Constitutive Simulation of Synthetic Fibers for Offshore Mooring Under Cyclic Loading: Hysteresis Stabilization and Stiffness Evolution

Resumo

The mechanical performance of synthetic fibers used in offshore mooring systems is strongly influenced by their nonlinear response under cyclic loading. This study presents a constitutive simulation framework aimed at capturing the complex cyclic behavior of different synthetic fibers, particularly focusing on hysteresis stabilization and stiffness evolution during repeated loading cycles. The proposed model is grounded in hyperelastic theory, adopting a modified Yeoh strain energy density function to represent the fiber material response.The simulations are driven by a parametric optimization strategy based on continuum mechanics principles, involving iterative fitting between stress and strain tensors. This approach enables the calibration of model parameters to reflect the progressive mechanical behavior observed in experimental cyclic tests. By incorporating multiple loading cycles into the analysis, the model captures the gradual stabilization of mechanical hysteresis and tracks changes in normalized stiffness throughout the loading history.The results highlight the capability of the modified energy-based model to reproduce key features of fiber cyclic behavior, including load-unload asymmetry, residual strain accumulation, and nonlinear stiffness degradation. Additionally, the study demonstrates the sensitivity of the constitutive parameters to the number of cycles required for hysteresis stabilization, providing insights into the fatigue-like mechanical adaptation of fiber structures.This framework offers a robust foundation for integrating synthetic fiber behavior into larger-scale offshore system simulations, contributing to more accurate mooring design under realistic loading conditions. The proposed method can be adapted for different synthetic fiber types and extended to multi-scale modeling approaches, strengthening the predictive capability of offshore engineering tools.