Patent Publication Number: US-10768147-B2

Title: Probe approach for DGS sizing

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 15/488,702, entitled “PROBE APPROACH FOR DGS SIZING,” filed Apr. 17, 2017, which is continuation of U.S. patent application Ser. No. 15/097,348 (now U.S. Pat. No. 9,661,651), entitled “PROBE APPROACH FOR DGS SIZING,” filed Apr. 13, 2016, which is continuation of U.S. patent application Ser. No. 13/706,531 (now U.S. Pat. No. 9,335,302), entitled “PROBE APPROACH FOR DGS SIZING,” filed Dec. 6, 2012, each of which is hereby incorporated herein by reference in its entirety. 
    
    
     FIELD 
     The disclosed subject matter relates generally to ultrasonic detection assemblies, and more particularly, to ultrasonic detection assemblies including phased array probes. 
     BACKGROUND 
     Ultrasonic detection assemblies are known and used in many different applications. Ultrasonic detection assemblies are used, for example, to inspect a test object and to detect/identify characteristics of the test object, such as corrosion, voids, inclusions, length, thickness, etc. To accurately detect the location of these characteristics within the test object, a straight beam probe was previously used. The straight beam probe emitted a generally straight sound beam into the test object. A wedge was used to provide for inclined sound beams from the straight beam probe into the test object. Multiple different angles (e.g., 3.5°, 7°, 10.5°, 14°, 17.5°, 21°, 24°, etc.) were required to be tested since not all characteristics could be detected with the straight beam probe. 
     Following these tests, a DGS (distance, gain, size) method was used to determine a size of the characteristic in the test object based on comparing an amplitude of the sound beams for the various angles. The DGS method generally uses straight beam probes generating a rotationally symmetric sound field in the test object. Providing multiple test runs is time consuming, leading to decreased productivity. Further, using differently sized wedges for each of the specified angles (or using multiple probes simultaneously) is difficult, expensive, and time consuming. 
     SUMMARY 
     The following presents a simplified summary of the disclosed subject matter in order to provide a basic understanding of some example aspects of the disclosed subject matter. This summary is not an extensive overview of the disclosed subject matter. Moreover, this summary is not intended to identify critical elements of the disclosed subject matter nor delineate the scope of the disclosed subject matter. The sole purpose of the summary is to present some concepts of the disclosed subject matter in simplified form as a prelude to the more detailed description that is presented later. 
     In accordance with one aspect, an ultrasonic detection assembly for detecting a characteristic in a test object having a cylindrical peripheral surface is provided. The ultrasonic detection assembly includes a phased array probe positioned in proximity to the cylindrical peripheral surface of the test object. The phased array probe includes a plurality of adjacent transducer elements. Each transducer is operatively configured to emit a respective beam into the test object so as to provide a pattern of constructive interference. The ultrasonic detection assembly includes means for providing cylindrical contact between the phased array probe and the cylindrical peripheral surface of the test object. The ultrasonic detection assembly includes a controller operatively connected to the phased array probe for causing each transducer to emit the respective beam into the test object. 
     In accordance with another aspect, an ultrasonic detection assembly for detecting a characteristic in a test object having a cylindrical peripheral surface is provided. The ultrasonic detection assembly includes a phased array probe positioned in proximity to the cylindrical peripheral surface of the test object. The phased array probe includes a plurality of adjacent transducer elements. Each transducer is operatively configured to emit a respective beam into the test object so as to provide a pattern of constructive interference. The ultrasonic detection assembly includes a controller operatively connected to the phased array probe for causing each transducer to emit the respective beam into the test object. The ultrasonic detection assembly is structurally configured to provide for cylindrical contact between the phased array probe and the cylindrical peripheral surface of the test object. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other aspects of the disclosed subject matter will become apparent to those skilled in the art to which the disclosed subject matter relates upon reading the following description with reference to the accompanying drawings, in which: 
         FIG. 1  is a schematic, perspective view of an example ultrasonic detection assembly including a phased array probe detecting a characteristic of a test object in accordance with an aspect of the disclosed subject matter; 
         FIG. 2  is a side elevation view of the example ultrasonic sensor assembly that is partially torn open to show an interior portion of the test object; 
         FIG. 3  is an end view of an inspection surface of the phased array probe; 
         FIG. 4  is an end view of a second example inspection surface of the phased array probe; 
         FIG. 5  is a side elevation view of the example ultrasonic sensor assembly similar to  FIG. 2  as the phased array probe transmits a rotationally symmetric sound beam into the test object; and 
         FIG. 6  is a sectional view of a second example ultrasonic sensor assembly along line  6 - 6  of  FIG. 2  including an adjustment structure for positioning the phased array probe in proximity to the test object. 
     
    
    
     DETAILED DESCRIPTION 
     Example embodiments that incorporate one or more aspects of the disclosed subject matter are described and illustrated in the drawings. These illustrated examples are not intended to be a limitation on the disclosed subject matter. For example, one or more aspects of the disclosed subject matter can be utilized in other embodiments and even other types of devices. Moreover, certain terminology is used herein for convenience only and is not to be taken as a limitation on the disclosed subject matter. Still further, in the drawings, the same reference numerals are employed for designating the same elements. 
       FIG. 1  illustrates a perspective view of an example ultrasonic detection assembly  10  according to one aspect of the disclosed subject matter. The ultrasonic detection assembly  10  is for inspection of an example test object  12  having a characteristic  18  (e.g., void, inclusion, thickness, crack, corrosion, etc.). The ultrasonic detection assembly  10  includes a phased array probe  20  positioned in proximity to a peripheral surface  14  of the test object  12 . The phased array probe  20  can detect the characteristic  18  by directing one or more rotationally symmetric (e.g., generally circular) sound beams into the test object  12 . To provide improved detection within the test object  12 , the phased array probe  20  can move (e.g., steer) the rotationally symmetric sound beams along a variety of directions within the test object  12 . 
     The example test object  12  includes a tubular shaft having a generally cylindrical shape in  FIG. 1 . The test object  12  extends between opposing ends and can include a solid body (as shown) or a non-solid body (e.g., hollow body, pipe, or the like). It is to be appreciated that the test object  12  is somewhat generically/schematically depicted in  FIG. 1  for ease of illustration. Indeed, the test object  12  can include a variety of dimensions, such as by being longer or shorter than as shown, or by having a larger or smaller diameter. Further, the test object  12  is not limited to a pipe-like structure extending along a linear axis, and may include bends, undulations, curves, or the like. 
     The peripheral surface  14  of the test object  12  provides the generally cylindrical shape. In other examples, the test object  12  includes other non-cylindrical shapes and sizes. For example, the test object  12  could have a non-circular cross-sectional shape, such as by having a square or rectangular cross-section. Still further, the test object  12  may include a tubular shape, conical shape, or the like. The test object  12  is not limited to shafts, pipes, or the like, but instead, could include walls, planar or non-planar surfaces, etc. The test object  12  could be used in a number of applications, including inspection of parts (e.g., generator shafts, etc.), pipeline corrosion monitoring, or the like. As such, the test object  12  shown in  FIG. 1  includes only one possible example of the test object. 
     The ultrasonic detection assembly  10  further includes a controller  15 . The controller  15  is somewhat generically/schematically depicted. In general, the controller  15  can include any number of different configurations. In one example, the controller  15  is operatively attached to the phased array probe  20  by means of a wire. In further examples, however, the controller  15  could be in wireless communication with the phased array probe  20 . The controller  15  can send and receive information (e.g., data, control instructions, etc.) from the phased array probe  20  through the wire (or wirelessly). This information can be related to characteristics of the test object  12  (e.g., corrosion, wall thickness, voids, inclusions, etc.), characteristics of sound beams transmitted and/or received by the phased array probe  20 , or the like. The controller  15  can include circuits, processors, running programs, memories, computers, power supplies, ultrasound contents, or the like. In further examples, the controller  15  includes a user interface, display, and/or other devices for allowing a user to control the ultrasonic detection assembly  10 . 
     Turning now to  FIG. 2 , a partially torn open side elevation view of the test object  12  is shown. The test object  12  includes an interior portion  16 . The interior portion  16  is substantially solid, though in further examples, the interior portion  16  could be at least partially hollow and/or include openings therein. The interior portion  16  of the test object  12  could be formed of a number of different materials, including metals (e.g., steel, titanium, etc.), metal alloys, and/or non-metals (e.g., concrete, or the like). It is to be appreciated that while only a portion of the interior portion  16  of the test object  12  is shown (i.e., the torn open portion), the remaining interior portions of the test object  12  can be similar or identical in structure as the interior portion  16  shown in  FIG. 2 . 
     The test object  12  can further include a characteristic  18 . The characteristic  18  is somewhat generically/schematically depicted, as it is to be appreciated that the characteristic  18  includes a number of possible structures, sizes, shapes, etc. For example, the characteristic  18  includes corrosion, voids, inclusions, defects, cracks, thicknesses, etc. Further, while the characteristic  18  is generically depicted as a quadrilateral shape, the characteristic  18  could likewise include elongated cracks/defects, non-quadrilateral shapes, or the like. It is further appreciated that  FIG. 2  depicts one characteristic for illustrative purposes, but in further examples, the characteristic  18  could likewise include a plurality of characteristics. The characteristic  18  may be positioned at any location within the interior portion  16 , such as by being closer to or farther from the phased array probe  20 , closer to one of the ends of the test object  12 , etc. 
     Turning to the phased array probe  20  of the ultrasonic detection assembly  10 , the phased array probe  20  is an elongate, cylindrically shaped probe extending between opposing ends. In further examples, the phased array probe  20  is not limited to the specific structure shown in  FIG. 2 , and could include any number of different sizes and shapes. The phased array probe  20  is positioned in proximity to the peripheral surface  14  of the test object  12 . In one example, the phased array probe  20  is non-movably positioned in proximity to the test object  12 , such that the phased array probe  20  is statically held, attached, etc. with respect to the test object  12 . 
     The phased array probe  20  includes an inspection surface  22  disposed at an end of the phased array probe  20 . The inspection surface  22  can be substantially planar (as shown), or in further examples, could include bends, curves, or the like to match the shape of the peripheral surface  14 . In one example, when the test object  12  has a relatively larger diameter than a length across the inspection surface  22 , the inspection surface  22  can be substantially planar such that the inspection surface  22  is in contact with the peripheral surface  14 . By being positioned in proximity to the peripheral surface  14 , the inspection surface  22  is positioned in contact with the peripheral surface  14 . In another example, the inspection surface  22  may be positioned in proximity to the peripheral surface  14  but may not be in contact with the peripheral surface  14 . In such an example, the inspection surface  22  may be spaced apart a distance from the peripheral surface  14  and/or may include other structures positioned between (and in contact with) the inspection surface  22  on one side and the peripheral surface  14  on an opposite side. 
     Turning now to  FIG. 3 , an example of the inspection surface  22  of the phased array probe  20  is shown. The inspection surface  22  includes a generally circular shape associated with a plurality of transducer elements  24 . As is generally known, each of the transducer elements  24  includes a piezoelectric crystal. In response to an application of electric current to the transducer elements  24 , each of the transducer elements  24  can transmit (e.g., send, convey, etc.) a sound beam in a direction outwardly from the inspection surface  22 . Likewise, each of the transducer elements  24  can receive a sound beam, which produces an electrical current in response. 
     The transducer elements  24  associated with the inspection surface  22  are laterally spaced apart, such as by being linearly segmented. In particular, the transducer elements  24  can be separated by segments  26  that extend generally linearly across the inspection surface  22 . The segments  26  extend parallel to each other, such that the transducer elements  24  are arranged to form a linear array. The segments  26  can represent any type of segmentation/separation between the transducer elements  24 . For example, the segments  26  can represent cuts, scores, or similar separations manufactured into the inspection surface  22 . In another example, the segments  26  represent a space between separately provided transducer elements  24 . The segments  26  can be closer together or farther apart, such that the transducer elements  24  could be narrower or wider, respectively. 
     By providing the transducer elements  24  as being linearly segmented, a sound beam transmitted from the inspection surface  22  can be guided/moved. For example, each of the transducer elements  24  will emit a separate sound beam. The transmission of sound beams from adjacent transducer elements can be delayed (e.g., time shifted), such that a pattern of constructive interference is formed which results in a single sound beam being transmitted at a certain angle. Based on this delay and time shifting, the sound beam from the transducer elements  24  can effectively be moved/guided from the inspection surface  22  and into the test object  12 . In the shown example, the sound beam can be moved along a two dimensional direction  27  (represented generically as an arrowhead). 
     Turning now to  FIG. 4 , a second example of an inspection surface  122  of the phased array probe  20  is shown. In this example, the second inspection surface  122  includes a generally square shape, though other shapes are envisioned. The second inspection surface  122  is associated with a plurality of second transducer elements  124 . As is generally known, each of the second transducer elements  124  includes a piezoelectric crystal. As set forth above, each of the second transducer elements  124  can transmit (e.g., send, convey, generate, etc.) a sound beam in a direction outwardly from the second inspection surface  122 . Likewise, each of the second transducer elements  124  can receive a sound beam, which produces an electrical current in response. 
     The second transducer elements  124  associated with the second inspection surface  122  are arranged as a matrix. In particular, the second inspection surface  122  includes a rectangular array of second transducer elements  124  arranged into rows and columns. In the shown example, the matrix includes an 8×8 matrix, with eight rows of second transducer elements  124  and eight columns of second transducer elements  124 . Of course, in further examples, the second inspection surface  122  is not limited to including the 8×8 matrix, and could include a matrix of nearly any size (i.e., larger or smaller than as shown). Likewise, the second inspection surface  122  is not limited to including the rectangular array, and could include other quadrilateral shaped arrays, or even non-quadrilateral shaped arrays. 
     The second transducer elements  124  are separated by segments  126 . The segments  126  can extend generally linearly from one side to an opposing second side of the second inspection surface  122 . Further, the segments  126  can have a generally consistent spacing between adjacent segments, such that the second transducer elements  124  have substantially identical sizes and shapes (e.g., square shapes). Of course, in further examples, the segments  126  could be oriented in any number of ways. For example, the segments  126  could be angled diagonally across the second inspection surface  122 , such that the second transducer elements  124  include non-square shapes. 
     By providing the second transducer elements  124  in the form of a matrix, a sound beam transmitted from the second inspection surface  122  can be rotationally symmetric. For example, a portion of the second transducer elements  124  (i.e., less than all) can be activated to emit a separate sound beam. In the shown example, active elements  124   a  will emit sound beams while inactive elements  124   b  may not emit sound beams. The active elements  124   a  can form a generally circular shape, indicated as a generally circular grouping  130 . The circular grouping  130  of the active elements  124   a  can be disposed towards the center of the second inspection surface  122 . The inactive elements  124   b  are disposed generally towards the corners of the second inspection surface  122 . In the shown example, the active elements  124   a  can include four transducer elements at a center of each side of the second inspection surface  122 . However, in further examples, the circular grouping  130  could be smaller, such that fewer active elements  124   a  will emit sound beams. 
     The active elements  124   a  forming the circular grouping  130  will emit separate sound beams. Similar to the example shown in  FIG. 3 , the transmission of the sound beams from the active elements  124   a  can be delayed (e.g., time shifted), such that a pattern of constructive interference is formed which results in a single sound beam being transmitted at a certain angle. Based on this delay and time shifting, the sound beam from the active elements  124   a  can effectively be moved/guided from the second inspection surface  122  and into the test object  12 . In this example, the rotationally symmetric sound beam generated and transmitted by the active elements  124   a  is moved along a three dimensional direction  127  (represented generically as an arrowhead). As such, the rotationally symmetric sound beam can be moved three dimensionally within the test object  12 . 
     It is to be appreciated that the arrowhead representing the three dimensional direction  127  includes only two perpendicular lines (e.g., first line pointing up/down and second line pointing side to side). However, the movement of the sound beam is not so limited to moving along these directions (e.g., up, down, left, right). Rather, the three dimensional movement of the sound beam includes directions other than those represented with the arrowhead, such as by moving in an angled direction with respect to the perpendicular lines. Indeed, the arrowhead representing the three dimensional direction  127  is merely intended to show that the sound beam emanating from the second inspection surface  122  is not limited to the two dimensional direction  27  of  FIG. 3 . 
     Turning now to  FIG. 5 , the operation of detecting the characteristic in the test object  12  with the ultrasonic detection assembly  10  will now be described. As shown, the phased array probe  20  is positioned in proximity to the test object  12 . In particular, the inspection surface  22  (or the second inspection surface  122 ) of the phased array probe  20  is in contact with the peripheral surface  14  of the test object  12 . The test object  12  includes the characteristic  18  positioned within the interior portion  16 . 
     Initially, the phased array probe  20  will generate and transmit a sound beam  50  into the test object  12 . The sound beam  50  can include the rotationally symmetric sound beam described above with respect to  FIG. 3 or 4 . In particular, the phased array probe  20  in  FIG. 5  can include either of the inspection surface  22  ( FIG. 3 ) or the second inspection surface ( FIG. 4 ). 
     The sound beam  50  can initially be in a first sound beam position  50   a . The first sound beam position  50   a  can extend at an angle with respect to the inspection surface  22  into the interior portion  16 . It is to be appreciated that the first sound beam position  50   a  is not specifically limited to the location shown in  FIG. 5 , and could be located at any position within the interior portion  16 . Next, the phased array probe  20  can move the sound beam  50 . For example, the transmission of the sound beam  50  from the transducer elements  24  can be delayed (e.g., time shifted), to form a pattern of constructive interference. Based on this delay and time shifting, the sound beam  50  from the inspection surface  22  can be moved/guided within the interior portion  16 . In particular, the sound beam  50  can be moved along a direction  52 , such that the sound beam  50  will move from the first sound beam position  50   a  to a second sound beam position  50   b.    
     As the sound beam  50  moves within the test object  12 , the sound beam  50  can detect the characteristic  18  within the interior portion  16 . In particular, an echo of the sound beam  50  can reflect off the characteristic  18 , whereupon the echo is received by the transducer elements  24 . Information related to this echo (e.g., amplitude, time of flight, etc.) can be compared with echo signals of known circular disk reflectors. Using a DGS diagram, information related to the characteristic  18  is determinable by comparing the echo amplitude with an array of curves of circular disk reflectors recorded in the DGS diagram. In particular, since the sound beam  50  from either the inspection surface  22  or second inspection surface  122  is rotationally symmetric, the DGS method can still be used since the DGS method depends on a rotationally symmetric sound field. 
     It is to be appreciated that the first sound beam position  50   a  and second sound beam position  50   b  are somewhat generically/schematically represented. Indeed, in further examples, the range along which the sound beam  50  moves is not limited to the range shown in  FIG. 5 . In one particular example, the sound beam  50  can have a range of approximately 48°, from +24° to −24° with respect to a perpendicular axis extending through a center of the inspection surface  22 . Of course, in other examples, the sound beam  50  could have a larger or smaller range. The range of the sound beam  50  can depend on the size of the transducer elements, such that smaller sized transducer elements allow for a larger range. 
     The sound beam  50  in  FIG. 5  is shown to move along the direction  52  that is generally parallel to the axial direction of the test object  12 . However, in further examples, rotation of the phased array probe  20  will cause the sound beam  50  to move in other directions that are not parallel to the axial direction of the test object  12 . For example, the phased array probe  20  could be rotated 90°, such that the direction  52  of the sound beam  50  is substantially transverse to the axial direction of the test object  12 . In other examples, the phased array probe  20  includes the second inspection surface  122 . As such, the sound beam  50  is movable along three dimensions. 
     Turning now to  FIG. 6 , a second example of an ultrasonic detection assembly  110  is shown.  FIG. 6  depicts a sectional view along line  6 - 6  of  FIG. 2 . In this example, however, the second ultrasonic detection assembly  110  includes an adjustment structure  112 . The test object  12  is generally identical to the test object  12  described above with respect to  FIGS. 1 to 5 . Likewise, the phased array probe  20  is also generally identical to the phased array probe  20  described above with respect to  FIGS. 1 to 5 . As such, the test object  12  and phased array probe  20  will not be described again with respect to  FIG. 6 . 
     The second ultrasonic detection assembly  110  shown in  FIG. 6  is a sectional view of  FIG. 2 . However, the second ultrasonic detection assembly  110  includes the adjustment structure  112  while  FIG. 2  does not show the adjustment structure  112 . It is to be appreciated that  FIG. 6  is similar to  FIG. 2 , but also includes the adjustment structure  112 . In particular, for ease of illustration and to more clearly show portions of the disclosed subject matter, a sectional view of the second ultrasonic detection assembly  110  is shown to include the adjustment structure  112 . In operation, the second ultrasonic detection assembly  110  will include the adjustment structure  112  when shown in perspective view. 
     The second ultrasonic detection assembly  110  includes the adjustment structure  112 . The adjustment structure  112  functions to improve contact between the phased array probe  20  and the test object  12 . For example, the adjustment structure  112  includes a first surface  113  and a second surface  114 . The first surface  113  includes a size and shape that substantially matches a size and shape of the inspection surface  22 . For example, the first surface  113  has a generally planar shape that matches the planar shape of the inspection surface  22 . In further examples, the first surface  113  could include other, non-planar shapes, that match a non-planar shape of the inspection surface. Indeed, the inspection surface could include either of the inspection surface  22  shown in  FIG. 3  or the second inspection surface  122  shown in  FIG. 4 , with the first surface  113  engaging and contacting either of the inspection surface  22  or second inspection surface  122 . 
     The adjustment structure  112  further includes the second surface  114 . The second surface  114  has a size and shape that substantially matches a size and shape of the peripheral surface  14  of the test object  12 . For example, the second surface  114  includes a curved, generally concave surface that receives and contacts the peripheral surface  14  of the test object  12 . Of course, the second surface  114  is not so limited to the shape shown in  FIG. 6 . Instead, in further examples, the test object  12  could have a larger or smaller diameter than as shown. To accommodate for this larger or smaller diameter, the second surface  114  could have a greater or lesser degree of concavity, such that the second surface  114  will receive the test object  12 . 
     The adjustment structure  112  could include any number of materials. In one example, the adjustment structure  112  includes an acrylic material, such as polymethyl methacrylate (e.g., Plexiglass®) or the like. The adjustment structure  112  can be clear or opaque, such that a sound beam  150  can pass through the adjustment structure  112 . 
     The phased array probe  20  will transmit the sound beam  150  from the inspection surface  22  and into the test object  12 . The sound beam  150  can pass through the adjustment structure  112 , by entering through the first surface  113  and then exiting through the second surface  114 . The adjustment structure  112  can have a certain influence on the sound beam  150  due to refraction. In particular, as shown in  FIG. 6 , the sound beam  150  can change directions by passing through the adjustment structure  112 . The influence on the sound beam  150  by the adjustment structure  112  could be larger or smaller than as shown, such that the refraction of the sound beam  150  could be more or less severe in further examples. Accordingly, this refraction of the sound beam  150  can be compensated for by knowing the characteristics of the adjustment structure  112 , including dimensions (thickness, concavity, etc.), type of material, etc. As such, the sound beam  150  can be moved in a similar manner as described above with respect to  FIG. 5  while compensating for refraction due to the adjustment structure  112 . 
     Providing the adjustment structure  112  allows for enhanced coupling of the phased array probe  20  and the test object  12 . In examples in which the test object  12  has a relatively small diameter as compared to a size of the inspection surface  22 , the adjustment structure  112  is provided to reduce gaps, spaces, etc. between the inspection surface  22  and the test object  12 . Without the adjustment structure  112 , these gaps, spaces, etc. may exist at edges of the inspection surface  22 . The sound beam may be distorted or less effective by traveling from the inspection surface  22 , through the gap, space, etc., and then into the test object  12 . By including the adjustment structure  112 , the sound beam  150  may no longer need to travel through such gaps, and instead can pass through the adjustment structure  112  at positions where the inspection surface  22  and peripheral surface  14  are not in contact (or not adjacent each other). 
     One example ultrasonic detection assembly includes a phased array probe positioned in proximity to a peripheral surface of the test object, the phased array probe including a plurality of adjacent transducer elements collectively configured to provide an inspection surface extending substantially parallel to a direction along which the test object extends, each transducer being operatively configured to emit a respective beam into the test object so as to provide a pattern of constructive interference such that the phased array probe is providing a single, rotationally symmetric sound beam into the test object, the phased array probe being configured to provide for a rotational symmetry that exists over a complete steering range of the phased array probe. 
     Another example ultrasonic detection assembly includes a phased array probe positioned in proximity to a peripheral surface of the test object, the phased array probe including a plurality of adjacent transducer elements collectively configured to provide an inspection surface, each transducer being operatively configured to emit a respective beam into the test object so as to provide a pattern of constructive interference such that the phased array probe is providing a single, rotationally symmetric sound beam into the test object, the phased array probe being configured to move the sound beam within a range of angles from the phased array probe and bounded by a first beam position extending in a first direction from the phased array probe and a second beam position extending in a second, different direction from the phased array probe within the test object to detect the characteristic. 
     Another example ultrasonic detection assembly includes a phased array probe positioned in proximity to a peripheral surface of the test object, the phased array probe being configured to transmit a sound beam into the test object, wherein the sound beam is movable by the phased array probe within the test object to detect the characteristic. The phased array probe includes a plurality of transducer elements that are configured to transmit the sound beam, an inspection surface of the transducer elements configured to extend substantially parallel to a direction along which the test object extends. 
     The disclosed subject matter has been described with reference to the example embodiments described above. Modifications and alterations will occur to others upon a reading and understanding of this specification. Example embodiments incorporating one or more aspects of the disclosed subject matter are intended to include all such modifications and alterations insofar as they come within the scope of the appended claims.