Modeling the Stress-Strain Properties of Synthetic Fiber Mooring Lines under Cyclic Loading

摘要

The nonlinear stress-strain relationship of synthetic fiber ropes underrncyclic loading is a property of vital importance which directlyrninfluences the dynamic tension response of mooring lines. How torncapture the load-elongation relationship of the synthetic fiber mooringrnlines under cyclic loading and obtain the quantitative description is arnkey problem which would be of interest to mooring system designers,rnplatform operators and researchers. The former studies wererninsufficient to take into account the true loading history, creep behaviorrnand the evolution of the dynamic stiffness. A viscoelastic andrnviscoplastic model is developed herein to describe the stress-strainrnproperties of synthetic fiber mooring lines. The total strain isrndecomposed into a recoverable viscoelastic strain and an irrecoverablernplastic strain. The time-dependent property and the evolution of therndynamic stiffness can be fully incorporated in the developed model.rnThe model is examined by comparing with the experimental results ofrnpolyester ropes under both creep-recovery and sinusoidal loadings.rnThrough a detailed parametric analysis, further knowledge of thernhysteresis loop and the dynamic stiffness evolution is clearly obtained.rnThe present work is beneficial to improving the understanding of thernperformance of synthetic fiber ropes, and also provides a better basisrnfor the further research on the mechanical problems of synthetic fiberrnmooring lines under complicated loading conditions.