DID YOU KNOW? DTIC has over 3.5 million final reports on DoD funded research, development, test, and evaluation activities available to our registered users. Click

HERE to register or log in.

# Accession Number:

## AD0626208

# Title:

## NONLINEAR RUBBERLIKE VISCOELASTICITY: A MOLECULAR APPROACH.

# Descriptive Note:

## Rept. for Mar 64-Mar 65,

# Corporate Author:

## AIR FORCE MATERIALS LAB WRIGHT-PATTERSON AFB OHIO

# Report Date:

## 1965-10-01

# Pagination or Media Count:

##
28.0

# 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 Taylors 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 Boltzmanns 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

# Distribution Statement:

## APPROVED FOR PUBLIC RELEASE

#