Determination of nonlinear behavior of multi-walled carbon nanotube reinforced polymer: Experimental, numerical, and micromechanical

•Tensile and compressive properties of nanocomposites are determined.•Nanocomposite properties are determined experimentally.•A combination of micromechanical and numerical methods is used.•Two different approaches are taken to account for interface bonding.

In this investigation, nonlinear behavior of Multi Walled Carbon Nanotube reinforced epoxy resin is determined using experimental, numerical and micromechanical methods. Standard nanocomposite samples containing various weight fractions of MWCNTs were prepared and were tested. Experimental results show significant improvement in tensile and compressive mechanical properties of epoxy resin as a result of CNT addition. Compressive modulus of elasticity initially increased with nanotube content up to 0.45 wt.%. At higher CNT weight fractions, compressive modulus decreased slightly. In addition, Field Emission Scanning Electron Microscope was used to obtain images of the samples' fracture surface. These images suggested a good CNT dispersion in the matrix. Numerical simulations are conducted to evaluate the nanocomposite elastic moduli using two different interface models. Numerical results suggest that the connector model predicts values lower than the thin shell interface model. Also, the elastic-plastic behavior of nanocomposites was estimated using a combination of micromechanical and numerical methods. To achieve this goal, micromechanical methods based on Mori–Tanaka and Halpin–Tsai models were used to predict the tensile stress-strain curves for the nanocomposites. In addition, nanocomposite compressive behavior was predicted using a combination of numerical and micromechanical methods. Finally, the numerical and micromechanical results showed good agreement with experimental measurements.

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