Research On The Mechanical And Wear Properties Of Braided Wire Rope Under Tension-Torsion Combined Load

In recent years,with the proposal of the national power grid construction plan of West to East power transmission,the number of cable tension erection projects is increasing day by day,and braided wire rope plays an irreplaceable role as an important tool for guiding and pulling the erection of cables.In the construction of the project,the braided wire rope is repeatedly affected by tension,torsion and its composite load,the stress condition is very complex,resulting in the deformation and wear of the wire rope,and the phenomenon of broken wire and strand,which causes serious safety hazards to the electric power construction.Therefore,this paper takes the braided wire rope as the research object and develops its mechanical and frictional wear performance under the action of tensile-torsional load with the help of theoretical analysis,numerical simulation and experimental research based on the cable tension erecting working condition as the background,which has important theoretical significance and application value for improving the structure and life prediction of the braided wire rope.Combined with the cable tension erection condition,this paper carried out the analysis of the causes of the tensile,torsional load and friction and wear for the YS9-8×19 square braided wire rope,and quantitatively explored the friction force that caused the torsion of the rope body.The mechanical analysis of straight rope strands under tensile and torsional loads was carried out,and the mechanical models under tensile and torsional loads were obtained.The ellipse approximation method was used to expand the braided wire rope strand into straight strand.The stress analysis of the braided wire rope strand under the tension torsion load was carried out.The expression of the axial strain of the braided wire rope strand under the composite load was derived,and the mechanical model under the tension torsion composite load was constructed,which lays the theoretical foundation for further discussion of the mechanical response and friction wear performance of the braided wire rope strand.Based on the elastic theory of Costello wire rope and taking the wire as the research object,the mechanical state of the strand side wire mechanical equilibriumequation was established by analyzing the state of the load under the tension-torsion composite load.According to the mechanical balance equation of the side wire of the rope strand,the expression of the relationship between the axial tension of the strand and the axial strain of the core wire and the stress and strain expression of the inner and outer layers of the strand were derived,and the mechanical response model of the rope under the combined load of tension and torsion was established.At the same time,the numerical simulation of the braided wire rope under the tension torsion composite load was carried out,and the stress and strain of the braided wire rope under the tension torsion composite load were obtained.The comparison between the theoretical model solution results and the numerical simulation results proves the consistency of the section equivalent stress and the axial deformation trend of the wire rope.According to the actual wear condition of the braided wire rope,the contact state of the wire between the strands of the braided wire rope was analyzed,and the equation of the change of the elliptical contact area of the two wire wires with the sliding stroke was obtained.Based on the contact state between the wires,the wear volume model of the wire was established by solving the wear coefficient and the contact pressure,which provides a theory guidance for quantitative analysis of the wear degree of the strands.Based on YS9-8×19 braided wire rope,the expressions of contact angle and relative sliding distance between outer side wires of braided wire rope strand were deduced,and the solutions of contact angle,relative sliding distance between rope wires and wear volume of rope wire were carried out with the help of Matlab mathematical programming software.The results show that the theoretical wear volume of rope wire increases with the increase of contact angle,and the rope is seriously worn under the larger contact angle.Combined with the structure of braided wire rope,a friction and wear experimental device with a changeable contact angle of wire rope was developed.With the help of mft-5000 high integrated multi-functional friction and wear tester,the friction and wear tests of the outer side wires of the rope strand at different contact angles were carried out.The morphology of the wires after the test shows that thelength and width of the friction marks gradually decrease,and the wear degree and wear depth of the rope gradually increase with the increase of contact angle.The wear volume is calculated after the test,and the test results are compared with the prediction results of the model.The accuracy of the model is verified,which provides a basis for further life budget and structural improvement of the braided wire rope.