Dynamic Stiffness Characteristics Analysis of Bogie Suspension for Rail Vehicle Based on Big Data-Driven Bench Test

The vehicle test big data has important significance for the study of vehicle performance and characteristics. Aiming at the test of the dynamic stiffness characteristics of a bogie suspension system of rail vehicles, a simplified rigid-flexible hybrid model of the bogie is established, and the force condition of the bogie suspension system is analyzed. Based on this simplified model, a mathematical model of the dynamic stiffness of the primary suspension, secondary suspension, and integrated suspension is established. In addition, a method for testing the three-way dynamic stiffness of a bogie suspension system in a complete, assembled state is proposed, and a dynamic stiffness test model of the bogie primary suspension, secondary suspension, and comprehensive suspension is established. Dynamic stiffness tests of the primary suspension, secondary suspension, and integrated suspension were carried out, and according to the big data analysis of the bench test, the dynamic stiffness curve of each suspension in the frequency of 0.5-5 Hz is obtained. The test results show that the dynamic stiffness of the suspension of the bogies varies nonlinearly with the change in frequency. The dynamic stiffness values of the suspensions at different frequencies vary greatly. As a result, the vehicle's operating characteristics cannot be evaluated based on the suspension static stiffness or the suspension stiffness at a single frequency, indicating the necessity of the suspension dynamic stiffness test after the bogie is assembled.