Dynamic fracture of C/SiC composites under high strain-rate loading: microstructures and mechanisms

Abstract

We investigate dynamic fracture of C/SiC composites under high strain-rate compression or tension with split Hopkinson pressure bar (SHPB) and gas gun loading. Components of the as-fabricated composites are mapped and quantified with X-ray computed tomography, including C fibers and fiber bundles, SiC matrix, and inter-and intrabundle voids. Compression loading is applied along the out-of-and in-plane directions by SPHB at strain rates of 10 2 − 10 3 s −1 along with in situ X-ray phase contrast imaging. Out-of-plane direction compression and tension are examined with gas gun impact at strain rates 10 4 − 10 5 s −1. For the out-of-plane loading, compression induces fracture via void collapse and shear damage banding, while delamination dominates fracture for the in-plane direction compression. With increasing strain rates, the compression failure modes transit from interbundle to intrabundle fracture of SiC, and then to fiber and bundle breaking. Tensile failure involves delamina

Dynamic in-situ imaging of methane hydrate formation and self-preservation in porous media

“…Recent instrument developments (Mokso et al, 2017) allow to capture processes with sub-second temporal resolution. Important applications of fast imaging include multi-phase fluid flow in porous rocks (Youssef et al, 2013;Blunt et al, 2013;Fusseis et al, 2014a), deformation and geomechanical testing of samples (Baker et al, 2012;Li et al, 2015;Wang et al, 2016), and hydraulic fracturing (Kiss et al, 2015).…”

Experimental Methods for Characterizing Dynamic Response of Soft Materials

“…To understand the dynamic damage process more accurately, real-time damage visualization methods are desired. Recently, Kolsky bars have been integrated with high-speed, high-resolution X-ray phase contract imaging (PCI) and X-ray diffraction (XRD) methods to realize this desired capability [16][17][18][19][20][21]. The high-speed X-ray PCI and XRD can also be used simultaneously to reveal the dynamic deformation and damage processes from different angles at different length scales in a single dynamic experiment [19].…”

“…Modifications are necessary to the Kolsky bars to ensure the achievement of desired testing conditions on the specimens for accurate results. Also, recent integration of high-speed X-ray visualization techniques with the classical Kolsky bar dynamic loading methods opens up new potentials for better understanding of dynamic behavior of materials [16][17][18][19][20][21]. Besides the X-ray ''see-through'' imaging methods, high-speed fullfield surface measurements such as virtual field methods [22,23] and digital image correlation [24,25] provide valuable additional measurements on top of the traditional stress-strain curves.…”

Dynamic deformation and fracture of single crystal silicon: Fracture modes, damage laws, and anisotropy

“…Simultaneous dynamic x-ray imaging and diffraction have been established at the beamline 32-ID of the Advanced Photon Source (APS) [32][33][34], with a split Hopkinson pressure/tension bar (SHPB/SHTB) implemented for dynamic loading. Dynamic deformation of various materials such as Mg alloys, metal composites, and granular materials have been investigated with the digital image correlation and Laue diffraction [32,33,[35][36][37]. The simultaneous x-ray imaging and diffraction technique is rarely exploited for studying mechanical properties of single crystals during dynamic loading.…”