Determination of Viscoelastic Response of Interphase Region in Carbon Fiber Reinforced Epoxy Using AFM Indentation

  • Libin K. BabuEmail author
  • Raman Singh
Conference paper
Part of the Conference Proceedings of the Society for Experimental Mechanics Series book series (CPSEMS)


The interphase region in fiber reinforced polymer (FRP) composites exhibits time dependent behavior due to the viscoelasticity of the matrix. AFM based (Atomic Force Microscopy) indentation utilizing different dwell periods for various constant loads are employed to analyze the creep behavior of the near–fiber region in carbon fiber reinforced epoxy. It is observed that along a radial line to the fiber, the relaxation of the polymer is lower closer to the fiber. Loading in the interphase region is known to be influenced by the fiber constraint effect. Therefore, 3D FE (Finite Element) simulations using an assumed non-linear elastic and linear viscoelastic behavior of epoxy is used to determine the extent of the influence of the fiber constraint on the viscoelastic response of the interphase region.


Carbon fiber reinforced composites Viscoelasticity Fiber constraint AFM indentation 



This material is based upon work supported by the National Science Foundation under Grant No. 1649481.


  1. 1.
    M.T. Shaw, W.J. MacKnight, Introduction to Polymer Viscoelasticity, 4th edn. (Wiley, New York, 2018)Google Scholar
  2. 2.
    H.F. Brinson, and L. C. Brinson, Polymer engineering science and viscoelasticity. New York, NY: Springer (2015)Google Scholar
  3. 3.
    J.A. Forrest, K. Dalnoki-Veress, J.R. Stevens, J.R. Dutcher, Effect of free surfaces on the glass transition temperature of thin polymer films. Phys. Rev. Lett. 77(10), 2002–2005 (1996)CrossRefGoogle Scholar
  4. 4.
    A. Hu, X. Li, A. Ajdari, B. Jiang, C. Burkhart, W. Chen, L.C. Brinson, Computational analysis of particle reinforced viscoelastic polymer nanocomposites—statistical study of representative volume element. J. Mech. Phys. Solids 114, 55–74 (2018)CrossRefGoogle Scholar
  5. 5.
    F.T. Fisher, L.C. Brinson, Viscoelastic interphases in polymer-matrix composites: theoretical models and finite-element analysis. Compos. Sci. Technol. 61(5), 731–748 (2001)CrossRefGoogle Scholar
  6. 6.
    J. Li, G.J. Weng, Effect of a viscoelastic interphase on the creep and stress/strain behavior of fiber—reinforced polymer matrix composites. Compos. B 27B, 589–598 (1996)CrossRefGoogle Scholar
  7. 7.
    G. Hochstetter, A. Jimenez, J.L. Loubet, Strain-rate effects on hardness of glassy polymers in the nanoscale range. Comparison between quasi-static and continuous stiffness measurements. J. Macromol. Sci. B 38(5-6), 681–692 (1999)CrossRefGoogle Scholar
  8. 8.
    G. Huang, B. Wang, H. Lu, Measurements of viscoelastic functions of polymers in the frequency-domain using nanoindentation. Mech. Time-Depend. Mater. 8(4), 345–364 (2004)CrossRefGoogle Scholar
  9. 9.
    C.C. White, M.R. Vanlandingham, P.L. Drzal, N.K. Chang, S.H. Chang, Viscoelastic characterization of polymers using instrumented indentation. II. Dynamic testing. J. Polym. Sci. B. Polym. Phys. 43(14), 1812–1824 (2005)CrossRefGoogle Scholar
  10. 10.
    S. Shimizu, T. Yanagimoto, M. Sakai, Pyramidal indentation load-depth curve of viscoelastic materials. J. Mater. Res. 14(10), 4075–4086 (1999)CrossRefGoogle Scholar
  11. 11.
    L.K. Babu, K. Mishra, R.P. Singh, Near–fiber effects of UV irradiation on the fiber–matrix interphase: a combined experimental and numerical investigation. Mater. Des. 157, 294–302 (2018)CrossRefGoogle Scholar

Copyright information

© Society for Experimental Mechanics, Inc. 2020

Authors and Affiliations

  1. 1.Department of Integrated Engineering Minnesota State UniversityMankatoUSA
  2. 2.School of Mechanical and Aerospace EngineeringOklahoma State UniversityTulsaUSA
  3. 3.School of Materials Science and EngineeringOklahoma State UniversityTulsaUSA

Personalised recommendations