聚乙烯耐蠕变开裂的断裂力学实验方法与聚合物长时标开裂试验装置

Fracture Mechanics Test of Creep Cracking Resistance of PE and Test Facility for Polymer Long term Cracking Property

介绍了按断裂力学原理设计的实验方法及其数据处理要点，以及按断裂力学原理设计的聚合物长时标开裂试验装置和ＰＥＳＣ－１型高分子材料环境应力开裂速度测定仪的设计要点和参数，该仪器布置有１０个工作位，使用予制单边切口平板拉伸样条；用断裂力学参数——应力强度因子表征有裂纹样条的载荷；用光学显微镜追踪检测裂纹演化过程的细微变化并可拍照。可有目的地变化载荷和试验温度Ｔ，进行测试，初始应力强度因子Ｋ１０范围为０．０５～０．８ＭＰａｍ１／２，Ｔ为３０～１００℃，显微镜放大倍数为４×１０，１０×１０，２５×１０，由试验可测得试样的开裂诱导期ｔｉ和开裂速度ａ与试验条件下Ｋ１０、Ｔ的关系，以及与开裂行为有关的裂端细观特点，如裂端钝化、二次裂纹、银纹等。这些结果可全面地表征材料的耐蠕变开裂性能。

s A test based on fracture mechanics and principles for data processing are introduced.Test facilities for polymer long term cracking property,as well as the key design point and parameters of PESC-1 Polymer Environmental Stress Cracking Speed Tester,are also given.There are 10 working positions in the tester and test pieces are of single edge notched plate in tension.The load of specimen is characterized by stress intensity factor,and the cracking process is traced and photographed with a travelling microscope.The load and experimental temperature T could be changed intentionally.The initial stress intensity factor K 10 is 0.05～ 0.8 MPm 1/2 , T 30～100℃,optical magnification 4×10,10×10,25×10.The experimental results obtained included incubation time t i and cracking speed ,the relation of t i and with K 10 and T ,and the fine structures and phenomena at the crack tip,such as crack blunting,secondary cracking and crazing.All of these results could be used to characterize the creep cracking resistance of polymer materials in detail.