【作者】 张永昌；

【导师】 徐宇工；

【作者基本信息】 北京交通大学 ， 动力机械及工程， 2012， 硕士

【摘要】 高速列车运行速度不断提升,由此而产生的空气动力学问题也日益突出,气动载荷对列车车体以及其附属装备的影响愈加明显。位于列车车下设备舱两侧的裙板是保护车下吊装设备,减少车身空气阻力的重要装备。我国高速列车运行时间较短,但已发现连接裙板与车身的支架出现疲劳开裂现象,对列车行驶造成了极大的安全隐患。因此对裙板所受气动载荷的作用方式和裙板及支架的结构响应进行研究分析对于解决裙板支架疲劳破坏问题、提高高速列车行驶安全性能具有重要意义。本文讨论了裙板支架承载的特点,确定气动载荷为引起裙板支架疲劳破坏的主要原因。通过对绕流问题基本算例的研究,探究了稳态条件下流体对固体产生非稳态影响的原理。计算结果表明：一定条件下,流体流经非流线形固体表面时边界层发生分离,不断脱落的涡团使得尾流处压力发生交替变化,对固体结构产生交变影响。以CRH3型高速列车为研究对象,建立了包括列车车外流场、设备舱内流场、裙板及其支架固体结构的流固耦合计算模型。对列车明线行驶以及强侧风环境中行驶两种典型运行工况下的流场进行了数值模拟计算,得到了不同工况下设备舱内外流场的分布情况,分析了不同位置的裙板所受气动载荷的产生原因及其变化规律。研究了列车行驶速度、强侧风风速对上述结果的影响。建立裙板及支架的有限元模型,将流场模拟所得裙板内外表面压力以外载荷的形式施加于裙板及支架的结构仿真计算中,对裙板及支架结构进行承载分析。得到了明线行驶工况、强侧风行驶工况下裙板及支架的应力分布及其变化情况。以裙板支架的筋板连接处为研究重点,分析了不同裙板、不同位置支架筋板连接处所受应力值及其变化规律的差异,以及工况参数对裙板及支架承载的影响。通过与实测结果进行对比,验证了仿真结果的正确性。更多还原

【Abstract】 With the running speed promoting, aerodynamic problems of High-speed trains have become increasingly prominent and the influence of aerodynamic load on trains and their affiliated equipment has been more obvious. Skirt boards locate at both sides of the equipment cabin for protecting the equipment which is installed at the bottom of the car and reducing air drags. Although it has been such a short time since Chinese High-speed trains came into service, cracks have been found on supports which are used to connect the car and the skirt boards. And this phenomenon could cause hidden danger of High-speed trains. So it is significant to investigate the action mode of aerodynamic load to a skirt board and structures response for protecting supports of skirt boards from fatigue failure and improving safety performance of high-speed trains.Skirt board supports bearing characteristic is discussed. Aerodynamic load is considered to be the main factor that causes fatigue failure of skirt board supports. By studying a basic example, principle of unsteady influence from fluid to solid under steady boundary condition is explored. Result shows that boundary layer separates when fluid flows around a non-streamlined body. Vortex blob falls off the body and causes pressure changing in wake flow and alternating influence to solid.By selecting CRH3High-speed train as the research object, FSI calculation model is established. This model contains the fluid model of air outside the train and inside the equipment cabin and the structure model of the skirt boards and their supports. Flow condition is simulated under working conditions of High-speed trains running in open air and strong side-wind. Flow distribution of air inside and outside the equipment cabin is obtained. Cause and variation regulation of aerodynamic load to skirt boards is analyzed and Influence of trains speed and wind speed on simulation result is studied.Finally, finite element models of skirt boards and supports are built. To analysis structures response pressure at both sides of the skirt boards which was calculated in fluid simulation is applied. Stress distribution and variation regulation of skirt boards and their supports are obtained under different working condition. On the basis of key research on rid plates connection on skirt board supports, value and variation regulation of stress at different skirt boards and position is studied. The influence of working condition parameters(trains speed and wind speed) on structural response is analyzed. The results of simulation were tested by comparing with the measured results.更多还原