基于模型测压试验的扁平箱梁涡振机理研究

发布时间：2018-03-03 14:39

本文选题：涡激振动　切入点：机理　出处：《石家庄铁道大学》2015年硕士论文　论文类型：学位论文

【摘要】：涡激振动是大跨度桥梁主梁在低风速下极易发生的一种风致振动现象。国内外已有多座大桥发生了涡激振动,严重影响了桥梁的使用功能和行车的安全。虽然目前已经能够找到一些抑制涡激振动的气动措施,但对于特定的桥梁主梁,气动措施的选择仍存在一定的盲目性。造成这种现象的根本原因是桥梁主梁涡激振动发生的内在机理尚不是十分明确。本文针对在大跨度桥梁中经常采用的扁平箱形断面梁,开展了模型在刚性悬挂静止状态和弹性悬挂涡振状态下的测压风洞试验。从箱梁横断面气动力特性和箱梁气动力展向相关特性两个角度研究了涡激振动发生的内在机理。(1)基于箱梁横断面气动特性的涡振机理研究。通过对比分析静止与涡激振动两种状态下模型表面测点的平均风压系数、脉动风压系数、测点的功率谱及测点气动力与总气动力的相关性,揭示了竖弯涡振发生的内在机理。研究发现:竖弯涡振发生的原因是气流在扁平箱梁上表面上游周期性的分离造成上表面区域脉动压力的显著增强,测点气动力与总气动力有良好的相关性,各测点压力功率谱具有相同的卓越频率。(2)基于箱梁气动力展向相关特性的涡振机理研究。通过对比分析静止与涡激振动两种状态下模型总气动力及各测点气动力的展向相关性,揭示了竖弯涡振发生的内在机理。研究发现:竖弯涡振发生的原因是扁平箱梁总气动力和各测点(尤其是上表面上游、上表面下游、背风腹板、迎风腹板前端四个区域的测点)气动力的展向相关性显著增强。
[Abstract]:Vortex induced vibration is a phenomenon of wind-induced vibration of long-span bridge girder can easily occur at low wind speeds. The vortex induced vibration at home and abroad, many bridges, seriously affect the use function of the bridge and traffic safety. Although there have been able to find some suppression of vortex induced vibration of aerodynamic measures, but for specific the bridge girder, the aerodynamic measures, there are still some blindness. The root cause of this phenomenon is the inherent mechanism of bridge girder of VIV is not very clear. In view of the flat box deck is often used in the large span bridge girder, carry out the model in the wind tunnel test of the rigid suspension state of vortex vibration under the static state and the elastic suspension from the box girder cross-section. The aerodynamic characteristics and aerodynamic force of box girder in the two angle characteristics of the intrinsic mechanism of the vortex induced vibration occurred (1) based on the box. The vibration mechanism of beam cross section of aerodynamic characteristics. Through the comparative analysis of the average wind pressure coefficient measurement model of surface static and vortex induced vibration under two conditions, the fluctuating wind pressure coefficient, correlation and spectrum measurement points and total aerodynamicforce point of power, the internal mechanism of the vertical vortex vibration reveals the students study found that: the reason of vertical vortex induced vibration is the flow separation caused by periodic upstream surface enhanced on the surface area of the fluctuating pressure in the flat box girder, measuring points and total aerodynamicforce have good correlation, each point has excellent pressure power spectrum of the same frequency. (2) the vortex induced vibration study on the mechanism of related to the characteristics of the box girder. Based on the analysis of the static aerodynamic show and vortex induced vibration under two model of aerodynamic force and aerodynamic force of each measuring point the spanwise correlation by comparing the inner mechanism of the vertical vortex induced vibration occurred in the study found was revealed: The cause of vertical vortex vibration is that the total aerodynamic force of flat box girder and the measuring points of all points, especially the upper surface, upstream, downstream, leeward, and the front area of the four sides of the windward webs, are significantly increased.

【学位授予单位】：石家庄铁道大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441.3

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