基于局部法高密度聚乙烯管道材料的断裂行为  

Fracture behaviors of high-density polyethylene pipe material based on local approah

作　　者：齐芳娟[1] 霍立兴[1] 张玉凤[1] 荆洪阳[1] 

机构地区：[1]天津大学材料科学与工程学院,天津300072

出　　处：《焊接学报》2003年第5期45-48,共4页Transactions of The China Welding Institution

基　　金：国家自然科学基金(50075061)

摘　　要：作者主要对低温下高密度聚乙烯(HDPE)管道材料的断裂参量进行了测试,并对三点弯试样进行了有限元数值计算,分析了低温下具有不同裂纹尺寸的三点弯试样裂纹尖端应力应变场。利用试验和有限元计算结果,基于局部法对HDPE材料的抗开裂行为进行了研究。结果表明,采用局部法可对具有不同原始裂纹长度三点弯试样之间的断裂行为进行相互预测,并且预测结果与试验结果吻合良好。一方面验证了表征材料脆性断裂特征的参量m和σ_u与初始裂纹长度无关,为一材料常数;另一方面也表明局部法能有效地描述HDPE材料的脆性断裂行为。对于HDPE管道材料,威布尔应力可以作为有效的断裂控制参量。High-density polyethylene (HDPE) plastic pipe is one of the important aims for the pipe industry presently. Study on its fracture behaviors is very significative. Crack opening displacement (COD) of HDPE pipe material was tested using three-point bend samples with different crack depth at -78°C. Finite element analysis (FEA) for HDPE three-point bend specimen with different crack length was conducted. The characteristic of stress-strain field near crack tip was studied. Based on the experimental results and finite element analysis, the resistance to initiation fracture of HDPE pipe materials was studied by the local approach. The results show that fracture behaviors of JJDPE three point bend specimens with different crack length at -78°C can be mutually predicted according to the local approach. The prediction results are in concordance with the test results. On one hand, the parameters m and au are material constant and independent crack length. On the other hand, the local approach can give a good description for the brittle fracture behaviors of HDPE pipe materials. For HDPE pipe material, the Weibull stress may be an effective fracture parameter.

关 键 词：高密度聚乙烯 断裂 有限元 局部法 威布尔应力 数值计算 管道 熔接 

分 类 号：TQ320.674[化学工程—合成树脂塑料工业] TB115[理学—数学]