Tubular structure

Abstract

The tubular structure (104), system, and method are generally directed to a support structure having structural properties similar to thick-walled structures while being formed using material having a thickness suitable for rolling and welding, and thus useful for rapid, cost-effective manufacturing. In particular, the tubular structure includes a tubular base (106) and a wrap (108) supported on the base.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 62 / 966,803, filed January 28, 2020, the entire contents of which are incorporated herein by reference. [Background technology]

[0002] Many applications of large support structures have thick tubular walls. For example, offshore wind turbines require large, thick-walled (heavy-walled) support towers and piles because of their large size and high loads. The process for fabricating these support structures is costly and time-consuming, requiring rolling and welding thick steel plates (e.g., 30 mm to 100 mm). Rolling plates of such thickness requires the use of expensive specialized equipment to generate large forces. Welding the thick plates also requires multiple welding passes, making the process very long and therefore increasing manufacturing costs.

[0003] There is therefore a need to create a support structure that is suitable for rapid, cost-effective manufacturing while at the same time being capable of withstanding high loads.

[0004] overview The tubular structures, systems and methods are generally directed to support structures that are formed using materials having a thickness suitable for rolling and welding, and thus lend themselves to rapid, cost-effective manufacturing, while at the same time having structural properties similar to thicker-walled structures.

[0005] According to one embodiment, a tubular structure includes a base having opposing first and second surfaces, the first surface defining an elongated cavity and having a tubular shape defining a longitudinal axis extending along the elongated cavity, and a wrap supported on the second surface of the base, the wrap including at least one layer, each layer having a first longitudinal edge and a second longitudinal edge associated with the given layer and joined to each other along a respective helical seam extending around the longitudinal axis of the base.

[0006] In some implementations, the combined thickness of the wrap and base can vary in a direction parallel to the longitudinal axis of the base. For example, the thickness of the wrap varies in a direction parallel to the longitudinal axis of the base. Additionally or alternatively, the thickness of the base is substantially constant in a direction parallel to the longitudinal axis of the base. Additionally or alternatively, the thickness of the wrap can vary monotonically in a direction parallel to the longitudinal axis of the base. As an example, the tubular shape of the base includes a frustoconical shape that tapers in a direction parallel to the longitudinal axis, and the thickness of the wrap decreases monotonically in the direction of the taper of the frustoconical shape.

[0007] In certain implementations, the at least one layer can be a plurality of layers, the plurality of layers being stacked at least partially on top of one another in a radial direction. For example, each layer of the plurality of layers can encircle the base at least once. Additionally or alternatively, the number of layers of the plurality of layers can vary in a direction parallel to the longitudinal axis of the base. Additionally or alternatively, each layer of the plurality of layers can be bonded to the base, to at least one other layer of the plurality of layers, or a combination thereof. Additionally or alternatively, each layer of the plurality of layers can be welded to the base, to another layer of the plurality of layers, or a combination thereof. In some cases, the individual spiral seams of a given layer can be longitudinally offset from the individual spiral seams of the layers adjacent to the given layer.

[0008] In some implementations, the base can include a seam that extends about a longitudinal axis of the base. For example, each spiral seam of the at least one layer of the wrap can be spaced longitudinally from a seam of the base along the longitudinal axis. Additionally or alternatively, the seam of the base can be parallel to each spiral seam of the at least one layer of the wrap.

[0009] According to another aspect, a system for forming a tubular structure includes a drive system including a drive roll operable to move a feedstock material in a planar form in a feed direction, a bending device disposed to receive the feedstock material in the planar form moving in the feed direction and controllable to bend the feedstock material in the planar form to produce a curved form, a plurality of support rollers operable to rotatably support a curved surface of the material, and one or more pressure rolls disposed to receive the curved form of the feedstock material from the bending device, the one or more pressure rolls being movable to press the curved form of the feedstock material from the bending device onto the curved surface of the material rotatably supported on the plurality of support rollers. In some implementations, the system can further include a bonding device disposed to bond the curved form of the feedstock material to itself, to the curved surface rotatably supported on the plurality of support rollers, or a combination thereof. Additionally or alternatively, the system may further include a guiding system arranged to receive the curved form of the feedstock material from the bending device, the guiding system including an actuator controllable to wrap the curved form of the feedstock material along the respective helical seam of a given layer of the tubular structure being formed. The actuator may include, for example, one or more edge guides, one or more edge rollers, one or more pinch rollers, or a combination thereof. In some cases, the guiding system may further include a sensor configured to detect a parameter indicative of a position of the curved form of the feedstock material along the respective helical seam, the actuator in electrical communication with the sensor, the actuator adjustable based on a signal from the sensor to adjust a position of the curved form of the feedstock material along the respective helical seam of a given layer of the tubular structure being formed.

[0010] According to another aspect, a method of forming a tubular structure can include bending a portion of a strip of stock material in a planar configuration into a curved configuration, wrapping the curved configuration of the stock material over a curved surface of a base to form a helical seam about a longitudinal axis defined by the base, and joining the curved configuration of the stock material to at least itself along the helical seam.

[0011] In certain implementations, wrapping the blank material in a curved form onto the curved surface of the base can include pressing the blank material in a curved form onto the curved surface of the base.

[0012] In some implementations, joining the curved form of the blank material to at least itself along the spiral seam can include joining the curved form of the blank material to a curved surface of the base.

[0013] In certain implementations, joining the curved form of the blank material to at least itself can include welding the curved form of the blank material to itself along a helical seam.

[0014] According to another aspect, a system for forming a tubular structure can include a tension roller positionable in contact with the feedstock material in planar form as it moves in a feed direction; a rotator operable to rotate a curved surface of the base about a longitudinal axis defined by the base; a guide system including an actuator controllable to wrap the feedstock material in planar form along a helical seam about the longitudinal axis of the base; and a joining device positioned to join the feedstock material at least to itself along the helical seam as the tubular structure is formed.

[0015] In some implementations, the actuator may include one or more edge guides, one or more edge rollers, one or more pinch rollers, or a combination thereof.

[0016] In certain implementations, the guidance system can further include a sensor configured to detect a parameter indicative of a position of the blank material along the helical seam, the actuator being in electrical communication with the sensor, the actuator being adjustable based on a signal from the sensor to adjust the position of the blank material in the planar form along the helical seam as the tubular structure is formed.

[0017] According to yet another aspect, a method of forming a tubular structure can include joining a plurality of sheets in a nonlinear butt engagement with one another to produce a blank in a planar configuration, fastening the blank to a curved surface of a base defining a longitudinal axis, and rotating the curved surface of the base about the longitudinal axis of the base while the blank is fastened to the base, the rotation of the curved surface of the base bending the blank in a planar configuration around the curved surface of the base while a first longitudinal edge and a second longitudinal edge of the blank form at least one helical seam about the longitudinal axis of the base. In some implementations, the method can further include moving the blank in a planar configuration through one or more tension rollers while the blank is fastened to the base and the curved surface of the base is rotating about the longitudinal axis. Additionally or alternatively, the method can further include joining the blank at least to itself along at least one helical seam. In some cases, joining the base material at least to itself along at least one spiral seam can further include joining the layer of base material to a curved surface of the base, to a previous layer of base material, or a combination thereof.

[0018] According to yet another aspect, a tubular structure can include a first shell, a second shell having a frustoconical shape, the first shell nested within the second shell with the first shell and the second shell defining a gap therebetween, and a stabilizer disposed in the gap, the stabilizer maintaining the position of the first shell and the second shell relative to one another.

[0019] In some implementations, the first shell can be substantially parallel to the second shell along a longitudinal axis defined by the first shell.

[0020] In certain implementations, the stabilizer can include a filler material coupled to the first shell, to the second shell, or a combination thereof.

[0021] In some implementations, the stabilizer can include a plurality of structural elements extending through the gap and coupled to each of the first and second shells. For example, the first shell can define a plurality of first holes, the second shell can define a plurality of second holes aligned with the plurality of first holes, and each of the plurality of structural elements can extend through one of the plurality of first holes and a corresponding one of the plurality of second holes.

[0022] According to yet another aspect, a tubular structure can include a shell having a first surface and a second surface, the first surface defining an elongated cavity and the first surface opposing the second surface, the shell having a tubular shape defining a longitudinal axis extending along the elongated cavity and having a helical seam extending about the longitudinal axis, and a plurality of elongated ribs coupled to the shell with a longitudinal dimension of each elongated rib substantially parallel to the longitudinal axis defined by the tubular shape of the shell.

[0023] In some implementations, the tubular shape of the shell can be frusto-conical.

[0024] In certain implementations, at least one of the plurality of elongated ribs may be secured along a first surface of the shell.

[0025] In some implementations, at least one of the plurality of elongated ribs may be secured along the second surface of the shell.

[0026] In certain implementations, the elongated ribs may be joined to one another along longitudinal joints that are substantially coplanar with a longitudinal axis defined by the tubular shape of the shell.

[0027] In some implementations, each of the plurality of elongated ribs can be V-shaped with a first leg and a second leg joined to each other at an apex, the first leg and the second leg being joined to the shell. [Brief description of the drawings]

[0028] [Figure 1A] FIG. 1 is a perspective view of a wind turbine assembly including a tubular structure.

[0029] [Figure 1B] FIG. 1B is a side view of the tubular structure of FIG. 1A.

[0030] [Figure 1C] 1C is a vertical cross-sectional view of the tubular structure of FIG. 1A, with the cross-section taken along line 1C-1C of FIG. 1B.

[0031] [Figure 1D] FIG. 1D is a close-up of the tubular structure along area 1D of detail in FIG. 1C.

[0032] [Figure 2A] FIG. 1 is a block diagram of a manufacturing system for forming a tubular structure.

[0033] [Figure 2B] 2B is a schematic diagram of a wrapping process performed by the manufacturing system of FIG. 2A.

[0034] [Diagram 3] 1 is a flow diagram of an exemplary method of forming a tubular structure.

[0035] [Figure 4A] FIG. 1 is a block diagram of a manufacturing system for forming a tubular structure.

[0036] [Figure 4B] 4B is a schematic diagram of a winding process performed by the manufacturing system of FIG. 4A.

[0037] [Diagram 5] 1 is a flow diagram of an exemplary method of forming a tubular structure.

[0038] [Figure 6A] FIG. 1 is a perspective view of a tubular structure including a first shell, a second shell, and a filler therebetween.

[0039] [Figure 6B] FIG. 6B is a perspective view of the tubular structure of FIG. 6A, shown with a portion of the tubular structure removed.

[0040] [Figure 7A] FIG. 1 is a perspective view of a tubular structure including a first shell, a second shell, and a number of structural elements extending therebetween.

[0041] [Figure 7B] FIG. 7B is a side view of the tubular structure of FIG. 7A.

[0042] [Figure 7C] FIG. 7B is a cross-sectional top view of the tubular structure, with the cross-section taken along line 7B-7B of FIG.

[0043] [Figure 8A] FIG. 1 is a perspective view of a tubular structure including a shell and a plurality of elongated ribs coupled to the shell.

[0044] [Figure 8B] FIG. 8B is a top view of the tubular structure of FIG. 8A.

[0045] [Figure 8C] FIG. 8B is a perspective view of an elongated rib of the tubular structure of FIG. 8A.

[0046] Like reference numbers in the various drawings indicate like elements.

[0047] explanation The embodiments will now be described in more detail below with reference to the accompanying drawings, in which example embodiments are shown, however, the embodiments may be embodied in many different forms and should not be construed as limited to the example embodiments set forth herein.

[0048] All documents mentioned herein are incorporated herein by reference in their entirety. Reference to a singular item should be understood to include the plural item, and vice versa, unless expressly stated otherwise or apparent from the context. Grammatical conjunctions are intended to refer to any and all disjunctive and conjunctive combinations of joined clauses, sentences, words, and the like, unless expressly stated otherwise or apparent from the context. Thus, the term "or" should generally be understood to mean "and / or" and the term "and" should generally be understood to mean "and / or."

[0049] The description of ranges of values ​​herein is not intended to be limiting, but instead refers to any and every value within the range individually, unless otherwise indicated herein, and each separate value within such range is incorporated into the present specification as if it were individually recited herein. The words "about," "approximately," or the like, when used with numerical values, should be interpreted to include any deviations as would be understood by a person skilled in the art to operate satisfactorily for the intended purpose. Ranges of values ​​and / or numerical values ​​are provided herein as examples only and do not constitute limitations on the scope of the described embodiments. The use of any and all examples or exemplary words (such as, for example, or the like) is intended merely to better describe the present embodiments and does not pose limitations on the scope of these embodiments. The absence of language herein should be interpreted to indicate any element not recited in the claims as essential to the practice of the disclosed embodiments.

[0050] As used herein, the term "tubular structure" should be understood to include any aspect or form of a structure having a substantially curvilinear two-dimensional profile about a longitudinal axis that defines and extends along an elongated cavity. Thus, unless otherwise specified or clear from the context, some examples of tubular structures include frustoconical and cylindrical (e.g., right circular cylinders). Unless otherwise indicated, tubular shapes described herein may include shapes that approximate a geometric ideal, such as a curvilinear, frustoconical, conical, or cylindrical shape. Such approximations of a geometric ideal may include approximations of a frustoconical shape with deviations from the geometric ideal resulting from stacking layers of material and / or typical manufacturing tolerances.

[0051] Furthermore, as used herein, the term "thickness" and variations thereof should be understood and taken in context to generally mean the wall thickness of a given material. For example, with respect to a single layer, thickness should generally be understood to mean the wall thickness of a single layer unless otherwise specified or clear from the context. Additionally or alternatively, with respect to multiple layers, thickness should be understood to mean the total thickness of multiple layers wound on top of each other, unless the contrary usage is indicated. Additionally or alternatively, with respect to the tubular structures described herein, thickness should be understood to mean the total thickness of the tubular structure at a given point along the longitudinal axis, and thus may mean the wall thickness of the base only, or the combined thickness of the base supporting the wrap, as the case may be at a given point along the longitudinal axis.

[0052] Furthermore, as used herein, the terms "longitudinal" and "radial" should be understood to mean directions in a cylindrical coordinate system, unless a contrary intention is clear from the context. Thus, in particular, reference to a radial direction should be understood to mean a direction perpendicular to the longitudinal axis. Additionally or alternatively, a longitudinal direction associated with such a cylindrical coordinate system should be understood to be parallel to a longitudinal axis associated with the structure being described. It should be recognized that, although the longitudinal axis may correspond to the central axis of any given structure, this need not necessarily be the case in a particular implementation.

[0053] The apparatus, systems, and methods of the present disclosure are described in the context of tubular structures useful as towers for large wind turbines (e.g., offshore wind turbines) capable of withstanding high loads. More specifically, for the benefit of clear and efficient description, aspects of the present disclosure are generally described in the context of frustoconical shapes, but should be understood to be equally applicable to cylinders, unless a contrary intention is indicated. Furthermore, for clarity of illustration, the tubular structures are shown as unitary structures. However, unless a contrary intention is indicated, it should be understood that any one or more of the various different frustoconical shapes described herein can be manufactured in assembled pieces according to the dimensional requirements of a given end use. Furthermore, unless otherwise specified or clear from the context, such tubular structures described herein can be used in any one or more of a variety of different applications requiring high strength and / or high stiffness, such as tubular structures useful for piles or other support structures for wind turbines, or more generally for large civil engineering structures, pipelines, pressure vessels, and the like.

[0054] 1A-1D, a wind turbine assembly 100 can include a wind turbine 102 and a tubular structure 104. The wind turbine 102 can be supported by the tubular structure 104, where the tubular structure 104 withstands loading conditions associated with the movement of the wind turbine 102 and the installation environment. In some cases, the tubular structure 104 can have a diameter that decreases along its length such that the top, where the wind turbine 102 is attached, has a smaller diameter than the bottom, where the tubular structure 104 is fixedly secured to the ground or other rigid surface. Longitudinally tapering the diameter of the tubular structure 104 can be useful, for example, to address competing considerations of efficient use of materials while providing structural strength to support loads applied to the tubular structure 104 in the field. However, the strength profile achievable using longitudinal tapering may be subject to certain limitations (e.g., dimensional constraints associated with transportation and / or installation). Thus, as described in more detail below, the thickness of the material of the tubular structure 104 may additionally or alternatively be varied to facilitate achieving a predetermined strength profile of the tubular structure 104 while steering around practical considerations such as installation time and cost.

[0055] The tubular structure 104 may include a base 106 and a wrap 108. The base 106 may have a first surface 110 and a second surface 112 opposed to one another, where the distance between the first surface 110 and the second surface 112 defines a thickness of the base 106. The first surface 110 of the base 106 may define an elongated cavity 114, where the base 106 may have a tubular shape defining a longitudinal axis "L" extending along the elongated cavity 114. The wrap 108 may include a plurality of layers 116a, b, c, d (collectively referred to as the plurality of layers 116a, b, c, d, and individually referred to as the first layer 116a, the second layer 116b, the third layer 116c, and the fourth layer 116d), where the wrap 108 may be supported on the second surface 112 of the base 106. That is, as described in more detail below, a first layer 116a can be supported on the second surface 112 of the base 106, a second layer 116b can be supported on the first layer 116a, a third layer 116c can be supported on the second layer 116b, and a fourth layer 116d can be supported on the third layer 116c. While the tubular structure 104 is described below as including multiple layers 116a, b, c, d, it should be recognized that this is for the sake of clear and efficient description of the particular embodiment associated with the wrap 108 including multiple layers. However, it should be understood that any description below related to multiple layers 116a, b, c, d is applicable to implementations including only one instance of a layer and / or to implementations including more than four layers, unless otherwise specified. Additionally or alternatively, for purposes of clear and efficient description, each of the multiple layers 116a, b, c, d should be understood to have the same nominal composition as each other, and may have any one or more different nominal thicknesses that vary relative to each other as may be useful to achieve a given thickness profile (shape) of the tubular structure 104 in a direction parallel to the longitudinal axis "L".

[0056] With the wrap 108 supported on the base 106, the tubular structure 104 may have a strength similar to an otherwise identically sized structure formed using a thicker material with the same material thickness as the combined material thickness of the layers 116a,b,c,d and the base 106. However, compared to working with a thicker material to achieve a target thickness profile (e.g., strength profile) in the longitudinal direction, the wrap 108 supported on the base 106 provides significant advantages. For example, because each of the layers 116a,b,c,d is individually thinner than the thicker material, each of the layers 116a,b,c,d may be rolled, welded, or otherwise processed relatively easily compared to a thicker material. That is, compared to achieving a target total thickness using a wrap 108 disposed on the base 106, achieving a target total thickness may reduce manufacturing time and / or manufacturing costs. Similarly, each of the multiple layers 116a, b, c, d can be sized to reduce or eliminate the need for specialized equipment that may be required to handle thick material of thickness comparable to the multiple layers 116a, b, c, d.

[0057] In general, the base 106 can be any one or more of a variety of different tubular shapes useful for supporting the multiple layers 116a, b, c, d such that the combined tubular structure 104 can have a predetermined thickness profile in a direction parallel to the longitudinal axis "L". For example, the base 106 can include a frustoconical shape, which itself has a strength profile that makes efficient use of material to support the wind turbine 102, around which the wrap 108 is disposed to reinforce the wider end of the frustoconical shape (and thus add strength differential achievable between the wider end of the frustoconical shape and the narrower end of the frustoconical shape of a given dimension). Stated differently, the wrap 108 supported on the base 106 can advantageously isolate certain design constraints (e.g., strength vs. size) associated with forming a support structure using only a single layer of material.

[0058] In certain implementations, the base 106 can have a substantially constant thickness in a direction parallel to the longitudinal axis "L" (e.g., allowing for nominal manufacturing tolerances associated with commercially available sheet metal stock). Such a substantially constant thickness can be useful, for example, to form the base 106 using any one or more of a variety of different stock materials that can be easily and cost-effectively sourced. Additionally or alternatively, forming the base 106 with a constant thickness can be useful to rapidly form the base 106 using any one or more of a variety of different techniques and with little or no need for specialized equipment.

[0059] In general, the layers 116a,b,c,d of the wrap 108 may be dimensioned relative to each other and relative to the base 106 to achieve a predetermined thickness profile of the tubular structure 104 in a direction parallel to the longitudinal axis "L". Of note, one or more of the layers 116a,b,c,d may extend along only a portion of the longitudinal dimension of the base 106 such that the thickness of the wrap 108 in the radial direction varies in a direction parallel to the longitudinal axis "L" to facilitate modifying the thickness profile of the tubular structure 104 in a direction parallel to the longitudinal axis "L". For example, the number of layers 116a,b,c,d may decrease in a direction parallel to the longitudinal axis "L" such that the wrap 108 has a monotonically decreasing thickness in a direction parallel to the longitudinal axis "L". That is, according to this example, the tubular structure 104 may have a first overall thickness t along the first end portion 117. 1 , a second overall thickness t along the second end portion 119 2 In this case, the first total thickness t 1 is the second total thickness t 2It should be appreciated that one or more of the plurality of layers 116a,b,c,d can have a constant wall thickness in a direction parallel to the axis "L", while one or more of the plurality of layers 116a,b,c,d can have a wall thickness that varies at least along a portion of the longitudinal dimension of a given layer. Additionally or alternatively, each of the plurality of layers 116a,b,c,d can have the same thickness profile as one another, while one or more of the plurality of layers 116a,b,c,d can have a different thickness profile than at least one other of the plurality of layers 116a,b,c,d. Thus, more generally, unless otherwise specified or clear from the context, the plurality of layers 116a,b,c,d can have any one or more various different thickness profiles in a direction parallel to the longitudinal axis "L", as may be necessary or useful to achieve an overall thickness profile of the wrap 108 in a direction parallel to the longitudinal axis "L".

[0060] In the particular example shown in FIG. 1C , the multiple layers 116 a, b, c, d of the wrap 108 are supported on the base 106 in a wrapped configuration in which the multiple layers 116 a, b, c, d of the wrap are at least partially stacked on top of one another in a radial direction, resulting in a thickness profile of the tubular structure 104 having five distinct thicknesses in a direction parallel to the longitudinal axis “L”, in this case a first thickness t along a first end portion 117 of the tubular structure 104. 1 corresponds to the combined thickness of the base 106 and all of the layers 116a, b, c, d, while the second thickness t along the second end portion 119 of the tubular structure 104 2 corresponds to the wall thickness between the first surface 110 and the second surface 112 of the base 106.

[0061] Each of the multiple layers 116a,b,c,d can have a first longitudinal edge 113 and a second longitudinal edge 115 that are joined to one another such that each of the multiple layers 116a,b,c,d at least once circumscribes the base 106. For example, the first longitudinal edge 113 and the second longitudinal edge 115 of each of the multiple layers 116a,b,c,d can be joined to one another along a plurality of individual spiral seams 118a,b,c,d (collectively referred to as the plurality of spiral seams 118a,b,c,d, and individually referred to as the first spiral seam 118a, the second spiral seam 118b, the third spiral seam 118c, and the fourth spiral seam 118d). That is, the first layer 116a can form a first spiral seam 118a, the second layer 116b can form a second spiral seam 118b, the third layer 116c can form a third spiral seam 118c, and the fourth layer 116d can form a fourth spiral seam 118d. Each of the plurality of spiral seams 118a,b,c,d can extend about the longitudinal axis "L" of the base 106 such that each of the plurality of spiral seams 118a,b,c,d can be useful in forming each of the plurality of spiral seams 118a,b,c,d in a process of continuous or substantially continuous bonding (joining) as the base 106 rotates about the longitudinal axis "L" according to any one or more of a variety of different techniques described herein.

[0062] In certain implementations, the layers 116a,b,c,d may be joined to the base 106 and / or to one another in a manner useful for efficiently distributing external loads across the tubular structure 104, for example, the layers 116a,b,c,d may be joined to the base 106 and / or to one another with a plurality of welds 120a,b,c,d,e (collectively referred to as the plurality of welds 120a,b,c,d,e, and individually referred to herein as the first weld 120a, the second weld 120b, the third weld 120c, the fourth weld 120d, and the fifth weld 120e). As used in this context, the term "weld" should be understood to mean a joint formed between at least two adjacent portions of material.

[0063] For example, the first weld 120a can be a double-sided weld used to join the base 106 to itself along a seam 122 so that the base 106 can be a stable structure around which multiple layers 116a,b,c,d of the wrap 108 can be arranged and the multiple layers 116a,b,c,d can be secured directly or indirectly to form the tubular structure 104. In some cases, the seam 122 of the base 106 can be a spiral seam, which can be useful for fabricating the base 106 using any one or more of a variety of different automated techniques, such as those described in U.S. Patent No. 9,302,303, entitled "TAPERED STRUCTURE CONSTRUCTION," issued to Smith et al. on April 5, 2016, the entire contents of which are incorporated herein by reference. Additionally or alternatively, the first weld 120a may be formed as part of a process different than the process used to secure the multiple layers 116a,b,c,d to the base 106. Thus, the first weld 120a may correspond to a spiral seam in the base 106, although it should be recognized that such a spiral seam may not necessarily be used in the base 106, given that the base 106 may not be formed as part of a continuous or substantially continuous process in which a spiral seam would be useful. Additionally or alternatively, the second weld 120b may extend into the base 106 and into the first spiral seam 118a formed by the first longitudinal edge 113 and the second longitudinal edge 115 of the first layer 116a, such that the second weld 120b may be substantially coextensive with the first spiral seam 118a. Similarly, the third weld 120c can be coextensive along the second spiral seam 118b to join the first layer 116a and the second layer 116b to one another. In a similar manner, the second layer 116b, the third layer 116c, and the fourth layer 116d can be joined to one another via a fourth weld 120d and a fifth weld 120e.

[0064] Each of the first and second longitudinal edges 113, 115 of each of the multiple layers 116a,b,c,d includes one or more features that are useful for facilitating alignment and / or bonding of the edges to one another. For example, each of the first and second longitudinal edges 113, 115 may include a single bevel such that, upon alignment of the first and second longitudinal edges 113, 115 of a given layer, they form a "V" shape in which the second weld 120b, the third weld 120c, the fourth weld 120d, or the fifth weld 120e, respectively, may be formed using a single-sided welding process. In the first layer 116a, the provision of such a "V" edge may, for example, facilitate simultaneous joining of the first and second longitudinal edges 113, 115 to one another and to the base 106, resulting in better weld quality. Similarly, for each of the subsequent layers (second layer 116b, third layer 116c and fourth layer 116d), the preparation of the "V" edge can facilitate simultaneously joining the first longitudinal edge 113 and the second longitudinal edge 115 to each other and to the preceding layer, with a corresponding improvement in weld quality.

[0065] In some cases, the plurality of helical seams 118a,b,c,d may be longitudinally offset from one another in a direction parallel to the longitudinal axis "L" of the base 106. With such offset, the plurality of seams 118a,b,c,d do not line up on top of one another in a radial direction extending from the longitudinal axis "L". This type of spacing can facilitate distributing welding stresses along the tubular structure 104 as it is being formed, which in turn facilitates quality control of the tubular structure 104.

[0066] 2A and 2B, the system 230 can include one or more instances of a drive system 232, a bending device 234, a plurality of support rollers 236, and a pressure roll 238. Unless otherwise specified or clear from the context, the system 230 can be operable to form the tubular structure 104 (FIGS. 1A-1D). For example, the drive system 232 can be operable to move a feed material 239 in a planar form (e.g., from a feed material source 240) in a feed direction "F" to the bending device 234, where the feed material 239 in a planar form can be pre-bent into a curved form of the feed material 239. The curved form of the feed material 239 can be moved between one or more instances of a pressure roll 238 and a curved surface 241 of the material supported on the plurality of support rollers 236 to ultimately form the wrap 108 (FIGS. 1A-1D) of the tubular structure 104 (FIGS. 1A-1D). That is, depending on the stage of manufacture and thickness profile of the tubular structure 104 (FIGS. 1A-1D) being formed using the system 230, the curved surface 241 that receives the curved configuration of the feedstock 239 can be the second surface 112 of the base 106 (FIGS. 1A-1D) or a surface of a previous layer of the wrap 108 (FIGS. 1A-1D). Pre-rolling the feedstock 239 with the bending device 234 to form the curved configuration of the feedstock 239 can increase the degree to which the feedstock 239 conforms to the curved surface 241 (e.g., to the base 106 in FIGS. 1A-1D and / or to a previous layer of the plurality of layers 116a, b, c, d), thereby increasing the strength, stiffness, and / or other desired properties of the tubular structure being formed (e.g., the tubular structure 104 of FIGS. 1A-1D).

[0067] Generally, the drive system 232 can include a drive roll 233 operable to move the planar form of the stock material 239 in a feed direction "F". For example, the drive roll 233 can pinch the planar form of the stock material 239 such that rotation of the drive roll 233 can move the planar form of the stock material 239 along the feed direction "F". In certain implementations, the feed direction "F" can be substantially invariant (constant) (e.g., with the drive roll 233 in a substantially stationary position as rotation of the drive roll 233 moves the planar form of the stock material 239 to and / or through the bending device 234). Additionally or alternatively, the feed direction "F" can be varied such that the planar form of the stock material 239 undergoes rotational and / or substantial rotational motion as it moves to and / or through the bending device 234. Such changes in feed direction "F" can be useful for aligning edges of the blank material 239 to form any one or more of the helical seams described herein. Examples of such changes in feed direction "F" to produce rotational and / or substantially rotational motion as part of the tubular structure manufacturing process are described in U.S. Pat. No. 9,302,303, issued April 5, 2016 to Smith et al., entitled "TAPERED STRUCTURE CONSTRUCTION," and U.S. Pat. No. 10,189,064, issued January 29, 2019 to Takata et al., entitled "CONTROL SYSTEM AND METHOD FOR TAPERED STRUCTURE CONSTRUCTION," the entire contents of each of which are incorporated herein by reference. More specifically, the blank material 239 in planar form can be moved from the blank material source 240 to, and potentially through, the bending apparatus 234 using any equipment suitable for moving planar materials according to any of a variety of different techniques known in the art. Such equipment can include, for example, a robotic arm, a piston, a servo motor, a screw, an actuator, a roller, a driver, an electromagnet, or a combination thereof.

[0068] The bending device 234 can be positioned to receive the blank material in a planar form 239 moving in a feed direction "F", and the bending device 234 can bend the blank material in a planar form 239 fed thereto to produce the blank material in a curved form 239. As an example, the bending device 234 can bend the blank material in a planar form 239 without imparting an in-plane deformation to the blank material 239. Additionally or alternatively, the bending device 234 can impart a controlled amount of curvature to the blank material 239 such that the blank material in the curved form 239 can approximately match the curvature of the curved surface 241 along which it moves.

[0069] The bending device 234 can include, for example, roll rows 242a, 242b, 242c that are positioned relative to each other and to the planar form of the stock material 239 to impart a curvature to the planar form of the stock material 239 fed through the roll rows 242a, 242b, 242c. In some cases, the roll rows 242a, 242b, 242c can be configured as three rolls, and additionally or alternatively, the roll rows 242a, 242b, 242c can be movable relative to each other to change the bending moment applied to the stock material 239 passing through the bending device 234. Each of the roll rows 242a, 242b, 242c can include, for example, multiple individual rollers that are independently rotatable relative to each other and aligned along respective axes defined by each of the roll rows 242a, 242b, 242c. Additionally or alternatively, the individual rollers of roll rows 242a, 242b, 242c can be positionable (e.g., via actuation signals received by a control system) relative to individual axes defined by each of roll rows 242a, 242b, 242c.

[0070] In general, the support rollers 236 can allow the curved surface 241 of the tubular structure being formed to rotate relative to the curved form of the stock material 239 moving from the bending device 234 onto the curved surface 241. In some implementations, the support roller(s) 236 can be actively controlled to rotate the curved surface 241 at a predetermined speed, which can be useful to provide tension to the curved form of the stock material 239 to facilitate intimate placement of the curved form of the stock material 239 onto the curved surface 241. In some cases, the support roller(s) 236 can be passive, allowing the force of the curved form of the stock material 239 moving onto the curved surface 241 to rotate the curved surface 241 as the tubular structure is being formed.

[0071] Each of the one or more instances of the pressure roll 238 may include one or more rollers movable to press the curved form of the stock material 239 onto a curved surface 241 rotatably supported on the plurality of support rollers 236. For example, at least one instance of the pressure roll 238 may be rotatable about an axis parallel to the curved surface 241 of the base 106 to move the curved form of the stock material 239 from the bending device 234 onto the curved surface 241. Additionally or alternatively, at least one instance of the pressure roll 238 may be movable radially relative to the tubular structure being formed, where such radial movement of the at least one instance of the pressure roll 238 is useful for controlling the degree of conformity between the curved form of the stock material 239 and the curved surface 241. Stated another way, the radial movement of at least one instance of pressure roll 238 can reduce the likelihood of unintended gaps between layers of material of the wrap and / or between the wrap and the base, where the reduced likelihood of such gaps includes improved load-bearing capabilities.

[0072] In certain implementations, the system 230 can include a bonding device 244 positioned or positionable to bond (e.g., mechanically bond) the curved form of the stock material 239 to itself (e.g., along any one or more of the helical seams described above with respect to FIGS. 1A-1D). Additionally or alternatively, the bonding device 244 can be positioned or positionable to bond the curved form of the stock material 239 to a curved surface 241 rotatably supported on a plurality of support rollers 236. As an example, the bonding device 244 can be positioned between two instances of the pressure roll 238 to increase the likelihood of a tight fit between the curved form of the stock material 239 and the curved surface 241 as the bonding operation occurs. In some cases, the bonding device 244 can mechanically bond the materials together continuously as the curved form of the stock material 239 moves onto the rotating curved surface 241 on the support rollers 236. Such continuous mechanical bonding can be useful, among other things, to achieve a target structural strength of the tubular structure being formed. Additionally or alternatively, the bonding device 244 can be operable to intermittently bond (e.g., at a distance) the material along any one or more of a variety of different helical seams described herein, where such intermittent bonding is useful for faster throughput.

[0073] The joining device 244 may include, for example, a welder operable to form any one or more of the various different welds described herein. A wide variety of techniques for welding are known in the art and may be adapted to join any one or more edges together as contemplated herein. This may include, for example, any welding technique that melts a base metal or other material, optionally with a filler added to the joint to improve the strength of the bond, along any one or more of the various different seams described herein. Conventional welding techniques suitable for structurally joining metals include, by way of example and without limitation, gas metal arc welding (GMAW), including inert gas (MIG) and / or metal active gas (MAG); submerged arc welding (SAW); laser welding; and gas tungsten arc welding (also known as tungsten inert gas welding or "TIG" welding); and many others.

[0074] In a particular embodiment, the system 230 can include a guide system 245 arranged to receive the curved form of the stock material 239 from the bending device 234. The guide system 245 can include an actuator 246 that can be controlled to wrap the curved form of the stock material 239 (e.g., in a direction substantially parallel to the longitudinal axis of the tubular structure being formed) along an individual helical seam of a given layer of wrap that is bonded to a base of the tubular structure being formed, for example. Some examples of the actuator 246 include, but are not limited to, one or more edge guides, one or more edge rollers, one or more pinch rollers, or combinations thereof. In some cases, the guide system 245 can further include a sensor 247 operable to detect a parameter indicative of a position of the curved form of the stock material 239 along the helical seam formed by the curved form of the stock material 239 moving onto the curved surface 241. Examples of the sensor 247 can include an optical sensor, one or more cameras of a machine vision system, a contact sensor, or combinations thereof. The actuator 246 can be adjustable based on a signal from the sensor 247, for example, to effect a corresponding adjustment of the position of the curved form of the blank 239 along the spiral seam being formed as the curved form of the blank 239 moves onto the curved surface 241.

[0075] While one or more aspects of the operation of the system 230 may be performed through manual operation by an operator, in some implementations the system 230 may include a control system 248 to facilitate precise and repeatable control of certain aspects of the operation of the system 230. The control system 248 may include, for example, a processing unit 249 and a storage medium 250 in communication with the processing unit 249. The processing unit 249 may include one or more processors, and the storage medium 250 may include a non-transitory computer-readable storage medium. The storage medium 250 may store computer-executable instructions that, when executed by the processing unit 249, cause the system 230 to perform one or more various different aspects of manufacturing tubular structures using the system 230. Optionally, control system 248 may include input devices (e.g., a keyboard, mouse, and / or graphical user interface) in communication with processing unit 249 and storage medium 250 such that processing unit 249 is additionally or alternatively responsive to input received via such input devices as processing unit 249 performs one or more manufacturing methods described herein.

[0076] 3 is a flow diagram of an exemplary method 352 for forming a tubular structure. Unless otherwise specified or clear from the context, any one or more aspects of the exemplary method 352 may be embodied as computer readable instructions stored in a storage medium 250 (FIG. 2A) and executable by a processing unit 249 (FIG. 2A) of a control system 248 (FIG. 2A) to operate a system 230 (FIG. 2A) to form a tubular structure 104 as described in connection with FIGS. 1A-1D. In certain implementations, the exemplary method 352 may include certain preparatory steps, which may include joining multiple sheets together in a nonlinear butt engagement with each other to produce a blank in a planar form having straight longitudinal edges that can be wrapped to form a helical seam. Additionally or alternatively, the exemplary method 352 may include fastening the blank to a curved surface of a base or to a previous layer, possibly at the beginning of the process of winding a given layer. For clarity and efficiency of explanation, these preparatory steps are described in detail below in connection with the description of Figure 5, with the assumption that such steps are more readily understood in connection with the diagrams of the hardware in Figures 4A and 4B used to perform the method depicted in Figure 5. However, unless otherwise indicated or apparent from the context, it should be understood that any one or more of the preparatory steps described below in connection with Figure 5 could be included in the example method 352 without departing from the scope of the present disclosure.

[0077] As shown at step 354, the exemplary method 352 can include bending a portion of the strip of blank material in a planar configuration into a curved configuration. Such bending can be performed, for example, by moving the blank material in a planar configuration into and through a bending device, such as bending device 234 (FIGS. 2A and 2B). Through such bending, the blank material can approximate the curvature of a curved surface through which the blank material may be guided. For example, in an example where the tubular structure being formed is frustoconical, the strip of blank material in a planar configuration can be bent into gradually varying dimensions in accordance with corresponding changes in dimensions of the frustoconical shape of the tubular structure being formed. In this regard, it should be recognized that although the multiple layers wrapped around the frustoconical base may deviate from the geometric frustoconical shape, the resulting shape of the tubular structure having these features is nevertheless referred to herein as frustoconical.

[0078] As shown at step 356, the exemplary method 352 can include wrapping a curved form of a feedstock material onto a curved surface of a base (e.g., base 106 of FIGS. 1B and 1C) to form a helical seam about a longitudinal axis defined by the base. The base can be formed separately (e.g., via a can-rolling process or a helical welding process) or can additionally or alternatively be a single layer of material (e.g., having a constant thickness) having a tubular shape. In general, wrapping a curved form of a feedstock material onto a curved surface of the base can include any method and form of physical positioning of the curved form of the feedstock material to conform the substrate material onto the curved surface while also positioning the feedstock material against itself (e.g., two longitudinal edges) to form a helical seam that extends about the longitudinal axis of the base. Thus, for example, wrapping a curved form of the feedstock material onto a curved surface can include moving the feedstock material in a curved form using any one or more of a variety of different guiding systems described herein. Additionally or alternatively, wrapping a curved form of the feedstock material onto a curved surface can include forcing the feedstock material onto the curved surface with pressure applied by one or more pressure rolls described herein.

[0079] As shown at step 358, the exemplary method 300 can include joining (bonding) the feedstock material in a curved form to at least itself along the helical seam. Additionally or alternatively, the feedstock material can be joined to the curved surface of the base along the helical seam. Unless otherwise specified or apparent from the context, joining the feedstock material in a curved form to itself along the helical seam can include any one or more of a variety of different welding techniques described herein. As a specific example, joining the feedstock material in a curved form to itself can include welding the feedstock material in a curved form to itself and to the curved surface of the base along the helical seam. In some cases, the welding process can include inspection, such as visual, ultrasonic, magnetic particle, or other techniques, performed manually or automatically after one layer is added and before the next layer is added to hide or otherwise obscure inspection of the weld. Additionally or alternatively, the weld cap may be removed (e.g., by grinding away the cap material until the weld is flush with the surface of the layer to which it is welded) using any one or more of a variety of different manual and / or automated techniques before the next layer is added. For example, weld cap removal may be performed in-line with the weld and / or alternatively may be performed continuously as the tubular structure is being formed, reducing the time and cost required to remove the weld cap. Removing the weld cap may, in some cases, facilitate more closely conforming the subsequent layer to the base or to the previous layer, as compared to cases in which the weld cap is not removed.

[0080] Although the steps of the exemplary method 352 have been described in connection with securing a first layer of wrap onto a base, it should be appreciated that any one or more of the various different steps of the exemplary method 352 may be repeated as necessary to add additional layers of wrap to the base. However, it should be appreciated that by repeating the steps to place a layer after the first layer, each subsequent layer may be wrapped over the previous layer in the stack of layers, and each layer may form a spiral seam that is different from the spiral seam formed by the previous layer.

[0081] Having described certain systems and methods for forming a tubular structure 104 (FIGS. 1A-1D) based on a layer of wrap that is pre-bent prior to placement onto a base, and methods for operating such systems, attention is now turned to describing a system and method for forming a tubular structure 104 (FIGS. 1A-1D) using tension to conform a curved form of blank material onto a curved surface.

[0082] 4A and 4B, system 460 can include one or more instances of tension roller 462, rotator 464, guide system 466, and bonding device 468. Each instance of tension roller 462 can be positionable in contact with the planar form of stock material 469 as it moves in feed direction "F" to apply tension to the planar form of stock material 469. Rotator 464 can be operable to rotate a curved surface, such as second surface 112, of base 106 about longitudinal axis "L". The feedstock material 469 may be directly or indirectly attached to the curved surface of the base 106 such that as the rotator 464 rotates the curved surface of the base 106 away from one or more instances of the tension roller 462, the rotation of the base 106 may pull the feedstock material 469 in the planar form from the feedstock source 470 towards the base 106 in the feed direction "F." As the curved surface of the base 106 continues to rotate, the feedstock material 469 in the planar form may be pulled onto the curved surface of the base 106, bending the feedstock material 469 along the first spiral seam 118a to form the first layer 116a.

[0083] Precise positioning of the feedstock material 469 along the first spiral seam 118a to form the first layer 116a (and position along the associated spiral seam with subsequent layers) may be advantageously achieved through a combination of the shape of the feedstock material 469 in planar form and the operation of the guide system 466. That is, the feedstock material 469 in planar form from the feedstock source 470 may include multiple sheets in non-linear butt engagement with one another according to any one or more of a variety of different techniques. In particular, unless otherwise specified or clear from the context, the planar form of the stock material 469 and any other stock material (e.g., stock material 239 of FIG. 2B) described herein can include multiple sheets in non-linear butt engagement with one another according to techniques for arranging linearly edged sheets of material relative to one another to form a spiral seam, as described in U.S. Patent No. 9,302,303, entitled “TAPERED STRUCTURE CONSTRUCTION,” issued to Smith et al. on April 5, 2016, the entire contents of which are incorporated herein by reference. Additionally, between one or more instances of tension roller 462 and base 106, guide system 466 can adjust the position of stock material 469 such that stock material 469 is wrapped along first spiral seam 118a.

[0084] It should be appreciated that following the rotation of the curved surface of the base 106 to form the first layer 116a, a similar rotation of the curved surface of the base 106 about the longitudinal axis "L" can form subsequent layers by pulling the flat form of the blank material 469 onto the first layer 116a. This process can be repeated as necessary to form wraps including a predetermined number and location of layers to achieve a thickness profile according to design specifications. In particular, the resulting tight fit by pulling the flat form of the blank material 469 onto the curved surface of the base 106 or onto a previous layer of material can be useful to improve the structural quality of the tubular structure being formed.

[0085] In general, one or more instances of tension roller 462 may be operable to move perpendicular to a major surface of planar feedstock 469 to increase or decrease tension in planar feedstock 469, which may be useful for controlling positioning of feedstock 469 along the helical seam. Additionally or alternatively, tension in planar feedstock 469 moving in feed direction "F" may be adjusted by controlling resistance to rotation of tension roller 462. One or more instances of tension roller 462 may define a gap through which planar feedstock 469 may pass, and the position of one or more instances of tension roller 462 may be controllable to move the gap in a direction perpendicular to feed direction "F". Additionally or alternatively, each instance of tension roller 462 may be rotatable about an axis perpendicular to at least feed direction "F".

[0086] The rotator 464 may include, for example, one or more rollers drivable to rotate the base 106 about the longitudinal axis "L" at a controlled speed. Additionally or alternatively, at least a portion of the rotator 464 may support the base 106 as it rotates to wrap the blank material 469 along the spiral seam. For example, the rotator 464 may support at least each end of the base 106.

[0087] The guide system 466 can include an actuator 471 that is controllable to wrap the flat form of the feedstock 469 along a spiral seam extending about the longitudinal axis "L" of the base 106. The actuator 471 can control the position of the flat form of the feedstock 469 in a direction perpendicular to the feed direction "F", which can be useful, for example, to effect fine adjustment of the feedstock 469 to position longitudinal edges of the feedstock 469 adjacent to one another to form the spiral seam as the feedstock 469 is wrapped onto the base 106 through rotation of the base 106. The actuator 471 can include, for example, one or more edge guides, one or more edge rollers, one or more pinch rollers, or a combination thereof.

[0088] Additionally or alternatively, the guidance system 466 can include a sensor 472 operable to detect a parameter indicative of a position of the feedstock 469 in planar form. The actuator 471 can be adjustable based on a signal from the sensor 472 to adjust the position of the feedstock 469 in planar form as the tubular structure is being formed. For example, the sensor 472 can detect the position of the feedstock 469 in planar form at a position just before the feedstock 469 is wrapped along the helical seam. Additionally or alternatively, the sensor 472 can detect the position of the feedstock 469 along the helical seam being formed by the feedstock 469 (e.g., a longitudinal edge of the feedstock 469). The sensor 472 can include, for example, an optical sensor, a camera as part of a machine vision system, a contact sensor, or a combination thereof.

[0089] In general, the bonding device 468 can mechanically bond the blank material 469 to itself and / or to the base 106 according to any one or more of a variety of different techniques described herein. Thus, the bonding device 468 can include a welder operable to form any one or more of a variety of different welds described herein. For example, in connection with fastening the blank material 469 to the base 106, the bonding device 468 can form the weld 120b (FIG. 1D). It should be appreciated that the bonding device 468 can similarly form other welds associated with the addition of subsequent layers as necessary to form a wrap on the base 106 to achieve a tubular structure having a predetermined strength profile.

[0090] While one or more aspects of the operation of the system 460 may be performed through manual operation by an operator, in some implementations the system 460 may include a control system 473 to facilitate precise and repeatable control of certain aspects of the operation of the system 460. The control system 473 may include, for example, a processing unit 474 and a storage medium 475 in communication with the processing unit 474. The processing unit 474 may include one or more processors, and the storage medium 475 may include a non-transitory computer-readable storage medium. The storage medium 475 may store computer-executable instructions that, when executed by the processing unit 474, cause the system 460 to perform one or more various different aspects of manufacturing tubular structures using the system 460. Optionally, control system 473 may include input devices (e.g., a keyboard, mouse, and / or graphical user interface) in communication with processing unit 474 and storage medium 475 such that processing unit 474 is additionally or alternatively responsive to input received via such input devices as processing unit 474 performs one or more manufacturing methods described herein.

[0091] 5 is a flow diagram of an exemplary method 576 of forming a tubular structure. Unless otherwise specified or apparent from the context, any one or more aspects of the exemplary method 576 may be embodied as computer-readable instructions stored on a storage medium 475 (FIG. 4A) and executable by a processing unit 474 (FIG. 4A) of a control system 473 (FIG. 4A) to operate a system 460 (FIG. 4A) to form a tubular structure 104 as described in connection with FIGS. 1A-1D.

[0092] As shown at step 577, the exemplary method 576 can include joining (e.g., welding) a plurality of plates (e.g., trapezoidal shaped metal plates) in butt engagement with one another to produce a blank material in a planar form. In this regard, butt joining should be understood to include joining a short edge of one plate together with a short edge of another plate to form a seam perpendicular to the parallel long edges of each plate. Such joining can include, for example, welding the plates together according to any one or more of a variety of different welding techniques described herein. As discussed above, the nonlinear butt engagement of the plurality of plates can include a geometry in which straight edges (e.g., parallel straight edges) can be bent to form a helical seam. In certain implementations, the plurality of plates can be joined in nonlinear butt engagement with one another such that a longitudinal edge of each plate is perpendicular to a longitudinal edge of at least one other plate. Additionally or alternatively, multiple plates may be joined in linear butt engagement with one another such that the longitudinal edges of each plate are collinear with the respective longitudinal edges of the other plates. Additionally or alternatively, in instances where the tubular structure being formed is a right circular cylinder, a single plate may be used as the blank for the planar form.

[0093] As shown at step 578, the exemplary method 576 can include securing the feedstock material to the curved surface of the base that defines the longitudinal axis. As tension is applied to the feedstock material, it may generally be desirable to use one or more techniques to permanently secure the feedstock material to the curved surface to reduce the likelihood of the feedstock material unintentionally detaching from the curved surface. For example, the feedstock material can be secured to the curved surface of the base using one or more welding techniques described herein.

[0094] As shown at step 579, the exemplary method 576 can include rotating the curved surface of the base about a longitudinal axis of the base. With respect to the stock material secured to the base (e.g., secured directly or indirectly to the curved surface of the base), it should be recognized that rotating the curved surface of the base can bend the stock material in a planar configuration about the curved surface of the base. That is, the stock material can be bent about the curved surface of the base such that the stock material and the base collectively form at least a portion of the tubular structure being formed. For a first layer, the stock material in a planar configuration that bends about the curved surface of the base can conform the stock material directly onto the curved surface of the base. Additionally or alternatively, with respect to a subsequent layer, the stock material in a planar configuration that bends about the curved surface of the base can conform the stock material directly onto the previous layer of stock material secured to the base. In certain implementations, by controlling the position of the blank as it is bent around the curved surface of the base, the first longitudinal edge and the second longitudinal edge of the blank can form a helical seam about the longitudinal axis of the base such that the blank and the base collectively define at least a portion of the tubular structure being formed.

[0095] As shown at step 580, an example method 576 can include moving the feedstock material in the planar form, with the feedstock material secured to the base, through one or more tension rollers as the curved surface of the base rotates about its longitudinal axis. The one or more tension rollers can be adjustable to adjust the amount of tension in the feedstock material in the planar form, for example, to facilitate achieving a tight fit of the feedstock material moving over the curved surface of the base.

[0096] As shown at step 581, the example method 576 can include joining the feedstock material to itself along the at least one spiral seam. For example, joining the feedstock material to itself along the at least one spiral seam can include welding the feedstock material to itself to form a weld coextensive with the spiral seam. Additionally or alternatively, joining the feedstock material to itself along the at least one spiral seam can include joining the feedstock material to a curved surface of the base, to a previous layer of the feedstock material, or a combination thereof.

[0097] In general, unless otherwise specified or apparent from the context, it should be recognized that any one or more of the various different steps of the exemplary method 576 may be repeated as necessary to wrap multiple layers over each other in any number and geometric arrangement of layers useful for forming a tubular structure having a predetermined strength profile.

[0098] Although particular implementations have been described, other implementations are additionally or alternatively possible.

[0099] For example, although a flat form of stock material has been described as being wrapped onto a base to form a tubular structure, it should be recognized that the flat form of stock material can also or alternatively be wrapped onto a reusable mandrel in place of the base to form part of the final tubular structure. Continuing with this example, the process of adding material can be repeated using the first layer (formed on the mandrel) as a base until a tubular structure is formed, with the number and arrangement of layers including wraps as needed to achieve a predetermined strength profile for the tubular structure.

[0100] As another example, while the reinforced tubular structure has been described as including a base and one or more layers wrapped around the base to provide increased thickness (and therefore strength) to the base, other approaches to the reinforced tubular structure are additionally or alternatively possible. For example, as described in the examples below, the tubular structure can include stabilizers disposed between multiple shells to provide overall strength to the tubular structure.

[0101] 6A and 6B, the tubular structure 682 can include a first shell 683, a second shell 684, and a filler material 685. The second shell 684 can have a frustoconical shape, and the first shell 683 can be nested within the second shell 684 such that the first shell 683 and the second shell 684 define a gap therebetween. The filler material 685 can be disposed within the gap defined between the first shell 683 and the second shell 684. For example, the filler material 685 can fill the gap, which can be useful for achieving uniform strength characteristics in the tubular structure 682. In particular, the filler material 685 can facilitate the transfer of stress (e.g., shear stress) between the first shell 683 and the second shell 684. Additionally or alternatively, the filler material 685 disposed in the gap defined by the first shell 683 and the second shell 684 can reduce the likelihood of the first shell 683 and the second shell 684 bending under a given load compared to the likelihood of the first shell 683 and the second shell 684 bending under the same load without the filler material 685 between the first shell 683 and the second shell 684. That is, the tubular structure 682 can achieve strength and stiffness comparable to that of a tubular structure formed with thick, solid metal walls. However, the first shell 683 and the second shell 684 can have thinner metal walls compared to a tubular structure formed with thick, solid metal walls, and the strength performance of the tubular structure 682 can generally be achieved at a significantly lower cost and in a significantly faster production time compared to forming a tubular structure that achieves the same strength performance using thick, solid metal walls.

[0102] In general, one or both of the first shell 683 or the second shell 684 may be formed using spiral forming of a strip of stock material. In some cases, the first shell 683 and the second shell 684 may be concentrically aligned with one another such that a gap defined between the first shell 683 and the second shell 684 is substantially symmetrical about a central axis "C" defined by the first shell 683 and the second shell 684. Among other things, such symmetry may be useful to generally form the tubular structure 682 with substantially uniform strength circumferentially about the frustoconical shape of the second shell 684. In some cases, the second shell 684 may surround the first shell 683 such that the gap formed by the first shell 683 and the second shell 684 is annular, where such an annular shape is useful to contain the filler material 685 between the first shell 683 and the second shell 684 and away from the outside environment. As a more specific example, the first shell 683 can be substantially parallel to the second shell 684 along a longitudinal axis (e.g., central axis "C") defined by the first shell 683. That is, the first shell 683 can have a frustoconical shape that is parallel to the frustoconical shape of the second shell 684, such that the gap between the first shell 683 and the second shell 684 is also frustoconical. As with other frustoconical shapes described herein, the frustoconical shape of the gap between the first shell 683 and the second shell 684 can be useful for achieving strength performance using less material and, ultimately, at less cost.

[0103] The filler material 685 may include, for example, a material bonded to the first shell 683, the second shell 684, or a combination thereof. The filler material may include any one or more of a variety of different types of materials that can be bonded to metal while having the desired strength properties for a given end use application. As an example, the filler material may include a material that has consistent strength properties throughout the volume of the filler material. Some examples of materials useful for the filler material include cement, filled epoxy resin, grout, high density foam, sand, or combinations thereof. In some cases, the filler material may include multiple components that are spatially separated from each other in a longitudinal direction parallel to the central axis "C", with such spatial separation of the components useful for achieving a targeted strength profile. Continuing with this example, the components of such a filler material may include different concrete mixes arranged in layers in a direction parallel to the central axis "C".

[0104] 7A-7C, the tubular structure 787 can include a first shell 788, a second shell 789, and a plurality of structural elements 790 (e.g., steel bars, ribs, tubes, or combinations thereof). Unless otherwise specified or clear from the context, the first shell 788 and the second shell 789 can be arranged relative to one another in a manner similar to any one or more configurations of the first shell 683 and the second shell 684 described above in connection with FIGS. 6A-6B. Thus, for example, the second shell 789 can have a frustoconical shape, and the first shell 788 can be nested within the second shell 789 such that a gap 791 is defined between the first shell 788 and the second shell 789. A plurality of structural elements 790 can be coupled to each of the first shell 788 and the second shell 789 and extend through the gap 791. Through such bonding, each of the plurality of structural elements 790 can facilitate transferring shear loads and / or reducing the likelihood of bending of each shell. More specifically, with the plurality of structural elements 790 bonding the first shell 788 and the second shell 789, the tubular structure 787 can achieve structural performance similar to that of a tubular structure formed with thick, solid metal walls. Thus, as with other examples described herein, the annular structure 787 can facilitate achieving structural performance comparable to that of a tubular structure formed with thick, solid metal walls, while being significantly less costly to fabricate.

[0105] In some cases, the first shell 788 can define a plurality of first holes 792 and the second shell 789 can define a plurality of second holes 793 aligned with the plurality of first holes 792. Continuing with this example, each of the plurality of structural elements 790 can extend through one of the plurality of first holes 792 and a corresponding one of the plurality of second holes 793 such that it can be useful for installing the structural element 790 within the gap 791 and / or replacing a structural element within the gap 791 without requiring access to the gap 791. For example, each of the plurality of structural elements 790 can pass through the plurality of first holes 792 and into the plurality of second holes 793 to couple the first shell 788 and the second shell 789 to one another. Additionally or alternatively, each of the multiple structural elements 790 may be welded or otherwise joined to each of the first shell 788 and the second shell 789 to stiffen the tubular structure 787 compared to the stiffness of the first shell 788 and the second shell 789 alone.

[0106] While particular implementations of reinforced tubular structures have been described as including stabilizers disposed between the shells, it should be appreciated that stabilizers may also or alternatively be disposed along the exterior surfaces of the shells to form tubular structures that are cheaper and quicker to manufacture than tubular structures formed from thick, solid metal walls, while at the same time having structural performance comparable to that of tubular structures formed from thick, solid metal walls.

[0107] 8A-8C, for example, tubular structure 880 can include a shell 888 and a plurality of elongated ribs 889. Shell 888 can have opposing first and second surfaces 891 and 892, and first surface 891 can define a cavity 893. Shell 888 can have a tubular shape (e.g., a frusto-conical shape) defining a longitudinal axis "L." The shell 888 may have a spiral seam 894 extending about a longitudinal axis "L", and each of the plurality of elongated ribs 889 may be coupled to the shell 888 (e.g., along one or both of a first surface 891 or a second surface 892) with a longitudinal dimension of each elongated rib 889 being substantially coplanar with the longitudinal axis "L" such that the longitudinal dimension of each of the elongated ribs 889 extends across the spiral seam 894 of the shell 888 to provide structural support across the spiral seam 894. In certain implementations, each of the plurality of elongated ribs 889 may be notched to facilitate passage through the spiral seam 894 of the shell 888 underlying the plurality of elongated ribs 889 with reduced likelihood of interfering with a close fit between each of the plurality of elongated ribs 889 and the shell 888.

[0108] The elongated ribs 889 may be spaced relative to one another along the shell 888 according to any spacing that may be useful to achieve a target structural performance. For example, the elongated ribs 889 may be joined to one another along longitudinal seams 895 that are substantially coplanar with the longitudinal axis "L" defined by the tubular shape of the shell. As a more specific example, the elongated ribs 889 may be joined to one another around the shell 888, as may be useful to achieve a substantially uniform strength around the circumference of the shell 888. Although the elongated ribs 889 may be joined to the shell 888 using any one or more of a variety of different techniques, the longitudinal seams 895 may be formed in some implementations by welding the elongated ribs 889 to the shell 888 using a full weld or a skip weld.

[0109] In certain implementations, each of the elongated ribs 889 can be V-shaped with a first leg 896 and a second leg 897 joined to one another at an apex 898, where the first leg 896 and the second leg 897 are joined to the shell 888 such that the apex 898 faces radially away from the shell 888. Continuing with this example, the elongated ribs 889 can be formed into the V-shape using a press brake. Additionally or alternatively, the elongated ribs 889 can be roll formed or formed from a pair of flat strips of material that are joined (e.g., welded) together at the apex 898.

[0110] The above-mentioned systems, devices, methods, processes, etc. may be realized in hardware, software, or any combination thereof suitable for the control, data acquisition, and data processing described herein. This includes realization in one or more microprocessors, microcontrollers, embedded microcontrollers, programmable digital signal processors, or other programmable devices or processing circuits, along with internal and / or external memory. Also or alternatively, this may include one or more application specific integrated circuits, programmable gate arrays, programmable array logic components, or any other device(s) that may be configured to process electronic signals. As will be further appreciated, the realization of the above-mentioned processes or devices may include computer executable code created using one of the above-mentioned devices, as well as a structured programming language such as C, an object-oriented programming language such as C++, or any other high-level or low-level language (including assembly language, hardware description language, and database programming language and technology) that may be stored, compiled, or interpreted for execution in a heterogeneous combination of processors, processor architectures, or combinations of different hardware and software. At the same time, processing may be distributed across devices such as the various systems described above, or all of the functionality may be integrated into a dedicated stand-alone device, and all such permutations and combinations are intended to fall within the scope of the present disclosure.

[0111] The embodiments disclosed herein may include a computer program product including computer executable or computer usable code that, when executed on one or more computing devices, performs any and / or all steps of the control system described above. The code may be stored in a persistent manner in a computer memory, which may be the memory in which the program is executed (e.g., a random access memory associated with a processor) or a storage device such as a disk drive, flash memory, or any other optical, electromagnetic, magnetic, infrared, or other device or combination of devices. In another aspect, any of the control systems described above may be embodied in any suitable transmission or propagation medium that transmits the computer executable code, and / or any input or output from the transmission or propagation medium.

[0112] The steps of the methods of the embodiments described herein are intended to include any suitable manner of causing such method steps to be performed, consistent with the patentability of the claims that follow, unless a different meaning is expressly provided or apparent from the context. Thus, for example, performing step X includes any suitable manner of causing another party, such as a remote user, a remote processing resource (e.g., a server or cloud computer), or a machine to perform step X. Similarly, performing steps X, Y, and Z can include any manner of managing or controlling any combination of other individuals or resources involved in performing steps X, Y, and Z to obtain the benefit of such steps. Thus, the steps of the methods of the embodiments described herein are intended to include any suitable manner of causing one or more other parties or entities to perform such steps, consistent with the patentability of the claims that follow, unless a different meaning is expressly provided or apparent from the context. Such parties or entities need not be under the management or control of any other party or entity, and need not be located within any particular jurisdiction.

[0113] It is recognized that the above described method and system are described by way of example and not by way of limitation. Numerous variations, additions, omissions and other modifications will become apparent to those skilled in the art. Moreover, the order and presentation of the method steps in the above description and drawings is not intended to require this order of performing the recited steps unless a particular order is expressly required or becomes apparent from the context. Thus, while specific embodiments have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications in form and detail can be made without departing from the spirit and scope of the disclosure, which is intended to form part of the present invention, which should be interpreted in the broadest sense permitted by law.

Claims

1. A tubular structure for a wind turbine assembly, comprising: a base having a tubular shape with opposing first and second surfaces, the first surface defining an elongated cavity and a longitudinal axis extending along the elongated cavity; a wrap supported on the second surface of the base; A tubular structure, wherein the wrap includes a plurality of layers stacked on top of one another in a radial direction away from the longitudinal axis, each layer of the plurality of layers having a first longitudinal edge and a second longitudinal edge welded to one another along respective helical seams extending about the longitudinal axis of the base, a first layer of the plurality of layers being welded to the base along the respective helical seams of the first layer, and each subsequent layer of the plurality of layers in the radial direction being welded to a preceding layer of the plurality of layers along the respective helical seams of a given subsequent layer.

2. The tubular structure of claim 1 , wherein the combined thickness of the wrap and the base varies in a direction parallel to the longitudinal axis of the base.

3. 3. The tubular structure of claim 1 or 2, wherein the thickness of the wrap varies in a direction parallel to the longitudinal axis of the base.

4. The tubular structure according to any one of claims 1 to 3, wherein the thickness of the base is substantially constant in a direction parallel to the longitudinal axis of the base.

5. The tubular structure of any one of claims 1 to 4, wherein the thickness of the wrap varies monotonically in a direction parallel to the longitudinal axis of the base.

6. 6. The tubular structure of claim 1, wherein the tubular shape of the base comprises a frusto-conical shape tapering in a direction parallel to the longitudinal axis, and the thickness of the wrap decreases monotonically in the direction of the taper of the frusto-conical shape.

7. The tubular structure of claim 1 , wherein each layer of the plurality of layers encircles the base at least once.

8. The tubular structure of claim 1 , wherein a number of layers in the plurality of layers varies in a direction parallel to a longitudinal axis of the base.

9. 9. A tubular structure as claimed in any one of claims 1 to 8, wherein the individual spiral seams of a given layer are longitudinally offset from the individual spiral seams of each adjacent layer to the given layer.

10. A tubular structure according to any one of claims 1 to 9, wherein the base includes a seam extending about a longitudinal axis of the base.

11. 11. The tubular structure of claim 10, wherein the individual spiral seams of at least one layer of the wrap are longitudinally spaced from the base seam along the longitudinal axis.

12. 12. A tubular structure as claimed in claim 10 or 11, wherein the base seam is parallel to the individual helical seams of at least one layer of the wrap.

Images