J. Phys. Colloques
Volume 48, Numéro C8, Décembre 1987Fifth European Conference on Internal Friction and Ultrasonic Attenuation in Solids
|Page(s)||C8-3 - C8-13|
J. Phys. Colloques 48 (1987) C8-3-C8-13
STRESS RELAXATION IN SOLIDSJ. KUBÁT1 et M. RIGDAHL1, 2
1 Chalmers University of Technology, Department of Polymeric Materials, S-412 96 Gothenburg, Sweden
2 Swedish Pulp and Paper Research Institue, Paper Technology Department, Box 5604, S-114 86 Stockholm, Sweden
A cooperative model for stress relaxation is described. It is based on a two-level system where stimulated emission of phonons may occur and was formulated in order to circumvent some of the problems encountered with the theory of stress-dependent thermal activation. The cooperative model also provides some insight into the well-documented universal similarity in stress relaxation behaviour among different materials. The dynamic-mechanical response of the cooperative model is also analyzed in some detail. The experimental stress relaxation behaviour of composites based on high density polyethylene is described and it is suggested that the internal stress concept can be a valuable tool when trying to quantify the effect of fillers and surface treatments of fillers on the long-term mechanical properties of polymeric composites.