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研究了封闭式双坡屋面风振响应的主贡献模态随屋面坡度变化的规律。将封闭式双坡屋面结构简化为铰支的平面折形梁模型,根据模态贡献方面的研究,得到了双坡屋面的前几十阶模态贡献值,发现主贡献模态一般分布在前两阶模态中,并且屋面坡度的变化对主贡献模态的分布有影响。然后设定计算模型的截面面积、截面惯性矩为随跨度变化的函数,得到表征结构刚度的参数,此时结构的模态形状只与屋面坡度有关而与跨度的具体数值无关,改变屋面坡度可得到不同的主贡献模态分布情况。最后给出不同刚度情况下各坡度范围内结构风振响应需要考虑的主贡献模态阶次。
The main contribution mode of wind-induced vibration response of closed double-slope roof is studied with the variation of roof slope. According to the research of modal contribution, the first decades of modal contributions of double-slope roof are obtained and the main contribution modes are found to be generally distributed in the front In the second-order mode, and the change of roof slope has an influence on the distribution of the main contribution mode. Then, the section area and the moment of inertia of the model are set as a function of the span, and the parameters that characterize the stiffness of the structure are obtained. At this time, the modal shape of the structure is only related to the slope of the roof but not to the specific value of the span. Get the main contribution of different modal distribution. Finally, the main contribution modal order to be taken into account for the wind-induced vibration response of structures with different stiffness is given.