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Material response and reversible cracks in viscoelastic polymers
Author(s) -
Wool Richard P.
Publication year - 1978
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760181404
Subject(s) - viscoelasticity , materials science , dissipation , composite material , polymer , work (physics) , energy balance , constitutive equation , polypropylene , mechanics , thermodynamics , finite element method , physics
Deformation processes in viscoelastic polymers are examined in terms of an energy balance involving work, strain energy, viscous dissipation and damage. The concepts of time dependent damage and reversible cracks are presented. The latter, while giving rise to novel mechanical behavior in viscoelastic materials, are important considerations in temperature dependent recovery phenomena of deformed polymers. Constitutive equations are derived for systems with reversible cracks analogous to Maxwell and Kelvin viscoelasticity models. Retractive forces arising from crack closure occur by conversion of surface energies to strain energy and subsequently to mechanical work. This effect is investigated during contraction of hard‐elastic polypropylene fibers under constant load at different temperatures.