Establishment and use method of a database for assessing train body safety

Abstract

The invention provides a database establishing method and a database use method of a database for evaluating train body safety. The database establishing method comprises the steps of determining fatigue safety stress values, stress corrosion threshold values and compression stress values of a welding portion joint area and a base material area through preparing a base material stress testing sample and a joint stress testing sample which correspond with each typical welding portion on the vehicle body; then performing residual stress testing of the typical welding portion for determining safety grade of each welding portion; and correcting the safety grade of the welding portion according to the maintenance period result of the train, thereby establishing the database which can be used for evaluating the safety of the vehicle body. The database can be used for supplying an accurate guiding suggestion on stress state optimization of the train body. In the use process of the database, the residual stress state of the welding portion can be continuously optimized through various kinds of solutions, thereby improving safety grade of the welding portion and providing guidance for production of a next train so that the residual stress state is optimized and safety performance of the vehicle is improved.

Description

technical field [0001] The invention relates to a method for establishing and using a database for evaluating the safety of a train body, belonging to the field of safety evaluation and maintenance of high-speed trains. Background technique [0002] With the rapid development of China's high-speed train rail transit, welding is a key technology in rail transit high-speed trains. The quality of welding also determines the quality of high-speed train vehicles to a certain extent. The level of welding residual stress is an important criterion for evaluating welding quality, because The damage caused by welding residual stress is the main reason for the damage of the joint area. The damage of welding residual stress mainly includes reducing fatigue life, increasing stress corrosion sensitivity, causing instability and deformation of welded structure, and reducing structural rigidity. The body structure of rail transit high-speed trains is complex, the number of welds is large, a...

AI Technical Summary

Problems solved by technology

Complex structures also have obvious differences in the stress state requirements of various positions. For example, the high residual tensile stress of the side walls, ceilings and floors of non-main load-bearing parts usually does not reduce the safety and reliability of the structure. Walls, ceilings, and floors are usually made of thinner aluminum alloy materials. High residual compressive stress usually causes obvious instability and deformation, reducing the dimensional accuracy of the structure; while the underframe structure is the main load-bearing structure, the structure is complex, and The material used is usually 7-series aluminum alloy with high strength, but 7-series aluminum alloy has strong stress corrosion sensitivity, and the high residual tensile stress is likely to cause serious damage to the chassis structure. The residual compressive stress can significantly improve the safety and reliability of the chassis structure

[0003] At present, the research on the residual stress of high-speed trains only stays at the relatively shallow level of the residual stress test of the car body and the simple comparison with the residual stress test results of the previous car body. The complex car body leads to a large amount of residual stress test data, and it is difficult to use scientific and effective methods. It is analyzed and applied, and when residual stress damage occurs, stress treatment is carried out according to the actual situation, and a prevention plan cannot be formulated