New evaluation method of angle tear property of vulcanizates

The combination method of numerical simulation and experimental verification was used to optimize the current evaluation method of tear strength of rubber unnicked angle test piece. Firstly, the tear energy at angle position of rubber test piece with different clamp distances was simulated by the simulation software, and then advanced video extensometer-digital image correlation analysis software was used to obtain the strain distribution cloud nephograms and the multi-location strain curves of the test piece with time. A new method was proposed to evaluate comprehensively the unnicked angle tear property by combining strain distribution cloud nephogram and corrected tear strength, and the method applicability was verified by the tear strength test of pure natural rubber and natural rubber/synthetic rubber blends. The results showed that the tensile degree of the non-effective test region and the tear energy at angle position were all different with the different clamp distances, when the other para-meters of the test piece were the same, which increased the volatility of the test results. Compared with the standard currently in effect, the variation coefficient of parallel test results could be reduced by using the corrected tear strength, and the test results was positively correlated with the carbon black dispersion in the vulcanizates.