Effect of Nano-Sio₂ on The Creep Behavior of Carbon Fiber/Polyester Composites for Oil Pipelines

The study focuses on enhancing the creep resistance of composite pipes made from carbon fiber, which contains 55% polyester and is reinforced with nano silicon dioxide nanoparticles for use in oil pipeline applications. The research investigates how varying the weight percentage of nanoparticles (0.16%, 0.2%, and 0.24%) affects the mechanical properties and creep behavior of the composite material. The results reveal that incorporating nanoparticles significantly improves creep resistance. Specifically, creep strain decreased by 21% as the nanoparticle ratio increased from 0.16% to 0.2%, and by 35% when the ratio increased to 0.24%. The results of the scanning electron microscope (SEM) analysis indicated a uniform distribution of nanoparticles at concentrations of 0.2% and 0.16%. However, at a nanoparticle weight of 0.24%, a small percentage of agglomerates was observed, leading to a lower improvement in creep strain resistance compared to the 0.2% concentration. The study utilized numerical analysis through the finite element method, employing ANSYS software to simulate the creep behavior of composite pipes over a period of eight years under a constant internal pressure of 6.8948 MPa. It was found that stresses and strains were concentrated at the connection points near the pipe ends, underscoring the importance of periodic inspections in these critical areas. Additionally, the constants from Norton's equation at constant temperature were extracted to predict the long-term creep behavior of the composite material. The results provide design guidelines for improving the long term reliability of composite pipelines in oil transport systems.