疲劳/蠕变复合作用下聚碳酸酯的交互损伤研究

Study of the mutual damage of polycarbonte both in fatigue and creep

探讨了在疲劳/蠕变复合作用下聚碳酸酯的损伤交互作用。结果表明,在疲劳/蠕变复合作用下聚碳酸酯存在疲劳和蠕变的交互损伤,其断裂寿命比纯疲劳或纯蠕变的断裂寿命低;断裂机制是由于疲劳循环载荷周期变化导致分子链和链段伸长/收缩往复运动,使在蠕变单向外力作用中受阻的分子链和链段松动和活化,从而促进蠕变运动和断裂。并且,疲劳/蠕变的交互损伤程度与温度密切相关。聚碳酸酯在较低温度的疲劳/蠕变交互损伤作用大于较高温度的交互损伤作用。随温度升高,疲劳/蠕变断裂寿命下降是疲劳和蠕变各自的单独损伤增加所致。

The mutual damage of polycarbonte both in fatigue and creep were studied. The results show that the mutual damage of polycarbonte existed both in fatigue and creep. The fracture life appeared less than any one of pure fatigue or creep. The fracture mechanism is that fatigue cycle load causes molecular chains or chain segments to be elongated and shortened cyclically ;and then the molecular chains or chain segments which movements were resisted in single directional external force are loosened and activated.Therefore it encourages creep movement and fracture. The degree of mutual damages both in fatigue and creep is closely related to temperature. The degree of mutual damages at lower temperature is greater than that at higher temperature.The fracture life is shorter at higher temperature because the individual damage of pure fatigue or creep increases.