抄録
This study evaluates the effect of fillers on the crack growth behavior of natural rubber. Rubber strip specimens containing various amounts of carbon black and silica are used to observe crack propagation behavior. Images around a propagating crack are recorded using a high-speed camera. Then, not only the crack growth rate but the strains near the crack are obtained from the consecutive images. A digital image correlation technique is used for measuring strains from images. The fillers on the fractured surfaces are observed using a scanning electron microscope. From the experimental results, it is found that the crack propagates to failure except for the specimens with high filler contents. The results suggest that the energy dissipation process at the crack tip varies depending on the filler. It is also found that the use of carbon black and silica as fillers together inhibit crack growth. The results of the strain measurement show that the specimens with faster crack growth rate have larger strains in the vicinity of the crack. The results also show that the strain increase and decrease repeatedly at the crack tip during the acceleration and deceleration of the crack growth rate. The effect of energy dissipation on crack growth is also evaluated by temperature measurements using thermography. It is found that the temperature increase occurs in the crack vicinity during the crack deceleration process. The results indicate that energy dissipation contributes to the deceleration of crack growth.
