An Energy Approach for Rope-strength Prediction

In this paper, an energy method is presented to predict the static tensile strength of double-braided ropes which are composed of two separable layers. An actual constitutive relationship of individual rope components is employed, so this approach is valid for predicting the whole stress/strain curve of ropes. Extremes of zero-friction and infinite-friction conditions are explicitly considered. Experimental results agree well with the predictions for small nylon and polyester-fiber ropes. In particular, experimental-failure strains lie between the limits predicted by the above two extreme conditions owing to a realistic partial-frictional constraint. The predictions obtained from a force-balance method are also included for comparison. The discrepancy is then discussed.