高墩大跨桥梁抖振时域分析及抖振疲劳研究

发布时间：2018-04-04 05:03

本文选题：高墩大跨连续刚构桥　切入点：抖振　出处：《长安大学》2016年硕士论文

【摘要】：随着人们生活质量的不断提高,便捷的交通也成为人们日益关注的焦点。连续刚构桥是一种较为常见的桥型,交通的发展使得连续刚构桥梁也越来越趋于高墩大跨方向发展,整体刚度已不如从前,那么风荷载引起的结构问题便日益突出并成为桥梁工程界亟待解决的重点问题。自然风中的脉动紊流分量会引起桥梁结构物的风致抖振,这种振动是在任意风速下都会产生的限幅振动。这种风致振动虽不会像颤振一样引起毁灭性的破坏,但是会导致结构的大变形,影响行车安全和驾驶人的舒适性。由抖振力引起频繁的应力循环会产生结构疲劳,缩短桥梁使用寿命。因此,本文以高墩大跨度连续刚构桥实桥为研究对象,利用ANSYS的APDL语言二次开发功能以及MATLAB程序语言进行施工及成桥阶段风致抖振响应研究,应用Miner线性累积损伤准则进行了抖振力荷载作用下桥梁结构危险部位疲劳损伤的研究。主要内容包括:1)基于谐波合成法对骑骡沟大桥所处地理位置的脉动风风场进行模拟,对模拟风速的功率谱与目标谱进行对比。2)基于大型有限元软件建立骑骡沟大桥施工阶段及成桥阶段有限元模型,计算该桥动力特性。并对骑骡沟大桥施工阶段及成桥阶段静力风荷载作用下的风致响应进行计算分析。3)运用Matrix27单元使得自激力通过矩阵形式在有限元模型中实现参数化模拟。4)运用ANSYS瞬态动力分析将脉动风转化为时域化的抖振力荷载。对仅考虑Davenport准定常抖振力荷载的桥梁进行时域分析,其次添加模型气动自激力并计算考虑自激力的抖振响应,与未考虑自激力的工况做对比。5)计算北山大桥主梁关键点应力谱,运用雨流计数法对应力时程进行统计分析并得出应力循环及应力幅。根据关键点在采样时距中的应力循环和应力幅运用Miner线性累积损伤准则计算采样时距的疲劳累积损伤并根据疲劳累积损伤计算抖振力荷载作用下该桥危险点的疲劳寿命。
[Abstract]:With the improvement of life quality, convenient transportation has increasingly become the focus of attention. The continuous rigid frame bridge is a common traffic bridge, with the development of the continuous rigid frame bridge is more and more high pier and large span direction, the overall stiffness is less than the former, so structural problems caused by wind load will become increasingly prominent bridge engineering and become the key problem needs to be solved. The wind-induced buffeting of pulsating turbulent components of natural wind will cause the bridge structure, the vibration is limiting vibration at any speed will produce. This is not like the wind-induced vibration flutter caused devastating damage, but will lead to large deformation of the structure and the impact on traffic safety and driving comfort. Frequent stress cycle will produce fatigue caused by buffeting force, shorten the service life of the bridge. Therefore, the high pier large span. Continuous rigid frame bridge bridge as the research object, the construction and study of wind-induced buffeting response of bridge using APDL language two development function of ANSYS and MATLAB programming language, studied the fatigue damage of bridge structure risk effect of buffeting force load using Miner linear cumulative damage criteria. The main contents include: 1) simulation fluctuating wind field harmonic synthesis location of riding a mule ditch bridge based on power spectrum and the target spectrum to simulate the wind speed compared to.2) the establishment of riding a mule ditch bridge construction stage based on finite element software and bridge finite element model, calculating the dynamic characteristics of the bridge. And the wind on a mule construction stage ditch bridge and the bridge phase static wind load response were calculated and analyzed by Matrix27.3) unit makes the self-excited force through the matrix form in a finite element model to realize parametric modeling. 4) using ANSYS transient dynamic analysis will be transformed into fluctuating wind buffeting loads. The time domain of the time domain analysis considering only Davenport quasi steady bridge buffeting force load, and then add the buffeting model self-excited aerodynamic forces were calculated considering self-excited force response, do not consider the comparison between the.5 and the self-excited force condition) Beishan bridge calculation key point stress spectrum, the rain flow counting method of stress time history analysis and the cyclic stress and stress amplitude. According to the key points of cyclic stress and stress amplitude by Miner linear cumulative damage criterion calculation of the sampling interval the cumulative fatigue damage and fatigue life according to the damage calculation of buffeting vibration loads of the bridge fatigue cumulative danger point in sampling distance.

【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U441

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