An upper and lower bound method for evaluating residual strengths of polyester mooring ropes with artificial damage

Abstract

Polyester ropes have been widely used in various ocean engineering. In practice, the occurrence of damage degrades polyester rope strength and causes mooring rope failure. To ensure operational safety of polyester mooring ropes, an experimental method and associated procedure for investigating the residual strength of damaged ropes are proposed. The experimental investigation on the residual strength of damaged ropes is performed and the test results show that the first failure time and the threshold failure loading level of the yarns in damaged rope decrease with the increase of the initial damage level of fiber ropes. The test results also prove that the residual strength decreases with increasing damage level. Besides, an empirical equation for predicting the residual strength of damaged ropes is proposed from the dimensional analysis. Moreover, an upper and lower bound method is proposed to evaluate the residual strength of polyester mooring ropes. The present study helps to understand the strength attenuation of damaged polyester ropes and provides a scientific reference for the safety design and maintenance of polyester mooring ropes.