Structural Modeling of Double-Braided Synthetic Fiber Ropes

Abstract

This study is primarily concerned with the performance of double-braided ropes. widely used in marine applications. The mechanical properties of such ropes are ob tained by combining their structural features and the constitutive behavior of individual rope components. Emphasis in this study is on the tensile behavior of straight ropes as well as bent ropes, either an eye splice or in a continuous loop around a bollard- like pin. In the former case, precycling and water effects on the model predictions are discussed. For new small ropes, bending rigidity is negligible, so the bending effect is considered by modifying the geometry of the rope to allow for variation of helix periods and change of cross-sectional shapes from circular to elliptical ( flattened ) . For two extreme frictional conditions considered, i.e., infinite and zero friction, predictions of small nylon rope behavior agree well with experimental results for both simple tension and tension plus bending. There is less agreement for small PET ropes, par , ticularly in bending tests.