The present study investigated stress relaxation in fabrics with increased elasticity. For prediction of the degree of stress relaxation the frequently used mechanical models reported in the literature were analyzed. The mechanical models which were used in this paper were: Maxwell's model, the two-component Maxwell's model, the modified model of standard linear solid, Alfrey's model and the three-component Maxwell's model with nonlinear spring for explaining the 1 hour relaxation curve and the 24 hour relaxation curve. The results of the study show that it is hard to precisely predict the value of stress after 24 hours using the model that was built up based on the 1 hour experimental curve. When comparing the experimental relaxation curve with the fitted curve from the mechanical model it is clear that the models with higher component values explain the experimental relaxation curve better. The weak point of those models was the high number of local minima which makes it difficult to find the global minimum.

PurposeIn this paper, special attention is focused on the study of the relaxation phenomena of fabrics containing elastane yarn.Design/methodology/approachFor this purpose, the relaxation phenomena of wound fabric under constant deformation, as the consequence of accumulated stress during winding, were analysed. Maxwell's model and the modified standard linear solid model are used for explaining the relaxation.FindingsThe results of the study of the relaxation phenomena of fabrics containing elastane yarn show a close connection between stress relaxation under constant deformation in the fabric roll and the degree of deformation with manual unwinding. Expert knowledge of the relaxation phenomena in fabrics containing elastane yarns has a big influence on explaining the problem of dimensional changes and instability in such fabrics.Originality/valueA better understanding of the relaxation phenomena in fabrics containing elastane yarns.