摘要
在室温下对HDPE材料进行控制位移的实验 ,结果表明 :在加载条件下进行应力松弛 ,应力随时间的增长而减小 ;而卸载条件下的应力松弛过程中 ,若反向应变较小 ,则应力随时间而减小 ,当反向应变较大时 ,应力随时间而增加 .这种现象不能用非线性弹性理论进行解释 .运用Krempl提出的过应力模型对聚合物在加卸载条件下的应力松弛行为进行了合理的解释 .
Displacement controlled experiments on HDPE (high density polythylene) at room temperature suggest that in the case for relaxation test without strain reversal , the value of stress continues to decrease with increasing time and tends to gradually approach a stable value; in contrast, when the magnitude of strain reversal is small, the value of stress tends to decrease with time, but when the magnitude of strain reversal is large, a curious behavior is observed, in which the value of stress increases continously with time until it approaches a stable value asymptotically. The anomolous results observed in the case for relaxation test with strain reversal can t be explained by nonlinear elasticity. In this paper, an overstress model proposed by Krempl is adopted to study the stress relaxation behavior of polymers. It shows that the overstress concept can easily explain these anomalous results occurred in polymers in the case for relaxation test with strain reversal.
出处
《湘潭大学自然科学学报》
CAS
CSCD
2001年第1期37-40,共4页
Natural Science Journal of Xiangtan University
基金
国家自然科学基金!资助项目 (196 32 0 32 )
湖南省教委高等学校科研项目! (99C12 2 )
