Understanding on the creep behavior of fiber reinforced polymer via fiber/matrix interaction

• Published in: Construction & building materials Vol. 451; p. 138875
• Main Authors: Qin, Renyuan, Li, Yize, Wong, Soon Yee, Teo, Fang Yenn, Yu, Zechuan, Sun, Li, Zheng, Yu
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15-11-2024
• Subjects: Carbon fiber; Fiber reinforced composites; Glass fiber; Interfacial creep; Molecular dynamics simulations; Fiber reinforced composites; Interfacial creep; Molecular dynamics simulations; Glass fiber; Carbon fiber
• ISSN: 0950-0618
• DOI: 10.1016/j.conbuildmat.2024.138875

The interfacial interaction between fiber and matrix is believed as one of the key parameters that affects viscoelastic response of different types of fiber reinforced polymer (FRP) materials under constant loads, which origins from molecular level. Current experimental observations mostly attribute the differing viscoelastic responses of various FRPs to stress redistribution between fibers, while the differences in creep behaviors among various types of FRPs have not been well understood. Key factors in fiber/matrix interfacial interactions, such as the mobility of polymer chains, microstructural evolution at the interface, and the energy changes during the creep process in different FRP systems remain unclear. To comprehensively understand the interfacial creep behavior between fiber and matrix, this work investigates carbon fiber/epoxy and glass fiber/epoxy composites using molecular dynamics simulations. The study aims to elucidate the deterioration mechanism of the fiber/matrix interface under constant loads and highlight the differences in creep performance between carbon FRP and glass FRP. Results reveal that carbon FRP demonstrates a higher shear threshold stress under equivalent holding load conditions. Energy analysis and bond autocorrelation functions indicate higher non-bonded interactions and lower the creep migration rate of epoxy at carbon fiber/matrix interface. These findings offer insights into the molecular-level origins of interfacial creep behavior in composites, providing potential solutions to enhance the viscoelastic properties of FRP composites.
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•Interfacial threshold stress of CFRP is much higher than that of GFRP.•Sliding of chains is observed at epoxy/ graphite interface during creep.•Both sliding and stretching are observed at epoxy/silica interface during creep.•Significant free volume change is observed at epoxy/silica interface