In situ self-sensing of delamination initiation and growth in multi-directional laminates using carbon nanotube interleaves

Self-sensing capability of carbon nanotube buckypapers (BPs), played as in situ sensor on delamination damage in multi-directional laminates, was investigated in this paper. BPs were interleaved into these interfaces of the laminates, where delamination tends to happen firstly under tensile loading. The inserted BPs are porous and conductive, which can benefit infiltration of epoxy resin and give contribution to damage monitoring. Systematic analysis of resistance variation (ΔR/R0%) against strain has demonstrated that BPs are sensitive to the initiation and growth of delamination. When delamination initiates, a sudden rise of the ΔR/R0% or the slope of the ΔR/R0%-strain curves is observed and corresponding delamination initiation stresses are simultaneously obtained. Moreover, effect of thicker laminates on the sensitivity is also examined and the self-sensing ability of BPs has been further proved. Finally, tensile properties of the BPs interleaved laminates slightly change compared with these of base laminates.