Crack Propagation in a Strain-Crystallizing Elastomer

Abstract

The dependence of small‐scale crack propagation in a strain‐crystallizing elastomer (natural rubber) upon the applied strain has been studied under conditions of cyclic deformation over a range of frequencies. During each cycle the crack propagates along a well‐defined path, different from the axis of symmetry, which is identified as the locus of maximum stress in a stationary stress distribution (i.e., one which does not move with small advances of the crack). The stationary stress hypothesis also accounts for the quantitative dependence of crack growth upon the external constraint. It is shown that a stationary stress distribution could arise as a result of the severe mechanical hysteresis displayed by strain‐crystallizing rubbers.