Strength And Fatigue Analyses Of Body Structure Of Diesel Locomotive

The strength, fatigue, random vibration and collision are main aspects to affect the safety and become the basis for the design of the locomotive body. In current work, the diesel locomotive CKDOA is used. Based on the finite element method, the mechanical responses for the strength, fatigue, random vibration and collision analyses are calculated for the comprehensive assessment of the locomotive body.In the first chapter, the development of the diesel locomotive is introduced and the researches from the domestic and foreign scholars in recent years in the static, collision dynamics, fatigue, and random vibration analyses are reviewed. The main contents of this dissertation are then described.In the second chapter, the basic theory of the finite element model of the diesel locomotive body is introduced, including the explicit integral algorithm in the collision dynamics、the expression of the S-N curve and the calculation of the cumulative damage theory, and the random vibration analysis.In the third chapter, the finite element analysis model of the locomotive body is created. With consideration of the design standard at home and abroad, the proposed load condition cases is much closer to the real cases. The stiffness and the strength of the locomotive body are assessed based on the computational results from the finite element model. The dynamic finite element model of the locomotive body is validated with comparison to the experimental test from foreign locomotive body. The deformation in the front cab includes the bending and crushing. The histories of the stress, strain, strength, energy, force, etc. are obtained. Based on the Brown-Miller algorithm and Morrow correction algorithm, the influence of different load cases on fatigue life of the locomotive body is studied. The strength and fatigue life of the weld on the fuel tank bracket is computed by use of the substructure method.In the final chapter, the mode analysis of the skeleton structure is performed and then the random vibration of this structure is simulated with the power spectrum from United States. Then, the vertical and lateral power spectra of the displacement, the velocity and the acceleration at the location of the maximum von Mises stress are obtained. The mechanical responses of the different locations on the locomotive body are analyzed according to the power spectra of the accelerations on the selected 23 hot spots.