Analysis of time-dependent deformation of a CFRP mirror under hot and humid conditions

Yoshihiko Arao*, Jun Koyanagi, Shin Utsunomiya, Shin Ichi Takeda, Hiroyuki Kawada

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


The long-term micro-dimensional stability of a carbon fiber reinforced plastic (CFRP) mirror was investigated in terms of creep deformation, moisture swelling and self-shrinkage. A 4-point bending creep test was carried out using specimens made from pitch-based high-modulus CFRP laminates to obtain a creep constant based on linear viscoelasticity, and we then investigated the weight change and geometrical change during a moisture absorption test using a CFRP specimen. The anisotropic diffusivities and coefficients of moisture expansion (CMEs) in CFRP laminates were obtained by fitting analytical data into the experimental data. Finally, the shrinkage behavior caused by physical aging of the polymeric material was examined using a fiber Bragg grating (FBG) sensor embedded in the neat resin specimen. Applying these results, we analyzed the geometrical changes in a CFRP mirror that resulted from time-dependent deformation by the mirror's weight, moisture absorption and physical aging, respectively. We discuss which factor is dominant in the deformation of CFRP mirrors under various conditions.

Original languageEnglish
Pages (from-to)183-197
Number of pages15
JournalMechanics of Time-Dependent Materials
Issue number2
Publication statusPublished - 2009 May


  • CFRP mirror
  • Creep
  • Dimensional stability
  • Moisture absorption
  • Physical aging

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Materials Science(all)
  • Aerospace Engineering
  • Mechanical Engineering


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