| With the continuous development of the current world economy,belt conveyors are also developing in the direction of large capacity,high belt speed and long distance.Among the various costs of conveyors,the cost of conveyor belts accounts for about 40% and the cost of idlers accounts for 25%.These two kinds of components accounted for about 65% in the total cost of conveyor.Among the resistance factors which produce power consumption,the indentation rolling resistance of the conveyor belt accounts for 63% in the total resistance,and the idler rolling resistance accounts for about 9%.The various calculations of the conveyor,such as belt speed,tension,width of conveyor belt,idler spacing,start brake control,driving layout,etc.,also assumption that the conveyor belt is elastic or linear viscoelastic material.The speed,radius and rolling resistance of the idler directly affect the indentation resistance and stress distribution of the conveyor belt.Therefore,the research on conveyor belt and idler has practical economic needs and theoretical significance.This article uses a combination of theoretical analysis and simulation experiments to study the indentation rolling resistance as the belt crosses the idler and the stress distribution of the conveyor belt under full load.The main research results are as follows:1)According to the characteristics that conveyor belt is a high polymer matrix viscoelastic composite,the steel-reinforced belt and aramid conveyor belt,which have a larger proportion in current conveyor belts,are used as the research objects.The conveyor belt is divided into cover rubber layer and core layers for analysis.Dynamic mechanical thermal analysis(DMTA),thermal stretch,hysteresis,vibration,and adhesion tests on the cover layer and core layer are conducted.The microstructure of each layer through SEM and TEM is observed and interpreted from the perspective of phenomenology.In this way,the internal deformation mechanism is explained,and experimental data for the constitutive model is provided.2)Combined with the previous test data,assuming that its volume remains unchanged,through functional and tensor transformation,a nonlinear viscoelastic integral relaxation constitutive model based on incompressible materials and finite deformation theory is constructed.Combined with laminate theory,a new type of nonlinear viscoelastic integral relaxation constitutive model of integral conveyor belt is finally derived.3)Aiming at the steel-reinforced belt,the space mathematical model of the steel cord is established,and the material defined by the above model is introduced into the software,and the finite element analysis is performed on it.Combined with the experimental results,the correctness of the constitutive model of the steel-reinforced belt relaxation is verified;Similarly,the finite element simulation of the aramid conveyor belt,combined with the experimental results,jointly verified the correctness of the constitutive model of aramid conveyor belt relaxation.4)Through the mechanical analysis of the contact area between the conveyor belt and idler,the variation mechanism is expounded and the indentation resistance model based on the new constitutive equation is deduced.The MATLAB simulation and experiments are carried out to verify the correctness of the new indentation resistance model.5)The stress distribution of conveyor belt under full load is analyzed by the coupling method of EDEM+ANSYS.The test results of others are combined to verify the correctness of the simulation and further verify the correctness of nonlinear viscoelastic constitutive model and Indentation resistance model of the conveyor belt.On this basis,the necessary optimization and reliability analysis of the supporting idler are carried out.In this paper,through theoretical deduction,simulation analysis and experimental verification,the constitutive model of the conveyor belt,indentation rolling resistance,and the stress distribution law of the conveyor belt at full load are studied.This paper proposes a non-linear viscoelastic relaxation constitutive model for the current mainstream high-strength conveyor belt and validates it through simulation and experiments.Based on this,a new indentation resistance model is constructed and the stress discontinuous distribution under full load is analyzed.The necessary optimization and reliability analysis of the supporting idler are carried out.The results of this research can provide theoretical support for the development of our country's conveyors-long distances,large capacity,and high-speed.The nonlinear viscoelastic constitutive model proposed in this paper and the indentation rolling resistance model,stress discontinuity model have important theoretical significance and application value. |
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