DE102015204371A1 - Process for producing a fiber composite component - Google Patents

Abstract

The invention relates to a method for producing a fiber composite component (10) containing recycled carbon fibers (2), in particular a fiber composite component (10) for a motor vehicle, comprising the steps: - Providing sheet-like semi-finished fiber products (3) containing recycled carbon fibers (2), wherein a proportion of recycled carbon fibers (2) is at least 50% by volume, based on the total volume of fibers used in the semi-finished fiber product (3), - producing a fiber composite standard component with a defined number of semifinished fiber products (3), defined fiber material, defined matrix material and Defined layer arrangement, - Determining the bending stiffness of the fiber composite component (10) according to the following formula (1): where Bbv (t) is the bending stiffness of the fiber composite component (10), Ebv the elastic modulus of the fiber composite component (10), tsoll the layer thickness of the fiber composite component (10 ) and ν is the transverse contraction number, with Ebv using ref where E1 is the modulus of elasticity of the fiber composite standard component, φlit the fiber volume content of the fiber composite standard component and φ (t) is the fiber volume content in the fiber composite component (10), - arranging a number of flat semi-finished fiber products (3) the desired bending stiffness Bbv (t) is obtained, - impregnating the flat semi-finished fiber products (3) with matrix material (9) and - hardening the matrix material (9).

Description

The present invention relates to a method for the production of fiber composite components from recycled carbon fiber material and to a use of the method according to the invention.

Fiber composite components are known in different embodiments from the prior art. In particular, in the automotive industry emphasis is placed on lightweight fiber composite components. So describes DE 10 2005 026 889 A1 Door trim for motor vehicles with a center module made of a fiberglass-polyurethane fiber composite material, the z. B. can be produced by an injection molding process. In the light of resource conservation, waste volume reduction and cost savings, the demand for recycled and / or recyclable fiber composite components with a simultaneous focus on weight-reducing materials is currently becoming the focus of the manufacturing industry. These requirements can not be met with previous fiber composite materials.

Based on this prior art, it is therefore an object of the present invention to provide a method for producing fiber composite components, the resource savings, reduces disposal costs, contributes to waste prevention and at the same time is easy to apply without high technical complexity and thus cost-effective production of fiber composite components in leichtbauender Construction allows.

The object is achieved by a method in which recycled carbon fiber-containing sheet semi-finished fiber products are specifically implemented. Flat semi-finished fiber products, which are used here, are z. As fiber mats, fiber fabric, nonwoven fabrics, fiber webs and the like, and thus such structures, which usually have in one dimension, the thickness direction, or the wall thickness or layer thickness, a small extent. The flat semi-finished fiber products contain recycled carbon fibers, wherein a proportion of recycled carbon fibers at least 50 vol .-%, in particular 100 vol .-%, based on the total volume of the fibers used in the semifinished fiber, is. Such semi-finished fiber products are unbinding, so resin-free, and can be produced by any method, wherein an exemplary manufacturing process i) providing dry fiber waste, such as Verschnittresten, z. B. Gelegeabfall, production residues, Preformverschnitten and the like, ii) preparation of the fibers under exposure and separation of the fibers by z. B. punching or cutting the fiber waste and opening it, substantially without damaging the fibers, and iii) the production of a flat semi-finished fiber, provides. Further or additional process steps may be provided.

wobei B_bv(t) die Biegesteifigkeit des herzustellenden Faserverbundbauteils, E_bv das Elastizitätsmodul des Faserverbundbauteils, t_soll die Schichtdicke des Faserverbundbauteils und ν die Querkontraktionszahl ist. ν, die Querkontraktionszahl oder Poissonzahl, ist eine dimensionslose Materialkonstante. Sie gibt das Verhältnis der relativen Querdehnung zu einer relativen Längsdehnung an:

Usually, high mechanical requirements are placed on a fiber composite component. Thus, fiber composite components must have a certain flexural rigidity in order to find application as support structure or stiffening structure. In order to take into account the requirements of a low dead weight according to the invention, the expected bending stiffness of the fiber composite component to be produced is determined in order to then determine a minimum number of flat semifinished fiber or a given wall stiffness a minimum wall thickness of the fiber composite component. The flexural rigidity of the fiber composite component to be produced is determined in accordance with the following formula (1)

where B _bv (t) is the bending stiffness of the fiber composite component to be produced, E _{bv is} the modulus of elasticity of the fiber composite component, t _is the layer thickness of the fiber composite component and ν is the transverse contraction number. ν, the transverse contraction number or Poisson number, is a dimensionless material constant. It gives the ratio of the relative transverse strain to a relative longitudinal strain:

Ie. it indicates how the cross section changes as the length changes. In the case of fiber composite components, the following generally applies in the literature: ν = 0.35. The value can also be determined analogously via the mixing rule.

In order to be able to determine the modulus of elasticity of the fiber composite component E _bv , according to the invention a fiber composite standard component with a defined number of semifinished fiber products, defined fiber material (quantity and chemical nature of the fiber material), defined matrix material (quantity and chemical nature of the matrix material) and defined layer arrangement (stratification of the Semi-finished fiber products). The fiber composite standard component serves for parameter determination for the fiber composite component actually to be produced and has the same physical and chemical nature (matrix material, fiber material, layer arrangement, etc.) as the fiber composite component to be produced. Thus, the elastic modulus E _{bv of} the fiber composite component to be produced can be determined by the following formula (2):

In this case, E _{lit is} the modulus of elasticity of the fiber composite standard component, φ _{lit is} the fiber volume content of the fiber composite standard component and φ (t) is the fiber volume content in the fiber composite component. The elastic modulus E _{lit of} the fiber composite standard component can be determined by non-destructive, experimental tests or by mathematical calculation.

As a result, the bending stiffness determined for the fiber composite component to be produced can be set in relation to a desired bending stiffness. If, for example, an existing fiber composite component with a certain bending stiffness is replaced by the fiber composite component produced according to the invention with at least 50% by volume fraction of recycled carbon fibers, the flexural strength B _bv (t) determined for the fiber composite component produced according to the invention gives a good indication the estimation of the mechanical equivalence of the fiber composite components. Only by correlating the flexural stiffness of the fiber composite component containing recycled carbon fibers with the desired overall bending stiffness to be achieved can a fiber composite component with outstanding mechanical and therefore high quality properties be produced, due to the low inherent weight of carbon fibers over conventional glass fibers, with minimal inherent weight.

Taking into account the wall thickness t _soll (this corresponds to the layer thickness of the fiber composite component), the number of fiber semifinished products to be used for the fiber composite component can be determined from the determined bending stiffness of the fiber composite component to be produced. Alternatively, a minimum wall thickness of the fiber composite component to be produced for a given number of flat fiber semi-finished products can be determined via the bending stiffness of the reference fiber composite component.

Once the number of planar semifinished fiber semi-finished products required to obtain the desired bending stiffness has been determined or determined, the flat semi-finished fiber products are arranged, for example stacked, and impregnated with matrix material. After curing of the matrix material, a highly rigid, weight-reduced fiber composite component is obtained which, due to the use of recycled carbon fiber materials, saves resources, reduces disposal costs and contributes to waste prevention. The method can be implemented inexpensively without high technical complexity and, due to the determination of the minimum required number of semifinished fiber products to be used, it is possible to produce fiber composite components with very small wall thickness without sacrificing stability. As a result, the inventive method is particularly suitable for producing a fiber composite component for a motor vehicle.

The dependent claims contain advantageous developments and refinements of the invention.

Due to the good processability and cost-effective production, flat semi-finished fiber products in the form of fiber webs are particularly well suited. Particularly advantageous are all used, so arranged semi-finished fiber webs.

Further advantageously, the nonwoven fabrics have an isotropic or anisotropic fiber orientation. An anisotropic fiber direction can be obtained, for example, by a carding process in which the prepared fibers are aligned after opening the fiber waste materials by, for example, combing. The use of anisotropically oriented semifinished fiber products has proven to be advantageous, in particular in the event of any likewise anisotropic load effects.

A further weight reduction with simultaneous cost reduction can advantageously be achieved by the fact that the flat semi-finished fiber products contain recycled carbon fibers as the only fiber material.

wobei n_bv die Anzahl der anzuordnenden flächigen Faserhalbzeuge, t_soll die Wandstärke des Faserverbundbauteils, φ(t) der Faservolumengehalt im Faserverbundbauteil, ρ_φ die Dichte der Fasern im Faserverbundbauteil und Y_bv das Flächengewicht des Faserhalbzeugs ist, wobei φ(t) durch nachfolgende Formel (4) bestimmt wird:

The method according to the invention provides particularly advantageously that, depending on the desired bending stiffness B _bv (t) of the fiber composite component, a minimum number of planar semi-finished fiber products to be stacked is determined by means of the following formula:

where n _{bv is} the number of planar semifinished fiber products to be arranged, t _is the wall thickness of the fiber composite component, φ (t) is the fiber volume content in the fiber composite component, ρ _{φ is} the density of the fibers in the fiber composite component and Y _{bv is} the weight per unit area of the semifinished fiber product, where φ (t) is given by Formula (4) is determined:

Again, n _{bv is} the number of semi-finished fiber products to be arranged, Y _{bv is} the basis weight of a semifinished fiber and ρ _{cf is} the density of the fiber material in the semifinished fiber product. If different fiber materials are used, the density of the fiber material can be determined by the rule of mixtures. Thus, it is possible, with the same flexural rigidity, to use the smallest possible number of semifinished fiber products, which is advantageous not only in terms of material costs and production costs of the fiber composite component, but also with regard to a resource-conserving fiber composite component production.

wobei φ(t) wiederum durch nachfolgende Formel (4) bestimmt wird:

wobei n_bv die Anzahl der anzuordnenden Faserhalbzeuge, Y_bv das Flächengewicht eines Faserhalbzeugs (3) und ρ_cf die Dichte des Fasermaterials im Faserhalbzeug ist.With a given flexural stiffness E _bv (t) of the fiber composite _{component to} be produced, the method according to the invention also provides a step of determining a minimum wall thickness of the fiber composite component using the following formula (5):

where φ (t) is again determined by the following formula (4):

wherein n _bv the number of to be arranged semi-finished fiber, Y _bv is the basis weight of a fibrous semifinished product (3) and ρ _cf the density of the fiber material in the fiber semi-finished product.

From formula (3) or formula (5) it follows that two parameters are variable: the number of semi-finished fiber products n _bv in the fiber composite component to be produced and the wall thickness t _{soll of} the fiber composite component. Thus, either with a given wall thickness, the minimum necessary number of semi-finished fiber can be determined to obtain a predetermined desired bending stiffness, or it can be determined at a given number of semi-finished fiber products the minimum possible wall thickness to obtain a predetermined desired bending stiffness.

If the minimum possible wall thickness is determined, then this is a decisive factor for reducing the weight of the fiber composite component, which also has an effect on the cost of the fiber composite component.

The stability of the fiber composite component to be produced can advantageously be improved by introducing at least one reinforcing element onto and / or between the planar semi-finished fiber products to be arranged. Particularly suitable for this purpose are so-called UD tapes, that is to say unidirectionally arranged fiber strips, which can be arranged very well between or on the fiber semi-finished products.

A particularly simple conversion of the flat semi-finished fiber with matrix material is made possible by applying a SRIM process. Under a SRIM process, a structural-reaction-injection-molding, a process is understood in which semi-finished fiber products are placed in an open mold and then sprayed by means of a spray head with matrix material, preferably with polyurethane. The tool is closed after application of the matrix material and the matrix material hardened. In this case, the application of temperature and / or pressure may be advantageous. The SRIM process enables homogeneous matrix material application and thus contributes to increasing the quality of the fiber composite component to be produced.

Further according to the invention also a use of the method described above is given. This use provides for the production of trim components for a motor vehicle, in particular for a door trim.

Further details, features and advantages of the invention will become apparent from the following description and the figures. It shows:

1 a schematic representation of the individual process steps of an embodiment of the method according to the invention for producing a fiber composite component and

2 a graph in which the bending stiffness B _bv (t) is plotted for different wall thicknesses t _soll a fiber composite _component .

The present invention will be explained in detail with reference to an embodiment. In 1 only the aspects of the method according to the invention which are of interest here are shown, all other aspects have been omitted for the sake of clarity.

1 illustrates a method for producing a fiber composite component according to an advantageous embodiment of the invention. Shown are only the invention essential steps. Further process steps can complete the process.

First, fiber waste 1 , provided. The fiber waste 1 are unbonded, so resin-free or matrixmaterialfrei. In other words, it is dry fiber waste, such. B. Verschnittreste from the scrim production, production residues or Preformverschnitte. The fiber waste 1 contain at least one fiber material which preferably consists exclusively of carbon fibers.

In a first step A, the fiber waste 1 prepared, taking out the fiber waste 1 fibers 2 be uncovered under separation. This is done for example by punching or cutting the fiber waste 1 and opening them, the fibers 2 essentially not be damaged. There are prepared fibers 2 receive. These have an isotropic orientation, and can be anisotropically aligned by a subsequent carding process.

In step B, the fibers become 2 to a flat semi-finished fiber product 3 , which is preferably formed in the form of a nonwoven, further processed. The flat semi-finished fiber product 3 has a surface extension in the xz direction and has a smaller extent in the y direction. The extent of the semifinished fiber product 3 in y-direction here corresponds to the layer thickness or wall thickness of the semifinished fiber product 3 and is determined perpendicular to the xz plane.

The flat semi-finished fiber product 3 contains thus recycled carbon fibers, wherein a proportion of recycled carbon fibers at least 50 vol .-%, preferably 100 vol .-%, based on the total volume of the semi-finished fiber 3 used fibers 2 , is.

wobei B_bv(t) die Biegesteifigkeit des herzustellenden Faserverbundbauteils, E_bv das Elastizitätsmodul des herzustellenden Faserverbundbauteils, t_soll die Schichtdicke des herzustellenden Faserverbundbauteilsund und ν die Querkontraktionszahl (hier: 0,35) ist.Subsequently, the bending stiffness of the fiber composite component to be produced is determined. This is done by mathematical determination according to the following formula (1):

where B _bv (t) is the bending stiffness of the fiber composite component to be produced, E _{bv is} the modulus of elasticity of the fiber composite component to be produced, t _is the layer thickness of the fiber composite component to be produced, and ν is the transverse contraction number (here: 0.35).

From the bending stiffness of the fiber composite component to be produced can be given specification of a desired flexural rigidity z. B. the minimum number n _bv to be used on flat fiber semi-finished products 3 determined which produces at least the same good mechanical properties at a reduced weight of the fiber composite component.

This will be explained in more detail for the following example: As an example, a reference door trim for a motor vehicle, which is made of a glass fiber-polyurethane composite material. It has a bending stiffness of 19915.97 Nmm.

As semi-finished fiber, a nonwoven is used which contains a fiber material that consists of 100% recycled carbon fibers. It should be used in the fiber composite component by way of example five layers of the nonwoven fabric.

First, the fiber volume content φ (t) of the fiber composite component is determined, which, as described above, is to be produced from five fiber webs and a defined amount of matrix material (in the present case: polyurethane). The fiber volume content φ (t) is determined as follows:

Here n _{bv is} the number of fibrous webs to be arranged (in the present case: five), Y _{bv is} the basis weight of a fibrous web (this can be determined experimentally), ρ _{cf is} the density of the fibrous material, in the present case the density of the recycled carbon fibers (this value can be taken from the literature (see Schürmann, H .: Constructing with fiber-plastic composites, Springer-Verlag, Berlin / Heidelberg / New York, 2007 ) and t _is the desired wall thickness of the fiber composite component.

The result is the following fiber volume content φ (t):

It can be seen that the fiber volume content φ (t) is a function of two parameters, the number of fiber webs n _bv and the wall thickness t _{soll of} the fiber composite component to be produced. Ie. it can be determined either retroactively the necessary number of nonwoven fabrics n _bv given bending stiffness of the fiber composite component to be produced, or the minimum wall thickness t _{should be determined of} the fiber composite component depending on a defined number of fiber webs.

Next, the modulus of elasticity (modulus of elasticity) of the fiber composite component E _{bv to} be produced is determined:

This is the above-determined fiber volume content.

The values E _lit and φ _lit come from experiments. For this purpose, a fiber composite standard component with a defined number of semifinished fiber products, defined fiber material (amount and chemical nature of the fiber material), defined matrix material (amount and chemical nature of the matrix material) and defined layer arrangement (layering of semi-finished fiber products) was prepared, the chemical nature (fiber material, Matrix material, layer arrangement) of the fiber composite standard component was identical to the chemical nature of the fiber composite component to be produced. The fiber composite standard component serves as a template for determining the modulus E _lit at a defined fiber volume content φ _lit , which can be determined by tensile / bending tests. In the above equation, the modulus of elasticity is taken from the literature (see Schürmann, H .: Constructing with fiber-plastic composites, Springer-Verlag, Berlin / Heidelberg / New York, 2007 ).

Next, the mass of recycled carbon fibers m _cf in the fiber composite component to be produced is determined. This is needed for the total mass. The mass of recycled carbon fibers m _cf in the fiber composite component is as follows: m _cf = n _bv Y _bv A, where A is the area of the fiber composite component:

Subsequently, the mass fraction of matrix material ψ (in the present case: polyurethane) is determined. The mass fraction of matrix material can then be used to determine the mass of the matrix material in the fiber composite component:

Here, φ is the previously determined fiber volume content φ (t), ρ _{cf is} the density of the fiber material, in this case the density of the recycled carbon fibers in the semifinished fiber article, for example 3 and ρ _pu the density of the matrix material (these values are from the literature; Schürmann, H .: Constructing with fiber-plastic composites, Springer-Verlag, Berlin / Heidelberg / New York, 2007 ).

With the mass fraction ψ, the mass of matrix material m _pu in the fiber composite component can now be determined:

The values are from the above equations. Thus, the respective masses of matrix material and recycled carbon fiber are determined and the total mass of the reference composite fiber component can be determined from the sum of the two individual masses: m _pl = m _cf + m _pu , m _pl = 384 g + g = 2039.6 g 2423.5.

At the end, the bending stiffness of the reference fiber composite component B _bv (t) is determined.

Included here are the modulus of elasticity E _bv , the nominal wall thickness t _soll , and the transverse contraction number ν of the fiber composite component (here: 0.35).

Subsequently, the calculation is repeated for different combinations of different wall thicknesses t _soll and different number of nonwoven fabrics n _bv (variation of wall thicknesses of, for example, 1 mm to 3.5 mm in 0.2 mm increments and 1-7 layers of nonwoven fabric). The resulting flexural stiffnesses are then compared to the given flexural stiffness for the corresponding glass fiber-polyurethane composite template member. So the possible combinations can be determined.

2 is a graph in which the bending stiffness B _bv (t) is plotted for different wall thicknesses t _soll a fiber composite _component . The graph shows three curves. Curve A is the curve of a reference fiber composite component of glass fibers as a fiber material and polyurethane as a matrix material. Curve B is the curve of a fiber composite component of a nonwoven fabric according to the invention as a fiber material and polyurethane as a matrix material. Curve C is the curve of a fiber composite component made of two fiber webs according to the invention as fiber material and polyurethane as matrix material. With the number of fiber webs, the bending stiffness B _bv (t) of the fiber composite component increases. Out 2 It can be seen that with a wall thickness of, for example, 3.4 mm, the bending stiffness of a fiber composite component from a layer of nonwoven fabric corresponds to the bending stiffness of the fiber composite component formed from glass fibers. It is clear that when using two nonwoven fabrics instead of just one nonwoven, the wall thickness t _{soll can be} reduced to about 2.4 mm (intersection on curve C).

For example, if the desired bending stiffness is 30000 Nmm (see the horizontal line in the graph in 2 ), this is achieved in a fiber composite component with two fiber webs according to the invention and polyurethane as matrix material with a wall thickness of about 2.65 mm. When using only one fiber fleece (see dashed line in the graph in 2 ) would have a wall thickness of about 3.8 mm are provided.

In this case, the wall thickness t _{soll can} again be used to determine the number of fiber webs to be used to obtain a desired bending stiffness via the following formula:

The calculations are not dependent on the matrix material used. It can also use any other matrix material. Furthermore, it does not have to be fiber webs, it can also be calculated other semi-finished fiber products with this approach.

The correspondingly determined number of semifinished fiber products 3 will, as in 1 shown in step C on top of each other to a stack 4 arranged.

In step D, the insertion of the stack takes place 4 into a tool. The tool has an upper mold half 5 and a lower tool half 6 on, with the two tool halves 5 . 6 between them a gap 7 define. At the upper half of the mold 5 is a spray head 8th for application of a matrix material 9 (Resin, polymer) provided. The semi-finished fiber products 3 are then with matrix material 9 soaked.

Step E illustrates the molding process of the fiber composite component. The tool has been closed, leaving inside the stack 4 a certain pressure and possibly also an increased temperature act. As a result, the semi-finished fiber stack 4 reshaped and the matrix material 9 hardened.

In step F, the tool is opened. The resulting fiber composite component 10 can be removed from the mold.

Advantageously, the fiber composite component produced is 10 a trim component for a motor vehicle, in particular a door trim. The fiber composite component produced by the method described above 10 Contains recycled carbon fibers and therefore has a low weight with very good mechanical properties. The use of recycled carbon fibers protects raw material resources, reduces disposal costs and avoids the production of waste. The method is simple, without high technical complexity and thus a cost effective.

The foregoing description of the present invention is for illustrative purposes only, and not for the purpose of limiting the invention. Various changes and modifications are possible within the scope of the invention without departing from the scope of the invention and its equivalents.

LIST OF REFERENCE NUMBERS

1

fiber waste

2

fibers

3

Semi-finished fiber

4

stack

5

upper mold half

6

lower mold half

7

gap

8th

spray nozzle

9

matrix material

10

Fiber composite component

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102005026889 A1 [0002]

Cited non-patent literature

• Schürmann, H .: Constructing with fiber-plastic composites, Springer-Verlag, Berlin / Heidelberg / New York, 2007 [0038]
• Schürmann, H .: Constructing with fiber-plastic composites, Springer-Verlag, Berlin / Heidelberg / New York, 2007 [0043]
• Schürmann, H .: Constructing with fiber-plastic composites, Springer-Verlag, Berlin / Heidelberg / New York, 2007 [0046]

Claims (9)

Method for producing a fiber composite component ( 10 containing recycled carbon fibers ( 2 ), in particular a fiber composite component ( 10 ) for a motor vehicle, comprising the steps of: - providing flat semi-finished fiber products ( 3 ) containing recycled carbon fibers ( 2 ), with a proportion of recycled carbon fibers ( 2 ) at least 50 vol .-%, based on the total volume of the semi-finished fiber ( 3 ), - producing a fiber composite standard component with a defined number of fiber semi-finished products ( 3 ), defined fiber material, defined matrix material and defined layer arrangement, - determining the bending stiffness of the fiber composite component ( 10 ) according to the following formula (1):

where B _bv (t) is the bending stiffness of the fiber composite component ( 10 ), E _{bv is} the modulus of elasticity of the fiber composite component ( 10 ), t _should the layer thickness of the fiber composite component ( 10 ) and ν is the transverse contraction number, where E _{bv is determined} by the following formula (2):

where E _{lit is} the modulus of elasticity of the fiber composite standard component, φ _{lit is} the fiber volume content of the fiber composite standard component and φ (t) is the fiber volume content in the fiber composite component ( 10 ), - arranging a number of flat semi-finished fiber products ( 3 ), which gives the desired bending stiffness B _bv (t), - impregnating the flat semi-finished fiber products ( 3 ) with matrix material ( 9 ) and - curing the matrix material ( 9 ). A method according to claim 1, characterized in that the flat semi-finished fiber products ( 3 ) Fiber webs are. A method according to claim 2, characterized in that the nonwoven fabrics have an isotropic or anisotropic fiber orientation. Method according to one of the preceding claims, characterized in that the flat semi-finished fiber products ( 3 ) as the only fiber material recycled carbon fibers ( 2 ) contain. Method according to one of the preceding claims, characterized in that depending on the desired bending stiffness B _bv (t) of the fiber composite component ( 10 ) a minimum number of planar semi-finished fiber products ( 3 ) is determined by the following formula (3):

where n _{bv is} the number of flat semifinished fiber products to be arranged ( 3 ), t _should the wall thickness of the fiber composite component ( 10 ), φ (t) the fiber volume content in the fiber composite component ( 10 ), ρ _φ the density of the fibers in the fiber composite component ( 10 ) and Y _bv the basis weight of the semifinished fiber product ( 3 ), where φ (t) is determined by the following formula (4):

where n _{bv is} the number of semifinished fiber products to be arranged ( 3 ) Y _{bv is} the basis weight of a semifinished fiber product ( 3 ) and ρ _cf the density of the fiber material in the semi-finished fiber product ( 3 ). Method according to one of the preceding claims, characterized by a step of determining a minimum wall thickness of the fiber composite component ( 10 ) using the following formula (5):

where φ (t) is the fiber volume content in the fiber composite component ( 10 ) and is determined by the following formula (4):

where n _{bv is} the number of semifinished fiber products to be arranged ( 3 ) Y _{bv is} the basis weight of a semifinished fiber product ( 3 ) and ρ _cf the density of the fiber material in the semi-finished fiber product ( 3 ). Method according to one of the preceding claims, characterized by an introduction of at least one reinforcing element on and / or between the planar semi-finished fiber products ( 3 ). Method according to one of the preceding claims, characterized in that the fiber composite component ( 10 ) is produced by a SRIM process. Use of the method according to one of the preceding claims for the production of trim components for a motor vehicle, in particular for a door trim.

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