The Flexing Fatigue Properties of Filled Rubbery Compounds under Constant and Variable Amplitude

Crack growth characteristics of rubbery materials are an important factor in determining their strength and durability. The present work studied three stocks composed of Natural Rubber (NR), Styrene Butadiene Rubber (SBR) and Polybutadiene Rubber (BRcis) filled with carbon black N330. Three percentages of (NR/SBR/BRcis) were studied, namely (40/60/0), (40/50/10) and (40/40/20) The intent was to develop the Standard Italian Perilli Recipe (SPR) for Truck Tires Sidewall manufactured in Al-Dewaniya Tires Factory (Iraq) that has (30NR/70SBR) filled with carbon black N550. The results of constant amplitude loading have confirmed the applicability of the Paris law to the flexing fatigue behaviour of truck tire sidewall components. The accumulative fatigue damage was studied by the application of Miner’s rule to variable amplitude loading and gave not conservative results for both sequences (L-H) and (H-L). The recipe that has (NR/SBR/BRcis) blending with percentages of (40/50/10) generally yielded the best in combined properties.