Reynolds professor and head, N.C. State University, Raleigh, N.C.
Project engineer, Hanes Corporation, Winston-Salem, N.C.
Pages: 17 Published: Jan 1979
Reported are the results of an experimental and theoretical investigation of the dynamic viscoelastic properties of twisted continuous filament yarn subject to low frequency longitudinal excitation superimposed on high initial strain. The object is to relate the effective dynamic mechanical properties of the constituent filaments and the geometry of the filaments in the structure. An analytical model is presented which defines this relationship based on the following principle assumptions: (1) the imposed dynamic longitudinal strain is propagated as a plane wave in the twisted yam structure, (2) filament locations within the yarn structure are constant radius helical paths, and (3) filament dynamic mechanical properties can be represented by a generalized Maxwell model. An analysis of the effects of filament to filament interactions within the yarn structure represented by a simple coulomb friction is also included in the model development. Experiments performed on 70 denier, 34 filament nylon 66 yarn using the Rheovibron DDV II Viscoelastometer shown that yarn dynamic mechanical properties are predictable in terms of the dynamic mechanical properties of the filaments and the geometry of the yarn structure using the developed model at levels where sufficient static strain is imposed to eliminate coulomb friction effects.
dynamic moduli, viscoelastic properties, nondestructive testing, yarn properties, wave propagation, yarn modeling
Paper ID: STP36951S