Operational transfer path analysis (OTPA) is an advanced vibration and noise transfer path identification and contribution evaluation method. However, the application of OTPA to rail transit vehicles considers only the excitation amplitude and ignores the influence of the excitation phase. This study considers the influence of the excitation amplitude and phase, and analyzes the contribution of the secondary suspension path to the floor vibration when the metro vehicle runs at 60 km/h, using an analysis based on the OTPA method. The results show that the vertical direction of the anti-rolling torsion bar area provides the maximum contribution to the floor vibration, with a contribution of 22.1%, followed by the longitudinal vibration of the air spring area, with a contribution of 17.1%. Based on the contribution analysis, a transfer path optimization scheme is proposed, which may provide a reference for the optimization of the transfer path of metro vehicles in the future.

Noise control is one of key issues to improve the ride comfort of metro trains. To find out the excitation source and its transfer path is an important prerequisite for noise control. The sound source identification results found that the significant noise source in metro trains is the structural-borne sound radiated by floor vibration. Based on the OTPA method, this study presents a method considering the amplitude and phase of the excitation to analyze the contribution of the secondary suspension path to the floor vibration. The results show that the energy of the passenger room noise mainly concentrates on the frequency range of 300~800Hz, caused by floor vibration; in the frequency range of 300~800Hz, the vertical direction of the anti-rolling torsion bar area provides the maximum contribution to the floor vibration, followed by the longitudinal direction of the air spring area. On the basis of contribution analysis, a transfer path optimization scheme is proposed, which may provide reference for future metro trains noise control.