Numerical Analysis of Fracture Mechanics of SENB Specimens Prepared From HDPE Pipes

High density polyethylene (HDPE) is commonly used in pipe fabrication for water and natural gas systems, due to its versatility, low cost and lightweight. A piping system is subject to service conditions such as impact and cyclic loads as a consequence of internal pressure or external pressure fluctuations, and the existence of discontinuities in the material. These conditions cause material damage, cracking and weakening, and have to be considered in the piping design. The Boundary Element Method (BEM) is a numerical method based on integral equations that consider only the contour of the solid (meaning an easier meshing). Crack modeling is one of the most important applications for the BEM, since it allows an accurate stress analysis around the crack tip. In this work, a computational study based on the BEM in two dimensions whose aim is to determine the stress intensity factors (SIFs) in order to evaluate the mechanical resistance to fracture of HDPE PE100 pipes and its comparison with the results obtained by previous experimental tests, is developed. Numerical simulations of specimens subject to three point bending loads (SENB specimens) using the characteristics of the linear elastic fracture mechanic (LEFM), are developed. As a first attempt, the numerical models of different SENB geometries are validated comparing the numerical solution versus the results given by a reference solution from literature. The results show that the BEM under the LEFM approach is valid for loads within the linear range of HDPE since LEFM gives an upper bound of the fracture load of HDPE specimens; however, an Elastic-Plastic fracture analysis could be required for loads in the plastic range of the material.