| With the development of modern rail transit industry,the research and development of new permanent magnet direct drive locomotives has been put on the agenda.The safety and reliability of new process and new technology are very important in locomotive application,the typical one is the application of the drive mechanism represented by the laminated membrane coupling in the permanent magnet direct drive locomotive.It is necessary to study the vibration and fatigue characteristics of the coupling because of its special installation position and severe load conditions in service.In this thesis,according to the rail transit industry standard,the structural sweep vibration test,functional random vibration test and long life accelerated fatigue test of the laminated membrane coupling of permanent magnet direct drive locomotive are designed.Based on the test results,the inherent vibration characteristics,transmission performance and fatigue reliability of the laminated membrane coupling are studied.In the sweep test of laminated membrane coupling,the transverse tests with lateral preset displacements of 0 mm,±6 mm,±12 mm and the vertical tests with lateral preset displacements of 0 mm,±10 mm,±15 mm are designed,then,the modal parameters of the sweep test results are identified.The results show that the preset displacement has a significant effect on the transverse first-order modal frequency and damping,but a small effect on the vertical modal frequency and a large effect on the vertical modal damping.The contact stiffness factor is calculated by G-W contact model and ANSYS contact algorithm,and the contact modal simulation model of laminated membrane coupling is established.Under the condition of large deformation,the prestressing modal of the laminated membrane coupling with preset displacement is calculated.The validity of the simulation method is verified by comparison with the experiment results.In order to study the vibration transfer performance of the laminated membrane coupling,the stiffness calculation model of the laminated component is firstly established,and the influence of the laminated layer number,bolt preload and combined friction factor on the stiffness nonlinearity is analyzed.Combining the stiffness of laminated components with different number of layers and the simplified single degree of freedom and double degree of freedom vibration systems,theoretical research is carried out on two kinds of test conditions,namely,transverse 2 and transverse 3,and the effects of mass,stiffness and damping on the evaluation indexes of vibration level drop and insertion loss are analyzed.Furthermore,the measured frequency response function,acceleration level drop and insertion loss in the functional vibration test are calculated,and compared with the theoretical results,it is proved that the theoretical analysis of vibration isolation is an effective method in the preliminary design of coupling.Meanwhile,the stress time history and stress power spectrum of the main measuring points of the laminated membrane coupling are obtained through the long-life vibration fatigue test,combined with the fatigue S-N curve modified by FKM,the average stress is modified by Goodman curve,and the damage is calculated in time domain according to the damage accumulation theory,and based on the stress distribution estimated by Dirlik,Lananne and Narrow Band formulations,the frequency damage is calculated.Finally,the fatigue simulation model of the laminated membrane coupling is established,the results of stress harmonic response analysis of each position of the coupling are obtained by the modal superposition method,and the stress power spectrum is obtained by superimposing the harmonious response results of the standard excitation spectrum.Then,Dirlik probability formula is used for damage prediction,and the accuracy of the simulation method is verified by comparing with the experimental damage results. |
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