Preparation method of intelligent carbon fiber metal laminate

Abstract

The invention discloses a preparation method of an intelligent carbon fiber metal laminate, and belongs to the field of intelligent composite material forming, and the method comprises the following steps: printing a thermoplastic 3D printing sub-matrix with a preformed hole groove by using a continuous carbon fiber 3D printer; an optical fiber sensor is embedded into a reserved hole groove of the thermoplastic 3D printing sub-base body, and mold closing is carried out; performing surface treatment on the metal plate; the treated metal plate and the printing base body obtained after mold closing are placed in a mold according to a set layering mode; and hot pressing curing is conducted on the laid layer, and the intelligent carbon fiber metal composite laminate is obtained. A continuous fiber reinforced resin-based 3D printing matrix is used for replacing a prepreg tape to prepare the intelligent fiber metal laminate, a thermoplastic printing sub-matrix with a reserved space hole groove is subjected to 3D printing, and an optical fiber sensor is embedded into the hole groove, so that the sensor is three-dimensionally implanted in the fiber metal laminate; the layout of the optical fiber sensor can be freely designed, the limitation of preparation of the prepreg tape laying layer is broken through, and the overall state of the laminate is monitored.

Description

Technical Field

[0001] The present invention relates to the field of intelligent composite material forming, and in particular to a method for preparing an intelligent carbon fiber metal laminate. Background Art

[0002] Carbon fiber metal laminates are advanced structural materials made by alternating layers of metal materials (such as aluminum alloys and titanium alloys) and carbon fiber reinforced composites. They combine the high toughness and impact resistance of metal materials with the high specific strength, high specific stiffness, and excellent fatigue resistance of composite materials. This type of material has a wide range of applications in aviation, aerospace, automotive, and other fields, such as aircraft wing skins, tail structures, and other key load-bearing components. However, carbon fiber metal laminates may be affected by factors such as complex loads and environmental corrosion during long-term service, resulting in accumulated internal damage, which in turn leads to structural failure or even catastrophic accidents. Therefore, the development of intelligent carbon fiber metal laminates with structural health monitoring functions is of great significance to improving their service safety and reliability.

[0003] At present, the preparation of smart fiber metal laminates mainly adopts the process of prepreg plying combined with embedded sensors, that is, optical fiber sensors are embedded between the metal plate and the carbon fiber prepreg, and then cured and formed by autoclave. For example, in the prior art, optical fiber sensors are usually sandwiched between prepreg layers, or fixed to the surface of the metal plate with adhesives to achieve strain and temperature monitoring. However, the sensor layout of this method is limited by the plying method of the prepreg, making it difficult to achieve complex three-dimensional spatial distribution, and the adhesive may affect the interfacial bonding strength of the laminate. In addition, the prepreg preparation process is complex and the cost is high, which restricts the flexible manufacturing and wide application of smart fiber metal laminates.

[0004] The existing preparation methods of intelligent fiber metal laminates have the following major problems: (1) The sensor layout is limited. The prepreg lamination method makes it difficult to achieve a three-dimensional distribution of optical fiber sensors. They can only be arranged along a two-dimensional plane and cannot meet the multi-dimensional monitoring needs of complex structures; (2) The process compatibility is poor. The use of adhesives to fix sensors may reduce the interface bonding strength of the laminate and affect the overall performance of the material; (3) The manufacturing cost is high, the prepreg preparation process is complex, and it is difficult to achieve rapid customized production. Summary of the Invention

[0005] In response to the above problems, the present invention proposes a method for preparing intelligent carbon fiber metal laminates based on continuous carbon fiber 3D printing technology. By 3D printing a thermoplastic matrix with pre-reserved holes and grooves, the three-dimensional free layout of optical fiber sensors is realized, and a non-adhesive mechanical fixation method is adopted. While ensuring the interface bonding strength, the implantation accuracy and monitoring capability of the sensor are improved, breaking through the limitations of traditional prepreg processes, and providing a new technical solution for the flexible manufacturing and efficient monitoring of intelligent fiber metal laminates.

[0006] To this end, the present invention adopts the following technical solutions: In one aspect, the present invention provides a method for preparing a smart carbon fiber metal laminate, comprising the following steps: A thermoplastic 3D printed sub-matrix with pre-reserved holes and grooves is printed using a continuous carbon fiber 3D printer; the pre-reserved holes and grooves are arranged in a three-dimensional space and adapted to the parameters of the optical fiber sensor; Embedding the optical fiber sensor into the reserved hole groove of the thermoplastic 3D printing sub-matrix and closing the mold; Surface treatment of metal sheets; Place the processed metal plate and the printed substrate after mold closing in the mold according to the set layering method; The laminate is subjected to hot pressing and curing to obtain an intelligent carbon fiber metal composite laminate capable of sensing the strain exerted on the laminate and the change in its own temperature.

[0007] Furthermore, the thermoplastic 3D printing sub-substrate is a split structure, including an upper substrate and a lower substrate, and both the upper substrate and the lower substrate are provided with a partial hole groove structure.

[0008] Furthermore, the diameter of the holes and grooves formed after the thermoplastic 3D printed sub-substrates are molded matches the diameter of the optical fiber sensor.

[0009] Furthermore, the optical fiber sensor is embedded in the hole groove without the need for adhesive. Furthermore, the thermoplastic 3D printing sub-base is provided with positioning holes and positioning pins.

[0010] Furthermore, the hot pressing process uses a mold provided with an optical fiber positioning structure. Furthermore, the surface treatment of the metal plate includes chemical cleaning and anodizing treatment. Furthermore, the hot pressing molding process includes: placing the mold with the layer board placed in it into a vacuum bag, placing the vacuum bag into an autoclave, and controlling the temperature inside the autoclave through the autoclave program; the temperature control process is as follows: heating to 240°C at a heating rate of 5°C / min, and keeping warm for 10 minutes, then increasing the pressure to 0.2MPa at 0.02MPa / min, at which time the resin becomes viscous at this temperature, and under the action of pressure, the air is expelled and the optical fiber sensor is combined with the printing substrate, the printing sub-substrate itself, and the printing substrate and the metal plate, and then cooling to 40°C at 5°C / min, maintaining the pressure during the cooling process, and when it drops to 40°C, keeping warm for 10 minutes and reducing the pressure to 0MPa at a rate of 0.1MPa / min.

[0011] On the other hand, the present invention also provides an intelligent carbon fiber metal composite laminate prepared according to the above method.

[0012] The method for preparing the intelligent carbon fiber metal laminate provided by the present invention has the following beneficial effects: The present invention discloses a method for preparing an intelligent carbon fiber metal laminate, which comprises the following steps: using a continuous carbon fiber 3D printer to print out a continuous carbon fiber reinforced thermoplastic printed sub-matrix with reserved space holes and grooves; embedding optical fiber sensors into the holes and grooves of the printed matrix; surface treating the metal plate; closing the upper and lower molds of the printed sub-matrix with the embedded optical fiber sensors; placing the metal plate covered on the surface of the printed matrix into the mold, and preparing and molding in an autoclave. The prepared laminate can sense the strain exerted on the laminate and the change of its own temperature. The present invention uses a continuous fiber reinforced resin-based 3D printed matrix instead of a prepreg tape to prepare an intelligent fiber metal laminate, and by 3D printing a thermoplastic printed sub-matrix with reserved space holes and grooves, embedding the optical fiber sensors into the holes and grooves, so that the sensors are three-dimensionally implanted inside the fiber metal laminate. The layout of the optical fiber sensors can be freely designed, breaking through the limitations of the prepreg tape ply preparation, and realizing overall laminate status monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0014] Figure 1 Schematic diagram of a printed sub-base with three-dimensional holes and grooves and after mold closing in an embodiment of the present invention; Figure 2 Schematic diagram of the components of the smart carbon fiber metal laminate in an embodiment of the present invention; In the figure, 1. upper metal plate; 2. upper base; 3. lower base; 4. lower metal plate; 5. three-dimensional hole groove; 6. optical fiber sensor; 7. positioning pin; 8. positioning hole. DETAILED DESCRIPTION

[0015] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0016] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0017] This example provides a method for preparing an intelligent carbon fiber metal laminate. The printing substrate is Onyx, and the aluminum plate is 6061-T6, 1 mm thick. The fiber sensor used has an inner and outer diameter of 0.15 mm, a bare grating, no connectors, and a polyimide (PI) coating. The fiber has multiple grating points.

[0018] The specific process includes the following steps: S1, printing a thermoplastic continuous carbon fiber 3D printing matrix with pre-reserved holes and grooves; The printing layer thickness is 0.05mm, the height of the printed sub-substrate is 1.5mm, the overall height of the sub-substrate after mold closing is 3mm, the hole diameter is 0.15mm, the hole shape is semicircular, and it is circular after mold closing. The inside of the printed sub-substrate is filled with continuous carbon fiber, and the four corners of the sub-substrate are provided with positioning holes 8 and positioning pins 7. The schematic diagram of the printed sub-substrate is shown in the figure. Figure 1 The thermoplastic 3D printing sub-substrate is a split structure, including an upper substrate 2 and a lower substrate 3, and both the upper substrate 2 and the lower substrate 3 are provided with a partial hole groove structure.

[0019] S2, embedding the optical fiber sensor into the reserved hole groove of the thermoplastic 3D printing sub-substrate and closing the mold; In a specific implementation, the diameter of the hole formed after the thermoplastic 3D printed sub-substrate is molded matches the diameter of the optical fiber sensor 6. The optical fiber sensor 6 is embedded in the hole as follows: the optical fiber is embedded according to the preset layout, ensuring that the grating is fixed in the preset position, and the embedding is directly molded without gluing.

[0020] The positioning holes 8 and positioning pins 7 of the printed sub-base must be away from the embedding position of the optical fiber sensor 6. The hole parameters of the printed base must be compatible with the parameters of the optical fiber sensor 6. The reserved holes and slots are arranged in a three-dimensional space. The design and layout of the holes and slots should minimize the impact on the overall performance of the laminate.

[0021] S3, aluminum plate surface treatment; The treatment process specifically includes: (1) Decontaminating the surface of the aluminum plate with anhydrous ethanol. (2) Immersing the aluminum plate in a 200g / L sodium hydroxide solution for 3 minutes. (3) Shaking the aluminum plate after soaking with an ultrasonic cleaner for 2 minutes. (4) Putting the cleaned aluminum plate into a 200g / L nitric acid solution and soaking it for 3 minutes. (5) Shaking the aluminum plate after soaking with an ultrasonic cleaner for 2 minutes and drying it. (6) Anodizing the dried aluminum plate with a 200g / L phosphoric acid solution at a voltage of 10V, a current of 1A, and an anodizing time of 20 minutes.

[0022] S4. Laying of layers: Place the processed metal plates and the printed substrate after mold closing in the mold according to the set laying method.

[0023] The layering method is as follows: surface-treated aluminum plate, printed substrate after mold closing, and surface-treated aluminum plate.

[0024] S5. Hot-pressing and curing the laminate to obtain an intelligent carbon fiber metal composite laminate.

[0025] The hot pressing process utilizes a specialized mold equipped with an optical fiber positioning structure. The hot pressing preparation process involves placing the mold, already filled with laminates, into a vacuum bag, which is then placed into an autoclave. The autoclave's temperature is controlled by the autoclave program. The mold is heated to 240°C at a rate of 5°C / min and held for 10 minutes. The pressure is then increased at 0.02MPa / min to 0.2MPa, at which point the resin becomes viscous. Air is expelled under pressure, and the optical fiber sensor 6 is bonded to the printed substrate, the printed sub-substrate itself, and the printed substrate and aluminum plate. The mold is then cooled to 40°C at a rate of 5°C / min, with pressure maintained throughout the cooling process. Once the temperature reaches 40°C, the temperature is maintained for 10 minutes, and the pressure is reduced to 0MPa at a rate of 0.1MPa / min.

[0026] In another embodiment, if Figure 2 As shown, the intelligent carbon fiber metal composite laminate prepared according to the above method has a structure comprising: an upper metal plate 1, an upper substrate 2 (filled with continuous carbon fibers inside), a lower substrate 3 (filled with continuous carbon fibers inside), and a lower metal plate 4; wherein, between the upper substrate 2 and the lower substrate 3 are: a three-dimensional hole groove 5, an optical fiber sensor 6 (red represents an optical fiber), a positioning pin 7, and a positioning hole 8.

[0027] The embedded optical fiber sensor 6 enables the intelligent carbon fiber metal composite laminate to sense the strain on the laminate and its own temperature change, thereby realizing overall state monitoring of the laminate.

[0028] The solution in the above embodiment has the following beneficial effects: (1) By 3D printing a continuous carbon fiber matrix with pre-reserved holes and grooves, the optical fiber sensor 6 can be arranged three-dimensionally inside the laminate, and the sensor layout can be freely designed according to needs, thereby significantly improving the perception flexibility and monitoring accuracy.

[0029] (2) Since the positioning holes 8 and positioning pins 7 are directly formed on the printed substrate, the holes and grooves can be accurately aligned during the mold closing process, which not only ensures the bonding strength between the optical fiber sensor 6 and the substrate, but also avoids the problem of sensor offset or breakage in the traditional embedding process, thereby improving the structural reliability; (3) The 3D printing matrix is ​​treated by hot pressing process, which effectively eliminates the defects such as gaps and uneven interlayer bonding generated during the printing process, improves the density and mechanical properties of the matrix, and at the same time enhances the interface bonding strength between metal and composite materials, so that the overall laminate has both excellent mechanical properties and long-term service stability.

[0030] Therefore, the present invention not only realizes the flexible manufacturing and precise monitoring of intelligent carbon fiber metal laminates, but also significantly improves their structural integrity and durability, making them suitable for high-performance demanding fields such as aerospace, automobiles, etc.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an intelligent carbon fiber metal laminate, characterized in that: The following steps are involved: A thermoplastic 3D printed sub-matrix with pre-reserved holes and grooves is printed using a continuous carbon fiber 3D printer; the pre-reserved holes and grooves are arranged in a three-dimensional space and are adapted to the parameters of the optical fiber sensor (6); Embedding the optical fiber sensor (6) into the reserved hole groove of the thermoplastic 3D printing sub-matrix and closing the mold; Surface treatment of metal sheets; Place the processed metal plate and the printed substrate after mold closing in the mold according to the set layering method; The laminate is subjected to hot pressing and curing to obtain an intelligent carbon fiber metal composite laminate capable of sensing the strain exerted on the laminate and the change in its own temperature.

2. The method for preparing the intelligent carbon fiber metal composite laminate according to claim 1, characterized in that: The thermoplastic 3D printing sub-base is a split structure, comprising an upper base (2) and a lower base (3), and both the upper base (2) and the lower base (3) are provided with a partial hole groove structure.

3. The method for preparing the intelligent carbon fiber metal composite laminate according to claim 1, characterized in that: The diameter of the holes and grooves formed after the thermoplastic 3D printed sub-matrix is ​​molded matches the diameter of the optical fiber sensor (6).

4. The method for preparing the intelligent carbon fiber metal composite laminate according to claim 1, characterized in that: The optical fiber sensor (6) is embedded in the hole groove without the need for adhesive.

5. The method for preparing the intelligent carbon fiber metal composite laminate according to claim 1, characterized in that: The thermoplastic 3D printing sub-base is provided with a positioning hole (8) and a positioning pin (7).

6. The method for preparing the intelligent carbon fiber metal composite laminate according to claim 1, characterized in that: The hot pressing process uses a mold provided with an optical fiber positioning structure.

7. The method for preparing the intelligent carbon fiber metal composite laminate according to claim 1, characterized in that: The metal plate surface treatment includes chemical cleaning and anodizing.

8. The method for preparing the intelligent carbon fiber metal composite laminate according to any one of claims 1 to 7, characterized in that: The hot pressing molding process includes: placing the mold with the laminate in it into a vacuum bag, placing the vacuum bag into an autoclave, and controlling the temperature in the autoclave through the autoclave program; the temperature control process is as follows: heating to 240°C at a heating rate of 5°C / min and keeping it warm for 10 minutes, then increasing the pressure to 0.2MPa at 0.02MPa / min, at which time the resin becomes viscous at this temperature, and under the action of pressure, the air is expelled and the optical fiber sensor (6) is combined with the printing substrate, the printing sub-substrate itself, and the printing substrate and the metal plate, and then cooling to 40°C at 5°C / min, maintaining the pressure during the cooling process, and when it drops to 40°C, keeping it warm for 10 minutes and reducing the pressure to 0MPa at a rate of 0.1MPa / min.

9. An intelligent carbon fiber metal composite laminate prepared according to the method according to any one of claims 1 to 8.

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