engleski

3D Model for Numerical Prediction of Impact Induced Matrix Cracks and Delaminations in Layered Composite Shells

The numerical model for analysis of matrix cracks and delaminations in layered fibre composite shells has been presented. The model is extension from the similar one developed for composite plates. Four noded 3D element with reduced integration was applied in the discretization of the shell continuum. Impact loading was applied by defining mass and velocity of rigid impactor and appropriate contact surfaces between impactor and surface of the shell. The kinematics of the impact has been simulated using transient dynamic analysis. Using micromechanical Mori-Tanaka approach, mechanical properties of the laminate have been calculated utilizing the material constants of the fibre and the matrix. As the model is intended for numerical simulation of barely visible low velocity impact damage it is essential to evaluate matrix cracks by applying Hashin's matrix cracking criterion. Progressive failure is numerically modeled through degradation of mechanical properties at integration points. Kinematics of delaminating surfaces is numerically described through variable multi-point constraints. User subroutines have been implemented in ABAQUS for all specific numerical tasks and in the visualization of matrix cracks and delaminations.

layered composite shells; impact; delaminations; matrix cracks; micromechanics

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