NONLINEAR RUBBERLIKE VISCOELASTICITY: A MOLECULAR APPROACH.
Abstract
The paper presents a treatment of the large nonlinear ddeformational response of amorphous elastomeric materials. In the development presented the difference between the dynamic and equilibrium tension in a macromolecular chain is expressed as a 'functional'. The functional is expanded in a series analogous to Taylor's series and higher terms are neglected to obtain a linear integral equation for the viscously retarded d response of the network chain. The equation obtained corresponds to a generalized one-dimensional version of Boltzmann's superposition equation on the macroscopic scale. It is then shown that the time dependent response of the molecular chain is independent of the magnitude of the deformation and, consequently, is of the same analytical form whether the deformation is infinitesimal or finite. From this it necessarily follows that there cannot be an inconsistency at finite stress and strain which is not allowed at infinitesimal excitations. Thus the response at finite excitations can be treated generally by employing the 'generalized' superposition equation and the same techniques which have been utilized in the linear theories. By employing the usual kinetic theoeeory assumptions, equations are developed for the macroscopic response of a well vulcanized rubber. Experimental data obtained in creep, stress relaxation, and dynamic stress-strain for three different elastomers are presented which support the approach outlined. Some consequences of the theory are discussed. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1965
- Accession Number
- AD0626208
Entities
People
- John C. Halpin
Organizations
- Air Force Research Laboratory