Relaxation and Inverse Relaxation of Yarns After Dynamic Loading

During weaving, warp yams are subjected to dynamic loading before stress relaxation during a loom stop. A test method is presented for simulating this behavior. There are three types of relaxation curves—simple relaxation, inverse relaxation, and mixed relaxation—depending on the previous load history of the yam. One can calculate the residual force at infinite time in a relaxation test from a model for the tensile curve of spun yams. There seems to be good correlation with the results of tests made using this method.