车桥耦合系统下呼吸裂缝的非线性损伤识别方法

发布时间：2017-12-26 20:28

本文关键词：车桥耦合系统下呼吸裂缝的非线性损伤识别方法　出处：《重庆大学》2016年硕士论文　论文类型：学位论文

【摘要】：混凝土简支梁桥是我国中、小桥梁中应用最为广泛的桥型,而混凝土开裂是其常见病害之一。由于该类桥梁具有量大面广,结构形式简单等特点,无法像大型复杂桥梁一样建立监测参数全、测点多的桥梁健康监测系统,所以如何根据该类桥梁运营状态下的动力响应特征,简单、高效地实现其损伤识别,无疑具有一定的工程实用价值。本文根据试验观测到裂缝在振动过程中将出现张开—闭合循环的呼吸效应,建立了基于曲率控制指标的曲线型呼吸裂缝模型并将其融入车桥耦合振动系统中,通过理论推导和裂缝出现后车桥耦合系统加速度响应信号分析,提出了基于能量指标的简支梁开裂非线性损伤识别方法,在运营状况下采用少量传感器即可识别混凝土简支梁桥的开裂损伤。论文的主要研究内容和结果如下:(1)编制了含呼吸裂缝的车桥耦合振动系统的计算程序。选取半车模型和欧拉梁模型,根据相互作用力原理编制了车桥耦合振动的动力计算程序。选取曲率曲线型呼吸裂缝模型,并通过刚度折减方式加入车桥耦合振动计算程序中。通过与已有文献计算结果的对比验证了编制程序的可靠性。(2)改进了HHT方法中的缺陷。针对端点效应和模态混叠2大缺陷,分别采用端点镜像延拓法和EEMD分解法进行改进。通过算例分析表明,改进后的HHT能更为准确地处理车桥耦合振动的加速度响应信号。(3)提出了运营状态下简支梁桥裂缝的非线性损伤识别方法。分析了混凝土简支梁开裂振动信号的能量在时频域的分布规律,结合理论推导建立了基于能量指标的裂缝非线性损伤识别方法。数值算例结果表明,所提损伤识别方法通过1个传感器信号即能实现裂缝有无、部位和损伤相对程度的判定。(4)探讨了所提损伤识别方法的实用性。通过数值模拟算例研究了不同噪声、不同车辆状况、不同环境温度以及多裂缝情况下所提方法的性能,结果表明噪声、车重、车辆类型和环境温度对所提方法在裂缝有无、部位和程度识别方法的影响较小。车速对损伤程度的判定影响较大且车速过大也将影响多裂缝下的识别效果。(5)优化了传感器的布设。基于整体最优原则,即损伤幅值比在各损伤位置工况下,均值越大、方差越小、有效监测点越多,整体越优。综合以上3个方面,计算传感器优化系数,结果表明跨中点为传感器最优布置点。
[Abstract]:The concrete simple supported beam bridge is the most widely used bridge type in the middle and small bridge beams in China, and the concrete cracking is one of the common diseases. Because of this kind of bridge has a large volume, features simple structure, not as large and complex bridges like the establishment of monitoring parameters, multiple measuring points of the bridge health monitoring system, so according to the dynamic response of the bridge under operation condition, simply and effectively realize the damage identification, it has practical engineering a certain value. According to the experimental observation to crack open - closed cycle breathing effect in vibration process is established based on the curve of respiratory control index of curvature crack model and its integration into the vehicle bridge coupling vibration system, through the analysis of the acceleration signal of vehicle bridge coupling system response theory and put forward after the crack beam cracking nonlinear damage identification method based on energy indexes, using a small number of sensors can identify the cracking damage in concrete bridge under operation condition. The main contents and results of this paper are as follows: (1) a program for calculating the coupled vibration system of a car and bridge with respiratory cracks is compiled. The semi vehicle model and Euler beam model are selected, and the dynamic calculation program of the coupling vibration of the vehicle bridge is compiled according to the interaction force principle. The curvature curve type of respiratory crack model is selected and the stiffness reduction method is added to the bridge coupling vibration calculation program. The reliability of the program is verified by comparison with the existing literature. (2) the defects in the HHT method are improved. In view of 2 defects of endpoint effect and modal aliasing, endpoint mirror extension method and EEMD decomposition method are used to improve respectively. The analysis shows that the improved HHT can more accurately deal with the acceleration response signal of the vehicle bridge coupling vibration. (3) the nonlinear damage identification method for the crack of simple supported beam bridge in operation state is proposed. The distribution law of the energy of crack and vibration signal of concrete simply supported beam in time-frequency domain is analyzed. Combined with theoretical deduction, a nonlinear damage identification method based on energy index is established. The numerical example shows that the proposed damage identification method can determine the relative degree of damage, location and damage through 1 sensor signals. (4) the practicability of the proposed method of damage identification is discussed. Simulation study on different noise and vehicle condition, different temperature and cracks under the condition of the proposed method through numerical results show that the small noise, vehicle weight, vehicle type and the influence of environmental temperature on the proposed method, no cracks in the position and degree of recognition. The speed of vehicle has great influence on the judgment of damage degree and the oversize of vehicle speed will also affect the recognition effect under multiple cracks. (5) the layout of the sensor is optimized. Based on the overall optimal principle, the greater the mean value, the smaller the variance and the more effective monitoring points, the better the overall optimization of the damage amplitude ratio. Combining the above 3 aspects, the optimization coefficient of the sensor is calculated. The results show that the midpoint is the optimal placement point of the sensor.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U446

【相似文献】