Advanced Stirling Convertor Heater Head Durability and Reliability Quantification

Experimental Creep Life Assessment for the Advanced Stirling Convertor Heater Head

“…The third step of the life assessment approach is a probabilistic analysis (Ref. 7) to evaluate uncertainties in a) the GRC uniaxial creep test data, b) the design parameters, and c) the operating conditions of the heater head, to determine if the three creep criteria are met with a minimum reliability level of 0.999.…”

“…The life assessment also includes probabilistic reliability analysis, which evaluates the heater head reliability dependent on uncertainties in wall thickness due to manufacturing variations, in the working gas pressure due to measurement and control, and in the creep properties of the material itself based on the GRC creep test results (Ref. 7).…”

Structural Benchmark Creep Testing for the Advanced Stirling Convertor Heater Head

“…This probabilistic assessment (ref. 7) simulates and analyzes uncertainties in the uniaxial creep test data, design parameters, and operating conditions of the heater head. Again, it must show positive margins on the same three creep criteria to ensure a minimum reliability level of 0.999.…”

“…The second phase analysis uses a master curve creep model (ref. 7) for the MarM-247 material; the model is developed from the GRC uniaxial creep test results of MarM-247 and will be updated as additional creep test results become available. This timedomain analysis provides the median creep response of the heater head structure at important time increments, including the increment at the 17-year lifetime requirement, where it must show positive margins for the three creep criteria.…”

Supporting Technology at GRC to Mitigate Risk as Stirling Power Conversion Transitions to Flight

“…The present analysis for the ASC-E2 heater head made from MarM-247, as it would operate in an ASRG, is more complete as it does include all of the internal and external heat exchangers, residual stresses from manufacturing, and the preload applied from system integration. 13,14 Structural benchmark testing of heater head shells will be conducted to validate analytical models and to complement the uniaxial creep testing of MarM-247. 15 During benchmark testing, the heater head will experience multi-axial stresses similar to what exists during operation in a generator.…”