Crack velocities in natural rubber

Abstract

Measurements are reported of the limiting velocity of a running crack in biaxially stretched sheets of unfilled and carbon-black-filled natural rubber. The crack velocity was found to increase with the cleavage strain, ey, and also with the strain, ex, parallel to the direction of tearing, reaching values of over 100 m sec-1 at the highest strain levels employed. These crack velocities are shown to be close to those predicted by Mott's theory, i.e., about one-third of the velocity of sound, when a strong strain-dependence is recognized for the velocity of sound in rubber. © 1982 Chapman and Hall Ltd.