A general fractional model of creep response for polymer materials: Simulation and model comparison

The creep deformation of polymer materials is a major concern to ensure the safety and reliability of structural designed parts. In this work, a novel fractional creep model is established by introducing the superb Almeida-Caputo fractional derivative into the traditional viscoelastic constitutive equation. The kernel function is determined by conducting several simulations of uniaxial creep tests, making it more flexible and reliable to provide excellent description of creep deformation. Compared to the traditional fractional model, the proposed model exhibits higher accuracy and better performance, and is found to have the ability to depict the nonlinear time-varying characteristic at accelerated creep stage. Furthermore, the physical significance of fractional order is explored by performing the sensitivity analysis of model parameters, the results revel that the order is closely associated with the evolution of material properties where the diagrams of creep deformation of polymer materials under elevated temperature and stress levels could be mirrored by the variation of fractional order.

Automated summary

A novel fractional creep model was established in this study, showing higher accuracy and better performance compared to traditional models, with the ability to describe nonlinear time-varying characteristics. The physical significance of fractional order was explored through sensitivity analysis, revealing the correlation between the order and material property evolution.