Research On Dynamic Characteristics Of High Speed Test Bench For Electric Vehicles

The high-speed measurement system has been widely employed for assessing the power transmission system of electric vehicles,yet the impact of vibration on its safety and stability cannot be overlooked.As an important piece of mechanical construction,the kinematic characteristics of the rotor system will influence directly the operating efficiency and safety of the rotating machinery.However,due to the presence of alternating forces,rotating machinery may experience imbalances and misalignment,which can result in vibrations of the entire machine.Aiming at vibration problems on high-speed testing platform,and the main work and findings are summarized as follows:(1)According to the theory of finite element optimization analysis,the response surface optimization method based on sensitivity screening was used to optimize the size parameters of the base structure and determine the geometric structure of the base.By comparing the vibration level drop of different structural bases,the advantages and disadvantages of different forms of structural bases in terms of mode,mass,and vibration reduction are analyzed;On this basis,a dynamic modeling of the test bench base was conducted,and the natural frequency of the test bench was simulated and analyzed using finite method.The response results of the test bench base were calculated using modal superposition method.The results showed that the honeycomb rib plate structure with the same structural size can better reduce the vibration of the test bench while ensuring the dynamic characteristics of the overall structure and achieving structural lightweight.(2)Based on rotor dynamics theory,finite element method is used for modal analysis,calculation of natural frequency,critical speed,and imbalance response.Based on the structure of the ZT-3 rotor vibration simulation test bench,modal analysis,Campbell plot analysis,and harmonic response analysis were conducted on the rotor part.The effects of imbalance and misalignment were considered,and the characteristics of the rotating component rotor system of the test bench were analyzed.The speed law and rotor characteristics with changes in speed were obtained when the rotor was operating with imbalance.(3)Conduct a comprehensive analysis of the test bench,based on the modal analysis results,determine the excitation force according to the dynamic balance level,and add it to the model for harmonic response analysis to obtain the vibration characteristics of the test bench for the dynamic balance G2.5 system under different rotational speed excitation forces.(4)Modal testing was conducted on the disc shaft rotor and an imbalance experimental platform was built for the rotor system.The experiment was conducted by changing the magnitude of the imbalance mass to measure the acceleration signals under different imbalance mass conditions.The corresponding spectrum was obtained through Fourier transform,and the experimental results qualitatively matched the finite element simulation results,verifying the correctness of the finite element analysis results.