Research on dangerous bolts rapid identification method for high-speed train’s heavy suspension equipment based on design stage

Purpose The underframe connection configurations of heavy-duty suspended equipment in high-speed train have diverse forms and complex loading positions. To rapidly confirm the load-bearing conditions of dangerous bolts between the EMU (Electric Multiple Unit) heavy-duty suspension equipment and the underframe during the design phase, improve the efficiency of bolt group load analysis, and guide designers in quick bolt-type selection, this paper proposes an executable method for fast confirmation of dangerous bolts in heavy-duty suspension equipment. Design/methodology/approach Based on the rigid body mechanics method in the VDI (Verein Deutscher Ingenieure) 2230–2 standard, the working loads of connection bolts for heavy-duty suspension equipment under high-speed train were studied. A rapid confirmation program for dangerous bolts was developed using Python language and the PyCharm development platform. The confirmation of dangerous bolts was conducted respectively with connection bolts of top-suspended and bottom-supported equipment as carriers. Sensitivity analysis was performed to verify the accuracy of the research findings. Findings A confirmation method for dangerous bolts under various connection configurations that satisfies engineering applications was obtained. A highly efficient and convenient application platform for the method was developed. An executable operational process for dangerous bolt confirmation was provided, and the accuracy of calculation results was verified. The research achievements offer technical references for confirming dangerous bolts in complex engineering products during the design phase. Originality/value Based on the fundamental theory of the rigid body mechanics method, the study on the load distribution law of bolt groups was completed, and the determination criteria for dangerous bolts were clarified. By combining the typical top-suspended and bottom-supported configurations of high-speed train, the influence of external load application points on the load-bearing characteristics of bolts was analyzed, forming calculation methods under different connection modes and establishing quantitative classification criteria based on different danger levels. Engineering application results demonstrate that this method can rapidly complete dangerous bolt confirmation, significantly shorten the bolt-type selection cycle, eliminate simulation modeling work, and provide methodological guidance for confirming dangerous bolts and optimizing parameters during product design stages.