Analysis of Large Diameter Steel Ropes

Simple determination of the axial stiffness for largediameter independent wire rope core or fibre core wire ropes

“…references [1] to [3]), Velinsky [4,5], Lee et al [6] and Lee [7,8]. All these theoretical developments for wire ropes have, however, ignored the important effects of interwire friction and contact deformations: both of these effects are fully catered for by Raoof and Kraincanic [9], who have also demonstrated that, for example, Velinsky et al's [2] predictions of axial stiffness for wire ropes with an IWRC, which are based on largely the same basic assumptions as those adopted by Costello and his other associates (e.g. references [1] and [3]), are not supported by the carefully conducted large-scale experiments of Strzemiecki and Hobbs [10] on a 40 mm outside diameter wire rope with an IWRC, with the length of the specimens ranging from 2.9 to 7.16 m. Jiang [11] has also reported a frictionless theoretical model for wire ropes with an IWRC, the predictions of which are very close to those of the theoretical model proposed by Velinsky et al [2], with both models suffering from similar limitations.…”

“…It should be noted that the denominator in equation (1) is equal to the total net steel area in the wire rope's normal cross-section, with the shapes of individual round wires and spiral strands in the wire rope's normal crosssection being elliptical [9,13] and the central (king) wire in each spiral strand having a 1ˆ0 . According to equation (1), the dominant parameters controlling the rope axial stiffness are the lay angles …b j † of the strands in the wire rope and also the lay angles …a i † of the steel wires forming the individual spiral strands, with the parameter A Li also playing a role.…”

“…The original theoretical models of Raoof and Kraincanic for wire ropes [9,13], although being very reliable, suffer from the potential drawback of being mathematically rather complex. Developing simple routines, which are amenable to hand calculations using a pocket calculator, similar to those for spiral strands, as already reported by Raoof [14], is therefore highly desirable and forms the purpose of the present paper.…”

“…Developing simple routines, which are amenable to hand calculations using a pocket calculator, similar to those for spiral strands, as already reported by Raoof [14], is therefore highly desirable and forms the purpose of the present paper. In what follows, based on an extension of the work of Strzemiecki and Hobbs [10], in conjunction with numerical results based on Raoof and Kraincanic's models [9,13], simple formulations will be developed for estimating the no-slip and full-slip axial stiffnesses of wire ropes, with either a ®bre or an independent wire rope core, which should prove of value to busy practising engineers.…”

“…1 A typical six-stranded wire rope with: (a) an independent wire rope core (IWRC) (after Lee [8]) and (b) a ®bre core (after Velinsky [5]) predicting, with a good degree of accuracy, the mechanical characteristics of spiral strands under not just static monotonic loading (which, incidentally, is the type of loading the previously reported frictionless theoretical models have primarily been developed for) but also when the strands experience cyclic loading. The results from the orthotropic sheet concept were subsequently used by Raoof and Kraincanic [9,13] to develop two somewhat different theoretical models for analysing the various stiffness characteristics of wire ropes with either a ®bre or an independent wire rope core. As originally shown by Raoof and Hobbs [12], in repeated (cyclic) loading regimes, due to the presence of interwire friction, the effective axial stiffness of axially preloaded spiral strands (with their ends ®xed against rotation) varies (as a function of the externally applied axial load perturbations/mean axial load) between two limits.…”