Wire Rope Terminations, Section, And Replacement Criteria

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ABSTRACT Selection, inspection, and replacement criteria for wire rope terminations have evolved as an empirical art based generally on the experience of the user. The series of tests described in this paper provides a database upon which to build a scientific approach to wire rope termination use. Extensive tests of nine well known terminations were performed using both static and dynamic loads, and five wire rope sizes. Also tests were made to evaluate the sensitivity of each termination to incorrect or faulty installation. INTRODUCTION Wire rope terminations are a necessary and important part of any wire rope system and merit the highest consideration of the designer and user. Traditionally selection, inspection, and replacement criteria have been based on past experience with very little comprehensive testing or analysis. The test results reported herein utilized nine of the best known wire rope terminations subjected to static and dynamic loading, and consider variations in the wire rope itself, and termination installation requirements. This research was conducted by Engineering Services co., Demascus, Maryland for the Bureau of Mines under contract HO 166079, and while wire rope applications to the mining industry were considered of primary importance in designing these tests, there is no reason why this information cannot find wide applications in the marine and off-shore industry. Wire Rope Termination Tests The nine wire rope terminations selected for this series of tests are illustrated in Figure 1 and are listed as follows:Flemish loop with steel sleeve and thimbleFlemish loop with steel sleeve, no thimbleWedge socketSwaged socketTurn back loop with aluminum sleeve and thimb1eThinble splice with four tucksU-Bolt clips with thimbleZinc poured socketEpoxy resin poured socket. All of these termination devices except #9, epoxy, resin poured socket, which is relatively new, are well known and time tested, each with unique features which often dictated its application. In the design of the test matrix one objective was to be completely objective, and another was to introduce as many variables as possible. The test specimens used were fabricated using five wire rope diameters: 13mm (½inch), 19mm (3/4 inch), 25mm (1 inch), 38mm (1½inch), and 51mm (2 inch 6x19 and 6x37 classification, Warrington (no filler wires), improved plow steel (IPS), bright (BRT) (not galvanized), form set (FS) Lang lay and regular lay construction, and with independent wire rope core (IWRC). The test specimens were made up of short lengths of wire rope with the terminations to be tested on each end such that the gage length included two lay lengths. The load spectrum applied was either pure tension (pull test) or an oscillating dynamic load (service life test). The pull tests were conducted in a horizontal bed test machine, with an increasing axial load applied until failure occurred. At this time the maximum load and details of the failure were recorded. All of these termination devices except #9, epoxy, resin poured socket, which is relatively new, are well known and time tested, each with unique features which often dictated its application. In the design of the test matrix one objective was to be completely objective, and another was to introduce as many variables as possible. The test specimens used were fabricated using five wire rope diameters: 13mm (½ inch), 19mm (¾ inch), 25mm (1 inch), 38mm (1½ inch), and 51mm (2 inch 6×19 and 6×37 classification, warington (no filler wires), improved plow stee