Design On Two-Stage Vibration Isolation Test Bed With Multiple Subsystems And Identification Of Inertia Properties

The powerpack on Diesel Multiple-Unit (DMU) is a typical two-stage vibration isolation with multiple subsystems, its improper isolation design will directly affect the performance of the components, while the riding comfort of the passenger car will be reduced greatly. The test bed is an important means to study the mechanism and performance of the vibration isolation system design. The performance parameters and influence rules of vibration isolation system could be obtained using the test bed, in order to provide a reference for studying the mechanism and characteristics of the vibration isolation system.This paper designed a two-stage vibration isolation test bed with multiple subsystems, and a visual inertial parameters identification procedure was developed based on experimental modal analysis method.Taking the DMU power pack as prototype, a two-stage vibration isolation test bed with multiple subsystems was designed, which considered many influence factors including the change of centroid of main system and subsystem, the installation position of vibration isolator, the mass ratio of public framework and subsystem, etc. Based on the design parameters, the three dimensional model of the components were be built up, and virtual assembly ensured that there is no interference between the structural components of the assembly design. The finite element model of the mounting bracket was built up on the basis of ANSYS software, and the static and dynamic analysis results verified that the mounting bracket could meet the requirements of strength and structural design. At the same time combining the analyzed exciting force results to make modal match of mounting bracket for engine, in order to avoid the impact on the isolation experiment station research. Finally experiments were carried out and results showed obvious isolation effect on the test bed, which can conduct relevant experimental vibration isolation researches.Then the visual inertia parameter identification program based on modal analysis method was developed. Simulation results showed that the maximum identification error is 0.63%, and experiment results showed that the maximum identification error is 3.9%, so the program could be used to identify inertial parameters. Identification accuracy of inertial parameters was analyzed from many aspects based on the developed program, including the error of exciting force position, the deviation of exciting force direction, the error of response position, the error of acceleration response, the parameters of vibration isolator, etc. and the results could provide reference for experimental test.In summary, the present work will provide not only a experimental platform for the two-stage vibration isolation system design with multiple subsystems, but also a reference for similar constructions of experimental platform, while offering a method of obtaining inertial parameters of complex structure.