DE102022131766A1 - Method and computer program for generating manufacturing data and method for manufacturing - Google Patents

Abstract

The invention relates to a method for generating production data for producing a fiber composite component from a fiber composite material comprising a fiber material and a matrix material embedding the fiber material, the method comprising the following steps: - providing a digital construction space as an image of a physical construction space that has been created or is to be created and in which the fiber composite component to be produced is to be used for its intended use, - wherein the digital construction space has at least two load points spaced apart from one another at which the fiber composite component to be produced is to be arranged in the physical construction space, - calculating a load path within the digital construction space between the at least two load points as a function of a force acting on at least one of the load points by means of a digital data processing system, - adding at least one band-shaped or strand-shaped fiber element to the digital construction space as a function of the calculated load path in such a way that the fiber element extends without interruption between the two load points along the load profile and the fiber orientation of the fiber element corresponds to the previously calculated load profile, by means of the digital data processing system, - calculating a load on the the structure formed from the band-shaped or strand-shaped fiber elements contained in the digital construction space as a function of a verification force acting on at least one of the load points, by means of the digital data processing system,- repeating the steps of adding the fiber elements and calculating the load until the calculated load is acceptable, and- generating manufacturing data as a function of the band-shaped or strand-shaped fiber elements of the structure in the digital construction space.

Description

The invention relates to a method for generating manufacturing data for producing a fiber composite component from a fiber composite material comprising a fiber material and a matrix material embedding the fiber material. The invention also relates to a computer program for this purpose.

The invention also relates to a manufacturing method for producing a fiber composite component from a fiber composite material comprising a fiber material and a matrix material embedding the fiber material.

Due to their special property of being highly rigid and strong at a low weight, fiber composite components can now be found in almost all areas. Complex fiber composite components are also used in load-bearing structures, particularly where low weight is important, such as in the automotive or aircraft industries. However, the manufacturing costs are higher than with other, conventional materials, particularly for complex component shapes, because fiber composite materials are not suitable for conventional manufacturing processes using isotropic materials.

A fiber composite component is manufactured by introducing a fiber material (dry or pre-impregnated fiber semi-finished product) into a molding tool that has the shape of the desired component or at least corresponds to it. If the fiber material is not yet or not sufficiently impregnated with matrix material, the matrix material is then infused into the deposited fiber semi-finished products. The matrix material is then cured to produce the fiber composite component.

Another difference to conventional, particularly isotropic materials (such as iron, steel or aluminum) is that fiber composite materials exhibit direction-dependent material behavior (anisotropic material behavior), which is characterized in particular by the fiber direction of the semi-finished fiber on which the fiber composite component is based. Fiber composite components generally have their greatest stability and strength along their fiber direction, while the stability of the fiber composite component is relatively weak orthogonal to the fiber plane. Not least for this reason, fiber composite components are usually formed in a flat form in order to take advantage of the direction-dependent material behavior.

Even if the weight/stiffness ratio of fiber composite components is particularly favorable compared to conventional materials, there are still efforts to optimize the later component shape of a fiber composite component with regard to certain optimization criteria. Such optimization criteria can be, for example, reducing the weight, reducing the materials used or similar. The prerequisite for this, however, is always that the optimized component shape is selected in such a way that a later fiber composite component based on it meets the specified boundary conditions, such as clamping, force, bearing point, load and load direction. First and foremost, the later fiber composite component must meet the requirements of the respective area of application and purpose. The optimization of the component shape is also called topology optimization.

There are topology optimizers for isotropic materials, i.e. materials that have the same material properties in all directions, which find the optimal component shape in any three-dimensional design space. It is known that the entire construction space is initially filled with the material so that a maximum component is formed that fills the entire construction space. Then, to reduce the density within the component, individual elements that are not involved in load transfer are removed. The component is thinned out, so to speak.

However, such topology optimization is unsuitable for fiber composite components and the fiber composite materials used. With fiber composite components, individual elements cannot simply be removed because the fiber composite component is usually manufactured using quasi-endless fiber strands or fiber tapes in which the reinforcing fibers must not be severed in the direction of the load. Removing individual elements from the component without taking into account the reinforcing fibers, which play a key role in load transfer, would create the risk that the component could either not be manufactured or would not meet the desired requirements.

The special challenge of fiber composites can be met by defining appropriate constraints for fiber angle and manufacturability. However, there is then a risk that the optimal component shape, especially a component shape with a maximally reduced weight, will not be found, and it is not guaranteed that a design suitable for fiber composites will be created.

In addition, taking manufacturing constraints into account is not trivial and it is not clear that adjustments will be necessary depending on the manufacturing process. These adjustments lead to deviations from the design, which requires a new design step. As a result, the criteria from the primary design are no longer met.

From the EN 10 2011 056 677 A1 An optimization method is known that takes into account the problems of topology optimization of fiber composite materials. The component shape is changed within the predefined abdominal cavity in such a way that the optimization criteria are approximated, whereby the fiber path of the changed component shape is then adapted depending on specified boundary conditions.

However, with these topology optimizations there is always the problem that the optimal component shape has to be found by removing material.

It is therefore an object of the present invention to provide an improved method for generating manufacturing data for the production of a fiber composite component which has an optimized component shape.

The object is achieved according to the invention with the method according to claim 1, the computer program according to claim 6 and the method for producing a fiber composite component according to claim 7. Advantageous embodiments of the invention can be found in the corresponding subclaims.

• - Bereitstellen eines digitalen Bauraums als Abbild eines erstellten oder zu erstellenden physischen Bauraums, in den das herzustellende Faserverbundbauteil für den bestimmungsgemäßen Gebrauch eingesetzt werden soll,
• - wobei der digitale Bauraum mindestens zwei voneinander beabstandete Lastpunkte hat, an denen das herzustellende Faserverbundbauteil in dem physischen Bauraum angeordnet werden soll,
• - Berechnen eines Lastpfades innerhalb des digitalen Bauraumes zwischen den mindestens zwei Lastpunkten in Abhängigkeit von einer auf mindestens einen der Lastpunkte wirkenden Kraft mittels einer digitalen Datenverarbeitungsanlage,
• - Hinzufügen mindestens eines bandförmigen oder strangförmigen Faserelementes in den digitalen Bauraum in Abhängigkeit von dem berechneten Lastpfad derart, dass sich das Faserelement ohne Unterbrechung zwischen den beiden Lastpunkten entlang des Lastverlaufes erstreckt und die Faserorientierung des Faserelementes dem zuvor berechneten Lastverlauf entspricht, mittels der digitalen Datenverarbeitungsanlage,
• - Berechnen einer Belastung auf die durch die in dem digitalen Bauraum enthaltenen bandförmigen oder strangförmigen Faserelemente gebildeten Struktur in Abhängigkeit von einer auf mindestens einen der Lastpunkte wirkenden Überprüfungskraft, mittels der digitalen Datenverarbeitungsanlage,
• - Wiederholen der Schritte des Hinzufügens der Faserelemente und der Berechnung der Belastung solange, bis die berechnete Belastung akzeptabel ist, und
• - Erzeugen von Fertigungsdaten in Abhängigkeit von den bandförmigen oder strangförmigen Faserelementen der Struktur in dem digitalen Bauraum.

According to claim 1, a method for generating manufacturing data for producing a fiber composite component from a fiber composite material comprising a fiber material and a matrix material embedding the fiber material, the method comprising the following steps:

• - Providing a digital construction space as an image of a physical construction space created or to be created, in which the fiber composite component to be manufactured is to be used for its intended use,
• - wherein the digital construction space has at least two spaced-apart load points at which the fiber composite component to be manufactured is to be arranged in the physical construction space,
• - Calculating a load path within the digital installation space between the at least two load points as a function of a force acting on at least one of the load points by means of a digital data processing system,
• - Adding at least one ribbon-shaped or strand-shaped fibre element into the digital construction space depending on the calculated load path such that the fibre element extends without interruption between the two load points along the load profile and the fibre orientation of the fibre element corresponds to the previously calculated load profile, by means of the digital data processing system,
• - Calculating a load on the structure formed by the band-shaped or strand-shaped fibre elements contained in the digital construction space as a function of a verification force acting on at least one of the load points, by means of the digital data processing system,
• - Repeat the steps of adding the fibre elements and calculating the load until the calculated load is acceptable, and
• - Generation of manufacturing data depending on the band-shaped or strand-shaped fiber elements of the structure in the digital construction space.

A digital data processing system is first provided with a digital installation space and corresponding boundary conditions for optimization. The boundary conditions are in particular at least two load points at which the fiber composite component is to be attached or arranged in the installation space. These load points are arranged in particular at the edge of the installation space. A digital installation space is understood to be a virtual installation space that is an image of a physical installation space that already exists or that is still to be created.

This installation space can be empty at the beginning. Before the optimization begins, it does not have any structure that could resemble a corresponding component for load transfer. A load path is now calculated by applying a force to at least one load point, which is then transferred to the other load point. The force flow from the first load point on which the force acts to the second load point, via which the force is transferred, is now calculated using the digital data processing system. The force flow or load path leads through the digital installation space. It is also conceivable, however, that the installation space is initially occupied with a soft starting structure before the optimization begins, from which the optimization is then carried out.

For this purpose, it can be assumed, for example, that the installation space is filled with a soft, isotopic material in order to be able to calculate the load path or the force flow through the installation space without any load-bearing structure.

After the load path has been calculated, the first fiber elements are added to the digital installation space. These fiber elements are band-shaped or strand-shaped and are introduced along the calculated load path. The band-shaped or strand-shaped fiber elements extend continuously from the first load point to at least the second load point, so that the fiber orientation is oriented towards the load path and in particular has no interruptions. As a result, the fiber elements are always introduced into the installation space as a whole, so that optimal load transfer along the load path is achieved.

The fiber orientation does not necessarily have to correspond to the orientation of the load path at every point along the fiber element. A deviation can be provided within certain tolerances, simulating a type of artificial growth.

The structure to be created is thus created a kind of artificial growth along the load path, whereby the artificial growth can be achieved, among other things, by simulating virtual work, an energy-based approach or directly along the maximum load flow.

A load on the structure in the digital build space formed by the strand-like or ribbon-like fiber elements is then calculated by applying a verification force to at least one of the load points. This verification force acts on the formed structure and leads to loads within the structure that can be calculated. Such loads can be, for example, strain loads, stress loads and/or torsional loads.

Depending on the calculated load on the structure when the test force is applied, it is now determined whether the structure thus formed can withstand the load within limits and is therefore acceptable. If, on the other hand, the load is not acceptable, i.e. the load acting on the structure is too great so that failure of the structure is possible, the previous steps are repeated until the load acting on the structure is acceptable.

The manufacturing data can then be generated from this in order to physically produce the fiber composite component.

The advantage of the present invention is that the basic properties of fiber composite materials are taken into account in the topology optimization by not optimizing a structure by removing elements, but by generating a structure in the form of artificial growth. This creates an optimized component that can always be manufactured and is created accordingly to suit the fiber.

According to one embodiment, it is provided that at least one band-shaped or strand-shaped fiber element is added, which extends from one of the load points along the load curve and ends within the digital installation space in front of the other load point.

After the first iteration step, it is conceivable that band-shaped or strand-shaped fiber elements are also added, which do not extend completely from the first load point to the second load point, but end within the construction space and are thus also cut there during physical production.

According to one embodiment, it is provided that at least one band-shaped or strand-shaped fiber element is added, which runs from a load point through the installation space and ends at the same load point.

This has the advantage that such a fiber element does not have to be cut within the installation space when the component is actually to be manufactured, which is particularly advantageous from a manufacturing point of view.

According to one embodiment, it is provided that, depending on the calculated load, fiber elements already added are removed from the structure formed by the band-shaped or strand-shaped fiber elements contained in the digital construction space.

The structure created within the installation space can change the flow of forces, which makes it conceivable that fiber elements that have already been added are no longer involved in load transfer. It is therefore conceivable that fiber elements that have already been added are removed again when they are no longer involved in load transfer or are no longer involved to a significant extent.

According to one embodiment, it is provided that before repeating the steps of the By adding the fiber elements and calculating the load, a new load path is calculated taking into account the structure already formed by the band-shaped or strand-shaped fiber elements contained in the digital construction space.

According to one embodiment, the addition of fiber elements along the load path is based on a simulation of tree growth or a river course.

• - Erzeugen von Fertigungsdaten gemäß vorstehend beschriebenen Verfahren,
• - Herstellen des Faserverbundbauteils unter Verwendung der erzeugten Fertigungsdaten.

The object is also achieved with the manufacturing method of the type mentioned at the beginning for producing a fiber composite component from a fiber composite material comprising a fiber material and a matrix material embedding the fiber material with the following steps:

• - Generating manufacturing data according to the procedures described above,
• - Manufacturing the fiber composite component using the generated manufacturing data.

• 1 Darstellung eines virtuellen Bauraum mit virtuellem Bauteil;
• 2 Faserdetaildarstellung des virtuellen Bauteils.

The invention is explained in more detail with reference to the attached figures. They show:

• 1 Representation of a virtual installation space with a virtual component;
• 2 Fiber detail representation of the virtual component.

1 shows the virtual construction space 10, which is an image of an existing or yet to be created physical construction space. On the left side there is a first load point 11, which serves as an anchor point for load transfer. On the upper right side there is a second load point 12, which represents a load introduction point. A force K is exerted on the fiber composite component 13 to be produced via this load introduction point 12, which is then to be transferred via the first load point 11.

1 shows the generic result of a possible grown fiber composite structure 13. The construction space 10 is shown as a large rectangle of the available construction space. On the left side, a fixed residual stress is specified, which is intended to absorb the force K to be absorbed at the load introduction point 12. With the help of a very soft starting structure that fills the construction space 10, the load curve can be generated with the help of which the fiber composite structure 13 can grow. However, it is also conceivable that the construction space 10 is initially empty and a soft starting structure is automatically generated first.

In order to be able to depict the growth, a direction, a length and/or a thickness of the fiber elements is specified in each iteration step. As a rule, a fiber element has a fixed thickness perpendicular to the growth direction and a limited length. With each iteration step, a fiber element is added, starting from a specified load point. A digital data processing system is then used to decide whether the current strand should continue to grow or not. In the first case, the step of attaching elements is repeated and in the other case a new strand is started from a new or the same load point. When the current fiber strand has reached the edge of the virtual construction space, a new strand is started. If all design conditions are met, the process ends.

The method presented is intended to be used to generate structures suitable for fiber composites. Ideally, the final fiber or roving deposition path is already created in this process. This means that the generative process ensures that the component is created according to a possible roving deposition (according to the boundary conditions).

One possible area of application is fiber deposition heads, tape layers or 3D printers with fiber reinforcements. These machines have the "challenge" that the start of the deposition is not trivial. The fibers must be clamped or held on the deposition tool outside the construction space and can then be deposited. The fibers are usually pulled out of the head. For this, conditions must be specified in the design process so that the fibers run from the load introduction point to the load discharge point.

A maximum of one cutting of the fibers is permitted. A new start in the middle of the component is generally not possible. The 2 visualizes this procedure again, using the same boundary conditions as in 1 apply.

In this process, band-shaped or strand-shaped fiber elements 14 are added along the calculated force flow or load path, which extend from the load introduction point 12 in the direction of the suspension 11 (first load point). These fiber elements 14 run continuously between the two points 11 and 12, so that a continuous fiber-correct course is provided. These fiber elements 14 start outside the installation space and only stop again behind it.

An exception to these fiber elements 14 are the short fiber elements 15, which may be cut once within the installation space, so that these fiber elements 15 are behind the first Start at load point 11 and end within the installation space.

The fiber element 16 has a special shape because it is continuous and starts and ends at the first load point 11 and runs through the installation space in between.

It is conceivable that in a first iteration step the continuous fiber elements 14 are first added along the force flow within the abdominal cavity, whereby the structure thus formed is then analyzed with regard to its load by means of a test force.

The loading may reveal that stresses exist between the upper and lower continuous fiber elements 14, so the fiber element 16 was added, which starts at the first load point and ends there again.

A further load test may then reveal the need for a thickening above and below the structure at the first load point 11, so that the shortened fiber elements 15 are added. Due to the load test, however, it is only necessary to provide this area of the first load point 11 and not to let it run continuously.

List of reference symbols

10

Installation space

11

first load point

12

second load point

13

Fiber composite component

14

Fibre elements

15

short fiber elements

16

Fiber element

K

Power

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was 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 accepts no liability for any errors or omissions.

Cited patent literature

• DE 102011056677 A1 [0011]

Claims (8)

Method for generating production data for producing a fiber composite component (13) from a fiber composite material comprising a fiber material and a matrix material embedding the fiber material, the method comprising the following steps: - providing a digital construction space (10) as an image of a physical construction space (10) created or to be created, in which the fiber composite component (13) to be produced is to be used for the intended use, - wherein the digital construction space (10) has at least two load points (11, 12) spaced apart from one another, at which the fiber composite component (13) to be produced is to be arranged in the physical construction space (10), - calculating a load path within the digital construction space (10) between the at least two load points (11, 12) as a function of a force (K) acting on at least one of the load points (11, 12) by means of a digital data processing system, - adding at least one band-shaped or strand-shaped fiber element (14, 15, 16) into the digital construction space (10) depending on the calculated load path such that the fiber element (14, 15, 16) extends without interruption between the two load points (11, 12) along the load profile and the fiber orientation of the fiber element (14, 15, 16) corresponds to the previously calculated load profile, by means of the digital data processing system, - calculating a load on the structure formed by the band-shaped or strand-shaped fiber elements (14, 15, 16) contained in the digital construction space (10) depending on a checking force acting on at least one of the load points (11, 12), by means of the digital data processing system, - repeating the steps of adding the fiber elements (14, 15, 16) and calculating the load until the calculated load is acceptable, and - generating production data depending on the band-shaped or strand-shaped fiber elements (14, 15, 16) of the Structure in the digital construction space (10). Procedure according to Claim 1 , characterized in that at least one band-shaped or strand-shaped fiber element (14, 15, 16) is added, which extends from one of the load points (11, 12) along the load profile and ends within the digital construction space (10) in front of the other load point (11, 12). Procedure according to Claim 1 or 2 , characterized in that at least one band-shaped or strand-shaped fiber element (14, 15, 16) is added, which runs from a load point (11, 12) through the construction space (10) and ends at the same load point (11, 12). Method according to one of the preceding claims, characterized in that, depending on the calculated load, fiber elements (14, 15, 16) already added are removed from the structure formed by the band-shaped or strand-shaped fiber elements (14, 15, 16) contained in the digital construction space (10). Method according to one of the preceding claims, characterized in that before repeating the steps of adding the fiber elements (14, 15, 16) and calculating the load, a new load path is calculated taking into account the structure already formed by the band-shaped or strand-shaped fiber elements (14, 15, 16) contained in the digital construction space (10). Method according to one of the preceding claims, characterized in that the addition of fiber elements (14, 15, 16) along the load path is based on a simulation of tree growth or a river course. Computer program with program code means configured to carry out the method according to one of the preceding claims when the computer program is executed on a digital data processing system. Manufacturing method for producing a fiber composite component (13) from a fiber composite material comprising a fiber material and a matrix material embedding the fiber material, comprising the steps of: - generating manufacturing data according to the method according to one of the Claims 1 until 7 , - producing the fiber composite component (13) using the generated manufacturing data.