CN108045002A - A kind of honeycomb sandwich construction and preparation method thereof - Google Patents

Abstract

The invention discloses a kind of honeycomb sandwich construction and preparation method thereof, which includes：One layer of sticky object is coated with respectively in honeycomb core material upper and lower surface；One layer of prepreg is coated with respectively in the honeycomb core material upper and lower surface for being coated with sticky object；Vacuum Package is carried out to the honeycomb core material for being coated with prepreg, and is cured at one atm, obtains pretreated honeycomb core material；Vacuum Package is carried out to pretreated honeycomb core material, and carries out curing molding, obtains honeycomb sandwich construction.The present invention is of low cost, and can avoid collapsing for cellular material.

Description

A kind of honeycomb sandwich structure and preparation method thereof

technical field

The invention belongs to the technical field of material forming, and in particular relates to a preparation method of a honeycomb sandwich structure and a honeycomb sandwich structure prepared by the preparation method.

Background technique

The honeycomb sandwich structure is a layered structure composed of a skin and a honeycomb core material. It has the advantages of light weight, good strength and rigidity, impact resistance, and fatigue resistance. It is also one of the structural forms with the highest structural efficiency in aircraft structures. Common honeycomb core materials include aluminum honeycomb, Nomex honeycomb, etc. Honeycomb sandwich structure is widely used in aircraft wing leading edge, rudder, flap, aileron and other parts.

At present, in the field of aviation, the preparation method of the honeycomb sandwich structure is mainly to lay the prepreg on the pre-processed honeycomb structure on the mold, and use the adhesive film to realize the bonding, and then seal the vacuum bag and place it in the autoclave. Curing and forming.

The vacuum infusion molding process in the liquid molding technology of composite materials is often used to prepare laminated boards and foam sandwich structures. However, the honeycomb is a multi-porous material, and the conventional process method will flow into the honeycomb cells when the resin is injected, and it is difficult to remove a large amount of gas in the honeycomb cells under vacuum conditions, and the gas easily enters the skin panel to form pores.

Contents of the invention

(1) Purpose of the invention

The object of the present invention is to provide a method for preparing a honeycomb sandwich structure capable of avoiding the collapse of the manufactured honeycomb material and the honeycomb sandwich structure prepared by the preparation method.

(2) Technical solutions

In order to solve the above problems, the first aspect of the present invention provides a method for preparing a honeycomb sandwich structure, comprising: covering the upper surface, lower surface and surroundings of the honeycomb core material with a layer of adhesive; The upper surface, the lower surface and the surrounding of the honeycomb core material of the object are respectively covered with a layer of prepreg material; the honeycomb core material coated with prepreg material is vacuum packaged and cured under an atmospheric pressure to obtain the pretreated honeycomb Core material: vacuum-encapsulate the pretreated honeycomb core material, and perform curing molding to obtain a honeycomb sandwich structure.

Further, after laying the prepreg and before vacuum encapsulation, the preparation method further includes: laying a rough layer on the upper and lower surfaces of the honeycomb core covered with the prepreg; The honeycomb core material with the rough layer is vacuum-packed and cured to obtain the pretreated honeycomb core material.

Further, the step of paving a rough layer on the upper surface and the lower surface of the prepreg-coated honeycomb core material respectively includes: paving the upper surface and the lower surface of the prepreg-coated honeycomb core material respectively. A release layer is covered; a breathable layer is respectively laid on the upper surface and the lower surface of the honeycomb core material covered with the release layer.

Further, the adhesive is the same type of resin system as the skin panel material.

Further, the prepreg and the skin panel material are the same kind of resin system.

Further, the preparation method further includes: when there are bare cells in the pretreated honeycomb core material, adding a prepreg at the position of the exposed cells and performing secondary curing.

Further, the step of encapsulating the pretreated honeycomb core material according to the vacuum infusion or vacuum introduction process includes: respectively laying a reinforcing fiber on the upper and lower surfaces of the pretreated honeycomb core material; A release material layer is laid on the upper and lower surfaces of the honeycomb core material respectively; an anti-adhesive material layer is respectively laid on the upper and lower surfaces of the honeycomb core material with the release material layer laid; A diversion device is placed on the upper and lower surfaces of the honeycomb core material of the substance layer; the honeycomb core material with the diversion device is vacuum-packed with two layers of vacuum bags, and a glue injection port is set on the inner vacuum bag and glue outlet.

Further, after the vacuum encapsulation, it also includes: vacuuming the two-layer vacuum bag and keeping it for a predetermined time; injecting glue through the glue injection port to the guide device; when resin appears at the glue outlet, stop the glue injection, and vacuum Continue vacuuming the bag; solidify the vacuum-encapsulated honeycomb core material at the solidification temperature and heating and cooling rate set based on the material system; cool the honeycomb core material after solidification treatment, and detach the cooled honeycomb core material mold to obtain a honeycomb core material.

Further, the adhesive, prepreg and skin panel are materials at the same curing temperature level.

According to another aspect of the present invention, a honeycomb sandwich structure prepared according to a method for preparing a honeycomb sandwich structure is provided.

(3) Beneficial effects

The technical solution of the present invention has the following beneficial technical effects:

1. The honeycomb sandwich structure is prepared by liquid forming technology, which reduces the manufacturing cost, and because it is formed under an atmospheric pressure, the collapse of the honeycomb material is avoided;

2. It solves the problem that the resin is easy to flow and the glue is filled into the honeycomb cells in the traditional vacuum introduction process, and the skin panel is easy to have pores. Prepreg is used to process the honeycomb core material to block the pores of the honeycomb core material, so as to prevent the resin from entering the honeycomb cells when the vacuum is introduced. The pretreated honeycomb will make the resin along the dry fiber when the vacuum is introduced. Flow in the same direction without flowing into the honeycomb cells, forming a strong bonding interface between the skin panel and the core material.

3. Due to the use of commercial prepreg and adhesive film materials (adhesives), the quality of the pretreated honeycomb is stable and reliable.

4. Wet peelable cloth and air felt are used to make the upper and lower surfaces of the cured honeycomb form a rough interface that is easy to bond, so that the introduced resin forms a good bonding interface with the treated upper and lower surfaces of the honeycomb.

5. The use of prepreg and adhesive film achieves a good bonding interface between the skin panel and the honeycomb core material.

Description of drawings

Fig. 1 is the flow chart of the preparation method of a kind of honeycomb sandwich structure of the embodiment of the present invention;

Fig. 2 is the flowchart of the preparation method of a kind of honeycomb sandwich structure of the embodiment of the present invention;

Fig. 3 is the flowchart of the preparation method of a kind of honeycomb sandwich structure of embodiment three of the present invention;

Fig. 4 is the flowchart of the preparation method of a kind of honeycomb sandwich structure of embodiment four of the present invention;

Fig. 5 is the flowchart of the preparation method of a kind of honeycomb sandwich structure of embodiment five of the present invention;

6 is a flowchart of a method for preparing a honeycomb sandwich structure according to Embodiment 6 of the present invention;

Fig. 7 is the schematic diagram of honeycomb core material pretreatment process;

Fig. 8 is the schematic diagram of the honeycomb core material obtained after curing;

Fig. 9 is a schematic diagram of the process of preparing a honeycomb sandwich structure using a liquid forming process.

Reference signs:

1. Honeycomb core material, 1-0. Honeycomb core material after pretreatment, 2. Adhesive film, 3. Prepreg, 4. Wet peelable cloth, 5. Air felt, 6. Mold, 7. Vacuum bag, 8. Reinforcing fiber, 9. Release cloth, 10. Tetrafluoro cloth, 11. Drainage net.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in combination with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are exemplary only, and are not intended to limit the scope of the present invention. Also, in the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily obscuring the concept of the present invention.

The present invention adopts the composite material liquid molding process to prepare the honeycomb sandwich structure, wherein, before preparing the honeycomb sandwich structure, it is necessary to prepare the honeycomb core material in advance, because the skin panel material of the honeycomb core material selected in the present invention is mainly composed of resin and reinforced Composed of fibers, the resins include epoxy resin, double horse resin, benzoxazine resin, etc., and the reinforcing fibers include carbon fiber, glass fiber, aramid fiber, etc. Therefore, the honeycomb core material can choose aluminum honeycomb, Nomax honeycomb, Kevlar honeycomb, etc., for example: HRH-10, CR-PAA Core and other honeycomb core materials of Hexcel Company.

Fig. 1 is a flowchart of a method for preparing a honeycomb sandwich structure according to Embodiment 1 of the present invention.

As shown in Figure 1, the preparation method includes the following steps S101-S104:

S101, laying a layer of adhesive 2 on the upper surface, lower surface and surroundings of the honeycomb core material 1;

Specifically, the adhesive can be an adhesive film. Since both the skin panel material of the honeycomb core material and the adhesive film are made of resin, in order to ensure the compatibility between the resins, the material of the adhesive should be selected to be compatible with the honeycomb core material. The resin material of the skin panel is the adhesive film and prepreg of the same resin system, and the material with the same curing temperature level is selected, such as low temperature curing material, medium temperature curing material or high temperature curing material; optionally, the adhesive film material can be Henkel The company's HYSOL EA 9628, PL7000, METLBOND 1515, etc.

S102, laying a layer of prepreg 3 on the upper surface, lower surface and surroundings of the honeycomb core material covered with the adhesive;

Specifically, a layer of prepreg is laid on the upper, lower and surrounding surfaces of the honeycomb core material after the adhesive is applied, and the order of the adhesive and the prepreg is from the inside to the outside.

Optionally, the prepreg can be commercial CYCOM 970, CYCOM977, CYCOM 7701 or Loctite BZ9704, etc.

S103, vacuum-encapsulating the honeycomb core material coated with the prepreg 3, and curing it under an atmospheric pressure to obtain a pretreated honeycomb core material;

Among them, vacuum packaging is mainly realized by vacuum bags.

S104, vacuum-encapsulate the pretreated honeycomb core material, and perform curing molding to obtain a honeycomb sandwich structure.

Specifically, the pretreated honeycomb core material is vacuum-packaged according to a composite material liquid forming process; preferably, the liquid forming process can adopt a vacuum infusion process.

In Embodiment 1 of the present invention, pretreatment is performed on the honeycomb core material (ie steps S101 and S102 ), so that the pretreated honeycomb core material can be well bonded to the prepreg covering the upper and lower surfaces. Prepregs and adhesives are commercially available prepregs and adhesive film materials respectively. Due to the strong operability of the honeycomb pretreatment process and the vacuum introduction process, the quality of the pretreated honeycomb is stable and reliable. The use of prepreg and adhesive film achieves a good bonding interface between the skin panel and the honeycomb. In the present invention, the skin panel refers to the layered structure formed on the upper and lower surfaces of the honeycomb core material after vacuum introduction.

Fig. 2 is a flowchart of a method for preparing a honeycomb sandwich structure according to Embodiment 2 of the present invention.

As shown in Figure 2, the second embodiment of the present invention adds step S201-step S202 after step S102 of the first embodiment of the present invention, which includes:

S201, laying a rough layer with a rough surface on the upper surface, the lower surface and the periphery of the honeycomb core material covered with the prepreg 3;

On the one hand, the purpose of the rough layer is to facilitate demoulding and ventilation, and on the other hand, it is also to form a rough surface on the upper and lower surfaces, which is conducive to bonding with the skin panel.

S202, vacuum-encapsulating and curing the honeycomb core material coated with the rough layer to obtain a pretreated honeycomb core material.

Specifically, after vacuum encapsulation, the paved honeycomb core material is put into a curing furnace for curing, and the solidified honeycomb core material is cooled and demolded after curing. If resin overflows around the honeycomb core material after curing, the cured honeycomb core material can be processed by manual trimming.

In Embodiment 1 of the present invention, further pretreatment is performed on the honeycomb core material, so that the pretreated honeycomb core material can achieve further good bonding with the prepreg material covered on the upper and lower surfaces.

Fig. 3 is a flowchart of a method for preparing a honeycomb sandwich structure according to Embodiment 3 of the present invention.

As shown in Figure 3, Embodiment 3 of the present invention is a sub-step of step S201 in Embodiment 2, which includes:

S2011, laying a release layer 4 on the upper and lower surfaces of the prepreg-coated honeycomb core material;

S2012, respectively laying a breathable layer 5 on the upper surface and the lower surface of the honeycomb core material covered with the release layer 4 .

The release layer 4 can be a wet-peelable cloth, and the air-permeable layer can be an air-felt. When the release layer is a wet-peelable cloth and the air-permeable layer is an air-felt, step S2021 is specifically: The upper surface and the lower surface of the material are respectively covered with a layer of wet peelable cloth;

Step S2022 is specifically: spreading a layer of air felt on the upper surface and the lower surface of the honeycomb core material covered with wet peelable cloth.

Among them, the purpose of covering wet peelable cloth and air felt is to facilitate demoulding and ventilation on the one hand, and on the other hand to form a rough surface on the upper and lower surfaces, which is conducive to bonding with the skin panel. Optionally, commercial wet-peelable cloth can be used, and commercial wet-peelable cloth materials can be selected from Airtech’s Release Ply series of peelable cloth, Hexcel’s wet-peelable cloth M21/48%/F08111 and F161/43%/F08111, Henkel's EA9895WPP (high temperature) and EA9896 (medium temperature), and Cytec's CYCOM7701/52006, etc.; the use of wet peelable cloth and air felt enables the upper and lower surfaces of the cured honeycomb core material to form Easy-to-adhesive rough interface, so that the imported resin forms a good bonding interface with the upper and lower surfaces of the processed honeycomb.

Fig. 4 is a flowchart of a method for preparing a honeycomb sandwich structure according to Embodiment 4 of the present invention.

As shown in Figure 4, Embodiment 4 of the present invention is based on Embodiment 1, and further includes the following step S105:

S105, when there are bare cells in the pretreated honeycomb core material, adding prepreg at the positions of the exposed cells and performing secondary curing.

Specifically, the secondary curing is also carried out under one atmospheric pressure, and after the curing is completed, it still needs to be cooled and demolded.

Fig. 5 is a flowchart of a method for preparing a honeycomb sandwich structure according to Embodiment 5 of the present invention.

Specifically, the honeycomb core material that has been released from the mold after curing is sealed and placed on the mold, and then dry fibers, such as carbon fibers and glass fibers, are laid on the upper and lower surfaces by manual or automatic laying. , Aramid fiber, etc. After packaging according to the process of vacuum infusion or vacuum introduction, the processes of vacuuming, glue injection, curing and molding are completed.

As shown in Figure 5, the fifth embodiment of the present invention is implemented after step S105 of the fourth embodiment, including the following steps S501-S505:

S501, respectively laying a reinforcing fiber on the upper and lower surfaces of the honeycomb core material obtained after curing;

S502, respectively laying a release material layer on the upper and lower surfaces of the honeycomb core material laid with reinforcing fibers;

Wherein, the release material layer can adopt a release cloth.

S503, laying an anti-adhesive substance layer on the upper and lower surfaces of the honeycomb core material on which the release substance layer is laid;

The anti-adhesive substance layer can adopt tetrafluorocloth.

S504, respectively laying a diversion device on the upper and lower surfaces of the honeycomb core material on which the anti-adhesive material layer is laid;

Wherein, the diversion device may adopt a diversion net.

S505, vacuum-encapsulate the honeycomb core material with the diversion device in two layers of vacuum bags, and set the glue injection port and the glue outlet on the inner vacuum bag, the glue outlet should be below the inner vacuum bag, Vacuum packaging can be done by using a vacuum bag to seal it on the mold.

As shown in Figure 6, the sixth embodiment of the present invention is implemented after the vacuum packaging step of the fifth embodiment, including the following steps S601-S606:

S601, vacuumize the airtight space between the two layers of vacuum bags for a predetermined time;

Specifically, vacuumize the space between the two layers of vacuum bags and keep it for 12 hours to ensure that there is no air leakage in the vacuum packaging.

S602, injecting glue into the guide net through the glue injection port;

Specifically, the glue injection port is connected with the glue injection pipe, and the glue injection pipe is connected with the resin tank, so that the fluid can be input to the glue injection port through the glue injection pipe, and then from the upper surface of the honeycomb core material along the flow guide net, PTFE cloth, and mold release cloth. The layer penetrates down to the deflector mesh on the lower surface.

S603, when the resin appears at the glue outlet, stop the glue injection, and continue to evacuate the airtight space between the two layers of vacuum bags;

S604, curing the vacuum-encapsulated honeycomb core material at the curing temperature and the heating and cooling rates set based on the material system;

S605, cooling the solidified honeycomb core material;

Specifically, it is cooled with the furnace.

S606, demoulding the cooled honeycomb core material to obtain the honeycomb core material. The present invention pretreats the honeycomb core material by using prepreg and adhesives, and adds wet peelable cloth and air felt during the honeycomb core material treatment process to form a rough surface that is easy to bond, and then adopts a liquid forming process Prepare the honeycomb sandwich structure. The liquid forming process can not only reduce the manufacturing cost, but also avoid the collapse of the honeycomb material because it is formed under one atmospheric pressure. Pre-treatment of the honeycomb core blocks the cells, thus avoiding starvation of the skin panels due to resin inflow. At the same time, it solves the problem that the resin is easy to flow and the glue is filled into the honeycomb cells in the traditional vacuum introduction process, and the skin panel is easy to have pores.

The mode of the above-mentioned embodiment of the present invention is described in detail below by giving examples, and its technical process can be divided into three major steps:

Step 1: As shown in Figure 7, firstly, the upper and lower surfaces of the honeycomb core material 1 are sequentially covered with adhesive film 2, prepreg 3, wet peelable cloth 4 and air felt 5, and the pretreatment is completed so far, and then Place the pretreated honeycomb core material 1-0 on the mold 6, and then cover it with a vacuum bag 7 for sealing.

Step 2: After sealing, put it into a curing furnace for curing, and then cool and demould after curing to obtain a honeycomb core material 1-0 as shown in FIG. 8 .

Step 3: As shown in Figure 9, the upper and lower surfaces of the demoulded honeycomb core material 1-0 are respectively covered with reinforcing fibers 8, release cloth 9, tetrafluoro cloth 10 and flow guide net from the inside to the outside. 11, and then adopt vacuum bag 5 to seal it on the mould.

The honeycomb sandwich structure prepared by the preparation method of the present invention can be cemented with composite materials, and can also be cemented with metals to form a strong bonding interface.

It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and not to limit the present invention. Therefore, any modification, equivalent replacement, improvement, etc. made without departing from the spirit and scope of the present invention shall fall within the protection scope of the present invention. Furthermore, it is intended that the appended claims of the present invention cover all changes and modifications that come within the scope and metespan of the appended claims, or equivalents of such scope and metesight.

Claims (10)

1. a kind of preparation method of honeycomb sandwich construction, which is characterized in that including：

One layer of sticky object is coated in honeycomb core material upper surface, lower surface and surrounding；

One layer of prepreg is coated with respectively in the honeycomb core material upper surface, lower surface and the surrounding for being coated with the sticky object；

Vacuum Package is carried out to the honeycomb core material for being coated with the prepreg, and is cured at one atm, is obtained To pretreated honeycomb core material；

Vacuum Package is carried out to the pretreated honeycomb core material, and carries out curing molding, obtains honeycomb sandwich construction.

2. the preparation method of a kind of honeycomb sandwich construction according to claim 1, which is characterized in that be coated with the preimpregnation After material and before progress Vacuum Package, the preparation method further includes：

A shaggy rough layer is coated with respectively in the honeycomb core material upper and lower surface for being coated with the prepreg；

Vacuum Package is carried out to the honeycomb core material for being coated with the rough layer, and is cured, obtains pretreated bee Nest core.

3. the preparation method of a kind of honeycomb sandwich construction according to claim 2, which is characterized in that described pre- being coated with The step of honeycomb core material upper and lower surface of leaching material is coated with a shaggy rough layer respectively includes：

A release layer is coated with respectively in the honeycomb core material upper and lower surface for being coated with the prepreg；

An air-permeable layer is coated with respectively in the honeycomb core material upper and lower surface for being coated with the release layer.

4. the preparation method of a kind of honeycomb sandwich construction according to claim 1, which is characterized in that the sticky object is with covering Surface plate material is one species resin system.

5. the preparation method of a kind of honeycomb sandwich construction according to claim 1, which is characterized in that the prepreg is with covering Surface plate material is one species resin system.

A kind of 6. preparation method of honeycomb sandwich construction according to claim 4 or 5, which is characterized in that the preparation side Method further includes：

When the pretreated honeycomb core material is there are during exposed cell, in the position of the exposed cell, addition prepreg is gone forward side by side Row secondary curing.

7. the preparation method of a kind of honeycomb sandwich construction according to claim 1, which is characterized in that after the pretreatment Honeycomb core material the step of being packaged according to priming by vacuum or vacuum introducing technology include：

Upper and lower surface difference one reinforcing fiber of placed of the honeycomb core material obtained after hardening；

In placed, the upper and lower surface difference placed one of the honeycomb core material of the reinforcing fiber demoulds material layer；

The upper and lower surface difference placed primary antibody adhesive material layer of the honeycomb core material of the demoulding material layer in placed；

Upper and lower surface difference placed one guiding device of the honeycomb core material of the anti-stick material layer in placed；

By placed, the honeycomb core material of the guiding device carries out Vacuum Package using two layers of vacuum bag, and in internal layer vacuum Gum-injecting port and gum outlet are set on bag.

8. the preparation method of a kind of honeycomb sandwich construction according to claim 7, which is characterized in that carrying out Vacuum Package Afterwards, further include：

Confined space between two layers of vacuum bag is vacuumized, is kept for the predetermined time；

By gum-injecting port to the guiding device injecting glue；

When occurring resin at gum outlet, stop injecting glue, the confined space between two layers of vacuum bag is continued to vacuumize；

In the solidification temperature and heating, cooling rate set based on material system, the honeycomb core material of Vacuum Package is cured；

The honeycomb core material after curing process is cooled down；

The honeycomb core material after cooling is demoulded, obtains honeycomb core material.

9. the preparation method of a kind of honeycomb sandwich construction according to claim 1, which is characterized in that the sticky object, institute State the material of prepreg and skin panel for identical solidification temperature level.

10. honeycomb prepared by a kind of a kind of preparation method of honeycomb sandwich construction according to any one of claim 1-9 Sandwich.