PSI - Issue 22

B.R. Miao et al. / Procedia Structural Integrity 22 (2019) 102–109 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

108

7

Table 2. Some optimization comparison results of the carbody structure

parameters

Unite Initial value Optimization value Relative error

Carbody Mass

kg Hz

8070.53

7531.78

-6.68% -3.12% 0.09% 6.96%

First bending mode Von mises stress

19.25

18.65

Mpa

170.76

170.92

Maxium displacement mm

16.38

17.52

Table 3. Fatigue damage and life prediction in the carbody structure optimization

Fatigue damage Fatigue Life No optimization Optimization No optimization Optimization

Node

8999 9242 9001

9.81E-05 9.79E-05 9.77E-05 9.72E-05 9.69E-05 9.64E-05 9.62E-05 9.52E-05 9.50E-05 9.28E-05

2.14E-06 2.13E-06 2.12E-06 2.10E-06 2.07E-06 2.06E-06 2.04E-06 2.03E-06 2.02E-06 2.01E-06

1.02E+04 1.02E+04 1.02E+04 1.03E+04 1.03E+04 1.04E+04 1.04E+04 1.05E+04 1.05E+04 1.08E+04

4.68E+05 4.70E+05 4.72E+05 4.76E+05 4.84E+05 4.86E+05 4.90E+05 4.92E+05 4.95E+05 4.98E+05

37388 37676 37363 37617 31455 31212

8731

5. Conclusion Based on the multidisciplinary fatigue optimization design of the carbody structure, the carbody mass is reduced about 538.75kg.And the lightweight efficiency is about 6.68%. The first-order bending natural frequency of the carbody structure is 18.65Hz, which is 3.1% lower than the first-order vertical bending frequency of the initial carbody structure. It is higher than the recommended value of 14Hz of the first-order inherent bending frequency of the aluminum alloy carbody structure, which can satisfy the dynamic design requirements of the EMU train. The MDO fatigue optimization comparison calculation of the carbody structure under multi-load conditions before and after optimization was carried out. The results are shown that the anti-fatigue performance of the lightweight carbody structure can be improved used multidisciplinary fatigue optimization design method. Acknowledgements The authors give thanks to the National Natural Science Foundation of China (51775456, 51375405), the Research Project of State Key Laboratory of Traction Power (2019TPL_T03). References Sobieszczanski Sobieski J. 1989.Multidisciplinary optimization for engineering systems: Achievements and potential. Optimization: Methods and applications, possibilities and limitations. Berlin, Heidelberg. Hoogreef, M. F., D'Ippolito, R., Augustinus, R. 2015. A multidisciplinary design optimization advisory system for aircraft design. 5th CEAS Air and Space Conference Challenges in European Aerospace, Delft, Netherlands, paper # 41. Miao B., Zhang W. Zhang J. et al. 2009. Evaluation of Railway Vehicle Carbody Fatigue Life and Durability using Multi-disciplinary Analysis Method. Int. J. Vehicle Structures & Systems.1 (4), 85-92. Wennberg, D., Stichel, S. 2014. Multi-functional design of a composite high-speed train body structure. Structural and Multidisciplinary Optimization, 50(3), 475-488. Hirsch, J. 2011. Aluminum in innovative light-weight car design. Materials Transactions. 52(5), 818-824. Morteza, K., Imtiaz, G., Masoud, R. R., 2014. Design of lightweight magnesium carbody structure under crash and vibration constraints. Journal of Magnesium and Alloys. 2(2), 99-108.