CN112223804B

CN112223804B - Method for forming and preparing laminated composite material honeycomb

Info

Publication number: CN112223804B
Application number: CN202011018291.9A
Authority: CN
Inventors: 吴林志; 陈晓健; 于国财; 林壮; 初子祺
Original assignee: Harbin Engineering University
Current assignee: Harbin Engineering University
Priority date: 2020-09-24
Filing date: 2020-09-24
Publication date: 2021-09-17
Anticipated expiration: 2040-09-24
Also published as: CN112223804A

Abstract

The invention discloses a forming preparation method of a laminated composite material honeycomb, which relates to the field of materials and aims to solve the problems that the forming quality of the existing laminated composite material honeycomb is low, the designability of the structure size is not strong, and manual operation cannot be separated. The composite material honeycomb prepared by the method has high forming quality, strong designability of structure size, simple and feasible preparation method, manual operation separation, independent preparation by a machine and full-automatic production conditions. The method is applied to the field of preparation of composite material honeycomb structures.

Description

Method for forming and preparing laminated composite material honeycomb

Technical Field

The invention relates to the field of materials, in particular to a forming preparation method of a laminated composite material honeycomb.

Background

Inspired by the natural honeycomb structure, humans have made honeycomb structures. The honeycomb structure has great advantages in topological configuration, large internal space, low occupation ratio of the bearing structure and the like, and is a light high-bearing structure. However, the in-plane and bending mechanical properties of the honeycomb structure are poor, and in order to improve the properties, the honeycomb and the panel are combined to be made into a honeycomb sandwich structure. On the basis of keeping the original axial bearing capacity unchanged, the mechanical properties of the integral structure, such as in-plane compression, bending resistance, torsion resistance, shear resistance and the like, are greatly improved.

With the continuous development of material technology, the appearance of new materials, particularly composite materials, greatly improves the mechanical property of the honeycomb structure. The honeycomb structure made of traditional metal materials mainly comprises aluminum honeycomb, stainless steel honeycomb, copper honeycomb, nickel alloy honeycomb and the like. The composite material honeycomb structure mainly comprises aramid fiber honeycombs, glass fiber honeycombs, carbon fiber honeycombs and the like, wherein the aramid fiber honeycombs have the advantages of light weight, easiness in forming, low cost and the like, so that the aramid fiber honeycombs are widely applied to the field of aerospace vehicles, but the mechanical properties of the aramid fiber honeycombs are not strong; the high-performance composite material honeycomb structure such as carbon fiber is expected to be applied to more fields and play a greater role due to excellent mechanical properties such as light weight, high strength and high rigidity. Compared with the honeycomb structure prepared from the woven composite material, the laminated composite material has the advantages that the compression performance is more excellent, the material is thinner, the cell wall of the prepared honeycomb structure is thinner, the structure density is lower, the out-of-plane compression strength is higher, and the mechanical property is more excellent. But the problems of low production efficiency, poor finished product quality and the like exist in the honeycomb structure of the high-performance laminated composite material such as carbon fiber and the like, and the application of the honeycomb structure in engineering is limited.

The current batch preparation method of the honeycomb structure mainly comprises the following three methods:

(1) a honeycomb structure having a certain toughness for a honeycomb base material with a low density, for example: the low-density aluminium honeycomb structure is made up by coating adhesive on the surface of metal foil, stacking many cut metal foils, inserting several pins into two sections after the adhesive is solidified, and finally stretching the pins by machine. The method has the advantages that the preparation efficiency is high, the defects that only a honeycomb structure with low density can be prepared, the shape of each unit cell is difficult to ensure, and the quality is not uniform.

(2) A honeycomb structure having a certain toughness for a honeycomb base material with a high density, for example: the high-density aluminium honeycomb structure is generally formed by a method of firstly stamping and then bonding, namely, a machine is used for folding metal into a corrugated plate shape, the stamping method is generally adopted, then an adhesive is coated on the surface of the corrugated plate, and finally the corrugated plate is buckled to form a honeycomb structure. The method has the advantages that a high-density honeycomb structure can be prepared, the product quality is high, and the defects of low efficiency, long whole preparation period and high cost are overcome.

(3) Aiming at honeycomb parent materials with poor toughness, such as aramid fiber honeycombs, the parent materials with poor toughness and difficult punch forming are generally cut into required sizes by fiber materials which are not soaked with resin, then adhesive is coated on the surfaces of the materials, a machine is used for stretching and preforming after curing, finally the materials are soaked with resin, cured and finally shaped. The method has the advantages that the honeycomb structure can be prepared from the composite material with poor toughness, and the defects that the efficiency is low, the whole preparation period is long, the preparation process is complex, and the cost is increased are overcome.

By way of illustration, the above methods for industrially preparing the honeycomb structure are not suitable for batch production of novel laminated composite materials, firstly, the laminated composite materials have no toughness, and the composite materials are easy to break and lose bearing capacity due to direct stretching or punch forming, secondly, the method of stretching and then infiltrating resin has great influence on the overall performance of the composite materials, and the mechanical properties of the laminated composite materials are difficult to be fully exerted by the method of infiltrating resin at the later stage and curing without pressure.

The preparation process of the composite material honeycomb structure comprises the following steps: 3D printing method, resin transfer molding method, interlocking preparation process and the like, but the methods are not suitable for mass production and use in engineering because of high preparation cost. Therefore, a new method for manufacturing a honeycomb structure of a laminated composite material with mature technology, reliable quality, mass production and low cost is needed.

Disclosure of Invention

The invention aims to solve the problems that the existing laminated composite material honeycomb is low in molding quality, low in designability of structure size and incapable of being separated from manual operation, and provides a preparation method of the laminated composite material honeycomb with reliable quality and better performance. The laminated composite material honeycomb prepared by the method has high forming quality, strong designability of structure size, simple and feasible preparation method, manual operation separation, independent preparation by a machine and full-automatic production conditions.

The invention discloses a forming preparation method of a laminated composite material honeycomb, which comprises the following steps:

1) pretreatment of materials:

treating the surface of the metal foil material to remove stains and oxide films on the surface of the metal foil material;

2) cutting and arranging materials:

cutting the metal foil material and the prepreg processed in the last step according to the designed size, and paving the metal foil material and the prepreg into a single-layer board according to the sequence of the prepreg/the metal foil/the prepreg;

3) preparing a multilayer board: laying strip-shaped isolation layers on the surfaces of the single-layer boards, and laying a plurality of single-layer boards together according to a pre-laying scheme to form a multi-layer board;

4) curing the multilayer board: placing two steel plates on the upper part and the lower part of the laid multilayer board, and solidifying the multilayer board by adopting an autoclave or vacuum auxiliary forming process;

5) fixing the multilayer board: after the multilayer board is cured, removing the steel plates on the two sides, and placing the multilayer board on a composite material honeycomb stretch forming device;

the composite material honeycomb stretching forming device comprises two cylinders and a plurality of plates which are respectively sleeved on the cylinders; one side wall of the plate is respectively arranged corresponding to the isolation layers on the upper side and the lower side of the multilayer plate, the thickness of the plate is consistent with the width of the isolation layers, the length of the side wall is more than or equal to that of the isolation layers, and the diameter D2 of the cylinder is 0.3-0.7 of the width D1 of the top of the plate;

6) stretching of the multilayer board: and (3) directly stretching the two ends of the two cylinders by using a machine, stretching the multilayer board, and obtaining the composite material honeycomb structure after stretch forming.

The scheme in the step 3) is that if the cell walls of the honeycomb cells are designed in advance, the width of the non-bonded cell walls is h1, and the width of the bonded cell walls is h2, the width of the isolation layers is h2+2 × h1, and the isolation layers are arranged at intervals of h 2.

Further, the metal foil material is an aluminum alloy foil.

Further, the metal foil material is an aluminum alloy foil, and the surface of the metal foil is treated by a phosphoric acid anodizing method.

Further, the thickness of the metal foil layer in step 2) is less than 30 microns.

Furthermore, strip-shaped isolation layers are laid on the surfaces of the single-layer plates in the step 3), the adjacent single-layer plates are arranged in a buckling mode, and only one isolation layer is needed between the two single-layer plates.

The opposite buckle is placed to prevent the following situations from occurring: if the single-layer board is asymmetrically laid, the single-layer board with two asymmetrically laid layers can be integrally asymmetrically laid if being normally laid, so that the bonded part is bent, the structural performance is influenced, and the buckling laid layers are adopted to avoid the above situation.

Further, the step 4) of curing the multilayer board by using the autoclave molding process is performed by the following steps: wrapping a layer of breathable felt on the periphery of the multilayer board, putting the multilayer board into a sealing bag, vacuumizing the sealing bag, and putting the multilayer board into a hot-pressing tank for hot pressing; the hot pressing parameters are as follows: keeping the temperature at 80 ℃ for 30 minutes, and increasing the pressure to 0.1 MPa; and (3) preserving the heat at the temperature of 130 ℃ for 90 minutes, increasing the pressure to 0.3MPa, then cooling to room temperature, releasing the pressure, and finishing the curing process.

Further, the step 4) of curing the multilayer board by using the vacuum assisted molding process is performed by the following steps: wrap up in the one deck air felt around the multiply wood earlier, put into the sealed bag, put into the oven or heat the platform surface and heat the multiply wood after the evacuation, the heating parameter is: and (3) preserving heat for 30 minutes at 80 ℃, preserving heat for 90 minutes at 130 ℃, then cooling to room temperature, releasing pressure, and finishing the curing process.

For the quality of structure molding, the autoclave molding process is superior to the vacuum auxiliary molding technology, but the finished product volume of the vacuum auxiliary molding technology is not limited due to the fact that the autoclave is not limited, and the preparation process is more convenient.

Further, the cylinder and the plate are made of a material having a relatively large modulus of elasticity.

Further, the preparation material is steel alloy or titanium alloy.

Further, use the both ends of two cylinders of machine direct stretching to guarantee that the tensile force is unanimous, the material of cylinder be stainless steel.

The invention has the following beneficial effects:

in contrast to the out-of-plane compressive strength of currently common honeycomb structures. By adopting the scheme of the invention, under the condition of the same density, the strength of the carbon/aluminum honeycomb is 2-3 times that of other honeycombs. The honeycomb structure with higher strength under the condition of the same density or lower density under the condition of the same density can be obtained by the simple preparation process, and the future application prospect is wide.

Drawings

FIG. 1 is an illustration of a single ply and thickness;

FIG. 2 is an illustration of the laying of a multi-layer board and the intermediate insulation layer;

FIG. 3 is a schematic structural diagram of a composite honeycomb stretch-forming apparatus according to the present invention;

FIG. 4 is a graph of the out-of-plane compressive strength of an example honeycomb structure; wherein, A is an aluminum honeycomb, B is a carbon fiber woven honeycomb, C is a phenolic resin honeycomb, D is a quartz honeycomb, E is a glass fiber honeycomb, F is a "paper" honeycomb, and G is a honeycomb structure prepared in the examples.

Detailed Description

It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples for carrying out the invention, and that various changes in form and details may be made therein without departing from the spirit and scope of the invention in practice.

To make the objects, aspects and advantages of the embodiments of the present invention more apparent, the following detailed description clearly illustrates the spirit of the disclosure, and any person skilled in the art, after understanding the embodiments of the disclosure, may make changes and modifications to the technology taught by the disclosure without departing from the spirit and scope of the disclosure.

The exemplary embodiments of the present invention and the description thereof are provided to explain the present invention and not to limit the present invention.

Examples

The embodiment relates to a method for forming and preparing a laminated composite material honeycomb, which comprises the following steps:

(1) pretreatment of materials: the surface of the metal foil material is treated to remove stains and oxide films on the surface of the metal foil material, so that the surface roughness is increased, the surface contact area is enlarged, the surface polarity is increased, and the surface bonding strength is improved.

The selected metal foil material is an aluminum alloy foil, and the surface of the metal foil is treated by a phosphoric acid anodizing method, so that the bonding strength of the metal foil and the composite material is improved. The bonding strength of the ductile metal foil material and the composite material is improved through the operation, and the phenomenon of layering between the materials during subsequent stretching is avoided.

(2) Cutting and arranging rules of materials: cutting the composite material prepreg and the metal foil material according to the size designed in advance, and paving the prepreg/the metal foil/the prepreg into a single-layer plate according to the sequence of the prepreg/the metal foil/the prepreg. The thickness of metal foil layer is less than 30 microns, and metal material is too thick leads to the structure wholeness ability not good easily, and practical application effect is relatively poor to metal material is too thick, is difficult for entering into the plasticity stage, can't play the effect of stereotyping. The prepreg is carbon fiber.

(3) Preparing a multilayer board: according to a pre-designed scheme, strip-shaped isolation layers are laid on the surfaces of the single-layer plates, the thinner the thickness is, the better the thickness is, and the influence on the curing of the single-layer plates can be reduced; the length is slightly longer than the width of the single-layer board, so that the single-layer board is prevented from standing together due to the overflow of the resin during curing; the width is cut according to the pre-designed size, and finally, a plurality of single-layer plates are stacked together. The width of a single cell wall is h1, the width of a double-layer wall is h2, the width of the isolation layer is h2+2 × h1, and the isolation layer is arranged at intervals of h 2; the first and second single layer panels should be placed in a snap-fit arrangement as shown in figure 2.

(4) Curing the multilayer board: and placing two steel plates on the upper part and the lower part of the laid multilayer board, and curing the multilayer board by adopting an autoclave molding process. Namely, wrapping a layer of breathable felt around the bag, putting the bag into a sealing bag, vacuumizing the bag and putting the bag into an autoclave. The autoclave parameters were: the temperature and the pressure in the tank are increased linearly, the temperature is kept for 30 minutes at 80 ℃, and the pressure is increased to 0.1 MPa; and (3) preserving the temperature for 90 minutes at 130 ℃, increasing the pressure to 0.3MPa, then cooling to room temperature, releasing the pressure, and finishing the curing process.

Or adopting a vacuum auxiliary forming technology, after the steps are vacuumized, putting the multilayer board into an oven or heating the surface of a heating table for heating, wherein the heating parameters are as follows: and (3) preserving heat for 30 minutes at 80 ℃, preserving heat for 90 minutes at 130 ℃, then cooling to room temperature, releasing pressure, and finishing the curing process. The autoclave molding quality is superior to that of the negative pressure molding technology, but the autoclave molding technology has volume limitation (the volume of a multilayer board depends on the volume of the autoclave), while the vacuum assisted molding technology has smaller limitation on the volume of the multilayer board, the preparation process is more convenient, and the cost is lower.

(5) Fixing the multilayer board: after the multilayer board is cured, taking out the multilayer board from the sealed bag, removing the steel plates on two sides, and placing the multilayer board in a composite honeycomb stretch forming device, as shown in fig. 3: the cylinder 1 and the plate 2 are prepared by recommending materials with larger elastic modulus, the plate 2 is bonded with the side surface of the multilayer board, the position corresponds to the isolation layer, the thickness is kept consistent with the width of the isolation layer and is h2, and the length can be larger than or equal to the width of the multilayer board; the plate 2 has a hole in the middle, and the size of the hole is consistent with that of the cylinder 1. The shape of the holes is preferably circular to facilitate the sliding of the plate 2 on the surface of the cylinder 1 and to eliminate the problem of stress concentration of the plate 2 during stretching. The diameter dimension D2 of the cylinder 1 is preferably 0.3-0.7 of the dimension D1 of the component 1, D1 being too small to be good, easily causing excessive bending of the sheet 2 during the stretching process, affecting the stretching quality and even breaking; too large a D1 results in a smaller effective bearing area of the steel block and is prone to large deformation.

(6) Stretching of the multilayer board: the honeycomb is stretched by directly stretching the ends of the cylinder 1 using a machine at as constant and slow a rate as possible, which tends to cause the upper honeycomb to stretch vigorously, resulting in delamination between the laminates. Because some metal materials have certain resilience characteristics, the resilience angle needs to be considered in the stretching process, namely the actual stretching angle is larger than the design angle.

Fig. 4 is a comparison of the out-of-plane compressive strength of the composite honeycomb structure (exemplified by a carbon/aluminum honeycomb) prepared by this example, as compared to the honeycomb structure currently available. The observation of the figure shows that under the condition of the same density, the strength of the carbon/aluminum honeycomb is 2-3 times that of other honeycombs. The honeycomb structure with higher strength under the same density condition or lower density under the same density condition can be obtained by the simple preparation process, and the future application prospect is wide.

Claims

1. A forming preparation method of a laminated composite material honeycomb is characterized by comprising the following steps:

1) pretreatment of materials:

2) cutting and arranging materials:

the composite material honeycomb stretch forming device comprises two cylinders (1) and a plurality of plates (2) which are respectively sleeved on the cylinders (1); one side wall of the plate (2) is respectively arranged corresponding to the isolation layers on the upper side and the lower side of the multilayer plate, the thickness of the plate (2) is consistent with the width of the isolation layers, the length of the side wall is more than or equal to that of the isolation layers, and the diameter D2 of the cylinder (1) is 0.3-0.7 of the width D1 of the top of the plate (2);

6) stretching of the multilayer board: directly stretching two ends of the two cylinders (1) by using a machine, stretching the multilayer board, and obtaining the composite material honeycomb structure after stretch forming; the metal foil material is an aluminum alloy foil, and the surface of the metal foil is treated by a phosphoric acid anodizing method; the thickness of the metal foil layer in the step 2) is less than 30 microns; and 3) paving strip-shaped isolation layers on the surfaces of the single-layer plates, wherein the adjacent single-layer plates are arranged in a buckling manner, and only one isolation layer is needed between the two single-layer plates.

2. The method of claim 1, wherein the spacer layer has a thickness of 0.005-0.02mm and a length longer than the width of the single-layer board.

3. The method for forming and preparing a honeycomb made of laminated composite material according to claim 1, wherein the step 4) of curing the multilayer board by autoclave forming process is performed by the following steps: wrapping a layer of breathable felt on the periphery of the multilayer board, putting the multilayer board into a sealing bag, vacuumizing the sealing bag, and putting the multilayer board into a hot-pressing tank for hot pressing; the hot pressing parameters are as follows: keeping the temperature at 80 ℃ for 30 minutes, and increasing the pressure to 0.1 MPa; and (3) preserving the heat at the temperature of 130 ℃ for 90 minutes, increasing the pressure to 0.3MPa, then cooling to room temperature, releasing the pressure, and finishing the curing process.

4. The method for forming and preparing a honeycomb made of laminated composite material according to claim 1, wherein the step 4) of curing the multilayer board by vacuum assisted forming process is performed by the following steps: wrap up in the one deck air felt around the multiply wood earlier, put into the sealed bag, put into the oven or heat the platform surface and heat the multiply wood after the evacuation, the heating parameter is: and (3) preserving heat for 30 minutes at 80 ℃, preserving heat for 90 minutes at 130 ℃, then cooling to room temperature, releasing pressure, and finishing the curing process.

5. The method for forming and preparing a honeycomb made of laminated composite material according to claim 1, wherein a machine is used to directly stretch the two ends of the two cylinders (1) and ensure the uniform stretching force, and the cylinders (1) are made of stainless steel.