Search NASA⌕ Search

SEARCH · Search NASA

Results for “DESTRUCTION”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS2015

Non-destructive Evaluation of Bonds Between Fiberglass Composite and Metal

To assess the integrity and reliability of an adhesive joint in an automotive composite component, several non-destructive evaluation (NDE) methodologies are correlated to lap shear bond strengths. A glass-fabric-reinforced composite structure was bonded to a metallic structure with a two-part epoxy adhesive. Samples were subsequently cut and tested in shear, and flaws were found in some areas. This study aims to develop a reliable and portable NDE system for service-level adhesive inspection in the automotive industry. The results of the experimental investigation using several NDE methods are presented and discussed. Fiberglass-to-metal bonding is the ideal configuration for NDE via thermography using excitation with induction heating, due to the conductive metal and non-conductive glass-fiber-reinforced composites. Excitation can be either by a research-grade induction heater of highly defined frequency and intensity, or by a service-level heater, such as would be used for sealing windshields in a body shop. The thermographs thus produced can be captured via a high-resolution infrared camera, with principal component analysis and 2D spatial Laplacian processing. Alternatively, the thermographs can be captured by low resolution thermochromic microencapsulated liquid crystal film imaging, which needs no post-processing and can be very inexpensive. These samples were also examined with phased-array ultrasound. The NDE methods are compared to the lap shear values and to each other for approximate cost, accuracy, and time and level of expertise needed.

Zhao, Selina↗
NASA NTRS2016

Nitrous Oxides Ozone Destructiveness Under Different Climate Scenarios

Nitrous oxide (N2O) is an important greenhouse gas and ozone depleting substance as well as a key component of the nitrogen cascade. While emissions scenarios indicating the range of N2O's potential future contributions to radiative forcing are widely available, the impact of these emissions scenarios on future stratospheric ozone depletion is less clear. This is because N2O's ozone destructiveness is partially dependent on tropospheric warming, which affects ozone depletion rates in the stratosphere. Consequently, in order to understand the possible range of stratospheric ozone depletion that N2O could cause over the 21st century, it is important to decouple the greenhouse gas emissions scenarios and compare different emissions trajectories for individual substances (e.g. business-as-usual carbon dioxide (CO2) emissions versus low emissions of N2O). This study is the first to follow such an approach, running a series of experiments using the NASA Goddard Institute for Space Sciences ModelE2 atmospheric sub-model. We anticipate our results to show that stratospheric ozone depletion will be highest in a scenario where CO2 emissions reductions are prioritized over N2O reductions, as this would constrain ozone recovery while doing little to limit stratospheric NOx levels (the breakdown product of N2O that destroys stratospheric ozone). This could not only delay the recovery of the stratospheric ozone layer, but might also prevent a return to pre-1980 global average ozone concentrations, a key goal of the international ozone regime. Accordingly, we think this will highlight the importance of reducing emissions of all major greenhouse gas emissions, including N2O, and not just a singular policy focus on CO2.

stratospheric ozone depletion↗
NASA NTRS2017

Structure from Motion Photogrammetry and Micro X-Ray Computed Tomography 3-D Reconstruction Data Fusion for Non-Destructive Conservation Documentation of Lunar Samples

Our team is developing a modern, cross-disciplinary approach to documentation and preservation of astromaterials, specifically lunar and meteorite samples stored at the Johnson Space Center (JSC) Lunar Sample Laboratory Facility. Apollo Lunar Sample 60639, collected as part of rake sample 60610 during the 3rd Extra-Vehicular Activity of the Apollo 16 mission in 1972, served as the first NASA-preserved lunar sample to be examined by our team in the development of a novel approach to internal and external sample visualization. Apollo Sample 60639 is classified as a breccia with a glass-coated side and pristine mare basalt and anorthosite clasts. The aim was to accurately register a 3-dimensional Micro X-Ray Computed Tomography (XCT)-derived internal composition data set and a Structure-From-Motion (SFM) Photogrammetry-derived high-fidelity, textured external polygonal model of Apollo Sample 60639. The developed process provided the means for accurate, comprehensive, non-destructive visualization of NASA's heritage lunar samples. The data products, to be ultimately served via an end-user web interface, will allow researchers and the public to interact with the unique heritage samples, providing a platform to "slice through" a photo-realistic rendering of a sample to analyze both its external visual and internal composition simultaneously.

Beaulieu, K. R.↗
NASA NTRS2019

Computational Non-Destructive Evaluation Improving Ultrasonic Interrogation of Complex Geometry Composite Parts

Finite element simulation was employed in modeling the ultrasound (UT) pressure pulse propagation through a coupled liquid-composite medium to reproduce experimental data. From the simulation point of view, the proposed approach is challenging when there is a large simulation domain. For example, it is shown that a sub-micron wavelength of an ultrasonic wave requires a mesh size of several microns and this in turn requires significant computational resources, as well as special care in modeling. Some of the simulation results are presented considering that such modeling should reproduce experimental data for a healthy and faulty composite structure with complex geometry. Many possible experimental setups are simulated to demonstrate the non-destructive testing technique. This setup includes the generation of pressure pulse propagating through the tested composite plate and possible scattering by discontinuities (area of different impedance) that may be present in the panel. This scattered pulse together with the baseline pressure pulse generates a signature on the probe element which can be used to locate the position of defects in the structures.

modeling↗
NASA NTRSDate not supplied

Documentation of Destructive Analyses on Thin Sections in the US Antarctic Meteorite Collection

Detailed studies and analytical measurements are commonly made using thin sections of rocks affixed with epoxy to a slide. Thin sections [1,2] are a convenient medium in which to study rocks and meteorites, and fit into sample holders compatible with many instruments. Thin sections can also be used multiple times by different researchers, and many meteorite thin sections from the US Antarctic meteorite collection, have been utilized by 5 to 6 researchers over their 40 year lifetime. Thin sections are thus a scientifically valuable resource that must be preserved, documented and conserved over time. Analytical capabilities for meteorite and other sample studies have progressed extensively in the last 20 years, including many different kinds of analysis of high spatial resolution on thin sections. The progression to analysis on small samples has provided new and efficient ways to characterize samples while also preserving more material for future generations to study. While the development of analytical tools has expanded, many of these analyses are destructive in the sense that small pits or holes or other effects of the analysis are created on the thin sections. Preserving material for future generations thus requires recording the effects of multiple analyses on thin sections. Here we describe the process used for documenting the effects of various analyses on thin sections in the US Antarctic meteorite collection.

thin section↗
NASA NTRS2019

Reducing Aviation Fuel Costs with Non-Destructive Testing

Thermal barrier coatings (TBCs) are absolutely critical to the efficient and safe operation of gas turbine engines (GTEs). Manufacturing TBCs is a complex chemical, thermal and mechanical process that requires precise control. And yet, the variation in life of a TBC operated within a GTE is large. This variation ultimately reduces operational performance via a designed reduction to the turbine entry temperature, T4.This paper makes the case for developing advanced THz and sub-millimeter based nondestructive testing (NDT) techniques, capable of estimating when TBC components will fail. Such a technique could identify TBCs with low expected remaining useful lifetimes, directly after production. These TBCs could be re-manufactured, thereby not only improving their own expected useful life, but also the mean lifetime of the entire manufacturing population. A series of calculations demonstrates that TBCs with enhanced life characteristics can withstand higher T4 temperatures. Assuming that a GTE is to operate at a constant thrust, this increased temperature can be traded for a reduction in fuel flow. An analysis comparing fuel savings to manufacturing costs shows that substantial savings are achievable.

microwaves↗
NASA NTRS1966

Metal Oxide Silicon /MOS/ transistors protected from destructive damage by wire

Loop of flexible, small diameter, nickel wire protects metal oxide silicon /MOS/ transistors from a damaging electrostatic potential. The wire is attached to a music-wire spring, slipped over the MOS transistor case, and released so the spring tensions the wire loop around all the transistor leads, shorting them together. This allows handling without danger of damage.

Deboo, G. J.↗