公铁两用双层桥梁风屏障气动机理及优化研究

发布时间：2018-05-09 20:15

本文选题：公铁两用双层桥梁 + 风屏障　；参考：《西南交通大学》2017年博士论文

【摘要】：随着我国交通运输网络逐渐向强风场地区延伸,风致车辆事故频发。公铁双层桥梁,由于其结构相对复杂,绕流加速效应明显,桥上车辆的行车环境将进一步恶化。在桥面设置风屏障是提高车辆行车安全性的有效措施之一,但风屏障又会改变桥梁本身的抗风性能。本文围绕公铁两用双层桥梁风屏障的气动机理及优化开展了如下研究:首先,通过风屏障足尺模型风洞试验,测试了风屏障后方的流场分布特性及其自身风荷载,对比分析了风屏障开孔形式及开孔孔径对流场特性的影响,明确了不同风屏障在来流方向及竖向上的有效防风范围,通过侧向力及倾覆力矩等效原则,得到了不同风屏障后方的等效风速。进一步,提出了适用于多孔形风屏障及纵条形风屏障的数值模拟方法,基于风屏障足尺试验结果,验证了该模拟方法的可靠性。在此基础上,研究了多孔形风屏障透风率分布,纵条形风屏障障条排数和障条空间形状等孔型参数对其后方流场特性的影响,并提出了相对较优的参数取值。其次,将风屏障、车辆及双层桥梁作为一个系统进行了缩尺模型风洞试验,测试了双层桥梁上下桥面设置风屏障前后的局部风场,讨论了风屏障对CRH2列车和公路大货车气动力系数的影响。在此基础上,采用风-车-桥耦合振动分析方法,计算了大货车及列车的动态响应,分析了不同车道位置、风速、车速以及风屏障对车辆的行车安全性及舒适性的影响。再次,针对公铁两用桁架桥梁,测试了设置风屏障前后桥梁的静力三分力系数、颤振临界风速以及涡振响应,讨论了风屏障对主梁静动力气动特性的影响。针对分离式双层箱梁桥,通过对比分析单独铁路桥梁和公铁双层桥梁上轨道上方的流场特性及列车气动力,明确了双层桥面间的气动干扰效应。进一步,通过改变分离式双层桥梁的间隔高度,得到不同间隔高度下,铁路桥面流场特性和列车的气动力系数变化规律,提出了设置风屏障前后,双层桥梁间隔高度的建议值。最后,综合考虑车辆及桥梁的安全性,将风屏障防风效果的优化问题转化成了一个多目标优化问题,并利用NSGA-Ⅱ多目标优化算法对风屏障进行了优化,在此基础上,采用数据包络分析方法对多目标优化算法所得Pareto最优解集进行方案比选,得到了风屏障最优方案。结果表明:足尺模型风洞试验结果可为日后该类风屏障的优化设计和数值模拟提供相对标准化的参考数据。本文提出的适用于多孔形风屏障的二维模拟方法可较好地模拟该类风屏障。风屏障的透风率分布、障条排数及障条空间形状对其后方一定范围内的流场影响较为明显,在今后的风屏障优化设计研究中应该予以一定的重视。对双层桁架桥梁的研究结果表明,风屏障会导致车桥组合状态下,主梁阻力系数增加,升力系数降低。设置风屏障后,主梁颤振临界风速降低明显,这说明风屏障会导致该桁架桥的颤振稳定性降低;主梁的涡振响应得到了明显的抑制,这说明风屏障在一定程度上可以作为抑制该类主梁涡振的气动措施。对分离式双层箱梁桥的研究结果表明,设置风屏障会增加上下桥面间的气动干扰效应,无风屏障时,双层桥面间隔高度仅需满足基本建筑界限即可,设置风屏障以后,当间隔高度≥15m时,铁路桥面风速剖面以及迎风侧轨道处列车气动力变化趋于平缓。针对风屏障防风效果的多目标优化问题,结果表明:采用NSGA-ⅡDEA混合算法对风屏障进行多目标优化是可行的,该优化设计方法为风屏障优化问题提供了一种新思路。
[Abstract]:With the gradual extension of traffic and transportation network to the strong wind field area, the wind-induced vehicle accidents occur frequently. The double deck bridge of the public rail is more complicated, the acceleration effect of the flow around the bridge is obvious, and the driving environment on the bridge will be further deteriorated. The wind resistance mechanism of the bridge itself is changed. The aerodynamic mechanism and optimization of the double double deck bridge wind barrier are studied in this paper. First, through the wind barrier full scale model wind tunnel test, the flow field distribution characteristics and its own wind load behind the wind barrier are tested, and the open hole form and opening aperture convection field of the wind barrier are compared and analyzed. The effective wind protection range of different wind barriers in the direction and vertical direction of the wind barrier is clarified, and the equivalent wind velocity behind the different wind barriers is obtained by the equivalent principle of lateral force and overturning moment. Further, the numerical simulation method is put forward for the porous wind barrier and the longitudinal bar type wind barrier, based on the full scale test knot of the wind barrier. The reliability of the simulation method is verified. On this basis, the influence of the porosity distribution of the porous wind barrier, the number of bar row number and the shape of the barrier strip on the characteristics of the rear flow field is studied, and the relative optimum parameters are put forward. Secondly, the wind barrier, the vehicle and the double deck bridge are used as a system. A scale model wind tunnel test is carried out to test the local wind field before and after the wind barrier in the upper and lower deck of a double deck bridge. The influence of the wind barrier on the aerodynamic coefficient of the CRH2 train and the highway large truck is discussed. On this basis, the dynamic response of the large freight car and the train is calculated by the wind vehicle bridge coupling vibration analysis method, and the different vehicles are analyzed. The effect of channel position, wind speed, speed and wind barrier on vehicle safety and comfort. Again, the static three force coefficient, critical wind speed and vortex response of the bridge were tested before and after the wind barrier, and the influence of wind barrier on the dynamic aerodynamic characteristics of the main Liang Jing was discussed. By comparing and analyzing the characteristics of the flow field above the track on the track of a single railway bridge and the double deck bridge and the aerodynamic force of the train, the aerodynamic interference effect between the double deck bridge is clearly defined. Further, the characteristics of the flow field of the railway bridge and the aerodynamic force of the train are obtained by changing the interval height of the separate double deck bridge. The proposed value of the interval height of the double deck bridge before and after the wind barrier is set up. Finally, considering the safety of the vehicle and the bridge, the optimization problem of wind barrier effect is transformed into a multi-objective optimization problem, and the NSGA- II multi-objective optimization algorithm is used to optimize the wind barrier. On this basis, the optimization of the wind barrier is adopted. Using the method of data envelopment analysis, the optimal solution of the Pareto optimal solution set by the multi-objective optimization algorithm is selected and the optimal scheme of the wind barrier is obtained. The results show that the results of the full scale model wind tunnel test can provide relatively standardized reference data for the optimization design and numerical simulation of the wind barrier in the future. This paper is suitable for the porous wind. The two-dimensional simulation method of barrier can simulate the wind barrier better. The distribution of wind barrier, the number of barrier rows and the shape of the barrier space have obvious influence on the flow field in a certain range behind it. The study on the optimization design of the wind barrier in the future should be paid attention to. The results of the Double Deck Truss Bridge show that the wind barrier is the barrier. Under the condition of the bridge combination, the drag coefficient of the main beam increases and the lift coefficient decreases. After setting the wind barrier, the critical wind speed of the main beam decreases obviously, which indicates that the wind barrier will lead to the decrease of the chatter stability of the truss bridge, and the vortex vibration response of the main beam is obviously suppressed, which shows that the wind barrier can be used as a restraint to some extent. The results of the study on the vortex vibration of the main beam. The results of the study on the split double deck box girder bridge show that the wind barrier will increase the aerodynamic interference effect between the upper and lower deck. When the barrier is no wind barrier, the height of the double deck bridge interval is only to meet the basic building boundaries. The aerodynamic change of the train at the wind side track tends to be slow. In view of the multi-objective optimization problem of wind barrier effect, the results show that it is feasible to use the NSGA- II DEA hybrid algorithm to optimize the multi target of the wind barrier, and the optimization design method provides a new idea for the optimization of the wind barrier.

【学位授予单位】：西南交通大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：U443.7

【参考文献】