WO2011054975A1

WO2011054975A1 - Lightweight housing for movable structures

Info

Publication number: WO2011054975A1
Application number: PCT/EP2010/067152
Authority: WO
Inventors: Jacques Ladyjensky
Original assignee: Continental Structures Sprl
Priority date: 2009-11-09
Filing date: 2010-11-09
Publication date: 2011-05-12
Also published as: BE1019731A3

Abstract

The invention relates to a method for constructing a lightweight housing for a movable or transportable element, consisting in making a cage-shaped mesh network, from a flexible cord of preferably carbon fibers, which have been impregnated with a synthetic resin capable of subsequently hardening. The cord, which is of a large length, is draped around a template having the shape of the future housing, which template is topped with a large number of threaded rods perpendicular to the surface of the template, each of same being placed at the location of one of the nodes of the future network. The flexible cord is positioned while looping around the threaded rods. Each node comprises an even number of branches, i.e., each time there is an arriving and a departing cord branch. Thus, there is a certain cluster of material which forms at the base of each threaded rod, which is then crushed by the screwing down of a nut with a washer, and which, after hardening, will form a particularly rigid and solid node.

Description

Lightweight carcass for mobile structures

The present invention relates to carcasses of

relatively large mobile structures, ie carcasses whose largest dimension substantially exceeds the height of a human being. Two typical applications are more particularly envisaged: automobile bodies, and wind turbine blades. It is becoming more and more certain that lightness without loss of strength is an important requirement for structures of this kind. The arrival of new materials such as high-strength fibers, and

especially carbon fibers, very light, allows advances on this subject. However, these materials are expensive, and their implementation can be too. It is common, in fact, that we must first weave them, then dispose the resulting textiles in molds at a high cost, then, given the relatively large dimensions of the objects here

considered, it is by hand that these textiles are arranged and then impregnated with synthetic resin.

Another known method consists of an operation of

pultrusion followed by filament winding (filament

inding). A bead of associated fibers is then run in parallel, a small diameter bead - less than 6.35 mm - in a bath of impregnating resin, then pulled through a spinning die, and then wraps around a mandrel under high tension. The object obtained can be large, and the process would be economical, if the investment in equipment was high. Moreover, and this is undoubtedly its main limitation, this process does not

SUBSTITUTE SHEET (RULE 26) applies only to manufacture articles of revolution. Moreover, it is also known that cords and pultruded can be assembled parallel to each other, undergo compression which compact them transversely in appropriate molds, and thus become linear profiles.

In the present invention, it is proposed to construct large objects in the form of cages, or

in other words, carcasses affecting the shape of a cage. By employing the word carcass, it is suggested that the resulting structure should in the following preferably be coated with a skin or any other surface that encloses the volume represented by the carcass. It is also proposed to use pultruded cord, such as the one mentioned above, but of larger section than winding

filamentary - for example between 5 and 10 mm in diameter - and to make a cage by draping it on or in a suitable template, making it go back and forth with

crosses, in order to obtain a meshed network with nodes.

The method of constructing a cage-like carcass with subsequent interfacing has already been employed in the past when it was imperative to obtain structures of great lightness. Thus the main hull or cabin of the planes of the First World War consisted of a cage made of wooden beams, which were then covered by surrounding it with a particularly strong fabric. The required lightness was obtained, but the materials used were fragile and unsustainable. The concept of a cage-like carcass suggests that we are concerned about obtaining an enclosure made up of a mesh network, based on interwoven linear elements, forming together a surface closed on itself, or almost, and which encloses a certain interior volume. It should be added that linear elements may not be part of the surface mesh network, and pass through the enclosure volume, to reach the opposite surface: we can call them braces, or spacers. These additional linear elements contribute to the stiffening of the assembly, and they can also be used for welcome uses within the volume of the carcass, such as seats or luggage racks. It was not denied to use in the carcasses of aircraft cabins mentioned above.

More recently, the document WO 01/14128A1 discloses a "nodal structures" method, or structures with nodes, in which a structure for a vehicle is used, based on the use of fibers, preferably carbon, which is has a cage-shaped mold. These fibers are preferably in the form of a hollow braid enclosing a core of synthetic foam, the whole braided fiber plus core thus constituting a linear element having in itself a certain rigidity after hardening of the resin

impregnation. The way to form the nodes of the cage appears in the description. They are constituted in a completely different way than in the method of the present invention, which precisely relates to the way of constituting the nodes of the cage.

Furthermore, a German invention that is the subject of the patent application DE 40 02 874 A1 claims a carcass in the form of a cage for an automobile, characterized by the presence of two reinforcing triangles, one at the front and one in the back. The way to build the nodes is not described.

The present invention proposes a new technique for the constitution of the nodes. The invention thus refers to the known technique of a cage-shaped carcass by using linear elements in the form of a long cord that is draped around a template or in a mold, so as to what it constitutes a mesh network, and the novelty

consists in the way of constituting the nodes. These are obtained by ensuring that the bead used is very long, and that each node, this cord at least partially bypasses an ankle belonging to the jig or mold, and thanks to which a weld "cord on cord "can be obtained. A first object of the invention is to obtain good rigidity of the entire carcass. Parallel fiber cords have a remarkable tensile strength; but, with respect to other efforts, especially transversal or torsion, they behave less well. The method claimed here appropriately blocks any hinge effect at each of the nodes. These are indeformable by constitution. Moreover, the materials used, in particular the carbon fibers, have a very high capacity of energy absorption to shock (anticrash) but this capacity is only properly exerted

reaching their break, rather than by an effect of

deformation (case of springs). It is therefore appreciated that there is no hinge effect at the nodes.

A second object of the invention is to obtain a carcass of very low cost. If the materials used are of a certain price, on the other hand the confection she herself is very fast here, even without mechanization. In an example described below, a single man can make a vehicle carcass in just over a day's work. A third object of the invention is to obtain a great lightness, because of the simplicity of each node. In our time, mass savings play an important role in mobile structures.

A fourth object of the invention is to facilitate the method of attachment of the trim elements intended to surround the carcass. These may be sheets or panels, thermoformed, or obtained by other molding methods, or, canvas, elastic or not. The presence of a hole in the center of each node, as a result of the method employed, allows very effective attachment modes.

More specifically, the claimed process

consists of making a cage from a bead of high strength parallel fibers, for example carbon fibers, which was impregnated with synthetic resin by pultrusion, that is to say by passing through the resin bath followed traction through a spinning die. This cord, compared to that used in winding

The filament winding is of greater section, preferably between 5 and 10 mm in diameter, which is a maximum for proper impregnation. The cord can be draped, by hand, around a template that has the shape of the volume that will enclose the future carcass, or, it is draped inside and against the wall of a mold which is equivalent thereto . The template is convex; the mold is concave. The cord is arranged in a suitable path, predetermined or not, with comings and goings with many crossings, so as to form a mesh network. It is important for the cord to be one piece over a very long length and preferably one piece for the entire length of the draping. The way to make the nodes, - the places where the bead elements constituting the mesh network intersect - is described below and characterizes the novelty of the process.

According to one embodiment of the method of the invention, at each node position, the template, or the mold, comprises a threaded rod attached thereto, perpendicular to the plane tangent to the envelope of the volume determined by said template, or the mold. To constitute the knot, the stem is bypassed by the bead - which bead is always stretched or pressed against the surface of the jig or mold - so as to operate preferably at least one

fifth of a turn or at most one and a quarter turn, before continuing the laying of the cord to the next knot. Then when the moment has arrived for the cord to return to the node that has just been mentioned, to meet, by crossing it, the cord element that is already present, we bypass again and in the same way, with the bead element held at the moment, the same threaded rod. Then, a nut with washer is placed on the threaded rod and it is tightened until a crushing of the knot, sufficient to ensure a self-welding of the two elements of cord between them. In order to guarantee this good self-welding, care will have been taken, preferably, to incorporate a high adhesion product with the ordinary impregnating resin used during the pultrusion. It thus forms at the foot of each threaded rod a certain mass of material crushed by screwing a nut with washer, to form after hardening a particularly rigid and solid knot.

The cord leaving the newly formed knot is directed, in most cases, following the outer surface of the convex jig (or inner concave mold) to the next adjacent knot by the shortest path. Nevertheless, it is also possible to force the cord to leave said surface and to drive it through the interior of the volume to a distant node, where it will also be knotted and tightened in the manner described above. If necessary, if the distance to travel requires, we will use a support - later removable - which supports the cord, at least partially, along its passage of the mold. These cord elements, which we can call

through, are intended to play the role of

bracing to enhance the rigidity of the carcass. They may also play the role - particularly in the case of a vehicle carcass - of seats for seats, for luggage boxes or other similar role. A four-node node has been described in the foregoing

branches, for example in the form of a cross. However, in the same way, we can return to this node again with a section of the cord that will then leave to get two more branches. The bypass, then the final screwing, will be the same way. The knot will simply be thicker. You can also make a node with two branches, a newcomer and a starter. There will always be an even number of branches to consider. If the design of the structure requires that a node has an odd number of branches, it will be necessary to have two cords against each other, or one on the other, at least until the next node. After the completion of the draping using the entire length of the cord, the assembly including the template (or mold) is set to harden per stay in a temperature chamber

appropriate. The demolding is then carried out, separating the carcass from the template, or from the mold, which may, if necessary, have been constructed in an easily dismountable manner, in particular if the volume of carcass to be obtained is complicated. Threaded rods must be removable.

The washer that has been mentioned above between the nut and the node, should preferably be of non-adhesive material such as PTFE. It is also advantageous to place a washer of non-adhesive material between the knot and the surface of the jig (or mold).

Washers may not be simple flat washers. They may also have been designed to give the knot an appropriate shape under the action of clamping pressure. They serve as a kind of mold for the outer and inner surfaces respectively of the node.

The jigs and molds used for the process of the invention, whether removable or not, are

very simple and simple to use: they are not required for effort, resistance to molding pressure or surface finish requirements.

A serious factor of economy also lies in the speed of execution and more precisely in the speed with which one passes with the cord, from one node to the next at the cost of a simple bypass, without special precision. In particular, it avoids a knotting operation similar to that encountered in knitting (one of the manners commonly used in other contexts, in particular textile, to create a mesh network, such as a net, from strands flexible). Here, the knot is formed in a solid manner, without need of interlacing, by the simple combination of an adhesion between them cords, copolymerization under high local pressure, and preferably under cooking. According to a practical aspect, the rapid formation of the knot by simply bypassing the ankle or threaded rod, allows to simply leave on the ground, during work, the

length of the cord waiting for its turn to be used, length that can reach a hundred meters. It is indeed preferable, as already mentioned, for the solidity of the carcass, that the cord is of a single coming without interruption, and in particular without interruption at a node. It would lead to a decrease in the mechanical strength of the assembly, in particular to shocks. With a pack of 100 meters cord to handle, the operator could not consider doing a knot with knitting as knit.

The use of a concave mold instead of a convex jig has only one drawback, that of costing a little more, but has undeniable advantages. This allows the nodes to be shaped, according to their outer face, in the alignment of the cord strands themselves, so not to present protrusion that can interfere

subsequently the laying of the outer skin. Then, if several cord crossings succeed in the same place (multi-branch node), the nodes stack one on the other towards the inside of the structure which is less troublesome. Finally, only the operation inside a mold allows easy installation of the support structure of the molds.

braces already mentioned.

The present invention will be better understood on reading the following description, given as a illustrative only, with reference to the accompanying figures in which: FIG. 1 is a perspective view of a carcass according to the invention, adapted to a motor vehicle of small size, Fig.2 shows, in perspective, the pace that would have the carcass of FIG. 1 after its dressing, the flanks of the carcass having for example been covered with a fabric

elastic, and the top capped with a transparent dome, Fig.3 shows a perspective view of a vertical wind turbine sketch of Savonius type which is based on a carcass according to the invention, Fig.4 is a view in perspective of a sketch according to FIG. 3 showing the carcass in question, FIG. 5 is a perspective view of a convex jig element, provided with a threaded rod at the location of each of the future nodes, FIG. 6 is a perspective view, exploded, of one of the ways of forming a knot with the cord, against the surface of a convex jig, Fig.7 relates to another way of forming such a knot, Fig.8 relates to yet another way of 9 is an exploded perspective view of an example of forming a knot against the surface

concave mold, Fig. 10 is a perspective view of a concave mold fragment having a cross-cord support member, here interrupted for clarity of the drawing; Fig. 11 is an exploded perspective view of an example Figure 12 shows the plan view of a brace obtained by so-called bead elements.

Referring to FIG. 1 shows how a carcass 2 can be constituted by means of a flexible cord 1 which has reciprocations along a relatively complicated path so as to form a mesh network comprising several tens of nodes such as 3, 4, 5, 6, 7, 8, 9, 10 and 11.

On this carcass, after hardening of the flexible cord, it will be possible to deposit one or more coatings that will be attached to the nodes, so as to obtain a waterproof covering, which can take the appearance shown in FIG. This is an example illustrating a possibility of obtaining a small vehicle to a place, provided with a door remaining open. The top of the carcass is capped with a cupola 13, a part (with a cutout for the top of the door), transparent, for example polymethylmethacrylate, attached to the nodes of the carcass. The flanks of the carcass are for example dressed with an elastic fabric also in one piece and also attached to the knots of the carcass.

In FIG. 5, it can be seen how the cord 1, of great length, is deposited on the surface of a convex jig 14 provided with a large number of threaded rods 15, each disposed perpendicular to the surface of the jig and attached in a removable manner. The template has the shape of the future carcass to build. Each of these threaded rods 15 will become the center of a node such as 17, 18 or 19. The cord goes from one node to another, bypassing each time the corresponding threaded rod, and thus forms a network with crosses, at each node, the cord with itself. We understand that each node therefore corresponds to an even number of branches. The node 17 is six branches, the node 18, four branches, the node 19, six branches, but as the design provided for the network, requires at this location a node with five branches, it has arranged two branches parallel coast next to each other, according to 20.

In Fig. 6, which is an exploded view, before any tightening of the nut, it is possible to examine how a four-pointed knot is made. A cord element 1 bypasses the threaded rod three-quarters of a turn, and another cord element 1, during its "return" path, also bypasses the same threaded rod, numbered 21. In 14, there has been a fragment of the template, here convex. By tightening the nut 23, the washer 22 will crush the flexible cord elements 1 very forcefully. After hardening under said compression, these cord elements 1 will be self-welded together. It is good, in order to facilitate demolding, that the washer 22 is of non-stick material, such as PTFE. And also that the surface of the jig 14 is coated, for the same reason, with a release layer.

The flexible cord 1, of great length, is constituted in the following manner. It comprises several hundreds of thousands of fibers with high tensile strength, preferably carbon fibers, parallel aligned side by side. It is passed through a bath of synthetic resin which can subsequently harden by polymerization and then through a die intended to wring out any excess resin, since there is an optimum proportion to be respected between the fiber weight and the resin weight. This method of obtaining a bead is known as

"Pultrusion". In the present process, so

preferentially, it gives the pultruded cord a twisting on itself, longitudinally, so as to give it a very useful body to allow its handling by hand during the draping around the template. In order to increase the strength of the self-welding, it is good to have provided for the incorporation in the impregnating resin of a chemical element reinforcing resin-resin adhesion after contact. This chemical may also have the consistency of a varnish that will be applied continuously to the outer surface of the bead, during its manufacture in the terminal phase, before or after twisting. The chemical compound may be an epoxy resin, for example a Sicomin SR8150 epoxy resin, for example 10%. It is essential that the cord is very long compared to the length of a branch of the network, and especially that it is never interrupted to the right of a node. The continuity of the fibers at the crossing of a node plays a key role for the strength and rigidity of the carcass obtained after curing the assembly.

Figs. 7 and 8 receive the same comment as above: they relate respectively to nodes with six and three branches, instead of four.

Figs. 9, 10, and 11 refer to the case where the bead is draped, not on the outside of a convex jig as described above, but against the inner surface of a concave mold. They receive the same comment as above about how to form the knot. The advantage of the use of a concave mold with respect to the use of a convex jig is that the outside of the carcass has a continuity of alignment of the branches of the network and the nodes heads. These heads are not likely to protrude outward, as may be the case with

the use of a template of convex shape outside which is practiced draping. But the making of a removable concave mold is more expensive than that of a convex jig, removable or not. Nevertheless, in both cases, these assemblies are low cost, because the process does not involve the exercise of effort or pressure on the carcass during manufacture. Cheap and easy to use materials can be used for both templates and molds such as wood, cement, polyester etc. It must be ensured that the threaded rods are removable. The washer 22, in Figs. 9, 10, and 11 is advantageously designed with a concavity parallel to the concavity of the mold.

It is understood that during the draping of the cord against the surface of the template, or mold, it must be ensured that there is permanent contact between the cord and said surface, otherwise the carcass will not respect the we want to give it. This contact can be ensured by simple gravity in the areas where the thing lends itself. Elsewhere it will be good to provide very simple temporary fasteners, for example in the form of small spring clips, one every cord decimetres, for example.

The demolding with disassembly will take place after hardening, or allowing to harden, the impregnating resin of cord. This can be done either by placing the assembly not yet removed from the mold in a furnace providing polymerization at low temperature, generally below 100 ° C. By studying certain resin formulations, it is possible, if necessary, to obtain a polymerization at room temperature, but then at the cost of a certain duration, with longer immobilization of the mold. The use of a furnace makes it possible to devote one day of work to the draping, then one night to the hot polymerization, thus freeing the mold for the following day.

After demolding, each node is automatically provided with a central hole, the diameter that had the threaded rod. These central holes are very effective in

fastening of any covering element around the carcass. Fig. 10 shows, at 25, the departure of a support element for "through cord". This element 25 does not come in continuity with the surface of the mold, - it leaves this surface to move inwardly of the volume enclosed by the mold, until reaching the opposite surface. On this support element, the appropriate branch of the flexible cord 1 will be deposited. To allow subsequent demolding, the support member 25 must be detachable from the rest of the mold. In fig. 1, there is illustrated according to 12 a through bead element, which joins together the left flank and the right side of the carcass, playing a bracing role. On the same figure, is also illustrated a more elaborate bracing, according to 3, 4, 5, 6, 7. Here this assembly, in addition to role of bracing, can also play in the future vehicle a supporting role for a seat, or for a luggage area. In Fig.12, it can be seen, seen in plan, the configuration of this brace, which brings together the nodes 3, 4, 6 and 7. These four nodes are here schematically indicated in 26. In the center of

bracing, there is no knot, but a ligature between the branches coming from the four corners of the

bracing, which intersect at this location, - ligation carried out according to the methods used in basketry. As ligation filament, preferably a bead of very thin diameter, of the order of 2 mm for example, also obtained by pultrusion carbon fiber and impregnating resin. At other places in the carcass, it is of course also possible to make use of this kind of ligation technique inherited from conventional basketry processes.

Manufacture of a prototype.

A single-seat small vehicle carcass having the appearance illustrated in FIG. 1, length 2.25 m, width 0.9 m, height (for the carcass only) 1.3 m. We used a concave draping mold, removable,

made of polyester-fiberglass laminate, using a metal model on which the

laminate is directly molded. This metal model was made by means of brass tubes 8 mm in diameter, bent and assembled to obtain faithfully the shape of the desired mesh network. The nodes are 200 in number.

The 100 threaded rods, of 6 mm metric, are removably attached to the concave mold, and directed towards the inside thereof. Their length is 80 mm. PTFE sheath surrounds them to prevent undesirable adhesion after demolding. The washers, with a diameter of 25 mm, have a concavity similar to that of the mold at the relevant location, without great precision being necessary for this concordance. They are lined with anti-stick PTFE. The inside of the mold is also coated with a non-stick PTFE varnish.

An 8 mm diameter bead, made of about 400,000 parallel carbon fibers, was made from about fifty coils to a pultrusion machine. The length of the pultruded cord is about 100 meters. At the output of the pultrusion machine, the cord is twisted longitudinally on itself with a pitch of 150 mm. For this purpose a rotary device has been used in which is mounted the traction puller of the pultrusion. In the pultrusion bath was poured a Sicomin 8500 epoxy resin, catalyzed beforehand to give a predictable working time (pot life) of five hours. The cord remains flexible during this time. The

proportion fiber resin is of the order of 50%. Once the spinning die of diameter fixed - here 8 mm - one adjusts the proportion in question by adjusting the number of intervening fiber coils.

The bead is deposited on the surface of the concave mold, in a suitable path, predetermined or not, drawn on said surface beforehand. Each of the 100 threaded rods is bypassed, and this on average twice per rod, since on average there are four branches per node. All of these laying and bypassing operations take about four hours, for the main operator. A helper ensures that the cords stay in contact with the surface of the mold, and also ensures the tightening of the nuts and washers. The set molds more cords is then rolled in an oven at a temperature of 65 ° C, where it remains overnight. The next day, the mold is removed, with the mold and associated rods removed, after which we can start the operations for a new part.

As will be understood by those skilled in the art, partial or complete automation of the process according to the invention is possible.

The carcass obtained, thanks to the monolithic nature of the knots, is very rigid. It is however less rigid than if one manufactured it in metal. But the weight obtained is very advantageous: of the order of 8 kg. This excellent value obviously comes from the low density of carbon fibers (1,6) and resin (1,2) but also because at each of the 100 knot welds, there is no input material .

As mentioned with respect to a metallic execution, the rigidity obtained is generally less. The resulting relative elasticity has both advantages and disadvantages. A disadvantage lies in a certain dimensional imprecision, inaccuracy also coming from the nature of the process itself. This is how for the

prototype that is described here, we may have to give up a door that can close. Indeed it implies the use of hinges and locks, demanding a certain dimensional accuracy. But the advantages of a certain elasticity with respect to the metal, are undeniable, notably in the form of an excellent resistance to

collisions. There was also an increased feeling of comfort when driving, as the seat structure is part of the carcass according to the invention. In this respect, the benefits outweigh the disadvantages.

Each of the nodes, after demolding, has a hole 8 mm in diameter. These holes provide a very effective way of hooking up the exterior trim of the vehicle. Just pass a bolt or rivet. It is not necessary to use all the 100 holes according to the example described.

In the case of the prototype described here, the cladding can be very thin, since the carcass is sufficient to take up the stresses, and the structure of said carcass gives all the shape details of the vehicle. The upper part consists of a cupola of polymethyl methacrylate, of rubbery, transparent type,

1.5 mm thick, thermoformed, one-piece, bolted to the carcass in multiple locations. This bolting allows, on the one hand, the use of a metacrylate sheet of minimal thickness, and on the other hand, the cutting of the door top out of the dome after thermoforming. The sidewalls can be made of light, opaque rubberized fabric, secured by riveting or bolting, or thermoformed panels, like the dome

above. The material used for these molded panels would then be ABS or a derivative resin, in thickness of the order of 2 mm. Preliminary tests have demonstrated excellent resistance of the structure to shocks such as they can be encountered in the reality of road traffic, for speeds of the order of those that the vehicle in question may extinguish, about 45 km / h. In places, ligatures can be used according to well known techniques of conventional basketry. As ligating strand, pultruded cord similar to that described above was used, but of diameter 2 mm instead of 8.

Claims

Claims.

1) A method of constructing a light carcass comprising the action of drapering, outside a convex jig or inside a concave mold, forming a volume whose contour-envelope conforms to the shape exterior of the future carcass, a flexible cord of great length, made of fibers impregnated with synthetic resin intended to harden later, cord describing a suitable path with comings and goings and crossings such that the cage thus created constitutes a mesh network with many nodes or crosses, characterized in that

- at the location of each future node, has been placed in advance, and arranged in a removable manner, a threaded rod or

analogous substantially perpendicular to the plane tangent to the volume envelope of the template or mold, then

during the draping of the cord around the jig or in the mold, draping which consists in bringing into contact with the surface of the latter the flexible cord preferably stretched, while constantly making sure to maintain this contact,

is a future node bypassing the stem

corresponding, before continuing the routing of the cord to a neighboring rod, then

- the cord is brought back to a future node to

meet, by crossing it, the cord element which is present there, and the corresponding rod is bypassed again, with the cord element held at this moment, before to route it and move on to the next stem, node or future node, then

having thus proceeded with each rod, a nut with washer is placed on each of these threaded rods and it is tightened until a crushing of the knot is obtained, sufficient to ensure a self-welding of the cord elements between them, then

- After curing and self-welding of the bead elements together at all nodes, is removed at each node, the nut, the washer and the threaded rod itself, and it clears the carcass of the template or of the mold.

2) A method of constructing a lightweight carcass according to claim 1, said carcass being intended to be a movable or transportable element having the shape of a cage. 3) The method of claim 2 wherein the movable member is a vehicle carcass.

4) The method of claim 2 wherein the movable member is a wind turbine blade.

5) The method of claim 1 further characterized in that the cord consists of a single single rope, formed of an assembly of fibers contiguous parallel impregnation of synthetic resin.

6) Process according to claim 5 wherein the cord is twisted on itself, prior to its implementation. 7) A method according to claim 1, 5 or 6, the cord consisting of two strings instead of one, these two strings being associated by twisting along their entire length.

8) A method according to claim 1, 5 or 6, the cord consisting of three strings instead of one, these three ropes being associated by braiding along their entire length.

9) The method of claim 5 or 6, further characterized in that the circumvention of the threaded rod by the cord, is 1/5 to 15/5 of a turn, and preferably 1/4 to 5/4 of tower.

10) A method according to claim 7 or 8, further characterized in that the circumvention of the threaded rod by the bead results from a local adaptation of the natural curvature of the ropes that compose it, adaptation which is essentially an increase

caused curvature in places touching the threaded rod.

11) A method of construction according to claim 1, further characterized in that the circumvention of the threaded rod by the cord, is from one fifth to fifteen fifths of a turn, and preferably from one quarter to five quarters of a turn.

12) A construction method according to any one of the preceding claims, characterized in that the cord during draping from one node or future node to join another, not adjacent, but located far from the first, so this cord traverses the interior of the volume formed by the template or the mold, which in this case were eventually made to also provide support for the cord during its crossing, and in such a way that the together can be easily dismantled later.

13) Method according to any one of the preceding claims further characterized in that the impregnation resin of the cord has been added a chemical component with high adhesion power, likely to favor the adhesion of the resin with itself, even when it is already in the course of partial polymerization.

14) Method according to any one of the preceding claims further characterized in that the shape and the number of meshes of the cage are provided in such a way that the nodes, in particular the central hole, obtained by construction itself, are suitable for to cooperate with means for fixing the elements of the skin intended to surround the carcass.

15) carcass for mobile structure formed of a high strength fiber mesh mesh network impregnated with cured synthetic resin, network whose nodes comprise a crushed area.

16) Carcass according to claim 15 whose nodes further comprise a central hole.