by The service reliability of key components of high-speed trains is one of the core factors restricting the development of high-speed trains.
The fatigue life prediction and performance optimization of key components of high-speed trains are the key problems to be solved urgently.
However, the optimization of material fatigue performance mostly stays at the stage of “trial and error”, which is not only time-consuming and laborious, but also difficult to ensure the optimization effect.
Although there are many kinds of fatigue life prediction software, there is still a lack of similar commercial software in China.
At the same time, the service safety evaluation of key components of high-speed trains in China lacks the theoretical support of material fatigue performance prediction and optimization, the relevant international standards are complex, the evaluation methods are difficult to quickly popularize in enterprises, and the performance data and related parameters are obtained from foreign materials and process conditions, which leads to the problem of “acclimatization” in China.
Zhang Zhefeng, a researcher of Institute of metals, Chinese Academy of Sciences, led the material fatigue and fracture research team to develop a series of original fatigue theoretical models after years of efforts, providing key theoretical support for solving the above problems.
Recently, the researcher Zhang Peng and the associate researcher Bai Xin of the team cooperated with the National Engineering Laboratory of high-speed train system integration of CRRC Changchun rail car Co., Ltd.
to combine these original theoretical models with traditional theories for key component materials such as high-speed train bogies, and jointly developed the “fatigue analysis platform for common materials and welded structures of rail cars”, and completed all software debugging and acceptance.
The function of the platform meets the development needs of domestic high-speed train materials and welding structures, and is supported and recognized by CRRC Changke.
The team’s doctors Liu Rui, Wang Bin, associate researchers Zhang Zhenjun, Pang Jianchao and researcher Zhang Peng proposed a series of fatigue performance prediction and optimization theoretical models for low cycle fatigue life, fatigue strength and fatigue crack growth rate.
As a key theory to solve the problem that material fatigue performance mostly depends on “trial and error”, they were integrated into fatigue analysis software for the first time.
In terms of low cycle fatigue life, a prediction model of low cycle fatigue life based on hysteresis energy parameters is proposed, and the relationship between low cycle fatigue life of metal materials and micro damage mechanism is established.
Based on important parameters such as tensile static toughness and work hardening rate, the quantitative prediction of low cycle fatigue life is realized; In terms of fatigue strength, based on a large number of fatigue strength experimental results and previous data, a high cycle fatigue strength prediction model is proposed.
By introducing parameters such as alloy composition, microstructure and macro defects, the quantitative prediction and optimization of high cycle fatigue strength of metal materials are realized; In terms of fatigue crack growth rate, based on a large number of fatigue crack growth experiments and theoretical analysis of fracture mechanics, a prediction model of fatigue crack growth rate is proposed by introducing strength factors and toughness factors on the basis of the classical Paris formula, and the fatigue crack growth life is rapidly predicted and improved through the graphic method of equal fatigue crack growth rate.
In addition, the platform also integrates the relationship between strength and hardness, fracture toughness strength relationship, fracture toughness size effect model, equivalent fatigue life method (EQ) and Monte Carlo probabilistic fatigue strength method (MS) proposed by team members, providing new theories and methods for simplifying relevant performance testing and analysis.
These original research achievements have published more than 10 papers in actamaterialia, physicalreviewb, Journal of Materials Science & technology, materials science and Engineering: A, International Journal of fate and other journals, and applied for more than 10 authorized patents.
The research work is supported by the key projects of the National Natural Science Foundation of China, the automobile joint fund project, the general project, the national key R & D plan and the strategic leading science and technology project of the Chinese Academy of Sciences.
On the basis of the innovation of fatigue theory, Bai Xin, an associate researcher of the team, integrated the methods of commercial fatigue life analysis software, established a database of structure and performance based on domestic materials and welded joints, solved the differences in methods and parameters of average stress correction, structural stress correction and fatigue strength correction between commercial fatigue analysis software and domestic materials / welded joints, and integrated the corresponding classical correction theory, The component life prediction module of the software platform is established.
Aiming at the problems that the evaluation standards of welded joints and base materials used in the design of high-speed trains in China involve many, complex use and high learning costs, the common standards of welded joints and base materials of high-speed trains such as iso12107, eurocode3, eurocode9, bs7608, BS7910, dvs1608, dvs1612, IIW, pren17149 and FKM are integrated in the algorithm, so that designers can directly call the program modules of relevant standards for calculation, It simplifies the evaluation process of welded joints and base metal of high-speed trains and provides convenience for reliability design of key components of high-speed trains.
The platform has been installed and operated in CRRC Changchun rail car Co., Ltd.
at present.
The two sides will continue to conduct in-depth and comprehensive cooperation to further improve the software platform in view of the shortcomings of traditional theories, so as to better serve the service performance evaluation of key components of high-speed trains.
Through development, the software platform is expected to be further popularized and applied to key components in important fields such as aviation, shipbuilding and machinery manufacturing.
Main modules and features of fatigue analysis platform for common materials and welded structures of rail cars source: warm tips from Institute of metals, Chinese Academy of Sciences: Recently, wechat official account information flow has been revised.
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