基于随机车辆荷载的车桥耦合数值分析

发布时间：2018-05-26 15:00

本文选题：CA交通流模型 + 随机变速运动　；参考：《江西理工大学》2017年硕士论文

【摘要】：随着既有桥梁的不断老化以及道路车辆数量的不断增多,桥梁开始接受新时代的洗礼。桥梁实际运营中涉及到的车桥振动问题一直是工程领域研究的热点,过度的车桥振动容易导致桥梁出现过早的损伤。目前的车桥振动研究大部分集中在车辆做匀速运动或者匀变速运动,而较能反映实际车流情况的车辆做随机变速运动却较少涉及。本文就是以此为出发点,通过结合江西省交通厅科技项目“混合交通流及其在亚健康桥梁承载力评估中的应用研究”(项目编号:2014Y0012)和江西省教育厅科技项目“多阻尼空间排布对随机车辆荷载下桥梁优化减振机制研究”(项目编号:GJJ160620)以实测得到的广韶高速车流荷载信息为基础,考虑车辆做随机变速运动时车桥耦合振动的相关特性。研究的内容主要从以下几个方面展开:(1)介绍元胞自动机(CA)模拟交通流的相关理论并在考虑车辆做随机变速运动时引入它的加减速和随机变道原则;将实测的车辆荷载信息通过MATLAB拟合整理得到实际车辆荷载的分布函数并以此建立随机车辆荷载数据库,该数据库将为多车辆考虑随机变速运动时随机赋予车重给每一辆入桥的车辆。另外在ANSYS进行车桥耦合分析时利用CA模型处理收集得到的实测车辆荷载信息并赋予它实时变换位置的命令模拟车辆在桥面行走的情况。(2)通过单车辆车桥耦合振动理论结合CA模型的相关理论并利用MATLAB建立单车辆随机变速运动下的车桥耦合振动程序并与单车辆匀速运动时得到的数值结果进行对比分析。其中车重均用定值表示,桥面不平顺情况用较为成熟的AR模型来模拟。通过改变若干个车桥耦合振动中的参数对参数进行敏感性分析。结果表明:匀速运动与随机变速运动都在车重、刚度和桥长这些参数有较规律的参数敏感性。其中随机变速运动时,在控制车辆下车体振动幅度和桥梁跨中最大挠度上以车速维持在7-25m/s行驶最佳;车重为17.5t时车辆下车体的振动幅度最小,而桥梁最大竖向挠度则是随着车重的增大单调递增但车重为22.5t时对桥梁造成的冲击最小;分析桥面不平顺影响时并没有一致的规律,但以桥面不平顺系数为1.1时车辆下车体振动幅度和最大竖向挠度最小;而在桥梁刚度增大时,下车体的上下振动幅度逐渐增大,桥梁最大竖向挠度则是逐渐递减但以桥梁刚度为2.600e11N.m2时对桥梁造成的冲击最小;另外当桥长增大时,车辆下车体的振动幅度单调递增,桥梁最大竖向挠度也随桥长增大单调递增且对桥梁造成的冲击也是如此变化规律。(3)通过多车辆车桥耦合理论利用同样的方法建立多车辆随机变速运动下的车桥耦合振动程序并与多车辆匀速运动时的结果进行对比分析。其中匀速运动时车重采用定值表示,而随机变速运动时的车重利用随机车辆荷载数据库对任一驶入桥梁的车辆进行赋值进而实现随机车辆荷载作用下的车桥耦合振动分析并且其在实际随机变速运动中实现随机入桥、随机加减速、随机变换道。然后改变若干个车桥耦合振动中的参数对参数进行敏感性分析,其中随机变速运动中由于生成图的规律不明显增加了数值的概率密度分析的内容。数值分析结果表明:匀速运动与随机变速运动都在车重、刚度和桥长这些参数有较规律的参数敏感性。其中随机变速运动时,车辆下车体上下振动幅度几乎是随着车重均值的增加而单调递增。分析桥梁跨中位移时,随着车重均值的增大,同样概率密度发生的位移区间不断扩大。另外跨中最大竖向挠度也随着车重均值的增大逐渐增大;而桥梁最大竖向挠度在桥梁刚度呈现一致的敏感性,都随着刚度的增大而增大。在分析桥长影响时,当其单调增大时,下车体上下振动幅度和桥梁最大竖向挠度都呈现一致的敏感性,都单调递增。另外无论改变哪种参数,桥梁最大位移发生位置有超过0.8的概率密度集中在桥梁位置为12-~20m的区间,车辆下车体振动幅度发生在-0.05m~0.05m区间也是0.8的概率密度。(4)最后在ANSYS中将AR模型模拟的桥面不平顺通过离散点的形式建立桥面铺装部分并与桥梁主要结构模型结合建立包含桥面不平顺情况的桥梁结构有限元模型,再将实测的一段随机车辆荷载信息经过MATLAB处理后代入ANSYS作车桥耦合分析。通过ANSYS模拟得到的结果可以看出在MATLAB进行多车辆随机变速运动下的车桥耦合数值分析得到的结果有一定的合理性。
[Abstract]:With the continuous aging of existing bridges and the increasing number of road vehicles, the bridge began to accept the baptism of the new era. The problem of bridge vibration involved in the actual operation of the bridge has always been a hot spot in the field of engineering research. Excessive axle vibration is easy to cause premature damage to the bridge. In this paper, this paper is based on the "mixed traffic flow and its application in the assessment of the bearing capacity of subhealthy bridges" (project number: 2014Y0, 2014Y0). 012) and the science and technology project of Jiangxi Provincial Education Department, "study on the mechanism of multi damping space arrangement to the optimal damping mechanism of bridge under Random Vehicle Load" (project number: GJJ160620), based on the measured load information of the Guangzhou Shaoguan high-speed vehicle, considering the related characteristics of vehicle bridge coupling vibration during random variable speed motion. The following aspects are as follows: (1) introducing the theory of cellular automata (CA) simulation of traffic flow and introducing the principle of acceleration and deceleration and random variation of the vehicle when considering the vehicle's random variable motion. The measured vehicle load information is fitted by MATLAB to get the distribution function of the actual vehicle load and to establish the random vehicle load data. The database will give vehicle weight to each vehicle randomly when considering the random variable motion for multiple vehicles. In addition, when ANSYS is used to analyze the vehicle bridge coupling analysis, the CA model is used to process the measured vehicle load information and give it the real-time transformation position to simulate the vehicle's walking on the bridge deck. (2) through a single vehicle. The coupling vibration theory of vehicle bridge combined with the related theory of CA model and uses MATLAB to establish the coupling vibration program of the vehicle bridge under the random variable speed motion of a single vehicle and compared with the numerical results obtained by the single vehicle at uniform speed. The weight of the vehicle is all expressed with the fixed value, the unevenness of the bridge deck is simulated with a more mature AR model. The parameters in the coupling vibration of several vehicle bridges are changed to the sensitivity analysis of parameters. The results show that both the uniform velocity and the random variable motion have a more regular parameter sensitivity to the weight, the stiffness and the length of the bridge length. In the random variable motion, the speed of the vehicle's vibration amplitude and the maximum deflection of the bridge span are maintained at the speed of vehicle. It is the best driving in 7-25m/s; the vibration amplitude of the vehicle body is the smallest when the weight is 17.5t, and the maximum vertical deflection of the bridge is the minimum impact on the bridge when the weight increases monotonously but the weight is 22.5t, and there is no consistent rule when analyzing the impact of the bridge surface irregularity, but the vehicle gets off when the bridge surface irregularity coefficient is 1.1. The vibration amplitude and maximum vertical deflection of the body are minimal, but when the bridge stiffness increases, the upper and lower vibration amplitude of the lower body increases gradually. The maximum vertical deflection of the bridge is gradually decreasing but the bridge stiffness is 2.600e11N.m2, and the vibration amplitude of the vehicle body is increasing monotonously when the bridge length increases. The maximum vertical deflection also increases monotonously with the length of the bridge and the impact is also so changing. (3) the coupling vibration program of the vehicle bridge under the multi vehicle random variable motion is established by using the multi vehicle bridge coupling theory and the results are compared with the results of multiple vehicles at uniform velocity. The weight of the vehicle is represented by the fixed value, while the weight of the random variable speed moving vehicle uses the random vehicle load database to assign a vehicle to the bridge, and then realizes the coupling vibration analysis of the vehicle bridge under the random vehicle load, and it realizes random entry bridge, random acceleration and deceleration and random transformation in the actual random variable motion. The parameters in the coupling vibration of several vehicles and bridges are changed to the sensitivity analysis of the parameters. In the random variable motion, the law of the generating graph does not increase the content of the probability density analysis. The numerical analysis shows that both the uniform velocity and the random variable motion are both in the weight, the stiffness and the length of the bridge length. With the increase of the mean of the weight of the vehicle, the displacement interval of the same probability density increases with the increase of the mean of the weight of the vehicle, and the maximum vertical deflection of the middle span also gradually increases with the increase of the mean value of the vehicle weight. The maximum vertical deflection of the bridge increases with the stiffness increasing. When the bridge length affects the bridge length, when the bridge length is enlarged, the upper and lower vibration amplitude and the maximum vertical deflection of the bridge are all with the same sensitivity. More than 0.8 of the probability density of the displacement is concentrated in the interval of the bridge position of 12-~20m, and the vibration amplitude of the vehicle is also 0.8 of the probability density in the -0.05m~0.05m interval. (4) at last, the bridge deck is unsmoothed through the discrete point in the form of the AR model, and the bridge main structure model is formed in the form of the discrete point in the ANSYS model. The finite element model of bridge structure containing bridge surface irregularity is established, and then the measured load information of a random vehicle is treated by MATLAB to ANSYS as a vehicle bridge coupling analysis. The results obtained through the ANSYS simulation can show the result of the numerical analysis of the bridge coupling under the multi vehicle random variable motion of MATLAB. There is a certain degree of rationality.
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U441.3

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