A viscoelastic-plastic model for the temperature-dependent creep and recovery behavior during dry fiber fabric compaction

The preforming process of dry fiber fabric usually involves compaction under constant pressure and specific temperature during fiber-reinforced composite manufacturing. The fabric exhibits time- and temperaturedependent considerable permanent deformation and creep/recovery behavior in compaction. A better understanding of these phenomena, combined with the ability to predict the behavior, will contribute to better control of fiber volume fraction and material composition. This study presented a universal viscoelastic-plastic model to represent the fabric's visco-effect in compression and recovery stages. The proposed model consisted of a modified Burges element for time-dependent deformation and a plastic element for permanent deformation that occurs in all cases. It used only one set of equations and one set of parameters to characterize the cyclic loading/ unloading and the compaction and relaxation phases. It could consider the material densification effect observed experimentally. The model was validated against experimental data for unidirectional (UD), plain woven, and twill woven fabrics. A reasonable match between experiments and prediction was achieved under different compression scenarios.