Browse Topic: Computed tomography (CT)

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A Combined X-Ray CT and Mechanistic Characterization of Bearing Failure Mechanisms in Bolted Composite ComponentsF-0077-2021-168975/10/2021
ABSTRACT
Fulghum, Ethan, Kariyawasam,  Supun, Saathoff,  Caleb, Lua, Jim, Cui,  Xiaodong, Xiao,  Jian
Nondestructive Inspection Program Requirements for Aerospace SystemsAS6870 (Historical)12/10/2020
This SAE Aerospace Standard defines the requirements for establishing a Nondestructive Inspection (NDI) program for aerospace systems to include but not not be limited to aircraft structure, aircraft stores (external structures such as antennas, pods, fuel tanks, weapons, radomes, etc.) and missile/rocket structural components when an NDI Program Plan is required by contract. NDI Programs are essential to ensuring NDI processes are implemented to support the lifecycle design requirements of the system and its components. NDI Programs are applicable to all phases of the system life cycle, including acquisition, modification, and sustainment. This standard may also be applicable to mechanical equipment, subsystems, and propulsion systems, but the requirements defined by the NDI Program Plan should be tailored by the contracting agency for such use. An NDI Program Plan shall be developed at the beginning of the technology development phase and shall define all NDI requirements to be adhered to throughout the system life cycle.
AMS K Non Destructive Methods and Processes Committee
Digital Twin Approach for Structural Property Evaluation of Next Generation Active Twist BladesF-0076-2020-1636610/5/2020
The digital twin (DT) refers to a digital replica or virtual model of actual physical product or process that can be applicable for various purposes. In this study, a digital reproduction of the next generation active twist blade, meeting superior durability characteristics and high strength requirements under severe operating environments of a helicopter rotor, is attempted using the up-to-date computed tomography (CT) scheme combined with modern digital image processing technique. The CT scan covers much portion of the blade root, transition, and tip regions where substantial variations in external geometries and/or interior structural layouts are present while limited zones in the airfoil blade region being considered as nonuniform. A three-dimensional (3D) finite element-based DT simulation model is constructed using the high-resolution CT-scan images. The detailed lamination geometries and sequences of layered composites in the blade skin and spar are implemented in the DT model which can be exploited further for durability study or strength analysis. The reconstructed 3D analysis model is used to determine the structural properties of the blade. In parallel, either mechanical or optical measurement methods along with two-dimensional (2D) blade sectional analysis are carried out to cross validate their predictions. Overall, fair to good correlation is obtained between the different set of results. The agreement is good for mass, elastic axis, and flap bending while less satisfactory results are obtained with the torsion rigidity. A sensitivity analysis is also conducted to clarify the impact of modeling cables, nose weight, and manufacturing imperfections on the structural property evaluation of the blade.
Hwang, Hyun, Kalow, Steffen, Ahn, Jun, Chang, Sehoon, Jung, Sung, Keimer, Ralf
Powering Up Medtech’s Modalities: Top Trends and Design ConsiderationsTBMG-373508/1/2020
We are living in a digitally integrated and connected world. Evidenced by the use of smartphones, smartwatches, and other smart devices, there is no ending this trend. This holds true across many industries and applications, but is especially prevalent within medtech devices — a market that’s predicted to reach $432.6 billion by 2025.1
Mechanical Response of Laterally-Constrained Prismatic Battery Cells under Local Loading2020-01-02004/14/2020
The crash safety of lithium-ion batteries has received great attention in recent years because of their growing popularity in electric vehicles. However, the safety issues of prismatic batteries have not been thoroughly studied; in particular, the mechanical responses of prismatic battery cells with lateral constraints under varied loading conditions still remain unclear. In this study, indentation tests are conducted to study the mechanical response of prismatic battery cells. Fixtures providing lateral constraint which simulates the real packing situation in battery module are designed. Firstly, the effects of lateral constraints on coupled mechanical and electrical responses of prismatic battery cells are analyzed and discussed. Secondly, dynamic indentation tests of prismatic cells with lateral constraints are carried out. The response of the stacked batteries under local loading is revealed. Thirdly, non-destructive X-ray computed tomography imaging technique is employed to detect the fracture patterns in battery cells caused by indentation. The results of indentation tests indicate that the indentation depth and the peak force for the battery internal failure are affected by the side constraint conditions and the responses of battery cells vary under different loading speeds. Also, the XCT scanning results of the samples clearly show the different levels of internal damage and fracture patterns under varied conditions. The detailed mechanical responses of the prismatic battery cell disclosed in the present study can provide support for modeling and protection of batteries under side impact.
Xiao, Feiyu, Xing, Bobin, Xia, Yong
Advanced analytical methods for the study of lubricant-derived ash and associated impacts on engine aftertreatment components2019-01-229312/19/2019
Catalytic and non-catalytic engine aftertreatment components, such as the diesel oxidation catalyst (DOC), selective catalytic reduction on filter (SCRF), the gasoline particulate filter (GPF) and the diesel particulate filter (DPF) are complex, multifunctional emissions control technologies that are robustly designed for extended use in harsh automotive exhaust environments. Over the useful component lifetime, lubricant-derived inorganic and incombustible ash accumulates in and/or on the surface of the aforementioned aftertreatment components, resulting in degraded performance and other potential problems. In order to better understand effects of ash in such components, a multiscale analytical approach is necessary, requiring a variety of experimental tools. This paper will briefly present a decade of analytical experience at the Sloan Automotive Laboratory at the Massachusetts Institute of Technology and at Kymanetics, Inc., specific to the fundamental understanding of the accumulation of lubricant-derived ash in engine aftertreatment components. Several key experimental tools and techniques will be reviewed including focused ion beam milling (SEM), in-situ X- ray diffraction (XRD), atomic force microscopy (AFM), ultra-high resolution X-ray computed tomography (CT), X-ray fluorescence (XRF), environmental scanning electron microscopy with backscattered electrons (ESEM-BSE), and ultra-small angle X-ray scattering (USAXS), among others.
Kamp, Carl Justin, Bagi, Sujay Dilip
Human Torso SimulatorTBMG-3570512/1/2019
Engineers have created a simulator that mimics the mechanical behavior of the human torso. It allows researchers to test different back brace designs and configurations without needing to test them on people, removing significant logistical and ethical issues.
X-ray Measurement Approach Could Improve CT ScannersTBMG-3544211/1/2019
A new measurement approach could lead to a better way to calibrate computed tomography (CT) scanners, potentially streamlining patient treatment by improving communication among doctors.
Microrobots Activated by Laser Pulses for Treating TumorsTBMG-351539/1/2019
Microrobots that can deliver drugs to specific spots inside the body while being monitored and controlled from outside the body have been developed that also can treat tumors in the digestive tract.
Industrial CT is Hip: Quality of Life Enhanced with Additive ManufacturingTBMG-349788/1/2019
Orthopedic devices play a crucial role in providing pain relief, improving mobility, and enhancing the quality of life for patients suffering from musculoskeletal disorders. The medical devices and procedures used in orthopedics are constantly being upgraded due to changing consumer needs. Technological advancements and integration of digital technologies have triggered changes in demand, for patients and healthcare professionals alike.
AI Enables Low-Dose CT ScansTBMG-349698/1/2019
Researchers have developed an artificial intelligence (AI) technique that uses image post-processing to rapidly convert low-dose computed tomography (CT) scans to images of superior quality, compared to low-dose scans that do not use the AI technique.
Surgeons Use Augmented Reality to Reconnect Blood VesselsTBMG-349258/1/2019
Following severe trauma, patients may have tissue damage or open wounds that require reconstructive surgery using fasciocutaneous flaps. These flaps of tissue, which are taken from elsewhere on the body and include the skin and blood vessels, are used to cover the wound and enable it to close and heal properly. A vital step in the process is connecting the blood vessels of the new tissue with those at the site of the wound, so oxygenated blood can reach the new tissue and keep it alive.
Image-Analysis Software Sees Cancer in 3DTBMG-349288/1/2019
Spinoff is NASA's annual publication featuring successfully commercialized NASA technology. This commercialization has contributed to the development of products and services in the fields of health and medicine, consumer goods, transportation, public safety, computer technology, and environmental resources.
AI Spots Lung Cancer Before RadiologistsTBMG-348137/1/2019
Deep learning — a form of artificial intelligence — was able to detect malignant lung nodules on low-dose chest computed tomography (LDCT) scans with a performance meeting or exceeding that of expert radiologists.
Full-Spectrum Infrasonic Stethoscope for Screening Heart, Carotid Artery, and Lung-Related DiseasesTBMG-346196/1/2019
Microphones and stethoscopes are regularly used by physicians to detect sounds when monitoring physiological conditions. These monitors are coupled directly to a person's body and measure in certain bandwidths either by listening or by recording the signals. The physiological processes, such as respiration and cardiac activity, are reflected in a different frequency bandwidth from 0.01 Hz to 500 Hz.
Monitor Babies in the NICU Without WiresTBMG-345816/1/2019
An interdisciplinary Northwestern University team has developed a pair of soft, flexible wireless sensors that replace the tangle of wire-based sensors that currently monitor babies in hospitals’ neonatal intensive care units (NICU) and pose a barrier to parent-baby cuddling and physical bonding. The lead researcher was John A. Rogers, a bioelectronics pioneer, who led the technology development. The team recently completed a series of first human studies on premature babies at Prentice Women’s Hospital and Ann & Robert H. Lurie Children’s Hospital of Chicago. The researchers concluded that the wireless sensors provided data as precise and accurate as that from traditional monitoring systems. The wireless patches also are gentler on a newborn’s fragile skin and allow for more skin-to-skin contact with the parent. Existing sensors must be attached with adhesives that can scar and blister premature newborns’ skin. The study, involved materials scientists, engineers, dermatologists, and pediatricians. It includes initial data from more than 20 babies who wore the wireless sensors alongside traditional monitoring systems, so the researchers could do a side-by-side, quantitative comparison. Since then, the team has conducted successful tests with more than 70 babies in the NICU.
In-process Defect Monitoring and Correction in Additive Manufacturing of Aluminum AlloysF-0075-2019-146235/13/2019
Metal additive manufacturing (AM) has become increasingly popular to fabricate complex, light-weight, and high- efficiency components for use in the aerospace industry; however, there are inherent limitations in existing AM processes that have delayed widespread implementation for aviation applications. Porosity is just one example of the key characteristics that can impact the mechanical strength of an AM part. This research focuses on a real-time feedback system to detect and correct defects during the powder bed fusion process of aluminum alloys. In this study, AlSi10Mg coupons were built using various AM parameters. The build process was continuously monitored via a high-frequency in-situ infrared camera which had been integrated into a commercial metal powder bed fusion machine. Porosity information (pore location and size) of the as-built AM coupons were characterized using x-ray computed tomography. The monitoring results were post processed and correlated with porosity location, indicating a strong relationship between abnormal sensing signal and pore formation. This demonstrates that the real-time abnormal sensing signal can be a good indicator for identifying pore formation during the AM process. Additionally, Sentient Science Corporation (Sentient) used its advanced modeling technique to simulate the AM build process regarding the melt pool geometry, porosity, and microstructure. Prediction of porosity level at different AM parameters aligned well with the experimental results. Advanced modeling results showed that careful selection of AM settings is required to correct in-process defects. Repair parameters must be tailored to achieve satisfactory correction of individual defects. Combining the in-situ defect monitoring and advanced simulation capabilities enables the creation of a closed-loop feedback control system that provides automatic defect detection and correction action in powder bed additive manufacturing process.
Jalalahmadi, Behrooz, Slotwinski, John, Liu, Jingfu, Rios, Jason, Peitsch, Christopher, Goldberg, Arnold, Montalbano, Timothy
Dining on Data19AVEP05_065/1/2019
Processing, in real-time, the enormous data stream that's flowing through AVs is increasingly the job of NVIDIA's mighty GPUs. Danny Shapiro relishes the feast. Every year, NVIDIA hosts its GPU Technology Conference (GTC), a multi-day news conference/expo to highlight the advances the tech company has made in the past 12 months. In 2018, the big automotive news at GTC was the introduction of DRIVE Constellation, a simulation system designed to “train” the artificial intelligence (AI) algorithms used for autonomous driving. One year and countless line of code updates later, NVIDIA announced at GTC 2019 that the Toyota Research Institute-Advanced Development (TRI-AD) would be the first publicly named customer for DRIVE Constellation. Danny Shapiro, NVIDIA's senior director of automotive, could have used the moment as an excuse to celebrate. Instead, he was all business as he sat down with SAE's Autonomous Vehicle Engineering and contemplated the work still to do.
Blanco, Sebastian
3D Printer Uses Rays of Light to Shape ObjectsTBMG-343885/1/2019
Most 3D printers, including light-based techniques, build up 3D objects layer by layer. This leads to a “stair-step” effect along the edges. They also have difficulties creating flexible objects because bendable materials could deform during the printing process, and supports are required to print objects of certain shapes, like arches.
Fast and Accurate Simulation of Manufactured Parts with DefectsTBMG-343985/1/2019
Unwanted porosity is typical to many manufacturing processes — from traditional casting to additive manufacturing (3D printing) — and is difficult to avoid entirely. Manufacturers need to know what amount of porosity is tolerable inside a part without affecting its strength and performance.
Reliable Structures and Wearable Systems Call for Multiphysics SimulationTBMG-344425/1/2019
The increasing demand for miniaturized electronics and Internet of Things (IoT) devices has created new challenges for the specialists who design microdevices such as actuators, controllers, drivers, sensors, and transmitters. From responsive equipment and wearable monitors to energy efficient lighting in the office and automation in the factory, engineers need to bridge the microscopic components of semiconductors and our macroscopic world with reliable and innovative products. This shift has inspired engineers to find new solutions by exploring their ideas in the virtual world of numerical simulation.
Non-Destructive Evaluation for High-Pressure Composite Tubes using a Hybrid Approach2019-01-12684/2/2019
Recently, composite materials/structures are getting increasingly used in the automotive and aerospace industry. Defects issue is commonly associated with the use of composite materials/structures. Reliable Non-Destructive Evaluation (NDE) of composite structures is still challenging due to the existence of small size defects. In this research, a hybrid approach is used to accurately determine small size internal defects. In this hybrid approach, X-Ray Computed Tomography is used as a reference to accurately determine all defect locations, then a digital shearography method is used to conduct fast NDE for in-line testing. The critical shearographic NDE parameters such as shearing angle, shearing distance and loading amount are determined and optimized based on the X-ray CT scan result. From the comparison of X-ray CT scan results and digital shearography NDE results, the detection rate of digital shearography for defects with a size of larger than 1mm is from 91.91% to 97.30%. The detection rate of digital shearography For defects with a size of 0.4mm - 1mm is from 54.17% to 84.48%. The Shearographic NDE fundamentals, experimental setup, and testing results are shown in detail in this paper.
Xie, Xin, Zhou, Zhou, Kolambe, Himanshu, Bothe, Abhijit
Quantitative Analysis of Ash Density and Ash Distribution inside DPF Honeycomb Channels Based on X-ray Computed Tomography2019-01-09794/2/2019
Simulation of soot and ash deposits in diesel particulate filters (DPF) often assumes uniform distributed cake-layer and/or plug accumulation at the very end section of the inlet channels, which may not reflect some conditions in the field. For example, cake-layer thickness changes along the filter length, and plugs show up not only at the end section but also at the middle section or even near the inlet section. This paper presents detailed microscopic analytical techniques which have been developed and applied to quantitatively derive the density and distribution of ash deposits inside DPF honeycomb monoliths. The ash loading experiments were done in a combined engine/burner test facility. Specifically, X-Ray tomography (X-Ray CT) was used extensively, which has the advantage of non-contaminating the ash deposits. A unique 2D and 3D data processing procedure was developed so that quantitative and statistical analyses could be done to extract ash layer/end-plug deposition information. With the technique, the quantitative ash distribution information will be useful as inputs to theoretical model for better and more accurate analysis and prediction. The key feature of the technique lies in analyzing the samples in multiple perspectives, to be described in the paper, in deriving the 3D information. Catalyst coated cordierite DPF was used to collect lab generated soot and ash from a single cylinder diesel engine and oil-burner. DPF loading process continues until the pressure drop reaches 10 kPa at a space velocity of 40000/h, and regeneration process follows with duration of 1 hour. After cycles of loading and regeneration, the DPF filter was removed from the bench and scanned by the X-Ray CT system. On one hand, thousands of 2D images were sliced out from the DPF and analyzed with self-developed program with MATLAB, which can provide the ash packing density and distribution information of both cake-layer and end-plug ash accumulation. On the other hand, 3D DPF ash volume was post-processed to extract all of the ash plugs (end-channel or mid-channel) and their spatial distribution, radially and axially along the channels. With the 2D image processing and comparison with standard powder samples, collected ash can be classified into a few different groups and measured separately; hence, distribution of ash with different densities and fractions of each density group can be characterized. For scanned 3D volumetric data, spatial distribution, plug length and volume can be summarized with the 3D measurements and analysis. Finally, information about the number of plugged channels and the plug ratio of each channel can be obtained as well. With the specific image processing and statistical analysis, described in the paper, more details of the ash deposits can be examined. These results can be used as input for modeling work, generate accurate predictions for calibrations in DPF feedback control, and more importantly for solving the main problems that could potentially lead to DPF failure.
Wang, Yuesen, Wong, Victor
Design of High Performance Coated GPF with 2D/3D Structure Analysis2019-01-09774/2/2019
In recent years along with stringent the regulations, vehicles equipped with gasoline particulate filter (GPF) have started to launch. Compared to bare GPF, coated GPF (cGPF) requires not only PN filtration efficiency, low pressure drop, but also purification performance. In the wall flow type cGPF having a complicated the pore shape, the pore structure further irregularly changes depending on the coated state of the catalyst, so it is difficult to understand the matter of in-wall. In order to advance of cGPF function, it was researched that revealing the relevance between pore structure change in the wall and GPF function. Therefore, to understand the catalyst coated state difference, cGPF of several coating methods were prepared, and their properties were evaluated by various analyses, and performance was tested. First of all, as a result of Mercury porosimetry analysis revealed that the pore diameter of the filter wall of GPF is a key factor for the pressure drop and the Particulate Number filtration efficiency. Next, as a result of analyzing the 3D model created by the μX-ray computed tomography image, it was found that the uniformity of the catalyst coat is a key factor for the purification performance. On the other hand, from images showing catalyst coated state of cGPF using electron probe micro analyzer, it was possible to quantify and evaluated uniform of catalyst coated state, by 2D digital image analysis. From the above those studies, cGPF could become to be designed with the best balance of low pressure drop, high purification performance and high PN filtration efficiency.
Seki, Chiaki, Watanabe, Takayuki, Mori, Takeshi, Furukawa, Atsushi, Satoh, Naohiro, Imai, Yusuke, Matsuo, Yuichi
Phenomenological Investigations of Mid-Channel Ash Deposit Formation and Characteristics in Diesel Particulate Filters2019-01-09734/2/2019
Accumulation of lubricant and fuel derived ash in the diesel particulate filter (DPF) during vehicle operation results in a significant increase of pressure drop across the after-treatment system leading to loss of fuel economy and reduced soot storage capacity over time. Under certain operating conditions, the accumulated ash and/or soot cake layer can collapse resulting in ash deposits upstream from the typical ash plug section, henceforth termed mid-channel ash deposits. In addition, ash particles can bond (either physically or chemically) with neighboring particles resulting in formation of bridges across the channels that effectively block access to the remainder of the channel for the incoming exhaust gas stream. This phenomenon creates serious long-term durability issues for the DPF, which often must be replaced. Mid-channel deposits and ash bridges are extremely difficult to remove from the channels as they often sinter to the substrate. The current study is comprised of analyzing field-return/field-aged DPF units exhibiting variations in ash bridging, characterized by high resolution X-ray CT, XRD, XRF and SEM-EDS. X-ray CT with a transmission X-ray source (voxel size ~700nm) was utilized for direct and accurate 3D visualization of the individual ash particles (which have an average size of 1-2μm), catalyst substrate structure and the ash which penetrates into the substrate surface pores. Data from X-ray imaging and ash chemical makeup, combined with data from field operation provide a deeper insight into understanding mechanisms that are responsible for mid-channel deposits. Details about the sample preparations necessary for X-ray CT, the combination of CT data and other characterization techniques, the comparison between on-road/off-road operating conditions and long-term durability implications of the DPF due to mid-channel ash deposits and ash bridging will be discussed. In addition, an open source CFD tool is discussed in the context of simulating 3D flow within DPF inlet channels which contain mid-channel deposits.
Kamp, Carl Justin, Bagi, Sujay, Wang, Yujun
Consideration of Corrosion Behavior of Aluminum Wire at Crimped Terminal and Effective Anti-Corrosion Treatment2019-01-04864/2/2019
The demand for weight reduction of vehicles is growing in compliance with CO2 emission control requirements. Also, demand for copper is on the rise with an increase in the number of electric vehicles because their motors and wiring require a lot of copper. This has raised concerns about higher copper prices and vehicle weight. Recently, attempts to reduce vehicle weight have been actively made by partially replacing copper with aluminum, which is lighter and less expensive. Although the use of aluminum wires on limited areas of some vehicles has already been reported, that on all areas has not been reported yet. The authors focus on reducing weight of wiring harnesses, which is about 20 kg per vehicle, and consider using aluminum instead of copper as the conductor of the electrical wires. One of the factors impeding the use of aluminum wires in wider areas is galvanic corrosion occurring at crimped terminals. Since aluminum causes galvanic corrosion when the metal is in electrical contact with a different metal in an electrolyte, it is essential to prevent this phenomenon from occurring at crimped terminals in mounting aluminum wires on vehicles. An anti-corrosion treatment needs to effectively prevent the occurrence of corrosion at the locations where aluminum wires are used. To devise an appropriate anti-corrosion treatment, it is necessary to grasp how aluminum wires corrode at the crimped terminals. This paper describes findings from a study of corrosion behavior of aluminum wires at crimped terminals for the purpose of developing an effective anti-corrosion treatment to increase the area onto which aluminum wires can be used.
Kawaguchi, Takuya, Fukaura, Keiji, Nakamura, Yuki, Mochizuki, Makoto, Otani, Satoshi
Durability Study of a High Pressure Common Rail Fuel Injection System Using Lubricity Additive Dosed Gasoline-Like Fuel - Additional Cycle Runtime and Teardown Analysis2019-01-02634/2/2019
This study is a continuation of previous work assessing the robustness of a Cummins XPI common rail injection system operating with gasoline-like fuel. All the hardware from the original study was retained except for the high pressure pump head and check valves which were replaced due to cavitation damage. An additional 400 hour NATO cycle was run on the refurbished fuel system to achieve a total exposure time of 800 hours and detect any other significant failure modes. As in the initial investigation, fuel system parameters including pressures, temperatures and flow rates were logged on a test bench to monitor performance over time. Fuel and lubricant samples were taken every 50 hours to assess fuel consistency, metallic wear, and interaction between fuel and oil. High fidelity driving torque and flow measurements were made to compare overall system performance when operating with both diesel and light distillate fuel. Injector rate shapes were measured as a function of time, and high resolution x-ray imaging of the nozzle tips was performed as part of the final teardown analysis. At the end of testing, there was a loss of rail pressure control at low fueling rates due to cavitation of the pump inlet check valve, consistent with prior findings. Excessive fuel-in-oil dilution was not observed under normal operating conditions, and there was no indication of significant fuel contamination by oil as evidenced by elemental analysis. The gasoline-like fuel required higher fuel system driving power and had a lower hydraulic efficiency than diesel due to a combination of higher vapor formation and leakage flow. Injectors exhibited reduced fueling rates after 600 hours of exposure and showed significant signs of cavitation damage within the nozzle tip. However, fuel wetted components in sliding contact did not show extraordinary signs of wear, potentially due to the use of lubricity additive.
Tzanetakis, Tom, Traver, Michael, Costanzo, Vincent, Medina, Roberto, Nelson, John, Matusik, Katarzyna, Sforzo, Brandon, Kastengren, Alan, Powell, Christopher
Create the Future Design Contest Alumni Achieve Market SuccessTBMG-339343/1/2019
The Create the Future Design Contest, launched in 2002 by the publishers of Tech Briefs magazine, helps stimulate and reward engineering innovation. The annual event has attracted more than 15,000 product design ideas from engineers, entrepreneurs, and students worldwide.
Predicting Leaky Heart Valves with 3D PrintingTBMG-337252/1/2019
More than one in eight people aged 75 and older in the United States develop moderate-to-severe blockage of the aortic valve in their hearts, usually caused by calcified deposits that build up on the valve's leaflets and prevent them from fully opening and closing. Many of these older patients are not healthy enough to undergo open heart surgeries; instead, they have artificial valves implanted into their hearts using a procedure called transcatheter aortic valve replacement (TAVR), which deploys the valve via a catheter inserted into the aorta. There are challenges with this procedure, however, including the need to choose the perfect-sized heart valve without ever actually looking at the patient's heart: too small, and the valve can dislodge or leak around the edges; too large, and the valve can rip through the heart, carrying a risk of death. Like Goldilocks, cardiologists are looking for a TAVR valve size that is “just right.”
Titanium Alloy Preforms from Plasma Arc Directed Energy Deposition Additive Manufacturing on Substrate Ti-6Al-4V Stress RelievedAMS7004 (Current)1/31/2019
This specification covers preforms fabricated up through 5.5 inches (140 mm) inclusive in deposition width thickness (see 8.2.5) using a Plasma Arc Directed Energy Deposition (PA-DED) additive manufacturing process on a Ti-6Al-4V substrate that are subjected to post-deposition stress relief heat treatment. This is a wire fed additive manufacturing process. If required by the CEO, preforms may require subsequent machining to meet requirements for their intended final part application.
AMS AM Additive Manufacturing Metals
Human Images from World's First Total-Body Medical Scanner UnveiledTBMG-335651/1/2019
EXPLORER, the world's first medical imaging scanner that can capture a 3D picture of the whole human body at once, has produced its first scans.
Imaging System Makes Back Surgery Safer, Faster, Less ExpensiveTBMG-335481/1/2019
Researchers at Dartmouth have found a way to make back surgery safer, faster, and more cost effective. MRIs and CT scans can help surgeons identify spine problems such as compressed vertebrae or herniated disks. But finding a clear path to those problem areas is not always straightforward. Tissue and bone not only stand in the way, they can also move during spinal surgery, rendering a CT scan taken prior to surgery much less accurate. To solve this problem, Dartmouth professors from the Thayer School of Engineering and Geisel School of Medicine developed a 3-dimensional, real-time optical tracking system to guide back surgeons as they operate — like a Google Maps for the body.
Customizing Implants With 3D Image ProcessingTBMG-335621/1/2019
Long-term patient comfort is a key part in any implant surgeries. Accurate placements of implants, of knees, hips, and other medical devices, is crucial to reducing the risk of discomfort and the need for costly revision surgeries. Custom-designed implants and simulation is a field of growing importance, giving clinicians and designers freedom to tailor designs for patients and make more informed surgical decisions. In addition to streamlining the manufacturing process, this approach enables multiple implant variations and pathologies to be considered at the virtual stage through additive manufacturing. This is as opposed to finding and correcting problems through trial and error.
Computed Tomography Inspection Applications in Additive ManufacturingTBMG-335911/1/2019
The ability of additive manufacturing to manage small volumes, create complex designs, and fabricate lightweight but strong structures makes it a natural fit for aerospace applications, where it is crucial to decrease weight. Just a small savings in weight on an aircraft can mean big savings in fuel consumption, which is good for the industry as well as the environment. That's why strong but lightweight carbon or glass fiber-reinforced materials are increasingly used in the aerospace industry; however, inspecting these materials poses a major challenge because they are geometrically complex.
New X-Ray Scanning Method Reveals How Particles Move in SolutionTBMG-335531/1/2019
A new method of X-ray scanning will allow for the visualization of many more biological molecules, providing critical information about what is inside molecules to scientists who currently can only access their outer shape or envelope. Such information could be a major boost to studies of viruses, for example.
On-Chip Optical Filter Processes Wide Range of Light WavelengthsTBMG-3327511/1/2018
MIT researchers have designed an optical filter on a chip that can process optical signals from across an extremely wide spectrum of light at once, something never before available to integrated optics systems that process data using light. The technology may offer greater precision and flexibility for designing optical communication and sensor systems, studying photons and other particles through ultrafast techniques, and in other applications.
COSMIC Impact: Next-Gen X-Ray Microscopy PlatformTBMG-328789/1/2018
A next-generation X-ray beamline now operating at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) brings together a unique set of capabilities to measure the properties of materials at the nanoscale.
Optimized Imager Tracks Cancer and Stem Cells in Medical ResearchTBMG-324918/1/2018
After earning his doctorate, Debashish Roy set about creating a business from the biological imaging device he'd helped invent as a graduate student. The system held promise for cancer and stem cell research, among other possible applications. But he soon realized he could use some help.
Improved 3D Printing for Patient-Specific Medical DiagnosisTBMG-297537/1/2018
What if you could hold a physical model of your own brain in your hands, accurate down to its every unique fold? That's just a normal part of life for Steven Keating, PhD, who had a baseball-sized tumor removed from his brain at age 26 while he was a graduate student in the MIT Media Lab's Mediated Matter Group. Curious to see what his brain actually looked like before the tumor was removed, and with the goal of better understanding his diagnosis and treatment options, Keating collected his medical data and began 3D printing his MRI and CT scans, but was frustrated that existing methods were prohibitively time-intensive and cumbersome and failed to accurately reveal important features of interest. Keating reached out to some of his group's collaborators, including members of the Wyss Institute at Harvard University, who were exploring a new method for 3D printing biological samples.
Imaging Flexible DNA ‘Building Blocks’ in 3-DTBMG-297337/1/2018
Over the past decade, researchers have been working to create nanoscale materials and devices using DNA as construction materials through a process called DNA origami. A single long “sca old” strand of DNA can be folded into specific shapes by hundreds of shorter strands, for example. The order of bases in each short strand acts as a blueprint that dictates the sca old DNA’s final 3-D shape.
An Overview of Microstructural Approaches for Modelling and Improving Sound Proofing Properties of Cellular Foams: Developments and Prospects2018-01-15646/13/2018
Significant advances have been made over the last 15 years in the field of modelling the acoustic properties of foams from the description of their microstructures. It entails a multidisciplinary work at the junction between physico-chemistry and mechanics of porous media, which involves a dialogue between different disciplines and requires the joint development of several techniques (imaging, upscaling, numerical computations, and experimental identification). It seems to be of timely interest to take stock of the methodological developments that have provided guidance on how to manufacture the new generation of foams with enhanced properties and to identify possible future methodological developments.
Perrot, Camille, Hoang, Minh Tan, Chevillotte, Fabien
Evaluating Electronics Contract Manufacturers for Medical DevicesTBMG-291006/1/2018
The ideal contract manufacturer is more than a transactional supplier; rather, it is a partner that improves the product and process. Printed circuit boards (PCBs) and electronic box build assemblies are critically important in the medical field. Today, most medical devices used in healthcare settings to diagnose, test, or treat patients, as well as devices critical to laboratory research, rely on PCBs in one way or another.
Characterization of Fabrication Induced Defects and Assessment of Their Effects on Integrity of Composite StructuresF-0074-2018-128235/14/2018
ABSTRACT Voids and ply waviness are the most common types of fabrication process induced defects in composite structures that can have detrimental effects on their load bearing capacity. To date, extensive works have been done on the characterization of fabrication induced defects on the mechanical properties of composites but less study has been performed to determine the effects of defects on the failure progression. Given the durability and damage tolerance requirements for certification and design of composite structures, it is important to evaluate the effects of these defects on the damage initiation and failure progression of a loaded composite structure. In this study, void and ply waviness information are extracted from X-ray computed tomography (CT) and optical microscopy and an efficient image-to-numerical solution is developed to map the detected voids and ply waviness into a finite element based progressive failure analysis model. An interlaminar tensile (ILT) test specimen under four point bending is used to demonstrate the capability of our response and progressive damage prediction.
Lua, Jim, Seneviratne, Waruna, Phan, Nam, Pham, Dinh, Sadeghirad, Alireza, Karuppiah, Anand, Cui, Xiaodong
Predicting Formation of Manufacturing Defects in Contoured CompositesF-0074-2018-128155/14/2018
ABSTRACT Composite helicopter rotor components are typically thick and often have areas with a tight radius of curvature, which make them especially prone to process-induced defects, including wrinkles and voids at ply interfaces. Such flaws cause high rejection rates in production of flight-critical components and structure. This work seeks to fill the gaps in understanding generation of the noted defects in contoured polymer-matrix composite (PMC) laminates. In particular, understanding and modelling defect formation at the early stages of the manufacturing process might be the missing link to enable the development of practical engineering solutions allowing for better control of the manufacturing process of contoured composite parts. In this work, an approach based on a continuum description of the uncured prepreg material, including the initial bulk or void content, and finite element modelling (FEM) is used to simulate the consolidation process at the early stages of manufacturing of contoured laminates. The simulation predicts instabilities leading to formation of both wrinkles and voids at ply interfaces during laminate debulking or vacuum consolidation. Applicability of the method to consolidation in both closed-cavity and open-face tooling is also demonstrated. FEM results show good correlation with X-ray Computed Tomography data. This work also introduces a new simulation concept based on finite element and discrete modelling of voids at ply interfaces to improve accuracy of predicting their evolution during the debulking operations.
Seon, Guillaume, Nikishkov, Yuri, Fergusson, Lauren, Makeev, Andrew
3D Imaging in SpaceTBMG-288875/1/2018
Technique Enables 3D Printing of MicrostructuresTBMG-288755/1/2018
Two-photon lithography (TPL), a high-resolution 3D printing technique, is capable of producing nanoscale features smaller than 1/100 the width of a human hair. The technique could enable X-ray computed tomography (CT) to analyze stress or defects noninvasively in embedded 3D-printed medical devices or implants.
Oak Ridge National LaboratoryTBMG-288745/1/2018
This year, Oak Ridge National Laboratory (ORNL) marks 75 years as a research institution. Located in Oak Ridge, TN, ORNL is the largest US Department of Energy science and energy laboratory, conducting basic and applied research to deliver transformative solutions to compelling problems in energy and security.
2021-12-29.TEST Shearographic Nondestructive Testing for High-Pressure Composite Tubes2018-01-12194/3/2018
In response to the need for lightweight design in industries, composite materials are increasingly used to replace traditional metal tubes. However, subsurface defects such as voids, delaminations, and microcracks are still remaining common issues in composite pressure tubes. This paper introduces an application of Digital Shearography method in the Non-Destructive Testing (NDT) of high-pressure composite tubes. A new prototype high-pressure composite tube with a working pressure of 1000 psi range is tested using the digital Shearography method. To detect the sub-surface defects, a reference Shearographic phase map is created at 0 psi state, after that the composite tube is pressured using an oil pump, then the second Shearographic phase map is created at the pressured state. By subtracting the two shearographic phase maps created in different pressure state, the sub-surface defects can be identified clearly. The Shearographic NDT result is then compared with CT scan result. The Shearographic NDT fundamentals, optimization of Shearographic NDT setup for high rigidity objects, experiment setup, and testing results are shown in detail in this paper.
Xie, Xin, Zhou, Zhou
The Effect of the Cell Shape on Compressive Mechanical Behavior of 3D Printed Extruded Cross-sections2018-01-13844/3/2018
Additive manufacturing has been a promising technique for producing sophisticated porous structures. The pore's architecture and infill density percentage can be easily controlled through additive manufacturing methods. This paper reports on development of sandwich-shape extruded cross sections with various architecture. These lightweight structures were prepared by employing additive manufacturing technology. In this study, three types of cross-sections with the same 2-D porosity were generated using particular techniques. a) The regular cross section of hexagonal honeycomb, b) the heterogeneous pore distribution of closed cell aluminum foam cross section obtained from image processing and c) linearly patterned topology optimized 2-D unit cell under compressive loading condition. The optimized unit cell morphology is obtained by using popular two-dimensional topology optimization code known as 99-line code, and by having the same volume fraction as the heterogeneous foam. The upper edge of the unit cell was under distributed uniform loading, and the lower edge was fixed. All the cross sections have the same cavity to wall area ratio on their 2-D configuration. The samples are extruded to produce 3-D CAD model of sandwich shape porous structures. The different samples are tested with universal compression machine and mechanical characteristics of the models are investigated. Furthermore, the energy absorption efficiency and load bearing capability of samples are studied. The results of the experimental procedure are compared to numerical simulations under quasi-static condition.
Raeisi, Sajjad, Tovar, Andres
Validation of Automated Prediction of Blood Product Needs Algorithm Processing Continuous Non-Invasive Vital Signs Streams (ONPOINT4)TBMG-287884/1/2018
Hemorrhagic shock occurs frequently in natural and man-made disaster scenarios. To control bleeding and to provide necessary resuscitation, swift and accurate diagnosis and decision-making are required. Early recognition of bleeding and the need for targeted interventions could improve both survival and resource management, allowing the receiving hospital to prepare required blood, surgeons, or other resources in advance of patient arrival and to conserve valuable resources in those patients who are not bleeding. Resources can be saved through avoidance of over-triage, thereby reducing unnecessary air transport, unnecessary blood transfusions, and unnecessary evaluation with labs, X-rays, and computed tomography scans, which is important in all resource-constrained and austere environments.
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