Issue 48

B. Chen et alii, Frattura ed Integrità Strutturale, 48 (2019) 385-399; DOI: 10.3221/IGF-ESIS.48.37 398 standard requirements, and the bogie frame needs to be redesigned and optimized. According to Eqn. (12), the reliability of bogie frame under the two evaluation standard is 1 and 0, respectively. It shows that the fatigue limit diagram without considering safety factor can also be used to evaluate the bogie frame, and the traditional method has excessive safety factor, which is too conservative in design. C ONCLUSIONS his paper presents a fatigue strength analysis method by considering uncertainty of design parameters based on GSFLD and reliability theory, and the practicability of the method is verified by employing NGSFLD for bogie frame. The proposed method solves the problem of conservatism in traditional fatigue strength analysis from two aspects: On the one hand, considering the uncertainty of design parameters, a parameterized model is established, and the fluctuation of control points under the uncertainty parameters is calculated. Compared with deterministic analysis, it can reflect the discreteness of analysis results caused by uncertainties such as design, manufacturing and working conditions. On the other hand, the fatigue limit diagram without considering safety factor is established. Compared with the fatigue limit diagram provided in ORE B12/RP17 standard, the excessive redundancy and conservative of the design scheme are solved. The fatigue strength reliability analysis results of the two methods are 1 and 0, respectively. It shows that the traditional method is too conservative to evaluate the design scheme, which results in that the reliability of the original qualified design is 0 due to the high safety factor of the evaluation standard, which does not meet the requirements. It not only wastes resources, but also is not conducive to the lightweight design of railway vehicles. In general, in order to ensure the safety of structural design and achieve the purpose of lightweight design, the parameter uncertainty considered in the design stage is more consistent with the actual needs of the project. A CKNOWLEDGMENTS his research is supported by the National Natural Science Foundation of China under Contract No. 51875073, the Education Project of Liaoning Provincial Department under Contract No. JDL2017022, Liaoning Provincial Natural Science Foundation of China under Contract No. 20170540129. R EFERENCES [1] Claus, H. and Schiehlen, W. (2007). Modeling and simulation of railway bogie structural vibrations, Veh. Syst. Dyn., 29(1), pp. 538-552. DOI: 10.1080 /00423119808969585 . [2] Stichel, S. and Knothe, K. (2007). Fatigue life prediction for an s-train bogie, Veh. Syst. Dyn., 29(1), pp. 390-403. DOI: 10.1080 /00423119808969573 . [3] Ren, Z.S. and Xie, J.L. (2008). Influence on axle load to the service life of the crossbar set of railway freight car with equivalent load, J. Mech. Eng., 44(3), pp. 16-21. DOI: 10.3321/j.issn:0577-6686.2008.03.003. [4] Zhu, N., Sun, S.G., Li, Q. and Zou, H. (2016). Theoretical research and experimental validation of elastic dynamic load spectra on bogie frame of high-speed train, Chin. J. Mech. Eng., 29(3), pp. 498-506. DOI: 10.3901/CJME.2016.0308.027. [5] Park, B.H. and Lee, K.Y. (2006). Bogie frame design in consideration of fatigue strength and weight reduction, Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, 220(3), pp. 201–206. DOI:10.1243/09544097f01405. [6] Han, J.W., Kim, J.D. and Song, S.Y. (2013). Fatigue strength evaluation of a bogie frame for urban maglev train with fatigue test on full-scale test rig, Eng. Fail. Anal., 31, pp. 412–420. DOI:10.1016/j.engfailanal.2013.01.009. [7] Hwa, P.B., Po, K.N., Seok, K.J. and Yong, L.K. (2006). Optimum design of tilting bogie frame in consideration of fatigue strength and weight, Veh. Syst. Dyn., 44(12), pp. 887–901. DOI:10.1080/ 00423110600737106. [8] Seo, J.W., Hur, H.M., Jun, H.K., Kwon, S.J. and Lee, D.H. (2017). Fatigue Design Evaluation of Railway Bogie with Full-Scale Fatigue Test, Adv. Mater. Sci. Eng., 2017, pp. 1–11. DOI:10.1155/2017/5656497. [9] Li, F.S., Wu, P.B., Zeng, J. and Wang, J.B. (2014). Study on the differences between the three common fatigue strength, J. Mech. Eng., 50(14), pp. 170-176. DOI: 10.3901/JME.2014.14.170. T T