Prediction of stress relaxation of fabrics with increased elasticity

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.