Grinding Exciting Force Simulation And Vibratory Fatigue Analysis Of Cement Vertical Mill

Vertical mill is a kind of grinding equipment which has a series of function such as fine crushing, fine crushing, grinding, powder selecting, conveying.And vertical mill is widely used in cement, chemical engineering, metallurgy and other fields. One Cement Plant improved a type of cement vertical mill. After improving, the serious vibration of vertical mill bracing structure frequently cause damage to anchor bolt and bracing structure. Faced with above problems, this paper employs a method of combination of simulation and experiment be applied to proceed structural strength analysis and Random Vibration Analysis on cement vertical mill, and find out the damage reason of anchor bolt and bracing structure.First the stress and vibration test is implemented to the cement vertical mill which is in normal working condition.stress value of anchor bolt and acceleration signal of bearing block are got through the test. Establishing model of vertical mill system by SolidWorks,and using the HyperMesh to mesh the geometric model of vertical mill system. The finite element statics analysis has been carried out on vertical mill under two boundary situations by Workbench. By contrasting the displacement and stress nephogram under the two boundary situations and result of the stress tests, the paper finds out the major cause of anchor bolt damage is that side of vertical mill foundation lacks support, so the anchor bolt needs to bear bending moment which is under tensional stress in the design. As well as vertical mill has serious vibration, so the anchor bolt subjects to variable loading, at last leading to fatigue failure. This paper also obtains fatigue life prediction of anchor bolt based on result of the finite element statics analysis by Goodman theorem.Cement clinker model has been established by the discrete element software of PFC3 D. Then this paper simulates uniaxial compression testing of cement clinker model,and constantly adjusts micro parameters until physical properties of the cement clinker model and the real one is similar. The numerical simulationthe process of cement grog pulverization is investigated, and exciting force of process of cement grog pulverization is acquired. Kinetic equation is listed of vertical mill swing-arm system based on machinery system dynamics. Through solving the equations by MATLAB, this paper gets acceleration time curve of grinder roll, and then estimates the power spectral density by periodogram. After comparing the power spectral density of simulation results and vibration test results, accuracy of the simulation has been confirmed. This paper alsomakes a modal analysis of vertical mill and the first six natural frequency and mode of vibration obtained via the modal analysis. Random vibration analysis is proceeded based on the modal analysis, and the power spectral density which was already simulated is motivation of the random vibration analysis, and stress nephograms at 1σ, 2σ, 3σprobability distribution were obtained. At last this paper estimats vibration fatigue lifetime of Support Structure of vertical mill through Palmgren-Miner linear cumulative damage theory of fatigue and Steinberg three interval method.This paper firstly simulates exciting force of vertical mill through the discrete element and vibratory fatigue of vertical mill. At last weak spots of vertical mill have been found out, vibration fatigue lifetime is estimated,and the results of this paper can be used as reference in vertical mill design.