Identification Of Aerodynamic Load To Skirt Boards By Simulating And Analysis Of Structures Response For A High-speed Train

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.