EP3704397A1

EP3704397A1 - Component for absorbing impact force

Info

Publication number: EP3704397A1
Application number: EP18796873.0A
Authority: EP
Inventors: Bernd Wohlmann; Christian Hunyar; Markus Schneider
Original assignee: Teijin Carbon Europe GmbH
Current assignee: Teijin Carbon Europe GmbH
Priority date: 2017-10-30
Filing date: 2018-10-26
Publication date: 2020-09-09
Also published as: JP2021501257A; CN111328366A; US20200340544A1; WO2019086348A1; JP7428651B2

Abstract

The invention relates to a component in the form of a crash element made of a fibre composite material, the wall of which is constructed at least predominantly from bundles of carbon fibres. The carbon fibre filaments are arranged parallel to one another within the fibre bundles, and the bundles are embedded in a polymer matrix. Within the wall of the component the bundles are distributed uniformly and have a substantially isotropic orientation as considered perpendicularly to a first and/or second surface.

Description

Component for absorption of impact energy

Description:

The invention relates to a three-dimensional, formed as a body member made of a fiber composite material for arrangement between a first shock element and a second shock element and for the absorption of impact energy due to an acting between the first and second impact element impact stress.

The protection of vehicle occupants of a motor vehicle as well as the protection of persons and objects located in the vicinity of the vehicle in collision cases is an important aspect in the design and manufacture of a motor vehicle. It is important in a safe design of a motor vehicle in the event of a collision that a vehicle deceleration or a force acting on the vehicle occupants, while occupant restraint systems develop their effect, do not exceed certain thresholds in the course of the collision.

In a collision of the motor vehicle there is a relationship between an effective mass of the colliding vehicle, a deceleration of the colliding vehicle and a force in which a body structure support, which is often referred to in this context as crash structure or deformation element, by plastic, elastic deformation or brittle fracture

progressively failed. Such a deformation element, for example, between a bumper cross member and a frame side member of the

Motor vehicle mounted.

A possible by the deformation element degradation of the collision energy is thereby by a force curve over an available

Deformation determined. At the beginning of a collision is a high Speed of the vehicle effectively, so that a relatively high kinetic collision energy or impact energy is broken down and the

Body structure including a body structure carrier or

Deformationselements must be designed such that the

Body structure support failed at an adjusted strength level.

Body structure or deformation elements are often designed so that they fail collision energy absorbing in the collision load case of the motor vehicle. Body structural support made of metallic materials are designed so that they deform plastically suitable at a certain level of force over a designated route.

There are widespread body structural supports that use metal tubes that are compressed in a longitudinal collision. The metal pipes,

For example, pipes made of aluminum, provide a strong connection between the bumper cross member and the vehicle. However, the specific energy absorption (kJ / kg) of metal tubes when compressed is not particularly high. Further, the initial force required for a metal tube to be compressed longitudinally may be too large for many situations.

In the case of a body structure carrier or deformation element

Carbon fiber reinforced plastic or other fiber reinforced plastic hollow sections have been proposed, for example

for example, have a rectangular profile. In the case of the failure mechanism "crushing", a more or less complete disintegration (pulverization or fragmentation or also called fragmentation) of the body structure carrier takes place predominantly in the

Brittle fracture. This failure mechanism works especially in a frontal impact, in which the force on the carrier perpendicular to a Carrier cross section is. The amount of force per area of the deformation profile cross section in the plane perpendicular to the direction of the force which occurs in this failure mechanism is referred to as crash failure stress. In the publications DE 102012019923 A1, DE 102014016024 A1,

DE 102014206610, or EP 1366960 B1 discloses components for energy absorption or absorption of impact energy from fiber composite materials, in particular composite materials based on carbon fibers. These

Body structure supports or deformation elements can be produced, for example, by braiding, pultrusion or winding or, as described in EP 1366960 B1, by laminating together several fiber layers, for example multiple layers of fabric, preferably starting from continuous fibers. The in the mentioned writings

described components for energy absorption have z.T. a layered structure or laminate structure, but can also be prepared from discontinuous fibers according to DE 102014016024 A1 or contain areas with arbitrarily oriented fibers, as described in EP 1366960 B1. Overall, the components described in the aforementioned documents have a complex component structure.

Elements for energy absorption are also described in US 2005/0147804 A1, wherein these elements have a layered structure of fiber layers made of bundle-shaped filament yarns. The fibers are arranged so that their direction of extension parallel or obliquely to

Compressive load due to impact is that the fibers have a component in the direction of impact loading. Moreover, in the energy absorption elements of US 2005/0147804 A1, the density of the fibers increases from one end of the element to the other. JP 06-264949 describes elements for energy absorption consisting of

fiber-reinforced synthetic resins are constructed, are mixed in the short fibers. The elements for energy absorption of JP 06-264949 have a cylindrical shape, wherein the wall of a cylindrical portion is designed so that the wall thickness increases from one end to another end. In the examples, JP 06-264949 goes over

Injection molding process prepared elements with a polypropylene matrix were mixed in the glass fibers with a fiber length of 3 mm and in a concentration of 30 wt .-%.

EP 3104036 A1 describes structures of fiber composite materials with a thermoplastic matrix for shock absorption or for energy absorption. The structures are usually designed as hollow profiles and may comprise bündiförmige reinforcing fibers. The fibers may be carbon fibers embedded in the thermoplastic matrix. The fibers may preferably be oriented two-dimensionally randomly in a surface plane. To produce the fiber composite materials, reinforcing fibers can be cut, then opened and the opened reinforcing fibers then mixed with a fibrous or particulate thermoplastic.

Subsequently, the mixture is pressed under pressure and heat to a fiber-reinforced thermoplastic semifinished product. One or more such semi-finished layers are stacked on top of each other to form the hollow profile.

Because of the high viscosities of thermoplastic matrices, the uniform impregnation of the fibers with the

thermoplastic matrix and the homogeneous distribution of the fibers in the matrix as a basis for uniform mechanical properties difficult. In addition, the layered structure, when impacted in a direction parallel to the layers, may result in delamination of the layers, associated with the detachment of large contiguous areas of material, which significantly reduces the specific impact energy impartation, or associated with the buckling of so weakened areas of the component , which leads to the sudden failure of the component and a very low impact energy consumption. The present invention has for its object to provide a structurally simple and easy to manufacture component for absorbing energy in the event of impact load. The component should have a high specific impact load

Have energy absorption. In addition to the component in the event of a shock stress initial peak loads, as they are observed in particular in deformation elements made of metallic materials, be reduced and certain thresholds in the course of

Collision / impact load must not be exceeded.

The object is achieved by a three-dimensional, formed as a body member made of a fiber composite material based on carbon fibers for the arrangement between a first shock element and a second shock element and for the absorption of impact energy due to an acting between the first and second shock element impact stress having an impact direction having the component

at least a first end and a second end,

a longitudinal direction extending between the ends, which in the

Can be arranged essentially in the direction of impact,

a first surface and a second surface and a wall having a wall thickness extending between the first and second surfaces,

- Wherein the wall at least for the most part from bundles of

Carbon fibers within which the carbon fiber filaments constituting the carbon fibers are arranged parallel to each other, - wherein the bundles and the carbon fibers constituting the bundles are embedded in a polymer matrix consisting predominantly of one or more cross-linked polymers,

- wherein the bundles are distributed substantially uniformly over the wall thickness, when viewed in a direction perpendicular to the first and / or second surface are substantially isotropically aligned and viewed parallel to the first and / or second surface (8, 9), the bundle angle of intersection form with a part of the first and / or second surface (8, 9), wherein the bundles are distributed parallel to the first and / or second surface (8, 9) within the component so that the majority of the cutting angles is within a range , in which the angles of intersection in the West are evenly distributed between 0 ° and 90 ° up to predominantly present

Cutting angles greater than 1 °.

wherein the fiber volume fraction of the carbon fibers in the wall is in the range between 35% by volume and 70% by volume,

- The bundles of carbon fibers have a length in the range between 3 mm and 100 mm and

the component being obtainable by a process comprising producing a fiber preform from the bundles of carbon fibers, and optionally by subsequently introducing a matrix system into the fiber

Fiber preform by injection, infusion infiltration or pressing.

The component should be designed as a body in a viewing direction parallel to the longitudinal extent. The term body includes both a profile, semi-profiles or other geometries whose cross-section may vary along the longitudinal axis. The body may be hollow, solid and / or partially filled and / or its longitudinal extent may be subdivided by means of intermediate pieces. Furthermore, the body may have different wall thicknesses, include reinforcing elements and / or have recesses. The body that forms the component may be constructed in one piece (in one piece) or from a plurality of partial bodies. The part bodies may also have different cross sections, be hollow, solid and / or partially filled and different

Have wall thicknesses and / or geometries.

The component can also be referred to as a deformation element.

The bundles of carbon fibers may also be referred to as carbon fiber bundles, reinforcing fiber bundles, or bundles only. The component can also be formed without the subsequent incorporation of the components of a matrix system (eg a thermosetting matrix resin). In this embodiment, the fiber bundles and thus the component itself already have so much polymer matrix that an additional introduction of

Matrix material (a matrix system) for component manufacturing is not required. In such a case, the component, for example, by activating the

Components of the polymer matrix are produced by means of pressure and heat.

The polymer matrix (in which the fiber bundles are embedded) consists for the most part of one or more crosslinked polymers. To a lesser extent, the polymer matrix may also comprise partially crosslinked polymers.

For example, the polymer matrix can be a predominant proportion of a fully crosslinkable duromer and a small proportion of a thermoplastic

Resin system and / or additives. Preferably

thermoplastic behaving thermosets used. In another

Embodiment, the polymer matrix consists of a conglomerate of epoxy with thermoplastic portions.

The matrix system is preferably one in the optional embodiment

Polymer matrix system, which consists for the most part of one or more crosslinked polymers (for example, a thermosetting matrix resin). For component production, the matrix system preferably hardens.

Preferably, the matrix system (optionally in addition to

Part manufacturing can be added) for the most part of one or more crosslinked polymers. To a lesser extent, the matrix system may comprise fully or at least partially crosslinked polymers.

For example, the matrix system can have a predominant proportion of a fully crosslinkable duromer and a small proportion of a thermoplastic resin system and / or additives. It is also possible to use thermoplastically behaving thermosets. In a further embodiment The matrix system consists of a conglomerate of epoxy with thermoplastic components.

By choosing the polymer matrix and the matrix system, the component over a wide temperature range advantageously approximately constant

Properties on. Temperature dependent fluctuations in the

Energy absorption (such as occurs with the use of thermoplastics) can be advantageously avoided. Considering a theoretical rectilinear extension of the fiber bundles beyond the first and / or second surface of the component, this line forms angles with the first and / or second surface of the component. At a

Considering a sufficiently small and flat region of the first and / or second surface of the component (part of the first and / or second surface), the majority of the bundles between the first and / or second surface forms so-called cutting angles with the first and / or second Surface off. The cutting angles of the fiber bundles are in a range in which the cutting angles in the West are uniformly distributed between 0 ° and 90 ° up to an arrangement of the fiber bundles, in which the cutting angles predominantly an angle of greater than 1 °, preferably greater than 2 ° and more preferably greater than 3 °. In the case of a distribution of the fiber bundles, which is predominantly isotropic when considered parallel to the first and / or second surface, the angles of intersection essentially all have a value between 0 ° and 90 °, wherein no value is to be represented much more frequently or less frequently. Lying the

Fiber bundles relatively parallel to the first and / or second surface before, the majority of the fiber bundles have cutting angles greater than 1 °. Consequently, the vast majority of the fiber bundles are not substantially parallel to the surfaces of the component in the component. It should be clear that the fiber bundles can assume any arrangement within the defined range, but within the component, however, the vast majority of the fiber bundles has the selected arrangement. As a "predominant proportion", a proportion of about 70% to 100%, preferably from 80% to 95% and particularly preferably from 85% to 90% should be understood.

By the term "substantially all" it is meant that this is for 80% to 100%, preferably 85% to 95%.

For example, the fiber bundles are isotropic in the component and also

is isotropic with respect to the surfaces if the fibers of the fiber bundles have a short length and, in addition, the wall thickness of the component is greater than the fiber length. An example of this could be the use of fiber lengths of 3 mm for a component with a wall thickness of 5 mm. A non-isotropic distribution of the angles of intersection between the bundles of carbon fibers and the surfaces of the component, in which the angles of intersection of the majority of the bundles are greater than 1 °, arises in particular if the fiber length of the bundles is relatively large in relation to the wall thickness For example, with a fiber length of 50 mm and a wall thickness of 2 mm. Since the component can have different bundles with different fiber lengths and, in addition, different wall thicknesses within a component or even with different components are conceivable, the arrangement of the bundles varies in parallel to the surfaces between these two possibilities.

Preferably, the extension of the component in the longitudinal direction is greater than its extension perpendicular to the longitudinal direction.

The inventive three-dimensional, formed as a body member made of a fiber composite material between a first shock element and a second shock element, so for example between a bumper cross member and a frame side member of a motor vehicle, and in the event of a collision or between a first and second impact element acting impact stress absorbing impact energy. It turns out that the component according to the invention leads to a uniform absorption behavior, which can be recognized by the force curve over the deformation path, wherein the peak loads in the initial phase of an impact load are comparatively low. At the same time, a high specific energy absorption (kJ / kg) can be realized with the component according to the invention in comparison to components or deformation elements made of metallic materials. The component according to the invention thus provides a solution which enables a defined energy absorption to a constant level over an adjustable long deformation distance. The actual energy level can be due to the geometric design of the component (especially by the

Wall thickness). In addition, the isotropic

Material structure of the component, even with shock loads that do not extend axially to the length of the component, a defined, constant

Energy intake.

Also compared to deformation elements made of fiber composites, the layered structure of layers of a laminated one another

Having fiber composite, shows a comparable or higher level of specific energy absorption. For components or

Deformation elements with a layered structure, in the event of a failure, at least in part result in a delamination of the layers, ie a peeling or breaking apart of the layers from one another, accompanied by a lower resultant force level. In contrast to such components or deformation elements with a layered structure, such a failure in the present component or deformation element can not take place, as viewed in a direction perpendicular to the thickness of the wall or parallel to the first and / or second surface of the component of the predominant Part of the bundles between an isotropic alignment and an alignment, in the bundles are arranged substantially not a cutting angle greater than 1 ° to the first and / or second surface of the component. This means that there is no layered structure, but a penetration of different levels of the wall of the component by the bundles, so a

Entanglement of the fiber structures is present.

Finally, the bundle, and in particular its substantially isotropic distribution, is substantially uniform over the wall thickness

Alignment when viewed in a direction perpendicular to the first and / or second surface ensured that when impact load a

uniform failure occurs without peak loads in the initial phase of shock loading.

Without wishing to be bound by theory, it is assumed that the fact that the fiber composite material and thus the wall of the

The component according to the invention is constructed, at least for the most part, from bundles of carbon fibers, and the orientation of the fiber bundles required according to the invention is the cause of a high specific energy absorption. In the case of an impact load and a component failure caused thereby, the impact energy from the continuously acting impact force is dissipated in the failure zone initiated in this way in such a way that it is dissipated

Degradation energy is converted to create new surfaces between fibers and matrix. By the inventive reinforcing fiber structure of the fiber composite material, which not only parallel to the component surface has an isotropy, but also through the thickness of a strong

Ensuring entanglement of the fiber bundles can be achieved as the failure zone progresses across the entire component volume

Degradation energy density and thus a high specific energy absorption can be ensured. Similarly, the high fiber volume fraction of the carbon fibers in the wall in the range between 35 vol .-% to and 70 vol .-% is the cause of a high specific energy absorption of the component under impact load. It should be noted that at fiber volume fractions below 35 vol .-% the

Failure behavior of the component is under shock load dominated by matrix failure, i. The failure behavior is determined by a break or crack in the matrix and thus by an inter-fiber break. at

Fiber volume fractions above 35% by volume, the failure behavior is primarily due to failure at the interface between fiber and matrix, i. determined by a fiber break. The higher failure forces of the latter two failure modes compared to the first failure form generate a high density of degradation energy and thus a high specific dissipated energy and thus a high specific energy absorption in the material. On the other hand, above 70 vol.%, Sufficient distribution of the matrix in the component and wetting on the filament surfaces of the fiber bundles can no longer be guaranteed. It is also presumed that the fiber volume fraction is limited by the filament geometry at very high values, since with circular filament cross sections a densest circular packing in the cross-sectional plane along the fiber direction in the fiber bundle can not be exceeded. These mechanisms provide above 70 vol .-% fiber volume fraction for a poor fiber-matrix connection and thus a low specific

Energy dissipation in the component. In a preferred embodiment of the component according to the invention, the fiber volume fraction of the carbon fibers in the wall of the component is in the range from 45% by volume to 65% by volume.

According to the invention, the bundles of carbon fibers, i. the

Reinforcement fiber bundles, from parallel aligned

Carbon fiber filaments and have a length between 3 mm and 100 mm. Preferably, the length is in the range of 5 mm to 70 mm, and more preferably in the range of 10 mm to 50 mm. With regard to the achievable fiber volume fractions of carbon fibers in the wall of the component, In particular, to achieve proportions above 45 vol .-%, it is advantageous if the wall of the component according to the invention has a plurality of groups of reinforcing fiber bundles with mutually different lengths, so that overall the length of the reinforcing fiber bundles has a distribution. For example, reinforcing fiber bundles having a length of 20 mm, 30 mm and 50 mm may be combined with each other.

The bundles of carbon fibers, i. the reinforcing fiber bundles may be made of conventional carbon fiber filament yarns having e.g. 500 to 50,000 fiber filaments exist. However, it is advantageous if each reinforcing fiber bundle consists of 500 to 24,000 reinforcing fiber filaments. To achieve the most homogeneous possible distribution of the reinforcing fiber bundles in the component wall and to achieve the highest possible fiber volume fractions, the number of filaments in the bundles is particularly preferably in the range 500 to 6,000 and most preferably in the range of 1 .000 to 3,000.

In one embodiment, a multifilament reinforcing yarn may be used as

Carbon fiber yarn having a tenacity of at least 5000 MPa measured according to JIS-R-7608 and a tensile modulus of at least 260 GPa measured according to JIS-R-7608.

In order to achieve high fiber volume fractions in the component wall, in particular to achieve proportions of carbon fibers above 45 vol .-%, it has also been found to be advantageous if the wall a plurality of groups of reinforcing fiber bundles with mutually different numbers of

Has filaments, since this high packing densities of the bundles can be realized in the wall. For example, reinforcing fiber bundles can be combined with 3,000, 6,000 and 12,000 filaments. To achieve the required fiber volume fractions in the wall, the bundles constituting the wall of the component according to the invention preferably have one Width in the range of 1 mm to 20 mm and more preferably a width in the range of 1 mm and 10 mm. Likewise, it is high for achieving

Packing densities of the bundles, i. to achieve high fiber volume fractions in the component wall of above 45 vol .-%, further advantageous if the bundles as flat as possible a cross section perpendicular to the extension of

Having carbon fiber filaments in the bundle. Preferably, the bundles are ribbon-shaped and have a ratio of bundle width to bundle thickness of at least 25. The ratio of bundle width to bundle thickness is particularly preferably in the range from 30 to 150.

By appropriate selection of reinforcing fiber bundles with regard to their

Ratio of bundle width to bundle thickness, in terms of their length and in terms of the number of reinforcing fiber filaments can be realized particularly high packing densities of the reinforcing fiber bundles and thus particularly high fiber volume fractions in the component wall. In a very particularly preferred embodiment of the component, the bundles arranged in the wall of the component have different lengths and different numbers of filaments in addition to a flat cross-section. This leads to particularly high fiber volume fractions in the wall of the component.

For the application of the component according to the invention for the absorption of

Impact energy, i. As a deformation or crash element, a uniform material behavior over as large a range as possible

Environmental conditions such as temperature or humidity required. For automotive applications, different continuous operating temperatures apply depending on the manufacturer and application. A temperature window of -40 ° C to 120 ° C has been established for applications in engine or exhaust gas nearby areas. The glass transition temperatures of most thermoplastics that are relevant for the automotive industry are within this temperature range. For example, the glass transition temperatures are many in the automotive sector

used polyamides in the range of about 35 ° C and 60 ° C. Such Thermoplastics are therefore poor in a component for the absorption of

Impact energy with consistent properties can be used.

Of course, there are also thermoplastics with higher glass transition temperatures, for example thermoplastics of the PAEK family, such as e.g. Polyether ether ketones (PEEK), etc. However, these matrix materials are too expensive for large-scale automotive applications. For one thing, the costs are the

On the other hand, the high processing temperatures due to the high melting temperatures mean considerable consequential costs. Thermoplastics with a melting point above 250 ° C (preferably 220 ° C) are not suitable. In addition, all matrix materials that have a water absorption of greater than 5 wt .-%, preferably greater than 3 wt .-%, unsuitable for structural components in a vehicle. With increasing

Water absorption swells the components and the mechanical performance decreases. Consistent properties, such as consistent

Energy absorption values, with changing environmental conditions are therefore not achievable.

Preferably, therefore, the bundles are embedded in the component and the carbon fibers constituting the bundles in a polymer matrix, which consists for the most part of one or more partially or fully crosslinked polymers.

The polymer matrix preferably comprises at least 60% by volume, based on the matrix fraction, and particularly preferably at least 75% by volume, of one or more partially or fully crosslinked polymers. Other constituents of the polymer matrix may be, for example, thermoplastics in order to increase the impact strength of the component or other additives, for example the

Processability or the life of the component.

In an advantageous embodiment, the polymer matrix has a matrix material based on acrylate or methacrylate. In addition, you can

Polyester resins, vinyl ester resins or phenol-formaldehyde resins in the

Be contained polymer matrix. Preferably, the carbon fibers are included in the wall of the component

Viewing perpendicular to the first and / or second surface of the wall stretched before (see Figure 12).

As stated, the wall is at least predominantly composed of bundles of carbon fibers, within which the carbon fibers

constituent carbon fiber filaments are arranged parallel to each other, wherein the bundles and the carbon fibers constituting the bundles are embedded in a polymer matrix, which consists for the most part of one or more crosslinked polymers. This means that in fact the bundle structure is preserved in the finished component. Advantageously, the carbon fibers are stretched in the bundles, whereby a high level of Drucksteif ig values for the component according to the invention can be achieved.

This property of the component according to the invention is in the application of advantage, since at a shock load of the component or the deformation element, which is a failure of the component to form a crash zone, the material lying below the crash zone must withstand the compressive forces and must not fail. This high pressure stiffness is necessary, since it keeps the deformation in the support zone, which has not yet been damaged by failure (crushing), and thus prevents premature failure of the component by kinking or buckling. If the compressive stiffness in relation to the crash failure stress is comparatively low, otherwise the component would have to be made very thick or, in the worst case, it always fails due to kinking or buckling.

In the context of the present invention, a stretched configuration of the carbon fibers in the component is understood to mean that the carbon fibers are not curled or bent on their own and a change in the

Longitudinal extension of the carbon fibers only by the geometry of the component is conditional. The fiber bundles thus have kinks or corrugations neither in the longitudinal extent nor transversely to the longitudinal extension, which would not be due to the geometry of the component. In conventional fiber composites, such as those based on fabrics, nonwovens or sheet-molded compounds (SMC), the fibers are curved or wavy, so that the rigidity (E modulus) for tensile and especially for compressive loads are reduced , These reduced properties are disadvantageous in both static and dynamic loads. Such curved or wavy arrangements of the fibers can be made visible, for example, by X-ray examinations. For example, in the handbook of fiber composites / composites, Springer Verlag, 2014, 4th edition, page 253 in Figure 154 or page 270 in Figure 270, the X-ray images of an SMC component are shown. The

Reinforcing fibers were oriented and undulated by the flow of the viscous matrix during the manufacture of the SMC component during the filling process. The fiber bundles are not aligned along a straight line, but have in comparison to a significant curvature. In addition, the strong flow of the matrix and fibers during the filling process creates an inhomogeneous fiber distribution.

In comparison, the carbon fiber bundles according to the invention are distributed homogeneously over the component cross-section. Homogeneous distribution is understood here to mean that the fluctuation of the fiber volume fraction is less than ± 10% by volume for each sample of the component having a size of at least half the fiber bundle length of the component (eg for a cylindrical sample of 25 mm diameter and 2 mm Thickness with a component wall thickness of 2 mm and a fiber bundle length of 50 mm). In addition, the bundles are already deposited in the production of the preform essentially in the final geometry. During the injection and infusion process, only the flowable components will be added to the polymer matrix. A shift in the Carbon fiber bundle is excluded due to the fixation of the preform. Over this, the carbon fiber bundles retain their stretched orientation. This achieves high compressive stiffness values and avoids undesired failure at weak points, such as resin-rich zones or particularly severely deformed areas of the component.

The component can be produced in a simple manner by first producing from the bundles of carbon fibers a fiber preform, often also referred to as a preform. The already near-net shape fiber preform is inserted into a tool which has the negative or positive near net shape of the component. If the reinforcing fiber bundles already have enough matrix material, the addition of further matrix material is not necessary. In such a case, the matrix material can be activated, for example, for component production with pressure and heat. However, it can also be provided that additional matrix material (matrix system) is fed to the fiber preform by means of conventional methods. For example, the matrix material, i. the not fully or partially cured matrix resin, are introduced into the tool and thus in the fiber preform via infusion, infiltration, injection or pressing. Subsequently, with full or partial crosslinking of the polymeric matrix material (for example by curing a thermosetting matrix resin), the component is formed.

The production of the fiber preform can be carried out inexpensively and in a simple manner according to the method, as described, for example, in EP 2727693 B1, to the relevant disclosure of which reference is expressly made. The method of EP 2727693 B1 comprises the following steps:

Feeding at least one endless ribbon-shaped strand of binder-provided reinforcing fibers from a master onto a head, wherein the at least one strand has a strand width of at least 5 mm, and a concentration of the binder in the range of 2 wt .-% to 20 wt .-%, alternatively from 15 wt .-% to 75 wt .-% based on the weight of the ribbon-shaped strand having.

Spreading the at least one endless ribbon-shaped strand in a spreading unit arranged on the depositing head and conveying the at least one strand in the conveying direction by means of a first conveying device arranged on the depositing head to a longitudinal separating device arranged on the depositing head,

thereby stabilizing the at least one strand in the direction transverse to the conveying direction,

- Cutting the at least one strand in the longitudinal separator

along its longitudinal extent by means of at least one separating element into two or more sub-strands,

Conveying the partial strands in the conveying direction by means of a second conveying device arranged on the depositing head to a cutting unit arranged on the depositing head,

Cutting the partial strands by means of the cutting unit in

Reinforcing fiber bundles of defined length and

Depositing the reinforcing fiber bundles on a surface and / or on the surface deposited reinforcing fiber bundles and fixing the

Reinforcing fiber bundles on the surface and / or deposited on the surface reinforcing fiber bundles for forming the fiber preform, wherein between the storage head and surface, a relative movement for load-appropriate storage of the reinforcing fiber bundles is set on the surface.

For the preparation of the fiber preform are preferably bundles of

Carbon fibers are used, in which the carbon fibers are provided with a binder. This binder is a material by means of which e.g. by a heat activation and subsequent cooling of the

Fiber preform can be brought into a stable state, the one

Handling of the fiber preform in subsequent process steps allowed. The binder may then be a fiber preparation commonly applied to the filaments of the carbon fibers to provide improved processability and fiber closure, ie at least partially bonding the filaments together. such

Preparations are often based on epoxy resins or polyurethane resins.

The polymer matrix (in which the fiber bundles are embedded) preferably represents the binder or the preparation for the carbon fiber bundles. However, an increased content is required for producing the fiber preform for the component according to the invention, preferably in the range of 2 Wt .-% to 14% by weight and particularly preferably in the range of 3 wt .-% to 7 wt .-%, based on the total weight of the binder provided with carbon fiber yarn. Suitable binders here are thermoplastic or unhardened or partially cured thermoset polymers or even polymer compositions of these polymers. Suitable thermoplastic polymers are, for example, polyethyleneimine, polyetherketone, polyetheretherketone, polyphenylene sulfide, polysulfone, polyethersulfone, polyether ether sulfone, aromatic polyhydroxyethers, thermoplastic polyurethane resins or mixtures of these polymers. As uncured or partially cured thermoset polymers come

for example, epoxides, isocyanates, phenolic resins or unsaturated polyesters in question. It is advantageous if the provided with binder carbon fibers or the carbon fiber bundles at processing temperatures, as to

Production of the fiber preform, so when storing the bundles for

Fiber preform, ie usually at room temperature, prevail, are not sticky. However, at elevated temperatures the binder (s) should be tacky and result in good adhesion of the fiber bundles made therefrom. Such reinforcing fiber yarns or Strands of reinforcing fibers are described, for example, in WO 2005/095080, the disclosure of which is expressly referred to here. The local filament yarns are infiltrated with a binder composed of several different epoxy resins, these epoxy resins differ in a defined manner with respect to their properties such as epoxy value and molecular weight and with respect to their concentration. Also, WO 2013/017434, the disclosure of which is incorporated herein by reference, describes prepreg impregnated with a binder

Carbon fibers.

In an advantageous embodiment of the component according to the invention, the polymer matrix used in the component and / or the matrix system used, a fracture toughness, which increases by a maximum of 100% at a

Temperature change from 20 ° C to 100 ° C, measured according to ISO 13586. Components with such a matrix property have a high matrix brittleness. (The brittle the matrix, the lower the fracture toughness.) It is believed that by choosing the matrix material having such a fracture toughness, the component will delaminate upon application to the individual fiber bundles, thereby forming a large internal surface in the component, ultimately Transforming the collision energy into heat contributes. The polymer matrix used in the component may be the polymer matrix of the reinforcing fiber bundles and / or the matrix system optionally additionally added for the production of the component.

The component is, as stated, in a viewing direction parallel to

Formed longitudinally as a body. The training as a body is a self-supporting and against buckling loads stable structure. In this way, the impact energy over the deformation can be uniformly dissipated and a buckling of the component, creating another

Energy dissipation is terminated, at least largely avoided. In a preferred embodiment, the body when viewed parallel to the longitudinal direction of the component to a profile, more preferably to a

Wave profile, a zig-zag profile, an angle profile or a profile, which has a mixture of the aforementioned profiles act. However, it can also be any, even irregular profiles. Preferably, the inner and / or outer cross-section of the body has a wave shape, a zig-zag shape, an angle shape, a curve or a mixture of the aforementioned shapes. In a further preferred embodiment, the component may have as a body a closed hollow profile, which has a cavity extending between the first and second ends, wherein the first end and the second end are connectable to the first and the second impact element, and wherein the hollow profile has an outer and an inner cross-section and the first surface facing away from the cavity and the second surface facing the cavity. In this case, hollow profiles are preferred in which the inner and / or the outer cross section has a circular, elliptical, square or rectangular contour or a polygonal contour. Examples of such hollow profiles are as in EP 3104036 A1 or in the

US 2005/0147804 A1 find.

The component may have more than a first and a second end.

For example, the component may have three or more ends. to

Simplification is reported below from a first and a second end, without restricting the component to it.

In a preferred embodiment, the wall thickness of the component according to the invention over the extension in the longitudinal direction is constant (see Figure 2c). In a further preferred embodiment, the wall thickness of the component increases from the first to the second end of the component (see Figure 2d). In a hollow profile as the body of the component can preferably the inner and / or the outer Cross section along the extension to be constant in the longitudinal direction. Likewise, in a member having a hollow profile as a body, preferably the inner and / or outer cross-section may increase in a region between the first and second ends from the first to the second end of the composite component.

In the case where the inner and outer cross-sections are constant, a wall is obtained with a wall thickness constant from the first to the second end of the component. In this embodiment, the cross-sectional area of the wall over the extension of the component in the longitudinal direction is constant. Likewise, a constant wall thickness can be obtained if the inner and outer cross-sections increase in the same way from the first to the second end along the longitudinal extension. In this case, however, the cross-sectional area of the wall increases over the extension of the component in the longitudinal direction from the first to the second end of the component. Further advantageous embodiments of the component according to the invention are those in which the wall thickness increases in a region between the first and the second end from the first to the second end of the component. Further embodiments of the component provide that the wall of the component is made thicker and / or thinner only in some areas. Subregions whose wall is thicker within the subregion may have ribs, for example. Subregions whose wall is thinner within the subregion can be, for example, trigger regions which can be used to introduce force. Preferably, the component is constructed from a plurality of partial bodies.

For example, the component may consist of two body shells that

assembled (for example by means of connection by flanges) form the component. In the end use (for example in the vehicle), the component can be used individually or with several components as an absorption element for impact energy. When using a plurality of components, the components used may be the same or different and / or in Row next to each other, one above the other and / or arranged concentrically around a center.

In a preferred embodiment, in the case that the component is a closed hollow profile as a body, this component is constructed from two partial profiles, which are interconnected in the longitudinal direction to form the hollow profile.

Such sub-profiles, for example in the form of half-shells, are in a particularly simple manner via a process for producing a

Fiber preform or a preform to produce, since the reinforcing fiber bundles can be stored in the manufacture of the preform in an open mold. Preferably, the sub-profiles in the longitudinal direction on the side flanges, via which the sub-profiles are interconnected. The connection can preferably be effected by means of an adhesive, for example by means of a 2-component construction adhesive. The connection can also be effected by means of a clamping, screwing, welding and / or riveting surrounding the flanges on the outside, or by means of an auxiliary construction enclosing the flanges, as described for example in EP 3104036 A1. Preferably, the sub-profiles are positively and / or non-positively connected.

It is advantageous if the component has a region for initiating the impact energy at its at least first and / or second end. In the application of the component according to the invention, it is important that forms a failure zone controlled a failure zone in whose

Advancing through the component as much energy is absorbed. This can advantageously be achieved in that the impact force or impact energy in the often referred to as a crash element component is first introduced into a located at the end of the crash element area for initiating the impact energy, the so-called trigger area, for example, a chamfer the cross-sectional area (chamfer) can be. The exact geometric design of this area has proven to be less important. He does, however, have one Reduction of the wall thickness or the cross-sectional area of the wall include and is primarily a breaking point for a targeted failure. In the trigger area, an increased tension acts, as the same force acts on less material in the area of the bevelled tips, and the material fails.

According to the invention, the wall of the present component is composed at least predominantly of bundles of carbon fibers, within which the carbon fiber filaments constituting the carbon fibers are arranged parallel to one another. However, in a preferred case, the wall may additionally comprise at least one layer of unidirectionally oriented long fibers, wherein the at least one layer on at least one of

Surfaces or inside the wall can be arranged and extend between the first and the second end of the component. About such

Layers of unidirectionally oriented long fibers can be achieved in the application, for example, a further stabilization of the component against buckling. Preferably, the long fibers extend from the first to the second end of the component. At more than two ends extend the

Long fibers preferably between at least two ends of the component. Such long fibers preferably have fibers with a length of more than 10 mm and a width of more than 3 mm.

In an advantageous embodiment of the component according to the invention, the wall has on the first and / or second surface reinforcing elements which extend in the direction of the longitudinal direction of the component. such

Reinforcement elements may e.g. have the shape of ribs or lamellae which are applied to the surface, for example by adhering separately produced elements (see also Figure 2). The reinforcing elements may also be made of fiber composite material, but they may also be elements of, for example, metallic materials. In the case that the reinforcing elements made of fiber composite material, the

Reinforcement also integral with the component or the wall of the component connected and made together with the wall. For example, tapes of unidirectional fibers, such as unidirectional prepregs, may be laminated to the wall of the fiber preform and cured after injection of the matrix material together with the matrixed fiber preform to the component. Preferably, however, the reinforcing elements consist of the same bundles of carbon fibers, which were also used for the formation of the wall of the component.

In a further preferred embodiment, a permanently bearing element is integrated into the component, which is connectable to the first and the second impact element. This permanently bearing element is not destroyed in the event of a shock load together with the component, but

moved and / or deformed. By means of such elements can be taken to ensure that even after destruction of the component after a

Shock a connection between the first and the second

Impact element remains, so for example, the bumper cross member is still held on the frame side member of the motor vehicle. By way of example, the permanently supporting element may be a steel tube which is telescopically displaced in the component in the event of a crash or in the event of a shock load. It is also possible that several permanently supporting elements are integrated into the component.

The invention will be further described by way of examples, wherein the examples and figures are merely embodiments of the invention and should not be considered as limiting.

FIG. 1 schematically shows a comparison of the voltage-path curves between components not according to the invention and an exemplary embodiment of the component according to the invention in a crash.

FIGS. 2, 2a, 2b, 2c and 2d schematically illustrate possible embodiments of the component. FIGS. 1 and 3 to 11 show various crash data in curves for exemplary embodiments of the component. The x-axis represents the distance measured in mm. The y-axis indicates the force measured in kN. FIG. 1 shows a comparison of the pressure or stress-displacement characteristics of an aluminum component (curve A) in comparison to components made of fiber-reinforced plastics. The X-axis describes the path in mm, the Y-axis the pressure or the stress in MPa. For the components

Fiber-reinforced plastics is a non-inventive example of a thermoplastic with carbon fibers (curve B) and a component, according to an embodiment of the invention (curve C), wherein the carbon fibers having a mean cutting length of the fiber bundles of 50 mm in an isotropic fiber bundle distribution in the component templates. Both components made of fiber-reinforced plastic had the same geometry and were constructed from half-shells. The aluminum component consisted of a tube with a 66 mm inner diameter and 2 mm wall thickness. The geometries of the components were coordinated so that the results are comparable. It can be seen that the amplitude variation with respect to the path of the aluminum component is much greater than that of the

Amplitude fluctuations in the components made of fiber-reinforced plastics. In comparison to the fiber-reinforced non-inventive component

Plastic, the initial voltage amplitude of the failing component according to an embodiment of the invention is substantially lower. This has the consequence that at lower initial forces already kinetic energy in

Deformation energy is converted and so, for example, the following

Vehicle structures or vehicle occupants are protected against the action of high forces.

FIG. 2 shows an exemplary embodiment of a component 1 which is used for

Impact energy absorption can be used. The component 1 has a first end E1 and a second end E2 and, for example, a semicircular Cross-section, wherein the cross section changes along the longitudinal direction L. The component 1 may have a rib 2 (or a plurality of ribs), which may be provided on a first surface 8, for example. The rib can be made in one piece from the component 1 or attached as a further element on the component 1. For example, the rib 2 can be formed by the deposition of one or more slivers on the component 1. The component 1 may further preferably have recesses 3, such as holes. Through these recesses 3, advantageously, the weight of the component 1 can be reduced, without the length or width of the

To reduce component 1. Within the component flaps or covers 5 may be provided which divide the component 1 in its longitudinal extent L. The cover 5 can be designed so that they extend from one wall to the other wall and thus form a closure or they can extend only within the component 1, without the cover 5 has a contact with the other (opposite) wall side. The lid or flaps 5 can advantageously stabilize the component 1 and, for example, prevent kinking of the body 1 in the event of a shock. In the embodiment of Figure 2, the body 1 has a half-round profile 7, wherein the first end E1 has a smaller diameter than the second end E2. By means of flanges 6, the component 1 can be connected to other parts. The other parts may, for example, be further components 1 for the absorption of impact energy (of the same type or another type) or impact elements. By means of the flanges 6, the component 1 can be brought into positive and / or non-positive connection with the other parts, wherein an irreversible connection is preferred.

FIG. 2 a shows an embodiment of the component 1 as used for example 1. FIG. 2b schematically shows a section of the component 1. Shown is a part of a wall of the component 1 with the first surface 8. Fiber bundles for Formation of the component 1 are substantially isotropic when viewing a perpendicular S to the first surface 8. Furthermore, the fiber bundles when viewing a parallels W to the first surface 8 cut angle to the surfaces 8, 9th

FIG. 2 c schematically illustrates an exemplary embodiment of the component 1 in a simplified manner. In this exemplary embodiment, an external cross section 1 1 of FIG

Component at the first end E1 smaller than the outer cross-section 1 1 at the second end E2. Consequently, the cross section of the component 1 has increased over the longitudinal direction L. An inner cross-section 1 1 ^'of the component 1 may have changed from the first to the second end E1, E2 or remain the same. With a constant inner cross-section 1 1 ^' results in a change in the wall thickness of the component. 1 FIG. 2d schematically shows a further embodiment of the component 1 in a simplified manner. In this embodiment remains the

Outer cross section (not shown) of the component 1 from the first end E1 to the second end E2 constant. However, a wall thickness 10 of the component 1 at the first end E1 is greater than the wall thickness 10 ^'of the component at the second end E2.

FIG. 12 shows an X-ray image of a component with stretched fiber bundles. The component should preferably be at least 20% of the fiber bundles in FIG

Areas that are not determined by the given component geometry already as curved, which differ compared to an applied straight line of this maximum by 5 mm (preferably by 2 mm). Curvatures in the fiber bundles that do not result from the preform production but are forced and desired from the geometry of the component are determined by using the most obvious component edge as a reference. example 1

For example 1, a body according to an embodiment of the invention as a crash component, as shown in Figure 2a, produced. For the test result, the component was tested in a dynamic impact test. For this purpose, preforms were first produced so-called preforms. For this step, a carbon fiber yarn (Tenax HTS40 X030 12k 800 tex) with disability (according to the writings WO 2005/095080, WO 2013/017434) was divided into fiber bundles in the transverse and longitudinal direction. The fiber bundles were given a length of 50 mm and a width between 1 mm and 5 mm. These

Fiber bundles were formed into near-net shape preforms. For this purpose, the fiber bundles are applied to a preform tool, which already for the most part depicts the geometry of the end component. The method of application (manually or by means of a controlled track, e.g., a robot) is of minor importance as long as a uniform application of the bundles is produced. In the example, a fiber order is set to a

Fiber volume content in the component of 50 vol .-% with a maximum deviation of ± 5 vol .-% leads. In order to fix the fiber bundles at the respective job site, the preform tool can be designed with many small holes, which are acted upon by a suction flow. In this way, the fiber bundles are sucked in and fixed at the respective point. In the next step, this structure is heated and the binder unfolds its adhesive effect. Under certain circumstances, the structure can be compacted by an additional force perpendicular to the respective surface. After the binder has cooled again, the entire preform but also the individual fiber bundles are fixed at their local locations. The preforms were fixed in a steel mold by a resin infusion process (Resin

Transfer Molding, RTM) into two half-shell-shaped profile components (part bodies) with a constant wall thickness of 2 mm in the longitudinal direction and a partially semicircular cross-section processed. The fiber volume fraction of the partial bodies was 50%. As the resin infusion matrix system, an epoxy resin system (Huntsman Araldite LY 1564 / Aradur AD 22962) was used. After demoulding the profile components or the part body, they were tempered. The Partial bodies were trimmed with a diamond circular saw. Two of these half-shell-shaped part bodies were assembled in a glue jig and glued to laterally extending flat flanges with a 2-component construction adhesive (3M DP490). Subsequently, by

Abrading on one side of the component a force introduction structure (so-called.

Trigger) introduced in the form of a circumferential 45 ° bevel.

The component thus fabricated was attached to a flat, non-compliant steel baffle plate so that the longitudinal axis was perpendicular to the plate and the force application point faced outward. Subsequently, a carriage, which had a mass of 61 kg and a flat steel baffle plate in the direction of the component, so at 10 m / s on the component driven that it was destroyed along its longitudinal axis. During the destruction process, with a magnetic position transducer and a magnetostrictive displacement measuring system (Temposonics R series from MTS with a maximum travel length of 1000 mm), the path of the carriage on impact and with a load cell (Piezo KMD 9091 A from Kistler with max 400 kN) on the component, the force acting on the component is absorbed. In this case, a course of the force and the path over time with a sampling period of 4 s or frequency of 250 kHz was recorded. In Figure 3, the recorded force-displacement relationship of the various components is averaged (X-axis displacement in mm, Y-axis force in kN), where both the displacement and force data are numerically time-numerically denoted by channel frequency -Classes (CFC) 600 filter algorithm were filtered (according to SAE J21 1). There was a force plateau at (50 +/- 5) kN in this curve. The absorbed energy per mass of the component material (dissipated

Energy density) amounted to 71 J / g. The result showed that in the failure zone initiated by the trigger, the impact energy from the continuously acting impact force was dissipated by being converted into degradation energy to create the new surfaces between the fiber and the matrix. Due to the largely constant course of the failure zone, a uniform course of the failure force and the associated uniform energy absorption developed. Strong amplitude fluctuations leading to a Endangerment of, for example, vehicle occupants, are not available. The value of dissipated energy density was within or beyond the values of other prior art materials

Table 1 shows.

Comparative Example 1 of Table 1 is a component of carbon fibers with a cut length of 50 mm, wherein the component was produced according to the description of Example 1, with the difference that polyamide 6 was used as the matrix material. As explained with reference to FIG. 1, such a component has the disadvantage that the initial amplitude is substantially higher than for a component according to an exemplary embodiment of the invention. In addition, thermoplastic matrix systems show a temperature-dependent crash behavior, which is not desirable. In addition, components with a high proportion of thermoplastics tend to absorb water, which reduces the life of such components due to swelling of the components. It can easily be seen that the shortening of the service life, especially at the end of the life cycle, influences and reduces the crash properties of the component.

The temperature dependence of components with a thermoplastic matrix is shown in FIG. 11.

The X-axis of Figure 1 1 describes the path in mm, the Y-axis describes the force in kN. The curve D describes the crash behavior of a component constructed according to Comparative Example 1 at -30 ° C. The curve E describes the crash behavior of a component constructed according to Comparative Example 1 at -20 ° C, the F curve at 50 ° C and the G curve at 90 ° C. Such a temperature range is common especially for components as crash elements in the automotive sector. A consistent failure behavior, which is largely independent of the temperature, can therefore with thermoplastics as the main

Matrix material can not be achieved.

Comparative Example 2 of Table 1 is an aluminum tube, as it was already used for the experiment of Figure 1. Example 2

As described in Example 1, a component was made from preforms containing fiber bundles of length 25 mm and width of 1 mm to 5 mm. In contrast to Example 1, consequently fiber lengths of 25 mm were used instead of 50 mm. The wall thickness of the component corresponded to that of

Example 1. The component was destroyed as indicated in Example 1. This resulted in a force curve shown similar to Figure 3 with a force plateau at (55 +/- 5) kN. The absorbed energy per mass of the component material was 72 J / g. The course of the force-displacement curve and the specific

Energy density did not differ significantly from the case in Example 1 with 50 mm cut length. A separate figure for example 2 was therefore not created.

Example 3

As described in Example 1, components were made from preforms containing fiber bundles of length 50 mm and width of 1 mm to 5 mm. Unlike in Example 1, however, two components were manufactured, the one

Wall thickness of 3 mm or 4 mm had. The components were destroyed as indicated in Example 1 and the results worked up as indicated in Example 1. This resulted in a force curve as in Figure 4 for the component with 3 mm wall thickness and in Figure 5 for the component with 4 mm wall thickness with a power plateau at (70 +/- 5) kN for 3 mm wall thickness and (90 +/- 7 ) kN for 4 mm wall thickness. The absorbed energy per mass of the component material was 70 J / g for 3 mm wall thickness and 73 J / g for 4 mm wall thickness.

It was found that the failure force was adjustable by the wall thickness of the component and scaled largely linearly with the cross-sectional area of the wall, whereby the dissipated energy density remained largely constant. Advantageously, therefore, an adjustable force profile during the

Deformation of the component possible.

Example 4

As described in Example 1, components were made from preforms containing fiber bundles of length 50 mm and width of 1 mm to 5 mm with a wall thickness of 2 mm. The components were as in Example 1

was destroyed and the data was given as in Example 1

edited. Unlike in Example 1, however, the components were tempered to -30 ° C, 70 ° C and 1 10 ° C until 30 s before the experiments. This resulted in the component temperatures -30 ° C, 50 ° C and 90 ° C during the crash test. In this case, the force profiles were shown in the curves of Figure 6 (-30 ° C), Figure 7

(50 ° C) and Figure 8 (90 ° C) with a force plateau at (40 +/- 5) kN for a component temperature of -30 ° C, (45 +/- 5) kN for a component temperature of 50 ° C and (45 +/- 5) kN for a component temperature of 90 ° C. The absorbed energy per mass of the component material was 54 J / g for one

Component temperature of -30 ° C, 60 J / g for a component temperature of 50 ° C and 60 J / g for a component temperature of 90 ° C. Advantageously, it was found that the temperature dependence of the failure force and the dissipated energy density is not very pronounced. This was especially evident in comparison to

Carbon fiber composites with thermoplastics as found in the prior art and as studied in Comparative Example 1, Figure 11.

Example 5

As described in Example 1, components were made from preforms, which fiber bundles of length 50 mm and the width of 1 mm to 5 mm at a Wall thickness of 2 mm had. However, the fiber volume fraction of the components according to Example 5 was once 40% and once 45%. The components were destroyed as described in Example 1 and the data prepared as described for Example 1. The force profiles of the curves were shown in FIG. 9 for 40% fiber volume fraction and FIG. 10 with 45% fiber volume fraction with a force plateau at (45 +/- 10) kN for a fiber volume fraction of 40% and at (45 +/- 5) kN for a fiber volume fraction of 45%. The energy absorbed per mass of the component material was 64 J / g for a fiber volume fraction of 40% and 61 J / g for a fiber volume fraction of 45%. While at 40% fiber volume fraction, the fluctuations in the plateau region of the force-displacement curve were still relatively large, 45% already formed

relatively flat plateau. So here was the advantageous failure of the material. The respective higher force level of the plateau value of the experiment with a fiber volume content of 50% from Example 1 in comparison with the value at 45% and in comparison with the value at 40% fiber volume fraction showed that a smaller fiber volume fraction the failure properties (force and dissipated energy density) lowered, since less per component volume

Dissolution processes between fiber and matrix material took place.

LIST OF REFERENCE NUMBERS

A curve component aluminum

B curve component carbon fibers with thermoplastic

C curve component according to an embodiment of the invention

D Curve Comparative Example Component with Thermoplastic

E Curve Comparative Example Component with Thermoplastic

F Curve Comparative Example Component with Thermoplastic

G Curve Comparative Example Component with thermoplastic

1 component (impact element, crash structure)

2 rib

3 recess / hole

4 wave profile

5 lid / flap

6 flange

7 Semicircular profile

8 first surface

9 second surface

10, 10 ^' wall thickness

1 1 outer cross section

1 1 ^' inner cross section

E1 first end

E2 second end

L longitudinal direction

S perpendicular to the surface 8, 9

W Parallel to the surface 8, 9

Claims

Component for absorption of impact energy

claims:

1 . Three-dimensional formed as a body member (1) from a

Carbon fiber-based fiber composite material for placement between a first impact element and a second impact element and for absorbing impact energy due to an impact stress acting between first and second impact elements which has an impact direction;

- Wherein the component has

at least a first end (E1) and a second end (E2),

a longitudinal direction (L) extending between the ends, which can be arranged substantially in the direction of impact,

a first surface (8) and a second surface (9) and a wall having a wall thickness (10, 10 ^' ) extending between the first and second surfaces,

characterized in that the wall is at least predominantly composed of bundles of carbon fibers within which the carbon fiber filaments constituting the carbon fibers are arranged parallel to one another,

in which the bundles and the carbon fibers constituting the bundles are embedded in a polymer matrix consisting predominantly of one or more cross-linked polymers,

- wherein the bundles over the wall thickness (10, 10 ^' ) substantially

are uniformly distributed when viewed in a direction perpendicular (S) to the first and / or second surface (8, 9) are substantially isotropically aligned and when viewed parallel to the first and / or second surface (8, 9), the bundle angle of intersection with forming a part of the first and / or second surface (8, 9), the bundles being parallel to the first and / or second surface (8, 9) considered within the component are distributed so that the

most of the cutting angles are in a range in which the cutting angles in the West are uniformly distributed between 0 ° and 90 ° up to prevailing cutting angles that are greater than 1 °,

- where the bundles of carbon fibers have a length in the range

between 3 mm and 100 mm and

wherein the component (1) is obtainable by a process comprising producing a fiber preform from the bundles of carbon fibers and optionally by subsequently introducing a matrix system into the fiber preform by injection, infusion, infiltration or compression and crosslinking of the matrix system Matrix system consists for the most part of one or more crosslinked polymers.

2. Component (1) according to claim 1, characterized in that the

Carbon fibers present in the wall when viewed perpendicularly (S) to the first and / or second surface (8, 9) stretched.

3. Component (1) according to claim 1 or 2, characterized in that the fracture toughness of the polymer matrix at most by 100% with a change in temperature from 20 ° C to 100 ° C - measured according to ISO13586 - changes.

4. component (1) according to one or more of claims 1 to 3, characterized

in that the inner and / or the outer cross-section (11, 11 ^' ) of the body has a wave shape, a zig-zag shape, an angle shape, a curve or mixtures of the aforementioned shapes. Component (1) according to one or more of claims 1 to 3, characterized in that the component (1) has as body a closed or open hollow profile, which has a between the first and second end (E1, E2) extending interior, wherein the first end (E1) and the second end (E2) are connectable to the first and the second impact element, respectively, and wherein the body has an outer and an inner cross section (11, 11 ^' ) and the first surface (8) facing away from the interior and the second surface (9) facing the interior.

Component (1) according to claim 5, characterized in that the inner and / or the outer cross section (1 1, 1 1 ^' ) has a circular, elliptical, square or rectangular contour or a polygonal contour.

Component according to claim 5 or 6, characterized in that the in and / or the outer cross section (1 1, 1 1 ^' ) along the extension in

Longitudinal direction (L) is constant.

Component according to one or more of claims 5 to 6, characterized

in that the inner and / or the outer cross-section (11, 11 ^' ) in a region between the first and the second end (E1, E2) from the first to the second end (E1, E2) of the composite component (1 ) increases.

Component (1) according to one or more of claims 1 to 8, characterized in that the wall thickness (10, 10 ^' ) in a region between the first and the second end (E1, E2) from the first to the second end (E1, E2 ) of the component (1) increases. 10. component (1) according to one or more of claims 1 to 9, characterized

characterized in that the polymer matrix constituting the bundles Embedding carbon fibers and / or the matrix system is a thermosetting resin.

1 1. Component (1) according to one or more of claims 1 to 10, characterized

characterized in that the component (1) has at its first end (E1) a region for introducing the impact energy.

12. Component (1) according to one or more of claims 1 to 1 1, characterized

in that the component (1) is constructed from two partial bodies, which are connected to each other in the longitudinal direction (L) to form the component (1).

13. The component (1) according to claim 12, characterized in that the part bodies laterally in the longitudinal extension flanges (6), via which the

Part bodies are interconnected.

14. Component (1) according to one or more of claims 1 to 13, characterized

in that the wall on the first and / or second surface (8, 9) has reinforcing elements (2) extending in the direction of

Lengthwise (L) of the component (1) extend.

15. component (1) one or more of claims 1 to 14, characterized

characterized in that the wall additionally comprises at least one layer of unidirectionally oriented long fibers, the at least one layer being arranged on at least one of the surfaces (8, 9) or in the interior of the wall and extending between the first and second ends (E1, E2 ) of the component (1).

16. Component (1) according to one or more of claims 1 to 15, characterized

characterized in that the fiber volume fraction of the carbon fibers in the wall is in the range of 45% by volume to 65% by volume.

17. Component (1) according to one or more of claims 1 to 16, characterized in that the carbon fibers have a length in the range of 5 mm and 70 mm.