Patent ID: 11946883
Assignee: UNITED STATES AS REPRESENTED BY THE ADMINISTRATOR OF NASA
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A method for qualifying a radiographic inspection system in a selected set-up to make a crack detectability determination, the method comprising:
performing a computer-simulated process comprising:
selecting a simulated crack comprising a target flaw size;
selecting a simulated crack-like flaw comprising a calibration flaw size;
performing a first simulation test on the simulated crack and a second simulation test on the simulated crack-like flaw using a simulated radiographic system in the selected set-up;
determining one or more simulated output parameters based upon the first and second simulation tests, wherein the one or more simulated output parameters include one or more simulated crack output parameters and one or more simulated crack-like flaw output parameters;
determining a simulated contrast-to-noise ratio sensitivity function (CNR SF) based upon the one or more simulated output parameters; and
determining one or more simulated transfer functions between the target flaw size and the calibration flaw size based on the CNR SF;

performing an empirical process comprising:
selecting a real crack specimen comprising the target flaw size;
selecting an empirical image quality indicator (IQI) comprising a crack-like flaw having the calibration flaw size;
performing a first empirical test on the real crack specimen and a second empirical test on the empirical IQI using the radiographic inspection system in the selected set-up;
determining one or more empirical output parameters based upon the first and second empirical tests, wherein the one or more empirical output parameters include one or more real crack specimen output parameters and one or more empirical IQI output parameters;
determining an empirical CNR SF based upon the one or more empirical output parameters; and
determining one or more empirical transfer functions between the target flaw size and the calibration flaw size based on the empirical CNR SF;

determining a plurality of correlations based upon the simulated CNR SF and the empirical CNR SF;
determining a predicted CNR SF for crack detection based upon the plurality of correlations;
selecting and qualifying an inspection IQI for a predetermined target flaw size for use in the radiographic inspection system in the selected set-up based upon the plurality of correlations and the predicted CNR SF;
determining minimum qualified values for the one or more empirical IQI output parameters for the inspection IQI to provide detection of the predetermined target flaw size;
performing an inspection process comprising:
selecting the qualified inspection IQI for the predetermined target flaw size;
performing an inspection test on the qualified inspection IQI using the radiographic inspection system in the selected set-up;
determining one or more inspection output parameters; and
verifying that the one or more inspection output parameters meet or exceed the minimum qualified values to qualify the radiographic inspection system in the selected set-up; and

inspecting a component part using the qualified radiographic inspection system in the selected set-up to detect one or more cracks with greater than or equal to the predetermined target flaw size.