Fatigue and Weatherability Studies of Aramid-Fiber Rope Slings

Tests were carried out on twenty-six sling-leg specimens, fabricated from aramid-fiber ropes, as part of a program to develop improved external cargo slings for helicopters. The ropes included both parallel-strand and cabled-strand varieties, in three different tensile capacities. The tests were intended to evaluate the reductions in rope strength caused by fatigue loading and by exposure to simulated weathering. It was found that the fatigue capabilities of some of the ropes may not be entirely satisfactory; but, because of inadequacies in the end fittings installed by the rope manufacturers, thorough evaluations were not possible. The results indicate that the performances of the ropes could be enhanced through the use of more efficient end fittings, and suggestions for the development of such end fittings are offered. (MM)