Process compensated resonant testing (PCRT) is a full body nondestructive evaluation (NDE) method that measures the resonance frequencies of a part and correlates them to the part’s material state, structural integrity, or damage state. This paper describes the quantification of creep damage in a virtual part population via the correlation of PCRT parameters to creep strain using inversion methods and vibrational pattern recognition (VIPR) analysis. Modeled populations were created using the finite element method (FEM) for single crystal (SX) nickel-based superalloy dogbone and turbine engine airfoil geometries. The modeled populations include nominal variation in crystallographic orientation, geometric dimensions, and material properties. Modeled populations also include parts with variable levels of creep strain, allowing for NDE sensitivity studies. FEM model inversion tools quantified creep strain and distinguished it from other variations in the part populations. Resonant modes that were found to be particularly sensitive to creep strain were evaluated using VIPR algorithms to correlate and quantify creep strain with PCRT metrics. The results for PCRT forward models, model inversion, and VIPR correlations were verified with experimental creep strain measurements made for dogbone specimens. This verification demonstrated that PCRT inspections can be trained through forward models to detect and quantify creep damage in a part.

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