Study On Dynamic Stress Response And Damage Of Frame Under High Frequency Excitation

With the continuous improvement of train running speed and the increase of operating mileage in China,the vibration between various structural components of the vehicle is intensified.Due to continuous wear and other reasons,high-speed train wheels will produce polygons of different order and magnitude at different stages of wear.It will cause a higher excitation frequency and close to the natural frequency of some parts of the frame,which will easily lead to resonance or local resonance of the structure,increase the dynamic stress response on the frame,and reduce the service life of the frame.In this thesis,the CR400BF bogie frame is taken as the research object.Through the bench strain mode simulation and the small wheel high frequency disturbance bench test,the following research is carried out;(1)Establish the finite element model of the constraint state of the frame,perform the simulation calculation of the strain mode,analyze the directional strain and mode shape of each mode,and obtain the strong response position and frequency of the frame strain,which is the position of the bench test patch.Select to provide a reference.(2)Combining the characteristic frequency of the wheel-rail excitation of the typical line and the amplitude range of the wheel polygon,and formulating a test scheme for high-frequency excitation using the small roller;combining the frame strain modal analysis and the measured dynamic stress results of the line,the framework is determined.The measuring point part;the simulation of different static loading,different polygon amplitude,different frame end structure,small roller high-frequency excitation rack test,and real-time acquisition obtained the movement of each measuring point in each test condition stress.(3)Analyze and compare the different static loading,the amplitude of different polygons,the equivalent stress of each measuring point of the frame under the auxiliary mounting seat at the end of the frame,and obtain the dynamic response region of the frame under various working eonditions;from the time domain and the frequency domain The signal of each measuring point in the dynamic stress response area is processed,and the dynamic stress characteristics of each measuring point and its relationship with the excitation frequency and the natural frequency are analyzed according to the frequency sweeping test results of each measuring point;the bench test result and the strain mode simulation are simulated.Compared with the line dynamic stress test results,the influence of high frequency disturbance on the stress response of the frame measurement point is obtained.(4)Analyze and select the damage assessment methods in the frequency domain,calculate the damage of each measurement point in the frame under high frequency disturbance,and compare with the damage calculation results in the time domain to verify the feasibility of damage assessment in the frequency domain.114 pictures,17 tables,72 references.