VISCOELASTIC TEMPERATURE DEPENDENT CHARACTERIZATION PROTOCOLS WITHOUT THE USE OF POISSON'S RATIOS

摘要

The previously formulated analytical and experimental protocols for a single temperature conditions in [1] are extended to multi temperatures in order to develop shift factors and master relaxation curves. The system consist of unidirectional tensile creep or relaxation experiments performed on viscoelastic specimen. A combination of a photogramet-ric device and a tensile testing machine provides stress data in the loaded direction and strains in both longitudinal and transverse directions. The data is integrated through the use of the integral constitutive relations, and produce values for the creep compliance parameters. Subsequently, the, viscoelastic Young ',s. shear and bulk moduli are determined without the use of viscoelastic Poisson's ratios (PR). Experimental results indicate strong time, temperature, stress and stress history dependencies of viscoelastic PRs.