Mode-I pullout model of nanofibers with surface effects

•Mode-I pullout model for nanofibers with surface stresses and surface elasticity.•Influence of surface effects on the crack bridging mechanism of nanofibers.•Parametric study on the effects of volume fraction, aspect ratio, and aggregation.

A mode-I pullout model is proposed to investigate the bridging mechanism of nanofibers in composites. Surface effects are characterized in terms of surface tension and surface elasticity by using the theory of surface elasticity. Our analysis shows that surface effects may either enhance or impede the bridging effect, depending on the residual surface stress and surface moduli. The effects of volume fraction, aspect ratio, and aggregation of nanofibers are also examined. It is found that the aspect ratio and aggregation have significant influences on the bridging force while the effect of volume fraction is relatively small.

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