Methods for joining structural elements

Abstract

The present invention provides a method and system for joining structural elements. [Solution] The means include arranging the end portions of each of the pair of structural elements so that they are opposite to each other, arranging at least one coupler so that it is positioned close to the end portions of each of the pair of structural elements, providing an inert atmosphere covering the coupler and the end portions of each of the pair of structural elements, heating the heated coupler section of the at least one coupler to the hot working temperature of the coupler, and causing the coupler and at least one or more of the pair of structural elements to undergo an engaging motion where they move relative to the other.

Description

[Technical Field]

[0001] Cross-reference of related applications This disclosure claims priority to U.S. Provisional Patent Applications No. 63 / 730,003 and No. 63 / 737,847, filed on 10 December 2024 and 23 December 2024, respectively, both of which are incorporated herein by reference.

[0002] This disclosure is generally directed toward metallurgy, and more specifically, toward methods for joining structural elements. [Background technology]

[0003] In prior art, structural elements, such as steel pipes, can be welded together using conventional welding methods. However, conventional welding methods have several drawbacks. They tend to be somewhat time-consuming, and there is a global shortage of qualified welders. Furthermore, conventional welding methods tend to produce inconsistent weld quality.

[0004] Conventional methods often result in welded products that include a zone containing molten and cooled metal. In this zone, the molten and cooled metal may have different characteristics from the surrounding material body, which can be undesirable.

[0005] Therefore, a novel method for joining structural elements is provided. [Overview of the Initiative]

[0006] For the reasons stated above, there is a need for a method of joining structural elements together that overcomes or mitigates one or more of the shortcomings or deficiencies of the prior art. In its broadest embodiments, the Disclosure provides a method for joining structural elements with one or more couplers. Each coupler includes a body and several fins positioned on the body. The method includes heating the couplers and the parts of the structural elements in an inert (non-oxidizing) atmosphere to a high working temperature to which the parts to be heated can be plastically deformed. When the parts to be heated reach the high working temperature, they engage and undergo engagement motion, in which one or more of the couplers and structural elements move relative to each other, and at least a portion of the parts to be heated undergoes shear due to their plastic deformation. A zone of recrystallized material is formed as a result of the plastic deformation joining the couplers and structural elements.

[0007] In another aspect of the present disclosure, providing a pair of structural elements, each of which includes an end portion, and the respective end portions of the pair of structural elements being positioned opposite each other; providing at least one coupler, each of which includes a body portion, and the body portion being positioned in close proximity to the respective end portions of the pair of structural elements; providing an inert atmosphere covering the coupler and the respective end portions of the pair of structural elements; heating the heated coupler section of at least one coupler to the hot working temperature of the coupler; heating the heated section of the end portion of the structural element to the hot working temperature of the structural element; and causing the at least one coupler and at least one selected one or both of the pair of structural elements to undergo translocation to engage the at least one coupler with the inner or outer surface of the respective end portion of the pair of structural elements. A method is provided which includes: subjecting at least one coupler and at least one or more of the pair of structural elements to an engaging motion in which the coupler and at least one or more of the pair of structural elements move relative to the other; and biasing at least one coupler at its end portion to the inner or outer surface of each of the pair of structural elements in order to join at least one coupler to the end portion of each of the structural elements.

[0008] In another embodiment, providing a coupler further includes providing a plurality of fins positioned on each body portion of at least one coupler for at least partial engagement with the inner surfaces of each end portion of a pair of structural elements. In yet another embodiment, providing a coupler further includes providing a plurality of fins positioned on each body portion of at least one coupler for at least partial engagement with the outer surfaces of each end portion of a pair of structural elements. In a further embodiment, heating the coupler heated section of the coupler to the coupler high working temperature and heating the structural element heated section of the end portion to the structural element high working temperature includes providing at least one heating element adjacent to the end portions of the pair of structural elements, energizing the at least one heating element to heat the coupler heated section and the structural element heated section, and removing the at least one heating element.

[0009] In a further embodiment, the end portions of each of the pair of structural elements include an inclined surface to form a cavity when the end portions engage, and the heated section of the coupler is pushed into the cavity during dislocation and / or engagement motion. In another embodiment, providing at least one coupler includes providing at least two couplers. In a further embodiment, the method includes inserting an intermediate element between at least two couplers to seal the gap between at least two couplers. In one embodiment, biasing at least one coupler at its end portion to the inner or outer surface of each of the pair of structural elements in order to join at least one coupler to the end portion of each structural element includes biasing at least one coupler at its end portion to both the inner and outer surfaces of each of the pair of structural elements in order to join at least one coupler to the end portion of each structural element.

[0010] This disclosure will be better understood with reference to the attached drawings. [Brief explanation of the drawing]

[0011] [Figure 1] A longitudinal cross-sectional view of an embodiment of two structural elements positioned such that their respective end portions face each other, and a coupler positioned at the proximal ends of the end portions. [Figure 2A] A longitudinal cross-sectional view of the structural element of FIG. 1 joined by the coupler of FIG. 1. [Figure 2B] A longitudinal cross-sectional view of the structural elements of FIGS. 1 and 2A joined by a coupler to form a product. [Figure 2C] A longitudinal cross-sectional view of a product formed by joining a structural element having an inclined surface with the coupler of FIG. 1. [Figure 3] A side view of another embodiment of two structural elements and a coupler positioned on the structural elements. [Figure 4] A longitudinal cross-sectional view of the coupler and the structural element of FIG. 3. [Figure 5] A longitudinal cross-sectional view of the coupler assembly and the structural element of FIGS. 3 and 4 along line A-A' of FIG. 3, showing the state where the coupler assembly joins the structural element. [Figure 6] An enlarged side view of two structural elements with several couplers positioned thereon. [Figure 7] A reduced side view of an alternative embodiment of the coupler of the present disclosure positioned to join a base and a structural element together. [Figure 8] A side view of a coupler joining two offset structural elements together. [Figure 9A] An enlarged side view of a coupler and an intermediate element joining the structural element together. [Figure 9B] An enlarged cross-sectional view of the coupler of FIG. 9A positioned to join the structural elements of FIG. 9A with an intermediate element positioned at the location between them. [Figure 9C] A cross-sectional view of the couplers of FIGS. 9A and 9B with an intermediate element positioned therebetween. [Figure 10]A longitudinal cross-sectional view of another alternative embodiment of the coupler of the present disclosure, engaging with the outer, inner, and end faces of each structural element. [Figure 11] A longitudinal cross-sectional view of another alternative embodiment of the coupler of the present disclosure, engaging with the outer, inner, and end faces of each structural element. [Figure 12] A longitudinal cross-sectional view of another alternative embodiment of the coupler of the present disclosure, engaging with the inner and end faces of each structural element. [Figure 13] A longitudinal cross-sectional view of the coupler of FIG. 12, where the coupler is joined to the end portions of each structural element. [Figure 14A] An enlarged cross-sectional view of an alternative embodiment of the coupler of the present disclosure positioned for engagement with the outer and inner faces of the structural element. [Figure 14B] A cross-sectional view of a product manufactured when the coupler of FIG. 14A is fixed to its structural element. [Figure 15A] A cross-sectional view of an alternative embodiment of the coupler of the present disclosure positioned for engagement with the outer and inner faces of the structural element. [Figure 15B] A cross-sectional view of a product manufactured when the coupler of FIG. 15A is fixed to its structural element. [Figure 16A] [[ID=2...]]A cross-sectional view of another alternative embodiment of the coupler of the present disclosure positioned for engagement in the cavity of the structural element. [Figure 16B] A cross-sectional view showing the coupler of FIG. 16A fixed in the cavity of the structural element. [Figure 17A] A cross-sectional view of another alternative embodiment of the coupler of the present disclosure positioned for engagement in the cavity of the structural element. [Figure 17B] A cross-sectional view showing the coupler of FIG. 17A fixed in the cavity of the structural element. [Figure 18A] A side view, drawn to scale, of another alternative embodiment of the structure and the coupler of the present disclosure, with one or more heating elements positioned therebetween. [Figure 18B] A top view of the structure and coupler of FIG. 18A. <...0121>Figures 18A and 18B are side views of the coupler and structure, showing the coupler fixed to the structure. [Figure 19A] This is a magnified cross-sectional view of a part of a structure having upper and lower plates, with several I-beams positioned between the upper and lower plates, and a coupler positioned to connect to the I-beams and upper and lower plates. [Figure 19B] This is a magnified cross-sectional view of a portion of the structure shown in Figure 19A, where an I-beam is joined to a lower plate by two couplers. [Figure 20] This is a scaled-down cross-sectional view of a portion of the structure shown in Figure 19A, which is joined to the lower and upper plates by I-beam couplers. [Figure 21] This is a longitudinal cross-sectional view of a part of the structure shown in Figure 20. [Figure 22A] This is a cross-sectional view of a part of a structure having curved upper and lower plates, with several I-beams positioned between the upper and lower plates, and a coupler positioned to be joined to the upper and lower plates. [Figure 22B] This is a magnified cross-sectional view of a portion of the structure shown in Figure 22A, where an I-beam is joined to a lower plate by two couplers. [Figure 23] This is a scaled-down cross-sectional view of a portion of the structure shown in Figure 22A, where the lower and upper plates are joined by I-beam couplers. [Figure 24] This is a longitudinal cross-sectional view of a part of the structure shown in Figure 23. [Figure 25] This is a longitudinal cross-sectional view of a part of the structure, where the upper and lower plates are curved in the longitudinal direction, and the I-beam is joined to the upper and lower plates by couplers. [Modes for carrying out the invention]

[0012] In the accompanying drawings, similar reference numerals indicate corresponding elements throughout. To illustrate embodiments of the method according to this disclosure, we first refer to Figures 1 and 2. In one embodiment, the method includes providing two structural elements 20A and 20B, each having an inner surface 22A and 22B. As can be seen in Figure 1, each of the structural elements 20A and 20B includes an end portion. For clarity in the illustration, the end portions are identified by reference numerals 24A and 24B (Figures 1 to 2B). As can be seen in Figure 1, the structural elements 20A and 20B are positioned such that their end portions 24A and 24B face each other.

[0013] Structural elements are understood to be made of one or more metals, such as steel. For this purpose, “metal” is understood to refer to a metallic element or an alloy containing two or more metallic elements. As shown in Figures 1 to 2B, in this embodiment, the structural elements 20A and 20B may be metal pipes with a circular cross-section that define the axis "X". However, those skilled in the art will acknowledge that the structural elements may have any cross-section that may be required for structural purposes. Furthermore, those skilled in the art will acknowledge that the cross-section of a structural element may vary along its length if required for structural or other purposes.

[0014] The joining of structural elements 20A and 20B includes a coupler 26. The coupler 26 includes a body 28 and several fins 30 or sets of fins 30 positioned on the body 28 for at least partial engagement with the inner surfaces 22A and 22B of the structural elements 20A and 20B. The coupler 26 may be made of one or more preferred metals, which may be the same as or different from the metal of the structural elements to be joined by the coupler 26. Examples of preferred materials include, but are not limited to, metals having a different or lower high-temperature working temperature than the metal of the structural elements.

[0015] After the coupler 26 and structural elements 20A, 20B are positioned, one or more heating elements 32 are provided for heating a portion or section of the coupler 26 (which may be seen as the first heated portion or coupler heated section 34) to the coupler's high working temperature, and for heating each portion or section of the end portions 24A, 24B of the respective structural elements 20A, 20B (which may be seen as the second heated portions of the end portions 24A, 24B or structural element heated sections 36A, 36B) to the structural element's high working temperature (Figure 1). The fins 30 are understood to be included in the first heated portion 34.

[0016] In one embodiment, the first and second heated parts 34, 36A, and 36B may be heated to different high-temperature working temperatures, for example, a first high-temperature working temperature and a second high-temperature working temperature. For example, the coupler 26 may be made of a first metal that is plastically deformable at the first high-temperature working temperature, and the structural elements 20A and 20B may be made of a second metal that is plastically deformable at the second high-temperature working temperature. For simplicity of explanation, only one high-temperature working temperature will be mentioned hereafter, but it will be understood that the high-temperature working temperature for the coupler and the high-temperature working temperature for the structural elements may be the same or different.

[0017] In Figure 1, the thicknesses of the first heated portion 34 and the second heated portions 36A and 36B are exaggerated for clarity in the illustration. The heating element can heat the part to be heated using any suitable heating method. In one embodiment, the heating element heats the part to be heated by induction. Those skilled in the art will recognize that, depending on the environment, the most energy-efficient arrangement may be to have separate heating elements 32 positioned and configured to heat each of the first and second parts to be heated 34, 36A, and 36B, respectively. However, for clarity in the illustration, it will be understood that only one heating element 32 is shown in Figure 1.

[0018] In some embodiments, during heating, an inert atmosphere is provided so as to cover the coupler 26 and at least the end portions 24A, 24B of the respective structural elements 20A, 20B. Those skilled in the art will know of gases that can form a suitable inert (non-oxidizing) atmosphere. A suitable container for containing the inert atmosphere is to be understood as being omitted from the figure for clarity.

[0019] Next, one or more heating elements 32 are energized to heat the first heated portion 34 and the second heated portions 36A, 36B to their respective high working temperatures. While the first heated portion 34 and the second heated portions 36A, 36B are at their respective high working temperatures, the coupler 26 and at least one selected one or both of the structural elements 20A, 20B undergo a dislocation motion to engage the coupler 26 with the inner surfaces 22A, 22B of the end portions of the respective structural elements 20A, 20B. More precisely, the first heated portion 34 engages with each of the second heated portions 36A, 36B as schematically shown in Figure 2B.

[0020] In the examples shown in Figures 1 to 2B, translation motion applied to structural elements 20A and 20B causes them to move in the directions indicated by arrows "A1" and "A2," respectively, while the structural elements 20A and 20B move linearly relative to the coupler 26, while the coupler 26 remains stationary. Other arrangements or sequences for displacement motion are also conceivable, as will be described. Those skilled in the art will recognize that the movement of the coupler and / or structural elements for engaging the first and second heated portions may occur in any preferred order, depending on the environment.

[0021] Furthermore, while the first heated section 34 and the second heated sections 36A and 36B are at their respective high working temperatures, the coupler 26 and one or more selected structural elements 20A and 20B undergo engagement motion, and the coupler 26 and one or more selected structural elements 20A and 20B move relative to the other. For example, in Figure 2A, the coupler 26 undergoes engagement motion, in which the coupler 26 moves relative to the structural elements 20A and 20B in the direction indicated by the arrow "B". The engagement motion may be any relative motion and may be repeated at regular intervals. For example, the coupler 26 may rotate or vibrate about axis "X".

[0022] The coupler 26 may also be biased against the inner surfaces 22A and 22B of the end portions 24A and 24B in order to join the coupler 26 to the end portions 24A and 24B of the respective structural elements 20A and 20B. For example, the coupler 26 may be biased outward against the inner surfaces 22A and 22B (Figure 2A). It will be understood that the means for biasing the coupler 26 against the structural elements 20A and 20B are omitted from Figures 1 to 2B for clarity in the illustration. Those skilled in the art will know of preferred means for biasing the coupler 26 against the structural elements 20A and 20B.

[0023] For clarity in the illustration, only a small number of fins 30 are shown in Figures 1 and 2A, and it should also be understood that the length of the fins 30 is exaggerated. Also for clarity in the illustration, the gap "G" shown between the body 28 and the inner surfaces 22A and 22B is exaggerated in Figure 2A for clarity in the illustration. Preferably, the fins 30 are at their high working temperature and undergo plastic deformation when they are compressed between the inner surfaces 22A and 22B and the body 28 (Figure 2A).

[0024] In Figure 2B, structural elements 20A and 20B are shown joined together by a coupler 26 to manufacture product 37. In the product, the fins 30 are compressed and plastically deformed between the coupler body 28 and the inner surfaces 22A and 22B of the end portions 24A and 24B.

[0025] As described above, only one heating element 32 is shown in Figures 1 and 2A for clarity in the illustrations; however, the configuration and positioning of at least one heating element 32 may be determined by actual considerations, such as the difficulties encountered when positioning the heating element inside a structural element, and when removing the heating element from its respective position or location when the first and second heated parts reach their respective high working temperatures.

[0026] When the heated parts reach their high working temperatures, they undergo plastic deformation. Since the high working temperatures are below the melting points of the metals of the coupler 26 and structural elements 20A and 20B, when the structural elements 20A and 20B and the coupler 26 are joined together using the method of the present disclosure, unlike conventional welding methods, the method of the present disclosure does not involve first melting the metal and then solidifying the metal.

[0027] When the heated parts reach their high working temperature and engage, the engaging motion causes the heated parts 34, 36A, and 36B to undergo at least partial shearing, forming zones or regions with a relatively uniform fine-grained microstructure that includes at least a portion of the heated parts and incorporates at least a portion of the inner surfaces 22A and 22B. It is believed that the relatively fine-grained microstructure arises from such shearing while the heated parts are at their high working temperature.

[0028] In one embodiment, it is also understood that the engagement motion of one or both of the structural elements and / or couplers may begin when the displacement motion starts. As can be seen in Figure 1, in one embodiment, the end portions 24A and 24B include their respective end faces 25A and 25B. In one embodiment, the end portions 24A and 24B may be positioned initially abutting or touching each other so that the end faces 25A and 25B engage with each other before heating. In this embodiment, the heating element 32 may be positioned, for example, between the coupler and the inner surfaces of the structural elements 20A and 20B. In this embodiment, when the first and second heated portions reach their high working temperatures, the heating element moves away from the coupler so as not to interfere with its engagement with the inner surfaces 22A and 22B. The coupler 26 undergoes dislocation motion and moves relative to the inner surfaces 22A and 22B, and the first and second structural elements 20A and 20B are biased toward each other. While the coupler 26 is biased against the inner surfaces 22A and 22B, and the structural elements 20A and 20B are biased against each other, one or both of the coupler and the end portions 24A and 24B move relative to each other in response to the engagement motion.

[0029] When the coupler 26 and end portions 24A and 24B engage, the temperatures of the first and second heated portions rapidly decrease from their high working temperatures. Plastic deformation is not possible when the temperature of the metal coupler or the end portion is below the high working temperature. This is because the coupler and end portions, once joined or bonded to each other, resist further engagement movement. Accordingly, when the resistance to engagement movement becomes sufficient, the engagement movement stops.

[0030] As the metal in the first and second heated portions 34, 36A, and 36B undergoes plastic deformation during the engagement motion, it is subjected to at least partial shear, and the coupler is biased against the inner surfaces 22A and 22B of the end portions 24A and 24B. Due to recrystallization caused by plastic deformation at the high working temperature, the coupler 26 is metallically joined to the end portions 24A and 24B. As described above, the recrystallized metal joining the coupler and the end portions 24A and 24B is relatively uniform and fine-grained. After shearing and cooling, the recrystallized zone of the metal extends (i) between the first heated portion 34 and the second heated portion 36A, and (ii) between the first heated portion 34 and the second heated portion 36B, integrating the affected portions and metallurgically joining them together. The inner surfaces 22A and 22B that engage with the fins 30, and at least a portion of the fins 30 that engage with the inner surfaces 22A and 22B when they reach a first high working temperature, are incorporated into the recrystallized metal. In Figure 2A, it is understood that the body 28 of the coupler 26 is shown with the fins 30 attached to it and separated from the inner surfaces 22A and 22B for clarity in the illustration.

[0031] Recrystallization of at least a portion of the heated portion is due to shearing of that portion. As described above, shearing can occur when the heated portion is heated to a selected high working temperature (or a selected range of high working temperatures) to which the heated portion of the coupler and end portion becomes plastically deformable.

[0032] Fins attached to the coupler body 28 facilitate the process of joining the coupler 26 to the structural elements 20A and 20B in two ways. Firstly, because the fins are generally much thinner than the coupler body, they heat up to a higher working temperature more quickly than the coupler body. Secondly, when the coupler engages with the structural elements, the fins, due to their smaller size, can plastically deform to fill any defined openings between the coupler body and either or both structural elements. Generally, a number of relatively small fins is preferred. For this purpose, a “fin” can be considered any projection above a surface adjacent to such a projection, and it is understood that a fin may be, for example, a long filament extending from the surface of a small ridge on the coupler body, or a small fold, or associated with the remaining material after some holes have been formed in the material.

[0033] In environments where structural elements 20A and 20B do not need to be intended to carry fluid in or through them, the position of the coupler on the internal surface does not adversely affect the fluid flow, so the coupler 26 can have any suitable configuration. In connection with this, the connection of the coupler to the end portion does not need to be liquid-tight.

[0034] When the coupler 26 is biased against the inner surfaces 22A, 22B, a portion of the plastically deformable material may be extruded from the region between the body 28 and the inner surfaces 22A, 22B. For example, a portion of the fins may also be extruded. Accordingly, in one embodiment, one or both of the end portions 24A, 24B may include inclined surfaces that partially define a cavity into which the plastically deformable and extruded material is received.

[0035] As can be seen in Figure 2C, in one embodiment, the structural elements 20A and 20B include their respective inclined surfaces 40A and 40B. In Figure 2C, it is understood that the structural elements 20A and 20B and the coupler 26 are shown after they have been joined together to form a product identified by reference numeral 37'.

[0036] The inclined surfaces 40A and 40B partially define a cavity 42 in which the extruded material 44 can be received (Figure 2C). As can be seen in Figure 2C, once the product 37' is formed, the cavity 42 is also partially defined by the inner surface 46 of the body 28 of the coupler 26. It will be understood that the fins 30 have been omitted from Figure 2C for clarity in the illustration.

[0037] When the respective heated portions 34, 36A, and 34, 36B engage and the plastically deformable material within them is sheared, it is believed that at least a portion of the heated portions 34, 36A, and 36B (including the fins) will be compressed or pushed into the cavity 42.

[0038] In an alternative embodiment, the coupler may be attached to the outer surface of the structural element. In one embodiment, the method of the present disclosure includes, firstly, providing two structural elements 120A and 120B having outer surfaces 138A and 138B, respectively, as can be seen in Figures 3 and 4. Each of the structural elements 120A and 120B includes its end portion.

[0039] As can be seen in Figure 3, a side view of a pair of structural elements, the structural elements 120A and 120B abut each other and define a seam "S" between them. In Figure 4, the coupler 126 is shown at the position where the first heated portion 134 is heated by the heating element 132, and in Figure 5, the coupler 126 is shown with its fins 130 engaged with the structural elements 120A and 120B. Figure 5 is a longitudinal cross-sectional view along the line A-A' in Figure 3.

[0040] In this embodiment, the coupler 126 includes a body 128 and several fins 130 positioned on the body 128 for at least partial engagement with the outer surfaces 138A and 138B of the structural elements 120A and 120B (Figure 4).

[0041] For clarity in the illustration, the end portions are identified by reference numerals 124A and 124B in Figures 3 to 5. The structural elements 120A and 120B are positioned such that their end portions 124A and 124B engage with each other. In one embodiment, as shown in Figures 3 and 4, the structural elements 120A and 120B are positioned such that their end portions 124A and 124B engage with and align with each other.

[0042] It should be understood that structural elements 120A and 120B may not be fully shown in Figures 4 and 5. Structural elements 120A and 120B may have any suitable cross-section, for example, they may be metal pipes with a round cross-section.

[0043] One or more heating elements 132 are provided to heat the first heated portion 134 of the coupler 126 to a high working temperature and to heat the respective second heated portions 136A and 136B of the end portions 124A and 124B of the respective structural elements 120A and 120B to their respective working temperatures (Figure 3). At least one heating element 132 is configured and positioned to heat the first and second heated portions 134, 136A and 136B in any preferred manner, such as induction heating, although other methods for heating the heated portions are also conceivable.

[0044] In the diagram, the range or size of the first and second heated portions 134, 136A, and 136B are exaggerated for clarity. Generally, the heated portions are thinner than those shown.

[0045] In one embodiment, as schematically shown in Figure 4, only one heating element 132 may be required. Two or more heating elements may be used; for example, three elements may be required, one for each of the heated parts 134, 136A, and 136B, as will be recognized by those skilled in the art.

[0046] An inert atmosphere is provided to cover the coupler 126 and at least the end portions 124A, 124B of the respective structural elements. The inert atmosphere is preferably contained in a container (not shown). For clarity in the illustration, it is understood that the container for the inert atmosphere is omitted from Figures 3 and 4.

[0047] Next, one or more heating elements 132 are energized to heat the first and second heated parts 134, 136A, and 136B to their high working temperatures. While the first and second heated portions 134, 136A, and 136B are at their high working temperatures, the coupler 126 undergoes displacement motion (i.e., in the direction indicated by arrow "2B" in Figure 5), engaging the coupler 126 with the outer surfaces 138A and 138B of the respective end portions of the structural elements. The end portions 124A and 124B are also biased toward each other in the directions indicated by arrows "2A1" and "2A2" in Figure 5.

[0048] Depending on the environment or scenario, the positioning of coupler 126 relative to structural elements 120A and 120B does not need to be precise. While the first and second heated parts are at their high working temperatures, one or more of the coupler 126 and one or both of the structural elements 120A, 120B undergo engagement motion, and the coupler and one or more of the structural elements move relative to the other. For example, the coupler 126 and one or more of the structural elements 120A, 120B may rotate or vibrate about an axis (not shown) of the structural elements 120A, 120B, or the coupler may move parallel to the axis (i.e., in the direction indicated by the arrow "2C" in Figure 5).

[0049] In environments where structural elements 120A and 120B do not move easily, only the coupler 126 undergoes engagement motion. The coupler is biased against the outer surface of the end portion, and while the first and second heated portions are at their high working temperatures, the first heated portion 134 and the second heated portions 136A, 136B undergo shear and plastic deformation. Due to the shearing of the first and second heated portions in response to at least one of translational or engagement motions, a single metallurgically bonded zone is formed containing a fine-grained microstructure extending through the first and second heated portions, and the original end faces of the end portions, as well as the fins (and / or the surfaces of the coupler in contact with the outer surface) are at least partially incorporated into the new zone of fine-grained microstructure, thereby joining the coupler to the outer surface of the end portion of each structural element.

[0050] In another embodiment, as shown in Figure 6, two or more couplers may be positioned on the outer surfaces of two adjacent structural elements 220A, 220B and spaced radially from each other to provide a relatively strong joint between them. For example, the structural elements 220A, 220B may be part of a tower (not fully shown), such as a tower built to support a wind turbine. In Figure 6, the structural elements 220A, 220B engage with each other to define a seam "2S" between them.

[0051] As shown in Figure 6, structural elements 220A and 220B may be connected by two or more couplers identified by reference numerals 226A, 226B, and 226C in Figure 6. It is understood that the couplers may be fixed to structural elements 220A and 220B using the techniques described above. It is understood that the heating elements have been omitted from Figure 6 for clarity in the illustration.

[0052] Only the bodies of the couplers 226A, 226B, and 226C are shown in Figure 6, and it is understood that the fins of the couplers 226A, 226B, and 226C are omitted from Figure 6. In the embodiment shown in Figure 6, the couplers 226A, 226B, and 226C are fixed to the outer surfaces 238A and 238B of the structural elements 220A and 220B, respectively, and extend across the seam "2S".

[0053] Those skilled in the art will recognize that alternative or further couplers may be fixed to the inner surfaces (not shown in Figure 6) of the respective structural elements 220A and 220B. In some embodiments, when the connection between structural elements 220A and 220B does not need to be liquid-tight, the couplers 226A, 226B, and 226C are spaced apart from each other (as shown in Figure 6).

[0054] Further embodiments of a coupler that may be used to connect workpieces or structural elements having non-aligned outer surfaces are shown, as can be seen in Figures 7 and 8. For example, in Figure 7, structural element 320A has an outer surface 338A positioned to define an acute angle with respect to a common axis "3X". Another structural element 320B has an outer surface 338B that aligns with axis "3X". In Figure 7, structural elements 320A and 320B engage with each other so as to define a seam "3S" between them. As can be seen in Figure 7, a coupler 326 is formed to interlock with both of the two non-aligned outer surfaces. The coupler 326 can be fixed to structural elements 320A and 320B using the technique described above. Heating elements are omitted for clarity in the illustration.

[0055] It is understood that the fins 330 can be sized and positioned to fill such gaps so that they are between the body 328 and the structural elements 320A and 320B when the coupler 326 engages with the structural elements.

[0056] From the above, it can be seen that several couplers may be used to join structural elements 320A and 320B, that is, they may be positioned across the seam "3S". It is understood that only one coupler is shown in Figure 7 for the sake of simplicity.

[0057] In Figure 8, the outer surfaces 438A and 438B of structural elements 420A and 420B are parallel to axes "4X1" and "4X2," respectively, but are offset from each other because the axes are not aligned. In Figure 8, structural elements 420A and 420B engage with each other and define a seam "4S" between them. Couplers 426A and 426B are spaced radially apart from each other and are positioned to connect structural elements 420A and 420B. It is understood that the couplers can be connected to structural elements 420A and 420B using the technique described above. Heating elements are omitted for clarity in the illustration.

[0058] It is understood that the fins 430 can be sized and positioned to fill such gaps, as they are located between the main body 428A, 428B and the outer surfaces 438A, 438B of the structural elements 420A, 420B when the coupler engages with the structural elements.

[0059] Another alternative embodiment of the method or system of this disclosure is disclosed in Figures 9A and 9C. As can be seen in Figure 9A, structural elements 520A and 520B engage with each other to define a seam "5S" between them. Couplers 526A and 526B are joined to the outer surfaces 538A and 538B of the structural elements across the seam "5S". The couplers are fixed to the outer surfaces of the structural elements as described above. However, in Figure 9A, an intermediate element 550 is also shown positioned between the couplers 526A and 526B. The manner in which the intermediate element 550 is joined to the structural elements 520A and 520B is shown in Figures 9B and 9C and will be described in more detail below.

[0060] In Figures 9A to 9C, the intermediate element 550 is used to seal the gap 552 defined between couplers 526A and 526B. In some embodiments, it may be desirable to seal the gap 552 (Figure 9B), for example, when it is intended to provide a liquid-tight seal along the seam "5S".

[0061] Figure 9C is a cross-sectional view along the line B-B' in Figure 9A. In this situation, the surfaces 554A and 554B of the respective couplers 526A and 526B can be prepared for engagement with the intermediate element 550, for example, so that the intermediate element 550 fits into the gap 552 (Figure 9B).

[0062] As can be seen in Figure 9B, the intermediate element 550 includes one or more intermediate surfaces 556 from which several fins 558 protrude, the intermediate surfaces 556 are formed to coincide with surfaces 554A, 554B, and the fins 558 are pressed between them. As can be seen in Figures 9B and 9C, the intermediate element 550 includes a surface 557 that engages with the outer surfaces 538A, 538B when the intermediate element 550 is positioned in the gap 552.

[0063] Each of the couplers, intermediate elements, and structural elements includes a section that is heated to facilitate engagement between the components. As in the embodiments described above, the heated section is covered with an inert atmosphere (not shown). It is understood that one or more heating elements (not shown in Figure 9B) are positioned to heat the first heated section (not shown) of each coupler 526A, 526B to a high working temperature. It is understood that the heated sections are positioned on the respective surfaces 554A, 554B. The coupler may include the heated section within the surface that engages with the structural element.

[0064] One or more heating elements (not shown in Figure 9B) are positioned to heat one or more heated parts (not shown) of the surrounding (immediate) element 550 to the high working temperature of the intermediate element. The fins 558 are understood to be included in the heated parts of the intermediate element 550.

[0065] The joining between the coupler, the intermediate element, and the outer surface can generally be carried out as described above. While the heated portions of the coupler and the intermediate element are at their respective working temperatures, the intermediate element 550 moves in the direction indicated by arrow "5A" to engage the fins 558 with surfaces 554A and 554B (Figure 9B). Once engaged, the intermediate element 550 continues to be biased in the direction indicated by arrow "5A" until the heated portions are joined together at least partially. Also, while the intermediate element 550 is biased against surfaces 554A and 554B, and the heated portions of the intermediate element and the coupler are at their respective working temperatures, the intermediate element vibrates in the gap 552, causing plastic deformation of at least a portion of the heated portions of the engaged coupler and intermediate element.

[0066] As can be seen in Figures 9A and 9C, the intermediate element 550 is also positioned between the couplers 526A and 526B and engages with both sides of the outer surfaces 538A and 538B or the seam "5S".

[0067] As described above, due to plastic deformation, surfaces 554A, 554B, intermediate surface 556, and surface 557 are incorporated into a recrystallized material with a relatively fine-grained microstructure, and the zone of recrystallized material extending over the intermediate element and couplers 526A, 526B is joined together with the intermediate element 550 and couplers 526A, 526B by metallurgical joining.

[0068] For example, if we want to provide a liquid-tight seal along the length of seam "5S", those skilled in the art will recognize that embodiments of the method shown in Figures 9A to 9C can be used. Although only two couplers and one intermediate element are shown in Figures 9A to 9C, other embodiments may have more couplers with intermediate elements in between.

[0069] In another alternative embodiment, the coupler 626 includes internal and external assemblies or bodies 627A, 627B connected by a central portion 660 (Figure 10). As described, the internal assembly 627A includes an internal body 628A, and the external assembly 627B includes an external body 628B. The structural elements 620A, 620B include their respective end faces 625A, 625B at the ends of their respective end portions 624A, 624B. The structural elements 620A, 620B are initially spaced apart from each other.

[0070] The coupler 626 is initially positioned such that the central portion 660 is located between the end portions 624A, 624B or the end faces. The central portion 660 includes inner surfaces 662A, 662B that face the end faces 625A, 625B, respectively.

[0071] In this embodiment, the internal assembly 627A includes a fin 630A extending from the main body 628A, and the external assembly 627B includes a fin 630B extending from the main body 628B. The fin 630B is positioned to engage with the outer surfaces 638A, 638B of the end portions 624A, 624B, and the fin 630A is positioned to engage with the inner surfaces 622A, 622B of the end portions 624A, 624B.

[0072] In the example shown in Figure 10, the structural elements 620A and 620B are shown as flat plates, with their outer surfaces 638A and 638B and inner surfaces 622A and 622B being parallel. Those skilled in the art will recognize that couplers 626 may be used to join structural elements that are not generally flat but are curved. For curved structural elements, the bodies 628A and 628B may be molded accordingly.

[0073] It is understood that heating elements (not shown) are provided to heat the section or portion of the internal assembly 627A considered to be the first heated section, the section or portion of the external assembly 627B considered to be the second heated section, and the section or portion of the central section 660 considered to be the third heated section to a high working temperature. The structural elements also include heated areas (considered heated sections) that are heated to a high working temperature. It is also understood that, for clarity in the illustration, heating elements are omitted from Figure 10 and heated sections are not identified.

[0074] As shown in Figure 10, the gaps between the internal body 628A and the inner surfaces 622A and 622B, and the gaps between the external body 628B and the outer surfaces 638A and 638B are exaggerated for clarity in the illustration.

[0075] While each heated portion is at its high working temperature, the first and second structural elements 620A and 620B move toward each other in the directions indicated by arrows "6A1" and "6A2," engaging their end faces 625A and 625B with the inner surfaces 662A and 662B of the central portion 660, respectively. Immediately thereafter, the internal and external assemblies 627A and 627B are biased inward, i.e., in the directions indicated by arrows "6B1" and "6B2." When the fins 630A and 630B engage with the inner and outer surfaces 622A, 622B, 638A, and 638B, the coupler 626 and one or more of the structural elements 620A and 620B move relative to each other (e.g., via engagement motion) while the inner and outer assemblies 627A and 627B are biased in the directions indicated by arrows "6B1" and "6B2," resulting in at least partial plastic deformation of the heated portion. The plastic deformation causes shearing of the engaged material, resulting in the coupler 626 being metallurgically bonded to the end portions 624A and 624B as described above.

[0076] One or more of the structural elements 620A, 620B, the internal and external bodies 628A, 628B, and the central portion 660 may include one or more inclined surfaces. When the coupler 626 is joined to the structural elements 620A, 620B, the inclined surfaces are formed to define one or more cavities into which at least a portion of plastically deformable material can be extruded.

[0077] In another alternative embodiment, as schematically shown in Figure 11, the coupler 726 includes internal and external assemblies 727A and 727B having different lengths. For example, the coupler 726 may be used when the exterior (not shown) of the completed system will have minimal obstacles, i.e., the exterior will be somewhat simplified, but the interior of the completed system may have substantial obstacles. For example, the coupler 726 may be used when structural elements 720A and 720B form the external shell of an automobile. In these environments, it is desirable that the external assembly 727B includes a body 728B of minimal or shorter length, and the internal assembly 727A may include a body 728A of any suitable length. The internal and external assemblies are connected by a central portion 760.

[0078] As can be seen in Figure 11, the assemblies 727A and 727B also include fins 730A and 730B attached to their respective bodies 728A and 728B. The outer surfaces of structural elements 720A and 720B are identified by reference numerals 738A and 738B, respectively. The inner surfaces of structural elements 720A and 720B are identified by reference numerals 722A and 722B, respectively.

[0079] The heated parts (not shown) of the internal and external assemblies, the central portion, and the end portions 724A and 724B of the structural elements are heated to their high working temperatures by one or more heating elements (not shown) in an inert atmosphere. The heated parts include at least a portion of the fins 730A and 730B.

[0080] It is understood that the heating element and the heated part have been omitted from Figure 11 for clarity in the illustration. It is also understood that, for clarity in the illustration, the gaps between the main body and the inner surfaces 722A, 722B and the outer surfaces 738A, 738B have been exaggerated, and the lengths of the fins 730A, 730B have also been exaggerated.

[0081] While the heated parts are at their respective high working temperatures, the coupler 726 engages with the end portions 724A and 724B. In the same or similar manner as described above, the coupler and end portions engage while being biased together (e.g., via dislocation motion) and also moving relative to each other by engagement motion. As described above, a zone with a relatively fine-grained microstructure is created in the material.

[0082] It is understood that one or more of the structural elements 720A, 720B, the internal and external bodies 728A, 728B, and the central portion 760 may include one or more inclined surfaces. When the coupler 726 is joined to the structural elements 720A, 720B, the inclined surfaces are formed to define one or more cavities into which at least a portion of plastically deformable material can be extruded.

[0083] In another alternative embodiment shown in Figures 12 and 13, the coupler 826 includes an internal assembly 827 and a central portion 860. As can be seen in Figure 12, the two structural elements 820A, 820B are initially spaced apart to define a gap between the end faces 825A, 825B of the end portions 824A, 824B. The internal assembly 827 includes an internal body 828 and several fins 830 or sets of fins 830 extending from the body toward the inner surfaces 822A, 822B of the end portions 824A, 824B.

[0084] As can be seen in Figure 12, the central portion 860 includes inner surfaces 862A and 862B facing the end faces 825A and 825B, respectively. A heating element (not shown) is provided to heat (ii) sections of end portions 824A and 824B (considered to be heated parts of end portions 824A and 824B), (ii) sections of internal assembly 827 (considered to be heated parts of internal assembly 827), and (iii) sections of central portion (considered to be heated parts of central portion 860) to their high working temperatures.

[0085] While the heated parts are at their respective high working temperatures, one or both of the structural elements 820A and 820B move (displace) in the directions indicated by arrows "8A1" and "8A2" in Figure 13, respectively, to engage the end faces 825A and 825B with the inner surfaces 862A and 862B of the central portion 860. At the same time, the coupler 826 is biased (engaged) in the direction indicated by arrow "8B," biasing the fins 830 against the inner surfaces 822A and 822B.

[0086] As described above, the heated parts are at their respective high working temperatures, and while the coupler 826 engages with the structural elements 820A and 820B, one or more of the coupler 826 and structural elements 820A and 820B move relative to each other, and at least a portion of the heated parts is subjected to shear due to their plastic deformation. As described above, the result is that the structural elements and the coupler are metallurgically joined together.

[0087] In some embodiments, one or more of the structural elements 820A, 820B, the body 828, and the central portion 860 may include one or more inclined surfaces. When the coupler 826 is joined to the structural elements 820A, 820B, the inclined surfaces are formed to define one or more cavities into which at least a portion of plastically deformable material can be extruded.

[0088] In another alternative embodiment, internal and external couplers 926A, 926B may be used to join structural elements 920A, 920B, as shown in Figures 14A and 14B. As described, one or both of the couplers 926A, 926B may be used. As can be seen in Figures 14A and 14B, the structural elements 920A, 920B are positioned to define a gap 952 between them, but alternatively, the structural elements 920A, 920B may engage with each other to close the gap 952.

[0089] As can be seen in Figure 14A, in one embodiment, each of the couplers 926A and 926B includes several fins 930A and 930B. The lengths of the fins shown in Figure 14A are exaggerated for illustrative purposes.

[0090] Structural elements 920A and 920B are formed to define a substantially arc shape, and the internal coupler 926A includes a body 928A formed to interlock with the respective inner surfaces 922A and 922B of structural elements 920A and 920B. Similarly, the external coupler 926B includes a body 928B molded to interlock with the respective outer surfaces 938A and 938B of structural elements 920A and 920B. In this embodiment, each of the bodies 928A and 928B has a surface 946A and 946B molded to interlock relatively tightly with structural elements 920A and 920B. In some embodiments, each of the surfaces 946A, 946B is formed to accommodate fins compressed between the respective bodies 928A, 928B and the corresponding surfaces of the structural elements 920A, 920B after the coupler and sections of the structural elements have been heated to their respective high working temperatures and subjected to at least one of translational and engagement motions.

[0091] In one embodiment, one or more heating elements (not shown) are positioned between the coupler 926A and the inner surfaces 922A, 922B. Similarly, one or more heating elements (not shown) are positioned between the coupler 926B and the outer surfaces 938A, 938B. The coupler and at least a portion of the inner and outer surfaces 922A, 922B, 938A, 938B are preferably covered with an inert atmosphere. It is understood that the heating elements and the containers for holding the inert atmosphere in place are omitted from Figures 14A and 14B for clarity in the illustration.

[0092] The heating element is then energized to heat the sections of couplers 926A and 926B or the heated parts in an inert atmosphere to a high working temperature. In one embodiment, heating is by induction. Preferably, the heated parts of the coupler include at least a portion of the fins 930A and 930B, respectively.

[0093] It is understood that the heated portions adjacent to the inner surfaces 922A and 922B of structural elements 920A and 920B, and the heated portions adjacent to the outer surfaces 938A and 938B of structural elements 920A and 920B, have also been omitted for clarity in the illustration.

[0094] While the heated portions 934A, 936A, and 936B are at their respective high working temperatures, the coupler 926A engages with the inner surfaces 922A and 922B of the structural elements 920A and 920B. In much the same manner as described above, during engagement, and while the heated portions 934A, 936A, and 936B are at their respective high working temperatures, the coupler 926A undergoes an engagement motion, resulting in plastic deformation of at least a portion of the material in the heated portion, and the heated portion 934A is at least partially metallurgically bonded to the heated portions 936A and 936B. As described above, the engagement motion can be any motion of one or both of the coupler and structural elements relative to the other. A zone of recrystallized metal with a relatively fine-grained microstructure is created over at least a portion of the heated portion. Surfaces 946A, 922A, and 922B are at least partially incorporated into the recrystallized zone.

[0095] Similarly, while the heated portions 934B, 935A, and 935B are at their respective high working temperatures, the coupler 926B engages with the outer surfaces 938A and 938B. In much the same manner as described above, upon engagement, and while the heated portions 934B, 935A, and 935B are at their high working temperatures, the coupler 926B preferably undergoes an engaging motion, resulting in plastic deformation of at least a portion of the material in the heated portions, and the heated portion 934B is at least partially metallurgically bonded to the heated portions 935A and 935B. As described above, a zone of metal having a relatively fine-grained microstructure is created. The surfaces 946B, 938A, and 938B are at least partially incorporated into the recrystallization zone.

[0096] As shown in Figure 14B, when the couplers 926A and 926B are joined to the structural elements 920A and 920B, product 937 is formed. For clarity in the illustration, it should be understood that the fins 930A and 930B have been omitted from Figure 14B.

[0097] In some embodiments, one or more of the structural elements 920A, 920B and the coupler bodies 928A, 928B include one or more inclined surfaces. When the couplers 926A, 926B are joined to the structural elements 920A, 920B, the inclined surfaces are formed to define one or more cavities into which at least a portion of a plastically deformable material can be extruded.

[0098] In another alternative embodiment shown in Figures 15A and 15B, internal and external couplers 1026A and 1026B may be used to join structural elements 1020A and 1020B. As described, one or both of the couplers 1026A and 1026B may be used. As can be seen in Figures 15A and 15B, the structural elements 1020A and 1020B may be positioned to define a gap 1052 between them, but alternatively, the structural elements 1020A and 1020B may engage with each other to close the gap 1052.

[0099] As can be seen in Figure 15A, in one embodiment, each of the couplers 1026A and 1026B includes several fins 1030A and 1030B. The lengths of the fins shown in Figure 15A are exaggerated for clarity in the illustration.

[0100] Structural element 1020A is formed to define a substantially arched shape. However, in the example shown in Figures 15A and 15B, structural element 1020B has a substantially linear shape. The respective end faces 1025A and 1025B of structural elements 1020A and 1020B define a gap 1052 between them. Coupler 1026A includes a body 1028A molded to fit into the respective end faces 1025A and 1025B of structural elements 120A and 120B. Coupler 1026B also includes a body 1028B molded to fit into the respective outer surfaces 1038A and 1038B of structural elements 1020A and 1020B.

[0101] Body 1028A includes one or more surfaces 1046A formed to interlock with end faces 1025A, 1025B. Body 1028B has surfaces 1046B formed to interlock relatively tightly with the outer surfaces 1038A, 1038B of structural elements 1020A, 1020B. Those skilled in the art will recognize that surfaces 1046A, 1046B are formed to accommodate fins 1030A, 1030B when the couplers 1026A, 1026B engage with structural elements 1020A, 1020B.

[0102] As described above, in some embodiments, only the internal coupler 1026A is used to join the structural elements 1020A and 1020B. Alternatively, in other embodiments, only the external coupler 1026B is used to join the structural elements 1020A and 1020B. In the following description, however, both couplers 1026A and 1026B are used to join the structural elements 1020A and 1020B.

[0103] In one embodiment, one or more heating elements (not shown) are positioned between the coupler 1026A and the end faces 1025A, 1025B. Similarly, one or more heating elements (not shown) are positioned between the coupler 1026B and the outer surfaces 1038A, 1038B. At least portions of the coupler, the end faces 1025A, 1025B, and the outer surfaces 1038A, 1038B are preferably covered with an inert atmosphere. It is understood that containers for holding the heating elements and the inert atmosphere in place are omitted from Figures 15A and 15B for clarity in the illustration.

[0104] The heating element is then energized to heat the sections of couplers 1025A and 1026B (considered to be the heated parts 1034A and 1034B of the couplers) to their high working temperatures, for example by induction. The heated parts 1034A and 1034B each include at least a portion of the fins 1030A and 1030B.

[0105] Other heated parts of structural elements 1020A and 1020B (also called heated structural elements) are also heated to their high working temperatures by energized heating elements in an inert atmosphere. The heated parts of structural elements 1020A and 1020B adjacent to end faces 1025A and 1025B are identified by reference numerals 1036A and 1036B, respectively. The heated parts of structural elements 1020A and 1020B adjacent to outer faces 1038A and 1038B are identified by reference numerals 1035A and 1035B, respectively. For clarity in the illustration, it should be understood that the extent of the heated parts is exaggerated in Figure 15A. When the heated parts reach their high working temperatures, they undergo plastic deformation.

[0106] While the heated parts 1034A, 1036A, and 1036B are at their high working temperatures, the coupler 1026A moves in the direction indicated by the arrow "10A" (which can be considered a dislocation motion) and engages with the end faces 1025A and 1025B of the structural elements 1020A and 1020B. In much the same manner as described above, upon engagement, and while the heated parts 1034A, 1036A, and 1036B are at their high working temperatures, the coupler 1026A undergoes engagement motion, resulting in plastic deformation of at least a portion of the material in the heated parts, and the heated part 1034A is at least partially metallurgically bonded to the heated parts 1036A and 1036B. As described above, a zone of recrystallized metal with a relatively fine-grained microstructure is created. Surfaces 1046A, 1022A, and 1022B are at least partially incorporated into the recrystallized zone.

[0107] Similarly, while the heated parts 1034B, 1035A, and 1035B are at their high working temperatures, the coupler 1026B moves toward the surfaces 1038A, 1038B of the structural elements 1020A, 1020B until the coupler 1026B engages with the outer surfaces 1038A, 1038B. In much the same manner as described above, upon engagement, and while the heated parts 1034B, 1035A, and 1035B are at their high working temperatures, the coupler 1026B undergoes an engaging motion, resulting in plastic deformation of at least a portion of the material in the heated parts, and the heated part 1034B is at least partially metallurgically bonded to the heated parts 1035A, 1035B. As described above, a zone of metal with a relatively fine-grained microstructure is created. The surfaces 1046B, 1038A, and 1038B are at least partially incorporated into the recrystallization zone.

[0108] Structural elements 1020A and 1020B may have different thicknesses and may be made of different materials, which means that the high-temperature working temperatures for their respective heated parts may be different.

[0109] As shown in Figure 15B, when the couplers 1026A and 1026B are joined to the structural elements 1020A and 1020B, product 1037 is formed. It is also understood that at least one of the structural elements 1020A, 1020B and the coupler bodies 1028A, 1028B may include one or more inclined surfaces. The inclined surfaces are formed to define one or more cavities into which at least a portion of plastically deformable material can be extruded when the couplers 1026A, 1026B are joined to the structural elements 1020A, 1020B.

[0110] In another alternative embodiment, the coupler 1126 may be joined to the structural element 1120, as schematically shown in Figures 16A and 16B. The coupler 1126 includes a body 1128 with several fins 1130 or a set of fins 1130 protruding from the body 1128. The lengths of the fins shown in Figure 16A are exaggerated for clarity in the illustration.

[0111] In the embodiments of Figures 16 and 16B, the structural element 1120 includes a receptacle 1170 defined by one or more side walls 1172 and an end wall 1174. As can be seen in Figures 16A and 16B, the body 1128 of the coupler 1126 includes a forming portion 1175 having a tapered wall 1176 and an end wall 1178. The tapered wall 1176 is formed so that the forming portion 1175 and the fins 1130 positioned therein interlock within the receptacle 1170. When the forming portion 1175 is fully accepted into the receptacle 1170, it is preferable that a small gap 1171 is defined between the end wall 1178 and the end wall 1174 of the receptacle (Figure 16B).

[0112] In one embodiment, the structural element 1120 may include one or more fins 1131 that can be attached, for example, to the side wall 1172 and / or end wall 1174. One or more heating elements (not shown) are positioned between the coupler 1126 and the side wall 1172 and end wall 1174. The forming portion 1175, side wall 1172 and end wall 1174 are covered with an inert atmosphere. It is understood that the containers for holding the heating elements and the inert atmosphere in place are omitted from Figures 16A and 16B for clarity in the illustration.

[0113] The heating element is then energized to heat a section of the coupler 1126 (considered the heated portion of the coupler) to a high working temperature in an inert atmosphere. The heated portion includes at least a portion of the fin 1130. It is also preferable that the heating element (not shown in Figures 16A and 16B) be positioned at least partially on the receptacle 1170 to heat a portion of the side wall 1172 (considered the heated portion of the structural element) and a portion of the end wall 1174. It is understood that the heated portions are heated to a high working temperature to which they can be plastically deformed.

[0114] While the heated parts are at their high working temperature, the coupler 1126 is pushed into the receptacle 1170, i.e., in the direction indicated by arrow "11A" in Figure 16B, for example, via dislocation motion. In substantially the same manner as described above, during engagement and while the heated parts are at their high working temperature, the coupler 1126 undergoes engagement motion, resulting in plastic deformation of at least a portion of the material in the heated parts. As described above, the engagement motion can be any motion of one or both of the coupler and the structural element relative to the other. While the coupler 1126 undergoes engagement motion, it is preferable that the coupler 1126 is biased relative to the structural element 1120 in the direction indicated by arrow "11A".

[0115] During the high working temperature, the heated portion of the forming part 1175 of the main body 1128 and the heated portion of the side wall 1172 engage with each other, causing at least partial plastic deformation of the heated portion. As described above, the plastic deformation creates a zone of recrystallized metal having a relatively fine-grained microstructure. The surfaces of the side walls 1172 and 1176 are at least partially incorporated into the recrystallized zone.

[0116] As shown in Figure 16B, when the coupler 1126 is joined to the structural element 1120, product 1137 is formed. It is understood that the fins 1130 and 1131 have been omitted from Figure 16B for clarity in the illustration.

[0117] It is also understood that one or more of the structural element 1120 and the coupler body 1128 may include one or more cavities 1142, which are positioned and sized such that at least a portion of the plastically deformable material can be extruded into the cavities 1142 when the coupler 1126 is joined to the structural element 1120.

[0118] In another alternative embodiment shown in Figures 17A and 17B, the coupler 1226 may be joined to the structural element 1220. The coupler 1226 includes a body 1228. As can be seen in Figure 17A, in one embodiment, the coupler 1226 includes several fins 1230 protruding from the body 1228. The lengths of the fins shown in Figure 17A are exaggerated for clarity in the illustration.

[0119] The structural element 1220 includes a receptacle 1270 defined by one or more walls 1272 and a rounded end wall 1274. As can be seen in Figures 17A and 17B, the body 1228 of the coupler 1226 includes a forming portion 1275 having one or more walls 1276 and a rounded end wall 1278. Preferably, the walls 1276 and the end wall 1274 are formed so that the forming portion 1275 and the fins 1230 positioned therein interlock within the receptacle 1270. When the forming portion 1275 is fully accepted into the receptacle 1270, it is preferable that a small gap 1271 is defined between the coupler's end wall 1278 and the receptacle's end wall 1274 (Figure 17B).

[0120] In one embodiment, the structural element 1220 may include one or more fins 1231 that can be attached to or integrated with, for example, a wall 1272 and / or an end wall 1274 of a receptacle.

[0121] One or more heating elements (not shown) are positioned between the coupler 1226, the side wall 1272, and the end wall 1274 of the receptacle. The forming portion 1275, the wall 1272, and the end wall 1274 are preferably covered with an inert atmosphere. It is understood that the containers for holding the heating elements and the inert atmosphere in place are omitted from Figures 17A and 17B for clarity in the illustration.

[0122] The heating element is then energized to heat a section of the coupler 1226 (considered to be the heated portion of the coupler) to a high working temperature in an inert atmosphere. Each heated portion includes at least a portion of the fin 1230. It is also preferable that heating elements (not shown in Figures 17A and 17B) be positioned at least partially on the receptacle 1270 to heat a portion of the wall 1272 and a portion of the end wall 1274. The heated portions are understood to be heated to a high working temperature to which they can be plastically deformed.

[0123] While the heated parts are at their high working temperatures, the coupler 1226 is pushed into the receptacle 1270, i.e., in the direction indicated by arrow "12A" in Figure 17B. In substantially the same manner as described above, during engagement and while the heated parts are at their high working temperatures, the coupler 1226 undergoes engagement motion, resulting in plastic deformation of at least a portion of the material in the heated parts. As described above, the engagement motion can be any motion of one or both of the coupler and the structural element relative to the other. While the coupler 1226 is undergoing engagement motion, it is preferable that the coupler 1226 is biased relative to the structural element 1220 in the direction indicated by arrow "12A".

[0124] During the high working temperature, the heated portion of the forming part 1275 of the main body 1228 and the heated portion of the wall 1272 engage with each other, causing at least partial plastic deformation of the heated portion. As described above, the plastic deformation creates a zone of recrystallized metal having a relatively fine-grained microstructure. The surfaces of the walls 1272 and 1276 are at least partially incorporated into the recrystallized zone.

[0125] As shown in Figure 17B, when the coupler 1226 is joined to the structural element 1220, product 1237 is formed. It is understood that the fins 1230 and 1231 have been omitted from Figure 17B for clarity in the illustration.

[0126] It is also understood that one or more of the structural elements 1220 and the coupler body 1228 may include one or more cavities 1242. The cavities 1242 are positioned and sized such that the coupler 1226 is joined to the structural element 1220 and at least a portion of the plastically deformable material can be extruded into the cavities 1242 (Figures 17A and 17B).

[0127] In another alternative embodiment, the coupler 1326 may be joined to the structural element 1320, as schematically shown in Figures 18A to 18C. The coupler 1326 preferably includes a body 1328.

[0128] As can be seen in Figure 18A, in one embodiment, the coupler 1326 includes several fins 1330 or a set of fins 1330 protruding from the body 1328. The lengths of the fins shown in Figure 18A are exaggerated for clarity in the illustration.

[0129] The structural element 1320 includes several sheets 1380 of metal or any other preferred material fixed together to form a frustum cone. The sheets 1380 are partially joined to the couplers 1326 when the couplers 1326 are fixed to the sheets at their respective upper ends 1382.

[0130] Firstly, one or more heating elements 1332 are positioned between the coupler 1326 and the upper end 1382 of the sheet 1380. The coupler 1326 and the upper end 1382 are preferably covered with an inert atmosphere. It is understood that the container for containing the inert atmosphere is omitted from Figures 18A to 18C for clarity in the illustration.

[0131] The heating element is then energized to heat a section of the coupler 1326 (considered to be the heated part of the coupler) to a high working temperature in an inert atmosphere. The heated part includes at least a portion of the fin 1330. It is also preferable that the heating element be positioned to heat a section or portion of the sheet 1380 (which may be considered to be the heated part of the structural element). The heated parts are understood to be heated to a high working temperature to which they can be plastically deformed.

[0132] While the heated portion is at its high working temperature, the heating element 1332 is removed and the coupler 1326 is pressed against the upper end 1382, i.e., in the direction indicated by arrow "13A" in Figure 18C. In substantially the same manner as described above, during engagement and while the heated portion is at its high working temperature, the coupler 1326 preferably undergoes an engagement motion, resulting in plastic deformation of at least a portion of the material in the heated portion. As described above, the engagement motion can be any motion of one or both of the coupler and the structural element relative to the other. While the coupler 1326 is undergoing the engagement motion, it is preferable that the coupler 1326 is biased against the structural element 1320 in the direction indicated by arrow "13A".

[0133] During the high working temperature, the heated portion of the coupler 1326 and the heated portion of the upper end 1382 engage with each other, causing at least partial plastic deformation of the heated portion. As described above, the plastic deformation creates a zone of recrystallized metal having a relatively fine-grained microstructure. The engaged surfaces of the coupler body 1328 and the sheet 1380 are at least partially incorporated into the recrystallized zone.

[0134] As shown in Figure 18C, when the coupler 1326 engages with the structural element 1320, product 1337 is formed. It is understood that the fins have been omitted from Figure 18C for clarity in the illustration.

[0135] It is also understood that one or more of the structural element 1320 and the coupler body 1328 may include one or more inclined surfaces. When the coupler 1326 is joined to the structural element 1320, the inclined surfaces are formed to define one or more cavities from which at least a portion of the plastically deformable material can be extruded (Figures 17A and 17B).

[0136] As can be seen in Figure 19A, structure 1402 includes upper and lower plates 1404, 1406 and several I-beams or pillars positioned between them. For convenience, the I-beams or pillars shown in Figure 19A are identified by reference numerals 1408A, 1408B, and 1408C. It should be understood that the pillars may have any preferred shape and are not necessarily I-beams.

[0137] Several couplers 1426 are shown in Figure 19A, each positioned at the base end of a pillar. Each coupler 1426 preferably includes a body 1428 and a fin 1430 extending from the body 1428. For clarity in the illustration, only one of the couplers is identified by reference numeral in Figure 19A.

[0138] Firstly, the coupler is positioned for (i) heating and (ii) engaging with the adjacent portions of each pillar and plate (Figure 19A). It is understood that the heating elements (not shown) are positioned to heat the heated parts of the coupler and pillar (not shown in Figure 19A), and the heated parts of the upper and lower plates 1404 and 1406, to their respective high working temperatures, which allow the heated parts to be plastically deformable. It is also understood that the heating elements have been omitted from Figure 19A for clarity in the illustration.

[0139] At least the heated area is covered with an inert (non-oxidizing) atmosphere held in place by a container. The inert atmosphere and the container for it are also omitted from Figure 19A for clarity in the illustration.

[0140] Next, the heating element can heat the part to be heated using any suitable technique, such as induction. When the heated portions of the coupler, pillar, and adjacent plate reach their high working temperatures, the coupler undergoes dislocation motion and moves to engage its heated portion with the heated portion of the pillar and the heated portion of the adjacent plate. In one embodiment, upon engagement, the coupler preferably moves relative to the pillar and plate by engagement motion, causing the plastically deformable heated portion to undergo shearing. (Alternatively, the coupler may undergo engagement motion before engagement). As described above, the shearing of the plastically deformable material (metal) results in the recrystallization of at least a portion of the heated portion, providing a zone of recrystallized metal with a microstructure having substantially uniform particle size. The zone of recrystallized metal extends throughout the entire unheated region. The initially engaged surface is at least partially incorporated into the zone of recrystallized material.

[0141] An example of the coupler being engaged with pillar 1408B and lower plate 1406 can be seen in Figure 19B. For convenience, the coupler shown in Figure 19B is identified by 1426A and 1426B. Its fins have been omitted from Figure 19B for clarity.

[0142] In Figure 19B, the heated portions of couplers 1426A, 1426B and pillar 1408B are identified by reference numerals 1434A, 1434B, and 1436A, 1436B, respectively. The heated portions of the lower plate are identified by reference numerals 1437A and 1437B, respectively (Figure 19B).

[0143] As can be seen in Figure 19A, the coupler body is formed to interlock with the pillar 1408B and the lower plate 1406. The body 1428 includes a first portion 1484 and a second portion 1485 that are integrally formed. The first and second portions 1484 and 1485 are formed to engage substantially simultaneously with the pillar and the plate, respectively, and are exposed to fins compressed between the body and the pillar, and also between the body and the plate.

[0144] When engaged, the couplers 1426A and 1426B move preferably relative to the pillar and lower plate while the heated parts are at their high working temperatures. The plastically deformable material in the heated parts is then sheared, resulting in the couplers being joined to the pillar and plate as described above.

[0145] As can be seen in Figure 20, the result of the process described above is that the pillar is joined to the upper and lower plates 1404 and 1406 by couplers. For convenience, the pillar is identified in Figure 20 by reference numerals 1408A, 1408B, and 1408C.

[0146] Figure 21 provides a partial side view of pillar 1408B and longitudinal cross-sectional views of upper and lower plates 1404 and 1406. As can be seen in Figure 21, it is preferable that the couplers are spaced apart from each other when joining pillar 1408B to upper and lower plates 1404 and 1406. For convenience, the coupler that joins pillar 1408B to upper plate 1404 is reference numeral 1426 in Figure 21. u -1,1426 u -2, 1426 u -3, and 1426 u It is identified by -4. Also, the coupler that connects pillar 1408B to lower plate 1406 is reference numeral 1426 in Figure 21. L -1,1426 L -2, 1426 L -3, and 1426 L Identified by -4

[0147] As can be seen in Figure 22A, structure 1502 includes upper and lower plates 1504 and 1506, and several I-beams or pillars positioned between them. For convenience, the I-beams or pillars shown in Figure 22A are identified by reference numerals 1508A, 1508B, and 1508C. It should be understood that the pillars may have any preferred shape and are not necessarily I-beams.

[0148] Similarly, as can be seen in Figure 22A, both plates 1504 and 1506 have a substantially convex profile. The process of joining the pillar to the upper and lower plates is understood to be substantially the same as the process of joining the pillar to the non-curved upper and lower plates described above in relation to Figures 19A to 21.

[0149] Several couplers 1526 are shown in Figure 22A, each positioned at the base end of a pillar. Each coupler 1526 includes a body 1528 and a fin 1530 extending from the body 1528. For clarity in the illustration, only one coupler is identified by reference numeral in Figure 22A.

[0150] Firstly, the coupler is positioned for (i) heating and (ii) engaging with the adjacent portions of each pillar and plate (Figure 22A). It is understood that the heating element (not shown) is positioned to heat the heated parts of the coupler and pillar (not shown in Figure 22A) and the heated parts of the upper and lower plates 1504 and 1506 to a high working temperature at which the heated parts can be plastically deformed. It is also understood that the heating element has been omitted from Figure 22A for clarity in the illustration.

[0151] The heated area is covered by an inert (non-oxidizing) atmosphere held in place by a container. The inert atmosphere and the container for it are also omitted from Figure 22A for clarity.

[0152] Next, the heating element heats the part to be heated using any suitable technique, such as induction. When the heated portion of the coupler, pillar, and adjacent plate is at a high working temperature, the coupler preferably undergoes dislocation motion and moves to engage the heated portion of the coupler with the heated portion of the pillar and the adjacent plate. In one embodiment, upon engagement, the coupler preferably moves in an engaging motion relative to the pillar and plate, causing the plastically deformable heated portion to undergo shearing. (Alternatively, the coupler may undergo an engaging motion before engagement). As described above, due to the shearing of the plastically deformable material (metal), at least a portion of the heated portion is recrystallized, providing a zone of recrystallized metal with a microstructure having substantially uniform particle size. The zone of recrystallized metal extends throughout the entire unheated region. The initially engaged surface is at least partially incorporated into the zone of recrystallized material.

[0153] An example of the coupler being shown in its engaged state with pillar 1508B and lower plate 1506 can be seen in Figure 22B. For convenience, the coupler shown in Figure 22B is identified by reference numerals 1526A and 1526B. Its fins have been omitted from Figure 22B for clarity of the illustration.

[0154] In Figure 22B, the heated portions of couplers 1526A and 1526B and pillar 1508B are identified by reference numerals 1534A, 1534B, and 1536A and 1536B, respectively. The heated portions of the lower plate are identified by reference numerals 1537A and 1537B, respectively (Figure 22B).

[0155] As can be seen in Figure 22A, the coupler body is preferably formed to interlock with the pillar 1508B and the lower plate 1506. The body 1528 includes a first portion 1584 and a second portion 1585 that are integrally formed. The first and second portions 1584 and 1585 are preferably formed to engage substantially simultaneously with the pillar and the plate, respectively, and are exposed to fins between the compressed body and the pillar, and between the body and the plate.

[0156] When engaged, the couplers 1526A, 1526B move relative to the pillars and the lower plate while the heated part is at their elevated operating temperature. The plastically deformable material in the heated part is then sheared, and as a result, the couplers are joined to the pillars and the plate as described above.

[0157] As can be seen in FIG. 23, the result of the aforementioned process is that the pillars are joined by the couplers to the upper and lower plates 1504, 1506. For convenience, the pillars are identified in FIG. 23 by reference numerals 1508A, 1508B, and 1508C.

[0158] In FIG. 24, a partial side view of pillar 1508B and longitudinal cross-sectional views of the upper and lower plates 1504, 1506 are provided. As can be seen in FIG. 24, it is desirable for the couplers to join pillar 1508B to the upper and lower plates 1504, 1506 with the couplers spaced apart from each other. For convenience, the couplers joining pillar 1508B to the upper plate 1504 are identified in FIG. 24 by reference numerals 1526 u -1, 1526 u -2, 1526 u -3, and 1526 u -4. Also, the couplers joining pillar 1508B to the lower plate 1506 are identified in FIG. 24 by reference numerals 1526 L -1, 1526 L -2, 1526 L -3, and 1526 L -4.

[0159] As can be seen in FIG. 25, structure 1602 includes upper and lower plates 1604, 1606 and a pillar 1608 positioned therebetween. FIG. 25 is a longitudinal cross-sectional view of structure 1602 including a side view of pillar 1608. Preferably, the couplers join pillar 1608 to the upper and lower plates 160, 1606.

[0160] As can be seen in Figure 25, the upper and lower plates 1604 and 1606 are parallel in the longitudinal direction and have a substantially convex profile, i.e., parallel to the pillars. It is understood that structure 1602 includes several pillars positioned between the upper and lower plates 1604 and 1606, with pillar 1608 being representative.

[0161] The couplers are positioned with gaps between them, and the pillars 1608 are joined to the upper and lower plates 1604 and 1606 with gaps between them. For convenience, the coupler that joins pillar 1608 to upper plate 1604 is reference numeral 1626 in Figure 25. u -1, 1626 u -2, 1626 u -3, and 1626 u Identified by -4. Also, the coupler that connects pillar 1608 to lower plate 1606 is reference numeral 1626 in Figure 25. L -1, 1626 L -2, 1626 L -3, and 1626 L Identified by -4

[0162] It is understood that the pillar may have any suitable shape and does not necessarily have to be an I-beam. It is also understood that the process of joining the pillar to the upper and lower plates is substantially the same as the process of joining the pillar to the other upper and lower plates described above.

[0163] The coupler is shown in Figure 25 after it has been joined to pillar 1608 and to the upper and lower plates. As described above, due to shearing of the plastically deformable material (metal), at least a portion of the heated area is recrystallized, providing a zone of recrystallized metal with a microstructure having substantially uniform particle size. The zone of recrystallized metal extends throughout the entire unheated area. The initially engaged surface is at least partially incorporated into the zone of recrystallized material.

[0164] From the foregoing, it can be seen that embodiments of the method of this disclosure have the following advantages. 1. This method can be used without requiring a qualified welder. 2. Embodiments of this method can be largely automated, leading to greater confidence in the process and the resulting product.

[0165] 3. The completeness of the finished product can be electronically documented. Those skilled in the art will recognize that this disclosure can take many forms, and that such forms fall within the scope of the claimed disclosure. The scope of the claims should not be limited by the examples and preferred embodiments, but should be given the broadest possible interpretation consistent with the entire description.

Claims

1. It is a method, To provide a pair of structural elements, wherein each of the structural elements includes an end portion, and the end portions of each of the pair of structural elements are positioned opposite each other. To provide at least one coupler, each of which includes a body portion, and the body portion is positioned in close proximity to the end portions of each of the pair of structural elements, To provide an inert atmosphere that covers the coupler and the respective end portions of the pair of structural elements, The coupler heating section of at least one of the couplers is heated to the coupler's high-temperature working temperature, and the structural element heating section of the end portion is heated to the structural element's high-temperature working temperature. To engage the at least one coupler with the inner or outer surface of the end portion of each of the pair of structural elements, the at least one coupler and at least one selected one or both of the pair of structural elements are subjected to displacement motion. The coupler and at least one or more of the pair of structural elements are subjected to an engagement motion in which the coupler and at least one or more of the pair of structural elements move relative to the other. A method comprising biasing the at least one coupler at its end portion to the inner or outer surface of each of the pair of structural elements in order to join the at least one coupler to the end portion of each structural element.

2. To provide a coupler, The method according to claim 1, further comprising providing a plurality of fins positioned on each of the body portions of the at least one coupler for at least partial engagement with the inner surface of the end portions of each of the pair of structural elements.

3. To provide a coupler, The method according to claim 1, further comprising providing a plurality of fins positioned on each of the body portions of the at least one coupler for at least partial engagement with the outer surface of the end portion of each of the pair of structural elements.

4. Heating the coupler heating section of the coupler to the coupler's high-temperature working temperature, and heating the structural element heating section of the end portion to the structural element's high-temperature working temperature, To provide at least one heating element adjacent to the end portion of the at least one coupler and the pair of structural elements, To heat the heated section of the coupler and the heated section of the structural element, energize the at least one heating element, The method according to claim 1, comprising removing at least one of the heating elements.

5. The method according to claim 1, wherein each of the end portions of the pair of structural elements has an inclined surface so that a cavity is formed when the end portions engage, and the heated coupler section is pushed into the cavity while at least one of the dislocation and engagement movements is performed.

6. The method according to claim 1, wherein providing at least one coupler comprises providing at least two couplers.

7. The method according to claim 6, further comprising inserting an intermediate element between the at least two couplers to seal the gap between the at least two couplers.

8. To join the at least one coupler to the end portion of each structural element, biasing the at least one coupler at its end portion to the inner or outer surface of each of the pair of structural elements is: The method according to claim 1, comprising biasing the at least one coupler at its end portion to both the inner and outer surfaces of each of the pair of structural elements in order to join the at least one coupler to the end portion of each structural element.

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