Analysis Of Dynamic Characteristics And Optimization Design Of Rotor Of High Speed Steel Wire Braiding Machine

As a key production equipment for high-pressure rubber hoses required in agriculture,industry,construction,aerospace and other fields,high-speed steel wire braiding machines play an important role in China's industrial field.This project aims to study the dynamic characteristics of a certain type of wire braided machine rotor and solve the problem of fatigue fracture at its key position.In this paper,the finite element model of the rotor is subjected to modal analysis and transient dynamics analysis through the ANSYS Workbench software platform,and the fatigue life assessment is carried out.Then the multi-objective optimization design is carried out for the simulation results.First,based on the finite element analysis(FEA)technique,a numerical model of the roter is established,and boundary conditions are met to meet the actual working conditions.In order to explore the problems of vibration and noise during the operation of the machine,the Modal module in Workbench is used to analyze constraint mode to determine the dynamic characteristics of the rotor,and the influence of the pre-stress on the natural frequency is analyzed.It can be seen from the analysis that the natural frequency of the rotor is significantly larger than the rotational frequency,so the structure does not resonate.Then the ANSYS Workbench software was used to analyze the transient dynamics of the main shaft,the polished rod positioning block bolt and the upper fork in the rotor,and the stress spectrum of the rotor was obtained.The nCode Designlife module is used to evaluate the fatigue life of the rotor based on the linear fatigue cumulative damage criterion and the resulting stress spectrum.The results show that the rotor will suffer fatigue damage after being subjected to the corresponding times of alternating loads.Therefore,in the above key areas,stress concentration and fatigue damage on the structure should be paid attention to.In view of the above problems,this paper optimizes the design of the braided rotor from the perspective of structure and material.For the main shaft and polished rod positioning block bolts,to reduce the key position stress value as the optimization target,combined with the response surface method for multi-objective optimization design,and use MOGA(multiobjective genetic algorithm)algorithm to select the optimal design point.For the upper fork,the high-strength 7075 aluminum alloy is used instead of the raw 2A12-T651 aluminum alloy,and the structure is innovatively optimized.Through analysis and comparison,the above scheme can effectively reduce the maximum stress value of the upper fork.The maximum stress variation width of the main shaft is 16.9% lower than that before optimization.The maximum stress variation width of the polished rod positioning block is reduced by 8.1% compared with that before optimization.The maximum stress variation width of the upper shift fork is reduced by 40.3% compared with that before optimization.The optimization results show that the implementation of the new scheme can reduce the stress concentration of key parts,better meet the requirements of optimized design,prolong the working life of the rotor structure,and save the maintenance cost in the later stage.