A study on the effect of inerters in the motor elastic suspension on the stability of bogies in high-speed trains

Inerters are widely used in structural vibration systems, but there is little research on their use in the elastic-suspension of motors in high-speed train bogies. The type of the motor suspension significantly influences its vibration characteristics. To fill this gap, this paper proposes the use of the frequency-variable characteristics of the inertia spring damping (ISD) structure. The motor elastic-suspension bogie dynamic model with the inerter was established, and the effect of the motor suspension parameters on the stability of the bogie system was studied. Finally, the inertia-suspension parameters were optimized by the Non-dominated Sorting Genetic Algorithm-Ⅱ (NSGA-Ⅱ) multi-objective optimization algorithm. The results showed that the ISD structure has frequency-varying characteristics, and the maximum equivalent stiffness and damping exist in the low frequency range (approximately 10 Hz). As the equivalent conicity increases, the optimal lateral frequency and damping ratio of the motor increase, which makes the inerter suspension bogie to meet this characteristic. The optimized motor suspension parameters showed that the linear critical speeds of the bogie with inerter suspension are improved, and the stability of the bogie is higher within the equivalent conicity of 0.1-0.4. This study can provide a reference for the stability design of the bogie structure in future.