Life prediction of damaged polyethylene gas pipes

This paper deals with a new approach to life estimation of damaged thick-walled gas-pipes made of high-density polyethylene (PE-HD). The most common approaches to durability prediction of polyethylene gas-pipes rely on methods of fracture mechanics, which involve defining of a stress intensity factor experimentally. However, such tests are carried out on standardized specimens neglecting the influence of real pipe geometry and processing method. On the other hand these data are not always available to gas distributors, which are responsible for the durability of the installed pipelines. Therefore, we have been proposed a new approach aiming to obtain an empirical mathematical model for life prediction of polyethylene gas pipes on the basis of long-term experiments involving three parameters: pressure, length, and depth of initial notch type crack. The first results of the undergoing investigations on PE80 pipes will be reported in the paper.