Uniaxial Strain Cyclic and Ratcheting Behavior of PE100 Pipe at Room Temperature

The uniaxial tension test, cyclic strain test under symmetric torsion and uniaxial ratcheting test were carried out for Polyethylene 100 (PE100) pipe at room temperature. The stress-strain responses of the PE100 pipe under different strain rates were discussed. The effects of cyclic strain amplitude, mean stress, stress amplitude and their loading histories on strain cyclic characteristics and ratcheting deformations of PE100 pipe were studied. The results show that PE100 is a kind of rate-dependent and cyclic softening material. Both strain cyclic characteristic and uniaxial ratcheting behavior were all strongly dependent not only on the current load condition, but also on the prior loading history. There was a threshold value to induce cyclic hardening for PE100 under symmetric torsion, namely 5% torsion strain amplitude. The former cyclic load larger than the threshold value induced cyclic hardening of PE100 under the following smaller load conditions. However such kind of hardening would vanish after standing for some time, indicating recovery ageing effect of PE100.