向家坝泄洪诱发低频声波引起房屋卷帘门振动研究

发布时间：2018-11-11 01:05

【摘要】：高坝泄洪诱发结构振动、空蚀破坏、下游冲刷和雾化等工程灾害已被人们熟知和广泛研究,而高坝泄洪诱发的低频声波(10Hz以下气压脉动)及其对环境的危害在国内基本没人研究。鉴于向家坝、锦屏等工程原型和模型泄洪时都实测到低频声波,实际工程中会在一定范围内存在诱发房屋门窗振动、造成人体不适等环境危害。通过现场观测和模型分析,研究向家坝泄洪诱发低频声波对附近居民楼卷帘门的振动影响,并提出合理的解决方案,减小低频声波带来的危害。首先,在向家坝下游水富县城选取并布设典型测点,对各测点处低频声波进行实时监测,并对测试结果进行分析处理,得到各测点低频声波的脉动压力时程图和功率谱密度图,绘制低频声波均方根值在空间的分布情况,分析低频声波均方根值和主频随流量改变的变化规律,并给出低频声波的安全阈值,依此评定低频声波的主要影响范围。其次,利用仿真软件ANSYS建立卷帘门有限元模型,对其进行有限元分析:(1)对卷帘门进行模态分析,计算各阶固有频率和振型,分析卷帘门共振的可能性;(2)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;(3)对卷帘门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;(4)模拟卷帘门在不同开度时的振动响应,对比分析不同开度工况卷帘门的激振特性;(5)模拟卷帘门在不同刚度边界时的振动响应,对比分析不同刚度边界对卷帘门激振特性的影响。再次,在育才路5栋卷帘门卷轴处施加实测顺河向位移荷载,模拟房屋结构振动引起的卷帘门振动,并和卷帘门在低频声波作用下的振动情况进行对比,分析二者对卷帘门摆动现象影响的大小。结果表明,低频声波是引起卷帘门晃动的主要因素。最后,以平板为例,分别模拟不同尺寸、不同材质对平板自振特性和响应特性的影响,类推到卷帘门,得出卷帘门的优选方案,并给出了几种有效的减振降噪措施,对低频声波引起卷帘门振动起到一定的改善作用。
[Abstract]:Engineering disasters such as structural vibration cavitation erosion downstream erosion and atomization caused by flood discharge of high dams have been well known and widely studied. However, the low frequency acoustic wave induced by flood discharge of high dam (below 10Hz pressure pulsation) and its harm to environment have not been studied in China. In view of the fact that low-frequency sound waves are measured in the flood discharge of Xiangjiaba, Jinping and other engineering prototypes and models, the vibration of doors and windows of houses will be induced in a certain range in actual projects, which will cause environmental hazards such as malaise to human body and so on. Based on field observation and model analysis, the effect of low-frequency acoustic wave induced by flood discharge on the vibration of the rolling door of residential building in Xiangjiaba is studied, and a reasonable solution is put forward to reduce the harm caused by low-frequency acoustic wave. First of all, the typical measuring points are selected and set up in Shuifu County, downstream of Xiangjiaba. The low frequency acoustic waves at each measuring point are monitored in real time, and the test results are analyzed and processed, and the pulsating pressure chronogram and power spectral density diagram of the low frequency sound waves at each measuring point are obtained. The distribution of the root mean square (RMS) of low frequency sound waves in space is plotted, and the variation law of the root mean square value and main frequency of low frequency sound waves with flow is analyzed, and the safety threshold of low frequency sound waves is given, according to which the main influence range of low frequency sound waves is evaluated. Secondly, the finite element model of the shutter door is established by using the simulation software ANSYS, and the finite element analysis is carried out. (1) the modal analysis of the shutter door is carried out, and the natural frequencies and modes of each order are calculated, and the possibility of resonance of the shutter door is analyzed. (2) the modal analysis of the shutter door under different opening and boundary conditions is carried out, and the influence of opening and boundary constraints on the natural vibration characteristics of the shutter door is simulated. (3) the transient analysis of the rolling door under different constraint conditions is carried out to simulate the vibration response of the shutter door, and the boundary condition is improved according to the simulation results, so as to reduce the sloshing of the shutter door and improve the dynamic characteristics of the system. (4) simulating the vibration response of the shutter with different opening, and comparing and analyzing the exciting characteristics of the shutter under different opening conditions; (5) simulating the vibration response of the shutter door with different stiffness boundary, and comparing and analyzing the influence of the different stiffness boundary on the exciting characteristic of the shutter door. Thirdly, at the reel of five rolling shutters in Yucai Road, the measured displacement load along the river is applied to simulate the vibration of the rolling door caused by the structural vibration of the building, and the vibration of the shutter door under the action of low frequency acoustic wave is compared with that of the shutter door under the action of low frequency acoustic wave. The influence of the two factors on the swing of the shutter door is analyzed. The results show that the low frequency acoustic wave is the main factor causing the rolling door sloshing. Finally, taking the flat plate as an example, the effects of different sizes and materials on the natural vibration characteristics and response characteristics of the flat plate are simulated, and the optimum selection scheme of the rolling shutter door is obtained by analogy to the rolling door, and several effective measures for reducing vibration and noise are given. It can improve the vibration of rolling door caused by low frequency sound wave.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV135.2;TU311.3

【相似文献】