An Akron researcher is designing computer prediction models to test potential new docking seals that will better preserve breathable cabin air for astronauts living aboard the International Space Station and other NASA spacecraft.
Garafolo recently analyzed a two-piece elastic silicone – or elastomer – seal, using the IBM 1350 Glenn computer cluster at the Ohio Supercomputer Center (OSC). His model simulated air leakage through the elastomer, taking into account the effects of gas compressibility and variable permeability.
"Recent advances in both analytical and computational permeation evaluations in elastomer space seals offer the ability to predict the leakage of space seals," said Nicholas Garafolo, Ph.D., a research assistant professor in the College of Engineering at The University of Akron (UA). "Up until recently, the design of state-of-the-art space seals has relied heavily on intuition and costly experimental evaluations. My research evaluated the performance of the compressible permeation approach on a space seal candidate."
Garafolo serves on a research team tasked with testing polymer/metal seals being considered for future advanced docking and berthing systems. The university researchers work with partners in Cleveland, Ohio, at NASA's Glenn Research Center, which is responsible for developing the main interface seals for the new International Low Impact Docking System (iLIDS).
"For many years, Ohio industry has invested heavily in the aviation, aerospace and manufacturing sectors, which naturally led OSC to focus a portion of its computational resources on the field of advanced materials," said Ashok Krishnamurthy, interim co-executive director of the center. "Dr. Garafolo's work is an excellent example of how modeling and simulation often allows scientists to analyze materials in ways not possible through simple observation or physical experimentation."
NASA has been developing low-impact docking seals for manned missions to the International Space Station, as well as for future exploratory missions. Common to all docking systems, a main interface seal is mated to a metallic flange to provide the gas pressure seal.
"The two-piece seal system, for which experimental studies of seal performance are well documented, utilizes two elastomer bulbs, connected with a web and retained with a separate metallic ring," Garafolo explained. "Baseline referent leak rate experiments were performed with a multitude of pressure differentials. The prediction method consisted of a computational analysis of referent geometry with temperature and pressure boundary conditions."
To establish an analytical understanding of space seal leakage and construct their computational prediction tool, Garafolo and his colleagues modeled how air leaked into and through the elastomer seal, while taking into account the effects of gas compressibility and the variability of permeation on air pressure. The research team's first evaluations showed significant correlations between the experimental values and the computer modeled results.
For pressure differentials near operating conditions, the leak rates determined by the model accurately reflected the experimental results, within the bounds of uncertainty. For pressure differentials exceeding normal operating conditions, the differences between the experimental results and computational numbers were not quite as close, as expected. The larger differences in the leak rates, however, were attributed to extrapolation errors of the model parameters.
Garafolo and colleague Christopher C. Daniels, Ph.D., UA associate research professor in the College of Engineering, authored the paper, "An Evaluation of the Compressible Permeation Approach for Elastomeric Space Seals." It recently was published in the proceedings of the 50th Aerospace Sciences Meeting of the American Institute of Aeronautics and Astronautics, held in Nashville, Tenn., in January. The study was based upon work supported by NASA and through an allocation of computing time from OSC.
Jamie Abel | EurekAlert!
Strange but true: Turning a material upside down can sometimes make it softer
20.10.2017 | Universitat Autonoma de Barcelona
Metallic nanoparticles will help to determine the percentage of volatile compounds
20.10.2017 | Lomonosov Moscow State University
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Information Technology
20.10.2017 | Materials Sciences
20.10.2017 | Interdisciplinary Research