Resaerch On The Properties And Reliability Of 3D Braided Carbon Fiber Rope In The Hoisting System For Deep Mining

Mine hoisting system is an important process in the ore production industry,and it is responsible for the lifting and transporting of ore,personnel and various materials and equipment.As an important equipment connecting the underground and ground,the lifting rope is the key component that determines the lifting capacity of the hoisting system.With the increasing of lifting depth and speed,the specific strength of the lifting rope is required to be higher.However,the greater the depth,the longer the lifting rope,and the more strength is used to counter the effects of dead weight,even the weight of ropes will greater than the hoist load,so the lifting capacity is limited by the ropes.Hence,it is necessary to to choose carbon fiber braiding rope which has higher specific strength to replace the steel wire rope.Based on the research of 3-D braided composite materials,the geometric model of 3-D braided carbon fiber rope was established in this paper,and the mechanical properties under tensile and bending loads were studied.The main research contents include:(1)By analyzing the periodic geometry of 3-D braided carbon fiber rope,the whole braided structure was divided into different representative unit-cell,and these periodic unit-cell models were used to form the whole model.Considering the difference between the braided structure on the surface and interior region,and take care of the influence of the odevity of row and column number,five kinds of unitcells were established,including interior unit-cells,surface unit-cells and corner unit-cells at different boundary.Because of the compressional deformation of braided structures,parameterized unit-cell models are established,and the geometric relationships between structural parameters and braided parameters are described by mathematical model.(2)A multi-scale homogenization method is introduced in the finite element analysis to connect the macroscopic model with the mesoscopic unit-cells.The equivalent displacement matrix and equivalent stiffness matrix are calculated by applying boundary conditions and boundary loads to the finite element model of mesoscopic unit-cells,and then the stiffness matrix of the whole is obtained by the stiffness volume averaging method.The experimental results and simulation data are compared to verify the model.(3)Based on the results of multi-scale homogenization finite element simulation results of mesoscopic unit-cells,a macroscopic finite element model of 3D braided carbon fiber rope was established,and the mechanical response under unidirectional tensile load was simulated.Based on the mathematical model which describes the relationship between macroscopic strain field and mesoscopic stress field,the mesoscopic stress field of unit-cells was calculated.Von Mises effective stress yield criterion and maximum tensile stress intensity criterion were used to judge the damage of the matrix elements,and the maximum tensile stress intensity criterion were used to judge the damage of the fiber bundle elements.Finally,the prediction model of tensile strength of 3D braided carbon fiber rope was established.The correctness of the model is verified by comparing the experimental results.(4)The mechanical response and strength analysis model of 3-D braided carbon fiber rope under bending load was established based on the multi-scale homogenization method.Due to the complex mesoscopic stress distribution under bending load,Tsai-Wu second-order tensor polynomial is introduced as the failure criterion for fiber bundles.Connecting with the stiffness reduction of damage unitcells,the bending strength of 3D braided carbon fiber rope was calculated.Comparing with the experimental results,the simulation date is basically consistent.(5)Based on the evolution-based uncertainty analysis method,the timevarying reliability calculation model for the dynamic anti-skid of the hoisting rope in different operating conditions was established,and the time-varying uncertainty analysis model for the tensile strength of the hoisting rope was established.