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Title: Accelerated Life Structural Benchmark Testing for a Stirling Convertor Heater Head

Abstract

For proposed long-duration NASA Space Science missions, the Department of Energy, Lockheed Martin, Infinia Corporation, and NASA Glenn Research Center are developing a high-efficiency, 110-watt Stirling Radioisotope Generator (SRG110). A structurally significant limit state for the SRG110 heater head component is creep deformation induced at high material temperature and low stress level. Conventional investigations of creep behavior adequately rely on experimental results from uniaxial creep specimens, and a wealth of creep data is available for the Inconel 718 material of construction. However, the specified atypical thin heater head material is fine-grained with a heat treatment that limits precipitate growth, and little creep property data for this microstructure is available in the literature. In addition, the geometry and loading conditions apply a multiaxial stress state on the component, far from the conditions of uniaxial testing. For these reasons, an extensive experimental investigation is ongoing to aid in accurately assessing the durability of the SRG110 heater head. This investigation supplements uniaxial creep testing with pneumatic testing of heater head-like pressure vessels at design temperature with stress levels ranging from approximately the design stress to several times that. This paper presents experimental results, post-test microstructural analyses, and conclusions for four higher-stress, accelerated lifemore » tests. Analysts are using these results to calibrate deterministic and probabilistic analytical creep models of the SRG110 heater head.« less

Authors:
 [1];  [2]
  1. National Aeronautics and Space Administration, Glenn Research Center, Cleveland, OH 44135 (United States)
  2. Ohio Aerospace Institute, NASA Glenn Research Center, Cleveland, OH 44135 (United States)
Publication Date:
OSTI Identifier:
20798009
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 813; Journal Issue: 1; Conference: 10. conference on thermophysics applications in microgravity; 23. symposium on space nuclear power and propulsion; 4. conference on human/robotic technology and the national vision for space exploration; 4. symposium on space colonization; 3. symposium on new frontiers and future concepts, Albuquerque, NM (United States), 12-16 Feb 2006; Other Information: DOI: 10.1063/1.2169243; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BENCHMARKS; CREEP; DEFORMATION; EFFICIENCY; HEAT TREATMENTS; HEATERS; INCONEL 718; MICROSTRUCTURE; NASA; PERFORMANCE; PRESSURE VESSELS; PROBABILISTIC ESTIMATION; RADIOISOTOPE GENERATORS; RADIOISOTOPES; STIRLING ENGINES; STRESSES; TESTING; THERMOELECTRIC GENERATORS; NESDPS Office of Nuclear Energy Space and Defense Power Systems

Citation Formats

Krause, David L., and Kantzos, Pete T.. Accelerated Life Structural Benchmark Testing for a Stirling Convertor Heater Head. United States: N. p., 2006. Web. doi:10.1063/1.2169243.
Krause, David L., & Kantzos, Pete T.. Accelerated Life Structural Benchmark Testing for a Stirling Convertor Heater Head. United States. doi:10.1063/1.2169243.
Krause, David L., and Kantzos, Pete T.. Fri . "Accelerated Life Structural Benchmark Testing for a Stirling Convertor Heater Head". United States. doi:10.1063/1.2169243.
@article{osti_20798009,
title = {Accelerated Life Structural Benchmark Testing for a Stirling Convertor Heater Head},
author = {Krause, David L. and Kantzos, Pete T.},
abstractNote = {For proposed long-duration NASA Space Science missions, the Department of Energy, Lockheed Martin, Infinia Corporation, and NASA Glenn Research Center are developing a high-efficiency, 110-watt Stirling Radioisotope Generator (SRG110). A structurally significant limit state for the SRG110 heater head component is creep deformation induced at high material temperature and low stress level. Conventional investigations of creep behavior adequately rely on experimental results from uniaxial creep specimens, and a wealth of creep data is available for the Inconel 718 material of construction. However, the specified atypical thin heater head material is fine-grained with a heat treatment that limits precipitate growth, and little creep property data for this microstructure is available in the literature. In addition, the geometry and loading conditions apply a multiaxial stress state on the component, far from the conditions of uniaxial testing. For these reasons, an extensive experimental investigation is ongoing to aid in accurately assessing the durability of the SRG110 heater head. This investigation supplements uniaxial creep testing with pneumatic testing of heater head-like pressure vessels at design temperature with stress levels ranging from approximately the design stress to several times that. This paper presents experimental results, post-test microstructural analyses, and conclusions for four higher-stress, accelerated life tests. Analysts are using these results to calibrate deterministic and probabilistic analytical creep models of the SRG110 heater head.},
doi = {10.1063/1.2169243},
journal = {AIP Conference Proceedings},
number = 1,
volume = 813,
place = {United States},
year = {Fri Jan 20 00:00:00 EST 2006},
month = {Fri Jan 20 00:00:00 EST 2006}
}
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