Cyclic fatigue testing of surface mooring hardware for the Arabian Sea mixed layer dynamics experiment
Cyclic fatigue testing of surface mooring hardware for the Arabian Sea mixed layer dynamics experiment
Date
1995-12
Authors
Trask, Richard P.
Weller, Robert A.
Weller, Robert A.
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Date Created
Location
Arabian Sea
DOI
10.1575/1912/518
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Keywords
Cyclic fatigue
Mooring hardware
Mooring hardware
Abstract
The Arabian Sea is strongly forced by monsoon winds. Surface moorings deployed in the Arabian Sea are
exposed to high winds and large waves. The waves, generated by strong wind events, impose a dynamic load
on all mooring components. The dynamic cycling of mooring components can be so severe that ultimate
strength considerations are superseded by the fatigue properties of the standard hardware components.
Concerns about all in-line mooring components and their fatigue endurance dictated the need for an
independent series of cyclic fatigue tests. The components tested included shackles of various sizes and
configurations, wire rope, instrument cages, chain, and a variety of interconnecting links such as weldless
sling links and end links. The information gained from these tests was used in the design of the surface
moorings deployed in the Arabian Sea by the Upper Ocean Processes group of the Woods Hole Oceanographic
Institution.
The results of the cyclic fatigue tests conducted in support of the Arabian Sea surface mooring design effort
are presented in this report. Recommendations are made with regard to all in-line components for surface
moorings where dynamic conditions might be encountered for extended periods. The fatigue test results from
shackles, and sling links were compiled to generate an SIN diagram where the cyclic stress amplitude is
plotted versus the number of cycles to failure. In addition, the wire rope test results were compiled with
historical wire rope data from US steel to generate a SIN diagram for torque balanced 3x19 wire rope. These
results can be used in conjunction with
future design efforts.
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Trask, R. P., & Weller, R. A. (1995). Cyclic fatigue testing of surface mooring hardware for the Arabian Sea mixed layer dynamics experiment. Woods Hole Oceanographic Institution. https://doi.org/10.1575/1912/518