典型钝体主梁断面涡激振动特性研究

发布时间：2018-06-11 21:41

本文选题：桥梁工程 + 风洞试验　；参考：《长安大学》2014年硕士论文

【摘要】：弱阻尼、长、细、轻、柔、是桥梁发展方向的主趋势，桥梁结构（构件）的动力响应问题挑战着桥梁工程界及风工程界，经过几代人的努力，极具毁坏性的颤、驰振等气动弹性问题已得到基本控制，抗风理论设计可保证结构临界风速高于自然桥址处最大设计风速，在主梁、吊杆、桥塔等结构构件较常出现的涡激振动是一种低风速下的风振形式，，虽为限幅振动，但其往复振动形态也能严重影响到桥梁结构（构件）的疲劳，考验着桥梁的强度、稳定性能等，也影响着行人及施工人员的安全及舒适性，这些特点凸显着对涡激振动研究的重要意义。工程人员对实际工程中的涡激振动控制具有很大程度的经验性，往往通过大规模的尝试性试验进行涡激振动的措施制振控制。引起涡激振动的敏感因素很多，极其复杂，使得试验带有很大的盲目性，假使已知断面的某个具体部位控制着涡激振动的发生，再进行针对性的断面改进势必起到事半功倍的效果。本文以某典型钝体断面为研究载体，采集节段梁体模型风洞试验过程中的时程加速度数据及时程压力数据，进而分析采集数据的相关参数（位移值、压力系数脉动值、气动力贡献值、气动力卓越频率值、功率谱密度值、相位谱值等）。从时域、频域两个角度分别讨论涡激振动特性；重点推理阐明了边界层气流漩涡成分周期性脱落激励涡激运动的能量积聚关键区域：基于不同攻角模型梁体的试验响应揭示竖弯涡振特性；依托不同透风形式栏杆模型的试验响应阐述扭转涡激振动特性。
[Abstract]:The weak damping, long, fine, light and flexible is the main trend of the development direction of the bridge. The dynamic response of the bridge structure (component) challenges the bridge engineering and the wind engineering circles. After several generations of efforts, the aeroelastic problems such as extremely destructive tremor and galloping have been basically controlled, and the wind resistance theory is designed to ensure that the critical wind speed of the structure is higher than the natural bridge. The maximum design wind speed is located at the site. The vortex vibration of the structural members, such as the main beam, the hanger and the bridge tower, is a form of wind vibration under the low wind speed. Although it is the amplitude limiting vibration, its reciprocating vibration can also seriously affect the fatigue of the bridge structure (component), test the strength of the bridge, stabilize the performance and so on, and also affect the pedestrian and the construction personnel. Safety and comfort, these features highlight the significance of the study of vortex induced vibration. Engineers have a great degree of Empiricism on the vortex induced vibration control in practical engineering, and often control the vibration of vortex induced vibration by large-scale trial tests. The test has a lot of blindness, if a specific part of the known section controls the occurrence of vortex induced vibration, and then the targeted section improvement is bound to be twice the result of half the effort.
In this paper, a typical blunt body section is used as the research carrier to collect the time history pressure data of the time range acceleration data during the wind tunnel test of the segmental beam body model, and then analyze the relevant parameters of the collected data (displacement, pressure coefficient pulsation value, aerodynamic contribution value, aerodynamic remarkable frequency value, power spectrum density value, phase spectrum value, etc.). The characteristics of vortex induced vibration are discussed in the two angles of the frequency domain. The key reasoning is to clarify the key area of energy accumulation in the periodic exfoliating vortex excitation of the boundary layer. The experimental response of the beam body based on the different angle of attack reveals the characteristics of the vertical bending vortex vibration. Characteristics of vortex induced vibration.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441.3

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