岩棉夹芯屋面板对屋盖结构风振效应的影响

Influence of roof panels with rock wool core on wind-induced vibration responses of roof structure

为了探究常用岩棉夹芯复合屋面板的有限刚度和阻尼性能对大跨度结构风振效应的影响机理,基于已有材性试验数据开展该类屋面板的有限元分析.利用模态应变能法进行分析发现,典型檩距屋面板各阶模态均呈现出高阻尼特征并显著降低脉动风幅值.屋面板的有限刚度则会放大风压脉动分量并将能量集中到屋面板的基频附近.屋面板性能对屋盖主体结构风振效应的影响同屋面板与主体结构间的振动协调性、屋面板有限刚度对脉动风压的放大效应以及岩棉夹芯层的阻尼3方面因素密切相关.对于基频较低(2.23Hz)或中等(5.0 Hz)的主体结构,无屋面板风振计算模型会高估风振效应;当基频较高(7.5Hz)时,该影响较小且可以忽略.

Finite element analysis was conducted for the roof panel based on the tested material properties in order to analyze the impact mechanisms on the wind-induced vibration responses of long-span structures considering the finite stiffness and damping of commonly-used composite roof panels with rock wool core.High damping capacities were revealed in the modes of roof panel with typical spans using the modal strain energy method,and the magnitudes of fluctuating wind pressure were significantly depressed.The fluctuating wind components were amplified due to the finite stiffness of roof panel,and the energy was concentrated in the area of the basic frequency of roof panel.The influence of roof panels on the windinduced vibration responses of main structure depends on three major aspects：the vibration synchronism between roof panels and main structure;the enlargement of fluctuating wind pressure due to the finite stiffness of roof panels;the damping of rock wool core.For those roof structures with lower（2.23 Hz）or moderated（5.0 Hz）basic frequency,the wind-induced vibration responses are overestimated if roof panels are not included in the numerical structural model.The influence of roof panels is too small to be neglected for the main structure with higher（7.5 Hz）basic frequency.