CN-122008587-A - Manufacturing method of carbon fiber connector of engine shell

CN122008587ACN 122008587 ACN122008587 ACN 122008587ACN-122008587-A

Abstract

The invention discloses a manufacturing method of an engine shell carbon fiber joint in the technical field of space engines, which comprises the steps of dividing the joint into a flat layer, a side cladding layer and a lower cladding layer, wherein the flat layer is a bearing core area, carrying out vacuum compaction and cold pressing pre-curing in stages in the paving process of the flat layer to enable resin to stabilize an interlayer structure in a partially crosslinked state, embedding the flat layer into an annular area surrounded by the side cladding layer and the lower cladding layer, constructing a gradient stress transmission structure through flanging lap joint and continuous adhesive film transition, and finally carrying out surface activation treatment in an embedded part bonding area. The invention controls the combination quality of the internal curing stress and the interlayer by the sectional pre-curing and gradient interface design, effectively inhibits the debonding and cracking of the composite material caused by uneven shrinkage or weak interface under the high-pressure and thermal cycle environment, and remarkably improves the structural integrity and long-term reliability of the joint.

Inventors

LI JUN
WEI JIACHAO
YANG HENG
TANG WEI
XIE YAFANG

Assignees

江苏新扬新材料股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260410

Claims (10)

1. A method for manufacturing a carbon fiber joint of an engine housing, comprising the steps of: s1, carrying out regional division on a shell joint, wherein one partition is divided into tiled layers and is used for bearing main loads; s2, paving a layer, namely paving the prepreg of the layer by adopting a sectional progressive paving forming process; S3, joint forming and paving, namely paving a side cladding and a lower cladding in different areas, coating an adhesive film, overlapping a flat paving layer by flanging, and performing reinforcement paving; s4, solidifying, namely demoulding after solidifying the joint semi-finished product to form a joint body; s5, installing the embedded part, namely, pre-forming an adhesion area in the joint body, and synchronously carrying out non-adhesion surface protection and adhesion surface activation treatment on the metal embedded part, and then, carrying out cooperative installation on the embedded part.
2. The method for manufacturing a carbon fiber joint for an engine housing according to claim 1, wherein in the step S1, the flow of the region division is specifically as follows: S11, coating a layer of temporary resin film on the surface of a die cavity, and carrying out heat preservation treatment under the condition of low pressure and constant temperature; s12, recording an imprint trace formed by natural flow of the temporary resin; S13, dividing a die cavity into a flat layer, a side cladding layer and a lower cladding layer according to the geometric form and the distribution density of the imprint marks; wherein, the continuous, dense and banded gathered trace areas correspond to the flat layer, and the intermittent, divergent or vortex trace areas correspond to the side cladding and the lower cladding.
3. The method for manufacturing a carbon fiber joint for an engine casing according to claim 2, wherein the region is divided into a flat layer, a side cladding layer and a lower cladding layer; the divided areas are marked as an area one, an area two, an area three, an area four and an area five; Defining a second area as a paving layer; Defining a first region and a fifth region as side cladding layers; Defining a third region and a fourth region as a lower cladding; the side cladding and the lower cladding are contour structure areas, and the tiled layer is formed in a sealing mode; wherein each area of the layer comprises prepreg layer units, and the layer units are sequentially laid at angles of 45 degrees, -0 degrees, -45 degrees and 90 degrees; The ply units are stacked in a periodic manner in the thickness direction; In the laying process, the first layer of prepreg is subjected to vacuum-pumping compaction after being laid, and vacuum-pumping compaction is carried out once every 4 layers.
4. The method for manufacturing a carbon fiber joint for an engine housing according to claim 1, wherein in the step S2, the step S2 is specifically: s21, preparing prepreg sheets in each region based on the part structure; s22, circularly paving based on the paving angles of the prepreg of the paving layers, and uniformly dividing the whole body into three layers of sections for paving; The first section layer is paved and stuck, and then vacuumized and compacted to form a first prefabricated body and package a vacuum bag; then, after paving the secondary section layer, vacuumizing and compacting to form a first prefabricated body and packaging a vacuum bag; Finally, carrying out vacuum pumping compaction after carrying out final-section layer paving to form a flat paving layer prefabricated body, and installing an upper ring die; Wherein the first preform and the second preform are respectively subjected to cold pressing pre-curing; s23, transferring the flat layer prefabricated body provided with the upper ring mold to a hot press for curing treatment; s24, demolding the flat layer, and marking the part according to the mold mark; s25, checking the appearance structure of the paving layer and each dimension parameter.
5. The method for manufacturing a carbon fiber joint for an engine housing according to claim 1, wherein in the step S2, the cold press pre-curing is specifically: 1) Vacuum pressure is applied to be less than or equal to minus 0.095MPa; 2) Heating to 120+/-5 ℃, wherein the heating rate is 1.0-2.0 ℃ per minute, and the temperature of the medium is set to 125 ℃; after the fastest temperature rising thermocouple is heated to 40 ℃, starting to pressurize to 0.6+/-0.02 MPa, and keeping constant pressure; after the slowest temperature-rising thermocouple is heated to 115 ℃, keeping the temperature constant for 110-120 min; And then cooling to below 60 ℃ at a speed of 2.0 ℃ per minute or less, releasing pressure, and opening the tank when the temperature of the thermocouple which is cooled most rapidly is reduced to below 50 ℃.
6. The method for manufacturing a carbon fiber joint for an engine housing according to claim 3, wherein the step S3 is specifically: The strategy of paving the lower cladding layer and then paving the side cladding layer is adopted, wherein the joint sealing surface of the lower cladding layer and the side cladding layer is in cross lap joint, and the lap joint interfaces of the upper layer and the lower layer are arranged in a staggered manner along the axial direction; Firstly paving a third region in the lower cladding layer, and then paving a fifth region in the side cladding layer; After the first layer of lower cladding prepreg is paved, applying vacuum pressure to the corners of the paving area for local compaction; then, paving the fourth region and the first region, and adopting a strategy of paving the lower cladding layer and then paving the side cladding layer preferentially; after the paving is finished, covering the same resin system adhesive film on the surface of the paving layer of the first, third, fourth and fifth areas to form a sealing layer for interface enhancement.
7. The method for manufacturing the carbon fiber connector of the engine shell according to claim 6, wherein the second area is a flat layer, and surface mechanical polishing, absolute ethyl alcohol cleaning and constant-temperature drying at 70 ℃ are sequentially carried out for 2 hours before the flat layer is filled; After a layer of adhesive film with a resin system is applied to the surface of the dried tiled layer, the adhesive film is aligned and embedded into the layering gaps of the first, third, fourth and fifth areas by using an internal annular reference; filling gaps between the second region and the paving layers of all the peripheral regions point by adopting carbon fiber wires after embedding, and compacting; after filling, carrying out layering flanging treatment on the edges of the lower cladding and the side cladding; The flanging operation is carried out layer by layer, one layer is turned over every time, a layer of prepreg is sequentially paved on the surface of the flanging layer, and 8 layers of flanging lap joints are accumulated; the flanging lap joint area and the adhesive film layer of the area II form a continuous resin transition structure; after the paving and flanging are completed, the upper die is arranged on the paving surface to complete packaging.
8. The method for manufacturing a carbon fiber joint for an engine housing according to claim 1, wherein in the step S23 and the step S4, the curing process is specifically: Transferring the product into a hot press, heating to 70 ℃, and preserving heat for 2 hours; then, heating to 130 ℃, and preserving heat for 1h; then, heating to 160 ℃, and preserving heat for 3 hours; Finally, the temperature is raised to 180 ℃ and kept for 1.5 hours.
9. The method for manufacturing the carbon fiber connector of the engine shell according to claim 1, wherein a contour-shaped concave cavity for accommodating an embedded part is reserved in an adhesion area of the carbon fiber connector body, and a non-adhesion part of the embedded part is covered with a demolding material for isolation; Wherein, the adhesive surface is coated with adhesive after surface roughening treatment; placing the embedded part into the concave cavity, applying local pressure, removing the demolding material after curing, and cleaning the glue overflow; the curing is specifically that the joint body is placed in an oven for curing for 24 hours at 50 ℃; After the solidification is finished, detecting whether the debonding and adhesive layer hollowing exist or not, and then carrying out the subsequent machining process.
10. The method for manufacturing the carbon fiber connector of the engine shell according to claim 9, wherein after the embedded part is placed in the engine shell, the embedded part is symmetrically pressed by two ends by a clamp, and whether the axial positioning of the embedded part is uniformly attached to the adhesive layer or not is detected; The direction of the pressing force corresponds to the boss and the cylindrical structure of the embedded part.

Description

Manufacturing method of carbon fiber connector of engine shell Technical Field The invention relates to the technical field of aerospace engines, in particular to a manufacturing method of an engine shell carbon fiber connector. Background The existing aeroengine shell is generally formed by integrally forging high-temperature alloy or by machining after split welding. The metal material structure has excellent high-temperature strength, creep property and long-term service reliability, and can meet severe high-temperature, high-pressure and complex load environments of an engine. However, the high density of the metal material results in high overall weight of the housing, which severely restricts the improvement of the thrust-weight ratio and the fuel efficiency of the engine. In order to reduce the weight, attempts have been made to use low-density metals such as titanium alloys, but there are still limitations in terms of high-temperature performance. Therefore, the continuous carbon fiber reinforced resin matrix composite material with high specific strength, specific rigidity and designability is used for replacing a metal material to manufacture the engine shell joint, so that the engine shell joint becomes a main technical direction for realizing the light weight of the structure, and the core aim is to remarkably reduce the quality of the part while maintaining and even improving the structural performance. In order to achieve the above-mentioned light weight goal, it is generally sought in the industry to manufacture a composite engine housing joint using an integrated molding process to reduce the additional weight and risk of stress concentrations associated with mechanical connections. However, such integrated molding processes face delamination defects when manufacturing joints that are complex curved surfaces, have a variable thickness, and are subject to high stresses and severe thermal environments. The method is characterized in that in the solidifying and cooling process, due to the factors of the difference of solidification shrinkage rate of resin matrixes in different layering areas, insufficient bonding strength of interlayer interfaces, uneven solidification pressure distribution, insufficient infiltration, volatile residue and the like, partial or whole separation and cracking phenomena are generated between the composite material layers, and the layering defects seriously weaken the whole bearing capacity of the joint, damage the integrity of the structure and are extremely easy to cause early failure under the high pressure, vibration and thermal shock load in the engine, so that the method for manufacturing the carbon fiber joint of the engine shell is provided. Disclosure of Invention Aiming at the defects existing in the prior art, the invention provides a manufacturing method of the carbon fiber connector of the engine shell, which effectively inhibits solidification layering and interface debonding through sectional pre-solidification and gradient interface design, and remarkably improves the structural integrity and bearing durability of the carbon fiber connector in a high-pressure heat load environment. The invention discloses a manufacturing method of a carbon fiber joint of an engine shell, which comprises the following steps: s1, carrying out regional division on a shell joint, wherein one partition is divided into tiled layers and is used for bearing main loads; s2, paving a layer, namely paving the prepreg of the layer by adopting a sectional progressive paving forming process; S3, joint forming and paving, namely paving a side cladding and a lower cladding in different areas, coating an adhesive film, overlapping a flat paving layer by flanging, and performing reinforcement paving; s4, solidifying, namely demoulding after solidifying the joint semi-finished product to form a joint body; s5, installing the embedded part, namely, pre-forming an adhesion area in the joint body, and synchronously carrying out non-adhesion surface protection and adhesion surface activation treatment on the metal embedded part, and then, carrying out cooperative installation on the embedded part. Optionally, in step S1, the flow of the region division specifically includes: S11, coating a layer of temporary resin film on the surface of a die cavity, and carrying out heat preservation treatment under the condition of low pressure and constant temperature; s12, recording an imprint trace formed by natural flow of the temporary resin; S13, dividing a die cavity into a flat layer, a side cladding layer and a lower cladding layer according to the geometric form and the distribution density of the imprint marks; wherein, the continuous, dense and banded gathered trace areas correspond to the flat layer, and the intermittent, divergent or vortex trace areas correspond to the side cladding and the lower cladding. Optionally, the region is divided into a flat layer, a side cladding layer and a lowe