Fatigue Analysis Of Mill Transmission System Based On Model Updating

The mill is the key equipment in the beneficiation process.Its working environment is harsh,and its structure and loading conditions are more complicated.As a power transmission structure,the transmission system is prone to fatigue damage and the mill cannot work normally,resulting in huge economic losses.Among them,the transmission shaft is the power transmission part of the transmission system,which is more susceptible to alternating load during work and the earliest fatigue damage occurs.Therefore,it is very important to study the fatigue characteristics of the transmission shaft.At present,most of the analysis of fatigue characteristics is based on the analysis of static model,which does not reflect the true working state of the components,which leads to inaccurate fatigue analysis results.In this paper,starting from the finite element model of the mill,the layered finite element model updating and confirmation technology is used,and the finite element model is calibrated using the experimental test dynamic response signal at the key position to realize the fatigue analysis of the mechanical transmission system.Considering the large size and complex structure of the mill,the feasibility of directly studying its transmission system,this paper carried out the following aspects of research:(1)Based on the theory of similar design,a similar test-bed of mill transmission system is designed and built.On this basis,the relevant modal test is designed.Based on the modal data,the finite element model updating idea of layered is used and the response surface method is used to update the finite element model of the transmission system.The error shows that the updating of the transmission system by this method is effective.(2)Considering that the model updating method based on the modal parameters does not reflect the dynamic response characteristics comprehensively,the model updating method based on the dynamic response is adopted on the basis of the above updated model,and the strain test of the transmission system in the running state is designed and implemented,and the integrated transmission system overall model is instantaneous based on the dynamic strain test data The validity of this method is verified by comparing the stress simulation results with the test results.(3)Taking the fatigue load spectrum of the transmission shaft obtained by multibody dynamics analysis,the SN curve of the transmission shaft and the finite element analysis results under the excitation of the unit load of the transmission shaft as input,complete the fatigue life analysis of the transmission shaft based on the linear damage theory to obtain,the fatigue analysis results of transmission shaft are obtained,and the dangerous parts of transmission shaft fatigue life are found,the feasibility of the method of fatigue analysis of the transmission system based on model modification was verified.The results show that the updated stress model of the mechanical transmission system has high accuracy,and the transmission shaft has sufficient fatigue life to work safely.