Research On Impedance And Vibration Transmission Characteristics Of Corrugated Diaphragm Couplings

Diaphragm couplings are commonly used components in ship shafting.According to the different types of diaphragm surfaces,diaphragm couplings can be divided into many types.This article takes corrugated diaphragm couplings(MCD)as the object,simplifies the modeling of the elastic components of the main components of MCD,analyzes the influence of diaphragm structural parameters on the axial stiffness,modal characteristics,and vibration transmission characteristics of the diaphragm components,and analyzes the strength and safety of MCD The influence of intermediate shaft length and output end elastic components on the vibration transmission of MCD was analyzed,and an experimental platform was built to verify the modal characteristics of the elastic components and the vibration transmission characteristics of MCD.The main research content of this article is as follows:Based on the simplified thin layer element method,a simplified modeling of MCD elastic components was carried out.By analyzing the static stiffness of the elastic components,the structural parameters of the bolt joint surface were determined,and the simulated modal natural frequencies were compared with the experimental results.It was found that the error between the modal natural frequencies calculated by the finite element method and the experimental natural frequencies was within 10%.A grid independence analysis was conducted on MCD,and a 25 mm grid was ultimately determined for calculation.Static stiffness and modal analysis were conducted on elastic components with different structural parameters,and it was found that the static stiffness of the elastic component increases with the decrease of the outer diameter of the corrugated membrane,the increase of membrane thickness,the increase of membrane ripple cycles,and the increase of membrane ripple amplitude.Changing the outer diameter,thickness,and number of corrugated periods of the corrugated membrane has a significant impact on the natural frequencies of the elastic component above the sixth order.The amplitude of the corrugated membrane has a significant impact on the natural frequencies of the elastic component above the twentieth order,with the outer diameter of the membrane having the greatest impact on the natural frequencies.As the outer diameter of the diaphragm increases and the thickness of the diaphragm increases,the axial vibration level drop of the elastic component will gradually increase,while the radial vibration level drop will gradually decrease.As the number of corrugated periods of the diaphragm increases,the axial and radial vibration level drop of the elastic component will gradually increase.The axial and radial vibration level drop of the elastic component will first increase and then decrease as the amplitude of the corrugated membrane ripple increases.As the outer diameter of the membrane decreases,the thickness increases,and the amplitude of the membrane ripple increases,the axial and radial origin impedance levels of the elastic component will gradually increase.As the number of corrugated periods of the diaphragm increases,the axial origin impedance of the elastic component gradually increases,while the radial origin impedance gradually decreases.The outer diameter of the diaphragm has the greatest impact on the origin impedance level of the elastic component.Changing the length of the intermediate connecting shaft of the MCD has little effect on the radial origin impedance of the MCD,while changing the amplitude amplitude and number of cycles of the output elastic component diaphragm ripple has a greater impact on the radial origin impedance and level drop.As the number of diaphragm ripple cycles or the amplitude of the diaphragm amplitude increases,the radial average level drop of the MCD in the entire frequency band will gradually increase.We have built a MCD and elastic component testing platform,and the natural frequency simulation and testing errors of the elastic component are less than 5%.The modal formation matches well.In the total frequency band,the average origin impedance level and vibration level drop errors obtained from simulation and testing are both within 1d B.The average origin impedance level error of MCD machine simulation and testing is 0.7d B,and the average vibration level drop error is 1.0d B.In summary,this article has studied the vibration related characteristics of MCD and elastic components,and the research results can provide some reference for the structural design of MCD.