Modeling the effect of a soft interlayer on the stress distribution around fibers: Longitudinal and transverse loading

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10 Citations (Scopus)


A model is presented which describes the effect of a soft interlayer with changing properties on the stress distribution around a fiber embedded into an infinite matrix. Transverse loading induces large deformations in the interlayer compared to the matrix and if the interphase is very soft mainly compressive deformations occur in it. Radial stress decreases considerably in this case and the stress maximum shifts to the surface of the fiber. However, stress concentration depends also on the stiffness of the interphase, increased stress concentrations may develop in the presence of interlayers having only slightly lower stiffness than the matrix. In parallel loading, deformations and shear stresses decrease in the presence of the soft interphase, the entire deformation is concentrated into a very narrow layer. Both shear yielding and debonding can take place in transverse loading, the dominating mechanism depends mainly on the properties of the interlayer. Very soft interlayers promote shear yielding. In parallel loading such interlayers result in low pull-out forces, load transfer is impossible. Although the presence of a soft interlayer favorably changes stress concentration around the fiber, as expected, it is deleterious for reinforcement and stress transfer. The results clearly explain why soft interlayers are not employed in practice in spite of their apparent advantages.

Original languageEnglish
Pages (from-to)139-148
Number of pages10
JournalMacromolecular Materials and Engineering
Issue number2
Publication statusPublished - Feb 18 2002



  • Debonding
  • Fiber reinforcement
  • Soft interlayer
  • Stress analysis
  • Yielding

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry

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