DE102007003274B3 - Method e.g. for reinforcing foam material, involves providing processing area and creating processing area with laminar for partial surrounding gap and fiber-surface material is arranged into gap and has foam material - Google Patents

Abstract

The method involves providing a processing area (200) and creating a processing area (200) with a laminar for a partial surrounding gap. A fiber-surface material (202) is arranged into the gap and has a foam material (106). A rod (104) is introduced into the foam material (106) and which is entered through the surface (210) of the foam material to the fiber surface material (202). The fiber surface material (202) infiltrates with a matrix system. An independent claim is included for a use of the method, a composite core construction component, and an aircraft.

Description

The The present invention relates to the technical field of composites. In particular, the invention relates to a method for reinforcing a Foam material. Furthermore The invention relates to a core composite component comprising a reinforced foam material and an aircraft having such a core composite component or with a structural component produced using the method according to the invention reinforced has been.

Even though on any reinforced Foam materials are applicable, the present invention as well its underlying problem in terms of area-like Core composites with an enclosed between outer layers, through foam reinforced with a resin infiltrated foam core explained in more detail.

Composites and in particular so-called core networks find due to their good relationship stiffness and strength to density in the field of aircraft construction a wide range of applications. Core composites generally point an upper and a lower cover layer, between which to increase the stiffness, for example, a vertically extending cells with hexagonal cross-section running core structure is located.

A Alternative to such honeycomb structures provide rigid foams They show, among other things, in the field of thermal and acoustic insulation as well as in the process technology for the production of core composites advantages across from Honeycomb structures on. A disadvantage of these foam structures is in the lower mechanical strength at the same density.

Around To compensate for this lower strength, core composites with foam cores can reinforced by introducing braces into the core. In particular sewing method provide the opportunity Fibers and threads for Formation of struts at different angles and with over the To introduce component of varying density. Due to the technically achievable Stitch speeds is a speedy reinforcement of the component possible. After a Harzinfiltrationsprozess carry the pierced areas for mechanical reinforcement of the basic foam material. Such structures are used already in core composite structures in truck and shipbuilding.

The DE 10 2005 024 408 A1 discloses a sewing method in which the first step is to pierce a through-hole in the foam material with the needle from one side, in order then to pick up a fiber bundle provided on the other side with the needle and to be able to draw it into the foam material. Since the fiber bundle largely fills the through-hole, only little resin is incorporated in a subsequent infiltration, which leads to an improved ratio of the achieved mechanical strength to the density of the core composite and makes suitable structures suitable for use in aircraft construction.

The GB 2 131 741 A discloses a method of repairing a damaged core composite component according to which the damaged area is cut out. Grooves are formed on a repair element and on the edge of the core composite component surrounding the cut-out region. After the repair element is inserted into the cut-out area, a curable filler mass is filled in the grooves.

The reinforcing However, the effect of bracing is based on a tensile / compressive load the introduced struts. These can only absorb forces when at both ends to a pressure-resistant element, as a rule a cover layer of the core composite are connected. Become centered severed or detached at one end, they are mechanically ineffective.

There the struts are typically at different defined angles go to the top layer, there is the problem that at a localized processing of such a reinforced core structure on a Machining point the mechanical strength of the core composite in one over the machined area beyond enlarged area, in the pursuit lose its mechanical effect. In this enlarged area becomes the unreinforced Foam material to the strength-determining element, which is above all for lightweight foam materials to a strong local change the mechanical properties leads.

It It is therefore an object of the present invention to provide a reinforcing method to create reinforced foam materials locally to work without it affecting the mechanical properties in an enlarged area comes to the processing point.

According to the invention this Task by a method for reinforcing a foam material with the features of claim 1 and by a core composite component solved with the features of claim 13.

The idea on which the present invention is based is that first of all a machining area is specified within which, at a later point in time, a localized machining of the foam material to be reinforced to be carried out.

Subsequently, will in the foam material, the given processing area areally at least partially enclosing Gap generated, d. H. a thinner, areal extended cavity, which is located in the foam material along the boundary surfaces of the Processing area extends. In this gap is a fiber surface material embedded so that the fiber material embedded in the foam material the outer boundary of the Processing area forms. In a further step, a Strut inserted into the foam material, which is attached to an outside the processing area located point of a surface of the foam material, the following entry surface is to be called, enters the foam material and from there to at least the fiber surface material extends. The fiber surface material is infiltrated with a matrix system.

in the Result connect the two ends of the embedded strut an outer surface of the foam material, the entrance surface, and the fibrous sheet material at the boundary surface the processing area inside the foam material. The strut is thus connected / bound at both ends, none of the both connection points lie within the processing area and the strut on the link between these two Connection points at no point the editing area happened. Will be done later Time localized to the interior of the editing area Processing of the reinforced Foam, remains the two-sided connection of the strut and thus their reinforcing Effect exist. Consequently, the inventive reinforcement allows a Foam material a subsequent localized processing within the specified editing area, without it in one in one over the processing area extended area to an impairment the mechanical properties of the reinforced foam material comes.

The In another aspect, the invention provides a core composite component a core having a foam material and a foam material arranged fibrous material, the one processing area of the core composite part at least partially areal limited. At least one strut is embedded in the foam material and extends from an entrance surface of the foam material from outside the machining area to at least the fiber surface material. This composite core component has the advantage that it is within the Editable local area is editable without the mechanical properties of the core composite component outside of the editing area become.

In the dependent claims find advantageous embodiments and improvements of Invention.

According to one preferred development is further provided with the Fiber surface material infiltrated gap with the matrix system to fill. This is particularly advantageous as a mechanically particularly stable limitation of the machining area arises, so that the editing area under the localized Processing z. B. completely can be gutted without the fiber material from the surrounding foam material solves. there it comes to the integration of the strut in the resin matrix of the fibrous sheet material, so that the strut in a simple way reliable on the boundary surface of the Machining area is anchored.

According to one preferred development comprises generating the gap more Partial steps. First is removed within the working area of the foam material, z. B. by drilling or milling of the area. Furthermore, an embedding part is provided, which is shaped according to the processing area such that it substantially fills it while leaving the gap. The Embedding part is therefore similar shaped but a little smaller than the machining area, taking the difference corresponds to the intended gap. By finally inserting the Embedding part in the processing area results in the desired gap.

These Training is particularly advantageous because of the machining area can be defined with simple tools like a drill. Farther can the material for the embedment part in for the intended localized Bearbei tion expedient manner deviating from the material of the foam surrounding the processing area chosen become.

According to one preferred development includes the storage of the fibrous sheet material the Covering an outer surface of the Embedding part with the fibrous material, before inserting the embedding part. This is advantageous because the soft fiber material is particularly light around the embedding part can be draped if it is still outside the edit area. According to one alternative training is before the insertion of the embedding part an inner surface the processing area covered with the fiber surface material, for. B. if depending on the shape of the editing area this approach is easier. Both developments can also be combined.

According to one preferred development, the strut is introduced by first in the foam material a hole is created extending from a point on the entrance surface of the Foam material, outside the machining area, to at least the fibrous material extends. Subsequently will at least be a fiber bundle pulled into the hole. This has the advantage of being so special light strut form. Preferably, furthermore, a step of filling the with the at least a fiber bundle interspersed holes with a matrix system provided what the strut further strengthened and improved their connectivity to the endpoints. This filling can z. B. take place together with the infiltration of the fiber surface material.

Preferably The hole is created by a needle through the foam material and the fibrous sheet material to an exit surface of the Foam material is stung. This has the advantage that the Strut can be formed in the same way as other struts in the foam material outside of the editing area. Thus, regardless of the presence or the location of the machining area of the entire foam material be provided with methods of the prior art quickly with struts.

According to one preferred development is still after the introduction of the Strive for a step of at least partially removing the foam material including the strut provided within the processing area. To this Way, the processing area z. B. as a feedthrough hole for cables serve. Preferably, an insert is in the processing area used, which take over other functions such as a fastener can. Preferably the diameter of the insert at least 2/3 of the diameter of the editing area and at most less than the diameter of the machining area. In this Area remains a space of appropriate size, the stable integration of the insert with a filler such as B. expansion adhesive can be filled.

According to one preferred development will continue before removing the foam material including the strut has at least one cover layer on at least one surface of the foam material formed or arranged in the above the processing area a cover layer opening is generated, for. B. by drilling. Preferably, the diameter is this cover layer opening at least 2/3 of the diameter of the machining area and at most less than a diameter of the machining area. In this way an insert can be fitted accurately in the cover layer opening, while the underlying processing area for connection of the insert part with a filling material filled can be.

According to one preferred embodiment of the core composite component according to the invention the processing area filled with the foam material. There the properties of such a core composite component in the processing area hardly differ from the properties outside the editing area, can z. B. processing areas of this kind as a precaution in a core composite component be, so to a later Time to be decided after installation of the core composite part can, if the editing area should actually be edited.

According to one preferred development, is at least one surface of the Foam core material formed by a cover layer, in particular the processing area completely covered. In this way, the processing area is above the top layer invisible, so that such processing areas in a core composite part without impairment the external appearance of the Core composite z. B. in a wall covering for possible later processing be prepared.

According to one preferred development is in the cover layer within the processing area a Topsheet opening formed, in particular, the diameter of the cover layer opening at least 2/3 of the diameter of the machining area and at most less than a diameter of the machining area. Preferably is within the processing area an insert in the foam material used, in particular a diameter of the insert part is approximately equal to the diameter of the cover layer opening. In this way the insert is held in the cover layer opening. The insert part can fulfill any functions. According to one Further, it includes a fastener for attachment the core composite component with any other components, eg. B. a nut.

Preferably the machining area is essential with a filler material filled, in which the insert is integrated, in particular the insert has a lateral depression profile that at least partially through the filler material filled out is. this leads to to a particularly secure anchoring as well as to a weight saving. The filler material preferably comprises an adhesive, in particular an expansion adhesive the glue the insert and the fibrous material together are.

The Invention will be described below with reference to exemplary embodiments with reference explained in more detail on the accompanying figures of the drawing.

From show the figures:

1 a schematic sectional view of an exemplary core composite with a reinforced foam core; and

2A D is an illustration in schematic cross-sectional views of the reinforcement and localized machining of a foam material according to one embodiment of the present invention.

In In the figures, the same reference numerals designate the same or the same function Components, unless stated otherwise.

1 shows a fragmentary schematic sectional view of an example of a core composite component 100 one between two cover layers 108 . 108 ' enclosed core structure 102 having. The core structure 102 consists essentially of a foam material 106 , z. As a high-quality PMI rigid foam, as it proves to be advantageous in aviation. Of course, however, other foams may be used, which consist for example of polytetrafluoroethylene or polyurethanes.

The one in the core structure 102 used foam material 106 is through a variety of aspirations 104 reinforced, between the two cover layers 108 . 108 ' through the foam material 106 and of which here is a single strut 104 is shown by way of example.

To form the strut 104 is in the foam material core 102 by means of a sewing method, a through hole has been introduced into which a fiber bundle 110 was stored. Subsequently, the through hole was infiltrated with resin (not shown).

The strut 104 is at both ends 112 . 114 on each one of the cover layers 108 . 108 ' created and attached, z. As part of an infiltration with resin. By way of example, one of the ends shows 112 in that the fiber bundle is between cover layer 108 ' and foam material can be embedded while the other end 114 shows that the fiber bundle 110 on the outside of a cover layer 108 can be created. Other mounting options are possible.

The strut 104 exemplifies an angle α with the cover layers 108 . 108 ' , By attaching both ends 112 . 114 the strut 104 is with appropriate bending of the core composite 100 the strut 104 loaded on train. A variety. similar struts, which are each loaded at different load of the core composite to train, can be introduced into the foam material under any angular position.

2A D shows in schematic cross-sectional views the reinforcement and further processing of a foam material 106 according to an embodiment of the present invention.

The in 2A in the initial state shown foam material 106 is one of two surfaces 210 . 212 limited, areally expanded semi-finished product of thickness s, of which the cross-sectional view of a section can be seen here. In a first processing step is, symbolized by the arrow 204 by drilling or milling the foam material within a machining area indicated by dashed lines 200 the foam material 106 away. In the embodiment shown, this processing area has the shape of a cylinder with diameter d1 and height s. Both the foam material 106 as well as the editing area 200 but can be of any other shape and size.

2 B shows the foam material 106 with the by the drilling process 204 hollowed out cylindrical processing area 200 , Additionally provided is an embedding part 208 , which is also made of a foam material and has the shape of a cylinder with height s and a diameter which is smaller by a small difference than the diameter d1 of the machining area 200 is. The foam material of the embedding part can be deviating or the same kind as the foam material surrounding the processing area 106 be. The embedment part 208 is with a fiber surface material 202 whose thickness is about half the difference between the diameter of the embedding part and the diameter d1 of the machining area, so that the diameter of the embedding part 208 including the sheathing 202 made of fibrous material 202 approximately equal to the diameter of the machining area 200 is. The embedment part 208 will now be in the editing area 200 inserted precisely so that the fiber material in a gap between the embedding part 208 and the surrounding foam material 106 to come to rest.

Subsequently, with methods of the prior art such. B. the basis of 1 explained a gain of the foam material 106 including by the embedding part 208 filled machining area, the result in 2C shown. A series of embedded struts 104 pull through at different angles the foam material 106 including the inserted embedding part 208 and his sheath 202 , This is z. B. by applying the basis of 1 to achieve the described method, since both the foam material 106 inside and outside the editing area 200 as well as the fiber material 202 can be pierced by needles. As for the procedure of 1 already mentioned, arise through holes with embedded fiber bundles, which are then infiltrated with a resin, eg. By pressing resin from one side of the foam material into the through-holes. In the case of the method shown here, the fiber surface material is simultaneously with the fiber bundles 202 infiltrated, so that such aspiration 104 passing through the fiber surface material 202 pass through, experienced at the point of passage a firm connection through the resin.

On the surfaces 210 . 212 then cover layers 216 . 216 ' arranged, for example, also from a fiber surface material such. As a paper may be, which is then impregnated with resin. Here are the struts 104 firmly to the cover layers 216 . 216 ' tethered. In the core composite thus produced 100 Condition is the editing area 200 not visible from the outside.

As by the arrow symbol 206 in 2C is now indicated by drilling within the editing area 200 a cylindrical decorating area 224 eroded, with cover layers 216 . 216 ' , Foam material of the embedding part 208 and striving 104 be removed equally. This will be within the editing area 200 Remaining remains of struts mechanically ineffective, the outboard sections of the same struts 104 remain due to their attachment to the fiber surface material 202 effective. The diameter d2 of the core area 224 is about 2/3 of the diameter d1 of the machining area.

As a result in 2D to see, now within the processing area still remaining foam material of the embedding part 208 and the remnants of the remaining within the editing area 200 extending sections of the struts 104 removed, z. B. by milling the processing area through the top layer opening. This creates an undercut.

Subsequently, an insert part 214 with an outer diameter d2, the diameter of the by drilling 206 formed cover layer opening, in the processing area 200 used. In a final step becomes an adhesive 222 , z. As an expansion adhesive, in the processing area 200 injected when curing the insert 214 firmly attached to the core network 100 binds. By the undercut of the cover layer opening as well as by a on the insert part 214 trained depth profile 220 is the insert and the z. B. trained fastener 218 by the cured adhesive also positively held in position.

Even though the present invention with reference to preferred embodiments has been described herein, it is not limited thereto, but on diverse Modifiable way.

For example can be integrated into the processing area insert for fulfillment any functions as implementation, Sensor, switches, etc. may be formed. The editing area as well as the core composite can be of any geometric Be shape. The editing area can, for. B. when installing a sensor the top layer completely be closed. Instead of the described struts of impregnated fiber bundles pultruded Plastic rods used become.

100

sandwich

102

core

104

strut

106

Foam material

108 108 '

topcoat

110

fiber bundles

112 114

end up the strut

200

editing area

202

Fiber surface material

204

Drill of the editing area

206

Drill the cover layer opening

208

embedding part

210

entering surface

212

exit surface

214

insert

216 216 '

topsheet

218

fastener

220

depth profile

222

filling material

224

Entkernbereich

d1

diameter of the editing area

d2

diameter the cover layer opening

Claims (26)

Method for reinforcing a foam material ( 106 ) with the following method steps: specifying a processing area ( 200 ); Creating a processing area ( 200 ) areal at least partially enclosing gap; Storing a fibrous material ( 202 ) in the Gap in the foam material ( 106 ); Inserting a strut ( 104 ) in the foam material ( 106 ) extending from an entrance surface ( 210 ) of the foam material ( 106 ) from outside the editing area ( 200 ) to at least the fibrous material ( 202 ) extends; and infiltrating the fibrous sheet material ( 202 ) with a matrix system. A method according to claim 1, characterized in that the with the fiber surface material ( 202 ) is filled with filled gap with the matrix system. Method according to claim 1 or 2, characterized in that the generation of the gap comprises the following sub-steps: removal ( 204 ) of the foam material ( 106 ) in the editing area ( 200 ); Provision of an embedding part ( 208 ), which corresponds to the processing area ( 200 ) is shaped so that it substantially fills it while leaving the gap; and inserting the embedding part ( 208 ) into the processing area ( 200 ). Method according to claim 3, characterized in that the storage of the fibrous surface material ( 202 ) the covering of an outer surface of the embedding part ( 208 ) with the fiber surface material ( 202 ) before inserting the embedding part ( 208 ). A method according to claim 3 or 4, characterized in that the incorporation of the fibrous material ( 202 ) covering an inner surface of the processing area ( 200 ) with the fiber surface material ( 202 ) before inserting the embedding part ( 208 ). Method according to at least one of the preceding claims, characterized in that the introduction of the strut ( 104 ) comprises the following substeps: producing a hole in the foam material ( 106 ) extending from the entrance surface ( 210 ) of the foam material ( 106 ) outside the editing area ( 200 ) to at least the fibrous material ( 202 ) extends; and retraction of at least one fiber bundle ( 110 ) in the hole. A method according to claim 6, characterized in that further comprises a step of filling the with the at least one fiber bundle ( 110 ) interspersed hole is provided with the matrix system. A method according to claim 6 or 7, characterized in that the production of the hole by piercing a needle through the foam material ( 106 ) and the fibrous material ( 202 ) to an exit surface ( 212 ) of the foam material ( 106 ) he follows. Method according to at least one of the preceding claims, characterized in that furthermore after the introduction of the strut ( 104 ) a step of at least partially removing the foam material ( 106 ) including the strut ( 104 ) within the editing area ( 200 ) is provided. A method according to claim 9, characterized in that further comprises a step of inserting an insert ( 214 ) is provided in the processing area, wherein in particular the diameter of the insert part ( 214 ) at least 2/3 of the diameter of the machining area ( 200 ) and at most less than the diameter of the processing area ( 200 ) is. A method according to claim 10, characterized in that further before the step of removing the foam material ( 106 ) including the strut ( 104 ) the steps are provided: forming or arranging at least one cover layer ( 216 . 216 ' ) on at least one surface ( 210 . 212 ) of the foam material; and generating ( 206 ) a cover layer opening in the at least one cover layer ( 216 . 216 ' ) above the processing area ( 200 ); wherein, in particular, the diameter of the cover layer opening is at least 2/3 of the diameter (d2) of the machining area ( 200 ) and at most less than a diameter (d1) of the machining area ( 200 ) is. Use of the method according to at least one of claims 1 to 11 for inserting a fastening element ( 214 ) into a core network ( 100 ). Core composite component ( 100 ), comprising: a core ( 102 ), which is a foam material ( 106 ) having; a in the foam material ( 106 ) arranged fiber surface material ( 202 ), which has a processing area ( 200 ) of the core composite part bounded at least partially areally; and at least one strut ( 104 ) embedded in the foam material ( 106 ) and from an entrance surface ( 210 ) of the foam material ( 106 ) from outside the editing area ( 200 ) to at least the fibrous material ( 202 ). Core composite component according to claim 13, since characterized in that the fibrous sheet material ( 202 ) is infiltrated with a resin, wherein in particular the at least one strut is incorporated in the resin. Core composite component according to claim 13 or 14, characterized in that the at least one strut ( 104 ) at least one arranged in a through hole fiber bundle ( 110 ) infiltrated, in particular, with a resin. Core composite component according to at least one of claims 13 to 15, characterized in that the processing region ( 200 ) with the foam material ( 106 ) is filled. Core composite component according to at least one of claims 13 to 16, characterized in that the at least one strut is further defined by the sheet material ( 202 ) to an exit surface ( 212 ) of the foam material. Core composite component according to at least one of claims 13 to 17, characterized in that at least one surface ( 210 . 212 ) of the foam core ( 206 ) through a cover layer ( 216 . 216 ' ) is trained. Core composite component according to claim 18, characterized in that the cover layer ( 216 . 216 ' ) completely covers the processing area. Core composite component according to claim 18, characterized in that in the cover layer ( 216 . 216 ' ) within the editing area ( 200 ) a cover layer opening is formed; wherein, in particular, the diameter of the cover layer opening is at least 2/3 of the diameter (d2) of the machining area ( 200 ) and at most less than a diameter (d1) of the machining area ( 200 ) is. Core composite component according to claim 20, characterized in that within the processing area an insert part ( 214 ) in the foam material ( 106 ) is used, wherein in particular a diameter of the insert part ( 214 ) is approximately equal to the diameter (d1) of the cover layer opening. Core composite component according to claim 21, characterized in that the insert part ( 214 ) a fastener ( 218 ) for fastening the core composite component ( 100 ) with other components. Core composite component according to claim 21 or 22, characterized in that the processing area substantially with a filling material ( 222 ), in which the insert part ( 214 ) is involved. Core composite component according to claim 23, characterized in that the insert part ( 214 ) a lateral deepening profile ( 220 ), which at least partially by the filling material ( 222 ) is filled out. Core composite component according to claim 23 or 24, characterized in that the filler material ( 222 ) has an adhesive, in particular an expansion adhesive, and the insert part ( 214 ) and the fibrous material ( 202 ) through the filler material ( 222 ) are glued together. Aircraft with a composite core component ( 100 ) according to at least one of claims 13 to 25 or with a structural component ( 100 ) prepared using the method of any one of claims 1 to 11.