scholarly journals In situ observation of fracture processes in high-strength concretes and limestone using high-speed X-ray phase-contrast imaging

Author(s):  
Niranjan D. Parab ◽  
Zherui Guo ◽  
Matthew Hudspeth ◽  
Benjamin Claus ◽  
Boon Him Lim ◽  
...  

The mechanical properties and fracture mechanisms of geomaterials and construction materials such as concrete are reported to be dependent on the loading rates. However, the in situ cracking inside such specimens cannot be visualized using traditional optical imaging methods since the materials are opaque. In this study, the in situ sub-surface failure/damage mechanisms in Cor-Tuf (a reactive powder concrete), a high-strength concrete (HSC) and Indiana limestone under dynamic loading were investigated using high-speed synchrotron X-ray phase-contrast imaging. Dynamic compressive loading was applied using a modified Kolsky bar and fracture images were recorded using a synchronized high-speed synchrotron X-ray imaging set-up. Three-dimensional synchrotron X-ray tomography was also performed to record the microstructure of the specimens before dynamic loading. In the Cor-Tuf and HSC specimens, two different modes of cracking were observed: straight cracking or angular cracking with respect to the direction of loading. In limestone, cracks followed the grain boundaries and voids, ultimately fracturing the specimen. Cracks in HSC were more tortuous than the cracks in Cor-Tuf specimens. The effects of the microstructure on the observed cracking behaviour are discussed. This article is part of the themed issue ‘Experimental testing and modelling of brittle materials at high strain rates’.

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Brandon A. Sforzo ◽  
Alan L. Kastengren ◽  
Katarzyna E. Matusik ◽  
Felipe Gomez del Campo ◽  
Christopher F. Powell

Abstract Modern aircraft engines combine liquid fuel and air using an intricate flow device with many fuel and air flow passages. To date, the process by which the fuel atomizes within this swirler set has not been examined directly due to optical access limitations. In this work, high-speed X-ray phase-contrast imaging of a liquid spray inside a gas turbine engine swirler geometry is presented. Measurements were carried out at the 7-BM beamline of the Advanced Photon Source at Argonne National Laboratory using the high-energy broadband X-ray beam. The synchrotron X-ray source provides the necessary photon energy and flux to capture time-resolved fluid phenomena within the confines of the relevant geometry while liquid and air are flowing. Spray nozzle hardware and geometries were provided by the National Jet Fuels Combustion Program (NJFCP), allowing for characterization of the spray using a commercially relevant configuration. Modified swirlers were three-dimensional printed with acrylic to improve imaging access while maintaining influential internal features. Water was used as a surrogate fluid for these studies to demonstrate the visualization capabilities. The experiments were conducted at atmospheric exit pressure conditions with a pressure drop of 6% across the swirler. High-speed imaging of the pilot spray cone revealed sheet breakup several millimeters downstream of the orifice exit, upon interaction with the radial assist air flow. These droplets and ligaments were observed to impinge on the inner filming surface of the swirler and flow toward the exit while developing a tangential flow. Under these conditions, the liquid film grows up to several hundred microns in thickness on the filming surface, and subsequently forms ligaments up to several millimeters in length before breaking up. This work demonstrates the capability of X-ray diagnostics in visualizing liquid flows within solid geometries of technical relevance. Furthermore, the spatial quantification of filming flows and liquid interaction with the swirler air provides validation data for modeling of the multiphase flows and surface interactions within the swirler.


IUCrJ ◽  
2020 ◽  
Vol 7 (6) ◽  
pp. 1131-1141
Author(s):  
Isabelle Martiel ◽  
Chia-Ying Huang ◽  
Pablo Villanueva-Perez ◽  
Ezequiel Panepucci ◽  
Shibom Basu ◽  
...  

Serial protein crystallography has emerged as a powerful method of data collection on small crystals from challenging targets, such as membrane proteins. Multiple microcrystals need to be located on large and often flat mounts while exposing them to an X-ray dose that is as low as possible. A crystal-prelocation method is demonstrated here using low-dose 2D full-field propagation-based X-ray phase-contrast imaging at the X-ray imaging beamline TOMCAT at the Swiss Light Source (SLS). This imaging step provides microcrystal coordinates for automated serial data collection at a microfocus macromolecular crystallography beamline on samples with an essentially flat geometry. This prelocation method was applied to microcrystals of a soluble protein and a membrane protein, grown in a commonly used double-sandwich in situ crystallization plate. The inner sandwiches of thin plastic film enclosing the microcrystals in lipid cubic phase were flash cooled and imaged at TOMCAT. Based on the obtained crystal coordinates, both still and rotation wedge serial data were collected automatically at the SLS PXI beamline, yielding in both cases a high indexing rate. This workflow can be easily implemented at many synchrotron facilities using existing equipment, or potentially integrated as an online technique in the next-generation macromolecular crystallography beamline, and thus benefit a number of dose-sensitive challenging protein targets.


2013 ◽  
Vol 84 (2) ◽  
pp. 025102 ◽  
Author(s):  
M. Hudspeth ◽  
B. Claus ◽  
S. Dubelman ◽  
J. Black ◽  
A. Mondal ◽  
...  

2016 ◽  
Vol 109 (13) ◽  
pp. 131903 ◽  
Author(s):  
Niranjan D. Parab ◽  
Zane A. Roberts ◽  
Michael H. Harr ◽  
Jesus O. Mares ◽  
Alex D. Casey ◽  
...  

2021 ◽  
Vol 207 ◽  
pp. 108565
Author(s):  
Jinling Gao ◽  
Nesredin Kedir ◽  
Cody D. Kirk ◽  
Julio Hernandez ◽  
Junyu Wang ◽  
...  

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Tanja Schulz-Mirbach ◽  
Margie Olbinado ◽  
Alexander Rack ◽  
Alberto Mittone ◽  
Alberto Bravin ◽  
...  

2005 ◽  
Vol 297-300 ◽  
pp. 1189-1195 ◽  
Author(s):  
Hiroyuki Toda ◽  
Tomomi Ohgaki ◽  
Kentaro Uesugi ◽  
Koichi Makii ◽  
Yasuhiro Aruga ◽  
...  

Synchrotron X-ray microtomography has been utilized for the 3D characterisation of microstructure in the cell materials of aluminium foams. Tomographs, consisting of about 109 isotropic voxels with a maximum of 1.0µm edge, were collected at the SPring-8 in Japan. A combination of high-resolution phase contrast imaging technique and several state-of–the-art application techniques has enabled the quantitative image analyses of micro-pore, intermetallic particles and grain boundary as well as the assessment of their effects on compressive deformation and fracture behaviours in two kinds of aluminium foams.


Sign in / Sign up

Export Citation Format

Share Document