Modular Tower Apparatus and Method of Manufacture

CROSS-REFERENCE TO RELATED APPLICATION

0001This application takes priority from U.S. Provisional Patent Application Ser. No. 61/243,375, filed Sep. 17, 2009.

BACKGROUND OF THE DISCLOSURE

00021. Field of the Disclosure

0003This application relates to producing large composite structures, including towers. In one form, the towers are utilized to support a nacelle of a wind-powered turbine. In one form, a portion of the production of the tower is accomplished offsite, with final assembly accomplished onsite.

00042. Brief Description of the Related Art

0005Composite materials are utilized to make a variety of structures, some quite large. Wind turbine towers are relatively large structures, typically up to about 20 ft. in bottom diameter and up to about 300 ft. in height (or higher). Such towers are generally made from metal alloys that are relatively heavy and expensive to manufacture. Also, such large structures are difficult to transport due to size restrictions associated with the transportation of objects over land. Therefore, it has been proposed to fabricate such towers in smaller sections and then transport and assemble such smaller sections onsite. Still, each section is relatively long and some such sections are too large in diameter for transportation. Towers made using composite materials or a combination of composite materials and metallic materials (a hybrid design) may offer viable alternatives to current all metallic towers. It may also be desirable to make other large structures, such as large storage tanks, using composite or hybrid materials.

0006The disclosure herein provides methods of making large structures utilizing composite or hybrid materials.

SUMMARY

0007In one aspect, a method of making a large composite structure is provided, which method may include providing a plurality of members each comprising a composite material, wherein each member is configured to be coupled to at least one other member in the plurality of members along a longitudinal side, coupling onsite the plurality of members along their longitudinal sides to form a base unit, and reinforcing onsite the base to form the selected structure.

0008Examples of certain features of the apparatus and method disclosed herein are summarized rather broadly in order that the detailed description thereof that follows may be better understood. There are, of course, additional features of the apparatus and methods disclosed hereinafter that will form the subject of the claims appended hereto.

BRIEF DESCRIPTION OF THE DRAWINGS

0009For detailed understanding of the present disclosure, references should be made to the following detailed description, taken in conjunction with the accompanying drawings, in which like elements have generally been given like numerals and wherein:

0010<figref idref="DRAWINGS">FIG. 1A</figref> is an isometric view of a tower made by interconnecting a plurality of conic sections, according to one embodiment of the disclosure;

0011<figref idref="DRAWINGS">FIG. 1B</figref> is an isometric view of a tower made by interconnecting a plurality of conic composite sections, with a separate portion of the tower comprised of a non-composite material, such as steel;

0012<figref idref="DRAWINGS">FIG. 1C</figref> is an isometric view of an off-shore floating tower made by interconnecting a plurality of conic composite sections with a vertical spar below the water surface;

0013<figref idref="DRAWINGS">FIG. 2</figref> is an isometric view of a single panel, from a conic section, in one form;

0014<figref idref="DRAWINGS">FIG. 3A</figref> shows cross-sectional view of two panels with half lap joints in one form;

0015<figref idref="DRAWINGS">FIG. 3B</figref> is a cross-sectional view of the panels shown in <figref idref="DRAWINGS">FIG. 3A</figref> interconnected;

0016<figref idref="DRAWINGS">FIG. 3C</figref> shows cross-sectional view of two panels with a double half-lap (also referred to as full lap) joint in one form;

0017<figref idref="DRAWINGS">FIG. 3D</figref> is a cross-sectional view of the panels shown in <figref idref="DRAWINGS">FIG. 3C</figref> interconnected together;

0018<figref idref="DRAWINGS">FIG. 4A</figref> is an isometric view of a plurality of panels placed upon a mandrel to form a conic section in one form;

0019<figref idref="DRAWINGS">FIG. 4B</figref> is an isometric view of a process of winding an outer layer onto the sections in one form;

0020<figref idref="DRAWINGS">FIG. 5A</figref> is a cross-sectional view of a full-lap joint (as illustrated in <figref idref="DRAWINGS">FIG. 3D</figref>) interconnected together with a supplemental composite laminate to enhance bonding between adjacent sections, according to one embodiment of the disclosure;

0021<figref idref="DRAWINGS">FIG. 5B</figref> is a cross-sectional view of a full lap joint (as illustrated in <figref idref="DRAWINGS">FIG. 3D</figref>) interconnected together with a supplemental composite laminate to enhance bonding between adjacent sections, according to another embodiment of the disclosure;

0022<figref idref="DRAWINGS">FIG. 6</figref> is a cross-sectional end (plan) view of a single panel in one form;

0023<figref idref="DRAWINGS">FIG. 7</figref> is a cross-sectional side view of a single panel in one form;

0024<figref idref="DRAWINGS">FIG. 8</figref> is a cross-sectional side view of a single panel in one form;

0025<figref idref="DRAWINGS">FIG. 9</figref> is a cross-sectional end (plan) view of a single panel in one form; and

0026<figref idref="DRAWINGS">FIG. 10</figref> is an end view of a mandrel attachment to a panel in one form.

DETAILED DESCRIPTION

0027In one aspect, the disclosure herein provides a method for producing a composite structure. The method for manufacture, in one manner, may be accomplished in the field (also referred to as “onsite”), therefore reducing transportation costs of the structure from an offsite location to the field. Specifically, the structure in one form may be a support tower for a nacelle for wind power generation. The support towers, for example, may range from 100 ft. to 400 ft. Some such towers may include several unitary base or modular structures 50 ft. long (or longer). As the support towers for wind power generation increase in height, their base diameters substantially increase. As the base diameter of a tower increases beyond the convenient transportation range, such as diameters larger than 15 ft., transportation of the unitary sections becomes increasingly difficult. Thus, in one aspect, disclosed herein is a method for producing the unitary base structures comprising modular panels, and combining such unitary base structures to produce large structures, such as wind turbine towers. In one aspect, the unitary base structures may be conic sections (cylindrical or other suitable forms) as modular components, wherein the final assembly of the tower may be accomplished in the field. In another aspect, the tower may be a hybrid design. Other large structures, including, but not limited to, storage tanks, etc, may also be produced using the methods described herein.

0028<figref idref="DRAWINGS">FIG. 1A</figref> shows a line diagram of an exemplary tower <b>20</b> comprising a plurality of base structures in the form of conic sections <b>22</b>, with a top conic section <b>24</b> and a bottom conic section <b>26</b>. While the term “conic” sections is used, the term is also intended to include “cylindrical” or “substantially cylindrical” sections, wherein each may include, in one form, a tapered section at an end of the cylindrical section functioning as a reducer. Intermediate conic sections <b>23</b><i>a</i>, <b>23</b><i>b </i>. . . <b>23</b><i>n </i>may be connected or applied between the bottom conic section <b>26</b> and the top conic section <b>24</b> until the desired height is achieved. In one aspect, each conical section includes a number of longitudinally interconnected panels <b>25</b><i>a</i>, <b>25</b><i>b </i>. . . <b>25</b><i>m </i>and may further include desired reinforcements. In aspects, each conic section may be more that 12 ft. in diameter and more than 30 ft. in length. For ease in understanding the manufacturing process, the method of making tower <b>20</b> will be described as making several individual components, such as building individual panels, combining or integrating the individual panels to form conic sections, and combining the conic sections to form the tower structure <b>22</b>, as described in more detail in reference to <figref idref="DRAWINGS">FIGS. 2-12</figref>.

0029The exemplary tower <b>20</b> (<figref idref="DRAWINGS">FIG. 1A</figref>) includes an axis system <b>10</b> which generally comprises a radially outward axis <b>12</b>, a longitudinal axis <b>14</b> and a tangential (also referred to as circumferential) axis <b>16</b>. The tangential axis <b>16</b> scribes a circle around the longitudinal axis <b>14</b>. This axis system <b>10</b> is incorporated for ease of understanding only and is not intended to be limiting in any manner.

0030<figref idref="DRAWINGS">FIG. 1B</figref> shows an exemplary tower <b>20</b><i>b </i>comprising a hybrid design or construction. In one aspect, the tower <b>20</b><i>b </i>may include one or more composite conic sections and one or more metallic and/or alternate material sections. In a particular configuration, a lower portion <b>22</b><i>a </i>of the tower <b>20</b><i>b </i>may include a base structure that includes one or more conic sections, including a composite base conic section <b>26</b> and composite intermediate conic sections <b>23</b><i>n </i>and <b>23</b><i>m</i>. These composite sections may be joined at joint <b>27</b><i>a </i>with an upper portion <b>22</b><i>b </i>of the tower <b>20</b>. The upper section <b>22</b><i>b </i>may include individual sections, such as sections <b>28</b><i>a </i>and <b>28</b><i>b</i>, constructed with a suitable alternate material, such as carbon steel. In one aspect, such a hybrid design or approach allows the use of modular composite panel construction method, described in reference to <figref idref="DRAWINGS">FIGS. 2-12</figref>, for larger diameter conic sections, such as conic sections <b>23</b><i>n </i>and <b>26</b>, where transportation of such large sections becomes inconvenient or impossible. Where the upper tower sections, such as sections <b>28</b><i>a </i>and <b>28</b><i>b</i>, taper in diameter to sizes that are more practical to transport, traditional tower fabrication methods with alternate materials, such as carbon steel, may be employed and coupled at joint <b>27</b><i>a </i>to the lower composite tower section <b>22</b><i>a </i>via mechanical or other connections, including, but not limited to, a bolted flange during the onsite erection/assembly process.

0031<figref idref="DRAWINGS">FIG. 1C</figref> illustrates an exemplary offshore floating tower <b>20</b><i>c</i>, moored to the sea (or lake) floor via mooring lines <b>28</b>, that, in one aspect, includes a plurality of conic sections <b>22</b> as described in reference to <figref idref="DRAWINGS">FIG. 1A</figref>, including a composite top conic section <b>24</b> and composite intermediate conic sections <b>23</b><i>a</i>, <b>23</b><i>b </i>. . . <b>23</b><i>n </i>that will remain above the water-line <b>27</b><i>c </i>when the tower <b>20</b><i>c </i>is installed. Conic sections <b>23</b><i>o </i>through <b>23</b><i>z </i>and base cap <b>29</b> comprise the portion of the tower below the water-line and perform the buoyancy and ballasting functions of the floating tower. In one aspect, the conic sections <b>23</b><i>o</i>-<b>23</b><i>z </i>may be produced utilizing composite materials by the process described in <figref idref="DRAWINGS">FIGS. 2-12</figref> or with alternate materials suitable for use in the art of sub-surface off-shore platforms. The relatively lighter weight of composite materials compared to traditional metallic materials employed for the upper conic sections <b>24</b>, <b>23</b><i>a</i>, <b>23</b><i>b </i>. . . <b>23</b><i>n </i>can substantially decrease the amount of buoyant materials required to float the overall offshore tower <b>20</b><i>c </i>and components to be mounted proximate the top of the tower <b>22</b><i>c</i>, such as blades, gears and generators.

0032<figref idref="DRAWINGS">FIG. 2</figref> shows an exemplary panel <b>28</b> having an upper edge or side <b>30</b>, a lower edge or side <b>32</b> and tangential edges or longitudinal sides <b>34</b> and <b>36</b>. The longitudinal direction of the panel is shown by axis y-y, i.e. the direction between the upper and lower edges. In one form, the panel <b>28</b> comprises a core layer, which may be a solid and continuous layer. In form, the core layer is comprised of a unitary structure of closed cell foam. Other suitable core materials may also be utilized, including, but not limited to, cellulose materials, specifically wood, such as Balsa, that is commonly used in the art. This core layer, in one form, is formed as a solid, arcuate panel upon which composite layers are placed to add rigidity and to carry radial, compression, and tensional forces of the tower.

0033As described earlier in reference to <figref idref="DRAWINGS">FIG. 1A</figref>, several panels are coupled along their longitudinal sides to form each conic section. The edges of a panel, such as edges <b>34</b> and <b>36</b> of panel <b>28</b>, may be coupled to adjoining panels using many different joining methods and arrangements. <figref idref="DRAWINGS">FIG. 3A</figref> shows a half-lap joint that may be utilized for coupling panels to form a conic section. In one aspect, the half-lap joint comprises a cheek surface <b>38</b> and a shoulder surface <b>40</b>. The cheek and shoulder construction tends to ease the manufacture of each conic section and therefore would ease construction of the tower <b>20</b> (<figref idref="DRAWINGS">FIG. 1</figref>) as a whole. The shoulder surfaces <b>40</b> and cheek surfaces <b>38</b> of adjoining panels <b>42</b> and <b>44</b> are shown. These surfaces would normally be coated with an adhesive prior to assembly. Also shown is the core layer <b>46</b> that in this application is sandwiched between an inner composite layer <b>48</b> and an outer composite layer <b>50</b>. To join or couple panels <b>42</b> and <b>44</b> along their respective longitudinal sides, resin or epoxy is normally applied to such surfaces and then shoulder surface <b>40</b> is placed on the cheek surface <b>38</b>. The epoxy is then cured to bond the cheek and shoulder surfaces. The assembled or coupled panels <b>42</b> and <b>44</b> are shown in <figref idref="DRAWINGS">FIG. 3B</figref>. An outer, circumferentially-oriented layer <b>52</b> is also shown in this cross sectional view. In one aspect, such an outer layer is applied after joining all the panels as described in more detail in reference to <figref idref="DRAWINGS">FIGS. 4A and 4B</figref>.

0034<figref idref="DRAWINGS">FIG. 3C</figref> shows a double half-lap joint (also referred herein as a full-lap joint) that may be utilized for coupling panels to form a conic section or to join a unitary conic section to an adjacent unitary conic section. In one aspect, the full-lap joint comprises a cheek surface <b>38</b><i>a </i>and a shoulder surface <b>40</b><i>a </i>on one panel <b>42</b><i>a </i>and cheek surface <b>38</b><i>b </i>and a shoulder surface <b>40</b><i>b </i>on an adjoining panel <b>42</b><i>b</i>. In this configuration, the shoulder surface <b>40</b><i>b </i>of panel <b>42</b><i>b </i>is placed on the cheek surface <b>38</b><i>a </i>of panel <b>42</b><i>a</i>, while simultaneously the shoulder surface <b>40</b><i>a </i>of the panel <b>42</b><i>a </i>is placed on the cheek surface <b>38</b><i>b </i>of panel <b>42</b><i>b </i>to join the panels <b>42</b><i>a </i>and <b>42</b><i>b </i>along their respective longitudinal axes. The surfaces <b>38</b><i>a</i>, <b>38</b><i>b</i>, <b>40</b><i>a </i>and <b>40</b><i>b </i>are coated with a suitable adhesive prior to joining such surfaces. The adhesive is then cured to bond the panels <b>42</b><i>a </i>and <b>42</b><i>b </i>along their longitudinal sides. The joined or coupled panels <b>42</b><i>a </i>and <b>42</b><i>b </i>are shown in <figref idref="DRAWINGS">FIG. 3D</figref>. An outer, circumferentially-oriented layer <b>52</b><i>a </i>is also shown in this cross sectional view. In one aspect, such an outer layer is applied after joining all the panels as described in more detail in reference to <figref idref="DRAWINGS">FIGS. 4A and 4B</figref>.

0035<figref idref="DRAWINGS">FIG. 4A</figref> shows an exemplary manner of joining various panels to form a conic section, according to one embodiment of the disclosure. <figref idref="DRAWINGS">FIG. 4A</figref> shows a mandrel <b>53</b> dimensioned to form a selected conical section using panels described herein. In one aspect, the mandrel <b>53</b> includes a bulkhead <b>57</b> and a number of longitudinal and radial spokes <b>55</b>. The mandrel <b>53</b> has an axis system <b>10</b> that includes a longitudinal axis <b>14</b>, a radial axis <b>12</b> and a tangential axis <b>16</b>. The bulk head <b>57</b>, spokes <b>55</b> and the core panels define the mandrel system in normal operation. The term mandrel is used herein to indicate the portion to which the core panels are temporarily affixed. <figref idref="DRAWINGS">FIG. 4A</figref> illustrates how the adjoining panels <b>42</b>, <b>44</b> and other panels are mounted on a mandrel <b>53</b>. An attachment bracket, such as shown in <figref idref="DRAWINGS">FIG. 10</figref> is one example of a method to attach the panels <b>42</b>, <b>43</b>, etc. to the mandrel <b>53</b> to facilitate winding the substantially circumferentially aligned panels as described in reference to <figref idref="DRAWINGS">FIG. 4B</figref>. The panels <b>42</b>, <b>44</b>, etc. are placed longitudinally along the longitudinal axis <b>14</b> of the mandrel <b>53</b>. The panels are coupled or joined together around the mandrel <b>53</b> to form a base enclosure or a base structure. The adjoining panels on the mandrel <b>53</b> may be joined in any suitable manner, including the manners described in reference to <figref idref="DRAWINGS">FIGS. 3A and 3B</figref> or <b>3</b>C and <b>3</b>D.

0036Once the individual panels are placed upon the mandrel <b>53</b>, as shown in <figref idref="DRAWINGS">FIG. 4A</figref>, the entire mandrel <b>53</b> is rotated about the axis <b>14</b> in direction <b>72</b> as shown in <figref idref="DRAWINGS">FIG. 4B</figref> whereupon a layer of circumferential fibers <b>70</b> are disposed on the surface of the panels. In one form, the circumferential fibers <b>70</b> are wound off a plurality of spools <b>74</b> and through a resin bath <b>76</b>. While the process of <figref idref="DRAWINGS">FIG. 4B</figref> shows three fibers being wound at one time, more or fewer fibers may be wound simultaneously. As the fibers are wound onto the panels <b>42</b>, the bath/spool assembly <b>78</b> moves longitudinally along directions of travel <b>80</b> and <b>82</b>. In one form, the bath/spool assembly <b>78</b> is slaved to the mandrel <b>53</b> rotation either electronically or mechanically, such that the distance of longitudinal travel <b>80</b>-<b>82</b> corresponds to the degree of rotation of the mandrel <b>53</b>. In one aspect, this step is accomplished onsite, as a single mandrel <b>53</b> is capable of producing an unlimited supply of conic sections for one or more towers. Thus, the completed conic sections <b>22</b> (<figref idref="DRAWINGS">FIG. 1A</figref>) require very little transportation expense, as they can be formed onsite from the individual panels <b>42</b>.

0037Once the base section <b>26</b> (<figref idref="DRAWINGS">FIG. 1A</figref>) is completed, it may be placed in an upright position and fastened to and/or embedded in a structural base member, such as a concrete pad. The longitudinally upward edge <b>54</b> (<figref idref="DRAWINGS">FIG. 4A</figref>) of each section <b>22</b> (except the top section <b>24</b>) comprises an attachment joint to the succeeding section. The bottom edge, in one form, as previously disclosed, may utilize a half-lap type, or double half-lap type joint that includes a cheek <b>56</b> and shoulder <b>58</b> shown in <figref idref="DRAWINGS">FIGS. 5A</figref> and <b>5</b>B. The upper section to be installed comprises a mating joint, of opposite configuration to the adjoining lower section. Prior to adjoining the upper and lower sections, adhesive may be applied to the adjoining cheek and should surfaces. The top section <b>24</b> would in one form comprise a joint operatively configured to facilitate attachment of a top cover, nacelle, or other structure via any suitable mechanism, including, but not limited to, a bolted flange.

0038Also shown in <figref idref="DRAWINGS">FIG. 5A</figref> is a butt and strap joint <b>59</b> that substantially comprises a layer or multiple layers of a suitable material, which overlaps adjoining sections <b>88</b> and <b>90</b> to transfer forces (such as, tensile, compressive and/or torsional forces) between the section <b>88</b> and section <b>90</b>.

0039In another form, internal hoop bands <b>84</b> and external hoop bands <b>86</b> may be utilized to transfer forces between adjoining sections, as shown in <figref idref="DRAWINGS">FIG. 5B</figref>. The hoop bands may include a layer or multiple layers of material that overlap adjoining sections. In one aspect, the hoop bands may be substantially rigid, cylindrical or partial cylindrical members that are formed (or pre-formed) to fit an outer surface of a conic section joint, such as a joint <b>27</b><i>a </i>between conic section <b>23</b><i>a </i>and <b>23</b><i>b </i>(<figref idref="DRAWINGS">FIG. 1A</figref>) and then attached via adhesive. Both the butt and strap joint, and the hoop bands function to transfer forces (such as: tensile, compressive and/or torsional) between one section <b>88</b> to the adjoining section <b>90</b>.

0040<figref idref="DRAWINGS">FIG. 6</figref> shows a plan cutaway view of another embodiment of a panel <b>66</b> comprising a plurality of core cells <b>56</b> that may be longitudinally aligned, extending substantially the length of the panel <b>66</b> as shown in <figref idref="DRAWINGS">FIG. 7</figref>. Alternatively, the core cells <b>56</b> may be arranged in a grid or a matrix form, such as shown in <figref idref="DRAWINGS">FIG. 8</figref>. Individual cells <b>56</b> (<figref idref="DRAWINGS">FIGS. 6</figref>, <b>7</b> &amp; <b>8</b>) may be interconnected by a glass/resin layer <b>58</b> for reinforcement. In one form, a resin transfer line <b>60</b> (<figref idref="DRAWINGS">FIG. 6</figref>) may be utilized between core cells <b>56</b> to facilitate injection of a resin into the glass/resin layer <b>58</b> (<figref idref="DRAWINGS">FIG. 6</figref>). The panel <b>60</b> is shown to also include an inner layer <b>48</b> and an inner layer <b>50</b>.

0041Upon the inner layer <b>48</b> and the outer layer <b>50</b> (<figref idref="DRAWINGS">FIGS. 6 and 9</figref>) a reinforcing layer, such layer <b>59</b><i>a </i>on layer <b>48</b> and layer <b>59</b><i>b </i>on layer <b>50</b> may be applied. In one aspect, the reinforcing layers <b>59</b><i>a </i>and <b>59</b><i>b </i>may comprise fiberglass or other suitable material. In one aspect, layers <b>59</b><i>a </i>and <b>59</b><i>b </i>comprise substantially longitudinally aligned fibers <b>65</b>. (<figref idref="DRAWINGS">FIGS. 6 and 9</figref>) By incorporating the substantially longitudinally aligned fibers <b>65</b> adjacent to the inner and outer layers <b>48</b> and <b>50</b>. The laminate within a completed panel, such as panel <b>42</b> (<figref idref="DRAWINGS">FIG. 2</figref>) utilizing the structure shown in <figref idref="DRAWINGS">FIG. 6</figref> will exhibit substantially higher axial strength and stiffness to resist the large lateral forces and overturning bending moments present in the wind turbine towers. Individual panels, such as panels <b>42</b> (<figref idref="DRAWINGS">FIG. 2</figref>) may be produced offsite, such as at a manufacturing plant, wherein laminations can be manufactured relatively easily and with high degree of quality control. The individual panels <b>42</b> (<figref idref="DRAWINGS">FIG. 2</figref>) may then be transported to an onsite location and mounted onto the mandrel <b>53</b> (<figref idref="DRAWINGS">FIG. 4A</figref>) to make an individual conic section as shown in <figref idref="DRAWINGS">FIG. 4B</figref> that might otherwise be too large in diameter for efficient transport, such as via a truck, from an offsite location to an onsite location.

0042<figref idref="DRAWINGS">FIG. 9</figref> shows a cross section of the outer surface of a completed panel comprising a plurality of core cells <b>56</b>, inner layer <b>48</b>, outer layer <b>50</b>, and reinforcing layers <b>59</b><i>a </i>and <b>59</b><i>b </i>comprising substantially longitudinally aligned fibers, and reinforcing layer <b>52</b> comprising substantially circumferentially aligned fibers. The glass/resin reinforcement layers <b>58</b> are also shown for clarity. In one form, the core cells <b>56</b> with the inner layer <b>48</b> and outer layer <b>50</b> are produced using the methods described in U.S. Pat. Nos. 5,462,623 filed Oct. 31, 1995 “Method of Production of Reinforced Foam Cores”, 5,589,243 filed Dec. 31, 1996 “Reinforced Foam Cores and Method and Apparatus of Production”, 5,834,082 filed Nov. 10, 1998 “Reinforced Foam Cores and Method and Apparatus of Production”, 6,740,381 filed May 25, 2004 “Fiber Reinforced Composite Cores and Panels”, 7,393,577 filed Jul. 1, 2008 “Fiber Reinforced Composite Cores and Panels” each incorporated fully herein by reference. It should be noted that the various dimensions given herein are for explanation purposes only and are not intended to limit the claims in any manner.

0043For the purpose of this disclosure, the term offsite means a facility distant from the location of placing or erecting large structures, such as a manufacturing or an assembly facility. The term onsite means a place or facility from where conic sections made according to the disclosure herein may be easily transported to the location where the finished large structure is to be placed or erected. With respect to the land-based wind turbine towers, an onsite facility may be located near the place of the tower erection. In such cases, the conic sections may be made and formed into the tower without resorting to transportation of the conical sections over normal roads, highways etc that are not conducive to the transportation of such large structures. For off-shore wind turbine towers, an onsite facility may be located on a waterway or convenient port location from which conic sections are fabricated and potentially erected into full towers prior to deployment offshore.

0044Thus, in one aspect the disclosure herein provides a method of making a selected structure, which method in one embodiment includes: providing a plurality of members, each member comprising a composite material and configured to be coupled to at least one other member along a longitudinal side thereof; coupling onsite the plurality of members along their respective longitudinal sides to form a base enclosure; reinforcing onsite the base enclosure with a composite material to form the selected structure. In another aspect, the method further includes placing the plurality of members on a mandrel before coupling onsite the plurality of members. In one aspect, reinforcing onsite the base structure may be accomplished by placing composite fibers and a resin around the base enclosure and then curing the resin to form a unified structure. In another aspect, providing the plurality of members may include making each such member using a process that includes: providing a core member; reinforcing the core member with composite fibers substantially along a longitudinal direction of the core member; and applying and curing a resin on the composite fibers. In one aspect, the panels may be interconnected using any suitable method, including using a half-lap joint, and a double half-lap joint.

0045In another aspect, the disclosure provides a structure, such as a tower, which in one embodiment may include: a plurality of serially connected conic sections, wherein at least one conic section includes a base section that includes a plurality of longitudinally interconnected panels and a composite material layer around the base section. In another aspect, the tower may further include a band around a joint between the at least one conic section and an adjoining conic section configured to provide a reinforcement at the joint. In one configuration, the tower includes an upper section comprising one or more metallic conic sections and a lower section comprising the at least one conic section. In another configuration, the tower includes a lower section that includes one or more conic sections made from a material suitable for placement under water and wherein the lower section is further configured to be moored to a sea bed. In one aspect, the conic sections may be connected to each other by a half-lap joint or a double half-lap joint.

0046While the present disclosure is illustrated by description of several embodiments and while the illustrative embodiments are described in detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications within the scope of the appended claims will readily appear to those of ordinary skilled in the art. The disclosure in its broader aspects is therefore not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of general concepts described herein.