Title:
Theoretical and Experimental Considerations Regarding the Evaluation of the Mechanical Characteristics of Polyethylene Pipes Under Multiple Loading Conditions

Authors:
Ioana-Daniela Manu, Marius Gabriel Petrescu*, Ramadan Ibrahim Naim, Romania

Abstract:

Polyethylene pipes are used in most applications for the transport and distribution of drinking water. Pipe systems generally have complex routes that include undercrossings of roads. Consequently, the pipe loads are complex, resulting from: internal fluid pressure, soil loads, traffic pressure. In a test program aimed at evaluating both the axial stress behavior and the mechanical characteristics of polyethylene pipes used in the construction of water distribution piping systems, in the presence of defects, theoretical and experimental research was carried out. The main scope of the research carried out was to determine the behavior of PE100 polyethylene pipes under multiple stress conditions. Thus, a PE100 polyethylene pipe was successively analyzed in analytical evaluation, traffic overpressure simulation, internal pressure test and numerical evaluation. The purpose of performing the multiple stress test of the buried PE100 polyethylene pipe was to evaluate the influence of a defect that can occur on the outer surface of the pipe during installation in the trench, by simulating localized traffic overload and internal pressure, and determining the stress intensity factor, K_I. The present work represents a novelty and it is the main contribution in the buried PE pipe mechanical behavior field. The study addresses how the shape, position, and size of the surface defect could affect the value of the stress intensity factor. By modifying the values ​​of the geometric dimensions of the defect, obtained by imprinting on the outer surface of the pipe with outer diameter, D_e = 90 mm, wall thickness, s = 5.4 mm, and a length, L_pipe = 4000 mm, the viscoplastic character of the material was highlighted. The calculated value of stress intensity factor, K_I, is 0.7007 MPa·m^1/2, and calculated value of the maximum stress is 19.654 MPa. By numerical evaluation, the value of maximum stress developed in the pipe wall was obtained as 19.937 MPa.

DOI: http://dx.doi.org/10.51505/ijaemr.2025.1011