非线性粘弹体的时间-温度-应力等效原理及其应用

考虑粘弹性材料特征时间的应力相关性，认为应力水平与温度、压力、溶剂浓度、损伤及老化等材料特征时间的影响相似，有其等效性。依自由体积理论，推导了温度－应力移位因子的表达式，提出了时间－温度－应力等 效原理。应用此原理，可以将不同温度和应力水平下的儒变曲线移位成某一参考温度和参考应力水平下的主曲线，从而可以通过较高温度和应力水平下的短期蠕变行为来预测较低温度和应力水平下的较长期的蠕变行为。实例分析了高密度聚乙烯（HDPE）非线性蠕变行为的－应力等效性。

TIME-TEMPERATURE-STRESS EQUIVALENCE AND ITS APPLICATION TO NONLINEAR VISCOELASTIC MATERIALS

Stress dependence of the characteristic time of viscoelastic materials was investigated. The influence of stress level on the characteristic time is considered to be similar to those of temperature, pressure, solvent concentration, damage and physical aging. The time temperature stress equivalence principle is presented. By using the equivalence principle, the creep curves under different temperature and stress levels can be shifted into a master curve at reference temperature and stress state. Thus the long-term creep behavior of viscoelastic materials under lower temperature and stress can be predicted from the short term one under higher temperature and stress. As an example, the nonlinear creep behavior of high density polyethylene (HDPE) under room temperature was studied using the presented time stress equivalence principle.