Engineering topics
Publications and source records attributed to Burke, Eric.
NASA is providing key leadership in an international effort linking NASA and non-NASA resources to speed adoption of additive manufacturing (AM) to meet NASA's mission goals. Participants include industry, NASA's space partners, other government agencies, standards organizations and academia. Nondestructive Evaluation (NDE) is identified as a universal need for all aspects of additive manufacturing.
NASA is providing key leadership in an international effort linking NASA and non-NASA resources to speed adoption of additive manufacturing (AM) to meet NASA's mission goals. Participants include industry, NASA's space partners, other government agencies, standards organizations and academia. Nondestructive Evaluation (NDE) is identified as a universal need for all aspects of additive manufacturing.
The Heatshield for Extreme Entry Environment Technology (HEEET) Project is a NASA STMD (Space Technology Mission Directorate) and SMD (Science Mission Directorate) co-funded effort. The goal is to develop and mission infuse a new ablative Thermal Protection System that can withstand extreme entry. It is targeted to support NASA's high priority missions, as defined in the latest decadal survey, to destinations such as Venus and Saturn in-situ robotic science missions. Entry into these planetary atmospheres results in extreme heating. The entry peak heat-flux and associated pressure are estimated to be between one and two orders of magnitude higher than those experienced by Mars Science Laboratory or Lunar return missions. In the recent New Frontiers community announcement NASA has indicated that it is considering providing an increase to the PI (Principal Investigator) managed mission cost (PIMMC) for investigations utilizing the Heatshield for Extreme Entry Environment Technology (HEEET) and in addition, NASA is considering limiting the risk assessment to only their accommodation on the spacecraft and the mission environment.
NASA-STD-5009 requires that successful flaw detection by NDE methods be statistically qualified for use on fracture critical metallic components, but does not standardize practices. This task works towards standardizing calculations and record retention with a web-based tool, the NNWG POD Standards Library or NPSL. Test methods will also be standardized with an appropriately flexible appendix to -5009 identifying best practices. Additionally, this appendix will describe how specimens used to qualify NDE systems will be cataloged, stored and protected from corrosion, damage, or loss.
NDE historically has focused technology development in propagating wave phenomena with little attention to the field of electrostatics and emanating electric fields. This work is intended to bring electrostatic imaging to the forefront of new inspection technologies, and new technologies in general. The specific goals are to specify the electric potential and electric field including the electric field spatial components emanating from, to, and throughout volumes containing objects or in free space.
Microstructured optical fibers containing quantum dots scintillation material comprised of zinc sulfide nanocrystals doped with magnesium sulfide are presented. These quantum dots are applied inside the microstructured optical fibers using capillary action. The x-ray photon counts of these fibers are compared to the output of a collimated CdTe solid state detector over an energy range from 10 to 40 keV. The results of the fiber light output and associated effects of an acrylate coating and the quantum dot application technique are discussed.
This presentation describes efforts at NASA Langley Research Center to develop methodologies for autonomous detection of flaws in NDE (Nondestructive Evaluation) data.
Scintillation is the process currently employed by conventional x-ray detectors to create x-ray images. Scintillating quantum dots or nano-crystals (StQDs) are a novel, nanometer-scale material that upon excitation by x-rays, re-emit the absorbed energy as visible light. StQDs theoretically have higher output efficiency than conventional scintillating materials and are more environmental friendly. This paper will present the characterization of several critical elements in the use of StQDs that have been performed along a path to the use of this technology in wide spread x-ray imaging. Initial work on the SQDIX system has shown great promise to create state-of-the-art sensors using StQDs as a sensor material. In addition, this work also demonstrates a high degree of promise using StQDs in microstructured fiber optics. Using the microstructured fiber as a light guide could greatly increase the capture efficiency a StQDs based imaging sensor.
No abstract available
The current activities in the National Aeronautics and Space Administration Nondestructive Evaluation (NDE) Program are presented. The topics covered include organizational communications, orbital weld inspection, electric field imaging, fracture critical probability of detection validation, monitoring of thermal protection systems, physical and document standards, image quality indicators, integrity of composite pressure vessels, and NDE for additively manufactured components.
(1) General Rationale for Additive Manufacturing (AM): (a) Operate under a 'design-to-constraint' paradigm, make parts too complicated to fabricate otherwise, (b) Reduce weight by 20 percent with monolithic parts, (c) Reduce waste (green manufacturing), (e) Eliminate reliance on Original Equipment Manufacturers for critical spares, and (f) Extend life of in-service parts by innovative repair methods; (2) NASA OSMA NDE of AM State-of-the-Discipline Report; (3) Overview of NASA AM Efforts at Various Centers: (a) Analytical Tools, (b) Ground-Based Fabrication (c) Space-Based Fabrication; and (d) Center Activity Summaries; (4) Overview of NASA NDE data to date on AM parts; and (5) Gap Analysis/Recommendations for NDE of AM.
The quality of images generated during an infrared thermal inspection depends on many system variables, settings, and parameters to include the focal length setting of the IR camera lens. If any relevant parameter is incorrect or sub-optimal, the resulting IR images will usually exhibit inherent unsharpness and lack of resolution. Traditional reference standards and image quality indicators (IQIs) are made of representative hardware samples and contain representative flaws of concern. These standards are used to verify that representative flaws can be detected with the current IR system settings. However, these traditional standards do not enable the operator to quantify the quality limitations of the resulting images, i.e. determine the inherent maximum image sensitivity and image resolution. As a result, the operator does not have the ability to optimize the IR inspection system prior to data acquisition. The innovative IQI described here eliminates this limitation and enables the operator to objectively quantify and optimize the relevant variables of the IR inspection system, resulting in enhanced image quality with consistency and repeatability in the inspection application. The IR IQI consists of various copper foil features of known sizes that are printed on a dielectric non-conductive board. The significant difference in thermal conductivity between the two materials ensures that each appears with a distinct grayscale or brightness in the resulting IR image. Therefore, the IR image of the IQI exhibits high contrast between the copper features and the underlying dielectric board, which is required to detect the edges of the various copper features. The copper features consist of individual elements of various shapes and sizes, or of element-pairs of known shapes and sizes and with known spacing between the elements creating the pair. For example, filled copper circles with various diameters can be used as individual elements to quantify the image sensitivity limit. Copper line-pairs of various sizes where the line width is equivalent to the spacing between the lines can be used as element-pairs to quantify the image resolution limit.