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伴随大坝泄洪产生的低频声波(10 Hz以下气压脉动),在一定范围内会诱发房屋门窗振动、造成人体不适等。为了评估泄洪低频声波产生的环境危害,在开展泄洪低频声波原型观测的基础上,利用有限元软件建立房屋卷帘门结构系统模型。首先对卷帘门进行模态分析,计算各阶固有频率和振型;接着分别对卷帘门在不同开度及不同边界条件下进行模态分析,模拟开度和边界约束对卷帘门自振特性的影响;然后对系统进行不同约束条件下的瞬态分析,模拟卷帘门的振动响应,并根据模拟结果改进边界条件,从而减小卷帘门的晃动,改善系统的动态特性。最后模拟了房屋结构振动引起的卷帘门振动响应,其振动量级远小于低频声波直接作用造成的振动。
Low-frequency sound wave (pressure pulsation below 10 Hz) accompanied by flood discharge from the dam will cause vibration of doors and windows in a certain range and cause human discomfort. In order to evaluate the environmental damage caused by flood and low frequency sound waves, a structural model of the rolling shutter doors was established by using the finite element software based on the prototype observation of low frequency sonic waves of flood discharge. Firstly, the modal analysis of the roller shutter door was carried out to calculate the natural frequencies and modes of each step. Then the modal analysis of the roller shutter door under different opening and different boundary conditions was carried out respectively to simulate the influence of the opening and boundary constraints on the self-vibration characteristics of the roller shutter door. The system transient analysis under different constraints to simulate the shutter door vibration response, and based on the simulation results to improve the boundary conditions, thereby reducing rolling shutter doors to improve the dynamic characteristics of the system. Finally, the vibration response of the rolling shutter door caused by the vibration of the building structure is simulated, and the vibration magnitude is much smaller than the vibration caused by the direct action of the low frequency sound wave.