Local elongation of stretched filled rubber surface

Local elongation of the surface of a stretched rubber is estimated by comparing the stiffness of stretched filled (30 or 50 phr of silicica) styrene-butadiene vulcanizate and the results of finite element simulation of the indentation of the unfilled elastomer. The local strain exceeds the macroscopic value, yet the weakly loaded areas are also present. As the macroscopic elongation increases, the oriented polymer strands are formed, whose strain is particularly high. An increase in the filler content significantly increases the number and local elongation of strands. The highest tensile loads of the filled matrix occur in the gaps with the initial size of 100 nm. The limitations of the dynamic indentation of stretched elastomers are shown.