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

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.In this paper,crack opening displacement (COD) of HDPE pipe material was tested using three-point bend samples with different crack depth at -78℃.Finite element analysis (FEA) forHDPE 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 HDPE three pointbend specimens with different crack length at -78℃ can be mutually predicted according to the local approach.The prediction results are in con-cordance with the test results.On one hand,the parameters m and σ_u arematerial 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 maybe an effective fracture parameter.