Abstract: A nondestructive method for a volumetric examination of a blade root of a turbine blade while the turbine blade is installed in a turbine shaft of a steam turbine includes attaching a bracket to the turbine blade, the bracket conforming to the geometry of the turbine blade, positioning an ultrasonic phased array probe within a slot formed in the bracket to enable the probe to translate along the geometry of the turbine blade to a desired position for generation of a scan of a portion of the blade root, generating a scan of the desired position by directing ultrasonic waves via the ultrasonic phased array probe, and capturing reflected ultrasonic waves by a receiver to generate the scan and comparing the scan to a reference scan of the blade root to determine defects within the blade root.

Abstract: A method for scanning a weld buildup formed on a circumferential portion of a disc for a steam turbine. The method includes providing an ultrasound probe for generating at least one ultrasound beam sweep. The circumferential portion is scanned with a first beam sweep oriented in a first beam orientation to detect a first flaw type in the weld buildup. The circumferential portion is also scanned with a second beam sweep oriented in a second beam orientation to detect a second flaw type in the weld buildup. Further, the circumferential portion is scanned with a third beam sweep oriented in a third beam orientation to detect a third flaw type in the weld buildup. The method also includes rotating the disc about a disc axis during scanning of the circumferential portion and moving the first, second and third beam sweeps in a direction parallel to the disc axis during scanning.

Abstract: System, methods, and devices for inspecting generator rotor slot wedges in-situ are provided. The system includes a controller operably connected to a remote-control carriage for transmitting control signals and receiving data. The carriage includes a drive module for moving the carriage into an inspection area, e.g., through an air gap between the rotor and stator, and an inspection module operable to inspect a rotor wedge surface. The inspection module includes a jack assembly and a transducer assembly. The jack assembly is operably connected to the transducer assembly, and configured to elevate the transducer assembly to the rotor wedge surface for inspection.

Abstract: A method and software system for flaw identification, grouping and sizing for fatigue life assessment for rotors used in turbines and generators. The method includes providing ultrasonic data of a plurality of rotor slices and providing volume reconstruction of the ultrasonic data. The method also includes providing in-slice identification, grouping and sizing of flaw indications in the rotor based on the volume reconstruction. Further, the method includes providing inter-slice identification, grouping and sizing of the flaw indications based on the in-slice flaw indications and providing flaw location and size information. The method can be used in both phased-array and A-scan inspections.

Abstract: A method for probabilistic fatigue life prediction using nondestructive testing data considering uncertainties from nondestructive examination (NDE) data and fatigue model parameters. The method utilizes uncertainty quantification models for detection, sizing, fatigue model parameters and inputs. A probability of detection model is developed based on a log-linear model coupling an actual flaw size with a nondestructive examination (NDE) reported size. A distribution of the actual flaw size is derived for both NDE data without flaw indications and NDE data with flaw indications by using probabilistic modeling and Bayes theorem. A turbine rotor example with real world NDE inspection data is presented to demonstrate the overall methodology.

Abstract: System, methods, and devices for inspecting generator rotor slot wedges in-situ are provided. The system includes a controller operably connected to a remote-control carriage for transmitting control signals and receiving data. The carriage includes a drive module for moving the carriage into an inspection area, e.g., through an air gap between the rotor and stator, and an inspection module operable to inspect a rotor wedge surface. The inspection module includes a jack assembly and a transducer assembly. The jack assembly is operably connected to the transducer assembly, and configured to elevate the transducer assembly to the rotor wedge surface for inspection.

Abstract: Immersion ultrasonic NDE is performed within cavities of inanimate objects, having downwardly directed openings, such as for in situ inspection of steam inlet sleeves and steam inlet necks within steam turbine housings. A shaft assembly has one or more single angle or phased array ultrasonic probes that are affixed on an upstream or distal end. An inflatable bladder is affixed to the shaft on a proximal end of the shaft assembly downstream the ultrasonic probe(s). The shaft is inserted into the cavity opening, and the bladder is inflated to form a fluid tight seal against the cavity. Immersion fluid is introduced upstream the bladder in the volume occupied by the probes. Immersion ultrasonic inspection of the object is then performed.

Abstract: A method for scanning a weld buildup formed on a circumferential portion of a disc for a steam turbine. The method includes providing an ultrasound probe for generating at least one ultrasound beam sweep. The circumferential portion is scanned with a first beam sweep oriented in a first beam orientation to detect a first flaw type in the weld buildup. The circumferential portion is also scanned with a second beam sweep oriented in a second beam orientation to detect a second flaw type in the weld buildup. Further, the circumferential portion is scanned with a third beam sweep oriented in a third beam orientation to detect a third flaw type in the weld buildup. The method also includes rotating the disc about a disc axis during scanning of the circumferential portion and moving the first, second and third beam sweeps in a direction parallel to the disc axis during scanning.

Abstract: Immersion ultrasonic NDE is performed within cavities of inanimate objects, having downwardly directed openings, such as for in situ inspection of steam inlet sleeves and steam inlet necks within steam turbine housings. A shaft assembly has one or more single angle or phased array ultrasonic probes that are affixed on an upstream or distal end. An inflatable bladder is affixed to the shaft on a proximal end of the shaft assembly downstream the ultrasonic probe(s). The shaft is inserted into the cavity opening, and the bladder is inflated to form a fluid tight seal against the cavity. Immersion fluid is introduced upstream the bladder in the volume occupied by the probes. Immersion ultrasonic inspection of the object is then performed.

Abstract: An industrial ultrasonic inspection system is capable of scanning for discontinuities in relatively thick solid objects such as solid core steel alloy turbine shafts. A phased array probe located on the turbine shaft periphery transmits ultrasonic pulses in a sector-shaped scanning field within the shaft that includes the inner 50% core volume that is of special interest in non-destructive evaluation and inspection. Staggered pulse firing alone or in combination with variable pulse repetition frequency (PRF) may be utilized in order to balance image quality with inspection speed. Discontinuities are identified by analysis of reflected echo waveform energy. Discontinuity size and position within the inspected object is correlated with an equivalent reflector size (ERS) by the Distance-Gain-Size (DGS) method.

Abstract: A method for probabilistic fatigue life prediction using nondestructive testing data considering uncertainties from nondestructive examination (NDE) data and fatigue model parameters. The method utilizes uncertainty quantification models for detection, sizing, fatigue model parameters and inputs. A probability of detection model is developed based on a log-linear model coupling an actual flaw size with a nondestructive examination (NDE) reported size. A distribution of the actual flaw size is derived for both NDE data without flaw indications and NDE data with flaw indications by using probabilistic modeling and Bayes theorem. A turbine rotor example with real world NDE inspection data is presented to demonstrate the overall methodology.

Abstract: A method and software system for flaw identification, grouping and sizing for fatigue life assessment for rotors used in turbines and generators. The method includes providing ultrasonic data of a plurality of rotor slices and providing volume reconstruction of the ultrasonic data. The method also includes providing in-slice identification, grouping and sizing of flaw indications in the rotor based on the volume reconstruction. Further, the method includes providing inter-slice identification, grouping and sizing of the flaw indications based on the in-slice flaw indications and providing flaw location and size information. The method can be used in both phased-array and A-scan inspections.

Abstract: An image reconstruction method includes receiving volume data comprising a plurality of sampling points, determining a first conditioning of the sampling points suppressing low amplitudes and conserving maximum amplitudes, determining a second conditioning of the sampling points wherein an influence of a sampling point depends on its distance to a grid point in a sampling grid, determining a kernel comprising a plurality of weighting functions for the first conditioning and the second conditioning to determine an energy spread of each of the plurality of sampling points without determining a shape or size of the kernel, and outputting a reconstructed volume according to the energy spread of each of the plurality of sampling points.

Abstract: An industrial ultrasonic inspection system is capable of scanning for discontinuities in relatively thick solid objects such as solid core steel alloy turbine shafts. A phased array probe located on the turbine shaft periphery transmits ultrasonic pulses in a sector-shaped scanning field within the shaft that includes the inner 50% core volume that is of special interest in non-destructive evaluation and inspection. Staggered pulse firing alone or in combination with variable pulse repetition frequency (PRF) may be utilized in order to balance image quality with inspection speed. Discontinuities are identified by analysis of reflected echo waveform energy. Discontinuity size and position within the inspected object is correlated with an equivalent reflector size (ERS) by the Distance-Gain-Size (DGS) method.

Abstract: A method and apparatus for three-dimensional visualization and analysis for automatic non-destructive examination of a solid Rotor using ultrasonic phased array is disclosed. Data is acquired by scanning a solid rotor with a phased array ultrasound transducer producing a plurality of two dimensional ultrasound scans. Each of a plurality of sample points of a plurality of two dimensional ultrasound scans are associated with a corresponding 3D image point of a regular grid. A kernel function for each of the plurality of sample points defining a size and shape of a kernel located at the corresponding image point is determined. A weight is assigned to each kernel which, in one embodiment, is based on the sample point value. A value for each image point of the regular 3D grid is determined based on kernels overlapping each image point. A three-dimensional volume representing the solid rotor is then visualized.

Abstract: An image reconstruction method includes receiving volume data comprising a plurality of sampling points, determining a first conditioning of the sampling points suppressing low amplitudes and conserving maximum amplitudes, determining a second conditioning of the sampling points wherein an influence of a sampling point depends on its distance to a grid point in a sampling grid, determining a kernel comprising a plurality of weighting functions for the first conditioning and the second conditioning to determine an energy spread of each of the plurality of sampling points without determining a shape or size of the kernel, and outputting a reconstructed volume according to the energy spread of each of the plurality of sampling points.

Abstract: A method and apparatus for three-dimensional visualization and analysis for automatic non-destructive examination of a solid Rotor using ultrasonic phased array is disclosed. Data is acquired by scanning a solid rotor with a phased array ultrasound transducer producing a plurality of two dimensional ultrasound scans. Each of a plurality of sample points of a plurality of two dimensional ultrasound scans are associated with a corresponding 3D image point of a regular grid. A kernel function for each of the plurality of sample points defining a size and shape of a kernel located at the corresponding image point is determined. A weight is assigned to each kernel which, in one embodiment, is based on the sample point value. A value for each image point of the regular 3D grid is determined based on kernels overlapping each image point. A three-dimensional volume representing the solid rotor is then visualized.