Effect of Friction on Coupled Contact in a Twisted Wire Cable

Abstract

A strand or cable consists of a central core surrounded by a number of wires wound helically in a single layer or multilayers. There are three modes of contact in a simple straight strand. The first type is a core-wire contact in which the wires in the layer are in contact with the core only. In the second type, the wires in the layer are in contact among themselves and not with the core, while in the third type there is a coupled contact among the core and all the wires. Most literature handled the cable assembly with either the core-wire or the wire-wire contact because of the simplicity of the loads acting in these distinct contact modes. An attempt is made in this paper to model the strand with a coupled core-wire and wire-wire contact and deduce its equations of equilibrium. The numerical analyses of strand force, twisting moment, strand stiffness, contact force, and contact stress are carried out based on the equilibrium of thin rods and the results are compared with earlier research works. The importance of the inclusion of interface forces and their effects is studied.

Response of a wire rope strand to axial and torsional loads: Asymptotic modeling of the effect of interwire contact deformations

“…(12) in the mentioned paper) results in an indeterminate form as the coefficient of friction tends to zero. Note also that since Gnanavel et al (2010) do not consider the effects of local contact deformations, their results cannot be applied in the frictionless case.…”

“…The case of coupled contact between the core and all the wires was recently considered by Gnanavel et al (2010) under the assumption of existence of interfacial frictional forces described by Coulomb's law. It should be noted that the obtained expression for the normal line contact force between the wires (see Eq.…”

Effect of interfacial contact forces in radial contact wire strand

“…An arrangement of six helical wires of radius 4.871 mm wound around a central core of radius 5.129 mm is chosen for the computation of the static behaviour. This geometry which yielded a coupled core-wire and wire-wire contact had been elaborately dealt with in the paper by Gnanavel et al [7,8] and found to exist in coupled contact mode up to a lay ratio of 7.8 and turned into core-wire radial contact afterwards. To explain the behaviour of the strand under core-wire radial contact, along with the interfacial contact effects, the same geometry adopted by Gnanavel et al [7,8] has been chosen.…”

“…This geometry which yielded a coupled core-wire and wire-wire contact had been elaborately dealt with in the paper by Gnanavel et al [7,8] and found to exist in coupled contact mode up to a lay ratio of 7.8 and turned into core-wire radial contact afterwards. To explain the behaviour of the strand under core-wire radial contact, along with the interfacial contact effects, the same geometry adopted by Gnanavel et al [7,8] has been chosen. Further the geometrical data of the cable has been chosen, in line with a similar research work carried out by the Costello [2] group, to explain the additional features of interfacial contact forces resulting in the axial slip and rotational slip of the helical wire on the core.…”

“…A mathematical model to represent the effect of tangential and normal distributed forces in a coupled contact is formulated by Parthasarathy [6]. Gnanavel et al [7,8] have presented an analytical model to explain the importance of the interfacial loads and their effects in coupled contact and identified the threshold limit at which the contact mode changes from a coupled arrangement to the arrangement of core-wire contact. Under the axial loading of the strand, the wires develop a clenching effect on the core, thereby causing a radial deformation.…”