Based On The Random Decrement Technique To Identify The Bogie Frame Rigid Body Modal Study

Railway transportation is the main way of transportation in China.From 1997,the speed of the train has increased rapidly.With the increasement of train speed ,how to make sure that the train moves stably is an important problem .The frame is the important part of the bogie and the important structure that endures load . The stability of the frame is very important to the moving stability of the train .So the vibration of the frame is worth researching .The contents of this paper can be summarized as follows :1.This paper summarized the methods of modal identification under ambient excitation and discussed the researching status .The random decrement technique is decided to use to identify the modal parameters of the frame .2.CW-200 bogie frame is the researched frame .We measured the vertical and lateral vibration acceleration of the frame's four measured points .3.With the help of matlab,acceleration response signal of free vibration are separated from those responses obtained from ambient excitation by using the random decrement technique .The frequency of the acceleration response signal of free vibration is obtained. By comparing the acceleration response signal of the four measured points ,the vibration form are finded .