Testing of Ropes

Published On:Feb 22,2018

Strength evaluation dominates, by far, all the tests that might be run on fibre ropes. This seems obvious since when anyone thinks of any kind of rope, the first thing that comes to mind is, ‘How strong is it?’. However, there are many other tests that are conducted to measure the various properties of fibre ropes or those of the fibres from which they are made. Some of these properties may be more important than strength alone in certain applications.

Reasons for testing

  • Background: The reasons for conducting tests are as varied as the tests themselves. This background is useful for gaining an appreciation of the significance of testing in the developments, production, and use of the rope. Some of the more important tests are discussed in other points.
  • Quality Assurance: An acceptable quality assurance programme for rope production requires frequent type treatment, performance specification, and size. During the various stages of production, the ply count and twist levels of the rope components should be checked at some specified frequency.
  • Design and Specification: Fibre ropes often cannot be reliably designed to meet a specific strength specification without verification by testing. Unless changes from a known design are relatively small, knowledge of just the fibre properties may not be enough to accurately predict the strength of a new product. Also, strength will vary with size but not always in ratio with the amount of fibre present in cross-section.
  • Residual Strength: All Fibre ropes gradually lose strength and extensively with use. Knowledge of rates of degradation is important for safety and economy. A number of tension-tension fatigue tests on large ropes have been carried out in the joint industry studies sponsored by offshore oil-related organizations interested in deep sea mooring. These have been useful in gaining an understanding of the behavior of the particular ropes that were tested in this specialized application.
  • Research or Special Applications: Testing for various forms of fatigue and creep is usually done under research programmes to make life predictions. Sometimes a test programme will be undertaken for one specific application, such as deep sea mooring of floating oil production platforms.