Tension optimization of the conductor-and-support cable elements during stranding process

Abstract

Steel lifting ropes, cables and other similar products are rod statically undeterminable prestressed structures. Preliminary deformations of their elements (wires) are caused by their manufacturing technology. Wires suffer stretching, bending with torsion in a stage of elastoplastic deformation. In this work the mechanic-mathematical model of residual forces determination in the wires of polymetallic conductor-and-support cable is offered. Aim: The aim of the work is studying of the mechanical and mathematical model defining residual forces in the wires of conductor-and-support cable and also the optimization of parameters of a twist by the criterion of residual forces lack after production process finishing. Materials and methods: The method developed by the authors earlier to the study the strain-stressed state of twisted wire products off-loading from technological internal forces has been applied to assess the impact of the approximate value of the longitudinal stiffness of the product. In this paper, each wire is considered as an element of the product individually. This is necessary to investigate the impact of uneven wire tensions on defects of conductor-and-support cable (out-of-straight in a free state and stripping-down). Results: On the basis of the conducted deformation studies of conductor-and-support cable during off-loading process from twist tension of its elements the dependencies of residual forces on the level and interrelation of elements tension has been determined. The condition of ensuring of zero residual forces in the wires of conductor-and-support cable after production is formulated. It was found that calculated values of residual forces are almost identical when using of the approximate and exact values of longitudinal stiffness of conductor-and-support cable.