闭口钢箱梁经验非线性涡激气动模型参数识别关键问题研究

发布时间：2018-11-03 07:11

【摘要】：大跨度桥梁柔性大、自振频率低,风致振动是其设计的控制因素。对于大跨度闭口钢箱梁桥,低速绕过的气流常在其两侧形成旋涡,旋涡的不均匀脱落形成涡激振动,影响行车安全和舒适性。本文以闭口钢钢箱梁桥为研究对象,基于节段模型测力、测振同步涡激振动风洞试验,对Scanlan经验非线性模型气动参数识别关键问题进行了研究。首先,进行节段模型测力、测振同步涡激振动风洞试验,提取涡激振动和天平力时程信号。基于递归图及其定量分析理论,对测力、测振数据进行递归分析,研究了涡激气动力和涡振位移最优尺度的选择方法。其次,基于Scanlan经验非线性涡激气动模型,使用最小二乘法对分离所得涡激力进行模型参数识别。研究了测力、测振非同步对Scanlan经验非线性涡激气动模型参数识别的影响,发现微小的时间延迟对参数识别和反算结果造成较大的影响,证明Scanlan经验非线性涡激气动模型对于测力、测振同步性非常敏感,保持实验模型涡激力与位移数据同步采集,对该类试验非常重要。最后,基于Scanlan经验非线性涡激气动模型参数识别结果,实现了二维涡激振动响应数值模拟方法。完整模拟了桥梁从涡振起振到涡振消失的全过程,并将数值模拟结果与试验结果进行了对比,两者均呈现“几”字型,验证了本文涡激振动数值模拟方法的正确性。
[Abstract]:Long span bridge is flexible, low natural vibration frequency and wind-induced vibration is the control factor of its design. For long span closed steel box girder bridge, vortex is often formed by low speed flow around the bridge, and vortex-induced vibration is formed by uneven shedding of vortex, which affects driving safety and comfort. In this paper, the key problem of aerodynamic parameter identification of Scanlan empirical nonlinear model is studied based on the wind tunnel test of synchronous vortex-induced vibration measured by segmental model. Firstly, the wind tunnel test of synchronous vortex-induced vibration was carried out by using segmental model to extract the vortex-induced vibration and balance force time-history signals. Based on the theory of recursive graph and quantitative analysis, the method of selecting the optimal scale of vortex-induced air force and vortex-induced displacement is studied by recursively analyzing the data of force and vibration measurement. Secondly, based on the Scanlan empirical nonlinear vortex-induced aerodynamic model, the model parameters of the separated vortex-induced forces are identified by the least square method. The influence of force measurement and vibration measurement on the parameter identification of Scanlan empirical nonlinear vortex-induced aerodynamic model is studied. It is found that the small time delay has a great influence on the parameter identification and back-calculation results. It is proved that the empirical nonlinear vortex-induced aerodynamic model of Scanlan is very sensitive to force measurement and vibration measurement synchronism. It is very important for this kind of test to keep the data of vortex-induced force and displacement simultaneously collected from the experimental model. Finally, based on the Scanlan empirical nonlinear vortex-induced aerodynamic model parameter identification results, a two-dimensional vortex-induced vibration response numerical simulation method is realized. The whole process of bridge vibration from vortex vibration to vortex vibration disappearance is simulated, and the numerical simulation results are compared with the experimental results. The numerical simulation results show "several" shape, which verifies the correctness of the numerical simulation method of vortex-induced vibration in this paper.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U441.3

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