Insights on the J‐integral expression of pure shear carbon black filled natural rubber specimen and predicting the crack growth rate using finite element method

Abstract The J‐integral approach manifests itself in an efficient way to determine the crack growth and failure mechanism of tread and sidewall compounds used in tyres. Therefore, for a pure shear (PS) specimen of carbon black filled natural rubber, the J‐integral formula was vivisected, and the material parameters were defined using the concepts of solid mechanics considering the planar stress conditions. Theoretical calculations, experimental observations, and finite element analysis were executed to calculate the J value for different strain percentages. Different hyperelastic material models were used to understand the hyperelastic behavior of the test compound, but Yeoh model was found to be the best fit with the least error against the experimental test data. The frequency sweep dynamic mechanical analyzer test was done to observe the viscoelastic response of the material. It was observed that the J value decreased with decreasing contour radius and had exhibited stark difference with the global tearing energy values, indicating the effects of stress softening and the dependence of J value on the elastic characteristics of the material. Further, the J value attained from finite element methods for a random strain 22% was used to predict the crack growth rate of the pre‐notched PS specimen. Highlights J‐integral formula for pure shear specimen using solid mechanics approach. J value comparison of theoretical, experimental, and finite element methods. Dependence of J value on the elastic characteristics of the material. Different hyperelastic models compared and Yeoh model chosen for analysis. Prediction of crack growth rate at a random strain percentage.