Study On Mechanical Characteristics Of Shearer Cable

The shearer cable provides power and control signals for the shearer,and its working performance and service life are particularly important for the mining efficiency of the shearer and the safe operation of the underground power supply system.Due to the complex and harsh environment of the comprehensive mining face,the cable will be subjected to different degrees of bending,extrusion,dragging and the impact of falling coal blocks and other mechanical forces during the working process,and the cable often does not reach the normal service life and other problems such as insulation damage,conductor tensile overload,and core fatigue fracture,resulting in its service life not only can not meet the needs of on-site use,but even causes major accidents such as short circuit and grounding.In this paper,MCPT-1.9/3.3 3*120+1*70+4*10 shearer cable is used as the research object to explore the mechanical characteristics of the cable under tensile and bending conditions.Firstly,the structure of the shearer cable is analyzed,and the three-dimensional model of the cable and the accurate geometric model of the conductor of the power core and ground wire core are established based on CAD modeling technology and cable manufacturing process.Based on the tensile test to measure the elastic modulus of the strand,and predict the equivalent elastic modulus of the cable power core and ground core conductor through differential geometry theory and static theory,the influence law of the inner and outer stranded joint diameter ratio on the equivalent elastic modulus was analyzed,which provided a theoretical basis for the simplification of the cable model.Combined with the actual working conditions of cables and MT818 coal mine cable industry standards,the finite element model of cables under tensile and bending conditions was established,and the force and deformation displacement of each layer structure of cables under different cable pitch ratios were analyzed by Workbench LS-dyna software.Based on the cable bending simulation results,the fatigue life analysis of the cable was performed using n Code software.The results show that the equivalent elastic modulus of the conductors of the power core and ground core of the cable gradually increases with the linear increase of the diameter ratio of the inner and outer stranded joints,and the growth range gradually decreases.When the cable duct is blocked,deformed or the cable clamp is superimposed for many times,it may cause the cable tension overload,so that the conductor core reaches yield strength or even breaks,so under the cable stretching condition,assuming that the cable duct is blocked,the cable clamp suddenly stutters,the shearer continues to move during the cable is stretched,and the tensile load is set to one end of the cable fixed and the other end is applied 6m/min traction speed,the simulation time is 0.1s,and the power core conductor under the sudden working condition is obtained,The maximum stresses of the ground core conductor and the control core conductor were 245.78MPa,254.26MPa and 186.54MPa,respectively,and the displacement deformation of the cable was distributed in layers from the stuttering end to the tensile end.According to MT818 coal mine cable industry standard,the working conditions of shearer cable are not less than 6 times the outer diameter of the cable,and the simulation analysis of the cable bending condition shows that the maximum stress of the power core conductor,ground core conductor and control core conductor under the action of bending load is 158.08MPa,153.49MPa,168.31MPa,the conductor core is in the elastic stage,and the displacement deformation gradually increases from the middle constraint part to both ends.By changing the pitch ratio of the cable,the stress of the cable conductor under both working conditions is obtained,and the stress increases with the increase of the pitch ratio.Under bending conditions,the fatigue cycle times of the power core conductor,ground core conductor and control core conductor of the cable are 5.99*10~4,6.475*10~4and 5.152*10~4,respectively.The research results of this paper can provide a theoretical basis for the structural design and process parameter optimization of shearer cables,so as to improve the working performance and service life of shearer cables.The paper has 58 figures,7 tables,and 85 references.