Model Simulation of Creep and Thermal Ratcheting of Engineering Polymers

Abstract

AbstractIn the present work, the creep response at specific temperatures and stress level of several polymers has been modeled by a viscoelastic model, analyzed in previous works. In particular, the experimental creep results under thermal cycling of polymers used in bolted flange connections, utilized as components of pressure vessel and piping are employed. The analysis is focused on the experimental results for polymeric flange materials like high density polyethylene and three types of gasket materials, namely poly‐tetrafluoroethylene PTFE (expanded e‐ and virgin v‐) and clickable nucleic acid. It has been proved that by the implementation of the model on a simple creep curve at a specific temperature, the model parameters could be evaluated. Hereafter, by imposing a thermal cycling process, two more parameters, associated with thermal ratcheting, could be acquired. It is found that the thermal ratcheting behavior exhibited by the employed materials, could be captured with a good accuracy. Given that the effect of thermal ratcheting on the long‐time performance of polymers in targeted applications is a crucial issue, the research findings in the present work are encouraging for the design of appropriate materials, and the prediction of thermal ratcheting.