed due to the geometrical nonlinearity of the cable members.