Vibration environment spectrum investigation of metro bogie frame end

Vibration fatigue failure of equipment at the bogie frame end occurs from time to time, mainly due to the lack of a suitable vibration environment spectrum during the design stage. The IEC standard spectrum does not match the actual vibration, so a more suitable spectrum for bogie frame end under current China's metro operating conditions is compiled through a large amount of acceleration samples. This paper first determines the frequency range of the spectrum. After normal distribution test, the improved normal tolerance upper limit (NTL) method is then adopted to obtain the upper limit of the acceleration spectral density (ASD) of the samples. Finally, the spectrum is converted to one-third octave band form for fatigue calculation and bench test. The engineering case shows that compared with the IEC standard spectrum the improved NTL method spectrum ensure conservative evaluation results while retaining reasonable safety margins.