Numerical reconstruction of graphite/epoxy composite microstructure based on sub-micron resolution X-ray computed tomography

This study presents a combined experimental and computational effort aimed at high-resolution 3D imaging, visualization, and numerical reconstruction of a fiber-reinforced polymer (FRP) composite microstructure at the constituent-level length scale. A unidirectional sample of graphite/epoxy composite is imaged at sub-micron resolution using a 3D X-ray computed tomography microscope. The numerical reconstruction is enabled by a novel segmentation algorithm, which is developed using concepts adopted from computer vision and multi-target tracking, to detect and estimate with high accuracy the position of individual fibers in a volume of the imaged composite. Results from the segmentation algorithm are compared qualitatively to the tomographic data and suggest high accuracy of the numerical reconstruction. The segmentation data are also used to quantify the relative distribution of fibers within the imaged cross sections of the volume and the local fiber misorientation relative to the global fiber axis. Finally, the segmentation data are converted into a solid model of fibers and surrounding resin, which is then meshed using commercially available finite element (FE) software. A static, linear elastic simulation is performed on NASA's Pleiades supercomputer to quantify the computational cost associated with the high-fidelity, constituent-level, 3D numerical model. The high-fidelity simulation is an important step towards demonstrating the feasibility of an FE-based simulation framework for FRP composites at the constituent length scale. (C) 2014 Elsevier Ltd. All rights reserved.