Prediction of axial hysteresis in locked coil ropes

Abstract

In published literature, the strand constructions dealt with have almost invariably involved only wires which are circular in cross-section. There are, however, instances when shaped wires are used in, for example, half-lock and full-lock coil constructions.The paper reports details of a theoretical model which enables an insight to be gained into various characteristics of axially loaded lock coil ropes. The model is based on an extension of a previously reported orthotropic sheet concept and provides a fairly simple means of estimating wire kinematics, interwire/interlayer contact forces, effective axial stiffnesses and axial hysteresis in axially preloaded locked coil ropes experiencing uniform cyclic axial load perturbations. The theory takes interwire contact deformations and friction into account.Final numerical results based on theoretical parametric studies on some substantial cables highlight the substantial role that the outermost layer(s) with shaped wires play as regards the overall axial damping capacity oifully bedded-in (old) locked coil ropes, and it is found that (for the same lay angles and outer diameters) axial hysteresis in locked coil ropes is generally higher than spiral strands which are composed of only round wires. This finding may have significant practical implications in terms of the design against dynamic instability of structures supported by such cables.

Experimental Study on Corrosion of Galfan‐Coated Full‐Locked Coil Ropes in a Natatorium Environment

“…e corrosion rate of the section is expected to be about 55% in 40 years. e CR of the secondary layer wire can be fitted linearly [16], and the complete corrosion can be predicted in 5.8 years. It can be noted that the high stress accelerates the CR of the cable, and the corrosion rate of the secondary layer wire is faster than that of the outermost layer wire.…”

Numerical Investigation of 1 × 7 Steel Wire Strand under Fretting Fatigue Condition

“…The modulus of elasticity was 202 GPa and Poisson’s ratio is 0.28 [15,21]. In addition to the elastic information, stress–strain information after yielding was also provided [21] and the wire strand was subjected to loading below 50% MBL but as the stresses were more in the trellis point of contact region [5,6], plasticity could not be ignored. A hexahedral mesh element C3D8R was employed for the discretization of the entire strand with a total number of 128260 elements and 160710 nodes shown in Figure 1.…”

“…These localized stresses affect the elastic, hysteretic and fatigue properties of wire ropes. These contact points have received more attention by researchers [4,5,6,7] due to their major contribution in the failure of wire ropes. In many designs of wire ropes, this trellis contact is minimized by using some lubricants between layers of wires.…”