基于动应变的梁式桥梁动挠度识别

发布时间：2018-01-08 09:38

本文关键词：基于动应变的梁式桥梁动挠度识别　出处：《合肥工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：在桥梁健康监测中桥梁挠度作为结构变形的一种描述形式,可以评价桥梁质量及运营状态,反映桥梁的刚度,特别是桥梁的动挠度,更是桥梁受力变形最为实时的体现,因此对桥梁的动挠度进行监测具有重要意义。近年来在桥梁挠度测量方法中,基于应变的方法受到了广泛关注和研究。目前基于应变测试识别桥梁挠度的方法主要有基于平均曲率方法,基于最小二乘曲线拟合方法和基于共轭梁法。这些方法在识别桥梁静挠度方面已经取得了一定的应用,但是对于桥梁动挠度识别来说,由于静挠度的识别原理仅考虑静力的应变-位移关系,并没有考虑桥梁振动的影响,因而难以实现基于动应变的桥梁动挠度精准识别。针对梁式桥梁,本文提出了一种基于应变模态的桥梁动挠度识别方法,其特征是利用应变传感器对振动的梁结构进行应变测试获得动应变数据,由动应变数据的互相关函数求出应变模态振型,利用应变-位移转换关系求出位移模态振型,再由动应变数据和应变模态振型计算出位移模态坐标,最后根据计算出的位移模态坐标叠加位移模态振型得到梁结构的实时挠曲线,从而实现对动挠度的识别。为了验证方法的有效性和适用性,本文分别对简支梁、连续梁在脉冲激励、地震荷载以及移动荷载作用下的动挠度进行了数值模拟,并进行了简支梁力锤锤击实验。针对移动荷载作用下桥梁的动挠度,本文结合了解析模式分解理论,实现基于应变模态的实时识别。所有数值模拟及实验的结果表明,基于应变模态识别桥梁动挠度是可行的,并且具有较高的精度。
[Abstract]:In bridge health monitoring, bridge deflection, as a description of structural deformation, can be used to evaluate the quality and operation state of the bridge, and to reflect the stiffness of the bridge, especially the dynamic deflection of the bridge. It is the most real-time embodiment of bridge deformation, so it is of great significance to monitor the dynamic deflection of bridge. In recent years, the bridge deflection measurement method. The method of strain based on strain has been paid more and more attention. At present, the method of identifying bridge deflection based on strain testing is mainly based on mean curvature method. Based on the least square curve fitting method and conjugate beam method, these methods have been applied to identify the static deflection of bridges, but for the dynamic deflection identification of bridges. Because the static deflection recognition principle only considers the static strain-displacement relation and does not consider the influence of the bridge vibration, it is difficult to realize the accurate identification of the dynamic deflection of the bridge based on the dynamic strain. A bridge dynamic deflection identification method based on strain mode is proposed in this paper, which is characterized by the use of strain sensors to obtain dynamic strain data by strain measurement of vibrating beam structures. Based on the cross-correlation function of the dynamic strain data, the mode shape of the strain mode is obtained, and the mode shape of the displacement mode is obtained by using the strain-displacement transformation relation, and then the displacement modal coordinates are calculated from the dynamic strain data and the strain modal mode. Finally, according to the calculated displacement modal coordinates superimposed displacement modal mode to obtain the real-time deflection curve of the beam structure, so as to realize the identification of dynamic deflection. In order to verify the effectiveness and applicability of the method, this paper separately for simply supported beam. The dynamic deflection of continuous beam under impulsive excitation, seismic load and moving load is numerically simulated, and a simple beam hammer hammering experiment is carried out, aiming at the dynamic deflection of bridge under moving load. This paper combines the theory of analytical mode decomposition to realize the real-time identification based on strain mode. The results of all numerical simulations and experiments show that it is feasible to identify the dynamic deflection of the bridge based on the strain mode. And it has high precision.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U446

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