Uniaxial ratchetting behavior of vulcanized natural rubber

Most of rubber engineering components endure cyclic loading during their service, and a nonzero mean stress during cyclic loading may cause an accumulation of strain which is known as ratchetting phenomenon. In order to study the ratcheting effect of rubber, a series of uniaxial ratchetting experiments were conducted on vulcanized natural rubber (NR). The effects of cyclic stress amplitude, mean stress and their histories on ratchetting behavior were studied, respectively. The uniaxial ratchetting behavior of natural rubber depends greatly on the stress amplitude and mean stress. The ratchetting strain rate greatly increases with the stress amplitude or mean stress increased. Experimental results reveal that the rubber material exhibits a strong memory of the previous high loading history, and such memory plays a significant role on the subsequent ratchetting. The ratchetting behaviors of the rubber exhibit little sensitive to the applied cyclic stress rate except for the initial strain. POLYM. ENG. SCI., 48:191–197, 2008.