Long-Term Performance Assessment of Profiled Polypropylene Pipes: Experimental Testing versus Nonlinear Finite Element Analysis

This study examines the mechanical behavior and properties of a 36-in. diameter double-wall polypropylene (PP) pipe using experimental testing and nonlinear finite element analysis (FEA). The pipes were evaluated according to the relevant ASTM and AASHTO standards. Specimens from the double-wall pipes were prepared following ASTM D638, and tensile creep tests were conducted at five load levels, in compliance with ASTM D2990-09, for a duration of 1,000 h. Additionally, parallel plate tests were performed on three 42-in.-long pipe samples according to ASTM D2412-11 and AASHTO M330-13 to assess stiffness and load-deflection characteristics. Nonlinear FEA of both experiment types was carried out, and the time-dependent properties of PP were successfully captured. Validation of the FEA with the performed experiments enabled the determination of Prony series coefficients, facilitating accurate modeling of the relaxation behavior in PP materials for further investigation.