Patent Publication Number: US-2022221707-A1

Title: Insertion tool

Description:
FIELD 
     The present subject matter relates generally to a tool for inspecting an environment and/or performing maintenance operations on a component within the environment, such as within an annular space in a turbine engine. 
     BACKGROUND 
     At least certain gas turbine engines include, in serial flow arrangement, a compressor section including a low pressure compressor and a high-pressure compressor for compressing air flowing through the engine, a combustor for mixing fuel with the compressed air such that the mixture may be ignited, and a turbine section including a high pressure turbine and a low pressure turbine for providing power to the compressor section. 
     Within one or more of the sections, at least certain gas turbine engines define an annular opening. Certain of these annular openings may vary in size, such that a dedicated, specialized insertion tool must be utilized with each annular opening to extend around and through such annular opening. 
     The inventors of the present disclosure have come up with an insertion tool that may be inserted into an annular opening. The insertion tool that the inventors have come up with may benefit from the inclusion of relatively complex geometries and features. Accordingly, an insertion tool formed in a manner that meets these needs would be useful. 
     BRIEF DESCRIPTION 
     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 one exemplary embodiment of the present disclosure, an insertion tool for performing an operation on equipment, the insertion tool comprising: a plurality of segments, each segment of the plurality of segments including a body comprising: a first hinge member; and a second hinge member, the first hinge member of a first segment being coupled to the second hinge member of a second segment adjacent to the first segment through an interface, wherein the interface comprises a powder gap, a multi-modal interface, a compliance feature, a displace-to-lock configuration, an interference fit, or any combination thereof. 
     According to another exemplary embodiment, an insertion tool for performing an operation on equipment, the insertion tool comprising: a plurality of segments, each segment of the plurality of segments including a body comprising: a first hinge member; and a second hinge member, the first hinge member of a first segment being coupled to the second hinge member of a second segment adjacent to the first segment through an interface, wherein the interface comprises a powder gap, a multi-modal interface, a compliance feature, a displace-to-lock configuration, an interference fit, or any combination thereof; and a strength member intersecting the interface. 
     According to another exemplary embodiment, a method of forming an insertion tool, the method comprising: additively forming bodies of segments of the insertion tool; and flexing adjacent segments of the insertion tool relative to one another such that powder contained at an interface between adjacent segments of the insertion tool can pass from the interface through a powder gap. 
     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. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       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. 
         FIG. 1  is a cross-sectional schematic view of a high-bypass turbofan jet engine in accordance with an exemplary embodiment of the present disclosure. 
         FIG. 2  is a close-up, cross-sectional view of a combustion section of the exemplary gas turbine engine of  FIG. 1  including an insertion tool in accordance with an exemplary embodiment of the present disclosure, along an axial direction and a radial direction. 
         FIG. 3  is another close-up, cross-sectional view of the combustion section of the exemplary gas turbine engine of  FIG. 1  including the exemplary insertion tool, along the radial direction and a circumferential direction. 
         FIG. 4  is a perspective view of an insertion tool in accordance with an exemplary embodiment of the present disclosure. 
         FIG. 5  is a perspective view of an insertion tool in accordance with an exemplary embodiment of the present disclosure. 
         FIG. 6  is an enlarged view of an end of a segment of an insertion tool in accordance with an exemplary embodiment of the present disclosure. 
         FIG. 7  is an enlarged view of another end of a segment of an insertion tool in accordance with an exemplary embodiment of the present disclosure. 
         FIG. 8  is a perspective view of an insertion tool in accordance with an exemplary embodiment of the present disclosure. 
         FIG. 9  is an enlarged view of a distal end of an insertion tool in accordance with an exemplary embodiment of the present disclosure. 
         FIG. 10  is a perspective view of an interface between adjacent segments of an insertion tool in accordance with an exemplary embodiment of the present disclosure as seen in a non-rigidized configuration. 
         FIG. 11  is a perspective view of an interface between adjacent segments of an insertion tool in accordance with an exemplary embodiment of the present disclosure as seen in a non-rigidized configuration. 
         FIG. 12  is a perspective view of an interface between adjacent segments of an insertion tool in accordance with an exemplary embodiment of the present disclosure as seen in a rigidized configuration. 
         FIG. 13A  is a side view of an interface between adjacent segments of an insertion tool in accordance with an exemplary embodiment of the present disclosure as seen in a rigidized configuration. 
         FIG. 13B  is an enlarged schematic view of an interface between adjacent segments of an insertion tool in accordance with an exemplary embodiment of the present disclosure as seen in a rigidized configuration. 
         FIG. 14A  is a side view of an interface between adjacent segments of an insertion tool in accordance with an exemplary embodiment of the present disclosure as seen in a rigidized configuration. 
         FIG. 14B  is a side view of an interface between adjacent segments of an insertion tool in accordance with an exemplary embodiment of the present disclosure as seen in a non-rigidized configuration. 
         FIG. 15A  is a side view of an interface between adjacent segments of an insertion tool in accordance with an exemplary embodiment of the present disclosure as seen in a rigidized configuration. 
         FIG. 15B  is a side view of an interface between adjacent segments of an insertion tool in accordance with an exemplary embodiment of the present disclosure as seen in a disconnected configuration. 
         FIG. 16A  is a side view of an interface between adjacent segments of an insertion tool in accordance with an exemplary embodiment of the present disclosure as seen in a rigidized configuration. 
         FIG. 16B  is a side view of an interface between adjacent segments of an insertion tool in accordance with an exemplary embodiment of the present disclosure as seen in a disconnected configuration. 
         FIG. 16C  is a cross-sectional view of the interface between adjacent segments as seen along Line C-C in  FIG. 16A  in accordance with an embodiment. 
     
    
    
     Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention. 
     DETAILED DESCRIPTION 
     Reference now will be made in detail to present embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the invention. 
     The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other implementations. Moreover, 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 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. 
     As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. The terms “coupled,” “fixed,” “attached to,” and the like refer to both direct coupling, fixing, or attaching, as well as indirect coupling, fixing, or attaching through one or more intermediate components or features, unless otherwise specified herein. 
     The terms “forward” and “aft” refer to relative positions within a gas turbine engine or vehicle, and refer to the normal operational attitude of the gas turbine engine or vehicle. For example, with regard to a gas turbine engine, forward refers to a position closer to an engine inlet and aft refers to a position closer to an engine nozzle or exhaust. The terms “upstream” and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows. 
     Approximating language, as used herein throughout the specification and claims, is applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about,” “approximately,” and “substantially,” are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value, or the precision of the methods or machines for constructing or manufacturing the components and/or systems. For example, the approximating language may refer to being within a 10 percent margin. 
     Here and throughout the specification and claims, range limitations are combined and interchanged, such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise. For example, all ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other. 
     In general, an insertion tool in accordance with one or more embodiments described herein can be configured to permit an operator or robotic assembly to service (e.g., inspect and/or repair) a cavity, such as an internal volume of a gas turbine engine. The insertion tool can generally include a plurality of adjacent segments which are selectively rigidizable with respect to one another so as to permit a distal end of the insertion tool access to a confined cavity of the equipment through a complex pathway. Adjacent segments can define hinge members which together form an interface between the adjacent segments. The hinge members can include features to enhance operation of the insertion tool during use, such as when inserting the insertion tool into the internal volume of the gas turbine engine. 
     Referring now to the drawings, wherein identical numerals indicate the same elements throughout the figures,  FIG. 1  is a schematic cross-sectional view of a gas turbine engine in accordance with an exemplary embodiment of the present disclosure. More particularly, for the embodiment of  FIG. 1 , the gas turbine engine is a high-bypass turbofan jet engine  10 , referred to herein as “turbofan engine  10 .” As shown in  FIG. 1 , the turbofan engine  10  defines an axial direction A (extending parallel to a longitudinal centerline  12  provided for reference) and a radial direction R. The turbofan engine  10  also defines a circumferential direction C (see  FIG. 3 ) extending circumferentially about the axial direction A. In general, the turbofan  10  includes a fan section  14  and a turbomachine  16  disposed downstream from the fan section  14 . 
     The exemplary turbomachine  16  depicted is generally enclosed within a substantially tubular outer casing  18  that defines an annular inlet  20  and an annular exhaust  21 . The outer casing  18  encases, in serial flow relationship, a compressor section including a booster or low pressure (LP) compressor  22  and a high pressure (HP) compressor  24 ; a combustion section  26 ; a turbine section including a high pressure (HP) turbine  28  and a low pressure (LP) turbine  30 ; and a jet exhaust nozzle section  32 . A high pressure (HP) shaft or spool  34  drivingly connects the HP turbine  28  to the HP compressor  24 . A low pressure (LP) shaft or spool  36  drivingly connects the LP turbine  30  to the LP compressor  22 . The compressor section, combustion section  26 , turbine section, and nozzle section  32  together define a core air flowpath  37  therethrough. 
     For the embodiment depicted, the fan section  14  includes a fixed pitch fan  38  having a plurality of fan blades  40 . The fan blades  40  are each attached to a disk  42 , with the fan blades  40  and disk  42  together rotatable about the longitudinal axis  12  by the LP shaft  36 . For the embodiment depicted, the turbofan engine  10  is a direct drive turbofan engine, such that the LP shaft  36  drives the fan  38  of the fan section  14  directly, without use of a reduction gearbox. However, in other exemplary embodiments of the present disclosure, the fan  38  may instead be a variable pitch fan, and the turbofan engine  10  may include a reduction gearbox, in which case the LP shaft  36  may drive the fan  38  of the fan section  14  across the gearbox. 
     Referring still to the exemplary embodiment of  FIG. 1 , the disk  42  is covered by rotatable front hub  48  aerodynamically contoured to promote an airflow through the plurality of fan blades  40 . Additionally, the exemplary turbofan engine  10  includes an annular nacelle assembly  50  that circumferentially surrounds the fan  38  and/or at least a portion of the turbomachine  16 . For the embodiment depicted, the nacelle assembly  50  is supported relative to the turbomachine  16  by a plurality of circumferentially-spaced outlet guide vanes  52 . Moreover, a downstream section  54  of the nacelle assembly  50  extends over an outer portion of the casing  18  so as to define a bypass airflow passage  56  therebetween. The ratio between a first portion of air through the bypass airflow passage  56  and a second portion of air through the inlet  20  of the turbomachine  16 , and through the core air flowpath  37 , is commonly known as a bypass ratio. 
     It will be appreciated that although not depicted in  FIG. 1 , the turbofan engine  10  may further define a plurality of openings allowing for inspection of various components within the turbomachine  16 . For example, the turbofan engine  10  may define a plurality of borescope openings at various axial positions within the compressor section, combustion section  26 , and turbine section. Additionally, as will be discussed below, the turbofan engine  10  may include one or more igniter ports within, e.g., the combustion section  26  of the turbomachine  16 , that may allow for inspection of the combustion section  26 . 
     It should further be appreciated that the exemplary turbofan engine  10  depicted in  FIG. 1  is by way of example only, and that in other exemplary embodiments, the turbofan engine  10  may have any other suitable configuration, including, for example, any other suitable number of shafts or spools, turbines, compressors, etc. Additionally, or alternatively, in other exemplary embodiments, any other suitable turbine engine may be provided. For example, in other exemplary embodiments, the turbine engine may not be a turbofan engine, and instead may be configured as a turboshaft engine, a turboprop engine, turbojet engine, etc. 
     Referring now to  FIG. 2 , a close-up, schematic view of the combustion section  26  of the turbomachine  16  of the exemplary gas turbine engine  10  of  FIG. 1  is provided along with a tool  100  for insertion into an annular section of the engine  10 . It will be appreciated that although the tool  100  is depicted in  FIG. 2  as being inserted into a combustion section  26 , in other exemplary embodiments, the tool  100  may additionally, or alternatively, be inserted into other areas of the turbofan engine  10  having an annular shape or other shape. In other embodiments, the tool  100  may be inserted into annular sections of the compressor section or the turbine section, or alternatively still, other engines or systems altogether. For example,  FIG. 3  illustrates an embodiment of the tool  100  being inserted into a high pressure (HP) turbine, such as the high pressure turbine  28  previously described. The tool  100  can be inserted into a bore of the engine  10  and passed through the fan section  14 , including fan blades  40 , until reaching an inner portion of the engine  100  corresponding with HP turbine stage-2 C-clips  80 . Certain tool geometry may permit passage of the tool  100  through the high pressure turbine  28  to the desired location of service. The tool  100  can inspect and/or operate on the HP turbine stage 2 C-clips  80  which can be subject to premature failure, resulting in excess aircraft downtime. Additionally or alternatively, still, the tool  100  may be inserted into a non-annular section. For the embodiment of  FIG. 3 , the tool  100  capable of insertion into an annular section of an engine is depicted extending through a borescope into the HP turbine  28 . 
     Referring now also to  FIG. 4 , providing a partial, axial cross-sectional view of the HP turbine  28  of  FIG. 3 , it will be appreciated that the tool  100  generally includes a plurality of segments  102  movable into the engine  10 . Each of the plurality of segments  102  can be aligned so as to form a continuous tool  100 . In the rigidized configuration, the plurality of segments  102  can be coupled together such that the tool  100  has a generally rigid structure. That is, the plurality of segments  102  can act like a rigid body exhibiting sufficient structural stiffness so as to maintain a desired shape while moving and/or operating within the engine  10 , e.g., the HP turbine  28 . As illustrated in  FIG. 4  and according to certain embodiments, the tool  100  can remain in a one- or two-dimensional spatial arrangement. That is, the tool  100  may not twist, e.g., helically, in a third-dimension of, e.g., a cartesian coordinate system. In other embodiments described herein, the tool  100  may exhibit three-dimensional bending. In one or more embodiments, the tool  100  may be inserted into the engine  10  while having a semi-flaccid configuration. In such a manner, the tool  100  may more readily pass through one or more obstacles in the engine  10 . Once past the obstacles, the tool  100  may be fully rigidized. 
     In certain instances, the tool  100  can define one or more linear portions  104  and one or more bent portions  106  when in use. Bent portions  106  can be created, for example, at interfaces  108  between adjacent segments  102 . Alternatively, bent portions  106  can be internal to the shape of at least some of the segments  102 . That is, for example, one or more of the segments  102  can define a bent shape that creates a bend in the tool  100  when in the rigidized configuration. The bent portions  106  can define radii of curvature, e.g., R 1 . The radius of curvature of the illustrated bent portion  106  can be disposed within a single plane. That is, for example, as described above, the radius of curvature of the bent portion  106  of the tool  100  can be defined by a single plane. 
     A distal end  110  of the tool  100  can include an implement, which for the embodiment depicted is a camera  112 , to allow for inspection of various components of the high pressure turbine  28 , like the aforementioned C-clips  80  and the like. It will be appreciated, however, that the insertion tool  100  may include any other suitable implement, such that the insertion tool  100  may be utilized for any suitable purpose. For example, the insertion tool  100  may be utilized to inspect the interior of the engine using, e.g., the camera  112 . Additionally, or alternatively, the insertion tool  100  may include various other tool implements to perform one or more maintenance operations within the interior of the engine (e.g., drilling, welding, heating, cooling, cleaning, spraying, etc.). 
     Further, the exemplary insertion tool  100  can include a drive assembly  114  for driving the insertion tool  100  into, or out of, the interior of the engine, and more specifically for the embodiment shown, into or out of the HT turbine  28 . The drive assembly  114  may be operably coupled to a controller or other control device, such that a length of the insertion tool  100  within the interior of the engine  10  may be controlled with relative precision by the drive assembly  114 . In certain embodiments, the drive assembly  114  can include a motor, servo-motor, or the like configured to drive the tool  100  relative to the engine  10 . In other instances, the drive assembly  114  can include a manual interface configured to permit an operator to manually move the tool  100 . As described hereinafter, the drive assembly  114  can be a selective rigidizer configured to selectively rigidize the tool  100  to a desired shape. 
       FIG. 5  illustrates a perspective view of the tool  100  as seen in accordance with an exemplary embodiment in the flaccid, e.g., non-rigid, configuration. The tool  100  includes segments  102 , such as a first segment  102 A, a second segment  102 B, a third segment  102 C, a fourth segment  102 D, a fifth segment  102 E, a sixth segment  102 F, a seventh segment  102 G, and an eighth segment  102 H. While the illustrated embodiment depicts the tool  100  as including eight segments  102 , the number of segments  102  may be varied. For instance, the tool  100  can include at least two segments, such as at least three segments, such as at least four segments, such as at least five segments, such as at least six segments, such as at least seven segments, such as at least eight segments, such as at least nine segments, such as at least ten segments, such as at least fifteen segments, such as at least twenty segments, such as at least thirty segments, such as at least forty segments, and so on. In an embodiment, at least two of the plurality of segments  102  can have same, or similar, shapes as compared to one another. That is, for instance, the at least two segments  102  can have bodies  114  defining same, or similar, sidewalls  116  and/or ends  118  as compared to one another. In a more particular embodiment, all of the plurality of segments  102  can share a common body shape, or a particular aspect of body shape. For instance, all of the plurality of segments  102  can have the same sidewall lengths, as measured between opposing ends  118 , all of the plurality of segments  102  can have a same general sidewall shape, or the like. In another embodiment, at least two of the plurality of segments  102  can have different shapes as compared to one another. For instance, the bodies  114  of at least two segments can have different lengths as compared to one another, different circumferential dimensions as compared to one another, different ends  118 , or the like. By way of non-liming example, the seventh segment  102 G depicted in  FIG. 5  has a length L 7  that is less than a length L 6  of the sixth segment  102 F. By way of another non-limiting example, the first segment  102 A can be formed of a first material and the second segment  102 B can be formed of a second material different than the first material. By way of yet another non-limiting example, the first segment  102 A can be formed using a particular manufacturing process or manufacturing tolerance different from the manufacturing process or tolerance of the second segment  102 B. For instance, the first segment  102 A can have a lower tolerance, or resolution, than the second segment  102 B. In certain instances, the segments  102  can be formed using an additive manufacturing process, such as three-dimensional printing. The first segment  102 A can have a lower print resolution as compared to the print resolution of the second segment  102 B, the third segment  102 C, and so on. This may occur, for example, where the first segment  102 A is a handle or outermost segment which does not require high surface finish characteristics for sliding over or past features of the engine  10  during navigation therethrough. 
     In one or more embodiments, each pair of adjoining, i.e., neighboring, segments  102  can be attached together through an interface  120 . The interface  120  may be disposed at, or adjacent to, ends  118  of the adjacent segments  102 . Referring, for example, to the interface  120  between the fourth and fifth segments  102 D and  102 E, each interface  120  can be formed from a first hinge member  122  associated with one of the segments, e.g., the fourth segment  102 D, and a second hinge member  124  associated with the adjacent segment, e.g., the fifth segment  102 E. The first and second hinge members  122  and  124  can be joined together to permit relative movement between the adjacent segments  102 , e.g., between the fourth segment  102 D and the fifth segment  102 E. By way of example, the first and second hinge members  122  and  124  can permit relative movement, e.g., rotational movement, of the segments  102  in one or more planes. In a particular embodiment, the interface  120  between a pair of adjacent segments  102  can permit movement of the segments  102  in a single plane. For instance, as illustrated in  FIG. 5 , the fourth and fifth segments  102 D and  102 E can be moveable with respect to one another along a plane corresponding with arrow  126 . That is, the fourth and fifth segments  102 D and  102 E can pivot relative to one another along the directions shown by arrow  126  while staying within a single plane of relative motion. 
     In the illustrated embodiment, the interfaces  120  formed between at least two pairs of adjacent segments  102  can be different from one another. For example, the interface  120  formed between the fourth and fifth segments  102 D and  102 E is disposed in a first plane of rotation while the interface  120  formed between the second and third segments  102 B and  102 C is disposed in a second plane of rotation different from the first plane. Accordingly, the angle of rotation of the interface  120  formed between the third and fourth segments  102 C and  102 D can be different from the angle of rotation of the interface  120  formed between the fourth and fifth segments  102 D and  102 E. In the non-rigid configuration, as illustrated for example in  FIG. 5 , such multi-planar interfacing may not materially affect the flaccid shape of the tool  100 . However, when rigidized, the multi-planar interfacing depicted in  FIG. 5  can result in a tool  100  having a three-dimensional shape for accessing certain areas of the engine  10  or similar structure being serviced (inspected and/or operated upon). 
     A distal segment of the tool  100 , such as the eighth segment  102 H in the depicted embodiment, can have a dissimilar shape as compared to the other segments  102  for purpose of permitting servicing operations. In the illustrated embodiment, the eighth segment  102 H is depicted as having a tapered profile with a minimum width disposed at or adjacent to a distal end  110  of the tool  100 . In such a manner, the tool  100  may be more readily fed into the equipment being serviced, e.g., the aircraft engine. Moreover, the tapered profile may permit the implement, e.g., camera  112 , to exit an internal volume of the tool  100  (described in greater detail below) so as to perform an operation during the service without requiring the diameter of the tool  100  to change. 
       FIGS. 6 and 7  illustrate ends  118  of adjoining, i.e., neighboring, segments  102 . The ends  118  can be matched to one another such that the interface  120  ( FIG. 5 ) therebetween moves in a predetermined manner, e.g., in a predetermined plane as compared to other interfaces  120  formed between other pairs of segments  102 . 
     In an embodiment, the body  114  of at least one of the segments  102  can be formed through an additive manufacturing process, such as by way of non-limiting example, can include three-dimensional printing. Bodies  114  in accordance with some embodiments described herein can thus include indicia of the three-dimensional printing manufacturing process in the form of indicia, including stratum, e.g., layers, formed in the body  114  corresponding with individually stepped printing layers. In certain embodiments described herein, all segments  102  of the tool  100  can be formed using additive manufacturing processes, e.g., three-dimensional printing techniques. In a particular embodiment, the segments  102  can be additively manufactured simultaneously while already in the interfaced configuration. That is, adjacent segments  102  can be additively formed in engaged position relative to one another. 
     Referring initially to  FIG. 6 , the exemplary segment  102  depicted may refer to any one or more of the aforementioned segments  102  (e.g., the first segment  102 A, the second segment  102 B, the third segment  102 C, and so on). The body  114  of the segment  102  defines the first hinge member  122  of the interface  120  ( FIG. 5 ). The first hinge member  122  is laterally offset from a central axis  128  of the body  114  in a radial direction. That is, the first hinge member  122  may not be centrally disposed with respect to the body  114 . In accordance with the particular embodiment depicted in  FIG. 6 , the first hinge member  122  generally includes a central structure  130  and a channel  132  disposed adjacent thereto. The channel  132  is a split channel, including a first channel portion  132 A and a second channel portion  132 B. The central structure  130  is disposed between the first and second channel portions  132 A and  132 B. In an embodiment, the first and second channel portions  132 A and  132 B can have the same, or similar, shapes and/or sizes as compared to one another. In another embodiment, the first and second channel portions  132 A and  132 B can have different shapes and/or sizes as compared to one another. The central structure  130  can define opposite surfaces  134 A and  134 B spaced apart from one another by a thickness of the central structure  130 . The opposite surfaces  134 A and  134 B can form end walls of the first and second channel portions  132 A and  132 B. As described below with respect to  FIG. 7 , the opposite surfaces  134 A and  134 B can be engaged with complementary surfaces of the second hinge member  124  to form the interface  120  between the adjacent segments  102 . 
     The body  114  of the segment  102  illustrated in  FIG. 6  further includes a cavity  136 . The cavity  136  extends through the length of the segment  102  and can emerge from the body  114  at two or more exit locations, such as at exit location  138 . In the illustrated embodiment, the exit location  138  is shown intersecting the first hinge member  122 . That is, for example, the exit location  138  can emerge from the body  114  at an exit location transverse, or generally transverse, to an axis of rotation of the interface  120  through the first hinge member  122 . A second exit location (not illustrated) of the cavity  136  can exit the body  114  of the segment  102  through the a second hinge member of the segment  102 . In such a manner, at least one of the bodies  114  can include both first and second hinge members  122  and  124  and the cavity  136  can exit the body  114  through the first and second hinge members  122  and  124 . The cavity  136  can define a constant, or generally constant, cross-sectional shape along the length of the body  114 . In certain instances, the cavity  136  can be linear, or generally linear. That is, a longitudinal axis of the cavity  136  can lie along a straight, or generally straight line. As described in greater detail below, the cavity  136  can be configured to receive a strength member. The strength member may form a backbone of the tool  100  offset from the central axis  128  of the segments  102  and thus offset from the central axis of the tool  100 . In some embodiments, the strength member can comprise a flexible member, such as, e.g., a tension bearing element, string, memory-laden material defining a predefined shape, or the like. The strength member can allow for flexure of the tool  100  while permitting the tool  100  to return to, e.g., a predefined shape. For example, the tool  100 , in a non-rigid configuration, can slide through a predefined volume of an aircraft engine until reaching a desired location. The tool  100  may have to undergo distortion, e.g., bending, to navigate the predefined volume of the aircraft engine. For instance, the tool  100  may have to slide around corners and through shaped passageways to reach the desired location. The strength member can permit the tool to remain in a single, operable piece for sliding into the airplane engine while preventing the tool from becoming jammed or stopped within the predefined volume. The strength member can put the tool  100  in the predefined shape once the tool is positioned at the desired location to permit operation on the engine. 
     In an embodiment, the strength member can occupy less than an entire areal dimension of the cavity  136 . For example, the strength member can be a hollow tube extending through the cavity  136 . By way of another example, the strength member can have a cross-sectional shape different from the cavity  136  and/or a size that is smaller than the cavity  136 . In such a manner, the cavity  136  can further define space to receive the implement, such as the aforementioned camera  112  therethrough. 
     In an embodiment, the strength member may include a shape memory alloy (SMA) material. In a more particular embodiment, the strength member can be formed entirely from an SMA material. In yet another particular embodiment, the strength member can be at least partially formed from an SMA material. An SMA is generally an alloy capable of returning to its original shape after being deformed. Further, SMAs may act as a lightweight, solid-state alternative to traditional materials. For instance, certain SMAs may be heated in order to return a deformed SMA to its pre-deformed shape. An SMA may also provide varying stiffness, in a predetermined manner, in response to certain ranges of temperatures. The change in stiffness of the shape memory alloy is due to a temperature related, solid state micro-structural phase change that enables the alloy to change from one physical shape to another physical shape. The changes in stiffness of the SMA may be developed by working and annealing a preform of the alloy at or above a temperature at which the solid state micro-structural phase change of the shape memory alloy occurs. The temperature at which such phase change occurs is generally referred to as the critical temperature or transition temperature of the alloy. 
     Some shape memory alloys used herein are characterized by a temperature-dependent phase change. These phases include a martensite phase and an austenite phase. The martensite phase generally refers to a lower temperature phase whereas the austenite phase generally refers to a higher temperature phase. The martensite phase is generally more deformable, while the austenite phase is generally less deformable. When the shape memory alloy is in the martensite phase and is heated to above a certain temperature, the shape memory alloy begins to change into the austenite phase. The temperature at which this phenomenon starts is referred to as the austenite start temperature (As). The temperature at which this phenomenon is completed is called the austenite finish temperature (Af). When the shape memory alloy, which is in the austenite phase, is cooled, it begins to transform into the martensite phase. The temperature at which this transformation starts is referred to as the martensite start temperature (Ms). The temperature at which the transformation to martensite phase is completed is called the martensite finish temperature (Mf). As used herein, the term “transition temperature” without any further qualifiers may refer to any of the martensite transition temperature and austenite transition temperature. Further, “below transition temperature” without the qualifier of “start temperature” or “finish temperature” generally refers to the temperature that is lower than the martensite finish temperature, and the “above transition temperature” without the qualifier of “start temperature” or “finish temperature” generally refers to the temperature that is greater than the austenite finish temperature. 
     In some embodiments, the strength member has a first stiffness at a first temperature and has a second stiffness at a second temperature, wherein the second temperature is different from the first temperature. Further, in some embodiments, one of the first temperature and the second temperature is below the transition temperature and the other one may be at or above the transition temperature. Thus, in some embodiments, the first temperature may be below the transition temperature and the second temperature may be at or above the transition temperature, while in some other embodiments, the first temperature may be at or above the transition temperature and the second temperature may be below the transition temperature. 
     Exemplary but non-limiting examples of SMAs may include nickel-titanium (NiTi) and other nickel-titanium based alloys such as nickel-titanium hydrogen fluoride (NiTiHf) and nickel-titanium palladium (NiTiPd). However, it should be appreciated that other SMA materials may be equally applicable to the current disclosure. For instance, in certain embodiments, the SMA may include a nickel-aluminum based alloys, copper-aluminum-nickel alloy, or alloys containing zinc, copper, gold, and/or iron. The alloy composition may be selected to provide the desired stiffness effect for the application such as, but not limited to, damping ability, transformation temperature and strain, the strain hysteresis, yield strength (of martensite and austenite phases), resistance to oxidation and hot corrosion, ability to change shape through repeated cycles, capability to exhibit one-way or two-way shape memory effect, and/or a number of other engineering design criteria. Suitable shape memory alloy compositions that may be employed with the embodiments of present disclosure may include, but are not limited to NiTi, NiTiHf, NiTiPt, NiTiPd, NiTiCu, NiTiNb, NiTiVd, TiNb, CuAlBe, CuZnAl and some ferrous based alloys. In some embodiments, NiTi alloys having transition temperatures between 5° C. and 150° C. are used. NiTi alloys may change from austenite to martensite upon cooling. 
     The body  114  further includes one or more auxiliary cavities  140 . In an exemplary embodiment, the auxiliary cavities  140  may be disposed on an opposite side of the central axis  128  as compared to the cavity  136 . The one or more auxiliary cavities  140  can include, for example, at least one auxiliary cavity, such as at least two auxiliary cavities, such as at least three auxiliary cavities. In an embodiment, the auxiliary cavities  140  may have one or more same, or similar attributes as compared to one another. For instance, the auxiliary cavities  140  can all share a same radial offset distance from the central axis  128 . In another embodiment, the auxiliary cavities  140  may have one or more different attributes as compared to one another. For instance, the auxiliary cavities  140  can have different diameters as compared to one another. As described in greater detail hereinafter, in certain embodiments the auxiliary cavities  140  may be configured to receive one or more support members. In certain instances, one or more selectively rigidizable element(s), e.g., support member(s) and/or strength member, may operate to selectively rigidize the tool  100  and/or help support the tool  100  in the non-rigidized, i.e., flaccid, configuration. For example, where the support members comprise tension bearing materials, e.g., a string, tensioning the support members can result in the tool  100  taking the rigidized configuration. During tensioning of the support members, adjacent segments of the tool  100  may pivot relative to, e.g., around, interfaces  120  until the support members reach a critical tension whereby the tool is rigidized. In certain instances, the strength member may also be selectively rigidizable by applying tension thereto (e.g.,  FIG. 11 ). In other embodiments, the selectively rigidizable elements can be selectively rigidizable using a non-tensioning method. For example, selective rigidization can occur through a phase shift, chemical and/or electrical stimulation, and the like. 
     A hole  142  can be disposed within the body  114  of at least one of the segments  102 , such as all of the segments  102 , and configured to receive an implement, such as the aforementioned camera  112 , for performing an operation at the desired location. In an embodiment, the hole  142  can be centrally, or generally centrally, located relative to the central axis  128  of the body  114 . In certain instances, the hole  142  can be disposed at a radial position between the cavity  138  and at least one of the auxiliary cavities  140 . The hole  142  can define a non-circular cross section. For instance, the hole  142  can define an ovular cross-sectional profile, a rectangular cross sectional profile, or another shape other than a circle. In certain instances, the hole  142  can be configured to receive an implement, such as a cable connected to a tool, e.g., camera  112 , that has a non-circular cross section. By way of example, the cable can be a ribbon cable or another flat, or generally flat, cable. The cable can be configured to bend in a single, or generally single, axis. That is, for instance, the cable can define a planar shape. The planar shape can bend in a direction perpendicular to the planar shape. The hole  142  can be shaped and/or oriented relative to the direction of movement at the interface  120  ( FIG. 5 ) such that the planar cable bends in a direction associated with a direction of movement, e.g., rotation, at the interface  120 . In an embodiment, the hole  142  can define an aspect ratio [W H :H H ], as defined by a maximum relative width, W H , of the hole  142 , as compared to a maximum relative height, H H , of the hole  142 , that is at least 1.5:1, such as at least 2:1, such as at least 3:1, such as at least 4:1, such as at least 5:1, such as at least 7.5:1, such as at least 10:1, such as at least 15:1, such as at least 20:1. In a particular embodiment, the width and height of the hole  142  can be oriented generally perpendicular with respect to one another. 
       FIG. 7  illustrates an exemplary embodiment of a segment  102  disposed adjacent to the segment  102  illustrated in  FIG. 6 . The segment  102  illustrated in  FIG. 7  includes end  118  having the second hinge member  124  which is configured to engage with the first hinge member  122  described with respect to the segment  102  illustrated in  FIG. 6 . The second hinge member  124  can be complementary in shape and/or size with respect to the first hinge member  122  so as to permit engagement between the adjacent segments  102  illustrated in  FIGS. 6 and 7 . Accordingly, the second hinge member  124  can include a central structure  144  and a ridge  146 . The central structure  144  can be disposed centrally along the ridge  146 . The central structure  144  can split the ridge  146  into a first ridge portion  146 A and a second ridge portion  146 B. The central structure  144  can be indented into the ridge  146  so as to receive the central structure  130  of the first hinge  120 . The central structure  144  can define opposite surfaces  144 A and  144 B configured to couple with surfaces  134 A and  134 B of the first hinge  120  so as to form the interface  120 . 
     The body  114  of the segment  102  can further define a cavity  148  configured to receive the strength member exiting the cavity  138  of the adjacent segment  102 . The cavity  148  can extend through the length of the segment  102  and emerge from the body  114  at two or more exit locations, such as at exit location  150 . In the illustrated embodiment, the exit location  150  is shown intersecting the second hinge member  124 . That is, for example, the exit location  150  can emerge from the body  114  at an exit location transverse, or generally transverse, to an axis of rotation of the interface  120  through the second hinge member  124 . A second exit location (not illustrated) of the cavity  148  can exit the body  114  of the segment  102  through the first hinge member  122  of the segment  102 . In such a manner, the cavity  148  can exit the body  114  through the first and second hinge members  122  and  124 . The cavity  148  can define a constant, or generally constant, cross-sectional shape along the length of the body  114 . In certain instances, the cavity  148  can be linear, or generally linear. That is, a longitudinal axis of the cavity  148  can lie along a straight, or generally straight line. 
     The body  114  further includes one or more auxiliary cavities  152 . In an exemplary embodiment, the auxiliary cavities  152  may be disposed on an opposite side of a central axis  154  as compared to the cavity  148 . The one or more auxiliary cavities  152  can include, for example, at least one auxiliary cavity, such as at least two auxiliary cavities, such as at least three auxiliary cavities. In an embodiment, the auxiliary cavities  152  may have one or more same, or similar attributes as compared to one another. For instance, the auxiliary cavities  152  can all share a same radial offset distance from the central axis  154 . In another embodiment, the auxiliary cavities  152  may have one or more different attributes as compared to one another. For instance, the auxiliary cavities  152  can have different diameters as compared to one another. The auxiliary cavities  152  may be configured to receive the aforementioned one or more support members. 
     A hole  156  can be disposed within the body  114  of the segment  102  and configured to receive the aforementioned implement, e.g., cable, extending through the hole  142  of the adjacent segment  102 . In an embodiment, the hole  156  can be centrally, or generally centrally, located relative to the central axis  154  of the body  114 . In certain instances, the hole  156  can be disposed at a radial position between the cavity  148  and at least one of the auxiliary cavities  152 . The hole  156  can define a non-circular cross section. For instance, the hole  156  can define an ovular cross-sectional profile, a rectangular cross sectional profile, or another shape other than a circle. In certain instances, the hole  156  can be configured to receive an implement, such as a cable connected to a tool, e.g., camera  112 , that has a non-circular cross section. By way of example, the cable can be a ribbon cable or another flat, or generally flat, cable. The cable can be configured to bend in a single, or generally single, axis. That is, for instance, the cable can define a planar shape. The planar shape can bend in a direction perpendicular to the planar shape. The hole  156  can be shaped and/or oriented relative to the direction of movement at the interface  120  ( FIG. 5 ) such that the planar cable bends in a direction associated with a direction of movement, e.g., rotation, at the interface  120 . In an embodiment, the hole  156  can define an aspect ratio [W H :H H ], as defined by a maximum relative width, W H , of the hole  156 , as compared to a maximum relative height, H H , of the hole  156 , that is at least 1.5:1, such as at least 2:1, such as at least 3:1, such as at least 4:1, such as at least 5:1, such as at least 7.5:1, such as at least 10:1, such as at least 15:1, such as at least 20:1. In a particular embodiment, the width and height of the hole  156  can be oriented generally perpendicular with respect to one another. 
     While the above description refers separately to the cavities  136  and  150 , the auxiliary cavities  140  and  152 , and holes  142  and  156 , it should be understood that these aspects can share any common geometry and/or shape as compared to one another. Specifically, the cavities, auxiliary cavities, and holes may be configured to operate together to perform the above-described functions for the tool. As such, these features may be, but are not required to be, common to all segments  102  of the tool  100 . Accordingly, reference to particular aspects with respect to one but not all of these elements as it relates to one segment  102  may refer to that same aspect pertaining to all segments  102 . Additionally, in another embodiment the cavities  136  and  150  may be part of the same cavity, each auxiliary cavity  140  and  152  can be part of the same auxiliary cavity, and holes  142  and  156  can be part of the same hole. That is,  FIG. 6  and  FIG. 7  can illustrate different, e.g., opposite, ends of the same segment  102 . 
       FIG. 8  illustrates an embodiment of the tool  100  in the rigidized configuration. The tool  100  is contained within box  158 . As seen in  FIG. 8 , according to some embodiments of the present disclosure, the tool  100  can define a complex geometry extending through a three dimensional cartesian coordinate system. That is, the tool  100  may simultaneously extend in the X-, Y-, and Z-axis. The particular shape of the tool  100  can be viewed in response to the shape of the environment in which the tool is to be used within. 
     The tool  100  can further include an elongated portion  160  shown in box  162 . The elongated portion  160  may be connected with the tool  100  to elongate the tool  100  for insertion into certain engine components. The elongated portion  160  may be coupled to the tool  100  at a joint  164 . The joint  164  may be a removable joint, such that an operator can install the tool  100  on a plurality of different elongated portions  160  of variable size, shape, or configuration. In certain embodiments, the elongated portion  160  can include a multi-piece construction. For instance, the elongated portion  160  may include a first elongated segment  166  and a second elongated segment  168  coupled together. Accordingly, the operator can select various segments of various shaped, sized, and/or configurations based on the specific application or requirement of the intended use. A handle  170  may be coupled to a proximal end  172  of the elongated portion  160  to permit an operator to hold the tool  100  at a desired location. The handle  170  may include an interface  174  to be engaged with the elongated portion  160 . In a non-illustrated embodiment, the handle  170  may be directly coupled with the tool  100 . That is, the elongated portion  160  may be omitted in accordance with one or more embodiments. 
     The handle  170  may include one or more elements configured to permit selective rigidization of the tool  100 . For example, the handle  170  can include a trigger  176  configured to selectively rigidize the tool  100 . The trigger  176  can be rotatable, pivotal, translatable, or the like between a disengaged configuration in which the tool  100  is flaccid, i.e., non-rigid, and an engaged configuration in which the tool is rigid. In a particular embodiment, the trigger  176  may include finger grips (not illustrated) which permit an operator to maintain positive contact with the trigger  176  when pushing and pulling the trigger between the engaged and disengaged positions. In another particular embodiment, the trigger  176  may include multi-point contact locations, e.g., two discrete finger grip locations. In an embodiment, the trigger  176  may be selectively lockable in the engaged and/or disengaged positions. Accordingly, the operator can rigidize the tool  100  and release the trigger  176  during servicing operations. In yet a further embodiment, the trigger  176  can be operated by a motor or other power device such that rigidization of the tool  100  does not require the generation of manual pressure. The handle  170  may remain exposed from the engine while the tool  100  is inserted in the engine. In such a manner, the operator can maintain control of the tool  100  without direct access thereto. 
     The handle  170  can include an orifice  178  or other interface configured to receive an implement for insertion into the engine. The orifice  178  can include, for example, an opening into which the operator can insert the implement, e.g., the aforementioned camera  112  on a cable, into the engine. In certain embodiments, the orifice  178  may be selectively sealable or closable to prevent ingress of dust and other contaminants from entering the tool  100 . Once opened, the operator can feed and/or move the implement into or relative to the orifice  178  so as to allow for the servicing operation to be performed as required. 
       FIG. 9  illustrates an embodiment of the distal end  110  of the tool  100 . The final segment  102  of the tool  100  disposed at the distal end  110  can include an opening  180  (which may be similar to or the same as the cavity  136  and/or  148 ) in which the camera  112  can extend through. In such a manner, the camera  112  can monitor a leading edge of the tool  100  as it enters the engine and as it performs servicing operations including inspection of the engine and/or repair operations. As previously described, the camera  112  can be disposed within a circumferential boundary of the tool  100 . That is, in accordance with an embodiment, the camera  112  can be disposed within an outer diameter of the segments  102  such that the camera does not create a larger leading edge diameter as compared to the diameter of the segments  102 . The aforementioned holes  142  and  156  can be in communication with a final hole  182  through which an implement, such as a flat cable, can be passed through. As described above, the implement can be hand, or machine, fed through the orifice  178  ( FIG. 8 ) to the distal end  110  for performing the servicing operation. 
       FIGS. 10 and 11  illustrate an embodiment of an insertion tool  1000  with a strength member  1002  extending through cavities  1004  of adjacent segments  1006 . The strength member  1002  illustrated in  FIGS. 10 and 11  includes a plurality of strength members, such as at least two strength members, such as at least three strength members. However, the strength member  1002  may alternatively include a single strength member. The insertion tool  1000  is illustrated in the non-rigidized configuration wherein the segments  1006  are not coupled together at a fixed angular disposition. That is, the adjacent segments  1006  can readily move relative to each other.  FIG. 12  illustrates the insertion tool  1000  with segments  1006  fixedly coupled together by the strength member  1002 . Selectively rigidizing the tool  1000 , i.e., transitioning from the non-rigidized configuration illustrated in  FIGS. 10 and 11 , to the rigidized configuration illustrated in  FIG. 12 , can occur, for example, by tensioning the strength member  1002  and/or one or more support members  1016  disposed opposite the cavities  1004 . As tension is applied, the length of the strength member  1002  and/or support members  1016  within the tool  1000  can decrease, effectively pulling adjacent segments  1006  together in the direction shown by arrows  1008  ( FIG. 11 ). As the segments  1006  come into contact with one another, internal tension within the strength member  1002  and/or support members  1016  increases, thereby maintaining the segments  1006  connected together, and effectively rigidizing the tool  1000 . Ends  1010  of the segments  1006  can be keyed together to prevent relative movement in the rigidized configuration. Keyed ends  1010  can include complementary face characteristics that, when combined, prevent relative movement, e.g., rotation, between the adjacent segments  1006 . By way of non-limiting example, the keyed ends  1010  can include complementary posts and recesses, complementary undulating features, complementary castellations, and the like. As the complementary features are mated with one another, the adjacent segments  1006  can become fixed relative to one another and maintained at their fixed relative position by tension within the strength member  1002 . 
     In the illustrated embodiment, the adjacent pair of depicted segments  1006  include complementary ridges  1012  and channels  1014  configured to align with one another in the rigidized configuration. In addition to securing the segments  1006  at relatively fixed positions with respect to one another, the ridges  1012  and channels  1014  can act as hinges for the segments  1006  when the strength member  1002  is less than fully tensioned. That is, for instance, when tension on the strength member  1002  is lessened, the segments  1006  may deflect relative to one another. If tension is maintained above a certain amount, such that the ridges  1012  and channels  1014  do not fully unseat from one another, the segments  1006  may move within a guided track relative to each other about a pivot axis formed by the ridges  1012  and channels  1014 . This may be advantageous during insertion of the tool  1000  into the engine  10  as the tool  1000  may be forced to navigate complex geometry within the engine which requires the tool  1000  to bend while simultaneously retaining some amount of rigidity. 
     As previously described, selective rigidization of the tool  1000  can occur through use of one or more support members  1016 . The one or more support members  1016  can extend through auxiliary cavities  1018  of the segments  1006 . The support members  1016  can help retain the segments  1006  together, for instance, when the strength member  1002  is in the non-fully tensed state. The support members  1016  can further assist in guiding the tool  1000  within the engine  10  during the tool insertion process. The support members  1016  can also be used to selectively rigidize the tool  1000  while the strength member  1002  forms a flexible backbone for the tool  1000 . 
     As described with respect to  FIGS. 6 and 7 , adjacent segments  102  of the tool may be joined together at interface  120  by one or more hinge members, e.g., a first hinge member  122  and a second hinge member  124 . The first and second hinge members  122  and  124  can act together to connect the segments  102  while permitting relative movement therebetween, particularly when the tool  100  is not rigidized. The first and second hinge members  122  and  124  described with respect to  FIGS. 6 and 7  are held together through interference fit. In particular, surfaces  134 A and  134 B engage with surfaces  144 A and  144 B, respectively, to dynamically hold adjacent segments  102  together.  FIGS. 13 to 18  depict alternate embodiments of the interface  120  and associated hinges  122  and  124 . 
       FIG. 13A  illustrates an enlarged view of an interface  120  formed between adjacent segments  102  in accordance with an exemplary embodiment.  FIG. 13B  illustrates an enlarged, cross-sectional view of the interface as seen along Line A-A in  FIG. 13A . Referring initially to  FIG. 13A , the segments  102  can define first and second hinge members  122  and  124  as described above. The first and second hinge members  122  and  124  can cooperatively mate with one another to permit selectively flexure between the segments  102 . 
     In one or more embodiments, the first and second hinge members  122  and  124  can be integrally formed with the body  114  of the segment  102 . In a particular embodiment, the segments  102 , including the first and second hinge members  122  and  124 , can be formed using an additive manufacturing process, such as for example, three-dimensional printing, resulting in a stratum including a plurality of layers. In yet a more particular embodiment, the segments  102  can be formed in the assembled state such that adjacent segments  102  are, e.g., additively manufactured with the resulting interfaces  120  formed during the manufacturing process and ready for use. While additively manufacturing the interfaces  120  with the first and second hinge members  122  and  124  assembled may reduce the introduction of weakness into the bodies  114  resulting from flexing the bodies to install the first and second hinge members  122  and  124  relative to one another, certain additive manufacturing processes can also result in the formation of excess material left at the interface  120 . For instance, certain three-dimensional printing processes utilize printing powder which is formed into the final shape of the structure being printed. Not all of the printing powder may solidify, resulting in powder being caught within the interface  120 . Such stray powder can reduce efficiency of the tool  100 , potentially resulting in premature wear and/or failure while the tool  100  is disposed within the engine  10  or even result in powder being deposited in the engine as the tool  100  navigates therethrough during insertion therein. 
     To mitigate the confluence of powder within the interface  120 , the first and second hinge members  122  and  124  can be shaped so as to have a powder gap  184  configured to permit powder to pass therethrough. In particular, the powder gap  184  may permit passage of powder through the powder gap  184  when the tool  100  is flexed or otherwise deformed. Referring to  FIG. 13B , the powder gap  184  may be formed by a gap between the first and second hinge members  122  and  124 . Powder  186  can exit the interface  120  through the powder gap  184  in a direction corresponding, for example, with arrow  188 . To further enhance powder removal from the interface  120 , in certain instances at least one of the first and second hinge members  122  and  124  can have a tapered interface profile. For instance, an inner sidewall  190  of the second hinge member  124  can have an outward tapered profile. The inner sidewall  190  can define a taper angle, β, as measured with respect to a normal axis  194 , of at least one degree, such as at least two degrees, such as at least three degrees, such as at least four degrees, such as at least five degrees, such as at least six degrees, such as at least seven degrees, such as at least eight degrees, such as at least nine degrees, such as at least ten degrees, such as at least fifteen degrees. In another embodiment, the outer sidewall  192  of the first hinge member  122  can have an inward tapered profile. The outer sidewall  194  can define a taper angle, α, as measured with respect to the normal axis  194 , of at least one degree, such as at least two degrees, such as at least three degrees, such as at least four degrees, such as at least five degrees, such as at least six degrees, such as at least seven degrees, such as at least eight degrees, such as at least nine degrees, such as at least ten degrees, such as at least fifteen degrees. In certain instances, α can be equal, or approximately equal, with β. In other instances, α and β can be different from one another. In an embodiment, the inner sidewall  190  and the outer sidewall  192  can be angularly offset from one another. 
       FIG. 14A  illustrates an enlarged view of an interface  120  formed between adjacent segments  102  in accordance with another exemplary embodiment when the tool  100  is in a rigid, or semi-rigid, configuration.  FIG. 14B  illustrates an enlarged view of the interface  120  of  FIG. 14A  when the tool is in a non-rigid configuration, i.e., the segments  102  are not rigidly held together and have moved relative to one another. The interface  120  depicted in  FIGS. 14A and 14B  is multi-modal. Multi-modal interfacing can include instance of close-fit and other instances of loose fit. In the rigid configuration, the first and second hinge members  122  and  124  have a close-fitting arrangement whereby accurate alignment between the segments  102  occurs. In the non-rigid configuration, the first and second hinge members  122  and  124  can have a loose fit whereby the interface  120  is relaxed. Close-fitting arrangement can be the result of hinge geometry. For instance, the first hinge member  122  can define an elongated length, L 1 , and the second hinge member  124  can define an elongated length, L 2 . In the rigid configuration, L 1  and L 2  can be offset from one another. For instance, L 1  and L 2  can be rotationally offset from one another by at least one degree, such as at least two degrees, such as at least three degrees, such as at least four degrees, such as at least five degrees, such as at least six degrees, such as at least seven degrees, such as at least eight degrees, such as at least nine degrees, such as at least ten degrees, such as at least fifteen degrees, such as at least twenty degrees, such as at least thirty degrees, such as at least forty degrees, such as at least fifty degrees, such as at least sixty degrees, such as at least seventy degrees, such as at least eighty degrees, such as at least ninety degrees. In the non-rigid configuration, L 1  and L 2  can be offset from one another by an amount less than in the rigid configuration. By way of non-limiting example, in a particular embodiment L 1  and L 2  can be offset from one another by ninety degrees in the rigid configuration and offset by less than ninety degrees in the non-rigid configuration. 
     In an embodiment, the first hinge member  122  comprises a post  210  and the second hinge member  124  comprises a recess  212  into which the post  210  is insertable. At least one of the post  210  and recess  212  can have an aspect ratio different than 1:1, wherein the aspect ratio is defined by a length of the post  210  and/or recess  212 , e.g., L 1 , relative to a width thereof, as measured perpendicular to the length. That is, for example, at least one of the first and second hinge members  122  and  124  can have an elongated shape. 
       FIG. 15A  illustrates an enlarged view of an interface  120  formed between adjacent segments  102  in accordance with another exemplary embodiment.  FIG. 15B  illustrates an enlarged view of the interface  120  between adjacent segments  102  as seen in a disconnected configuration for purpose of viewing the first and second hinge members  122  and  124 . In an embodiment, the first and second hinge members  122  and  124  can be configured to be connected to one another when the adjacent pair of segments  102  are disposed at a first orientation with respect to one another. After adjusting the adjacent pair of segments  102  to a second orientation different from the first orientation, the adjacent pair of segments  102  can remain coupled together. This type of engagement may be described as displaced-to-lock engagement. By way of example, the displacement can include angular displacement. The angular displacement between the first and second orientations can be at least 1°, such as at least 2°, such as at least 3°, such as at least 4°, such as at least 5°, such as at least 10°, such as at least 20°, such as at least 30°, such as at least 40°, such as at least 50°, such as at least 60°, such as at least 70°, such as at least 80°. The displacement can also include translation, pivoting, the like, or any combination thereof. 
     In the embodiment illustrated in  FIG. 15B , the first hinge member  122  includes receiving structure  196  comprising a first side surface  198  and a second side surface  200 . The first and second side surfaces  198  and  200  can extend from at least one of opposite side surfaces  134 A and  134 B of the first hinge member  122 . The first and second side surfaces  198  and  200  define a gap  202  that extends therebetween. The second hinge member  124  includes a projection  204  configured to be passed through the gap  202  when the segments are oriented relative to one another at the first orientation and retained between the first and second side surfaces  198  and  200  when the segments  102  are oriented relative to one another at the second orientation. A retaining element  206  can additionally be passed through the gap  202  when the first and second hinge members  122  and  124  are joined together in the first orientation. In the connected (i.e., engaged) configuration resulting from reorienting the segments  102  to the second orientation, the retaining element  206  can interface with the first side surface  198  to further support and maintain engagement between the segments  102 . In an embodiment, the receiving structure  196  can be approximately the same on opposite side surfaces  134 A and  134 B of the first hinge member  122 . In another embodiment, the projection  204  and retaining element  206  can be approximately the same on both opposite side surfaces  144 A and  144 B of the second hinge member  124 . 
       FIG. 16A  illustrates an enlarged view of an interface  120  formed between adjacent segments  102  in accordance with another exemplary embodiment.  FIG. 16B  illustrates an enlarged view of the interface  120  between adjacent segments  102  as seen in a disconnected configuration for purpose of viewing the first and second hinge members.  FIG. 16C  illustrates a cross-sectional view of the interface  120  between adjacent segments  102  as seen along Line C-C in  FIG. 16A . The interface  120  includes a compliance feature  208  disposed between opposite side surfaces  144 A and  144 B of the second hinge member  124 . The compliance feature  208  can permit expansion between the opposite side surfaces  144 A and  144 B during assembly of the segments  102 . In an embodiment the compliance feature  208  can include a slit extending into the body  114  of the segment. The slit can define a length of at least 0.1 mm, such as at least 0.2 mm, such as at least 0.3 mm, such as at least 0.4 mm, such as at least 0.5 mm, such as at least 1 mm, such as at least 2 mm, such as at least 3 mm, such as at least 4 mm, such as at least 5 mm. As the first and second hinge members  122  and  124  are brought together so as to be engaged with one another, a diameter of the slit can increase, allowing the opposite surfaces  134 A and  134 B to pass over and onto the opposite side surfaces  144 A and  144 B. In an embodiment, the opposite surfaces  134 A and  134 B of the first hinge member  122  can be complementary to opposite side surface  144 A and  144 B of the second hinge member  124 . Complementary side surfaces can include, for example, flat surfaces, conical surface, hemispherical surfaces, and the like which fit together so as to maintain the first and second hinge members  122  and  124  coupled together at the interface  120 . 
     In accordance with one or more embodiments described herein, the first and second hinge members  122  and  124  can be configured to float relative to one another. As used herein, “float relative to one another” refers to an interface whereby two or more members, such as the first and second hinge members  12  and  124  of adjacent segments  102 , are not fixedly coupled together and can move relative to one another, e.g., in the relaxed state. Instead, the adjacent segments  102  are held together, for example, by the strength member and/or support member, i.e., in the selectively rigidized state. Conversely, in certain instances, when tension is removed, the adjacent segments  102  may separate from one another when the first and second hinge members  122  and  124  float relative to one another. 
     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 language of the claims. 
     Further aspects of the invention are provided by the subject matter of the following clauses: 
     Embodiment 1. An insertion tool for performing an operation on equipment, the insertion tool comprising: a plurality of segments, each segment of the plurality of segments including a body comprising: a first hinge member; and a second hinge member, the first hinge member of a first segment being coupled to the second hinge member of a second segment adjacent to the first segment through an interface, wherein the interface comprises a powder gap, a multi-modal interface, a compliance feature, a displace-to-lock configuration, an interference fit, or any combination thereof. 
     Embodiment 2. The insertion tool of any one or more of the embodiments, wherein the body of at least one of the segments comprises a stratum comprising a plurality of layers. 
     Embodiment 3. The insertion tool of any one or more of the embodiments, wherein the insertion tool comprises a strength member transversely intersecting the interface. 
     Embodiment 4. The insertion tool of any one or more of the embodiments, wherein the powder gap is disposed between an outer sidewall of the first hinge member and an inner sidewall of the second hinge member. 
     Embodiment 5. The insertion tool of any one or more of the embodiments, wherein the inner and outer sidewalls are angularly offset from one another. 
     Embodiment 6. The insertion tool of any one or more of the embodiments, wherein the multi-modal interface comprises a close fit when the adjacent segments are rigidized by the strength member and a loose fit when the adjacent segments are not rigidized by the strength member. 
     Embodiment 7. The insertion tool of any one or more of the embodiments, wherein the first hinge member comprises a post and the second hinge member comprises a recess into which the post is insertable, and wherein at least one of the post and recess have an aspect ratio different than 1:1. 
     Embodiment 8. The insertion tool of any one or more of the embodiments, wherein the first hinge member comprises a first outer surface and a second outer surface, wherein the second hinge member comprises a first inner surface and a second inner surface, and wherein the interface comprises a hemispherical interface between the first outer surface and the first inner surface and a hemispherical interface between the second outer surface and the second inner surface. 
     Embodiment 9. The insertion tool of any one or more of the embodiments, wherein the displace-to-lock interface comprises a projection of the second hinge member configured to pass through a gap between adjacent side surfaces of a receiving structure of the first hinge member. 
     Embodiment 10. An insertion tool for performing an operation on equipment, the insertion tool comprising: a plurality of segments, each segment of the plurality of segments including a body comprising: a first hinge member; and a second hinge member, the first hinge member of a first segment being coupled to the second hinge member of a second segment adjacent to the first segment through an interface, wherein the interface comprises a powder gap, a multi-modal interface, a compliance feature, a displace-to-lock configuration, an interference fit, or any combination thereof; and a strength member intersecting the interface. 
     Embodiment 11. The insertion tool of any one or more of the embodiments, wherein the strength member comprises a backbone of the insertion tool configured to maintain the plurality of segments coupled together when the insertion tool is not rigidized. 
     Embodiment 12. A method of forming an insertion tool, the method comprising: additively forming bodies of segments of the insertion tool; and flexing adjacent segments of the insertion tool relative to one another such that powder contained at an interface between adjacent segments of the insertion tool can pass from the interface through a powder gap. 
     Embodiment 13. The method of any one or more of the embodiments, wherein flexing adjacent segments of the insertion tool is performed by tensioning a strength member extending between the adjacent segments. 
     Embodiment 14. The method of any one or more of the embodiments, wherein the adjacent segments include a first segment having a first hinge member and a second segment having a second hinge member, and wherein the first and second hinge members define the interface between the first and second segments. 
     Embodiment 15. The method of any one or more of the embodiments, wherein the first and second hinge members are configured to move relative to one another when the tool is not rigidized. 
     Embodiment 16. The method of any one or more of the embodiments, wherein the interface further comprises a multi-modal interface, a compliance feature, a displace-to-lock configuration, an interference fit, or any combination thereof. 
     Embodiment 17. The method of any one or more of the embodiments, wherein additively forming the bodies comprises three-dimensional printing. 
     Embodiment 18. The method of any one or more of the embodiments, further comprising rigidizing the insertion tool by applying force to the strength member. 
     Embodiment 19. The method of any one or more of the embodiments, wherein the adjacent segments are configured to rotate by an engagement displacement between rigidized and non-rigidized configurations, and wherein flexing adjacent segments of the insertion tool relative to one another such that powder contained at the interface between adjacent segments of the insertion tool can pass from the interface through the powder gap is performed by rotating the adjacent segments by a rotational displacement no greater than the engagement displacement. 
     Embodiment 20. The method of any one or more of the embodiments, further comprising coupling the adjacent segments together after additively manufacturing the bodies of the segments.