In situ damage assessment using synchrotron X-rays in materials loaded by a Hopkinson bar

Abstract

Split Hopkinson or Kolsky bars are common high-rate characterization tools for dynamic mechanical behaviour of materials. Stress–strain responses averaged over specimen volume are obtained as a function of strain rate. Specimen deformation histories can be monitored by high-speed imaging on the surface. It has not been possible to track the damage initiation and evolution during the dynamic deformation inside specimens except for a few transparent materials. In this study, we integrated Hopkinson compression/tension bars with high-speed X-ray imaging capabilities. The damage history in a dynamically deforming specimen was monitored in situ using synchrotron radiation via X-ray phase contrast imaging. The effectiveness of the novel union between these two powerful techniques, which opens a new angle for data acquisition in dynamic experiments, is demonstrated by a series of dynamic experiments on a variety of material systems, including particle interaction in granular materials, glass impact cracking, single crystal silicon tensile failure and ligament–bone junction damage.

Real-time visualization of dynamic particle contact failures

“…The particles were compressed dynamically using a modified Kolsky bar setup and failure mechanisms were captured using a high speed synchrotron X-ray Phase Contrast Imaging (PCI) at Advanced Photon Source (APS) beam line 32-ID-B at Argonne National Laboratory, Argonne, IL. This experimental method has been used to study the failure mechanisms in various materials including bone-tissue interfaces, polymer fibers, concrete and rocks, and glass plates (11)(12)(13). The schematic of the experimental setup is presented in Fig.…”

High speed X-ray phase contrast imaging of energetic composites under dynamic compression

“…This setup has been used to study the dynamic fracture mechanisms in various materials, including brittle particles, 26,27 glass plates, 28 high performance fibers, 29 and bone-tissue interfaces. 30 The complete details of the experimental setup FIG. 1.…”

“…2016) are described previously. 30,31 The schematic of the experimental setup is presented in Figure 1.…”

X-ray imaging of subsurface dynamics in high-Z materials at the Diamond Light Source

“…In recent examples, loading has been generated using either a small-bore gas-gun or Hopkinson pressure bar. [9][10][11]17 Such systems are commonly driven with high-pressure gas, in which "firing" is performed through the rapid delivery of this pressure to the back of a projectile or striker bar. This is often accomplished using a high-speed valve, however variations in projectile or o-ring dimensions, barrel cleanliness, system vacuum, and the simple response of the valve itself, result in impact jitter (variation in impact time) on the order of milliseconds.…”