Study On Vibration And Fatigue Of Tank Container Vehicle

With the rapid development of the world economy,the freight industry is becoming more and more important.Under the action of random load for a long time,the tank container truck is prone to fatigue failure.The rationality of its structural design is the key factor to determine the success or failure of transportation.In this paper,the rigid flexible coupling dynamic model is established to analyze the vibration and fatigue of the tank container vehicle.The simulated long life random acceleration load spectrum provided by IEC61373-2010 is used as the random load source of the tank container,and the random vibration fatigue of the tank container is analyzed,the main work contents of this paper are as follows:(1)Based on the finite element method,the tank container vehicle body and container structure are discretized,and the finite element model of the tank container vehicle with weld details is established,and then the rigid flexible coupling dynamic model of the tank container vehicle is established.In order to analyze the relationship between the vibration response and the structural mode of the whole vehicle system under the excitation of track irregularity,the end,front and rear center plates and the middle part of the tank container vehicle are selected as the measurement points,and the acceleration time history and the acceleration power spectral density by Fourier transform are obtained after the dynamic simulation,By analyzing the intersection between the distribution area of energy concentration and the modal frequencies of the first and second order vertical bending,the stability and safety of the tank container vehicle are evaluated.(2)The modal structural stress method,which combines the structural stress method of mesh insensitive mode with the modal synthesis method,is used to analyze the vibration fatigue life of the tank container truck.Firstly,the modal coordinate time history of the tank container truck is extracted from the rigid flexible coupling dynamic simulation results,and then the modal structural stress at the welding toe of each welding line is calculated according to the modal vibration mode of the flexible body,The equivalent structural stress and the change history of equivalent structural stress with time are obtained by superposition of modal structural stress according to the time history of modal coordinates.The rain flow counting method is used to count the change range and frequency of equivalent structural stress,and then the fatigue life of 48 key welds of tank vehicle under heavy load and no-load conditions is evaluated by combining with the master S-N curve.(3)Reference to the China Classification Society Container Inspection Code on the tank container finite element calculation of the load application and other provisions,set up vertical,horizontal,vertical impact resistance related conditions.Using quasi-static method,the static strength of the container is analyzed to determine whether the structure strength of the tank container meets the safety requirements.(4)Based on the IEC 61373-2010 standard simulation long-life random acceleration load spectrum for the vibration conditions,respectively,using the frequency domain structure stress method and the three-interval method to carry out random vibration fatigue analysis of the tank boxing structure Combined with the main S-N curve to analyze the fatigue life and fatigue damage of the weak parts of the weld of the tank container structure,and compare the fatigue damage results of the two methods,the results show that the three-interval method is relatively rough relative to the frequency domain structure stress method,and the statistical method of stress range is relatively rough.The calculation results are conservative(fatigue damage is greater than 0.5),and based on this,local structural improvement is carried out on the larger part of tank container damage,and fatigue life is obviously improved.In this paper,the modal structural stress method and frequency domain structural stress method are introduced into the fatigue life prediction of key welds of vehicle welding structure.They are suitable for different types of welding joints and solve the problem of selecting welding joint S-N curve.This technology can also be applied to the fatigue life evaluation of welding structures in other fields.