Modeling the nonlinear creep behavior of Entandrophragma cylindricum wood by a fractional derivative model

Wood, favored for its renewable nature and ease of shaping, is widely used as a structural construction material. However, once in service, wood undergoes creep. This paper delves into the nonlinear creep behavior of Entandrophragma cylindricum wood, known in Cameroon as Sapele, using rheological models based on fractional derivatives. The classical eight-parameter Kelvin–Voigt rheological model and the fractional rheological models of Zener, Thomson, and Burger are employed for modeling. The rheological parameters for these models are determined through an optimization algorithm. The results reveal that the classical model encounters difficulty in describing the experimental data, whereas the fractional models offer a better fitting. Notably, among the fractional models, the Thomson model predicts Sapele creep with an accuracy of 98%.