Reinforced structure having continuous fiber reinforced elements and method for making the same

Abstract

A reinforced structure is disclosed, the structure being comprised of reinforcing elements having continuous fibers embedded in a matrix material, the reinforcing elements interlocking within the matrix material to form the desired shape of the reinforced structure.

Description

[Technical Field]

[0001] The present invention relates to a thermoplastic structure having a profile reinforced with continuous fiber reinforcing filaments. [Background technology]

[0002] The use of high modulus fiber composites, for example using carbon, glass, aramid, ceramic, or basalt fibers, as well as matrices made of, for example, thermoset or thermoplastic elastomers, carbon, graphite, or ceramic, and related materials, requires the use of appropriate constructions for power transmission suited to the material. Material-related means that the anisotropy of the material with respect to various mechanical properties in and across the fiber direction is used in a targeted manner.

[0003] Connecting rods made of fiber composite materials for power transmission are used, in particular, for guidance and mechanical storage, for support, for bracing, or for connections. Connecting rods made of fiber composite materials have been known for many years. Such connecting rods are preferably, but not exclusively, used in aircraft or spacecraft. For example, connecting rods in aircraft and spacecraft, such as aircraft, rotorcraft, airships, unmanned aerial systems, rockets, or satellites, are loaded primarily axially by both compressive and tensile forces.

[0004] As the demand for weight reduction and cost reduction increases, the possibilities of known designs for struts having tubular bodies made of thermosetting fiber composite materials become limited.

[0005] Thermoplastic structures can be employed for connecting rods or tension-compression struts, where struts with large external dimensions can be realized within a given installation space.

[0006] When using fiber-reinforced pipes and profiles on a thermosetting matrix basis, there is often a fundamental problem of keeping the damage of the laminate due to impact as small as possible. To address problematic impact damage, cost-intensive modified resin systems are often used. In contrast, the use of thermosetting matrix materials has a positive effect on impact behavior. Summary of the Invention [Problem to be solved by the invention]

[0007] The production costs for fiber-reinforced profiles are very high, and yet the profile geometries are very limited. Profiles made with a thermosetting matrix cannot be reshaped after completion, and thermosetting materials have poorer impact behavior compared to thermoplastics. Furthermore, there are only a limited number of thermosetting materials with FST (fire smoke and toxicity) approval that can be used in certain environments, including the aviation sector. [Means for solving the problem]

[0008] This technology can provide thermoplastic structures with profiles reinforced with continuous fiber reinforcing filaments that can form the substrate for tension-compression struts and other support structures.

[0009] An embodiment of the present disclosure includes a reinforced structure having a cross-sectional profile having continuous fiber reinforced filaments and a first matrix material, wherein the continuous fiber reinforced filaments are embedded in the first matrix material along a longitudinal axis of the fiber reinforced element, thereby forming the continuous fiber reinforced element.

[0010] In some embodiments, the reinforcement structure further comprises a second matrix material, wherein the continuous fiber reinforcing elements are embedded in the second matrix material, thereby forming the cross-sectional profile.

[0011] In one variation, the first matrix material and the second matrix material are different materials. In another variation, the first matrix material and the second matrix material are the same material.

[0012] In one aspect, the cross-sectional profile of the reinforced structure can have a shape selected from the group consisting of a triangle, a circle, a rectangle, and a T. In an implementation, the cross-sectional profile has an outer shape surrounding a hollow area with a shape selected from the group consisting of a triangle, a circle, and a rectangle.

[0013] In another embodiment, the cross-sectional profile of the continuous fiber reinforcing elements may be a shape selected from the group consisting of triangle, circle, rectangle, trapezoid, and hexagon. In a particular embodiment, the continuous fiber reinforcing elements have a circular cross-sectional shape with a diameter of 0.4 mm or greater.

[0014] In yet another aspect, the reinforcing structure has continuous fiber reinforcing elements having an exterior shape for interlocking or intermeshing with other continuous fiber reinforcing elements.

[0015] The reinforced structure may have a fiber volume fraction of continuous fiber reinforcing elements of at least 35%.

[0016] In certain embodiments, the reinforcing structure has a tubular cross-sectional profile. The continuous fiber reinforcing elements can have a cross-sectional shape selected from the group consisting of triangular, circular, rectangular, trapezoidal, and hexagonal. In one implementation, the continuous fiber reinforcing elements have a circular cross-sectional shape with a diameter of 0.4 mm or greater. In any of the tubular reinforcing structures, the continuous fiber reinforcing elements can have a fiber volume fraction of at least 35%.

[0017] In one embodiment of a reinforced structure having a tubular cross-sectional profile, the fiber reinforcing elements can have a cross-sectional shape that is an arc segment of the tubular cross-sectional diameter (D). The fiber reinforcing elements form the tubular configuration of the reinforced structure. A winding layer of unidirectional reinforcing tape can be wrapped around and over the outer surface of the arc segment tubular configuration.

[0018] In another embodiment of a reinforced structure having a tubular cross-sectional profile, the fiber reinforcing elements can have a cross-sectional shape that is an arc segment of the diameter (D) of the tubular cross section. The arc segments form the tubular configuration of the reinforced structure with gaps between the edges of the fiber reinforcing elements. A matrix material can surround the outer surface of the tubular configuration and fill the gaps. A winding layer of unidirectional reinforcing thermoplastic tape can be wrapped around and over the outer surface of the matrix material.

[0019] An embodiment of the present disclosure is a method of forming a reinforced structure having a tubular cross-sectional profile, comprising forming at least two arc segments of a tubular cross-sectional diameter (D) and forming a tubular configuration of the reinforced structure having the at least two arc segments. The method can include wrapping a layer around and over an outer surface of the formed tubular configuration.

[0020] In one aspect of the method of forming a reinforced structure, adjacent arc segments are attached to one another with their edges contacting one another at contact locations. In certain implementations, the arc segments are interlocking elements for attachment to one another.

[0021] In another aspect of the method of forming a reinforced structure, gaps exist between the edges of adjacent arc segments forming a tubular configuration, and the method includes applying a matrix material onto the outer surfaces of the arc segments, the matrix material filling the gaps.

[0022] In any embodiment of the method for forming a reinforced structure having a tubular configuration, the layer wound onto the outer surface may be a unidirectionally reinforced thermoplastic tape. Alternatively, the layer is a unidirectionally reinforced thermosetting tape. In any of these embodiments, the method includes winding the layer under pretension, at a predetermined winding feed width, and under rotation, and heating the layer to melt the matrix of the tape and the tubular configuration to aid in adhesion. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 shows a cross-sectional profile of a fiber reinforced element having a circular cross-section. [Figure 2] FIG. 1 shows the cross-sectional profile of a fiber reinforced element having a rectangular cross section. [Figure 3] FIG. 1 shows a cross section of a woven fiber reinforcement element. [Figure 4A] 1A-1C show examples of cross-sectional shapes of structural elements constructed from fiber-reinforced elements. [Figure 4B] 1A-1C show examples of cross-sectional shapes of structural elements constructed from fiber-reinforced elements. [Figure 4C] 1A-1C show examples of cross-sectional shapes of structural elements constructed from fiber-reinforced elements. [Figure 4D] 1A-1C show examples of cross-sectional shapes of structural elements constructed from fiber-reinforced elements. [Figure 5] FIG. 10 illustrates a cross-sectional profile of interlocking continuous fiber reinforcing elements. [Figure 6] 6 shows a detail of the cross-sectional shape of the structural tubular element having at least two interlocking fiber reinforcement elements of FIG. 5. FIG. [Figure 7] FIG. 10 illustrates a cross section of a fiber reinforced element having an arc segment profile. [Figure 8] FIG. 8 shows a cross-sectional profile of a first reinforced tubular structure using the elements of FIG. 7 in combination with a reinforcing layer. [Figure 9] FIG. 8 shows a cross-sectional profile of a second reinforced tubular structure using the elements of FIG. 7 in combination with a reinforcing layer. [Figure 10] 10A and 10B show a mechanism for applying a ring-shaped layer to secure a plurality of fiber reinforcing elements having an arc segment profile to achieve a reinforced tubular structure, respectively. DETAILED DESCRIPTION OF THE INVENTION

[0024] The terms "comprising" and "comprises" in this disclosure can mean "including," "includes," or "having," or can have the meaning commonly given to the terms "comprising" and "comprises" in U.S. patent law. The term "consisting essentially of," when used in the claims, has the meaning ascribed to that term in U.S. patent law. Other aspects of the invention are described in or will be obvious from the following disclosure (and are within the scope of the invention).

[0025] The terms "thread," "fiber," "filament," and "yarn" are used interchangeably in the following description. As used herein, "thread," "fiber," "filament," and "yarn" can refer to monofilament, multifilament yarn, twisted yarn, multifilament tow, textured yarn, braided yarn, coated yarn, bicomponent yarn, as well as yarns made of any material known to those skilled in the art. Yarns can be made of carbon, fiberglass, cotton, aramid, polyamide, polyester, metal, polyethylene, and / or other materials that exhibit desired physical, thermal, chemical, or other properties.

[0026] The terms "embedded" and "encapsulated" are used interchangeably.

[0027] Fiber-reinforced structures according to the present disclosure can be characterized by a profile cross-section filled with continuous fiber reinforcing elements for the purpose of improving mechanical properties such as strength and stiffness. In particular applications, the fiber-reinforced structures can provide a cross-sectional profile for support members such as connecting rods or tension-compression struts, where struts with the largest possible external dimensions can be realized within a given installation space.

[0028] FIG. 1 shows a cross-sectional profile of a fiber reinforced element 100. While a circular cross-sectional shape is shown, other cross-sectional shapes are contemplated, including but not limited to rectangular, triangular, trapezoidal, hexagonal, etc. The continuous fiber reinforced element can have a fiber volume fraction of at least 35%. The fiber reinforced element includes continuous fiber reinforced filaments embedded in a matrix 104, which are continuous throughout the length of the fiber reinforced element 100 and distributed throughout the cross-sectional profile. The continuous fiber reinforced element 100 can have a diameter of at least 0.40 mm.

[0029] The fiber reinforcement filaments are composed of materials including, but not limited to, woven fabrics, carbon, glass, basalt, plastic, ceramic, aramid, polyester, nylon, and rayon. The matrix materials include, but are not limited to, polypropylene (PP), polyamide (PA), acrylonitrile butadiene styrene (ABS), polyethyleneimine (PEI), polyphthalamide (PPA), polyphenylene sulfide (PPS), polyaryletherketone (PAEK), polyetherketoneketone (PEKK), or polyetheretherketone (PEEK). The woven fabrics include single fiber filaments or rovings made of glass, carbon, basalt, ceramic, and / or plastic to form woven, braided, knitted, and laid fabrics.

[0030] Thermoplastic continuous fiber reinforcing elements can be produced, for example, by a pultrusion process in which continuous fiber reinforcing filaments are fed.

[0031] 2 shows an overall continuously fiber reinforced profile of a fiber reinforced element 200 having a rectangular cross section and having fiber reinforcement filaments 205 embedded in a matrix material 204. The dimensions of the fiber reinforced element may be 12.7 mm (0.5 inches) wide by 0.2 mm (0.008 inches) thick or greater.

[0032] 3 shows a cross-section of a woven fiber reinforcement element 300 comprising a matrix material 304 and woven reinforcing filaments 307 interwoven with fibers 310. By using a semi-finished woven product, additional reinforcement can be achieved transverse to the longitudinal axis of the element 300 using fibers 310. Element 300 having a rectangular cross-sectional shape is shown for convenience, as any shape is contemplated. While woven reinforcing filaments 307 having an oval cross-section are shown, other shapes are also contemplated. Furthermore, the shape of woven reinforcing filaments 307 can change when subjected to a compressive force.

[0033] Woven fiber reinforcement elements 300 may be combined to form reinforced structures having any desired cross-sectional profile described herein.

[0034] Figures 4A-4D show non-limiting examples of cross-sectional shapes of structural elements that may be constructed from the fiber-reinforced elements described hereinabove. Circular fiber-reinforced elements are shown for convenience, but other shapes are contemplated. The cross-sectional shapes of Figures 4A-4C are the outer shapes, and this outer shape is the periphery of the shape. That is, the periphery of the structural element surrounds the hollow area H.

[0035] FIG. 4A shows a circular structural element 400 constructed from fiber reinforced elements 410 embedded in a matrix material 430. The matrix material 430 discussed above can be the same or different from the matrix material in the fiber reinforced element 410. FIG. 4B shows a rectangular structural element 404 constructed from fiber reinforced elements 410 embedded in a matrix material 430. FIG. 4C shows a triangular structural element 404 constructed from fiber reinforced elements 410 embedded in a matrix material 430. FIG. 4D shows a T-shaped structural element 408 constructed from fiber reinforced elements 410 embedded in a matrix material 430. FIGS. 4A-D show examples of structural element shapes that can be formed from fiber reinforced elements. Other structural element shapes are contemplated.

[0036] 5 shows a cross-sectional view of an interlocking continuous fiber reinforced element 500 with a continuous fiber reinforced filament 510. The fiber reinforced filament may be similar to that described above in connection with FIG. 1. The fiber reinforced filament may be unidirectional along the length of the element 500 and may be embedded in a matrix material 540.

[0037] The continuous fiber reinforcement elements 500 can interlock or interlock with one another as a result of the functional exterior shape 502. Interlocking elements 500 illustrate one possible interlocking functional exterior shape 502 having a head portion 504 and a tail portion 506. Head portion 504 is shaped to interlock with or nest within tail portion 506, as shown in FIG. 6. Other interlocking functional exterior shapes known to those skilled in the art are also contemplated without departing from the inventive concepts of the techniques disclosed herein.

[0038] 6 shows one implementation of a reinforced structure 600 having at least two interlocking fiber reinforcement elements 500. The fiber reinforced structure 600 can have any desired geometry that can be formed by interlocking at least two fiber reinforcement elements 500 within a matrix material 640 to form a desired geometry 602, which may be the same as or different from the matrix material 540 of the interlocking fiber reinforcement elements.

[0039] 7 shows a cross section of another implementation of a fiber reinforced element 702 comprised of a fiber reinforced filament 705 embedded in a matrix material 706. The fiber reinforced element 702 may be an arc segment of a circle. The thickness W of the element 702 may be 1 mm, although any desired thickness may be formed.

[0040] FIG. 8 shows a cross section of a reinforced tubular structure 801 formed from fiber reinforcement elements 802, 804, 806, and 808. Each of the fiber reinforcement elements 802, 804, 806, and 808 may be an arc segment of a circle formed as discussed above in connection with FIG. 7. The elements 802, 804, 806, and 808 form a circle having a diameter D, which may be surrounded and contacted by a winding layer 803 around the outside of the elements 802, 804, 806, and 808. As shown, each fiber reinforcement element 802, 804, 806, and 808 is a quarter (90-degree) arc segment. Because there may be more than one fiber reinforcement element, the illustration in FIG. 8 is for illustrative purposes only. Furthermore, the elements may be of any arc angle, and the arc angles are not necessarily equal in magnitude.

[0041] Elements 802, 804, 806, 808 may be assembled at contact location 810 to form a tubular structure. Elements 802, 804, 806, 808 may be attached to one another at contact location 810 by any known mechanism known to those skilled in the art. Alternatively, the arc segments may be pre-fixed onto the mandrel using attachment points for adhesive or the like on the inner surfaces of the arc segments. Additionally, elements 802, 804, 806, 808 may be attached to one another by being interlocking elements as discussed above in connection with FIG. 5. Winding layer 803 may be formed using unidirectional reinforced thermoplastic tape wrapped around the formed tubular structure, as described below.

[0042] FIG. 9 shows a cross section of a reinforced tubular structure 901 formed from fiber reinforcement elements 902, 904, 906, and 908. Each of the fiber reinforcement elements 902, 904, 906, and 908 may be an arc segment of a circle formed as discussed above in connection with FIG. 7. The elements 902, 904, 906, and 908 form a circle with gaps 910 between the arc segments. A matrix material 914 may fill the gaps 910 and may surround and contact the elements on the outside, which may be achieved by a coextrusion process or other known means. A winding layer 903 may surround and contact the outside of the matrix material 914. The winding layer 903 may be formed using a unidirectional thermoplastic tape or a unidirectional thermoset tape wrapped around the formed tubular structure, as described below. Because there may be more than one fiber reinforcement element, the illustration in FIG. 9 is convenient for explanation. Furthermore, these elements may be of any arc angle magnitude, and the arc angles do not necessarily have to be of equal magnitude.

[0043] FIG. 10A illustrates the first process step, in which an arc segment element 1002, which may be arc segment elements 802, 804, 806, 808, is positioned on a mandrel 1007.

[0044] FIG. 10B illustrates a second process step in which an arc segment element 1002 positioned on a mandrel 1007 is reinforced with a winding layer 1003 made of unidirectionally reinforced thermoplastic tape 1012. The winding layer 1003 is shown as a hoop winding produced, for example, by thermoplastic winding, in which a heat source 1008 melts the base material of the tape 1012, and the layer is wound under pretension 1010, a predetermined winding feed width 1011, and rotation 1009. The hoop winding secures and strengthens the arc segment element within the tubular body. The winding layer may be a cross-wound layer. If a cross-wound layer is used, the winding layer deviates from the hoop winding at an angle of approximately 90° relative to the longitudinal axis of the arc segment. For example, the cross-wound layer of tape may be wound at ±45° relative to the longitudinal axis of the arc segment. Other winding angles are contemplated. The winding layer may be one layer or two or more layers.

[0045] The winding process can be discontinuous or continuous. In the case of continuous winding, the arc segment elements can be pre-fixed by co-extrusion. Alternatively, the arc segments of the tubular structure can be drawn directly without the intermediate step of fabricating the fiber-reinforced elements. Furthermore, in contrast to discontinuous winding, the winder rotates, not the components. In the case of continuous winding, pre-fixing can be sufficient to eliminate the mandrel.

[0046] Other implementations are within the scope of the following claims. <Additional Notes> [Form 1] A reinforced structure having a cross-sectional profile (400, 404, 406, 408, 600, 801, 901), Continuous fiber reinforced filaments (105, 205, 307, 510, 705); The first base material (104, 204, 304, 540, 706) Equipped with 10. A reinforced structure, wherein the continuous fiber reinforced filaments are embedded in the first matrix material along a longitudinal axis of the fiber reinforced element, thereby forming a continuous fiber reinforced element (100, 200, 300, 500, 702). [Form 2] a second base material (430, 640); 2. The reinforced structure of claim 1, wherein the continuous fiber reinforcing elements are embedded in the second matrix material, thereby forming the cross-sectional profile. [Form 3] 3. The reinforced structure of claim 2, wherein the first matrix material and the second matrix material are different materials. [Form 4] 3. The reinforced structure of claim 2, wherein the first matrix material and the second matrix material are the same material. [Form 5] 5. The reinforced structure of any one of aspects 1 to 4, wherein the cross-sectional profile has a shape selected from the group consisting of a triangle, a circle, a rectangle, and a T-shape. [Form 6] 6. The reinforced structure of claim 5, wherein the cross-sectional profile has an outer shape enclosing a hollow area having a shape selected from the group consisting of a triangle, a circle, and a rectangle. [Form 7] 7. The reinforced structure of any one of claims 1 to 6, wherein the continuous fiber reinforcing elements have a cross-sectional shape selected from the group consisting of triangular, circular, rectangular, trapezoidal, and hexagonal. [Form 8] 8. The reinforced structure of any one of the preceding aspects, wherein the continuous fiber reinforcing elements have an outer shape for interlocking or interlocking with other continuous fiber reinforcing elements. [Form 9] 9. The reinforced structure of any one of the preceding claims, wherein the fiber reinforcement elements are interlocked with one another and embedded in a second matrix material. [Form 10] 10. The reinforced structure of any one of claims 7 or 9, wherein the continuous fiber reinforcing elements have a circular cross-sectional shape with a diameter of 0.4 mm or more. [Form 11] 11. The reinforced structure of any one of the preceding claims, wherein the continuous fiber reinforcement elements have a fiber volume fraction of at least 35%. [Form 12] 2. The reinforced structure of claim 1, wherein the cross-sectional profile is tubular. [Form 13] 13. The reinforced structure of claim 12, wherein the continuous fiber reinforcing elements have a cross-sectional shape selected from the group consisting of triangular, circular, rectangular, trapezoidal, and hexagonal. [Form 14] 14. The reinforced structure of claim 13, wherein the continuous fiber reinforcing elements have a circular cross-sectional shape with a diameter of 0.4 mm or more. [Form 15] 15. The reinforced structure of any one of claims 12 to 14, wherein the continuous fiber reinforcing elements have a fiber volume fraction of at least 35%. [Form 16] 16. The reinforced structure of any one of aspects 12 to 15, wherein the fiber reinforcement elements (702, 802, 804, 806, 808, 902, 904, 906, 908) have a cross-sectional shape that is an arc segment of a tubular cross-sectional diameter (D). [Form 17] fiber reinforcement elements (802, 804, 806, 808) forming the tubular configuration of the reinforced structure; a winding layer (803) of unidirectional reinforcing tape wrapped around and on the outer surface of said tubular structure; 17. The reinforced structure of claim 16, comprising: [Form 18] fiber reinforcement elements (902, 904, 906, 908) forming a tubular configuration of the reinforced structure, with gaps (910) between edges of the fiber reinforcement elements; a second matrix material (914) surrounding the outer surface of the tubular structure and filling the gap; a winding layer (903) of unidirectional reinforced thermoplastic tape wrapped around and over the outer surface of the second matrix material; 17. The reinforced structure of claim 16, comprising: [Form 19] 13. A method of forming a reinforced structure having a tubular cross-sectional profile according to claim 12, comprising: forming at least two arc segments of diameter (D) of said tubular cross section; forming a tubular configuration of the reinforced structure having the at least two arc segments; wrapping a layer around and over an outer surface of the formed tubular structure; A method comprising: [Form 20] 20. The method of claim 19, wherein the edges of adjacent arc segments contact and are attached to one another at contact locations. [Form 21] 20. The method of claim 19, wherein the arc segments are interlocking elements for attachment to one another. [Form 22] a gap exists between edges of adjacent arc segments forming the tubular configuration; applying a matrix material onto the outer surface of the arc segment, the matrix material filling the gap; 20. A method for forming a reinforced structure according to claim 19, comprising: [Form 23] 23. The method of forming a reinforced structure of any one of aspects 19 to 22, wherein the winding layer is a unidirectional reinforced thermoplastic tape. [Form 24] 23. The method of forming a reinforced structure of any one of aspects 19 to 22, wherein the winding layer is a unidirectional reinforced thermoset tape. [Form 25] winding the winding layer under pretension, at a predetermined winding feed width, and under rotation; heating the winding layers to melt the tape matrix and heat the tubular structure; 25. A method of forming a reinforced structure according to any one of claims 23 to 24, comprising:

Claims

1. A reinforced structure having a cross-sectional profile (400, 404, 406, 408, 600, 801, 901), continuous fiber reinforced filaments (105, 205, 307, 510, 705); a first base material (104, 204, 304, 540, 706); Equipped with the continuous fiber reinforced filaments are embedded in the first matrix material along a longitudinal axis of the continuous fiber reinforced element, thereby forming a continuous fiber reinforced element (100, 200, 300, 500, 702); the continuous fiber reinforcing elements (702, 802, 804, 806, 808, 902, 904, 906, 908) have a cross-sectional shape that is an arc segment of a tubular cross-sectional diameter (D); the continuous fiber reinforcing elements (802, 804, 806, 808) form a tubular configuration of the reinforced structure; A reinforced structure, characterized in that a wound layer (803) of unidirectional reinforcing tape is wound around and on the outer surface of said tubular structure.

2. a second base material (430, 640); The reinforced structure of claim 1 , wherein said continuous fiber reinforcing elements are embedded in said second matrix material, thereby forming said cross-sectional profile.

3. The reinforced structure of claim 2 , wherein the first matrix material and the second matrix material are different materials.

4. The reinforced structure of claim 2 , wherein the first matrix material and the second matrix material are the same material.

5. 5. A reinforced structure according to any one of claims 1 to 4, wherein the continuous fibre reinforcing elements have an outer shape for interlocking or intermeshing with other continuous fibre reinforcing elements.

6. 6. The reinforced structure of claim 1, wherein the continuous fiber reinforcing elements are interlocked with one another and embedded in a second matrix material.

7. The reinforced structure of claim 1 , wherein the continuous fiber reinforcing elements have a cross-sectional shape selected from the group consisting of triangular, circular, rectangular, trapezoidal, and hexagonal.

8. 8. The reinforced structure of claim 7, wherein the continuous fiber reinforcing elements have a circular cross-sectional shape with a diameter of 0.4 mm or greater.

9. 9. A reinforced structure according to any one of claims 7 to 8, wherein the continuous fibre reinforcing elements have a fibre volume fraction of at least 35%.

10. continuous fiber reinforcing elements (902, 904, 906, 908) forming a tubular configuration of the reinforced structure with gaps (910) between edges of the continuous fiber reinforcing elements; a second matrix material (914) surrounding the outer surface of the tubular structure and filling the gap; a winding layer (903) of unidirectional reinforced thermoplastic tape wrapped around and over the outer surface of said second matrix material; The reinforced structure of claim 1 , comprising:

11. 10. A method of forming a reinforced structure having a tubular cross-sectional profile according to claim 1, comprising: forming at least two arc segments of diameter (D) of said tubular cross section; forming a tubular configuration of the reinforced structure having the at least two arc segments; winding a winding layer around and over an outer surface of the formed tubular structure, the winding layer being a unidirectionally reinforced thermoplastic tape or a unidirectionally reinforced thermoset tape; A method comprising:

12. The method of forming a reinforced structure of claim 11 , wherein edges of adjacent arc segments contact and are attached to one another at contact locations.

13. 12. The method of forming a reinforced structure of claim 11, wherein said arc segments are interlocking elements for attachment to one another.

14. a gap exists between edges of adjacent arc segments forming the tubular configuration; applying a matrix material onto the outer surface of the arc segment, the matrix material filling the gap; 12. A method of forming the reinforced structure of claim 11, comprising:

15. winding the winding layer under pretension, at a predetermined winding feed width, and under rotation; heating the winding layer to melt the matrix of the unidirectionally reinforced thermoplastic tape or the unidirectionally reinforced thermosetting tape and to heat the tubular structure; 12. A method of forming the reinforced structure of claim 11, comprising:

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