PE100燃气管材的非线性蠕变行为及其本构模型研究

对PE100燃气管材开展不同应力水平（2.4~9.6 MPa）下的常温蠕变测试，结果显示应力不超过5.4 MPa时，材料的蠕变柔量与应力水平无关，呈现出线性黏弹性行为，当应力高于5.4 MPa时，材料发生非线性黏弹性蠕变。基于单积分型非线性黏弹性本构理论，采用Findley模型对蠕变行为进行分析，并与Struik经验模型进行比较。结果表明，Findley模型和Struik模型均能较好地描述PE100管材的蠕变行为，但对高应力下的非线性蠕变行为，Findley模型比Struik模型描述得更准确。

Characterization and Constitutive Modelling of Nonlinear Creep of PE100 Grade Gas Pipe Material

Polyethylene （PE） has been widely used in pressure pipeline engineering due to its excellent corrosion resistance. Long-term service behavior of a pipe is predominated by the creep property of its raw material. It is of great significance to study the creep behavior of PE at room temperature for the safety and integrity evaluation of PE pressure pipelines. In this paper， the room temperature creep tests of PE100 grade gas pipe material were conducted under various stresses ranging from 2.4 MPa to 9.6 MPa. The results indicated that there was a stress independency of creep comp?liance of the material when the stress does not exceed 5.4 MPa， indicating linear viscoelastic behavior. However， a stress dependency occurred and showed nonlinear viscoelastic creep when the applied stress was higher than 5.4 MPa. Based on the single integral nonlinear viscoelastic constitutive theory， the Findley model was used to analyze the creep behavior of PE100 grade gas pipe material by comparison with the Struik empirical model. It was found that both the Findley model and the Struik model well described the creep behavior of the pipe material， but the Findley model was more accurate than the Struik one for modeling the nonlinear creep behavior under high stresses.