Relationship between dynamic fatigue crack propagation properties and viscoelasticity of natural rubber/silicone rubber composites.

In this paper, dynamic fatigue crack propagation properties of natural rubber/silicone rubber (NR/VMQ) composites are studied under constant tearing energy ( G ) input. Through dynamic fatigue crack growth testing, it is found that with the increase of VMQ fraction, NR/VMQ exhibits a lower crack growth rate (d c /d N ). The viscoelastic parameters have been recorded in real-time during crack propagation, including the storage modulus E ', loss factor tan  δ , and loss compliance modulus J '', and their relationships with crack propagation behaviour have been established. The improved crack propagation resistance is attributed to the reduced J '', resulting from the synergistic effect of increased E ' and decreased tan  δ , and thus more energy dissipation occurred in the linear viscoelastic region in front of the crack tip, which consumed part of the energy for crack growth. Finally, good correlation between d c /d N and J '' could be successfully established.