Data processing: measuring – calibrating – or testing – Measurement system in a specific environment – Mechanical measurement system
Reexamination Certificate
2003-09-08
2004-08-10
Hoff, Marc S. (Department: 2857)
Data processing: measuring, calibrating, or testing
Measurement system in a specific environment
Mechanical measurement system
C703S014000
Reexamination Certificate
active
06775625
ABSTRACT:
BACKGROUND OF INVENTION
The invention relates generally to nondestructive methods for determining the integrity of components and structures. More particularly, the invention is a method and system for nondestructive test method qualification and probability of detection determination, for establishing and maintaining nondestructive testing proficiency of inspectors, for periodically presenting flaw signals to inspectors during routine inspections, and for ensuring sufficient scan coverage for detection of material defects in a test piece. The invention finds use in general nondestructive testing as well as where eddy current and ultrasound methods are used to detect the presence of flaws in components and structures.
Nondestructive testing (NDT) is used in many industries to detect the presence of flaws so that the integrity of components and structures may be determined. NDT involves using various test methods, such as eddy current and ultrasonics. Applications include military and civilian aircraft, fossil and nuclear electrical power generation equipment, petrochemical plants, etc. There are several needs within the NDT environment that, if satisfied, would significantly reduce inspection costs and improve the reliability and quality of inspections.
NDT method qualification and probability of detection (POD) determination is one area of need. Demonstration of the capability and reliability of new NDT techniques must often be done in a short period of time and at minimal cost. The present approach is to perform a POD study. These studies involve producing many test specimens with realistic flaws, training multiple NDT technicians, and conducting blind tests. Fabrication of the flawed specimens is very expensive and time consuming. As a result, a POD study is usually performed only for the most critical applications. A system and method to reduce costs and time required to implement POD studies is needed.
NDT inspectors must be trained to ensure proficiency in new and existing NDT procedures. Training is also required periodically in order to maintain proficiency of the inspectors through practice. Although specimens with realistic flaws are needed for training, they are often not available. Video-based training courses are available, but they do not provide “hands-on” experience with real flaws. Therefore, better training methods are another area of need.
Monitoring existing inspections when flaws are infrequent presents another area of need. In some routine inspections, flaws are encountered very infrequently, sometimes less than once per year. Inspectors may become conditioned to not expecting flaws, resulting in a loss of proficiency. A method is needed to periodically present simulated flaws to inspectors during routine inspections.
Ensuring that a thorough scan is conducted over an entire test piece in another area of need. Some inspections are performed by hand scanning, and the scanning coverage of the appropriate area is dependent on the skill and attention of the operator. A method is needed to monitor scan position so that proper coverage is obtained.
SUMMARY OF INVENTION
The present invention provides for a system and method that satisfies the needs for reducing costs and time required to implement POD studies, providing improved realistic training methods, presenting simulated flaws to inspectors during routine inspections, and for monitoring scan position to ensure proper coverage of test pieces. This invention performs the functions of an NDT inspection simulator analogous to flight simulators used to train aircraft pilots. The operations of the NDT simulator are transparent to the inspector using the system when realistic, virtual flaw signals are presented at preprogrammed locations on the actual test piece. The virtual flaw signals may be premeasured or generated from a model. This method of presenting virtual flaws provides the equivalent of real flaws to an inspector without the requirement for having actual flaws in a test piece. The inspector may use the same probes and instrumentation of a conventional NDT instrument that are normally used in the inspection process. The simulator may be connected between the probe and NDT instrument so that flaw responses will be injected into the instrument, and the operator may view a response on the actual NDT instrument display. The probe and instrument may remain “live”, so that the interaction between the probe and the test piece remain active as well. The simulator may track the probe position so that responses from flaws can be injected at a selected location on the test piece.
The present invention enables POD tests to be accomplished without the need for manufacturing a large number of actually flawed test pieces. A training mode may be implemented in which the inspector receives instructions from the system and can practice with the equivalent of actual flawed test pieces. The system may be used with routine inspections to inject artificial flaw signals to keep inspectors alert, and may be used to monitor probe position in manual test scans to ensure proper coverage.
In another embodiment of the present invention, instead of injecting virtual flaws into a test instrument, the present invention may accept an output signal from an NDT test instrument, add virtual flaws to this signal within the system, and display the results on a computer monitor. This embodiment provides a virtual instrument for an inspector, who may view the computer monitor instead of the test instrument for conducting nondestructive tests.
An embodiment of the present is a method for nondestructive testing with flaw simulation, comprising the steps for storing a geometry of a test piece and a positional map of virtual flaw signals for the test piece in a control computer, causing a nondestructive testing probe to scan a test piece by movement of the probe over the test piece by an inspector, tracking nondestructive testing probe positions with respect to the test piece and sending probe position signals to the control computer, processing nondestructive testing probe output signals and displaying the processed signals to the inspector, injecting virtual flaw signals into the processed probe output signals based on the probe positions, the stored test piece geometry and the stored positional map for determining virtual flaw response signals, and displaying the virtual flaw response signals to the inspector. The steps for processing probe output signals and injecting virtual flaw signals may comprise the steps for sending excitation signals to the probe from conventional nondestructive test instrumentation through a virtual flaw signal injection circuit, receiving the probe output signals by a virtual flaw signal injection circuit, computing virtual flaw signals by the control computer based on the probe positions, the stored geometry of the test piece and the stored positional map of virtual flaw signals for the test piece, combining the probe output signals and the virtual flaw signals from the control computer by the virtual flaw signal injection circuit for determining the virtual flaw response signals, and sending the virtual flaw response signals from the virtual flaw signal injection circuit to the conventional nondestructive test instrumentation for displaying the virtual flaw response signals to the inspector by the conventional nondestructive test instrumentation. The method may further comprise sensing nondestructive testing probe liftoff from the test piece, sending probe liftoff signals to the control computer, and using the probe liftoff signals for computing virtual flaw signals. The steps for processing probe output signals and injecting virtual flaw signals may comprise the steps for sending excitation signals to the probe and receiving the probe output signals by conventional nondestructive test instrumentation, receiving output signals from the conventional nondestructive test instrumentation by the control computer, computing virtual flaw signals by the control computer based on the probe positions, the probe liftoff si
Burkhardt Gary L.
Fisher Jay L.
Peterson Eric C.
Hoff Marc S.
Raymond Edward
Southwest Research Institute
Taylor Russell & Russell P.C.
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