Preparation method of high-temperature-resistant resin-based composite sandwich structure

Abstract

The invention discloses a preparation method of a high-temperature-resistant resin-based composite sandwich structure, and belongs to the technical field of composite material molding, and the preparation method comprises the following steps: S1, preparing prepreg and rigid foam for preparing the sandwich structure; s2, the rigid foam is cut according to the design requirements of the complex structure workpiece, and then a plurality of supporting bodies are obtained; s3, the multiple supporting bodies are subjected to surface treatment, and multiple core materials are formed through laying of prepreg; s4, after the multiple core materials are subjected to hot compaction treatment, according to the design requirements of the complex structure workpiece, the multiple core materials are spliced to form a prefabricated body, covering is laid on the prefabricated body through prepreg to form a to-be-cured prefabricated body, and S5, the to-be-cured prefabricated body is subjected to hot curing treatment to form the workpiece of the sandwich structure; by means of the mode, the high-temperature-resistant, high-performance and light-weight application scene requirements of an aerospace force-bearing structure are effectively met, and meanwhile the high-temperature-resistant, high-performance and light-weight aerospace force-bearing structure can adapt to preparation of a complex structure.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of composite material forming, and in particular to a preparation method of a high-temperature-resistant resin-based composite sandwich structure. BACKGROUND

[0002] With the development of composite material manufacturing technology, the lightweight structure of aerospace products and excellent performance are important goals in the development of aerospace technology. In the field of aviation and aerospace, the weight, performance and economy of products are closely related to each other. The traditional load-bearing structure parts are metal materials, but the weight is large. The traditional lightweight sandwich structure parts use an epoxy resin system, but the temperature resistance is low. In the aerospace field, some complex products use assembly technology, but there are quality risks in the assembly of the high-temperature-resistant composite parts through gluing and riveting. With the development of aerospace products, the performance requirements of structural parts are becoming more and more stringent. Therefore, it is of great significance to develop a high-temperature-resistant (temperature resistance 350 DEG C), high-performance and lightweight composite part. Patent No. CN 115214874 A "Anti-deformation composite wing surface sandwich foam structure and preparation method thereof" mainly improves the forming process of the anti-deformation wing surface sandwich structure. The forming process of the sandwich structure in the patent does not involve high-temperature-resistant composite materials, and the forming of the sandwich structure of high-temperature-resistant composite materials is not involved. Patent No. CN 119189458 A "High-temperature-resistant foam sandwich structure and manufacturing method thereof" mainly uses polyimide foam and polyimide composite panels to be bonded and co-cured through a polyimide adhesive film, which is mainly suitable for simple structures, and there are quality risks in the forming of complex structures. Patent No. CN 110978560 A "Foam sandwich structure wallboard and forming method thereof" mainly focuses on the forming process of the foam sandwich structure wallboard, and the high-temperature-resistant material system and the forming technology of complex structures are not studied.

[0003] In the application of materials in aerospace products, high-temperature-resistant materials (temperature resistance >= 350 DEG C) mainly include metal materials, and some use polyimide resin-based composites. However, the weight of metal materials is too large, the forming process of polyimide composites is difficult, and especially the forming quality of complex structures is difficult to guarantee. In the application of structures in aerospace products, the traditional composite load-bearing structure mainly uses the assembly process of gluing-riveting or mutual combination, and mainly uses the epoxy composite system. The assembly process is complex and has assembly risks, and the composite system has the characteristics of insufficient temperature resistance, and can only be applied to low-temperature-resistant composite structures. The traditional high-temperature-resistant part structure mainly uses metal materials, which has the characteristics of large weight and high manufacturing cost. For the forming of some complex composite structures, such as the method of directly connecting and curing after splicing, there are hidden dangers in the uniformity of the connection, and the splicing part is prone to collapse, which affects the structural performance.

[0004] Therefore, aiming at the application requirement of high-temperature-resistant resin matrix composite system on high-temperature-resistant, high-performance and lightweight bearing structure, the application aims to study a preparation method of a high-temperature-resistant resin matrix composite sandwich structure, so that the prepared high-temperature-resistant resin matrix composite sandwich structure has weight advantage compared with traditional metal materials, has temperature-resistant performance and molding process advantage compared with traditional epoxy, bismaleimide and polyimide composite materials, provides an effective method or way for the bearing structure, lightweight support structure and wave-transparent cover of the aerospace field high-temperature-resistant scene, and meets the requirements of high performance, high temperature resistance and lightweight. SUMMARY

[0005] The technical problem to be solved by the application is to effectively meet the application scene requirement of high-temperature-resistant, high-performance and lightweight aerospace bearing structure, and to adapt to the preparation of complex structures.

[0006] The technical scheme adopted by the application to solve the technical problem is: a preparation method of a high-temperature-resistant resin matrix composite sandwich structure, comprising the following steps: S1: preparing prepreg for preparing the sandwich structure and hard foam, the prepreg being a resin matrix composite material; S2: cutting the hard foam according to the design requirements of the complex structure part, thereby obtaining a plurality of support bodies; S3: surface treating the plurality of support bodies, forming a plurality of core materials through the laying of the prepreg, and the laying number of the core materials is 50-100 layers; S4: after heat compaction treatment of the plurality of core materials, according to the design requirements of the complex structure part, splicing the plurality of core materials to form a preform, wherein a prepreg strip made of the prepreg is filled in the splicing gap between the core materials during the splicing process, and a skin is laid on the preform by using the prepreg to form a to-be-cured preform, and the laying number of the skin is 20-27 layers; S5: heat curing the to-be-cured preform to form the part of the sandwich structure.

[0007] As a preferred technical scheme of the application, the laying number of the core material is 60 layers.

[0008] As a preferred technical scheme of the application, the laying number of the skin is 20 layers.

[0009] As a preferred technical scheme of the application, the core material is pre-pressed and compacted by using a vacuum bag every 5-15 layers of laying.

[0010] As a preferred embodiment of the present invention, the hot pressing temperature in the hot pressing process is 80℃~120℃, the holding time is 30min~60min, the hot pressing vacuum pressure is 0.1MPa~0.6MPa, and the heating / cooling rate is 1℃ / min~3℃ / min.

[0011] As a preferred technical solution of the present invention, the skin is pre-compacted by vacuuming using vacuum bags every 5-15 layers.

[0012] As a preferred embodiment of the present invention, the surface treatment of the plurality of supports in step S3 specifically includes: The surfaces of several supports are cleaned, and then a resin film is applied to the prepreg application area of ​​several supports, the thickness of which is 0.1mm to 1.0mm.

[0013] As a preferred embodiment of the present invention, the surface treatment of the plurality of supports in step S3 specifically includes: The surfaces of several supports are cleaned, and then resin is applied to the areas of several supports where the prepreg is laid, with the resin thickness being 0.1 mm to 1.0 mm.

[0014] As a preferred embodiment of the present invention, the rigid foam is rigid polyimide foam with a closed-cell rate of 80%~95% and a density of 100 kg / m³. 3 ~180kg / m 3 .

[0015] As a preferred embodiment of the present invention, the resin-based composite material is a phthalonitrile resin prepreg, wherein the resin content of the prepreg is 35%~42%, and the fiber areal density of the reinforcement in the prepreg is 100~250 g / m³. 2 .

[0016] The beneficial effects of this invention are reflected in: This invention provides a method for preparing a high-temperature resistant resin-based composite sandwich structure. Compared with existing technologies and processes, this method offers superior high-temperature resistance, lightweight design, and simplified molding process. It is also adaptable to the fabrication of complex structures. The method involves preparing a core material by laying pretreated rigid foam with phthalic acid resin prepreg, then assembling the core material into a preform to be cured. The sandwich structure is then integrally cured using a thermosetting process, resulting in a sandwich structure with significant high-temperature resistance and lightweight characteristics, while reducing the problems exposed by traditional machining and assembly processes. The structure can be applied to rudder structures, lightweight support structures, and wave shield structures in the aerospace field. Compared with the splicing method of adhesive bonding and riveting, on the one hand, the adhesive of adhesive bonding cannot meet the temperature requirement of 350℃, and on the other hand, the riveting method can cause splitting problems when machining holes in composite materials. Compared with the molding method of directly laying the skin after splicing composite materials, by filling the splicing gaps with prepreg strips, problems such as uneven fusion during heat curing and collapse at the splicing gaps are avoided. Compared with metal as the main material, it has advantages in weight and cost. Attached Figure Description

[0017] Fig. 1 This is a schematic diagram of the rigid foam of the present invention after being shaped and surface-treated as required. Fig. 2 These are schematic diagrams showing the front and top views of the core material and skin covering of the present invention. Fig. 3 This is a schematic diagram showing the results of ultrasonic C-scan, CT scan longitudinal section, and CT scan cross section for detecting the internal molding quality of the high-temperature resistant resin-based composite sandwich structure of the present invention.

[0018] In the diagram: 1. Rigid foam; 2. Resin; 3. Prepreg; 4. Prepreg strip. Detailed Implementation

[0019] The invention will now be described in further detail with reference to the accompanying drawings.

[0020] Combined with appendix Figs. 1-3 As shown, a method for preparing a high-temperature resistant resin-based composite sandwich structure includes the following steps: S1: Prepare the prepreg 3 and rigid foam 1 for preparing the sandwich structure. The prepreg 3 is a resin-based composite material. Specifically, the rigid foam 1 is rigid polyimide foam with a closed-cell rate of 80%~95% and a density of 100 kg / m³. 3 ~180kg / m 3, the resin-based composite material is a phthalonitrile resin prepreg, the resin content of the prepreg 3 is 35%-42%, and the reinforcing body of the prepreg 3 is a continuous fiber, specifically, the continuous fiber can be selected from carbon fiber, glass fiber, quartz fiber, and polymer fiber, and the fiber area density of the continuous fiber is 100-250 g / m 2 , or the resin-based composite material is a phthalonitrile resin prepreg, the resin content of the prepreg 3 is 35%-42%, and the reinforcing body of the prepreg 3 is a fabric cloth, and the fiber area density of the fabric cloth is 100-250 g / m 2 , preferably, the closed cell rate of the rigid polyimide foam is 90%, and the density is 150 kg / m 3 , the resin content of the phthalonitrile resin prepreg is 40%, the reinforcing body is carbon fiber, and the fiber area density is 100 g / m 2 ; S2: cutting the rigid foam 1 according to the design requirements of the complex structure part to obtain a plurality of support bodies, preferably, the rigid foam 1 is cut by machining, and the support bodies are used for supporting the inside of the sandwich structure; S3: surface treatment is performed on the plurality of support bodies, wherein the surface treatment includes cleaning the surfaces of the plurality of support bodies, and then, a resin 2 film is attached to the laying area of the prepreg 3 on the surfaces of the plurality of support bodies, the thickness of the resin 2 film is 0.1 mm-1.0 mm, or the surfaces of the plurality of support bodies are cleaned, and then, resin 2 is applied to the laying area of the prepreg 3 on the surfaces of the plurality of support bodies, the thickness of the resin 2 is 0.1 mm-1.0 mm, preferably, the resin 2 is phthalonitrile resin, and the thickness of the adhesive layer is 0.5 mm, a plurality of core materials are formed by laying the prepreg, specifically, the prepreg 3 is laid on the support bodies according to the quasi-isotropic laying sequence of [0 / 45 / 90 / -45], wherein quasi-isotropy is a characteristic of a composite laminated plate that exhibits the same stiffness in each direction in the plane, the core material is pre-compacted by vacuumizing every 5-15 layers of laying, specifically, the core material is pre-compacted by vacuumizing every 5-15 layers of laying using a vacuum bag, preferably, the core material is pre-compacted by vacuumizing every 10 layers of laying, until a plurality of core materials are formed by laying, and the number of layers of the core material is 50-100 layers, preferably, the number of layers of the core material is 60 layers; S4: after the heat compaction treatment of the plurality of core materials, wherein the heat compaction treatment has a heat pressing temperature of 80-120°C, a holding time of 30-60 min, a vacuum pressing pressure of 0.1-0.6 MPa, and a heating / cooling rate of 1-3°C / min, preferably, the heat compaction treatment has a heat pressing temperature of 100°C, a holding time of 30 min, a vacuum pressing pressure of 0.3 MPa, and a heating / cooling rate of 1.5°C / min, according to the design requirements of the complex structure part, the plurality of core materials are spliced to form a preform, wherein, in the splicing process, the splicing gap between the core materials is filled with a prepreg strip 4 made of the prepreg 3, specifically, the prepreg strip 4 is twisted from a phthalocyanine resin prepreg with continuous fibers as a reinforcing body, and can have a columnar or long strip shape, or other strip structures, by filling the splicing gap of the heat-compacted core materials with the prepreg 3, and filling the prepreg strip 4 according to the shape and size of the gap, the right-angle gap of the core material is ensured to have no obvious gap defects, and the prepreg 3 is used to lay the skin on the preform to form a to-be-cured preform, specifically, the prepreg 3 is used to lay the skin on the core material according to the quasi-isotropic lay-up sequence of [0 / 45 / 90 / -45], wherein quasi-isotropy is a characteristic of a composite laminated plate having the same stiffness in each direction in the plane, the skin is pre-compacted by vacuumizing every 5-15 layers of laying, specifically, the skin is pre-compacted by vacuumizing every 5-15 layers of laying using a vacuum bag, preferably, the skin is pre-compacted by vacuumizing after every 10 layers of laying, until the to-be-cured preform is formed after the laying is completed, and the number of layers of the skin is 20-27, preferably, the number of layers of the skin is 20; S5: the to-be-cured preform is subjected to a heat curing treatment to form the part of the sandwich structure, wherein the heat curing treatment includes a first stage of heat pressing tank curing forming treatment and a second stage of high temperature baking oven curing treatment; Specifically: S5.1: the to-be-cured preform is placed in a heat pressing tank for the heat pressing tank curing forming treatment and cured to 240-260°C, then cooled and demolded to form a cured and formed composite sample; The preform to be cured is placed in a hot press tank, the hot press tank is heated from room temperature to 100-150°C, and held for 30-60 minutes, then heated to 170-200°C, and held for 60-120 minutes, and then pressurized to 0.5-1.0 MPa during holding, then pressure is maintained, then heated to 240-260°C, and held for 120-300 minutes, and then cooled to below 60°C to release the mold after holding, the pressure is maintained until the temperature is lowered to release the mold, and the heating / cooling rate is 1-3°C / min. Preferably, the hot press tank curing forming process is as follows: the hot press tank is heated from room temperature to 150°C, held for 60 minutes, then heated to 170°C, held for 60 minutes, then pressurized to 0.6 MPa during holding, then heated to 200°C, held for 120 minutes, then heated to 250°C, held for 300 minutes, and then cooled to 30°C to release the mold after holding; S5.2: The composite sample is placed in a high-temperature baking oven for curing to 315-375°C, and then cooled to form a product. The high-temperature baking oven curing process improves the cross-linking degree of the composite sample, thereby improving the high-temperature resistance of the composite sample. The composite sample is cured and cross-linked in the high-temperature baking oven after being cooled and demolded after the hot press tank curing forming process. The high-temperature baking oven is heated from room temperature to 280°C, held for 5-15 hours, then heated to 315-375°C, held for 1-5 hours, and then cooled to below 60°C to remove the product. The heating / cooling rate is 1-3°C / min. Preferably, the high-temperature baking oven curing process is as follows: the high-temperature baking oven is heated from room temperature to 280°C, held for 5 hours, then heated to 350°C, held for 5 hours, and then cooled to 30°C. The heating / cooling rate is 1.5°C / min. S6: The formed product is subjected to quality detection by non-destructive methods. Specifically, ultrasonic C-scan non-destructive testing is used in combination with CT scan non-destructive testing.

[0021] The drawings are combined Figs. 1-3 As shown in the drawings, the following prepreg 3 and rigid foam 1 are used as an example. The high-temperature resistant resin prepreg uses phthalonitrile resin as the matrix and carbon fiber as the reinforcing body to prepare a unidirectional prepreg 3. The resin content is 40%, and the fiber area density is 100 g / m 2 . The foam uses polyimide rigid foam with a density of 150 kg / m 3 . The rigid foam 1 is machined according to the required size. The prepreg 3 is coated with phthalonitrile resin in the laying area, and the adhesive layer thickness is 0.5 mm. Fig. 1 ​The core material is prepared by laying the prepreg 3 on the hard foam 1, and the laying is performed according to the quasi-isotropic layering sequence of [0 / 45 / 90 / -45 / 0], and the core material prepreg 3 is pre-pressed by vacuum every 10 layers; The laid core material is spliced and hot-pressed, the hot-pressing temperature is raised from room temperature to 100℃, the holding time is 30min, the vacuum pressure is 0.3MPa, and the heating / cooling rate is 1.5℃ / min; the splice gap of the hot-pressed core material is filled with a prepreg strip 4 made of the prepreg 3, the prepreg strip 4 is filled according to the shape and size of the gap, the prepreg strip 4 is a twisted strip made of o-dianiline resin prepreg with continuous fibers as the reinforcing material, and the shape is columnar or strip-shaped, etc.; The core material after splicing and hot-pressing is laid on the surface of the skin, the skin is laid according to the quasi-isotropic layering sequence of [0 / 45 / 90 / -45], and the laying is pre-pressed by vacuum every 10 layers, and the prepared body is prepared for curing after the laying is completed, and the prepared body is shown in the attached Fig. 2 ; The prepared body is heat-cured to form a product, and the heat-curing process is divided into two stages, the first stage adopts a heat-pressure tank curing forming process, the heat-pressure tank is heated from room temperature to 150℃, and the holding time is 60min, then heated to 170℃, and the holding time is 60min, the pressure is added when the holding time starts, the vacuum pressure is added to 0.6MPa, then heated to 200℃, and the holding time is 120min, then heated to 250℃, and the holding time is 300min, and the holding time is ended by cooling to 30℃ for demolding; the second stage adopts a high-temperature oven curing process, the high-temperature oven is heated from room temperature to 280℃, and the holding time is 5h, then heated to 350℃, and the holding time is 5h, the holding time is ended by cooling to below 60℃ to take out the product, and the heating / cooling rate is 1.5℃ / min; After the product is prepared, the forming quality of the sample is detected by a non-destructive method, specifically by ultrasonic C-scan non-destructive detection combined with CT scan non-destructive detection, and the internal forming quality of the sample is shown in the attached Fig. 3 ; The o-dianiline composite used in the prior art is assembled by traditional glue-riveting assembly process, on the one hand, there is no adhesive that can withstand 350℃ environment, on the other hand, the riveting method will cause splitting problem of the composite machining hole, and there are some technical problems in assembly, therefore, compared with the commonly used assembly process in the prior art, the application not only meets the requirement of high temperature resistance, but also realizes the preparation of complex structure.

[0022] The performance data of the high-temperature resistant resin matrix composite of the embodiment is shown in Table 1.

[0023]

[0024] Table 1 Composite properties The foregoing is considered as illustrative only of the principles of the application. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the application to the exact construction and practice described. Accordingly, all such variations are intended to be included within the scope of the present application as defined in the following claims, along with the full scope of equivalents to which such claims are entitled.

Claims

1. A method for preparing a high-temperature resistant resin-based composite sandwich structure, characterized in that, Includes the following steps: S1: Prepare a prepreg and rigid foam for the fabrication of the sandwich structure, wherein the prepreg is a resin-based composite material; S2: The rigid foam is cut according to the design requirements of the complex structural component to obtain several supports; S3: Surface treatment is performed on several of the supports, and several core materials are formed by laying the prepreg, wherein the number of core materials laid is 50-100 layers; S4: After hot-compacting several core materials, according to the design requirements of the complex structural component, several core materials are spliced ​​together to form a preform. During the splicing process, the splicing gaps between the core materials are filled with prepreg strips made of the prepreg. The prepreg is then used to lay a skin on the preform to form a preform to be cured. The number of skin layers is 20-27. S5: Perform thermosetting treatment on the preform to be cured to form the sandwich structure component.

2. The method for preparing a high-temperature resistant resin-based composite sandwich structure according to claim 1, characterized in that: The core material is laid in 60 layers.

3. The method for preparing a high-temperature resistant resin-based composite sandwich structure according to claim 1, characterized in that: The skin is laid in 20 layers.

4. The method for preparing a high-temperature resistant resin-based composite sandwich structure according to claim 1, characterized in that: The core material is pre-compacted by vacuuming every 5-15 layers using vacuum bags.

5. The method for preparing a high-temperature resistant resin-based composite sandwich structure according to claim 1, characterized in that: The hot pressing process involves a hot pressing temperature of 80℃~120℃, a holding time of 30min~60min, a hot pressing vacuum pressure of 0.1MPa~0.6MPa, and a heating / cooling rate of 1℃ / min~3℃ / min.

6. The method for preparing a high-temperature resistant resin-based composite sandwich structure according to claim 1, characterized in that: The skin is pre-compressed by vacuuming every 5-15 layers.

7. The method for preparing a high-temperature resistant resin-based composite sandwich structure according to claim 1, characterized in that: The surface treatment of the plurality of supports in step S3 specifically includes: The surfaces of several supports are cleaned, and then a resin film is applied to the prepreg application area of ​​several supports, the thickness of which is 0.1mm to 1.0mm.

8. The method for preparing a high-temperature resistant resin-based composite sandwich structure according to claim 1, characterized in that: The surface treatment of the plurality of supports in step S3 specifically includes: The surfaces of several supports are cleaned, and then resin is applied to the areas of several supports where the prepreg is laid, with the resin thickness being 0.1 mm to 1.0 mm.

9. The method for preparing a high-temperature resistant resin-based composite sandwich structure according to claim 1, characterized in that: The rigid foam is rigid polyimide foam with a closed-cell rate of 80%~95% and a density of 100 kg / m³. 3 ~180kg / m 3 .

10. The method for preparing a high-temperature resistant resin-based composite sandwich structure according to claim 1, characterized in that: The resin-based composite material is a phthalonitrile resin prepreg, the resin content of which is 35% to 42%, and the fiber areal density of the reinforcement in which the prepreg is 100 to 250 g / m³. 2 .

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