中文摘要：

在不同应力水平下对经历不同老化时间的有机玻璃（PMMA）进行常温蠕变测试，分析物理老化和应力对材料蠕变柔量函数的影响，分析表明，老化时间对PMMA蠕变行为的影响满足流变简单性规律，即不同老化时间的蠕变柔量曲线可以沿对数时间轴平移而叠加到参考曲线上．取最长的老化时间为参考状态，依时间-老化时间等效原理，得到了各应力水平下的蠕变柔量主曲线，老化移位因子与老化时间在双对数坐标图上呈现线性关系，其负斜率就是老化移位率．结果表明，老化移位率随应力的增高而减小．

英文摘要：

The aging effect on creep behavior of PMMA was investigated by measuring creep compliance curves at four different stresses, 15 30 MPa with an interval of 5 MPa, for various aging times. It is shown that the creep compliance curves can be superimposed by horizontal shifting the creep response to the one at the reference aging time, indicating the rheological simplicity and the applicability of the timeaging time superposition principle. In this study the reference aging time was chosen as the age of the longest aged test, and the master curves for each stress level are created. The corresponding aging shift factor is found to be linearly proportional to the aging time in a double logarithmic plot, of which the minus slop is defined as the aging shift rate. It is also shown that the aging shift rate decreases with increasing stress.