WO2023170029A1

WO2023170029A1 - Method for producing an at least two-layered sandwich component

Info

Publication number: WO2023170029A1
Application number: PCT/EP2023/055678
Authority: WO
Inventors: Julian Gregor KUNTZ
Original assignee: PFW Aerospace GmbH
Priority date: 2022-03-10
Filing date: 2023-03-07
Publication date: 2023-09-14
Also published as: DE102022105673A1

Abstract

The invention relates to a method for producing an at least two-layered sandwich component (50) in the form of a tube (24) or in the form of a panel (26), wherein the sandwich component (50) is exposed to a cold side (20) and to a hot side (22), comprising at least the following method steps: producing an insulation layer (54) which is made of a gas-tight, high-temperature-resistant glass foam material (10) and faces the hot side (22), and producing an outer layer (52) of the sandwich component (50), which outer layer comprises a fiber-reinforced composite material (12) and faces the cold side (20). The invention also relates to a sandwich component (50) of this type and to the use thereof in an aircraft.

Description

Method for producing an at least two-layer sandwich component

Technical area

The invention relates to a method for producing an at least two-layer sandwich component in the form of a tube or in the form of a plate, the sandwich component being exposed to a cold side and a hot side. The sandwich component according to the invention can be used as a hot gas line, as an exhaust line, as a silencer or as a fire protection wall in an aircraft, for example in an airplane, a land vehicle, a water vehicle or a space vehicle.

State of the art

DE 10 2016 000 915 A1 relates to a foundation structure of a building. The structure includes load-bearing insulation, with the insulation being provided as foam glass gravel as a base for a strip foundation. The strip foundation is completely surrounded by a foam glass gravel layer, except where there are load-bearing walls or supports. This avoids thermal bridges in the parts of the floor slab facing the outer wall, which prevents mold and moisture in the outer corners of a building.

DE 11 2011 102 404 T5 relates to foam glass with low coefficients of thermal expansion and associated processes. Foam glass can contain natural glass, whereby the foam glass contains more than 5% aluminum oxide, based on the weight of the foam glass, and has a coefficient of thermal expansion Range between 4Dx 10' ⁶ ppm/°C and 6 x 10' ⁶ ppm/°C. A composition for producing the foam glass may include natural glass containing at least 5% aluminum oxide by weight of the composition, sodium carbonate containing less than 10% by weight of the composition, and boric acid containing at least 5% based on the weight of the composition. A method of making foam glass may include mixing natural glass with boron to form a mixture, grinding and melting the mixture at a temperature of at least 900 °C, and allowing the molten mixture to cool so that the foam glass contains at least 5% alumina , based on the weight of the foam glass, and at least 5% boron oxide, based on the weight of the foam glass.

AT 521 214 B1 refers to the shaping of glass foam into semi-finished products with fiber composites. A fiber composite semi-finished product is proposed, having a lower and an upper cover layer with fibers, the lower cover layer being arranged parallel to the upper cover layer. Between the lower and upper cover layers, ellipsoidal glass foam elements are arranged in at least two parallel planes, with the glass foam elements being arranged in a Cartesian grid in each plane and the grid points of two adjacent parallel planes being offset from one another in the direction of the planes in such a way that the Cartesian grid points in the one of the two adjacent levels, are arranged between the Cartesian grid points in the other of the two adjacent levels, with fibers and binding material being arranged between the ellipsoidal glass foam elements. The ellipsoid-shaped elements are manufactured separately as finished glass foam elements and glued to cover layers using a different material. The glass foam elements have ribs on their surfaces, the ribs of the glass foam elements interlocking with ribs of glass foam elements arranged in adjacent levels.

DE 103 41 158 A1 relates to a component containing glass foam for sound dampening and sound insulation. The component containing glass foam for sound dampening and/or sound insulation is connected to a protective material at least on parts of the component. The glass foam component preferably has a first side, a second side and an edge connecting the first and second sides. The protective material preferably closes at least on parts of the edge and on an area near the edge of the first and second sides of the Glass foam component. Furthermore, stand walls, silencer backdrops and gas-carrying channels are disclosed, which are equipped with glass foam components for sound insulation and/or sound insulation.

Previous concepts for insulated hot gas pipes are generally constructed in such a way that there is a gas-tight metal pipe on the hot inside, which is usually surrounded by insulating material, whereby the insulating material is generally not airtight and usually not dimensionally stable, such as insulating wool. In plant construction, but not in aircraft construction, there are pipe half-shells made of foam glass, which are applied to the outside of an airtight metal pipe as external insulation, whereby the joint between the two half-shells is glued, does not need to be airtight and does not absorb any internal pressure, as this only comes from the Inner tube is worn.

In aircraft construction, such inner tubes for hot gas are currently often made of titanium in order to meet the weight, temperature and corrosion requirements and are therefore relatively expensive. Alternatively, such tubes are made of steel alloys, which, however, entails significant weight disadvantages in aircraft construction.

An alternative to save costs and weight is to manufacture such hot gas pipes from fiber composite materials, although the high temperatures and the creation of an airtight envelope represent a challenge. Sandwich constructions are also known in which a foam material is framed by cover layers made of metal or fiber composite material.

Presentation of the invention

The invention is based on the object, particularly in aviation applications, of providing a line or plate arrangement which is very economical in terms of weight and creates an airtight insulating layer, while at the same time ensuring resistance to high temperatures.

According to the invention, a method for producing an at least two-layer sandwich component is proposed, which is manufactured in the form of a tube or in the form of a plate, the sandwich component having a cold side and is exposed to a hot side, and at least the following process steps are carried out: a) production of an insulation layer facing the hot side, which contains a gas-tight, high-temperature-resistant glass foam material and b) production of an outer layer of the sandwich component facing the cold side, which comprises a fiber composite material.

The method proposed according to the invention makes it possible to produce sandwich components that can withstand high and extremely high temperatures, while at the same time, by using a fiber composite material, inexpensive materials can be used that also have an extremely low weight, which is very advantageous for aviation applications.

In an advantageous embodiment of the method proposed according to the invention, the insulation layer facing the hot side can be provided with a layer which contains a fiber composite material with a ceramic, glass ceramic or glass matrix material. This optional additional layer on the insulation layer facing the hot side makes it possible to achieve a further increase in temperature resistance as well as an improved mechanical resistance of the surface on the hot gas side.

Advantageously, the insulation layer facing the hot side according to method step a), which consists of a gas-tight, high-temperature-resistant glass foam material, is manufactured from a block material or with the aid of a preform which comprises at least one glass granulate and a foaming agent.

In the method proposed according to the invention, the insulation layer facing the hot side is smoothed by locally generating high temperatures. This allows, for example, broken glass pores to be smoothed at locally high temperatures, resulting in an extremely smooth, fluidically favorable inside of the insulation layer. The resulting closure of the glass foam surface also prevents water from penetrating into pores and thus preventing damage in the event of frost. In a further advantageous embodiment of the method proposed according to the invention, the sandwich component is held in a closed mold during the implementation of method steps a) and b), in which the glass granules are melted and then foamed under the action of the foaming agent.

In a further advantageous embodiment of the method proposed according to the invention, the fiber material from which the cover layer or the cover layers are formed is impregnated with the melt of the glass granules as a preform in the form of a fiber molding or a porous fiber-ceramic material in the closed mold.

In a further advantageous embodiment of the method proposed according to the invention, the gas-tight, high-temperature-resistant glass foam material is mixed with fiber material, in particular carbon, metal, basalt or ceramic fiber material or particularly high-temperature-resistant glass fiber material during its production, the fiber material being present both as a short fiber and as a long fiber can.

In a further embodiment of the method proposed according to the invention, the fiber material - present as a short or long fiber or as a continuous fiber - is introduced into or around the glass granulate before it is melted or foamed or as a wound preform for later cover layers or as a semi-finished textile product, in particular as a braided fabric cover layer on a or several surfaces, or introduced as a spacer fabric, which are soaked by the glass granules during the melting and foaming process. In a further embodiment, a glass material that achieves a particularly low viscosity at the process temperature, for example a glass solder, is used to impregnate the fiber gaps with the glass matrix. In particular, this glass material with a particularly low viscosity is only used in the areas of the particularly densely packed fiber cover layers (hot and / or cold side) and in the area of the glass foam another glass material, which may also have a higher melting temperature.

In a further embodiment of the method according to the invention, the fibers (e.g. rovings) used for depositing the cover layers are already in production of the preform, for example wound, is pre-impregnated with a glass material or a glass solder, for example in the form of a prepreg tape, which was impregnated in a previous process.

In an advantageous embodiment of the method proposed according to the invention, air channels are introduced on an outside of the insulation layer, which contains the gas-tight, high-temperature-resistant glass foam material, which remain air-permeable after the outer layer has been laminated on and, in the event of a leak in the insulation layer, guide air escaping through this to discrete air outlet openings assigned to the temperature sensors. Preparatory measures for a leak detection system can be taken during the production of the sandwich component.

In a further advantageous embodiment of the method proposed according to the invention, fiber-optic temperature sensors are laminated into the outer layer made of fiber material covering the insulation layer. This also means that, in an alternative approach, precautions can be taken for a later leak detection device.

In a further advantageous embodiment of the method proposed according to the invention, during the heat treatment of the insulation layer facing the hot side, webs of broken glass bubbles of the glass granules are melted, which contract due to surface tension to form a smooth surface, so that the inside of the insulation layer facing the hot air flow, for example, can be effectively smoothed and a low-friction flow occurs.

In the method proposed according to the invention, the heat treatment is also carried out on the end faces of the sandwich component, in the event that this is manufactured as a tube, in order to obtain smooth surfaces for sealing a joint of two sandwich components proposed according to the invention to be connected to one another, designed as tubes.

Advantageously, the fiber composite material with a ceramic matrix is laminated onto the insulation layer facing the hot side, and then a temperature treatment of the laminate and the insulation layer is carried out for joint curing or pyrolysis of the ceramic matrix. This allows achieve a common production step. Furthermore, the combination of fiber composite material with a ceramic matrix and the insulation layer is extremely effective.

In a further embodiment of the method proposed according to the invention, a prefabricated layer of the fiber material with a ceramic, glass-ceramic or glass-like inorganic matrix can be applied to the hot side facing the hot side by means of a soldering process, for example using a glass solder (i.e. a glass with a lower melting temperature than that of the foam glass). , gas-tight, high-temperature-resistant insulation layer can be soldered on. If necessary, this soldering process can also be carried out on both sides, i.e. H. be applied on the hot side and on the cold side, for example if both can take place at the same time in a temperature treatment process.

In a further embodiment of the method proposed according to the invention, a prefabricated layer of the fiber composite material with a ceramic matrix can be glued to the gas-tight, high-temperature-resistant insulation layer facing the hot side by means of an adhesive process using a high-temperature-resistant adhesive. With this procedure, the high-temperature treatment between the fiber composite material with a ceramic matrix on the one hand and the insulation layer can be saved.

In an advantageous embodiment of the method proposed according to the invention, the fiber composite material is applied to the cold side as an outer layer using thermoset prepreg-based processes, resin infusion processes, RTM processes or thermoplastic prepreg-based processes, in particular TP-AFP processes.

In addition, the invention relates to a sandwich component in the form of a tube or a plate, which is exposed to a cold side and a hot side, the sandwich component being designed in at least two layers and comprising an insulation layer facing the hot side, which comprises a gas-tight, high-temperature-resistant glass foam material and a outer layer facing the cold side, which contains a fiber composite material. The sandwich component proposed according to the invention has, on the one hand, a very low weight, which is extremely advantageous for aviation applications, and, on the other hand, is characterized by the fact that there is an airtight insulation layer, namely the insulation layer made of the glass foam material, which at the same time can withstand high temperatures.

The sandwich component can be designed both in the form of a tube and in the form of a plate, for example as a panel.

A further advantageous embodiment variant of the sandwich component proposed according to the invention provides that the insulation layer facing the hot side, which comprises a gas-tight, high-temperature-resistant glass foam material, is provided with a layer which contains a fiber composite material with a ceramic, glass ceramic or glass matrix material. This makes it possible to provide a three-layer sandwich component that goes beyond a two-layer sandwich component and is further improved in terms of its temperature resistance and mechanical strength and its tightness requirements.

Furthermore, the invention relates to the use of the sandwich component in an aircraft, in particular in an airplane, as a hot gas line, bleed air or exhaust line or as an engine or APU silencer. Another use of the sandwich component proposed according to the invention is its use as an enclosure for units that either become hot during operation and/or can potentially become hot in the event of an error/failure or in the event of fire, in particular a solid oxide fuel cell or batteries or low-temperature energy converters or other waste heat. producing components of an aircraft, in particular an aircraft. Furthermore, the sandwich component can be used as a fire protection barrier or the like in a land vehicle, water vehicle or even in a space vehicle.

Advantages of the invention

Due to the solution proposed according to the invention of a sandwich component, in particular manufactured according to the method proposed according to the invention, this comprises a jacket made of high-strength fiber composite material and a Insulating layer made of a gas-tight, high-temperature-resistant glass foam material. The invention provides functionality for a sandwich component in that, on the one hand, it comprises an airtight insulation layer, which, on the other hand, withstands high temperatures. Previously, it was necessary, for example in the case of bleed air pipes in aircraft, to ensure airtightness through other layers or components, since the available, high-temperature-resistant insulation materials are insufficiently airtight.

The solution proposed according to the invention enables the use of foams also for high temperatures, but now with glass instead of polymer materials as the foam material. At the same time, the solution proposed according to the invention can be used to achieve constructions with a high thermal insulation effect, which, in contrast to often used soft mineral or glass wool mats, have increased dimensional stability and can therefore be structurally connected to structural components in an easier way.

The solution proposed according to the invention can further improve the roughness of mechanically processed surfaces of the glass foam material, since the number of open glass foam material pores on the surface, in particular on the inside of the insulation layer, is significantly reduced and thus the durability of this surface is improved. Furthermore, by smoothing the inside of the insulation layer, the flow resistance for media is reduced and at the same time the probability of detachment of surface particles of the insulation layer is reduced.

The solution proposed according to the invention makes it possible to provide a sandwich component, which in particular represents a hot gas line, for example a bleed air or exhaust line or an engine or APU silencer in an aircraft, in particular in an airplane, the proposed sandwich component comprising an outer jacket a fiber composite material and comprises an internal insulation layer made of a gas-tight, high-temperature-resistant glass foam material, such as foam glass. Optionally, the inside of the insulation layer can be coated with another high-temperature-resistant material, in particular a fiber composite material with ceramic, glass-ceramic or glass-like, inorganic Matrix must be covered. The sandwich component proposed according to the invention can be in the form of a tube or, when opened, as a flat panel, which serves, for example, as a heat or fire protection wall.

With the solution proposed according to the invention, a previously necessary additional outer shell for leak detection in bleed air lines can either be reduced to a thin film shell without further insulation or can be eliminated entirely by introducing air channels on the outer layer of the insulation layer, which lead to discrete, defined air outlet points of the pipe-shaped manufactured sandwich component, which in turn has temperature sensors on it. Alternatively, these temperature sensors can also be laminated into the sandwich component in the form of films, fibers or wires.

As a result of the solution proposed according to the invention, for example, in the case of a sandwich component according to the invention in the form of a tube, the outer layer made of fiber composite material can absorb the tensile load that can arise, for example, from internal pressure in the tube and not the inner tube as in previous applications. The gas-tight, high-temperature-resistant foam glass material, on the other hand, takes on, in addition to the insulation function, the task of ensuring the tightness of the tubular sandwich component, so that the outer layer made of fiber composite material does not have to take on this task. This can advantageously be achieved for the outer shell, i.e. H. the outer layer can be used materials that have a lower temperature resistance than would be the case for an inner shell in contact with the hot gas. Since a significantly larger selection of fiber composite materials is available, materials with better mechanical properties and/or lower prices or processing costs can also be used. The foam glass material used as an insulation layer, on the other hand, has the advantage that it hardly emits gases and therefore the hot medium is not contaminated with vapors.

To increase the strength of the insulation layer, fiber material in the form of carbon, metal (for example steel or nickel-based superalloy), basalt, ceramic fibers or particularly high-temperature-resistant glass fibers can be introduced during the production of the glass granules and / or the glass foam material in order to increase the strength and Damage tolerance of this material increase. The fiber material, available as short, long or so-called continuous fibers, serves as a stiffener and crack stopper in the glass foam material. The fiber material can be mixed into the glass granulate before it is melted or foamed or can be inserted as a wound preform (for later cover layers) or semi-finished textile product, in particular as a braid or fabric cover layer or spacer fabric. These fiber materials can then be bound and soaked in the glass granules during the melting and foaming process. In order to make it easier to impregnate the fiber gaps with the glass matrix, a glass material can optionally be used that achieves a particularly low viscosity at the process temperature, for example a glass solder. Furthermore, this glass material with a particularly low viscosity can only be used in the areas of the fiber cover layers (hot and / or cold side) and in the area of the glass foam another glass material, which may also have a higher melting temperature.

In the event of impact stress on the sandwich component element according to the invention from the outside, in particular on the outer layer made of fiber composite material, this must be designed with regard to its residual mechanical strength. However, the risk that the sandwich component according to the invention, which is manufactured in the form of a tube, will become leaky even with low stress is low, since the insulation layer made of foam material is located underneath it. Since this comprises many individual cells, each of which is gas-tight, gas-tightness can still be expected even if some of the outer cells were damaged. This creates an additional safety gain, as small impact loads are often below the visible range and are therefore not detected, but the design is tolerant of these small damages.

By introducing air channels on the outside of the insulation layer, preparatory work for a leak detection device can be carried out. If the further manufacturing steps ensure that the air channels remain permeable to air even after the outer layer made of fiber composite material has been laminated on, in the event of a leak in the inner layer, ie the insulation layer, they direct air escaping to discrete air outlet points located in the outer layer, in front of which temperature sensors are placed . This means that an additional, non-structural air ducting envelope can be saved. Alternatively, a leak detection device can be provided by laminating fiber optic sensors into the outer layer made of fiber composite material. If, in the event of a leak in the insulation layer and air flowing out as a result, this causes a local increase in temperature in the outer layer, the leak can be detected.

Another possibility for a leak detection device is that the solid, load-bearing outer layer is covered with a simple air-conducting cover made of film material, which, in the event of a fault, directs air flowing out to certain openings with temperature sensors. Since this outer shell made of foil material does not perform any insulating function, it is significantly easier to manufacture and assemble. A film reserve in the form of folds or embossing can be used to ensure that in the event of air escaping, there is enough space between the outer cover and the film or is formed by the differential pressure so that this air can flow to discrete openings in the film with leak detection sensors.

Advantageously, the inside of the insulation layer is designed as a smooth surface, which can be achieved by heat treatment, whereby webs of broken glass bubbles melt and the surface of the molten glass contracts to form a smooth surface. Here, the volume of the glass foam material decreases locally, so that an optionally mechanically processed blank must be produced with a corresponding oversize on the sides to be treated. Furthermore, the surface heat treatment must be dosed in such a way that the target geometry results after treatment and melting. The desired layer thickness of the glass foam material, which is no longer porous on the surface but is monolithic, can be influenced by this and by the size of the excess dimension provided. The heat treatment can be carried out, for example, using a laser or with a gas combustion or arc-based device, similar to welding or glassblowing work. The heat treatment can advantageously be carried out on the end faces of pipe ends in order to achieve a smooth surface for sealing the joint. In order to create not only a smooth surface on the end faces of the pipe ends, but also a flat one or one that fits geometrically exactly to a seal, the use of a hot stamp tool or similar can also be used to carry out the heat treatment. Around In order to avoid harmful tensile stresses in the workpiece, it can also make sense to either heat the blank as a whole to a higher temperature level during its surface processing and/or to carry out a heat treatment following the surface processing, similar to glass tempering processes.

The sandwich component proposed according to the invention can be used to enclose hot units, such as an APU (Auxiliary Power Unit) of an aircraft, for supply air or exhaust gases, or can be used to enclose associated silencers, which also become hot. The airtightness here is rather negligible, so that the sandwich components proposed according to the invention can also be produced in parts. In contrast to insulating wool, these have a solid structure, and as a result there is a solid connection layer on both sides, which offers advantages for fastening elements inside or for connecting to the structure outside. For example, fewer structural elements have to be passed through the insulation layer, which reduces thermal bridges.

A sandwich component proposed according to the invention with fiber ceramic on one side, an insulation layer made of glass foam material in the middle and fiber composite material as the outer layer can be used to house further hot units, such as a solid oxide fuel cell, or to increase the safety of potentially hot units, such as batteries, low-temperature fuel cells and other energy converters. The sandwich components proposed according to the invention can also be used as structural elements, for example serving as heat shields from the outside, for example in spacecraft for atmospheric re-entry or in supersonic aircraft. In this case, the fiber-ceramic cover layer is on the outside and the outer layer made of fiber composite material is on the inside of the missile.

Brief description of the drawings

The invention is described in more detail below with reference to the drawings. Show it

1 shows a sandwich component according to the invention, designed as a tube with an insulating layer made of glass foam material and an outer layer made of fiber composite material,

2 shows an embodiment variant of the sandwich component according to the invention with an additional layer of a fiber composite material with a ceramic or glass-like, inorganic matrix on the inside of the insulation layer,

Figure 3 shows a schematically indicated device for local temperature increase to smooth the inside of the insulation layer,

4 shows a sandwich component designed as a plate or panel and proposed according to the invention,

Figure 5 shows a cross section through a tubular sandwich component according to the invention with attachments or internals on the cold side and hot side,

Figures 6a - 6d show a manufacturing process of a sandwich component designed in the form of a tube,

Figure 7 shows a sandwich component, designed as a tube,

Figure 8 shows a sandwich component, also designed as a tube, enclosed by an air-guiding sleeve and

Figures 9 and 9.1 show a sandwich component, also designed as a tube, with fiber-optic sensors laminated into the outer layer.

Implementation variants of the invention

In the following description of the embodiments of the invention, the same or similar elements are referred to with the same reference numerals, with a repeated description of these elements being omitted in individual cases. The figures represent the subject matter of the invention only schematically. Figure 1 shows a sandwich component 50 designed as a tube 24 and proposed according to the invention.

The illustration according to Figure 1 shows that the sandwich component 50 proposed according to the invention is designed in the form of a tube 24. As shown in Figure 1, the sandwich component 50 is exposed to a cold side 20 and a hot side 22. The cold side 20 can, for example, be the environment where ambient temperature prevails, while on the hot side 22 the flow cross section of the tube 24, for example, has hot air or another hot gas flowing through it. Higher temperatures therefore prevail in the flow cross section of the pipe 24 than on its outside, the cold side 20.

The sandwich component 50 in the form of the tube 24 contains a surrounding insulation layer 54, which comprises a gas-tight, high-temperature-resistant glass foam material 10. Furthermore, the sandwich component 50 designed as a tube 24 according to FIG. 1 comprises an outer layer 52, which is designed as a fiber composite material. 1, a glass layer 14 is formed on the inside of the insulation layer 54 facing the hot side 22, which forms the surface of the gas-tight, high-temperature-resistant glass foam material 10, which determines the flow cross section of the tube 24, i.e. H. whose cavity is limited.

Figure 2 shows an alternative embodiment variant of the sandwich component 50 proposed according to the invention, which is also designed as a tube 24 according to Figure 2. The sandwich component 50 includes an outer layer 52 which comprises a fiber composite material 12. The outer layer 52 encloses said insulation layer 54, which comprises a gas-tight, high-temperature-resistant glass foam material 10. On its glass layer 14, a further layer in the form of a fiber composite material 16 with, for example, a ceramic matrix or with a glass-like, inorganic matrix is applied, glued, soldered or laminated on.

While according to Figure 1, the sandwich component 50 designed as a tube 24 has a glass layer 14 as the surface of the insulation layer 54 on its inside, which limits the flow cross section and is exposed to the hot side 22, In the illustration of the exemplary embodiment according to FIG. 2, a sandwich component 50 is shown, which can be exposed to higher temperatures and/or mechanical loads. In the event that the expected loads on the side of the sandwich component 50 designed for high temperatures are such that they cannot be absorbed by the insulation layer 54 alone or by a glass layer present after surface treatment alone, with the exemplary embodiment according to FIG the hot side 22 of the sandwich component 50 can be fiber-reinforced. In order to obtain a sandwich construction with glass foam material 10 and fiber reinforcement on both sides, a layer of fiber composite material 16 with a ceramic matrix or with a glass-like, inorganic matrix is applied to the hot side 22 of the insulation layer 54, ie on the glass layer 14. This can be done, for example, by laminating directly onto the insulation layer 54, which comprises a gas-tight, high-temperature-resistant glass foam material 10. The laminated layer and the glass foam material 10 are then heat treated together for consolidation or curing or for pyrolysis of the fiber composite material 16 with a ceramic matrix or with a glass-like, inorganic matrix, if the temperature resistance of the foam glass material 10 is high enough for the process necessary for the curing. Alternatively, it is possible to apply a previously separately produced layer of fiber composite material 16 with a ceramic matrix or with a glass-like, inorganic matrix to the glass layer 14 of the insulation layer 54 by means of an adhesive process or a glass soldering process, in which case an adhesive or a glass solder that is also resistant to high temperatures is then used can come.

In a variation of this exemplary embodiment, not shown, the glass layer 14 is omitted, and the layer of fiber composite material 16 with a ceramic matrix or with a glass-like, inorganic matrix is applied directly to the surface of the glass foam material 10 on the hot side 22 of the insulation layer 54.

3 shows a heat treatment of the glass layer 14 of the glass foam material 10 facing the hot side 22, which forms the insulation layer 54. From the illustration according to Figure 3 it can be seen that a device 18 for locally generating high temperatures for surface melting of the glass foam material 10 is used. The device 18 can be, for example, a laser or a device based on gas combustion or arc, similar to welding and glassblowing work. 3 shows that the device 18 is moved in a feed direction 92 along the glass layer 14 of the glass foam material 10. The outer area of the glass foam material 10, which is exposed to the heat treatment, melts together, any remaining open glass pores close and, due to the surface tension, the insulation layer 54, ie the glass foam material 10, shrinks from an oversize 96 to a target size 98. In addition to reducing the thickness of the insulation layer 54 from the oversize 96 to the target size 98, the glass layer 14 becomes very smooth because the open glass pores are closed and, due to the surface tension, a very smooth inside of the glass foam material 10 forming the insulation layer 54 is formed , which assigns the hot side 22 of the insulation layer 54.

4 shows a further exemplary embodiment of the sandwich component 90 proposed according to the invention, which in this case is designed as a flat plate or panel. In the embodiment variant shown in Figure 4, the sandwich component 90 includes the insulation layer 54, which includes the gas-tight, high-temperature-resistant glass foam material 10. On the side facing the hot side 22, the insulation layer 54 of the sandwich component 90 is provided with the fiber composite material 16 with a ceramic matrix or with a glass-like, inorganic matrix, while on the cold side 20 the fiber composite material 12 is arranged as an outer layer 52, which is made of a very light and Fiber composite material 12 is thus manufactured with favorable weight properties for aircraft construction.

According to the embodiment variant in Figure 4, the sandwich component 90 can also serve as a heat or fire protection wall.

Figure 5 shows an embodiment variant of the sandwich component 50 proposed according to the invention, which is designed with a variable cross section. The sandwich component 50 shown in section in Figure 5 and also designed in the form of a tube 24 has a variable cross section. The hot side 22 is formed, for example, by the flow cross section of the tube 24, which is designed with a variable cross section and through which a hot air flow flows, for example. Resonator chambers 25, which serve to dampen sound, border the pipe 24 shown in dashed lines. The sandwich component 50 in the form of the tube 24 includes the insulation layer 54, formed from the gas-tight, high-temperature-resistant glass foam material 10, furthermore the fiber composite material 12 forming the outer layer 52 and, facing the hot side 22, the fiber composite material 16 with a ceramic matrix or with a glass-like, inorganic matrix, ie that Sandwich component 50 is designed in three layers in this exemplary embodiment.

5 shows that the sandwich component 50 in this embodiment variant can be connected, for example, via attachments 30, for example made of fiber composite material, on the cold side 20 under normal environmental conditions, for example with structural elements of an aircraft, in particular an airplane. Furthermore, Figure 5 shows that on the hot side 22 of the sandwich component 50, i.e. H. Attachments 28 are also arranged in the flow cross section of the pipe 24, which consist, for example, of a fiber composite material 12 with a CMC matrix and can therefore withstand high temperatures, such as those that can occur on the hot side 22 of the sandwich component 50.

5 shows that the tube 24 of the sandwich component 50, lying one behind the other in the axial direction, has several attachment parts 28 made of a fiber composite material 16 with a ceramic matrix or glass-like, inorganic matrix protruding from the inside of the fiber composite material 16 with a ceramic matrix or with a glass-like, inorganic matrix into the flow cross section . The diameter of the sandwich component 50 designed as a tube 24 is indicated by dashed lines. The insulation layer 54 includes the glass foam material 10, which is made from glass granules 62 with the addition of a foaming agent. To improve the strength, crack resistance or mechanical strength, fiber material in short form 58 or in long form 60 is added to the glass granulate 62, the fiber material being carbon, metal (for example steel or nickel-based superalloys), basalt or Ceramic fibers or high temperature resistant glass fibers can act. There is also the possibility of using 10 wound preforms (for later cover layers) or semi-finished textile products in the form of when producing the glass foam material Braid or fabric cover layers or in the form of spacer fabric are to be inserted, which are then penetrated by the glass granulate 62 in the melting and foaming process, supported by the foaming agent. Such a manufacturing process can be seen, for example, in the sequence of figures in FIGS. 6a to 6d.

From the illustration according to Figure 6a it can be seen that dry reinforcing fibers 32 assigned to the inner tube surface are wound around an inner shape 34. The inner molded part 34 can, for example, be divisible, have a demolding slope or the like, or enable demolding due to a difference in thermal expansion. In the latter case, this can be achieved, for example, by selecting a material for the material of the inner molded part 34 that has a higher thermal expansion than the material of the workpiece solidified after the shaping process, so that the inner molded part 34 contracts more strongly during the cooling process the workpiece.

Figure 6b shows how dry reinforcing fibers assigned to the outer tube surface are wound around a preform 36, which represents a hollow component, after or independently of the previously described process. The hollow preform 36 comprises a mixture of glass granules 62 with foaming agent and a binding material. Furthermore, the granules 62 can contain short fibers 58 or long fibers 60 if these are needed as crack stoppers in the glass foam material 10 to be foamed. The fibers applied according to Figure 6b are not the same as those in Figure 6a, but are new fibers which later form an outer cover layer. The hollow preform made of glass granules, foaming agent and binding material is needed as a support for winding in order to hold the fibers on the circumference of the outer diameter, since a cavity is still needed in the mold for space to foam the foam glass. The inner fiber layer remains wound on the inner mold after the foaming process until the finished component is removed from the mold.

The preform 36 prepared according to Figure 6b is either produced around the preform 36 prepared according to Figure 6a or the preforms 36 produced according to Figures 6a and 6b are manufactured separately and then joined together, for example by pushing them into one another. The combination of both preforms 36 is, as described below, in transferred to a closed mold 100, whereby the inner molded part 34 described in FIG. 6a can represent a part of this closed mold.

Figure 6c shows that the closed mold 100 is designed to be divisible and includes a first mold half 102 and a second mold half 104.

The inner mold 34 prepared according to Figure 6a is enclosed by the closed mold 100 or its mold halves 102 and 104 and both preforms 36 are joined together into a closed mold 100. For this purpose, a heating process takes place to approximately 800 ° C, in which it becomes a melting and foaming of the glass granules 62 occurs, so that the fiber layers of the dry reinforcing fibers 32 are saturated.

In the illustration according to Figure 6c, reference number 40 denotes an expansion during the foaming process. The space for foaming is limited by the annular area between the dry reinforcing fibers 32 on the circumference of the inner mold 34 and on the other hand by the inside of the glass foam material 10 to be foamed.

After the foaming process has ended, a blank of a sandwich component 90 made of fiber ceramic or fiber-reinforced glass, foam glass and fiber composite material 12 is obtained. The sandwich component 90 shown in Figure 6d therefore comprises an outer layer 52 made of fiber composite material 12, which covers the insulation layer 54 made of foamed glass foam material 10, which in turn is covered on its side facing the hot side 22 with the fiber composite material 16 with a ceramic matrix or glass-like, inorganic Matrix is covered. The resulting blank shown in Figure 6d is cooled and removed from the mold and has a near-net-shape foam glass sandwich structure with fiber-reinforced outside and inside.

According to an alternative embodiment of the process described in Figures 6 a to 6 d, the reinforcing fibers 32 can also have already been completely or partially impregnated with a glass-shaped matrix in advance, so that they are in the form of flat prepreg tapes and in this form in the processes described on the inner mold 34 or the preform 36 can be wrapped. In this case, the glass from the glass granules has not penetrated into the fiber cover layers during the foaming process, or has not penetrated so deeply, which may have advantages with high-viscosity glasses.

The sandwich component 50, 90 described above with reference to Figures 1 to 6d or its manufacturing process enables the use of the glass foam material 10 as an insulation layer 54 on the hot side 22 and the use of a fiber composite material 12 as an outer layer 52 on the cold side 20. The outer layer 52 made of fiber composite material takes over 12 the tensile load that can arise, for example, due to internal pressure in the tube 24, and not the inner tube as usual. The gas-tight, high-temperature-resistant glass foam material 10, on the other hand, takes on the task of sealing the pipe 24 in addition to the insulating function, so that this function cannot be ensured by the fiber composite material 12. The described sandwich component 50, which is designed as a tube 24, has the advantage that materials can be used for the outer layer 52 that have a lower temperature resistance than would be the case for an inner shell in contact with a hot gas stream on the hot side 22. Since a significantly larger selection of fiber composite materials is available, materials with better mechanical properties and/or lower prices or lower processing costs can also be used. The glass foam material 10 in turn has the advantage that it hardly outgases and therefore the hot medium is not contaminated with vapors.

The sandwich component 50 proposed according to the invention can be expanded in such a way that it can be provided with a leak detection device 66. For this purpose, air channels 76 can be introduced on the outside of the insulation layer 54, which contains a gas-tight, high-temperature-resistant glass foam material 10, which can be done, for example, by milling or molding. These remain air-permeable even after the outer layer 52 has been laminated in the form of the fiber composite material 12 and, in the event of a leak in the insulation layer 54, direct air escaping there to the discrete air outlet points 68 located in a fiber composite shell 78. There are temperature sensors 72 in front of these. The sandwich component 50 therefore takes over In addition, the task of a non-structural air duct envelope that would otherwise be located further out, which can be saved in this case. The discrete air outlet points 68 are dimensioned such that the ability of the outer shell to absorb the circumferential forces through the Taking up internal pressure is still guaranteed. The cell walls of the foam glass and any fibers embedded in it are dimensioned so that the cells do not collapse despite the local pressure difference.

Another possibility for integrating a leak detection device 66 is to laminate fiber-optic sensors 82 into the outer structural fiber composite shell 78. Since in the event of a leak in the insulation layer 54, the hot air that then flows out causes a local temperature increase in the outer layer 52, the leak can be detected in this way , provided that the distance between the fiber optic sensors 82 is small enough so that the temperature influence area of a critical leak is not smaller than the grid of the arrangement of the temperature sensors 72.

Another possibility for integrating the leak detection device 66 can be seen in that the solid, load-bearing outer layer 52 is covered with a simple air-guiding cover made of film 84, which directs potentially escaping hot air to certain openings with temperature sensors 72. Since this outer shell no longer has an insulating function, it is significantly easier to manufacture and easier to install. A film reserve 88 in the form of folds or an embossing can be used to ensure that in the event of air escaping, there is enough distance between the outer cover and the film or is formed by the differential pressure so that this air can flow to discrete openings in the film with leak detection sensors 66 .

In the event that the insulation layer 54 is manufactured from a block material by mechanical processing, the surface of the insulation layer 54, which faces the hot side 22, is very rough. The surface of the glass foam layer 54 (insulation layer) consists of a number of webs of broken glass bubble cells. On the outside, where the outer layer 52 is laminated, this is advantageous in terms of the adhesion of the fiber composite material 12. However, a smooth surface on the inside of the insulation layer 54 is advantageous. It is also advantageous if there are no open glass pores 94 into which liquid could potentially penetrate. To achieve this, a heat treatment is carried out on the surface of the insulation layer 54 that faces the hot side 22. In the process, webs of broken glass pores 94 of the glass foam material 10 are melted, which contract to form a smoother surface due to the surface tension of the melted glass foam material 10. Since the volume of the glass foam material 10 decreases locally, the mechanically processed blank must be produced with a corresponding oversize 96 on the sides to be treated and the surface-effective heat treatment must be dosed in such a way that the desired target size 98 results after the heat treatment and contraction. The desired layer thickness of the glass foam material 10, which is no longer porous on the surface but rather monolithic, can also be influenced by the size of the excess 96 provided.

The surface treatment can be carried out, for example, using the device 18 in the form of a laser or with a device based on gas combustion or arc.

In particular, the heat treatment described can also be carried out on the end faces of the tube ends of the sandwich components 50 manufactured as tubes 24 in order to achieve a smooth surface for sealing the connecting joints between two tubes 24 to be connected to one another. In order to create not only a smooth surface, but also a flat one or one that fits geometrically exactly to a seal, the use of a hot stamp tool or similar can also be considered.

In order to prevent surface tensile stresses or other harmful tensile stresses in the insulation layer 54, which comprises a gas-tight, high-temperature-resistant glass foam material 10, it may make sense either to heat the blank as a whole to an increased temperature level during the surface treatment and/or to carry out a heat treatment following the surface treatment , similar to glass tempering processes.

In particularly temperature-intensive applications and in the event that expected loads on the hot side 22 of a sandwich component 50 are such that they cannot be absorbed by the insulation layer 54 or a glass layer 14 smoothed after surface treatment alone, fiber reinforcement can be carried out on the hot side 22 become. For this purpose, a fiber composite material 16 with a ceramic matrix or with a glass-like, inorganic matrix is used on the unprocessed surface of the insulation layer 54 on the side of the insulation layer 54 facing the hot side 22. Its construction can be done, for example, by direct laminating and subsequent temperature treatment of the laminated layer and the insulation layer 54 together for the consolidation and hardening or pyrolysis of the fiber composite material 16 with a ceramic matrix or with a glass-like, inorganic matrix, if the temperature resistance of the glass foam material 10 is high enough for that The above-mentioned fiber composite material 16 is a necessary process (e.g. glass soldering process).

The sandwich component proposed according to the invention can be used in hot gas lines, for air or exhaust gas routing or as an enclosure for hot units, such as an APU (Auxiliary Power Unit) of an aircraft; it can also be used as an enclosure for associated silencers. When used as an enclosure, airtightness plays a less important role, so that the sandwich components 50 can also be manufactured in parts in this case. However, one advantage can be seen in the fact that the sandwich component 50, in contrast to insulating wool, has a solid structure and therefore there is a solid connecting layer on both sides, which is used for fastening add-on elements (see positions 28, 30) or for connecting to external ones structures are suitable.

In a similar way, the sandwich component 50 proposed according to the invention can be made with a fiber composite material 16 with a ceramic matrix or with a glass-like, inorganic matrix of an insulation layer 54, which has a gas-tight, high-temperature-resistant glass foam material 10 and a fiber composite material 12 as an outer layer 52, for housing further hot aggregates, such as For example, a solid oxide fuel cell or for safety-enhancing housing of potentially hot units (e.g. in the event of a fault), such as batteries, low-temperature fuel cells or other energy converters.

Another application for the described sandwich component 50, 90 proposed according to the invention can be structural elements that serve as heat protection shields from the outside, for example in spacecraft, where they serve as heat protection during atmospheric re-entry or in supersonic aircraft. In this case, the side provided with the fiber composite material 16 with a ceramic matrix or glass-like, inorganic matrix is on the outside and the outer layer 52 made from the fiber composite material 12 is on arranged on the inside of the aircraft. In this application too, an adaptation of the principle of laminating fiber-optic sensors 82 described above, in this case possibly also in the fiber-ceramic cover layer or in the inner fiber composite material layer in this case or in both, can serve to detect leaks or damage.

The outer layer 52 on the cold side 20, which is made of thermoset or thermoplastic fiber composite material 12, can only be applied or laminated on if processes with extremely high temperatures are not carried out afterwards, as are necessary for processing glass or ceramic material but only processes with temperatures within the normal processing range of the plastic fiber composite take place. Almost all common processes are used to apply the fiber composite material 12, which serves as the outer layer 52, such as thermoset prepreg-based processes, resin infusion processes, RTM processes (resin transfer molding transfer molding), thermoplastic prepreg-based processes, such as TP-based processes. AFP process (Thermoplastic Automated Fiber Placement), in question, as long as the mechanical and thermal loads, for example due to autoclave pressure, laying head contact pressure or due to temperature gradients, are not higher than the load limit of the glass foam material 10 used as the insulation layer 54.

The sandwich component 50, designed as a tube 24, can be seen in FIGS. 7 and 7.1. The hot side is designated by reference number 22, while the cold side is designated by reference number 20. Starting from the hot side 22, a leak point 48 extends through which hot medium flows from the hot side 22 in the direction of the cold side 20 through the glass foam material 10, which forms the insulation layer 54, via air channels 76 in the direction of an outlet 68 in the area of the outer layer 22. Opposite the outlet 68 on the outer layer 52 is a temperature sensor 72. This senses the temperature increase that occurs due to the emerging hot medium. Figure 7.1 shows air channels 76 which cross one another and are embedded in the outer layer 52 of the sandwich component 50, which is also designed as a tube 24. The tube 24 has end faces 86 on which the tube 24 can be integrated into a line at corresponding joints or connected to other tubes. Figure 8 shows that the sandwich component 50, which is also designed here as a tube 24, is enclosed by an air-guiding cover 84, for example made of a film material. As can be seen from Figure 8, the air-conducting sleeve 84 has film reserves 88 at, for example, opposite locations, so that if the medium escapes via a leak in the foam glass layer and the fiber composite layers, it is caught by the air-conducting sleeve 84 and, thanks to the existing reserve 88, there is a gap between outer fiber composite layer and the air guide cover 84 can form, so that the air flows through this gap to one of the outlets 68 and only there exits to the outside. Also in Figure 8, the sandwich component 50, designed as a tube 24, is flowed through by a medium on the hot side 22. Analogous to the illustration according to FIG. 7, a temperature sensor 72 is also assigned to the outlet 68. The sandwich component 50 includes, in addition to the glass foam material 10, the fiber composite material 12 as an outer layer 52 on its inside, the fiber composite material 16 with a ceramic matrix or with a glass-like, inorganic matrix.

9 and 9.1 it can be seen that the sandwich component 50, here also designed as a tube 24, can include fiber-optic sensors 82 laminated into its outer layer 52. These are on the outside of the tube 24, i.e. H. arranged on the outer layer 52, analogous to the course of air channels 76 (see illustration according to Figure 7.1). The sandwich component 50 shown in Figure 9 in the form of the tube 24 is one which is constructed analogously to the sandwich component 50 according to Figure 7, namely the glass foam material 10 as an insulating layer 54 and the fiber composite material 12 as the outer layer 52. In the outer layer The fiber optic sensors 82 are laminated into 52.

The course of the arrangement of the fiber-optic sensors 82 can correspond to the course of the air channels 76, but this is not absolutely necessary. With the air ducts 76, for example, it makes sense if they cross each other regularly; In the case of fiber-optic sensors 82, a close-meshed, spiral-shaped winding in only one direction can also be considered without crossing over. The air channels 76 according to FIG. 7 are located in the foam glass layer, while the fiber-optic sensor genes 82 according to FIG. 9 can be assigned to the outer fiber composite layer. The invention is not limited to the exemplary embodiments described here and the aspects highlighted therein. Rather, within the range specified by the claims, a large number of modifications are possible, which are within the scope of professional action.

Reference symbol list

10 glass foam material

12 fiber composite material

14 glass layer on the surface of the glass foam material

16 fiber composite material with ceramic or glass-like, inorganic

matrix

18 Device for locally generating high temperatures

20 cold side

22 hot side

24 pipe

25 resonator chambers

26 plate, panel

28 attachments building structure or system on hot side

30 attachments made of fiber composite material on the cold side

32 Dry reinforcing fibers

34 Inner shape

36 preform

38 external shape

40 expansion during the foaming process

48 leak point

50 sandwich component

52 outer layer or layer on the cold side

54 insulation layer

56 fiber material (metal, basalt, glass, carbon and ceramic fibers)

58 short fibers

60 long fibers

62 glass granules

64 Textile semi-finished products

66 leak detection device

68 outlet

70

72 temperature sensor

74

76 air channels in outside insulation layer

78 fiber composite cover Laminated fiber optic sensors

Air guide cover made of foil

front side

Foil reserve

Sandwich component made of fiber composite material with inorganic

Matrix, foam glass and general composite material

feed direction

Open glass pores

excess

Target size

Closed form

First half of the mold

Second half of the mold

Claims

Patent claims

1. A method for producing an at least two-layer sandwich component (50) in the form of a tube (24) or in the form of a plate (26), the sandwich component (50) being exposed to a cold side (20) and a hot side (22), with at least the following method steps: a) producing an insulation layer (54) facing the hot side (22) from a gas-tight, high-temperature-resistant glass foam material (10) and b) producing an outer layer (52) of the sandwich component (50) facing the cold side (20), a Fiber composite material (12) containing.

2. The method according to claim 1, characterized in that the insulation layer (54) facing the hot side (22) is provided with a layer which contains a fiber composite material (16) with a ceramic, glass ceramic or glass matrix material.

3. The method according to claims 1 or 2, characterized in that the insulation layer (54) facing the hot gas side (22) according to method step a), which comprises a gas-tight, high-temperature-resistant glass foam material (10), consists of a foam block material or a preform (36 ), the latter comprising at least one glass granulate (62) and a foaming agent.

4. Method according to claims 1 to 3, characterized in that the insulation layer (54) facing the hot side (22) is smoothed by locally generating high temperatures, such that after smoothing an open-pore-free glass layer (14) is obtained.

5. The method according to any one of claims 1 to 4, characterized in that the sandwich component (50) is held in a closed mold (100) during the implementation of at least method step a), in which the glass granules (62) are melted and foamed. Method according to claim 5, characterized in that in the closed mold (100) a fiber-containing layer (32) made from a fiber preform (36) or a temperature-resistant, porous fiber composite material (12) is completely or partially saturated with the melt of the glass granules (62). becomes. Method according to claims 1 to 6, characterized in that the gas-tight, high-temperature-resistant foam material (10) is provided during its production with fiber material, in particular carbon, metal (for example steel or nickel-based superalloy), basalt, ceramic fibers or temperature-resistant glass fibers, whereby the fiber material is present as short fibers (58), long fibers (60) or as continuous fibers. Method according to claim 7, characterized in that the fiber material is introduced as short fibers (58) or as long fibers (60) into the glass granulate (62) before it is melted or foamed or as a wound preform (36) for cover layers or as a semi-finished textile product, in particular as Braid or fabric cover layer or spacer fabric is introduced, which is soaked by the glass granules (62) during the melting and foaming process. Method according to claims 1 to 8, characterized in that a preform (36) is produced from a mixture comprising glass granules (62), foaming agent and binder, such that the preform (36) serves as a support for the application of further preforms (36). serves for one of the fiber cover layers and thus the position of the cavity into which the foam material expands during expansion and where the material to be cured and the fibers are located can be controlled by means of the preform(s) (36). Method according to claims 1 to 9, characterized in that air channels (76) are embedded on an outside of the insulation layer (54), which contains a gas-tight, high-temperature-resistant glass foam material (10), which remain air-permeable after the outer layer (52) has been laminated on and In the event of a leak in the insulation layer (54), air escaping is directed to discrete outlets (68) to which temperature sensors (72) are assigned. 11. Method according to claims 1 to 9, characterized in that fiber-optic temperature sensors (82) are laminated into the outer layer (52) of the fiber composite material (12) covering the insulation layer (54).

12. The method according to claim 4, characterized in that during the heat treatment of the insulation layer (54) facing the hot side (22), webs of broken glass bubbles (94) melt and contract to form a smooth surface due to surface tension or a predetermined surface geometry by pressing on a hot mold is produced.

13. The method according to claim 4 or 11, characterized in that the heat treatment is carried out on end faces (86) of the sandwich component (50) as a tube (24) in order to obtain smooth surfaces for sealing a joint between two tubes (24).

14. The method according to claim 2, characterized in that the fiber composite material (16) with a ceramic matrix or glass-like, inorganic matrix is laminated onto the insulation layer (54) facing the hot side (22) and a temperature treatment of the laminate and the insulation layer (54) together for the consolidation/curing/pyrolysis of this fiber composite material (16).

15. The method according to claim 2, characterized in that a prefabricated layer of the fiber composite material (16) with a ceramic matrix or with a glass-like, inorganic matrix by means of an adhesive process with a high-temperature-resistant adhesive or by means of a glass soldering process with a glass solder on the hot side (22) facing gas-tight, high-temperature-resistant insulation layer (54) is applied.

16. The method according to claims 1 to 15, characterized in that the fiber composite material (12) on the cold side (20) as an outer layer (52) using thermoset prepreg-based processes or resin infusion processes, RTM processes (resin transfer molding injection molding) or thermoplastic Prepreg-based processes, in particular TP-AFP processes (Thermoplastic Automated Fiber Placement), are applied. Sandwich component (50) in the form of a tube (24) or in the form of a plate (26), which is exposed to a cold side (20) and a hot side (22), produced according to one of claims 1 to 16, characterized in that the sandwich component (50) is designed in at least two layers and comprises an insulation layer (54) facing the hot side (22), which comprises a gas-tight, high-temperature-resistant glass foam material (10), and an outer layer (52) made of a fiber composite material (12) facing the cold side (20). . Sandwich component (50) according to claim 17, characterized in that the insulation layer (54) facing the hot side (22), which comprises a gas-tight, high-temperature-resistant glass foam material (10), is provided with a layer which is a fiber composite material (16) with a ceramic matrix or with a glass-like, inorganic matrix. Use of the sandwich component (50) according to claims 17 or 18 in an aircraft as a hot gas line or as a bleed air line or as an exhaust line or as an engine or as an APU silencer (APU = Auxiliary Power Unit). Use of the sandwich component (50) according to claims 17 or 18 for housing potentially hot units in regular operation and/or in the event of a fault or fire in an aircraft, in particular a solid oxide fuel cell or at least one battery or a low-temperature energy converter.