Modalanalysis And Structural Optimization Of Vibro Ripper

As a new type of broken hammer,the Vibro Ripper is very different from the hydraulic broken hammer,which has the advantages of low working noise and high work efficiency.At present,the Vibro Ripper is still in research and trial stage.only China,South Korea,Spain and some European countries to develop the product,and some progress and scientific results have been made.Due to the poor working conditions,the Vibro Ripper will vibrate arising from the incentives outside,the eccentric block helical gear will have an impact in the meshing process,the shock pass through the shaft and bearing to the gear box,which cause the vibration.The vibration of Gear box can easily lead to wrong and the fatigue damage,reducing the life of gearbox.To carry out the study of the dynamic characteristics about the Vibro Ripper has become essential.In this paper,the SV-60 Vibro Ripper is taken as the research object,the finite element model is established according to the special structure and working conditions of the vibro ripper.And then the static characteristics analysis,theoretical analysis and motion simulation of the vibro ripper are carried out,compared with the experiment,the accuracy of the finite element model was confirmed.Then the modal analysis of the exciter is further carried out,according to the analysis results,the structure of the Vibro Ripper is optimized.The main work is as follows:Firstly,the three-dimensional model of the SV-60 Vibro Ripper was established by CATIA,according to the actual working conditions,the vibro ripper is simplified and introduced into ANSYS,the finite element model was established.The statics analysis,the theoretical analysis,the motion simulation and test are carried out.According to the statics analysis,the parts of the stress concentration of the exciter and the vulnerable parts are determined.Comparing the experimental results with the finite element analysis can further prove the accuracy of the finite element model of the Vibro Ripper.Secondly,the modal analysis of the Vibro Ripper is carried out,according to theresults of the modal analysis,the natural frequency and displacement of the exciter are determined.Then it is judged whether the natural frequency of the exciter and the frequency of the exciting force are close to or equal to determine whether the exciter reaches the resonance.According to the modal vibration mode,the first six modes of the exciter are mostly integral mode.Mainly swinging,twisting and rotating,which has great influence on the strength and rigidity of the structure of the exciter,and the service life of the Vibro Ripper is seriously affected,and sharpening the Wear of gear teeth Surface.Finally,according to the above calculation and analysis results,the connection between cutting tools-array and bucket teeth is optimized firstly.The maximum equivalent stress in the static analysis is used as the constraint variable,and the minimum deformation of the exciter is taken as the target variable to optimize the structure of the exciter box.The optimization results show that the stress at the connection between bucket teeth and cutting tools-array is obviously decreased,less than the allowable stress,and the structure improvement effect is obvious.And them the maximum deformation of the exciter box is reduced by 18% and the maximum equivalent stress is reduced by 22.96%,which improves the overall performance of the exciter box.The optimized exciter’s natural frequency can avoid the frequency of excitation force,and will not resonance with the structural change.