阅读说明：本技术 一种大厚度蜂窝变形工艺方法 (Large-thickness honeycomb deformation process method ) 是由 郝磊 轩立新 贾顺利 杨茂伟 于 2021-07-30 设计创作，主要内容包括：本发明属于航空复合材料制造技术领域,一种大厚度蜂窝变形工艺方法,在大厚度蜂窝变形过程中,首先按照蜂窝夹层结构中蜂窝尺寸对蜂窝进行裁剪,然后采用抽真空方式对蜂窝进行缓慢加压,在加压后保持一定时间,然后再次进行加压过程,反复多次直至蜂窝变形到位后,采用压板对蜂窝进行施压,并保温一定时间,使蜂窝保持定型型面。本发明使蜂窝在变形过程中,能够有较为充分的时间调整蜂窝格空的变形能力,使蜂窝格空均匀变形,间接增加了蜂窝变形能力；本发明照蜂窝夹层结构蜂窝尺寸进行蜂窝裁剪,取消了蜂窝余量区对于蜂窝变形能力的限制,也增加了蜂窝变形能力,上述工艺措施的实施,解决了大厚度蜂窝变形问题。(The invention belongs to the technical field of aviation composite material manufacturing, and discloses a large-thickness honeycomb deformation process method. The invention can adjust the deformability of the honeycomb cells in a sufficient time in the deformation process of the honeycomb, so that the honeycomb cells are uniformly deformed, and the deformation capability of the honeycomb is indirectly increased; the honeycomb cutting method carries out honeycomb cutting according to the size of the honeycomb sandwich structure, cancels the limitation of a honeycomb allowance area on the deformation capacity of the honeycomb, and also increases the deformation capacity of the honeycomb.)

1. A large-thickness honeycomb deformation process method is characterized in that in the large-thickness honeycomb deformation process, firstly, the honeycomb is cut according to the size of the honeycomb in a honeycomb sandwich structure, then the honeycomb is slowly pressurized in a vacuumizing mode, the honeycomb is kept for a certain time after pressurization, then the pressurization process is carried out again, the honeycomb is pressurized by a pressing plate after repeated times until the honeycomb is deformed in place, and the heat is preserved for a certain time, so that the honeycomb keeps a shaped profile.

2. The large-thickness honeycomb deformation process method according to claim 1, characterized by comprising the following steps:

cutting the large-thickness honeycomb according to the required size of the honeycomb sandwich structure, and reserving a certain allowance on each side of the large-thickness honeycomb during cutting;

step two, after protecting the side surface of the large-thickness honeycomb obtained in the step one, placing the large-thickness honeycomb on the molded surface of a mold; the mould is a molded surface mould of a final curved surface of the honeycomb sandwich structure;

step three, pressurizing the large-thickness honeycomb by adopting a vacuumizing mode, heating and keeping for a certain time, wherein the pressurizing pressure is low, and the keeping time is short;

step four, the method of the step three is repeated for a plurality of times, but when the method of the step three is repeated each time, the pressure for pressurization is larger than the pressure of the last time, and the holding time is longer than the time of the last time;

and step five, finishing the deformation of the large-thickness honeycomb after the large-thickness honeycomb is completely attached to the mold and the structure is stabilized.

3. The deformation process method of the large-thickness honeycomb according to claim 2, wherein in the step one, the allowance reserved on each side of the large-thickness honeycomb is 30-70 mm.

4. The method according to claim 2, wherein in the first step, two L-shaped blocks are used to protect two side surfaces of the large-thickness honeycomb in the second step, one L-shaped block has a height equal to the thickness of the large-thickness honeycomb and abuts against two sides of the large-thickness honeycomb, and the other L-shaped block is attached to the mold surface.

5. The deformation process method of the large-thickness honeycomb according to claim 4, wherein in the step one, the length of the side, attached to the mold surface, of the stop block is 1.1-3.0 times of the thickness of the large-thickness honeycomb.

6. A large-thickness honeycomb deformation process method as claimed in claim 2, wherein in the first step, the third step and the fourth step, the mold with sealed honeycomb is sent into an oven or a heating tank, and the heating temperature is 170-220 ℃.

7. The method according to claim 2, wherein in the first step, the first pressurization is performed in a vacuum degree of 0.01MPa to 0.03MPa for a holding time of 1min to 20 min.

8. The method according to claim 7, wherein in the first step, the maximum pressurizing vacuum degree is 0.035MPa to 0.10MPa, and the maximum holding time is 5min to 60 min.

Technical Field

The invention belongs to the technical field of manufacturing of aviation composite materials, and relates to a large-thickness honeycomb process method, in particular to a large-thickness honeycomb deformation process method.

Background

The honeycomb sandwich structure has the characteristics of high strength, light weight, high specific stiffness and the like, and is widely applied to aeronautical composite materials. In the parts such as airplane fairings and the like, because of the requirements on the strength, the rigidity, the weight and the like of materials, a large-thickness honeycomb sandwich structure form is required, and the honeycomb used for forming the sandwich structure is required to be formed by deforming flat plate honeycomb with equal thickness.

In the honeycomb preparation process, the honeycomb is formed by stretching a drop plate, the prepared honeycomb is of a flat plate structure, and in order to enable the honeycomb to adapt to the curved surface of a sandwich structure, appropriate technological measures are adopted to deform the honeycomb; the other method is to completely solidify the honeycomb and deform the honeycomb after solidification, and the method has better honeycomb deformation effect in deformation realization due to smaller honeycomb thickness and smaller honeycomb shape curvature.

For the preparation of large-thickness honeycomb sandwich structures, large-thickness honeycomb deformation is required. The deformation of the large-thickness curved-surface honeycomb generates an arc length difference between the upper surface and the lower surface, one surface of the honeycomb generates a compression effect and the other surface generates a stretching effect, and after the honeycomb deforms to a certain degree due to the limitation of the expansion rate and the elongation rate of the honeycomb, a honeycomb extrusion phenomenon is generated, which destroys the regular hexagon structure of the honeycomb and affects the performance of the honeycomb. However, the method needs to perform a plurality of gluing processes on the honeycomb, and meanwhile, the gluing material in the gluing area of the honeycomb increases the weight of the whole honeycomb sandwich structure, increases a plurality of gluing interfaces, and increases the workload of nondestructive testing of the honeycomb sandwich structure.

Disclosure of Invention

In order to solve the problems, the invention provides a large-thickness honeycomb deformation process method, because a slow pressure application mode is adopted, the honeycomb has sufficient time to adjust the deformation capacity of honeycomb cells in the deformation process, so that the honeycomb cells are uniformly deformed, the honeycomb deformation capacity is indirectly increased, meanwhile, the honeycomb cutting is carried out according to the honeycomb size of a honeycomb sandwich structure, the limitation of a honeycomb allowance area on the honeycomb deformation capacity is cancelled, and the honeycomb deformation capacity is also increased.

The technical scheme of the invention is as follows:

a large-thickness honeycomb deformation process method comprises the steps of cutting a honeycomb according to the size of the honeycomb in a honeycomb sandwich structure in the large-thickness honeycomb deformation process, slowly pressurizing the honeycomb in a vacuumizing mode, keeping for a certain time after pressurization, pressurizing again, repeating the pressurizing process for multiple times until the honeycomb deforms in place, pressurizing the honeycomb by using a pressing plate, and keeping for a certain time to enable the honeycomb to keep a shaped profile.

Further, the method specifically comprises the following steps:

cutting the large-thickness honeycomb according to the required size of the honeycomb sandwich structure, and reserving a certain allowance on each side of the large-thickness honeycomb during cutting;

step two, after protecting the side surface of the large-thickness honeycomb obtained in the step one, placing the large-thickness honeycomb on the molded surface of a mold; the mould is a molded surface mould of a final curved surface of the honeycomb sandwich structure;

step three, pressurizing the large-thickness honeycomb by adopting a vacuumizing mode, heating and keeping for a certain time, wherein the pressurizing pressure is low, and the keeping time is short;

step four, the method of the step three is repeated for a plurality of times, but when the method of the step three is repeated each time, the pressure for pressurization is larger than the pressure of the last time, and the holding time is longer than the time of the last time;

and step five, finishing the deformation of the large-thickness honeycomb after the large-thickness honeycomb is completely attached to the mold and the structure is stabilized.

Further, in the step one, the allowance reserved on each side of the large-thickness honeycomb is 30-70 mm.

Furthermore, in the second step, two L-shaped check blocks are adopted to protect two side faces of the large-thickness honeycomb, the height of one L-shaped check block is equal to the thickness of the large-thickness honeycomb and abuts against two sides of the large-thickness honeycomb, and the other L-shaped check block is attached to the molded surface of the mold.

Furthermore, the length of one side of the stop block attached to the molded surface of the die is 1.1-3.0 times of the thickness of the large-thickness honeycomb.

Further, in the third step and the fourth step, the sealed honeycomb die is sent into an oven or a heating tank, and the heating temperature is 170-220 ℃.

Furthermore, in the third step, the first pressurization is carried out, the vacuum degree is 0.01MPa to 0.03MPa, and the holding time is 1min to 20 min.

Furthermore, in the fourth step, the maximum pressurizing vacuum degree is 0.035 MPa-0.10 MPa, and the maximum holding time is 5 min-60 min.

The invention has the advantages that:

1. the invention can adjust the deformability of the honeycomb cells in a sufficient time in the deformation process of the honeycomb, so that the honeycomb cells are uniformly deformed, and the deformation capability of the honeycomb is indirectly increased;

2. the method of the invention cuts the honeycomb according to the size of the honeycomb sandwich structure, cancels the limit of the honeycomb allowance area on the deformation capability of the honeycomb, and also increases the deformation capability of the honeycomb.

3. The invention solves the problem that the large-thickness honeycomb is seriously extruded in the deformation process, adopts the process of splicing a plurality of honeycombs, increases the gluing process and the nondestructive testing process, improves the manufacturing efficiency and the weight of the large-thickness honeycomb and has larger practical application value.

Drawings

FIG. 1 is a schematic view of a planar, high thickness honeycomb of the present invention;

FIG. 2 is a schematic view of a large thickness honeycomb bonding stop of the present invention;

FIG. 3 is a schematic view of a stopper of the present invention;

FIG. 4 is a schematic view of the initial state of the large thickness honeycomb of the present invention placed on a mold;

FIG. 5 is a schematic representation of the large thickness honeycomb of the present invention after deformation has been completed;

the method comprises the following steps of 1, initial large-thickness honeycomb, 2, a bonding surface, 3, a stopper, 4, a mold, 5, a breathable material, 6, a vacuum bag and 7, and the deformed honeycomb.

Detailed Description

This section is an example of the present invention and is provided to explain and illustrate the technical solutions of the present invention.

A large-thickness honeycomb deformation process method comprises the steps of cutting a honeycomb according to the size of the honeycomb in a honeycomb sandwich structure in the large-thickness honeycomb deformation process, slowly pressurizing the honeycomb in a vacuumizing mode, keeping for a certain time after pressurization, pressurizing again, repeating the pressurizing process for multiple times until the honeycomb deforms in place, pressurizing the honeycomb by using a pressing plate, and keeping for a certain time to enable the honeycomb to keep a shaped profile.

The method specifically comprises the following steps:

cutting the large-thickness honeycomb according to the required size of the honeycomb sandwich structure, and reserving a certain allowance on each side of the large-thickness honeycomb during cutting;

step two, after protecting the side surface of the large-thickness honeycomb obtained in the step one, placing the large-thickness honeycomb on the molded surface of a mold; the mould is a molded surface mould of a final curved surface of the honeycomb sandwich structure;

step three, pressurizing the large-thickness honeycomb by adopting a vacuumizing mode, heating and keeping for a certain time, wherein the pressurizing pressure is low, and the keeping time is short;

step four, the method of the step three is repeated for a plurality of times, but when the method of the step three is repeated each time, the pressure for pressurization is larger than the pressure of the last time, and the holding time is longer than the time of the last time;

and step five, finishing the deformation of the large-thickness honeycomb after the large-thickness honeycomb is completely attached to the mold and the structure is stabilized.

In the first step, the allowance reserved on each side of the large-thickness honeycomb is 30-70 mm.

And in the second step, two L-shaped check blocks are adopted to protect two side surfaces of the large-thickness honeycomb, the height of one L-shaped check block is equal to the thickness of the large-thickness honeycomb and abuts against two sides of the large-thickness honeycomb, and the other L-shaped check block is attached to the molded surface of the mold.

The length of one side of the stop block, which is attached to the molded surface of the die, is 1.1-3.0 times of the thickness of the large-thickness honeycomb.

And step three and step four, conveying the sealed honeycomb mould into an oven or a heating tank, wherein the heating temperature is 170-220 ℃.

In the third step, the first pressurizing is carried out, the vacuum degree is 0.01MPa to 0.03MPa, and the holding time is 1min to 20 min.

In the fourth step, the maximum pressurizing vacuum degree is 0.035 MPa-0.10 MPa, and the maximum holding time is 5 min-60 min.

The principle of the invention is as follows:

the method provided by the invention aims at the deformation process of the large-thickness honeycomb, in the deformation process of the large-thickness honeycomb, firstly, the honeycomb is cut according to the size of the honeycomb in a honeycomb sandwich structure, the limitation of the deformation allowance of the honeycomb is reduced, then, the honeycomb is slowly pressurized in a vacuumizing mode, the honeycomb is kept for a certain time after pressurization, the honeycomb is subjected to an adjusting process for a certain time, then, the pressurizing process is carried out again, the process is repeated for many times, and after the honeycomb is deformed in place, the honeycomb is pressurized by a pressure plate, and the heat is preserved for a certain time, so that the honeycomb keeps a shaped profile.

The implementation steps of the measures are as follows: firstly, cutting a honeycomb according to the required size of a honeycomb sandwich structure, wherein each side of the honeycomb is reserved with a margin of 30-70 mm to obtain the honeycomb; and bonding the honeycomb side face protection stop block to the side face of the honeycomb by using a room temperature curing adhesive film or an adhesive, wherein the honeycomb side face stop block is made of metal or a composite material, the stop block is L-shaped, the H-direction length of the stop block is the same as the thickness of the shaped honeycomb, and the L-direction length is 1.1-3.0 times of the H-direction length. Placing the honeycomb on the surface of a mold, laying a breathable material on the surface of the honeycomb, sealing by using a vacuum bag, conveying the mold with the sealed honeycomb into an oven, heating to 170-220 ℃, pressurizing the honeycomb by adopting a vacuumizing mode, starting to have a vacuum degree of 0.01-0.03 MPa, keeping the vacuum degree for 1-20 min, then increasing the vacuum degree to 0.035-0.10 MPa, and keeping the vacuum degree for 5-60 min. And after the heat preservation is finished, finishing honeycomb shaping to obtain the deformed honeycomb.

The method comprises the following specific steps:

step one, cutting the honeycomb according to the required size of the honeycomb sandwich structure, wherein each side of the honeycomb is reserved with a margin of 30-70 mm.

And step two, bonding a protective baffle at the edge of the honeycomb, placing the honeycomb on the surface of a honeycomb shaping mold, laying a breathable material on the surface of the honeycomb, and sealing a vacuum bag.

The honeycomb edge protection baffle is of a combined structure and is L-shaped, the H-direction length of the baffle is the same as the thickness of the shaped honeycomb, and the L-direction length is 1.1-3.0 times of the H-direction length

When the honeycomb side block is bonded with the honeycomb, room temperature curing adhesive or pressure sensitive adhesive tape is used for bonding.

And step three, conveying the sealed honeycomb mould into an oven, heating to 170-220 ℃, preferably 180-195 ℃, pressurizing the honeycomb by adopting a vacuumizing mode, starting to have the vacuum degree of 0.01-0.03 MPa, keeping the vacuum degree for 1-20 min, preferably 5-10 min, then increasing the vacuum degree to 0.035-0.10 MPa, preferably 0.035-0.05 MPa, and keeping the vacuum degree for 5-60 min, preferably 20-40 min.

When the honeycomb is shaped, the highest temperature is increased to 10-30 ℃ above the Tg of the honeycomb impregnating adhesive.

Or as an example:

according to the design of a large-thickness honeycomb sandwich structure, the large-thickness honeycomb is deformed, and the specific manufacturing process is as follows:

cutting according to the thickness of 60mm to the size of 1200mm multiplied by 1800mm, and reserving 50mm allowance on each side, namely the size of the honeycomb after cutting is 1300mm multiplied by 1900 mm;

and step two, the honeycomb edge protection baffle is of a combined structure, the honeycomb side baffle is made of aluminum and is formed by combining small sections with the length of 250mm, the H-direction length of the side baffle is 60mm, the H-direction length of the side baffle is 100mm, and the honeycomb side protection baffle is bonded with the honeycomb by adopting FN-305 adhesive.

And adhering a protective baffle plate on the edge of the honeycomb, placing the honeycomb on the surface of a honeycomb shaping mold, laying a breathable material on the surface of the honeycomb, and sealing a vacuum bag.

And step three, conveying the sealed honeycomb mould into an oven, heating to 180-190 ℃, pressurizing the honeycomb by adopting a vacuumizing mode, starting to have the vacuum degree of 0.02-0.025 MPa, keeping the vacuum degree for 10min, and then increasing the vacuum degree to 0.030-0.035 MPa, wherein the vacuum keeping time is 40 min.

And step four, cooling the honeycomb shaping mold under the condition of vacuumizing and pressurizing.