Determination Of Friction Coefficient Of Parallel Wire Bundles And Analysis Of Contact Effect

As the main load-bearing component of the bridge,the steel cable is generally wrapped with PE plastic and is in a high stress state.When the steel wire is partially bent,the shear force generated inside the cable may cause the steel wire between the steel wires or the steel wire and the sleeve to slip and break the integrity of the cross section.Whether or not the steel wire is slipped depends on the relationship between the ultimate frictional stress between the wires and the shear stress caused by bending between the wires.The ultimate frictional stress is determined by the coefficient of friction between the wires and the normal contact stress inside the cable.Starting from these two aspects,the paper experimentally determines the friction coefficient between parallel steel wire bundles,and numerically simulates the bending contact between parallel steel cables and parallel steel strands.Theoretical and experimental research on the bending and anti-slip properties of steel cables provide a reference for the calculation of the bending stress of the cable structure,thereby improving the safety and reliability of the cable.The main research work and conclusions of the thesis include:The issue of friction coefficient between parallel cables include the calculation of positive pressure and the determination of sliding friction.In this paper,the self-designed fixture is used for loading,and the sliding friction force is measured.The positive pressure is calculated by numerical simulation.Finally,the variation coefficient of friction coefficient between seven parallel steel wires with positive pressure is obtained.The results show that the friction coefficient of galvanized parallel steel wire decreases with the increase of positive pressure.The friction coefficient of seven steel wires is between 0.15 and 0.209.Compared with the friction coefficient of five steel wires,the friction coefficient is changed from 0.13 to 0.21.The friction coefficient of seven steel wires changes more uniformly and the corresponding coefficient of friction value is greater at the same positive pressure,compared with those of five steel wires,Based on the maximum contact normal stress in the cable under micro-bending state,the finite element numerical calculation method is used to compare the bending characteristics of the parallel cable and the parallel steel strand in the micro-bending state,and the two steel cables are different.The variation law of the maximum contact normal stress under forced vertical displacement,the influence of the elastic modulus of the steel wire,the friction coefficient between the steel wire,the prestressing force on the maximum contact stress,and the bending of the two cables under different engineering conditions are obtained.The variation law of the bending anti-sliding performance of the two cables under different engineering conditions is obtained,too.The results show that increasing the elastic modulus of the steel wire can improve the bending and anti-slip performance of the parallel cable,but it has little effect on the bending anti-slip performance of the parallel steel strand.Only when the bending deflection is large,increasing the friction coefficient between the wires can improve the bending anti-slip performance of the parallel cables.When the applied pre-tension is increased,the bending anti-slip performance of the parallel steel strands is less affected by the pre-tension of the parallel cable,and the performance is more stable.