Jinling Gao (1), Nesredin Kedir (2), Cody D. Kirk (1), Julio A. Hernandez (1), Junyu Wang (1), Shane Paulson (1), Xuedong Zhai (1), Todd Horn (3), Garam Kim (3), Kamel Fezzaa (4), Francesco De Carlo (4), Pavel D. Shevchenko (4), Tyler N. Tallman (1), Ronald Sterkenburg (3), Weinong Chen (1,2)
Composites Science and Technology, 210, July 2021. DOI: 10.1016/j.compscitech.2021.108814

Keywords

Cross-ply GFRCs; Microscale damage mechanism; High-speed X-ray PCI; Dynamic loading; Digital imaging correlation

Abstract

We integrated the high-speed synchrotron X-ray phase-contrast imaging (PCI) with a modified Kolsky compression bar loading platform to visualize the dynamic failure processes of cross-ply glass fiber reinforced composites (GFRCs). Four S-2 glass/SC-15 composite specimens were prepared, having similar thicknesses but different stacking sequences, namely as [012/9012], [9012/012], [08/908/08], and [908/08/908]. Three-dimensional synchrotron X-ray computed tomography and scanning electron microscopy (SEM) were employed to examine the microstructures and quantify the fiber volume fractions. Each specimen was notched and subjected to a dynamic three-point flexural loading. The onset of cracking close to the notch tip, crack propagation in 0° or 90° plies and their interface, crack opening, and ultimately failure of the specimen were captured by high-speed synchrotron X-ray PCI. Additional dynamic experiments were performed to determine the average time when the stress wave propagated through the specimen and correlate the X-ray images with the specimen's force-deflection response. Finally, the surface morphology of each specimen after the dynamic loading was imaged by SEM. Comparison between real-time X-ray images and post-fracture SEM images demonstrated the capability of the X-ray method to record damage evolution inside composites. Furthermore, the high spatial and temporal resolutions of the X-ray setup and edge enhancement by PCI enabled the identification of microscale damage features within 1 μs. Two damaging processes were identified, crack growth was quantified, and fracture toughness of the composites was evaluated. The method is deemed useful to reveal microscale damage mechanisms and track cracking behaviors inside cross-ply GFRCs under dynamic loading in real time.

How Our Software Was Used

Dragonfly was used for 3D reconstruction.

Author Affiliation

(1) School of Aeronautics and Astronautics, Purdue University, 701 W Stadium Avenue, West Lafayette, IN, 47907, USA.
(2) School of Materials Engineering, Purdue University, 701 W Stadium Avenue, West Lafayette, IN, 47907, USA.
(3) Indiana Manufacturing Institute, Purdue University, 1105 Challenger Avenue, West Lafayette, IN, 47906, USA.
(4) Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439, USA.