Research On Finite Element Calculation Method Of Rolling Resistance Of Belt Conveyor

Belt conveyor is the most important continuous conveying equipment for bulk materials.It is widely used in mines,ports,grain,chemical fields,etc.It has the advantages of economy,high efficiency,reliability and safety compared with automobile and railway transportation.At present,further energy saving research on belt conveyor has become a hot spot in belt conveyor research.The indentation rolling resistance accounts for about 60%of the total running resistance of the belt conveyor.Therefore,the research on the calculation method of the indentation rolling resistance plays a key role in energy saving of the belt conveyor.The research progress of the indentation rolling resistance of belt conveyor and the test method of viscoelastic material characteristics were analyzed.The finite element method of the indentation rolling resistance was studied by learning from the doctoral thesis of Munzenberger.In the finite element analysis model,the elastic matrix of viscoelastic material should be used to set the material properties for the cover of conveyor belt.Therefore,the elastic matrix of viscoelastic material was derived:the numerical integration was derived according to the constitutive equation of viscoelastic material,and the constitutive relationship of viscoelastic material in the finite element analysis model was determined.Then,the elastic matrix of viscoelastic material expressed by shear modulus and bulk modulus was obtained by combining stress tensor and strain tensor and generalized Hooke's law.The shear modulus and bulk modulus were obtained by studying the viscoelastic properties of the conveyor belt cover material.According to the DMA test results of the conveyor belt cover material and the principle of time-temperature equivalence,the master curve of the rubber cover was obtained.The relationship between the modulus of the conveyor belt cover material and the frequency was established through the generalized Maxwell model.The model parameters were solved based on the genetic algorithm and the master curve data,and the relaxation modulus function of the generalized Maxwell model was determined.According to the relationship between shear modulus,bulk modulus and relaxation modulus,the shear modulus function and the bulk modulus function were obtained.The model of single steel code indentation rolling resistance was established by using the finite element software Abaqus.The viscoelastic parameters of the cover material of conveyor belt were calculated by the elastic matrix,which was input into the software to set the viscoelastic properties of the material.The calculation and input of viscosity parameters were related to the calculation and application of node force.The calculation program of node force was written by Matlab,and the Abaqus script file was written by Python.The script file was run to apply the corresponding node force on each node of the conveyor belt cover model.Based on the moment summation method and energy method,the indentation rolling resistance was calculated.And the repeatability of the steel cord of the conveyor belt was verified.At the same time,the influence of temperature,load,idler diameter,conveyor belt running speed,thickness of the bottom cover of conveyor belt and steel code pitch on the indentation rolling resistance was analyzed.Compared with the calculation results of QC-N indentation rolling resistance analysis method,the validity of the finite element method was verified.