积雪漂移对空间结构动力稳定性的影响

Influence of snow-drifting on dynamic stability of a spatial structure

以一单层柱面网壳为例,以Budiansky-Roth准则为动力失稳判别准则,研究积雪漂移对风雪耦合作用下空间结构动力稳定性的影响。由风洞试验获得结构表面的风荷载时程,通过数值方法模拟风力下积雪在结构表面的漂移。结果表明,风力下网壳顶部的积雪发生侵蚀而迎风与背风面的积雪发生沉积,沉积区和侵蚀区之间形成与风向角一致的分界线。所有风向角下积雪漂移均使单层柱面网壳的动力稳定性降低。风吹雪时间越长,结构的动力稳定性越差,但影响程度随时间逐渐降低。随着初始积雪厚度的增加,结构的动力稳定性降低。

A single-layer cylindrical reticulated shell was taken as an example to study influence of snow-drifing on dynamic stability of a spatial structure under coupled wind and snow loads with Budiansky-Roth criterion.Stochastic wind loads on the structure were obtained from the wind tunnel test,and the snow-drifting on the structure under wind actions was simulated using the numerical method based on FLUENT with an added C＋＋ code.The results showed that snow erodes the top of the shell but deposits on the windward and lee side of the shell,the angle of the dividing line between the erosion area and the deposition area is identical to the corresponding wind direction;the snow-drifting on the shell decreases its dynamic stability in all typical wind directions;the longer the duration of snow-drifting,the worse the dynamic stability of the shell,but the influence of snow-drifting drops with its time duration;also,the dynamic stability of the shell drops with increase in the original snow depth on the shell.