01782nas a2200169   4500008004100000022001400041245006700055210006700122260000800189300001100197490000600208520123700214100001901451700002701470700002001497856009501517       2018                        eng d  a2475-995300aModeling the universal viscoelastic response of polymer fibers0 aModeling the universal viscoelastic response of polymer fibers  cJUN  a0626010 v23 a<p>Polymer fibers, including natural silk and synthetic fibers, exhibit universal viscoelastic response. On stretching below yield, they show logarithmic stress decay. On unloading fibers with a glassy amorphous phase, the stress recovers. A simple phenomenological model accurately describes data from independent mechanical experiments and provides insights into the micro structural origins of the fiber response. Counter to intuition, the model indicates that it is the crystalline regions, rather than the amorphous glass, that deform first on stretching fibers at high strain rates. On holding a stretched fiber, stress decays as a consequence of relaxations in amorphous regions. Finally, unloading the fiber transfers stress from the amorphous to crystalline regions resulting in stress recovery. Model parameters correlate well with the fiber microstructure. Crystal and amorphous moduli from the model match those from x-ray diffraction. Activation energies for the temperature dependence of the peak relaxation time are similar to those reported in the literature. Thus, a simple model that invokes only crystal-amorphous coexistence can successfully model the mechanical response of a wide variety of polymer fibers.</p>1 aSharma, Aakash1 aKumaraswamy, Guruswamy1 aThakre, Shirish  uhttps://library.ncl.res.in/content/modeling-universal-viscoelastic-response-polymer-fibers