Low velocity impact simulation of CFRP laminates considering microscopic damage interaction

This study is intended to be the basis for developing more advanced strategy of finite element (FE) modeling for low velocity impact (LVI) simulation. In this study, the induction of delamination by matrix crack was numerically observed by microscopic analysis of a representative unit cell (RUC) model. The RUC model implements intralaminar and interlaminar cohesive elements for describing matrix crack and delamination, respectively. The induction under various situations were appropriately observed by localization analyses; implement periodic boundary conditions on the RUC model, and apply macroscopic strain and curvature predicted by LVI simulation. Periodic boundary conditions were formulated based on the “key degrees of freedom” method in order to apply macroscopic quantities to the RUC model efficiently. 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. Therefore, it can be expected that the interaction between matrix crack and delamination will be derived numerically.