Composite component

Abstract

A composite component (102, 202) adapted to resist bending about a bending axis (122, 210) during use is provided. The composite component includes a composite material formed from a plurality of composite plies having a polymer and reinforcing fibers. The plurality of composite plies are arranged in such a manner that: a first set of composite plies (308, 408) is arranged in a substantially anisotropic layup manner in which the reinforcing fibers are oriented substantially perpendicular to the bending axis; a second set of composite plies (310, 410) is arranged in a substantially anisotropic layup, wherein the reinforcing fibers are oriented substantially perpendicular to the bending axis; and an intermediate set of composite plies (312, 412) is arranged in a substantially quasi-isotropic layup and disposed between the first set of composite plies and the second set of composite plies.

Description

[0001] The present invention relates to a composite component, such as an implantable medical device or a carrier. The present invention also relates to a method of manufacturing a composite component. Background Art

[0002] Composite materials comprising polymers and reinforcing fibers are known. For example, carbon fibers have been used as reinforcing fibers in various polymer composite materials. Such composite materials can be used in a variety of applications, including for example the manufacture of medical devices. For example, such composite materials can be used to manufacture implantable devices such as orthopedic implants.

[0003] Composite materials have advantages over metallic materials because composite materials provide improved flexibility while maintaining the strength required to carry loads. In addition, it is known that implantable polymer composite components are less likely to cause bone degradation in patients.

[0004] A fracture fixation plate (also known as a bone plate or trauma plate) can be used in surgery to hold bone fragments together and realign the bone and bone fragments. A fracture fixation plate typically includes preformed screw holes for receiving fixation screws that attach the plate to the bone.

[0005] Fracture fixation plates are typically formed from surgical grade stainless steel or titanium. More recently, fiber reinforced composite materials such as carbon reinforced polyetheretherketone (PEEK) have been used to form fracture fixation plates. One way to form such composite components is by placing composite tapes (or plies) of carbon fibers having different orientations in the X-Y direction in a mold in the Z direction. The resulting laminate can be compressed under heat and pressure to form a semi-finished composite component - a blank. Typically, the plies are arranged at different angles to provide a balanced, symmetric composite material that has a substantially uniform flexural stiffness in all directions, i.e., a quasi-isotropic configuration. Additional technical features such as holes for screws, Kirschner wires or sutures can then be machined in the blank to form the finished plate. The axes of the screw holes are typically parallel to the Z direction but not more than ±45 degrees with respect to the Z direction. Summary of the Invention

[0006] In one aspect, there is provided a composite component adapted to resist bending about a bending axis during use. The composite component comprises a composite material formed from a plurality of composite plies having a polymer and reinforcing fibers. The plurality of composite plies are arranged as follows:

[0007] · A first set of composite plies is arranged in a substantially anisotropic ply stack where the reinforcing fibers are substantially perpendicular to the bending axis,

[0008] · A second set of composite plies is arranged in a substantially anisotropic ply stack where the reinforcing fibers are substantially perpendicular to the bending axis, and

[0009] · The intermediate group of composite plies is arranged in a substantially quasi-isotropic layup pattern and is disposed between the first group of composite plies and the second group of composite plies.

[0010] Advantageously, providing anisotropic layups for the first and second groups of composite plies will increase the flexural stiffness of the composite component. In particular, by positioning the first and second groups of composite plies on either side of the intermediate group, the first and second groups of composite plies will experience higher tensions (and compressions) during bending of the composite component, and the anisotropic layups of the first and second groups will provide improved flexural stiffness compared to other layups. The increased flexural stiffness may be desirable, or such an arrangement may allow for the use of fewer composite plies, thereby allowing the composite component to be thinner and lighter for a given flexural stiffness. At the same time, the quasi-isotropic configuration of the intermediate group provides torsional and shear stiffness to the composite component. The combination of the outwardly positioned anisotropic composites (the first and second groups of composite plies) and the intermediate quasi-isotropic composite (the intermediate group of composite plies) provides a composite component with good flexural stiffness while maintaining the torsional stiffness and other properties provided by the quasi-isotropic layup of the intermediate group of composite plies.

[0011] The composite component may also include one or more screw holes that extend through the composite component for attaching the component using screws in use. The one or more screw holes may be threaded. The one or more screw holes may be tapered.

[0012] In one example, in use, the screw head of the screw abuts against the tapered surface of one or more tapered screw holes. The tapered screw holes may have a larger diameter at one surface (e.g., the top surface) of the composite component than at the opposite surface (e.g., the bottom surface) of the composite component. Tightening the screw head against the tapered screw hole will generate circumferential strain and circumferential stress around the screw hole. Due to the taper of the screw hole, the circumferential strain (and thus the circumferential stress) will be greater towards the smaller diameter side of the screw hole than towards the larger diameter side. This is because the screw head will produce a substantially uniform displacement through the tapered screw hole, and this generates higher strain where the screw hole is smaller.

[0013] In this example, the plurality of composite plies may be arranged such that the intermediate group of composite plies is offset towards the side with the smaller diameter of the tapered screw hole (e.g., towards the bottom surface of the composite component). Thus, the higher circumferential strain and circumferential stress generated by the screw head are borne by the quasi-isotropic arrangement of the intermediate group of composite plies, which is more fracture-resistant than the anisotropic configurations of the first and second groups of composite plies.

[0014] The composite component may include a top surface and a bottom surface. A first set of composite laminae may be disposed at or near the top surface. A second set of composite laminae may be disposed at or near the bottom surface. Providing the first and second sets at the top and bottom surfaces will improve the flexural stiffness because the anisotropic configuration of the first and second sets provides a higher flexural stiffness than a quasi-isotropic set of composite laminae.

[0015] In an example, an intermediate set of composite laminae may be centered on a midplane between the top surface and the bottom surface.

[0016] In other examples, the intermediate set of composite laminae may be offset from the midplane between the top surface and the bottom surface. In an example, the intermediate set of composite laminae may be offset toward the bottom surface. Thus, the intermediate set of composite laminae may be positioned within the thickness of the composite component to align with the region of higher circumferential strain and circumferential stress generated by the screw head in the tapered screw hole of the composite component, as described above.

[0017] In an example, each composite lamina includes a plurality of unidirectional reinforcing fibers. That is, each composite lamina includes a plurality of reinforcing fibers arranged substantially parallel to each other. Each composite lamina may include some reinforcing fibers arranged in a non-parallel manner, such as to hold the other reinforcing laminae together, but primarily the reinforcing laminae are parallel and unidirectional.

[0018] In an example, each of the first set of composite laminae and the second set of composite laminae includes at least two composite laminae, such as at least three composite laminae, such as at least four composite laminae, such as at least five composite laminae.

[0019] In an example, the intermediate set of composite laminae includes at least five composite laminae, such as at least seven composite laminae, such as at least eight composite laminae.

[0020] In an example, the polymer of the composite material includes polyaryletherketone. In an example, the reinforcing fibers of the composite material include carbon reinforcing fibers.

[0021] In an example, the composite component is elongated along a longitudinal axis that is substantially perpendicular to the bending axis.

[0022] In an example, the composite component is an implantable medical device.

[0023] In an example, the composite component is a bracket, such as a bracket for carrying a tool such as an aerospace carrier, an aircraft, a road carrier, or a rail carrier.

[0024] In an example, the composite component is planar. In other examples, the composite component is non-planar. The composite component may be molded.

[0025] In a second aspect, a composite component is provided that includes a composite material formed from a plurality of composite plies including a polymer and reinforcing fibers. The plurality of composite plies are disposed between a top surface and a bottom surface, and a tapered screw hole extends through the composite component, the tapered screw hole having a smaller diameter at the bottom surface than at the top surface. The plurality of composite plies are arranged such that:

[0026] · A first set of composite plies is disposed at or near the top surface,

[0027] · A second set of composite plies is disposed at or near the bottom surface, and

[0028] · An intermediate set of composite plies is disposed between the first set of composite plies and the second set of composite plies.

[0029] The intermediate set of composite plies includes a quasi-isotropic layup. The intermediate set of composite plies is offset from an intermediate plane between the top surface and the bottom surface toward the bottom surface.

[0030] Tightening the screw head will generate circumferential strain and circumferential stress around the screw hole. Due to the taper of the tapered screw hole, the circumferential strain (and thus the circumferential stress) will be greater toward the smaller diameter side of the screw hole (i.e., the bottom surface) than toward the larger diameter side9, i.e., the top surface). This is because the screw head will produce a substantially uniform displacement through the tapered screw hole, and this produces higher strain where the screw hole is smaller.

[0031] Advantageously, the intermediate set of composite plies is offset toward the smaller diameter side of the tapered screw hole (i.e., toward the bottom surface). The quasi-isotropic configuration of the intermediate set of composite plies is better able to withstand the larger circumferential strain / stress, and thus this offset can improve the performance of the composite component.

[0032] In an example, the intermediate set of composite plies includes a symmetric layup.

[0033] In an example, the first set of composite plies includes a substantially anisotropic layup, such as a unidirectional layup. In an example, the second set of composite plies includes a substantially anisotropic layup, such as a unidirectional layup. In an example, during use, the composite component is subjected to bending about a bending axis. In such examples, the first set of composite plies and / or the second set of composite plies can be oriented such that the reinforcing fibers are substantially perpendicular to the bending axis. In this way, the first set of composite plies and the second set of composite plies provide improved flexural stiffness.

[0034] In an example, each composite ply includes a plurality of unidirectional reinforcing fibers. That is, each composite ply includes a plurality of reinforcing fibers arranged substantially parallel to each other. Each composite ply may include some reinforcing fibers arranged in a non-parallel manner, such as to hold other reinforcing plies together, but predominantly the reinforcing plies are parallel and unidirectional.

[0035] In an example, each of a first set of composite plies and a second set of composite plies includes at least two composite plies, such as at least three composite plies, such as at least four composite plies, such as at least five composite plies.

[0036] In an example, an intermediate set of composite plies includes at least five composite plies, such as at least seven composite plies, such as at least eight composite plies.

[0037] In an example, the polymer of the composite material includes polyaryletherketone. In an example, the reinforcing fibers of the composite material include carbon reinforcing fibers.

[0038] In an example, the composite component is elongated along a longitudinal axis that is substantially perpendicular to the bending axis.

[0039] In an example, the composite component is an implantable medical device.

[0040] In an example, the composite component is a bracket, such as a bracket for carrying a tool such as an aerospace carrier, an aircraft, a road vehicle, or a rail vehicle.

[0041] In an example, the composite component is planar. In other examples, the composite component is non-planar. The composite component may be molded.

[0042] In a third aspect, a method of manufacturing a composite component is provided. The method includes providing a plurality of composite plies, each of the plurality of composite plies including a polymer and reinforcing fibers. The method further includes placing the plurality of composite plies in the following manner:

[0043] · A first set of composite plies is in an anisotropic configuration,

[0044] · An intermediate set of composite plies is in a quasi-isotropic configuration, and

[0045] · A second set of composite plies is in an anisotropic configuration parallel to the first set.

[0046] The intermediate set of composite plies is located between the first set of composite plies and the second set of composite plies.

[0047] Thus, the method is a method of manufacturing the composite component of the first and second aspects above.

[0048] In an example, the method may further include machining screw holes through the composite component. The screw holes may be threaded. The screw holes may be tapered.

[0049] In an example, the method includes placing a plurality of composite plies such that a middle set of composite plies is centered about a midplane between a top surface and a bottom surface of the composite component.

[0050] In other examples, the method includes placing a plurality of composite plies such that a middle set of composite plies is offset relative to a midplane between a top surface and a bottom surface of the composite component. In such examples, the middle set of composite plies is offset toward the bottom surface of the composite component.

[0051] In an example, the method may further include compression molding the plurality of composite plies.

[0052] In an example, the composite component is an implantable medical device.

[0053] In an example, the composite component is a bracket, such as a bracket for carrying a tool such as an aerospace carrier vehicle, an aircraft, a road carrier vehicle, or a rail carrier vehicle.

[0054] In an example, the composite component is planar. In other examples, the composite component is non-planar. The composite component may be molded.

[0055] Based on the following drawings, description, and claims, other technical features may be apparent to those skilled in the art.

[0056] As used herein, the term "anisotropic" means that a composite material has different strengths and stiffnesses in different directions through the material. In particular, as described herein, some portions of the composite material have an anisotropic configuration provided by a unidirectional arrangement of reinforcing fibers within the composite ply. Within the anisotropic configuration of the composite ply, the reinforcing fibers are primarily parallel to each other, thereby providing greater strength and stiffness about a bending axis perpendicular to the direction of the reinforcing fibers. However, it should be understood that within the anisotropic configuration of the composite ply, the reinforcing fibers need not all be parallel to each other, and there may be some reinforcing fibers arranged in different orientations, such as to hold other reinforcing fibers in place or to provide some torsional stiffness.

[0057] As used herein, the term "unidirectional" means that the reinforcing fibers are primarily parallel to each other, but it should be understood that some of the reinforcing fibers within a unidirectional ply may have different orientations, such as to hold other reinforcing fibers in place or to provide some torsional stiffness.

[0058] As used herein, the term "quasi-isotropic" means that the composite material has substantially isotropic properties within the plane of the composite material. That is, the strength and stiffness of a quasi-isotropic composite material are substantially the same in any direction within the plane of the composite material. This is typically achieved by providing reinforcing fibers at different angles within the ply, preferably in a balanced and symmetric manner. However, it should be understood that a quasi-isotropic composite material need not be completely isotropic within the plane of the composite material, but may have directions with higher strength and stiffness than other directions. For example, a ply including reinforcing fibers at 0 degrees and 90 degrees with respect to the bending axis may be considered quasi-isotropic. Similarly, a quasi-isotropic ply may include reinforcing fibers at + / -45 degrees, + / -90 degrees, and 0 degrees with respect to the bending axis, or reinforcing fibers at + / -22.5 degrees, + / -45 degrees, + / -90 degrees, and 0 degrees with respect to the bending axis, or reinforcing fibers at + / -30 degrees, + / -60 degrees, and 0 degrees with respect to the bending axis.

[0059] All features (including any appended claims, abstract, and drawings) disclosed in this specification and / or all steps of any method or process so disclosed may be combined in any combination, except for combinations of at least some of such features and / or steps that are mutually exclusive. Each feature disclosed in this specification (including any appended claims, abstract, and drawings) may be replaced by an alternative feature for the same, equivalent, or similar purpose, unless expressly stated otherwise. Thus, unless otherwise expressly stated, each feature disclosed is only one example of a series of equivalent or similar features.

[0060] The invention is not limited to the details of one or more of the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification (including any appended claims, abstract, and drawings), or to any novel step or any novel combination of steps of any method or process so disclosed.

[0061] Brief Description of the Several Views of the Drawings

[0062] To facilitate easy identification of the discussion of any particular element or action, one or more of the most significant digits in the reference numerals refer to the figure number in which the element was first introduced.

[0063] The invention will now be described with reference to the drawings, in which:

[0064] Figure 1A A composite component, particularly a fracture fixation plate, is shown.

[0065] Figure 1B Shows Figure 1A A cross-section of the screw hole of the composite component of

[0066] Figure 2 Shows additional example composite parts, particularly brackets.

[0067] Figure 3 Shows Figure 1A 、 Figure 1B and Figure 2 The cross-section of the first example composite material of the composite part of.

[0068] Figure 4 Shows Figure 1A 、 Figure 1B and Figure 2 The cross-section of the second example composite material of the composite part of. Detailed Description

[0069] As described below, the present invention relates to composite parts formed from composite materials. The composite material is a polymer composite material formed from a polymer and reinforcing fibers.

[0070] Polymer

[0071] In a preferred example, the polymer of the composite material is polyaryletherketone. Any suitable polyaryletherketone can be used in the composite material of the present invention. The suitable polyaryletherketone may have a repeating unit of formula (I):

[0072]

[0073] wherein t1 and w1 independently represent 0 or 1, and v1 represents 0, 1 or 2.

[0074] The polyaryletherketone suitably comprises at least 90 mol%, 95 mol% or 99 mol% of the repeating unit of formula (I).

[0075] The polyaryletherketone may contain the repeating unit of formula (I) or consist essentially of the repeating unit of formula (I). The preferred polymer material contains the repeating unit (or consists essentially of the repeating unit), wherein t1 = 1, v1 = 0 and w1 = 0; t1 = 0, v1 = 0 and w1 = 0; t1 = 0, w1 = 1, v1 = 2; or t1 = 0, v1 = 1 and w1 = 0. More preferably, the polyaryletherketone contains repeating unit I (e.g., consists essentially of repeating unit I), wherein t1 = 1, v1 = 0 and w1 = 0; or t1 = 0, v1 = 0 and w1 = 0. Most preferably, the polyaryletherketone includes the repeating unit (especially consists essentially of the repeating unit), wherein t1 = 1, v1 = 0 and w1 = 0.

[0076] In a preferred embodiment, the polyaryletherketone is selected from polyetheretherketone, polyetherketone, polyetherketoneetherketoneketone and polyetherketoneketone. In a more preferred embodiment, the polyaryletherketone is polyetheretherketone or PEEK.

[0077] In some examples, the polyaryletherketone (e.g., PEEK) can have at least 4 KJ / m² -2 , preferably at least 5 KJ / m² -2 , more preferably at least 6 KJ / m² -2 of the Izod notched impact strength (specimen 80 mm × 10 mm × 4 mm (Type A) with a 0.25 mm notch, tested at 23 °C according to ISO 180). The Izod notched impact strength measured as described above can be less than 10 KJ / m² -2 , suitably less than 8 KJ / m² -2 . The Izod notched impact strength measured as described above can be at least 3 KJ / m² -2 , suitably at least 4 KJ / m² -2 , preferably at least 5 KJ / m² -2 . The Izod notched impact strength can be less than 50 KJ / m² -2 , suitably less than 30 KJ / m².

[0078] The polyaryletherketone (e.g., PEEK) suitably has at least 0.06 kN·s / m -2 of the melt viscosity (MV), preferably has at least 0.09 kN·s / m -2 , more preferably at least 0.12 kN·s / m -2 of the MV. The polyaryletherketone (e.g., PEEK) can have less than 1.00 kN·s / m -2 , preferably less than 0.5 kN·s / m -2 of the MV.

[0079] The polyaryletherketone (e.g., PEEK) can have an MV in the range of 0.09 kN·s / m -2 to 0.5 kN·s / m -2 , preferably in the range of 0.1 kN·s / m -2 to 0.3 kN·s / m -2 , preferably has an MV in the range of 0.1 kN·s / m -2 to 0.2 kN·s / m -2 . An MV of 0.15 kN·s / m -2 has been found to be particularly advantageous. The MV is suitably measured using a capillary rheometer (using a tungsten carbide die, 0.5 mm × 3.175 mm, shear rate of 1000 s⁻¹, operating at 400 °C).

[0080] In a preferred embodiment, the polyaryletherketone (e.g., PEEK) has a melt viscosity (MV) of 0.09 kN·s / m -2 to 0.5 kN·s / m -2 .

[0081] The polyaryletherketone (e.g., PEEK) can be amorphous or semi-crystalline. The polyaryletherketone is preferably crystalline. The polyaryletherketone is preferably semi-crystalline. For example, as described by Blundell and Osborn (Polymer 24, 953, 1983), the level and degree of crystallinity in the polymer are preferably measured by wide-angle X-ray diffraction (also known as wide-angle X-ray scattering or WAXS). Alternatively, the crystallinity can be evaluated by differential scanning calorimetry (DSC).

[0082] The crystallinity level of the polyaryletherketone (e.g., PEEK) can be at least 1%, suitably at least 3%, preferably at least 5% and more preferably at least 10%. In a particularly preferred embodiment, the crystallinity can be greater than 25%. The crystallinity can be less than 50% or less than 40%.

[0083] The main peak of the melting endotherm (Tm) of the polyaryletherketone (if crystalline) can be at least 300 °C. In the case of using, for example, PEEK, the main peak of the melting endotherm (Tm) can be at least 300 °C.

[0084] The composite material can contain any suitable amount of polyaryletherketone (e.g., PEEK). For example, the composite material can contain at least 20% by volume, preferably at least 25% by volume, more preferably at least 30% by volume, still more preferably at least 35% by volume, even more preferably at least 37% by volume, and most preferably at least 39% by volume of polyaryletherketone (e.g., PEEK). The composite material contains at most 48% by volume of polyaryletherketone (e.g., PEEK). In some embodiments, the composite material can contain at most 45% by volume, at most 43% by volume of polyaryletherketone (e.g., PEEK).

[0085] In some embodiments, the composite material can contain 20% to 48% by volume, preferably 30% to 48% by volume, more preferably 35% to 48% by volume, still more preferably 37% to 48% or 38% to 48% by volume of polyaryletherketone (e.g., PEEK). More preferably, the composite material can contain 39% to 48% by volume, even more preferably 39% to 45% by volume of polyaryletherketone (e.g., PEEK). In some embodiments, the composite material can contain 39% to 43% by volume of polyaryletherketone (e.g., PEEK).

[0086] The volume ratio of the reinforcing fiber to the polyaryletherketone (e.g., PEEK) is from 1.1:1 to 1.5:1, such as from 1.2:1 to 1.4:1.

[0087] Reinforcing fiber

[0088] Any suitable reinforcing fiber can be used. The fibers used can be selected from inorganic fiber materials or organic fiber materials. The fibers can have a melting temperature or decomposition temperature greater than 200 °C, such as greater than 250 °C or greater than 300 °C. In some embodiments, the fibers can have a melting temperature greater than 350 °C or 500 °C. Examples of suitable fibers include aramid fibers, carbon fibers, glass fibers, silica fibers, zirconia fibers, silicon nitride fibers, boron fibers, and potassium titanate fibers. The most preferred fiber is carbon fiber.

[0089] The reinforcing fiber (e.g., carbon fiber) can have a tensile strength greater than 4200 MPa, preferably greater than 4500 MPa, more preferably greater than 4800 MPa.

[0090] The reinforcing fiber (e.g., carbon fiber) can have a tensile modulus greater than 200 GPa, preferably greater than 230 GPa, more preferably greater than 240 GPa.

[0091] The reinforcing fiber (e.g., carbon fiber) can have a failure strain greater than 1.1%, preferably greater than 1.2%, 1.4% or 1.6%. The reinforcing fiber (e.g., carbon fiber) can have a failure strain less than 2.2%, such as less than 2.0% or 1.9%. In some embodiments, the reinforcing fiber (e.g., carbon fiber) can have a failure strain of 1.2% to 2.2%, such as 1.4% to 2.0% or 1.6% to 1.9%. In one embodiment, the reinforcing fiber (e.g., carbon fiber) can have a failure strain of 1.7% to 1.9%.

[0092] The mass per unit length of the reinforcing fiber (e.g., carbon fiber) can be from 0.1 g / m to 1.0 g / m, such as from 0.2 g / m to 0.8 g / m. In some embodiments, from 0.2 g / m to 0.5 g / m.

[0093] The reinforcing fiber (e.g., carbon fiber) can have a density greater than 1.65 g / cm 3 , preferably greater than 1.70 g / cm 3 . The reinforcing fiber (e.g., carbon fiber) can have a density less than 1.85 g / cm 3 , preferably less than 1.80 g / cm 3 . In some embodiments, the reinforcing fiber (e.g., carbon fiber) can have a density of 1.70 g / cm 3 to 1.85 g / cm 3 , such as 1.75 g / cm 3 to 1.80 g / cm 3 , or 1.78 g / cm 3 to 1.79 g / cm 3 .

[0094] Reinforcing fibers (e.g., carbon fibers) can be provided in the form of continuous tows. Any suitable tow size can be used. The tow size indicates the number of filaments in the tow. In some embodiments, the tow size can be from 1,000 to 24,000. In one embodiment, a tow size of from 6,000 to 12,000 can be employed.

[0095] Examples of suitable reinforcing fibers include, for example, those supplied by Hexcel Corporation under the trademark of carbon fibers.

[0096] As described above, the composite material of the present invention comprises a polyaryletherketone and a reinforcing fiber.

[0097] The composite material can be formed into a sheet or tape, referred to as a ply. For example, the reinforcing fiber (e.g., carbon fiber) can be combined with a polyaryletherketone (e.g., PEEK) and formed into a composite ply. The ply can be formed, for example, using heat and / or compression. In one embodiment, the polyaryletherketone (e.g., PEEK) can be heated to a temperature above its softening temperature or melting temperature to melt or soften the polymer around the fiber to form the composite material. The molten polymer or softened polymer is then compressed around the fiber to form the ply.

[0098] When heated, suitable temperatures include 320 °C and higher temperatures, preferably 330 °C and higher temperatures, more preferably 340 °C and higher temperatures. In some embodiments, the compression molding can be carried out at a temperature of 320 °C to 450 °C, preferably 330 °C to 400 °C, more preferably 340 °C to 380 °C, and even more preferably 350 °C to 370 °C. Suitably, a pressure of at least 1.5 MPa or at least 2 MPa can be applied. Examples of suitable pressure ranges are from 1.5 MPa to 10 MPa, such as from 2 MPa to 8 MPa.

[0099] The composite ply formed using the composite material of the present invention can have a thickness of from 10 microns to 1 mm, preferably from 100 microns to 300 microns, more preferably from 140 microns to 200 microns.

[0100] The composite ply can be used to form composite components, such as, for example, the medical implants or brackets described below.

[0101] Composite part

[0102] Figure 1A A composite component is shown, in particular a fracture fixation plate 102. In use, the fracture fixation plate 102 is attached to a bone, bone portion, and / or bone fragment. The fracture fixation plate 102 is attached across the fracture site to hold the bone in place and promote healing.

[0103] The exemplary fracture fixation plate 102 shown has a generally elongated form with a first end 104 and a second end 106 disposed along a longitudinal axis 120. The fracture fixation plate 102 has a top surface 126 and a bottom surface, particularly a bone-facing surface 128. In use, the bone-facing surface 128 is placed against the bone.

[0104] The first end 104 is screwed to the first side of the fracture site, and the second end 106 is screwed to the second side of the fracture site. Screw holes 108 are provided for screwing the fracture fixation plate 102 to the bone and bone fragments. Only a single screw 110 is shown, but it should be understood that multiple screws are used. The fracture fixation plate 102 has a plurality of screw holes 108a, 108b, 108c, and the surgeon can select which screw hole to use during the operation based on the bone shape, integrity, and the location of the fracture and any bone fragments. Additional screw holes 112 may be provided in the first end 104 and / or the second end 106, for example, for smaller screws that are used for smaller bone fragments.

[0105] After the fracture fixation plate 102 has been attached across the fracture site, when the patient moves and loads are applied to the bone and the fracture fixation plate 102, it is subjected to bending stresses. The bending stresses are typically applied about a bending axis 122 that is perpendicular to the longitudinal axis 120. As shown, the bending axis 122 may be generally located at the demarcation between the first end 104 and the second end 106, but it may be located at any position along the fracture fixation plate 102, depending on the nature of the fracture and the relative position of the fracture fixation plate 102 on the bone. Additionally, it should be understood that the bending axis 122 may be located in the plane of the fracture fixation plate 102 as shown, or it may be offset from the fracture fixation plate 102, for example, towards or away from the bone, depending on the geometry of the fracture and the bone and the use of the bone during patient movement.

[0106] Once attached across the fracture site, the fracture fixation plate 102 is configured to hold the ends of the fractured bone in close proximity while allowing a small degree of movement through flexion. Thus, the fracture fixation plate 102 holds the bone in place and bears the loads applied to the bone, while flexion promotes bone healing.

[0107] The fracture fixation plate 102 may be planar (i.e., flat), but typically has a contour that matches the bone to which it is attached. The size, shape, and contour of the fracture fixation plate 102 may be adapted to the particular bone for which it will be used. For example, a fracture fixation plate 102 for a fractured humerus will be smaller and thinner than a fracture fixation plate 102 for a fractured femur because the bones have different sizes and shapes and because the fracture fixation plate 102 will be subjected to different magnitudes of loads once attached.

[0108] As described in more detail below, the fracture fixation plate 102 is formed from a composite material having a polymer and reinforcing fibers. The composite material is formed from a plurality of composite laminae. Each composite lamina includes reinforcing fibers and a polymer. The composite laminae are placed and then compression molded to fuse the laminae together by melting or softening the polymer, thereby producing a bonded composite material. The form of the mold determines the profile of the composite material and the fracture fixation plate 102, thereby allowing the fracture fixation plate 102 to be planar or non-planar.

[0109] In other examples, Figure 1A the composite components shown in may be another type of orthopedic implant, intramedullary nail, spinal implant (such as a cage, rod or screw), or other load-bearing implantable component.

[0110] Figure 1B A cross-section through the fracture fixation plate 102 at the screw holes 108a is shown. The same cross-section applies to the screw holes 112. As shown, the screw holes 108a, 112 are tapered, having a larger diameter at the top surface 126 than at the bone-facing surface 128. The screw holes 108a, 112 have tapered screw hole surfaces 118. In some examples, the screw holes 108a, 112 may be threaded. In other examples, the screw holes 108a, 112 may be plain through-holes (i.e., unthreaded). The screw holes 108a, 112 may be machined after the composite material is formed.

[0111] The screw 110 is positioned in the screw holes 108a, 112. The screw 110 has a threaded screw shaft 116. If the screw holes 108a, 112 are threaded, the screw shaft 116 may threadedly engage at least a portion of the screw holes 108a, 112. Similarly, if the screw holes 108a, 112 are threaded, the screw head 114 may be at least partially threaded and may threadedly engage at least a portion of the threads of the screw holes 108a, 112. The screw shaft 116 engages the underlying bone to attach the fracture fixation plate 102 to the bone.

[0112] As shown, the screw 110 includes a screw shaft 116 and a screw head 114 received in the screw hole 108a. The screw head 114 has a tapered profile that mates with and abuts against the tapered screw hole surface 118 of the screw holes 108a, 112. The abutment between the screw head 114 and the tapered screw hole surface 118 applies a circumferential strain to the fracture fixation plate 102 at the screw holes 108a, 112 by pushing the composite material outward where the screw head 114 contacts the screw hole 108a. Due to the taper of the screw head 114 and the tapered screw hole surface 118, the circumferential strain is greater toward the smaller diameter side of the screw hole 108a (i.e., toward the bone-facing surface 128). In particular, the circumferential strain applied to the fracture fixation plate 102 is at Figure 1Bis greatest in the region 124 of higher circumferential strain as shown. As Figure 1B shown, the region 124 of higher circumferential strain is offset towards the bone-facing surface 128 (i.e., closer to the bone-facing surface 128 compared to the top surface 126). The higher circumferential strain applied in the region 124 of higher circumferential strain will impart a greater circumferential stress at that location.

[0113] In other examples, depending on the relative sizes of the screw holes 108a, 112 and the screw 110 (especially the screw head 114), the region 124 of higher circumferential strain can be located at different positions between the top surface 126 and the bone-facing surface 128.

[0114] In some examples, the screw holes 108a, 108b, 108c, 112 of the fracture fixation plate 102 can be non-tapered and can be straight through-holes in the fracture fixation plate 102.

[0115] In Figure 2 the example, the composite component is the bracket 202. The bracket 202 can be used in a vehicle (such as an aerospace vehicle, a road vehicle or a rail vehicle). The bracket 202 is generally elongated along the longitudinal axis 208. The bracket can be planar or non-planar, for example, the bracket 202 can include a bend. The bracket 202 has a top surface 212 and an opposite bottom surface which is not shown in Figure 2 here.

[0116] The bracket 202 includes a first end 214 having a plurality of screw holes 204a, 204b, 204c, 204d. The bracket 202 includes a second end 216 having a plurality of screw holes 206a, 206b, 206c, 206d. The screw holes 204a, 204b, 204c, 204d, 206a, 206b, 206c, 206d are for attaching the bracket 202 to another component. The bracket 202 can be attached to another component on its top surface 212 and / or on its bottom surface.

[0117] During use, when the bracket 202 is attached to another component, the bracket 202 may be subjected to bending stress applied generally about the bending axis 210. As shown, the bending axis 210 can be generally perpendicular to the longitudinal axis 208. However, in some applications, the bending axis 210 can be oriented otherwise relative to the longitudinal axis 208.

[0118] The screw holes 204a, 204b, 204c, 204d, 206a, 206b, 206c, 206d of the bracket 202 can be tapered as referenced Figure 1BAs described. Alternatively, the screw holes 204a, 204b, 204c, 204d, 206a, 206b, 206c, 206d of the bracket 202 can be straight through holes. In some examples, the screw holes 204a, 204b, 204c, 204d, 206a, 206b, 206c, 206d of the bracket 202 can be threaded. In other examples, the screw holes 204a, 204b, 204c, 204d, 206a, 206b, 206c, 206d of the bracket 202 can be plain (i.e., unthreaded).

[0119] As described in more detail below, the bracket 202 is formed of a composite material having a polymer and reinforcing fibers. The composite material is formed from a plurality of composite plies. Each composite ply includes reinforcing fibers and a polymer. The composite plies are placed and then compression molded to fuse the plies together by melting or softening the polymer, thereby producing a bonded composite material. The form of the mold determines the profile of the composite material and the bracket 202, thereby allowing the bracket 202 to be planar or non-planar.

[0120] Figure 3 is shown Figure 1A and Figure 1B of the fracture fixation plate 102 and / or Figure 2 of the bracket 202 of the first example layup of the composite material 302. As shown, the composite material 302 includes a plurality of composite plies 314a, 314b, 316a, 316b, 318a, 318b. Each composite ply 314a, 314b, 316a, 316b, 318a, 318b includes a plurality of reinforcing fibers (particularly carbon fibers) and a polymer. In each composite ply 314a, 314b, 316a, 316b, 318a, 318b, the reinforcing fibers are arranged in a unidirectional manner, i.e., substantially parallel to each other. In particular, in each composite ply 314a, 314b, 316a, 316b, 318a, 318b, most of the reinforcing fibers are parallel to each other. The composite plies 314a, 314b, 316a, 316b, 318a, 318b are arranged in a layup pattern, as Figure 3 shown. Once placed, the assembled composite material 302 is heated and compressed to form a composite part, such as Figure 1A and Figure 1B of the fracture fixation plate 102 or Figure 2 of the bracket 202.

[0121] As Figure 3 shown, the composite plies 314a, 314b, 316a, 316b, 318a, 318b are arranged as follows:

[0122] · A first set of composite plies 308 is located at the top surface 304 of the composite material 302,

[0123] · The second set of composite laminae 310 is located at the bottom surface 306 of the composite material 302, and

[0124] · The intermediate set of composite laminae 312 is located between the first set of composite laminae 308 and the second set of composite laminae 310.

[0125] The first set of composite laminae 308 has an anisotropic ply layup. In particular, the composite laminae 314a, 314b of the first set of composite laminae 308 are arranged substantially unidirectionally. That is, the composite laminae 314a, 314b of the first set of composite laminae 308 are arranged such that most of the reinforcing fibers of the composite laminae are substantially parallel to each other. As shown in FIGS. 1 and Figure 2 as shown, the reinforcing fibers of the first set of composite laminae 308 are arranged substantially parallel to the longitudinal axes 120, 208 of the fracture fixation plate 102 or the bracket 202, respectively. Accordingly, the first set of composite laminae 308 mainly provides bending stiffness about the bending axes 122, 210 of the fracture fixation plate 102 or the bracket 202, respectively.

[0126] Similarly, the second set of composite laminae 310 has an anisotropic ply layup. In particular, the composite laminae 316a, 316b of the second set of composite laminae 310 are arranged unidirectionally. That is, the composite laminae 316a, 316b of the second set of composite laminae 310 are arranged such that most of the reinforcing fibers of the composite laminae are substantially parallel to each other. The reinforcing fibers of the second set of composite laminae 310 are arranged substantially parallel to the longitudinal axes 120, 208 of the fracture fixation plate 102 or the bracket 202, respectively. Accordingly, the second set of composite laminae 310 mainly provides bending stiffness about the bending axes 122, 210 of the fracture fixation plate 102 or the bracket 202, respectively.

[0127] The intermediate set of composite laminae 312 has a quasi-isotropic ply layup. That is, the composite laminae 316a, 316b of the intermediate set of composite laminae 312 are arranged at different orientations relative to each other and relative to the longitudinal axes 120, 208 of the fracture fixation plate 102 or the bracket 202. The intermediate set of composite laminae 312 may include balanced and / or symmetric ply layups. Accordingly, the intermediate set of composite laminae 312 provides substantially uniform bending stiffness in each direction, and also provides torsional stiffness and shear stiffness to an extent not provided by the anisotropic configurations of the first set of composite laminae 308 and the second set of composite laminae 310.

[0128] In the example shown, the composite material 302 includes 19 composite laminae, where the first set of composite laminae 308 and the second set of composite laminae 310 each have five composite laminae 314a, 314b, 318a, 318b, and the middle set of composite laminae 312 has nine composite laminae 316a, 316b. However, in other examples, there may be a different number of composite laminae in each set. In the example, the first set of composite laminae 308, the second set of composite laminae 310, and the middle set of composite laminae 312 each include at least two composite laminae, such as at least three composite laminae, such as at least four composite laminae, such as at least five composite laminae. As shown, in this example, the first set of composite laminae 308 and the second set of composite laminae 310 have the same number of composite laminae, and thus the middle set of composite laminae 312 is centered about the midplane 320 of the composite material 302 (i.e., the middle of the middle set of composite laminae 312 is aligned with the midpoint between the top surface 304 and the bottom surface 406).

[0129] In the example, all of the composite laminae 314a, 314b, 318a, 318b of the first set of composite laminae 308 and the second set of composite laminae 310 are substantially parallel to each other. However, it should be understood that some of the composite laminae 314a, 314b, 318a, 318b may have different orientations, varying from parallel to the longitudinal axes 120, 208 of the composite component, while the first set of composite laminae 308 and the second set of composite laminae 310 can still have a substantially anisotropic configuration. That is, the first set of composite laminae 308 and the second set of composite laminae 310 are primarily anisotropic, where most of the reinforcing fibers are parallel to each other and parallel to the longitudinal axes 120, 208 of the composite component, but this does not exclude a few reinforcing fibers having different orientations.

[0130] As described above, the intermediate set of composite laminae 312 has a quasi-isotropic configuration. In an example, the intermediate set of composite laminae 312 may include composite laminae having reinforcing fibers oriented at + / - 45 degrees, + / - 90 degrees, and 0 degrees, respectively, relative to the longitudinal axes 120, 208 of the fracture fixation plate 102 and the bracket 202. In other examples, the intermediate set of composite laminae 312 may include a quasi-isotropic ply stack having composite laminae with reinforcing fibers oriented at + / - 22.5 degrees, + / - 45 degrees, + / - 90 degrees, and 0 degrees, respectively, relative to the longitudinal axes 120, 208 of the fracture fixation plate 102 and the bracket 202. In other examples, the intermediate set of composite laminae 312 may include a quasi-isotropic ply stack having composite laminae with reinforcing fibers oriented at + / - 30 degrees, + / - 60 degrees, and 0 degrees, respectively, relative to the longitudinal axes 120, 208 of the fracture fixation plate 102 and the bracket 202. It should be understood that a quasi-isotropic ply stack may include composite laminae having reinforcing fibers with different orientations to provide substantially uniform flexural stiffness in any direction, which also provides higher torsional and shear stiffness.

[0131] It should also be understood that additional composite laminae may be provided between the first set of composite laminae 308 and the top surface 304, and / or between the second set of composite laminae 310 and the bottom surface 306. Additionally, additional composite laminae or sets of composite laminae may be provided between the first set of composite laminae 308 and the intermediate set of composite laminae 312, and / or between the second set of composite laminae 310 and the intermediate set of composite laminae 312. Such additional composite laminae or sets may provide surface finish or additional thickness to the composite material 302.

[0132] The anisotropic configuration of the first set of composite laminae 308 and the second set of composite laminae 310 and their positions at or near the top surface 304 and the bottom surface 306 provide improved flexural stiffness compared to a fully quasi-isotropic ply stack. In particular, the portions of the composite material 302 located closest to the top surface 304 and the bottom surface 306 will experience the greatest tension and compression during bending, and thus providing anisotropic composite material at these locations increases the flexural stiffness of the composite material 302.

[0133] Advantageously, with reference to Figure 1B and Figure 3 , the position of the intermediate set of composite laminae 312 within the thickness of the composite material 302 may correspond to Figure 1BRegion 124 of higher circumferential strain as shown. This can occur if the screw head 114 (at least the lower part thereof) of the screw 110 abuts the tapered screw hole surface 118 at the location where the intermediate set of composite laminae 312 is located within the screw holes 108a, 112. Thus, the circumferential stress is better handled by the composite material 302 because the quasi-isotropic configuration of the intermediate set of composite laminae 312 resists the circumferential stress, while the first set of composite laminae 308 and the second set of composite laminae 310 mainly provide increased flexural stiffness.

[0134] Figure 4 is shown Figure 1A and Figure 1B fracture fixation plate 102 of Figure 2 and / or additional example layups of the composite material 402 of the bracket 202 of Figure 4 As shown, the composite material 402 includes a plurality of composite laminae 414a, 414b, 416a, 416b, 418a, 418b. Each composite lamina 414a, 414b, 416a, 416b, 418a, 418b includes a plurality of reinforcing fibers (especially carbon fibers) and a polymer. In each composite lamina 414a, 414b, 416a, 416b, 418a, 418b, the reinforcing fibers are arranged in a mainly unidirectional manner, i.e., substantially parallel to each other. The composite laminae 414a, 414b, 416a, 416b, 418a, 418b are arranged in a layup pattern as Figure 4 shown. Once placed, the assembled composite material 402 is heated and compressed to form a composite part, such as Figure 1A and Figure 1B the fracture fixation plate 102 of Figure 2 or the bracket 202 of

[0135] As Figure 4 shown, the composite laminae 414a, 414b, 416a, 416b, 418a, 418b are arranged as follows:

[0136] · A first set of composite laminae 408 is located at the top surface 404 of the composite material 402,

[0137] · A second set of composite laminae 410 is located at the bottom surface 406 of the composite material 402, and

[0138] · An intermediate set of composite laminae 412 is located between the first set of composite laminae 408 and the second set of composite laminae 410.

[0139] The first set of composite laminae 408 has an anisotropic layup. In particular, the composite laminae 414a, 414b of the first set of composite laminae 408 are arranged unidirectionally. That is, the composite laminae 414a, 414b of the first set of composite laminae 408 are arranged such that most of the reinforcing fibers of the composite laminae are substantially parallel to each other. As shown in FIGS. 1 and Figure 2 as shown, the reinforcing fibers of the first set of composite laminae 408 are arranged substantially parallel to the longitudinal axes 120, 208 of the fracture fixation plate 102 or the bracket 202, respectively. Thus, the first set of composite laminae 408 primarily provides bending stiffness about the bending axes 122, 210 of the fracture fixation plate 102 or the bracket 202, respectively.

[0140] Similarly, the second set of composite laminae 410 has an anisotropic layup. In particular, the composite laminae 416a, 416b of the second set of composite laminae 410 are arranged unidirectionally. That is, the composite laminae 416a, 416b of the second set of composite laminae 410 are arranged such that most of the reinforcing fibers of the composite laminae are substantially parallel to each other. The reinforcing fibers of the second set of composite laminae 410 are arranged substantially parallel to the longitudinal axes 120, 208 of the fracture fixation plate 102 or the bracket 202, respectively. Thus, the second set of composite laminae 410 primarily provides bending stiffness about the bending axes 122, 210 of the fracture fixation plate 102 or the bracket 202, respectively.

[0141] The intermediate set of composite laminae 412 has a quasi-isotropic layup. That is, the composite laminae 416a, 416b of the intermediate set of composite laminae 412 are arranged at different orientations relative to each other and relative to the longitudinal axes 120, 208 of the fracture fixation plate 102 or the bracket 202. The intermediate set of composite laminae 412 may include a balanced and / or symmetric layup. Thus, the intermediate set of composite laminae 412 provides substantially uniform bending stiffness in each direction and also provides a certain degree of torsional stiffness and shear stiffness not provided by the anisotropic configurations of the first set of composite laminae 408 and the second set of composite laminae 410.

[0142] In the example shown, the composite material 402 includes nineteen composite laminae 414a, 414b, 416a, 416b, 418a, 418b. The first set of composite laminae 408 includes nine composite laminae 414a, 414b, and the second set of composite laminae 410 includes two composite laminae 418a, 418b. The intermediate set of composite laminae 412 has eight composite laminae 416a, 416b. However, in other examples, there may be a different number of composite laminae in each set. In the example, the first set of composite laminae 408, the second set of composite laminae 410, and the intermediate set of composite laminae 412 each include at least two composite laminae, such as at least three composite laminae, such as at least four composite laminae, such as at least five composite laminae. In this example, the first set of composite laminae 408 and the second set of composite laminae 410 have a different number of composite laminae. Accordingly, the intermediate set of composite laminae 412 is offset relative to the intermediate plane 420 of the composite material 402. In this example, the intermediate set of composite laminae 412 is offset from the intermediate plane 420 of the composite material 402 toward the bottom surface 406. It should be understood that although offset from the intermediate plane 420, the intermediate set of composite laminae 412 still overlaps the intermediate plane 420. In other examples, the intermediate set of composite laminae 412 may be offset to a greater extent such that there is no overlap between the intermediate set of composite laminae 412 and the intermediate plane 420.

[0143] In the example, all of the composite laminae 414a, 414b, 418a, 418b of the first set of composite laminae 408 and the second set of composite laminae 410 are parallel to each other. However, it should be understood that some of the composite laminae 414a, 414b, 418a, 418b may have different orientations, varying from parallel to each other to parallel to the longitudinal axes 120, 208 of the composite component, while the first set of composite laminae 408 and the second set of composite laminae 410 may still have a substantially anisotropic configuration. That is, the first set of composite laminae 408 and the second set of composite laminae 410 are primarily anisotropic, where most of the reinforcing fibers are parallel to each other and parallel to the longitudinal axes 120, 208 of the composite component, but this does not exclude a few reinforcing fibers having different orientations.

[0144] As described above, the intermediate set of composite laminae 412 has a quasi-isotropic configuration. In an example, the intermediate set of composite laminae 412 may include composite laminae having reinforcing fibers oriented at + / -45 degrees, + / -90 degrees, and 0 degrees relative to the longitudinal axes 120, 208 of the fracture fixation plate 102 and the bracket 202, respectively. In other examples, the intermediate set of composite laminae 412 may include a quasi-isotropic ply stack having composite laminae with reinforcing fibers oriented at + / -22.5 degrees, + / -45 degrees, + / -90 degrees, and 0 degrees relative to the longitudinal axes 120, 208 of the fracture fixation plate 102 and the bracket 202, respectively. In other examples, the intermediate set of composite laminae 412 may include a quasi-isotropic ply stack having plies with reinforcing fibers oriented at + / -30 degrees, + / -60 degrees, and 0 degrees relative to the longitudinal axes 120, 208 of the fracture fixation plate 102 and the bracket 202, respectively. It should be understood that a quasi-isotropic ply stack may include composite laminae of different orientations to provide substantially uniform flexural stiffness in any direction, which also provides torsional stiffness and shear stiffness.

[0145] It should also be understood that additional composite laminae may be provided between the first set of composite laminae 408 and the top surface 404, and / or between the second set of composite laminae 410 and the bottom surface 406. Additionally, additional composite laminae or sets of composite laminae may be provided between the first set of composite laminae 408 and the intermediate set of composite laminae 412, and / or between the second set of composite laminae 410 and the intermediate set of composite laminae 412. Such additional composite laminae or sets of composite laminae may provide a surface finish or additional thickness to the composite material 402.

[0146] The anisotropic configurations of the first set of composite laminae 408 and the second set of composite laminae 410 and their positions at or near the top surface 404 and the bottom surface 406 provide improved flexural stiffness compared to a fully quasi-isotropic ply stack. In particular, the portions of the composite material 402 located closest to the top surface 404 and the bottom surface 406 will experience the greatest tension and compression during bending, and thus providing anisotropic composite fibers at these locations increases the flexural stiffness of the composite material 402. Additionally, during use, for example when the fracture fixation plate 102 is fixed to bone, the composite laminae closer to the top surface 404 will be primarily in strain rather than compression. Generally, the reinforcing fibers of composite laminae have greater strength under tensile loads than under compression, and thus having a higher number of composite laminae in the first set of composite laminae 408 than in the second set of composite laminae 410 can provide improved flexural stiffness for a given total number of composite laminae.

[0147] Advantageously, with reference to Figure 1B and Figure 4, the position of the intermediate set of composite plies 412 within the thickness of the composite material 402 may correspond to Figure 1B the region 124 of higher circumferential strain shown in. This can occur if the screw head 114 (at least the lower part thereof) of the screw 110 abuts the tapered screw hole surface 118 at the position where the intermediate set of composite plies 412 is located within the screw holes 108a, 112. That is, the region 124 of higher circumferential strain can be aligned with the intermediate set of composite plies 412. Thus, the circumferential stress is better handled by the composite material 402 because the quasi-isotropic configuration of the intermediate set of composite plies 412 resists the circumferential stress, while the first set of composite plies 408 and the second set of composite plies 410 mainly provide increased flexural stiffness. Shifting the position of the intermediate set of composite plies 412 from the intermediate plane 420 so that the intermediate set of composite plies 412 moves towards the smaller diameter side of the tapered screw hole 108a further improves the ability of the composite material 402 to resist the circumferential strain applied by the screw head 114.

[0148] Although the invention has been shown and described in detail in the drawings and foregoing description, these should be regarded as illustrative rather than restrictive, it being understood that only the preferred embodiments have been shown and described, and all changes and modifications falling within the spirit of the invention are desired to be protected.

[0149] It should be understood that although the use of words such as preferred, preferably, preferable or more preferable in the foregoing description indicates that the features so described may be more desirable, it may not be necessary, and embodiments lacking these features may be considered within the scope of the invention, which is defined by the appended claims. When reading the claims, when words such as "a", "an", "at least one" or "at least a part" are used, it is not intended to limit the claims to only one item unless expressly stated to the contrary in the claims. When the language "at least a part" and / or "a part" is used, the item may include a part and / or the whole item unless otherwise specifically stated to the contrary.

Claims

1. A composite component adapted to resist bending about a bending axis during use, the composite component comprising a composite material formed from a plurality of composite laminae having a polymer and reinforcing fibers, the plurality of composite laminae being arranged such that: A first set of composite laminae is arranged in a substantially anisotropic ply orientation, wherein the reinforcing fibers are substantially perpendicular to the bending axis; A second set of composite laminae is arranged in a substantially anisotropic ply orientation, wherein the reinforcing fibers are substantially perpendicular to the bending axis, and An intermediate set of composite laminae is arranged in a substantially quasi-isotropic ply orientation and is disposed between the first set of composite laminae and the second set of composite laminae.

2. The composite component according to claim 1, the composite component further comprising one or more screw holes extending through the composite component for attachment of the component using screws during use.

3. The composite component according to claim 2, wherein the one or more screw holes are threaded screw holes.

4. The composite component according to claim 2 or 3, wherein the one or more screw holes are tapered.

5. The composite component according to claim 4, wherein in use, the screw head of the screw abuts a tapered surface of one or more of the tapered screw holes, and wherein the plurality of composite laminae are arranged such that the screw head abuts the intermediate set of composite laminae.

6. The composite component according to any one of claims 1 to 5, the composite component comprising a top surface and a bottom surface.

7. The composite component according to claim 6, wherein the first set of composite laminae is disposed at or near the top surface.

8. The composite component according to claim 6 or 7, wherein the second set of composite laminae is disposed at or near the bottom surface.

9. The composite component according to any one of claims 6 to 8, wherein the intermediate set of composite laminae is centered about a mid-plane between the top surface and the bottom surface.

10. The composite component according to any one of claims 6 to 8, wherein the intermediate set of composite laminae is offset from a mid-plane between the top surface and the bottom surface.

11. The composite component according to claim 10, wherein the intermediate set of composite laminae is offset towards the bottom surface.

12. A composite component, the composite component comprising: A composite material formed from a plurality of composite laminae comprising a polymer and reinforcing fibers, the plurality of composite laminae being disposed between a top surface and a bottom surface; and Tapered screw holes extending through the composite component, the tapered screw holes having a smaller diameter at the top surface than at the bottom surface, wherein the plurality of composite laminae are arranged such that: A first set of composite laminae is disposed at or near the top surface, A second set of composite laminae is disposed at or near the bottom surface, and An intermediate set of composite laminae is disposed between the first set of composite laminae and the second set of composite laminae, the intermediate set of composite laminae comprising a quasi-isotropic ply wherein said intermediate set of composite laminae is offset towards the bottom surface from an intermediate plane between said top surface and said bottom surface.

13. The composite component according to claim 12, wherein said intermediate set of composite laminae comprises a symmetric ply layup.

14. The composite component according to claim 12 or 13, wherein said first set of composite laminae comprises substantially anisotropic plies, such as unidirectional plies.

15. The composite component according to claim 14, wherein during use, the composite component is subjected to bending about a bending axis, and wherein said first set of composite laminae is oriented such that the reinforcing fibres are substantially perpendicular to the bending axis.

16. The composite component according to any one of claims 12 to 15, wherein said second set of composite laminae comprises substantially anisotropic plies, such as unidirectional plies.

17. The composite component according to any one of claims 12 to 16, wherein during use, the composite component is subjected to bending about a bending axis, and wherein said second set of composite laminae is oriented such that the reinforcing fibres are substantially perpendicular to the bending axis.

18. The composite component according to any one of claims 1 to 17, wherein each composite lamina comprises a plurality of unidirectional reinforcing fibres.

19. The composite component according to any one of claims 1 to 18, wherein each of said first set of composite laminae and said second set of composite laminae comprises at least two composite laminae, such as at least three composite laminae, such as at least four composite laminae, such as at least five composite laminae.

20. The composite component according to any one of claims 1 to 19, wherein said intermediate set of composite laminae comprises at least five composite laminae, such as at least seven composite laminae, such as at least eight composite laminae.

21. The composite component according to any one of claims 1 to 20, wherein the composite component is elongated along a longitudinal axis substantially perpendicular to the bending axis.

22. The composite component according to any one of claims 1 to 21, wherein the composite component is an implantable medical device.

23. The composite component according to claim 22, wherein the implantable medical device is a fracture fixation plate or a trauma plate.

24. The composite component according to any one of claims 1 to 21, wherein the composite component is a bracket, such as a bracket for carrying a tool such as an aerospace carrier, an aircraft, a road vehicle or a rail vehicle.

25. The composite component according to any one of claims 1 to 24, wherein the composite component is non-planar.

26. The composite component according to any one of claims 1 to 25, wherein the composite component is compression moulded.

27. A method of manufacturing a composite component, the method comprising: providing a plurality of composite laminae comprising a polymer and reinforcing fibres, placing the plurality of composite laminae such that: a first set of composite laminae is in an anisotropic configuration, an intermediate set of composite laminae is in a quasi-isotropic configuration, and a second set of composite laminae is in an anisotropic configuration parallel to the first set, Wherein the intermediate group of composite laminates is located between the first group of composite laminates and the second group of composite laminates.

28. The method according to claim 27, further comprising machining screw holes through the composite component.

29. The method according to claim 27 or 28, comprising compression molding the plurality of composite laminates.

30. The method according to claim 29, wherein the composite component is non-planar.

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