A quantitative investigation on vibration durability of viscoelastic relaxation in bolted composite joints

Z. Zhang, Y. Xiao, Y. Q. Liu, Zhongqing Su

Research output: Journal article publicationJournal articleAcademic researchpeer-review

20 Citations (Scopus)


Time-dependent behavior and factors affecting preload relaxation in a carbon/epoxy composite bolted joint under resonance were studied. The effect of viscoelasticity of composite material on bolt relaxation was studied quantitatively through modal analysis from the perspective of energy dissipation and stiffness degradation. Damping ratio and resonance frequency were utilized to characterize the effects of preload relaxation on structural dynamic response. The loss of preload was found to decrease with increasing initial preloads over a 10 h vibration fatigue. However, an increase in preload loss occurred as exciting frequency increases. Vibration fatigue damage was found to result in decaying stiffness and amplitude responses of the bolted joints, along with an increase in damping ratio. As a proof-of-concept study, a beam-like specimens with and without bolted joints were comparatively excited to ascertain their respective dynamic responses; results revealed that relaxation in bolted joints could be attributed to the conjunct mechanisms between viscoelastic behavior of polymer matrix composites and interface friction for different contact surfaces, where such relaxation behavior was mainly due to viscoelasticity of the joint materials.
Original languageEnglish
Pages (from-to)4041-4056
Number of pages16
JournalJournal of Composite Materials
Issue number29
Publication statusPublished - 1 Dec 2016


  • bolted joints
  • Composite structures
  • damping ratio
  • long-term durability
  • preload relaxation
  • vibration fatigue

ASJC Scopus subject areas

  • Ceramics and Composites
  • Mechanics of Materials
  • Mechanical Engineering
  • Materials Chemistry

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