NTS News Center

Latest News in Testing, Inspection and Certification

NTS News Center - Latest News in Testing, Inspection and Certification

Advanced Testing Technology Meets Art Conservation: NTS lab assists in the digital exploration of medieval boxwood sculptures.

Thanks to the help and participation of our NTS Chesapeake Non-destructive Imaging Laboratory (formerly Chesapeake Testing), researchers have made advances in the study of medieval boxwood sculptures. The pieces are currently being featured in the exhibition Small Wonders: Gothic Boxwood Miniatures at the Met Cloisters, the branch of the Metropolitan Museum of Art dedicated to medieval art and architecture.

These intricately carved objects, some over 500 years old, are simply miraculous in the level of detail created in such small objects. The 3D digital data captured via micro CT scanning helped researchers shed light on the techniques and craftsmanship required to construct these pieces of art with such fine detail.

Micro CT scanning, much like medical CAT scan imaging, uses the material penetrating properties of x-rays to provide information from within an object, whiteout any destructive effects. Unlike medical CAT scanning, micro CT has the ability to obtain extremely high resolution images, thanks to the use of highly focused x-ray sources and higher resolution imaging panels.

This data gives historians and researchers a unique ability to virtually cross section the artifacts, without any risk of damage. In addition to being able to analyze the internal structure, the scanning process also captures full 3D surface information which can be used later on to 3D print replicas and allow for enriched public interaction with these delicate pieces of medieval history.

To learn more about these fantastic carvings, visit The Met website here: http://www.metmuseum.org/press/exhibitions/2016/small-wonders. The exhibition runs from February 22 through May 21, 2017.

190.473 ROSARY BEAD: SURFACE MODEL CREATED FROM 3D CT SCAN SHOWS HIGH LEVEL OF DETAIL DEPICTED IN CARVED SCENES. SURFACE DATA FROM THESE SCANS

17.190.473 ROSARY BEAD: CT DATA ALLOWS RESEARCHERS TO VIRTUALLY CROSS SECTION THE ARTIFACTS, PROVIDING A NEVER BEFORE SEEN VIEW INSIDE

X-Ray Computed Tomography Scanning & Composite Materials

X-ray inspection technology has come a long way over the past several decades. Since its inception in the 1970s, x-ray computed tomography, or CT scanning, has completely revolutionized medical diagnostic practices. In the 1980s, we saw the introduction of micro-focus x-ray technology, which had large implications for non-destructive testing in the industrial and scientific communities. It wasn’t however, until the new millennium that improvements in x-ray detection technology and computing power enabled commercially-viable micro-focus x-ray CT scanning.

With micro-focus CT scanning, data can be captured at incredibly high resolution, sometimes even at the sub-micron level. This makes CT scanning an extremely valuable tool in materials research, especially when analyzing composite materials and their internal structures. The raw scan data, which is usually several gigabytes (20 GB+), can be rendered in 3D and even numerically analyzed. The image below shows a 3D rendering of a small section of a carbon-epoxy structure captured at approximately a 4 micron resolution.

In this particular sample, a small composite block, the x-ray and imaging settings were optimized to enhance the contrast between the carbon fibers and epoxy resin. This enabled us to virtually segment and remove the resin material in order to expose the fiber structure. This data can be extremely valuable in evaluating structural properties of materials and different manufacturing processes. There are even software tools commercially available today that can numerically evaluate fiber consistency and orientation over an entire structure.

X-ray CT scanning is a very versatile process that can be performed on many different materials and even at different stages of a manufacturing process. The images above, show a high-resolution CT scan of a prepreg composite that has not yet been fully cured. In the image on the left (a single cross section), the brighter areas are the uncured resin material, and small openings and voids can be seen inside. These can also be numerically analyzed to provide far more data, including fiber volume fraction, both locally, and over a larger area.

Even on the more “macro” scale, micro-CT can be a very powerful tool in structural and failure analysis. Small defects such as porosity and thin delaminations can be visualized with high resolution images. Failure modes can be spotted and easily identified in even the most complex of structures. The image above shows a cross section image from a high-load bearing structure that failed during mechanical load testing. The origins and full extent of the failure can be studied without the use of any destructive techniques that may compromise the sample and data.

There are many applications of x-ray CT scanning in composite materials, and the list is rapidly growing. This type of testing has proven to be very beneficial in identifying damage and failure modes that previously had gone undetected, and has also provided the benefit of avoiding, often time-consuming, destructive analysis.

NTS Chesapeake operates one of the most powerful, high-resolution CT systems in use today. A large walk-in 450kV micro-focus system enables large objects (up to 37 inches in diameter) to be imaged with extremely high resolution. This system, combined with NTS’s other x-ray capabilities and state-of-the-art processing and visualization tools, allows this technology to solve numerous problems spanning many different industries.

 

3D Modeling Aids the “Digitization of Science”

CT ScannerIn January 2016, Popular Mechanics paid a visit to the Smithsonian’s Museum Support Center in Suitland, Maryland and met with Nick Pyenson, paleontologist and curator  of the Marine Mammal Collection, the largest and most comprehensive of its kind in the world.  The team at NTS Chesapeake has been providing CT X-ray scanning support to Pyenson in its large scale scanner, enabling him to study larger specimens from the collection, such as blue whale skulls.

Check out the Popular Mechanics article by Matt Blitz here.

X-Ray Computed Tomography (CT) Scanning & Battery Cells

Next-generation energy storage technologies, such as lithium-ion batteries, are changing the landscape of just about every major industry – from advanced aerospace applications to everyday consumer products. With the major advantage storing very high energy densities while remaining small in both size and weight, lithium-ion batteries are becoming more and more prevalent in electronic devices.  These batteries function differently than their predecessors and can be susceptible to different kinds of failure modes, including the very well-publicized “thermal runaway”, which has plagued even the largest aerospace programs and some of the most well-known consumer brands.

Understanding the results of battery testing and failure analysis is key to improving design and ensuring the proper functioning of internal safety features. X-ray CT scanning has proven to be an excellent method to obtain internal, three-dimensional data in a non-destructive manner. Industrial CT scanning has been used in the analysis of batteries for several years now, including some very high-profile investigations by the National Transportation Safety Board (NSTB). The images and data captured using NTS Chesapeake’s state-of-the-art CT scanning equipment were included in several NTSB reports.

Image of a damaged battery unit (left) and CT scan cross section of one of the cells (right), both taken from the NTSB Interim Factual Report on the 787 Dreamliner Investigation in 2013. (http://www.ntsb.gov/investigations/AccidentReports/Reports/DCA13IA037-interim-factual-report.pdf)

Image of a damaged battery unit (left) and CT scan cross section of one of the cells (right), both taken from the NTSB Interim Factual Report on the 787 Dreamliner Investigation in 2013.
(http://www.ntsb.gov/investigations/AccidentReports/Reports/DCA13IA037-interim-factual-report.pdf)

The industrial CT scanning process is very similar to a medical CAT scan, which uses high-resolution radio-graphic data captured at multiple angles around a part. Because the objects under test are inanimate and the operators are well-protected from any radiation, industrial techniques typically include higher x-ray energies and longer acquisition times in order to maximize resolution and quality on more dense, metallic components. This process has been accessible to research scientists for decades now, but only recently has it become more cost-effective, thanks in large part to advances in digital x-ray imaging and computer processing. This means that scanning and processing techniques that previously took hours or days, are now completed within minutes.

Two-dimensional digital x-ray radiograph (left) and 3D cross sections (right) from a CT scan of a common lithium ion battery design found in many cellphones and other mobile devices

Two-dimensional digital x-ray radiograph (left) and 3D cross sections (right) from a CT scan of a common lithium ion battery design found in many cellphones and other mobile devices

Much of the recent work including CT scanning of batteries often comes from the need to better understand and control the quality of consumer-grade battery cells. Issues span many types of everyday electronic devices from laptops and mobile phones, to popular motorized scooters and even e-cigarettes. Being able to obtain these internal images non-destructively creates many opportunities for improved quality control and failure analysis techniques. Data can be collected at different stages of charging or after certain types of destructive testing, such as extreme temperature, shock and vibration, and even ballistic and cell puncture testing. When it comes to analysis and high-level investigations involving suspected battery failures, one additional advantage of utilizing CT scanning is evidence preservation.

2d-cross-section-of-battery-cell

Two-dimensional image cross sections taken from a CT scan of a small cylindrical battery cell showing the internal structure of the layers (often called the “jelly roll”) and even the gel polymer electrolyte.

 

In addition to performing inspection and analysis for its clients, Chesapeake Testing has been exploring techniques for optimizing x-ray and CT scanning to better analyze battery cell structure and damage. This includes investigating methods to increase resolution and lower the noise caused by x-ray scatter, which can be detrimental to detailed image analysis, especially within larger cell designs. Academic research also continues into better imaging processes to detect and analyze failures, including in-situ, or real-time, imaging. Just last year, researchers at European Synchrotron Radiation Facility, led by University College London, performed high-speed radio-graphic and CT imaging of battery cells while under thermal runaway. Their results include some extraordinary images and videos taken from the data and can be found here: http://www.nature.com/articles/ncomms7924.

As echoed in the media and among industry experts, there is a pressing need to improve the quality and safety of these devices. Technologies such as x-ray computed tomography are providing engineers and researchers with the information needed to more effectively analyze failures and ultimately improve battery cell design. Even with all of the negative attention surrounding lithium-ion batteries, if manufactured correctly, there are still so many benefits. There can be little doubt that these battery technologies will continue to drive new advances in energy storage and be implemented in every facet of modern life.

NTS’ Chesapeake, MD division operates one of the most powerful, high-resolution x-ray CT scanning systems in use today. A large walk-in 450kV micro-focus system enables large objects (up to 37 inches in diameter) to be imaged with extremely high resolution. This system, combined with  NTS’s other testing capabilities and state-of-the-art processing and visualization tools, allows this technology to solve numerous problems spanning many different industries.

For additional information, visit the CT Scanning section of our website here: https://www.nts.com/services/non-destructive-testing/ct-scanning

New Species of Extinct River Dolphin Discovered in Smithsonian Collection

A fossil that has spent decades in the Smithsonian’s National Museum of Natural History has been determined to be a new genus and species after careful study that includes x-ray scanning and support for digital image processing from our Chesapeake Testing division!

The Arktocara yakataga skull was discovered in 1951 in southeastern Alaska. To learn more about this new discovery, check out the Smithosian article here. Click on the image below to experience the Smithsonian X3D model and explore the fossil.smithsonian-dolphin-3d