Multi-Objective Optimization for Enhancing Rail E-Clip Design in Fastening Systems

CSME 2025/08
Volume 46 No.4 : 363-376

Multi-Objective Optimization for Enhancing Rail E-Clip Design in Fastening Systems

Cheng-Kang Lee ^a, Yung-Chang Cheng ^b, Chih-Chiang Lin ^c, Cheng-Hao Huang ^d, Chen-Ming Kuo ^e and Ming-Yi Hsu ^f
^aProfessor, Department of Industrial Engineering and Management, Cheng Shiu University, Kaohsiung, Taiwan 833301, ROC.
^bProfessor, Department of Mechatronics Engineering, National Kaohsiung University of Science and Technology, Kaohsiung, Taiwan 824005, ROC.
^cAssistant Professor, Department of Civil Engineering, National Kaohsiung University of Science and Technology, Kaohsiung, Taiwan 807618, ROC.
^dAssistant Professor, Department of Vehicle Engineering, National Taipei University of Technology, Taipei, Taiwan 10608, ROC.
^eProfessor, Department of Civil Engineering, National Cheng Kung University, Tainan, Taiwan 701401, ROC.
^fGraduated Student, Department of Mechatronic Engineering, National Kaohsiung University of Science and Technology, Kaohsiung, Taiwan 824005, ROC.

Abstract: This study focuses on improving the fatigue safety and structural strength of a rail e-clip in fastening systems under impact, fatigue, and static loads by employing advanced optimization techniques. Using the EN 13146-1, EN 13146-2, and EN 13146-3 testing standards, von Mises stress in the rail e-clip is evaluated via simulations performed in ANSYS/Workbench. Additionally, EN 13146-4 testing simulations assess the fatigue safety factor. The multi-objective optimization problem is solved using an integrated approach combining the uniform design of experiments methodology, Kriging interpolation, entropy weighting method, grey relational analysis, and the genetic algorithm, leading to an optimal design. The improved design shows reductions in von Mises stress of 9.9%, 22.12%, and 28.6% for the EN 13146-1, EN 13146-2, and EN 13146-3 testing simulations, respectively, compared to the original model. Meanwhile, the EN 13146-4 testing simulation shows a 29.8% improvement in the fatigue safety factor, which rises to 6.18. Thus, the structural strength and fatigue performance of the rail e-clip are significantly improved. Finally, the impact of each design variable on the objective functions is determined using Sobol sensitivity analysis. According to the sensitivity results, the diameter of the rail clip has a significant impact on most objective functions.

Keywords: rail fastening system, rail e-clip, von Mises stress, fatigue safety factor, uniform design, Kriging interpolation, Sobol sensitivity analysis.

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