WEDGE FILLER PREFORM

Abstract

A filler preform in a wedge form includes reinforcing fiber bundles consisting of reinforcing fiber filaments, wherein the filaments are directed parallel to each other within the fiber bundle, wherein the fiber bundle contains a first resin composition in a concentration in the range from 1 to 10 wt. % relative to the fiber weight, wherein the fiber bundles have a length in the range from 2 to 20 mm and at least 60% of the fiber bundles are reversibly fixed in a curved form within the wedge filler preform whereby flanks of the curved fiber bundles create an opening angle of less than 120° and the opening angle of the curved fiber bundles relates with an opening angle of the wedge form of the wedge filler preform. A method for producing the wedge filler preform and a method for producing a reinforcing fiber composite include a filler perform.

Claims

1. Wedge filler preform comprising reinforcing fiber bundles consisting of reinforcing fiber filaments, wherein the filaments are directed parallel to each other within the reinforcing fiber bundle, wherein the reinforcing fiber bundle contains a first resin composition in a concentration in the range from 1 to 10 wt. % relative to the fiber weight, wherein the reinforcing fiber bundles have a length in the range from 2 to 20 mm and at least 60% of the reinforcing fiber bundles are reversibly fixed in a curved form within the wedge filler preform, whereby further flanks of the curved reinforcing fiber bundles create an further opening angle of less than 120° and the further opening angle of the curved reinforcing fiber bundles is positioned in a similar direction and relates with an opening angle of the wedge filler preform.

2. Wedge filler preform according to claim 1, wherein the reinforcing fibers of the reinforcing fiber bundles are carbon fibers.

3. Wedge filler preform according to claim 1, wherein each reinforcing fiber bundle has 500 to 24,000 reinforcing fiber filaments.

4. Wedge filler preform, according to claim 1 wherein the reinforcing fiber bundles are homogeneously distributed over the wedge filler preform.

5. Wedge filler preform, according to claim 1, wherein the curved reinforcing fiber bundles are oriented anisotropically in the direction parallel of the opening angle of the wedge filler preform.

6. Wedge filler preform according to claim 1, wherein the width of the reinforcing fiber bundles varies in the range of 0.5 to 10 mm.

7. Wedge filler preform according to claim 1, wherein the total amount of resin within the entire wedge filler preform is less than 10 wt. % relative to the total fiber weight of the wedge filler preform.

8. Wedge filler preform according to claim 1, wherein the wedge filler preform has on at least one surface side a textile layer or the wedge filler preform is covered by at least one textile layer.

9. Wedge filler preform according to claim 1, wherein the wedge filler preform is partially or completely separated in parts and arranged on a flexible textile layer.

10. Wedge filler preform according to claim 9, wherein the flexible textile layer is a woven, non-woven or unidirectional fiber layer.

11. Wedge filler preform according to claim 1, wherein the wedge filler preform has a constant mass per unit area.

12. Fiber composite comprising a wedge filler preform according to claim 1, whereby the wedge filler preform fits variable cavities of the composite.

13. Method for producing a wedge filler preform according to claim 1, wherein reinforcing fiber bundles comprising a first resin composition in a concentration in the range from 1 to 10 wt. % relative to the fiber weight, are filled into a wedge formed mold, whereby the wedge formed mold comprises two flanks and in between an mold opening angle and two end faces, whereby each surface area of the flanks is larger than each surface area of the end faces, whereby the fiber filaments of the reinforcing fiber bundles are directed parallel to each other within each reinforcing fiber bundle, wherein a force and a thermal energy is applied to the reinforcing fiber bundles in the wedge formed mold, whereby the force acts only on at least one of the flanks of the wedged formed mold and due to the force at least 60% of the reinforcing fiber bundles is curved and further flanks of the reinforcing curved fiber bundles create an further opening angle of less than 120° and the further opening angle of the reinforcing curved fiber bundles is positioned in a similar direction and relates with an mold opening angle of the wedge formed mold, whereby the curved form of the reinforcing fiber bundles is reversibly fixed due to partial melting of the first resin composition by the thermal energy.

14. Method for producing a reinforced fiber composite, whereby a wedge filler preform manufactured according to claim 13 is used, whereby the wedge filler preform is arranged inside of a further fiber preform, whereby both preforms are located into a further mold and a second resin composition is applied into the further mold, whereby the opening angles of at least 20% of the curved reinforcing fiber bundles increase by at least 5° and fixed in this position after applying the second resin composition.

15. Method for producing a reinforcing fiber composite according to claim 14, whereby the wedge filler preform has a constant thickness gradient and the further fiber preform has cavities with thickness variations.

Description

[0038] FIG. 1 shows schematically a method for producing a wedge filler preform.

[0039] FIG. 3 shows schematically a form of a reinforcing composite.

[0040] FIG. 4 shows a wedge filler preform.

[0041] FIG. 5 shows schematically two embodiments for a wedge filer preform.

[0042] FIG. 6 shows schematically a wedge filler preform in a curved form.

[0043] In FIG. 1 a method for producing the wedge filler preform 1 (not shown) is schematically shown. In step A the reinforcing fiber bundles 2 are sprayed into a wedged formed mold 3. The fiber bundles 2 are distributed homogenously into the wedged formed mold 3. In this processing step nearly nil curved fiber bundles 2′(not shown) are presented within the wedged formed mold 3.

[0044] In a process step B the wedged formed mold 1 is closed and a thermal energy 4 is applied to the wedged formed mold 3 and thus to the distributed fiber bundles 2. Due to the thermal energy 4 the first resin composition of the fiber bundles 2 melts at least partially and gets a tacky character.

[0045] In a process step C a force 5 is applied to the wedged formed mold 3 and thus to the fiber bundles 2. The force 5 acts on a flank 8 of the wedged formed mold 3 and inside the wedged formed mold 3 the fiber bundles 2 are pressed in a curved form. Due to the at least partially melted first resin composition the curved form of the fiber bundles 2 are reversibly fixed within the wedged formed mold 3 (and thus within the wedge filler preform). Curved reinforcing fiber bundles are created. No further resin composition is used in this example for producing the wedge filler preform 1. The force 5 can also act on the fiber bundles 2 via both flanks 8 and 9 simultaneously.

[0046] In FIG. 2 a wedge filler preform 1 in a side view is shown. In the side view it can be seen that the wedge filler preform 1 has a vertex 7, two flanks 8′, 9′ and an opening angle α. Within the wedge filler preform 1 the fiber bundles are arranged and reversibly fixed in a curved form (curved fiber bundles 2′). The curved fiber bundles 2′ have a vertex, a first and second flank 8″, 9″ and an opening angle α′. The vertex of the curved fiber bundle 2′ is parallel to the vertex 7 of the wedge filler preform 1. Also the opening angle α of the wedge filler preform 1 is open to the same direction as the opening angle α′ of the curved fiber bundles 2′.

[0047] In the embodiment of FIG. 2 the wedge filler preform 1 has a textile layer, for example a fiber layer 13, as a sheath on the outer side of the wedge filler preform 1. Due to the fiber layer 13 the handling of the wedge filler preform 1 is easier.

[0048] In FIG. 3 an example for a form of a reinforcing fiber composite is shown. The form shows a cavity 12 with different thickness variations. A thickness variation is refillable with the wedge filler preform 1 without changing the mass per unit of the wedge filler preform 1. A cavity part 14 is empty afterwards the wedge filler preform 1 is filled within the cavity 12. After the composite is heated also cavity part 14 is filled with the wedge filler preform material.

[0049] In FIG. 4 a wedge filler preform 1 is shown. On the top side 15 of the wedge filler preform 1 the reinforcing fiber bundles 2 are oriented in a random (istropically) fashion, whereby the bundle form (filaments are parallel to each other within the bundle) is still existing in the wedge filler preform 1.

[0050] In FIG. 5 two embodiments for a wedged formed mold 3 and an obtained wedge filler preform 1 are shown. On top of the FIG. 5 a wedged formed mold 3 is shown with a triangular end face 11 and an opening angle β. The opening angle corresponds to the opening angle α of the wedged filler preform 1. This means the value of the opening angle α is approximately equal to the value of the opening angle β. In addition, the direction of the opening angle α is approximately equal the opening direction of the opening angle β. On the bottom of FIG. 5 a wedged formed mold 3 with a trapeze end face 11 is shown. The opening angle β is created by an imaginary extension of the flanks 8 and 9 of the wedged formed mold 3. Also, the wedge filler preform 1 obtained by this wedged formed mold 3 comprises a triangular end face.

[0051] In FIG. 6 a wedge filler preform 1—has an additional a flexible textile layer 13 (for example an non-crimp fabric)—on the backside of the wedge filler preform 1. The wedge filler preform 1 can be partially or completely separated into parts, whereby the flexible textile layer 13 holds the parts together (for example via gluing the parts on the flexible textile layer 13). Thus, the flexible textile layer 13 is not separated. Due to the separation the wedge filler preform 1 is adaptable on curved further preforms.