Testing Polyester Fiber Rope for Six Change-in-Length Properties (6 CILP)

摘要

This paper discusses recent advances in understanding how the length of a fiber rope changes under various tension conditions and histories. The change-in-length characteristics of polyester rope can be completely represented by six properties: original stiffness, static stiffness, dynamic stiffness, construction strain, polymer strain, and working strain. This is called the 6 CILP method. This paper describes a multi-step test procedure to measure these six properties. The tests need only be performed once for a particular rope design. The measured properties are generally independent of the rope size and strength. Thus they can be applied to any rope of the same fiber material and construction. The measured properties are not unique to the loading history used during testing. Thus they can be used to predict the rope performance under any tension condition and history. The calculation procedures are described in the companion paper "Use of Six Change-in-Length Properties (6 CILP) in Designing Fiber Rope Mooring Systems." This paper briefly describes the test program which was conducted to develop the test methods. It describes how the change-in-length properties are calculated from the test results. It also presents the properties which were determined for a particular type of polyester rope. The paper will be of interest to makers and users of polyester and other synthetic fiber ropes. It will be of particular interest to designers of deepwater mooring systems.