Fatigue Evaluation Of Bogie Frame Based On Improved Goodman Curve

Welded structure has the advantages of saving materials,reducing structural weight,simple process,short production cycle,etc.Railway passenger car bogie frame,as a typical welded structure,welded seam is the weak link of fatigue failure,and the fatigue strength of its welded seam position is accurately evaluated The design of the structure is particularly important,and it also provides a guarantee for the safety and reliability of the structure.Based on the above background and reasons,the fatigue assessment methods of domestic welded structures are analyzed and studied,and the Goodman curve method is improved to evaluate the fatigue strength of welded structures.Taking the bogie frame of a locomotive and rolling stock as the research object,the static strength,modal and fatigue strength calculations and analysis are carried out on it,and the main contents are as follows:Firstly,three typical welded joints are established,and the Goodman-Smith fatigue limit diagram converted from multiaxial stress to uniaxial stress is compared with the DVS1612 standard,IIW standard and BS standard.Finally,the Goodman-Smith fatigue limit diagram is obtained to evaluate the weld phase.It is more relaxed than the other three.Aiming at the deficiencies of the Goodman curve method,combined with the SN curve data provided by the BS standard,the Goodman curve is improved by using the symmetrical cyclic fatigue strength of the weld at a fatigue life of 2 million cycles and the safety factor correction provided by the UIC standard for the yield strength.Optimization and re-evaluation of the fatigue strength of the welded joints.The evaluation results show that the safety factor is more conservative and closer to the other three standards.Then take a certain bogie frame as the research object,use the finite element software Hyper Mesh to perform geometric processing and meshing on it,establish a finite element model,apply extraordinary load to the frame according to the UIC515-4 standard,and calculate the steering in combination with the fourth strength theory The safety factor of the frame under static strength conditions is used to study the safety of the bogie frame.Secondly,the related theories of modal analysis are introduced,and the modal analysis of the bogie frame is carried out by using ANSYS software.The analysis based on the calculation results shows that the bogie frame has high rigidity,meets the requirements of locomotives and vehicles,and effectively avoids resonance.phenomenon..Finally,the fatigue load is applied to the frame based on the UIC515-4 standard,and the Goodman-Smith fatigue curve provided by the standard is used to evaluate the fatigue strength of the base material and the key welds,and the welds are compared with the Goodman-Smith fatigue curve optimized in this paper.The results of fatigue strength evaluation are analyzed and compared.The research results provide a reference for the design and evaluation of welded joints of welded structures such as railway rolling stock and its components.