Multiscale damage simulation of CFRP under low velocity impact

The present paper proposes an analysis method for precise prediction of the damage of the CFRP under the low velocity impact event. The method consists of multiple finite element analyses, those belong to two different scales: macro and micro scales, where macroscale corresponds to the 'specimen' scale and microscale corresponds to the 'crack' scale. In the macroscopic scale, the effect of the ply cracks are averaged and modelled by continuum damage mechanics. Delamination is modelled by cohesive element, and fibre damage is modelled by stress criterion and smeared crack model. Microscopic scale model is intended to simulate more precise damage evaluation. A representative unit cell (RUC) of the CFRP laminate is used a microscopic scale model. In the RUC, the individual ply crack is modelled by cohesive zone model, with delamination modelled by cohesive zone model. Deformation state observed in the each point of the macroscopic model was applied to the RUC for localization analysis, by using key DOF method. Intralaminar cohesive elements were degraded for reproducing matrix crack in the LVI simulation prior to the localization analysis. Matrix crack and delamination predicted by the analyses were qualitatively in good agreement with those in the impacted specimen observed by X-ray CT.