Welding Process Design And Joint Fatigue Strength Evaluation System For High Speed Bogies

High speed bogie is one of the most important load bearing structures of rolling stock. Strength reliability of bogie has a great influence on the overall safety and running stability of the rolling stock.High speed bogie is a typical welding structure which is very weak in the welded joint part, and joint fatigue failure is a common failure mode of it.Welding process design and evaluation of fatigue strength are the keys to ensure the welding quality of high speed bogie.According to the actual demand of the enterprise, this paper designed and developed a high speed bogie welding process design and joint fatigue strength assessment system.First of all, according to the characteristics of welding process design and fatigue strength evaluation of high speed bogie, the paper finished the classification of system knowledge and designed of the knowledge acquisition and expression method of each type of knowledge. The whole structure of the system knowledge base is formed.According to the process of solving the problem, the principle and process of the system inference mechanism is designed. By y analyzing the overall function of the system, the whole structure design of the system is completed.Secondly, according to the main work content of the high speed bogie welding process design, combined with the relevant standards and experience of the research, the paper formed the welding process design process. By studying the method to determine the parameters of welding process, the process design scheme is established. And the process design is achieved through the multi-layer reasoning process.Moreover, according to the principle of the nominal stress evaluation method of welded joints fatigue strength,the flow and module structure of the system fatigue strength evaluation are designed. This system using the rain-flow counting method to analysis the nominal stress spectrum and a program for the matching of fatigue quality grade of joints is developed to get the S-N characteristic curve of the joint.The system achieved the evaluation of fatigue strength of joints with different fatigue assessment methods.Finally, under the premise of ensuring the extensible property and security of knowledge base, the realization method of knowledge base management system and the method of knowledge base security protection are designed. And a complete system of knowledge base management system is established, which ensures the continuous learning of the system knowledge base and the characteristics of the expert system knowledge base.