| As one of the important sealing elements in the field of mechanical seals,S-shaped welded metal bellows were widely used in the mechanical seals in the fields of hydraulic and pneumatic technology in petrochemical,chemical,aerospace and other industries.However,when the welded metal bellows resonates with the system,it would cause the bellows to leak,reduce its life,and even lead to serious failures of the entire system,seriously threatening the safety of equipment,personnel,and property.Vibration modal analysis and test analysis can predict the natural vibration frequency and basic vibration form of the bellows to prevent the resonance of the bellows during use,thereby avoiding serious consequences.This article was mainly for the four types of S-type weld metal DN63.5-12 wave single layer,DN55-12 wave double layer,DN55-8 wave double layer and DN40-12 wave double layer provided by Xinjiang Wusu North New Technology Co.,Ltd.Bellows for vibration characteristics analysis.First of all,finite element analysis was carried out on the S-shaped welded metal bellows.During the establishment of the analysis model,certain assumptions and simplifications were made.Through the comparative analysis of the two modeling methods,the feasibility of integral modeling was verified.Through comparative analysis of grids with different scales,it is proved that relatively stable vibration frequency and mode can be obtained when the grid scale is less than or equal to 0.5.Through the analysis of the modal and radial response frequency,the basic vibration mode,natural frequency value and response frequency of the welded metal bellows under ideal boundary conditions were obtained.Then build two test platforms for swing excitation and rotation excitation,and design simple tooling fixtures.The S-type welded metal bellows were tested under two excitation modes: swing excitation and rotation excitation,and the vibration signal was tested and extracted using an acceleration sensor and a non-contact laser vibration meter.The first six-order frequency response curve with one end fixed and the other end free is obtained,and its frequency response curve within 1000 Hz at actual working speed.By analyzing the response curves,the actual vibration frequency of the welded metal bellows is determined,and the vibration characteristics of the welded metal bellows were obtained.Finally,through comprehensive comparison and analysis of test results and simulation analysis results,the source of error was analyzed.In particular,the horizontal and vertical comparison analysis of the three most widely used double-layer corrugated pipes was carried out.Under the same boundary conditions,the double-layer welded metal corrugated pipes obtained At the same time,when the wave number is high,the frequency value is small,and when the wave number is low,the frequency value is large;but when the wave number is the same,the frequency value of the inner and outer diameters is large,and the frequency value of the small inner and outer diameters is also small.At the same time,the reliability of the simulation analysis results and the relative stability of the contactless test method were verified.The analysis of the vibration characteristics of the S-shaped welded metal bellows shows that the first-order frequency of both the simulation results and the test results is much larger than the theoretical working frequency of the actual working conditions of the bellows.Therefore,the bellows does not consider the moving ring There is no resonance phenomenon under the condition of compound vibration of static ring and other components.It provides a reference for the design,manufacture and application of welded metal bellows seals. |
