Determination of the plastic behaviour of solid polymers at constant true strain rate

摘要: The methods of conventional tensile testing as applied to solid polymers are compared and reviewed critically. Experiments were performed using these techniques, it is shown that large variations in local strain rate occur while necking cold-drawing take place. A new method described which the samples tested atconstant true rate. This technique based on use a diameter transducer, an exponential voltage generator closed-loop machine. Flow curves for poly(vinyl chloride) high density polyethylene determined at room temperature over range 10−1 10−4 sec−1. It flow behaviour two can be approximated by constitutive relation:\(\sigma = K \cdot \exp [(\gamma _ \in /2) ^2 ] \dot ^m\), whereK andγ∈ constants andm, sensitivity, 0.02 0.06. concluded positive curvature log σ curve responsible stabilization localization associated with cold drawing, sensitivity plays much smaller role.