关键词: 塑料大棚, 荷载, 动力分析, 风振响应, 风振系数

Abstract:

To investigate the dynamic failure mechanism of plastic greenhouses under instantaneous wind loads, the wind-induced response analysis of an 8 m-span plastic greenhouse was conducted, the influence of ridge height and shoulder height on node displacement wind vibration coefficient was discussed. To facilitate engineering applications, recommended values for global displacement wind vibration coefficient were provided. The results showed that the displacement of the plastic greenhouse under wind loads exhibited a “double-peak” curve distribution. The first displacement peak occurred at 1.0 m away from the windward end, and the second displacement peak occurred at 6.3 m away from the windward end. The maximum displacement under instantaneous wind loads was approximately 2.5 times that under mean wind loads. The maximum equivalent stress of the plastic greenhouse occurred at the windward end. The maximum equivalent stress under instantaneous wind loads was about 2.1 times that under mean wind loads. The ridge height of the plastic greenhouse had little influence on the nodal displacement wind vibration coefficients. With the shoulder height unchanged and the ridge height increasing from 3.4 m to 3.8 m, the nodal displacement wind vibration coefficient varied about 5%. When the ridge height was constant, the nodal displacement wind vibration coefficient decreased with the increase of shoulder height. For plastic greenhouses with a span of 8 m, shoulder height range of 1.8 m to 2.0 m, and ridge height range of 3.4 m to 3.8 m, the global displacement wind vibration coefficient varied from 2.23 to 2.43. The results could provide a theoretical basis for the wind-resistant design of plastic greenhouse structures.

Key words: plastic greenhouse, load, dynamic analysis, wind induced response, wind vibration coefficient