The Mechanical Properties Analysis Of Railway Wagon Under The Action Of Granular

The trend of railway transportation is high-speeding and heavy-loading transportation,so much of the recent research focus has been on the method of how to attain high strength,light weight and heavy load of railway wagon.However,the mode of transportation mentioned above will bring larger vibration intensity and wider frequency range to the wagon.The wagon will show a complex dynamic response under the nonlinear action of granular media,so the deformation of bending and torsion will increase,and the probability of damage will also increase.These complex characteristics of granular media increase the design difficulty of new wagon,and become a limiting factor of the railway transportation development.The current domestic and foreign criterions obviously do not meet the development demand of a new wagon.So the statics and dynamics research on heavy-loading wagon have important implications.Combined with enterprise needs,this article takes a kind of gondola car as the research object and researches medium and gondola car coupling system from statics and dynamics aspects by the method of theoretical analysis,numerical analysis and experimental analysis.The conclusion provides a theoretical foundation for the design of the wagon.The key problem in the design of heavy haul train is how to calculate the strength problems of wall,including studies on statics and dynamics problems.So this article focuses on lateral pressure on the end wall and side wall,and dynamic studies on granular media-wall coupling system.The research contents are as follows:1.The dynamic characteristic of a wagon end wall is investigated in detail.The theoretical dynamic model of a wagon end wall was built which considers the influence of granular media.The model is based on von-Karmen theory,and special mechanical properties of granular are considered.According to the model,the effect of key design parameters on mechanical properties of the structure was studied.The reliability of the model can be verified by comparison with the FEM result.It can provide a critical reference for the design of the wagon.2.Considering the influence of mechanical characteristics of the end wall,a new analytical method for calculating the lateral pressure is introducing.Rock and Soil Mechanics.For the end wall: It can provide a basis for lightweight design by deducing an analytical method of the lateral pressure which is closer to the experimental results,considering the soil arch effect and the size of the wall by Mohr's circle theory and limit equilibrium theory.For the side wall: Calculation formula was derived which takes the rotating wheel as rupture surface.The correctness of the formula was verified by comparison with experimental results.The nonlinear distribution of lateral pressure along the height direction is achieved.Further research was done for the relationship between key parameters of the heavy haul wagon design and the lateral pressure on the side wall.3.The experimental method of medium and structure coupling system is investigated in detail.The modal test method of granular container is discussed based on a model geometric similar to carriage.More researches about the influence of the modal characteristics of the structure under the action of granular and different excitation is done.The results guided the modal test of a heavy haul wagon.Some solutions on the mechanical properties of the wagon were presented.It proves that pre-experiment analysis can ensure the accuracy of measurement points and excitation points and improve the accuracy of the experiment result.Vibration table excitation is more suitable for the modal experiment of the wagon.It proves that the natural frequency decreases and the main vibration mode changes from elastomer vibration mode into rigid body modes along with the increasing of the medium.4.Research on heavy haul wagon by the finite element method is done.The impact that the bogie has on modal characteristics of wagon is studied from two aspects: the rigid vibration modes and elastomer vibration modes first.It offers reference for the similar model of vehicle engineering.The article presents a finite element simulation method,and its correctness can be verified by comparison of the modal test results.Then the impact of granular media on modal of wagon was discussed: the presence of granular media makes the frequency of the same vibration modes reduce,and the number of elastomer vibration modes is significantly decreased.The results are consistent with the conclusion of the experiment above.And it provides new ideas for finite element simulation of the heavy haul wagon.