Patent Application
20180238755
The present disclosure relates generally to methods for monitoring component strain, methods for making components with integral strain indicators, and components having integral strain indicators.
Throughout various industrial applications, apparatus components are subjected to numerous extreme conditions (e.g., high temperatures, high pressures, large stress loads, etc.). Over time, an apparatus's individual components may suffer creep and/or deformation that may reduce the component's usable life. Such concerns might apply, for instance, to some turbomachines.
Turbomachines are widely utilized in fields such as power generation and aircraft engines. For example, a conventional gas turbine system includes a compressor section, a combustor section, and at least one turbine section. The compressor section is configured to compress a working fluid (e.g., air) as the working fluid flows through the compressor section. The compressor section supplies a high pressure compressed working fluid to the combustors where the high pressure working fluid is mixed with a fuel and burned in a combustion chamber to generate combustion gases having a high temperature and pressure. The combustion gases flow along a hot gas path into the turbine section. The turbine section utilizes the combustion gases by extracting energy therefrom to produce work. For example, expansion of the combustion gases in the turbine section may rotate a shaft to power the compressor, an electrical generator, and other various loads.
During operation of a turbomachine, various components within the turbomachine and particularly components along the hot gas path such as turbine blades within the turbine section of the turbomachine, may be subject to creep due to high temperatures and stresses. For turbine blades, creep may cause portions of or the entire blade to elongate so that the blade tips contact a stationary structure, for example a turbine casing, and potentially cause unwanted vibrations and/or reduced performance during operation.
Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
In accordance with one embodiment of the present disclosure, a method of making a component is provided. The method includes forming the component, the component including an internal volume including a first material and an outer surface. The method further includes directly depositing a plurality of fiducial markers on the outer surface, the fiducial markers including a second material that is compatible with the first material. The plurality of fiducial markers form a passive strain indicator, the passive strain indicator including an analysis region, a locator region, and a serial region. At least one of the plurality of fiducial markers is deposited in each of the analysis region, the locator region, and the serial region.
In accordance with another embodiment of the present disclosure, a component is provided. The component includes a component body including an internal volume including a first material and an outer surface. The component further includes a passive strain indicator provided on an outer surface of the component body. The passive strain indicator includes an analysis region, a locator region, and a serial region. The passive strain indicator further includes a plurality of fiducial markers directly deposited on the outer surface, the fiducial markers including a second material that is compatible with the first material. At least one of the plurality of fiducial markers is deposited in each of the analysis region, the locator region, and the serial region.
In accordance with another embodiment of the present disclosure, a method of monitoring a component is provided. The component includes an internal volume including a first material and an outer surface. The method includes initially directly measuring a plurality of fiducial markers on a portion of the outer surface of the component with a three-dimensional data acquisition device, and creating a three-dimensional model of the component based on the initial direct measurement. The method further includes subjecting the component to at least one duty cycle. The method further includes subsequently directly measuring the plurality of fiducial markers after the at least one duty cycle with the three-dimensional data acquisition device, and creating a three-dimensional model of the component based on the subsequent direct measurement. The method further includes comparing the three-dimensional model based on the initial direct measurement to the three-dimensional model based on the subsequent direct measurement. The plurality of fiducial markers are directly deposited on the portion of the outer surface of the component and the fiducial markers include a second material compatible with the first material. The plurality of fiducial markers form a passive strain indicator, the passive strain indicator including an analysis region, a locator region, and a serial region, wherein at least one of the plurality of fiducial markers is deposited in each of the analysis region, the locator region, and the serial region.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:
Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
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The passive strain indicator 40 may comprise a variety of different configurations and cross-sections such as by incorporating a variety of differently shaped, sized, and positioned fiducial markers 12. For example, the strain sensor 40 may comprise a variety of different fiducial markers 12 comprising various shapes and sizes. Such embodiments may provide for a greater variety of distance measurements 48. The greater variety may further provide a more robust strain analysis on a particular portion of the component 10 by providing strain measurements across a greater variety of locations.
Furthermore, the values of various dimensions of the passive strain indicator 40 may depend on, for example, the component 10, the location of the passive strain indicator 40, the targeted precision of the measurement, application technique, and optical measurement technique. For example, in some embodiments, the passive strain indicator 40 may comprise a maximum length and width of between 1 millimeter and 300 millimeters. Moreover, the passive strain indicator 40 may comprise any thickness that is suitable for application and subsequent optical identification without significantly impacting the performance of the underlying component 10. For example, in some embodiments, the strain sensor 40 may comprise a maximum thickness of between about 0.01 millimeters and about 1 millimeter. In some embodiments, the passive strain indicator 40 may have a substantially uniform thickness. Such embodiments may help facilitate more accurate measurements for subsequent strain calculations between the various fiducial markers 12.
As discussed, in some embodiments, a passive strain indicator 40 may include a serial region 46 which may include a plurality of serial features 45. These features 45 may generally form any type of barcode, label, tag, serial number, pattern or other identifying system that facilitates the identification of that particular passive strain indicator 40. In some embodiments, the serial region 46 may additionally or alternatively comprise information about the component 10 or the overall assembly that the passive strain indicator 40 is configured on. The serial region 46 may thereby assist in the identification and tracking of particular passive strain indicator 40, components 10 or even overall assemblies to help correlate measurements for past, present and future operational tracking.
The markers 12 may be directly deposited on a portion of the outer surface 14 by various exemplary methods. For instance, in some embodiments, the markers 12 may be printed on the outer surface 14 of the component 10. Suitable printing methods include two-dimensional (2-D) or three-dimensional (3-D) printing, e.g., by screen printing, laser printing, direct ceramic inkjet printing, aerosol jet printing, or another suitable method. In some embodiments, the markers 12 may be directly deposited on the outer surface 14 of the component 10 by additive methods such as laser cladding, electro-spark deposition, spot welding, stick welding, powder-bed printing, soldering, brazing, or any other suitable additive method. In some embodiments, a coating or thin film processing technique may be used to deposit the fiducial markers 12 on the portion of the outer surface. Examples of such techniques which may be used include but are not limited to thermal spray, chemical deposition, physical vapor deposition, atomic layer deposition, and photoresist/chemical etching techniques. One exemplary welding method may include providing a welding rod of the second material and selectively welding the second material onto the outer surface 14 of component 10 to form the fiducial markers 12. In some exemplary embodiments, such as powder-bed printing, the component 10 may also be formed by such additive manufacturing method, and the plurality of fiducial markers 12 may be directly deposited on a portion of the outer surface 14 of the component 10 during formation of the component 10. Other suitable techniques include transferable methods, such as through the use of tapes, stickers, labels, and/or other pre-manufactured transferrable media, with or without integrated adhesive. As additional non-limiting examples, the plurality of fiducial markers 12 may be directly deposited by staining, painting, or adhering.
In additional or alternative embodiments, the fiducial markers 12 may be applied with and/or positioned in an optional bond layer 17 and/or thermal barrier layer 16. In some example embodiments, e.g., as illustrated in
In exemplary embodiments, suitable methods of directly depositing the fiducial markers 12 on the outer surface 14 of the component 10 include methods that do not affect the strength or useful life of the component 10. For example, it may be verified in practice that the grain structure of component 10 has not been adversely affected through microscopic analysis, such as with an electron scanning microscope, of a test piece or sample. Additionally, methods of directly depositing the fiducial markers 12 on the outer surface 14 may be suitable in accordance with the present disclosure when such methods do not create stress risers in the component 10. Suitable methods may also include methods which may create temporary stress risers when the temporary stress riser can be relaxed, e.g., by heat treating.
As a result of such direct deposition, e.g., by printing, welding, or other suitable method, the fiducial markers 12 are integrally joined with the outer surface 14 of the component 10, so as to reduce or minimize movements of the fiducial markers 12 independent or in excess of the component 10. Accordingly, the fiducial markers 12 in accordance with the present disclosure form an integral strain indicator of the component 10. Further, the direct application of fiducial markers 12 on the component 10 may increase durability and reduce the risk that suitable measurement devices will be unable to measure the markers 12 over time.
As noted above, in some embodiments fiducial marker 12 may have a height H (see
The fiducial markers 12 may be positioned in one or more of a variety of locations on various components. For example, as discussed above, the fiducial markers 12 may be positioned on a turbine blade, vane, nozzle, shroud, rotor, transition piece or casing. In such embodiments, the fiducial markers 12 may be configured in one or more locations known to experience various forces during unit operation such as on or proximate airfoils, platforms, tips or any other suitable location. Moreover, the fiducial markers 12 may be deposited in one or more locations known to experience elevated temperatures. For example the fiducial markers 12 may be positioned in a hot gas path and/or on a combustion component 10. In some embodiments, the analysis area may include a life-limiting region of the component, e.g., a high stress or high creep region and/or a region with close tolerances or clearances. For example, in embodiments wherein the component 10 is a turbine blade of a gas turbine engine, there may be a close clearance between the turbine blade and a casing of the turbine at or near an outer portion of the blade. As such the outer portion of the blade may be life-limiting in that deformation of that portion could potentially cause the casing to interfere with rotation of the blade. In other embodiments, the analysis area may include substantially the entire outer surface 14 of component 10. Such embodiments may permit the optional detection of local strain across selective variable sub-portions (e.g., the region between two adjacent markers 12), and/or detection of global strain across the component 10.
It is possible in various embodiments to measure distances between and/or define locations of the fiducial markers based any of several points thereon, for example a point on an edge or outer surface of the fiducial marker, such as an apex, may be used. In some embodiments, the fiducial marker may be or approximate a portion of a sphere, such as a hemisphere, e.g., each fiducial marker of the plurality of fiducial markers may partially define a spherical surface. In such embodiments, a centroid 120 (
A centroid in accordance with the present disclosure is a geometric center of a region, which may be a two-dimensional or three-dimensional region, and is thus the arithmetic mean or average position of all points in the shape. In exemplary embodiments, a centroid may be located through use of the imaging device 24 and processor 26. Processor 26, in analyzing an image of, for example, a fiducial marker, may calculate and thus locate the centroid of the fiducial marker, which may be a physical centroid or a virtual centroid, as discussed above.
Using the centroid of the fiducial markers 12 as the reference point for distance measurement may advantageously reduce or minimize error due to deformation of the markers 12. For example,
Referring now to
In general, as used herein, the term “processor” refers not only to integrated circuits referred to in the art as being included in a computer, but also refers to a controller, a microcontroller, a microcomputer, a programmable logic controller (PLC), an application specific integrated circuit, and other programmable circuits. The processor 26 may also include various input/output channels for receiving inputs from and sending control signals to various other components with which the processor 26 is in communication, such as the three-dimensional data acquisition device 24. The processor 26 may further include suitable hardware and/or software for storing and analyzing inputs and data from the three-dimensional data acquisition device 24, and for generally performing method steps as described herein.
Notably, processor 26 (or components thereof) may be integrated within the three-dimensional data acquisition device 24. In additional or alternative embodiments, the processor 26 (or components thereof) may be separate from the three-dimensional data acquisition device 24. In exemplary embodiments, for example, processor 26 includes components that are integrated within the three-dimensional data acquisition device 24 for initially processing data received by the three-dimensional data acquisition device 24, and components that are separate from the three-dimensional data acquisition device 24 for measuring the fiducial markers 12 and/or assembling contemporary three-dimensional profiles from the data and comparing these profiles.
In general, processor 26 is operable for directly measuring the fiducial markers 12 along an X-axis, a Y-axis and a Z-axis to obtain X-axis data points, Y-axis data points, and Z-axis data points and create accurate 3D digital replications of the topology of surface 14. As discussed, the axes are mutually orthogonal. The X-axis data points, Y-axis data points, and Z-axis data points are dimensional data points related to the direct measurement of the fiducial markers 12. Processor 26 may further be operable for locating a centroid 120 of each fiducial marker 12, e.g., determining three-dimensional coordinates representing the location of the centroid 120. By scanning the component 10 at various times, e.g., before and after deformation events such as creep, fatigue, and overloads, the component 10 may be monitored for, e.g. stress and/or strain. The three-dimensional data acquisition device 24 may be operable to perform a single three-dimensional scan of the component 10 such that a composite scan is not required or performed. The single three-dimensional scan of the component 10 produces three-dimensional data and permits three-dimensional strain analysis. Exemplary embodiments of such three-dimensional data may include polygon mesh data within three-dimensional point clouds, including centroid coordinates in a three-dimensional space defined by the mutually orthogonal axes X, Y, and Z. Such three-dimensional data may then be input to deformation analysis algorithms to calculate regional surface strain.
In general, any suitable three-dimensional data acquisition device 24 which utilizes surface metrology techniques to obtain direct measurements in three dimensions may be utilized. In exemplary embodiments, device 24 is a non-contact device which utilizes non-contact surface metrology techniques. Further, in exemplary embodiments, a device 24 in accordance with the present disclosure has a resolution along the X-axis, the Y-axis and the Z-axis of between approximately 100 nanometers and approximately 100 micrometers. Accordingly, and in accordance with exemplary methods, the X-axis data points, Y-axis data points, and Z-axis data points are obtained at resolutions of between approximately 100 nanometers and approximately 100 micrometers.
For example, in some embodiments, suitable optical scanners 24 which optically identify fiducial markers 12 in three dimensions may be utilized.
Alternatively, other suitable data acquisition devices may be utilized. For example, in some embodiments, device 24 is a laser scanner. Laser scanners generally include lasers which emit light in the form of laser beams towards objects, such as in these embodiments fiducial markers 12 and turbine components 10 generally. The light is then detected by a sensor of the device 24. For example, in some embodiments, the light is then reflected off of surfaces which it contacts, and received by a sensor of the device 24. The round-trip time for the light to reach the sensor is utilized to determine measurements along the various axes. These devices are typically known as time-of-flight devices. In other embodiments, the sensor detects the light on the surface which it contacts, and determines measurements based on the relative location of the light in the field-of-view of the sensor. These devices are typically known as triangulation devices. X-axis, Y-axis and Z-axis data points are then calculated based on the detected light, as mentioned. Notably, in exemplary embodiments processor 26 performs and operates such data acquisition devices 24 to perform various above disclosed steps.
In some embodiments, the light emitted by a laser is emitted in a band which is only wide enough to reflect off a portion of object to be measured, such as the plurality of fiducial markers 12. In these embodiments, a stepper motor or other suitable mechanism for moving the laser may be utilized to move the laser and the emitted band as required until light has been reflected off of the entire object to be measured.
Still further, other suitable three-dimensional data acquisition devices 24 may be utilized. Alternatively, however, the present disclosure is not limited to the use of three-dimensional data acquisition devices 24. For example, other suitable devices include electrical field scanners, which may include for example an eddy current coil, a Hall Effect probe, a conductivity probe, and/or a capacitance probe.
Referring now to
Referring now to
In some embodiments, the three-dimensional model of the component 10 based on the initial measurement may also include a representation of an initial location of each fiducial marker 12, e.g., three-dimensional coordinates representing the location of centroid 120 in a three-dimensional space defined by axes X, Y, and Z, as described above. Some embodiments of the three-dimensional model of the component based on the subsequent measurement may also include a representation of a subsequent location of each fiducial marker, which may be three-dimensional centroid coordinates similar to the representation of the initial location of each fiducial marker. Further, in such embodiments of method 300 the step 370 of comparing may include comparing the initial locations of the plurality of fiducial markers to the subsequent locations of the plurality of fiducial markers.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
