CN-122008597-A - Manufacturing method of composite sandwich structure oil tank

CN122008597ACN 122008597 ACN122008597 ACN 122008597ACN-122008597-A

Abstract

The invention discloses a manufacturing method of a composite sandwich structure oil tank, which comprises the following steps of S1, preparing a mould, S2, paving and solidifying an inner skin, paving an inner skin prepreg on the mould, introducing a layer of polyvinyl fluoride waterproof film between the prepregs in the paving process, and then carrying out primary solidifying and forming, S3, integrating a core material, sequentially placing and fixing a foam core and a honeycomb core on the solidified inner skin, S4, paving and solidifying an outer skin prepreg on the surface of the integrated core material, and carrying out core material solidifying and forming, S5, demoulding and post-treatment. The invention ensures that the waterproof film is firmly attached to the base material and has no fold defect, greatly strengthens the sealing protection effect of the inner molded surface of the oil tank by virtue of the excellent permeation resistance, abrasion resistance and extensibility of the polyvinyl fluoride waterproof film, effectively blocks the fuel permeation path and effectively solves the problem of fuel leakage of an aircraft caused by stress concentration or product defect in the prior art.

Inventors

LI JUN
XIE YAFANG
TANG WEI
WEI JIACHAO

Assignees

江苏新扬新材料股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260318

Claims (10)

1. The manufacturing method of the composite sandwich structure oil tank is characterized by comprising the following steps of: s1, preparing a die; S2, paving and curing an inner skin, namely paving an inner skin prepreg on a die, introducing a layer of polyvinyl fluoride waterproof film between the prepregs in the paving process, and then performing primary curing molding; s3, integrating the core material, namely sequentially placing and fixing a foam core and a honeycomb core on the cured inner skin; S4, paving and curing the outer skin, namely paving an outer skin prepreg on the surface of the integrated core material, and curing and forming the core material; and S5, demolding and post-treatment.
2. The method of manufacturing a composite sandwich structure fuel tank of claim 1 wherein in step S2, the laminate structure after the introduction of the polyvinyl fluoride waterproof film is subjected to vacuum compaction treatment, and after compaction, wrinkles of the film surface are inspected and treated.
3. The method of manufacturing a composite sandwich fuel tank of claim 1 further comprising applying a hat stiffener between said foam core and said honeycomb core in step S3.
4. A method for manufacturing a composite sandwich structure fuel tank as set forth in claim 3, wherein in step S3, both the foam core and the honeycomb core are subjected to dehumidification pretreatment before being placed, an adhesive film is wrapped on the outer surface of the foam core, and the adhesive film is laid between the honeycomb core and the inner skin.
5. The method for manufacturing a composite sandwich oil tank as claimed in claim 4, wherein the foam core and the honeycomb core are positioned and laid by combining laser projection with positioning release cloth.
6. The method for manufacturing the composite sandwich structure fuel tank of claim 1, wherein the step S2 and the step S4 are respectively carried out by adopting a layered vacuumizing compaction process, wherein the starting point of single vacuumizing compaction is that the vacuum degree in a vacuum bag is less than or equal to-0.095 MPa.
7. The method for manufacturing a composite sandwich oil tank according to claim 1, wherein the first curing molding and the core curing molding are performed in an autoclave, the pressure of the first curing molding is 0.5-0.7MPa, and the pressure of the core curing molding is 0.1-0.3MPa.
8. The method of claim 7, wherein the core material is cured and formed by vacuum-pumping the curing system without applying external positive pressure.
9. The method of manufacturing a composite sandwich fuel tank of claim 3 further comprising a core inspection and repair step after step S3 and before step S4 for inspecting and filling broken cells of the honeycomb core and for filling gaps between the cap-type reinforcing ribs and the honeycomb core when present.
10. The method of manufacturing a composite sandwich fuel tank of claim 1, wherein the post-processing includes non-destructive inspection, cutting and edge sealing of the demolded component.

Description

Manufacturing method of composite sandwich structure oil tank Technical Field The invention relates to the technical field of aircrafts, in particular to a manufacturing method of a composite sandwich structure oil tank. Background In the aerospace field, the endurance, the flight safety and the operation economy of an aircraft are core indexes for measuring the performance of the aircraft, and the design and the manufacture of a fuel storage system directly affect the key performance. The aircraft fuel tank is used as a core component for fuel storage, not only needs to have enough structural strength to bear various loads in the flight process, but also needs to meet strict tightness requirements, and safety accidents caused by fuel leakage are avoided. With the continuous development of aviation technology, modern high-performance aircrafts generally adopt an integral type oil tank design, and the oil tank is arranged by utilizing the internal structural space of the aircraft body, so that the fuel oil storage capacity can be maximized, the endurance mileage can be prolonged, the additional structural weight can be reduced, and the flying energy consumption can be reduced, and therefore, the integral type oil tank becomes the main stream configuration of an advanced aircraft. At present, the manufacturing materials of the aircraft fuel tank are gradually transformed into composite materials, and the composite material sandwich structure is widely applied to manufacturing of the fuel tank main body structure due to the advantages of high specific strength, corrosion resistance, light weight and the like. The existing manufacturing process of the composite sandwich structure fuel tank mostly adopts a layered composite molding mode of skin-core material-skin, and the whole processing is completed through the working procedures of paving prepreg, assembling core material, curing molding and the like. In a specific manufacturing process, in order to ensure structural integrity, an adhesive layer is generally disposed between the core material and the skin, and a reinforcing structure is additionally disposed between the core materials, so as to improve the load-resisting capacity of the fuel tank. Meanwhile, in order to meet the sealing requirement, part of the process adopts gluing, film pasting and other modes to seal the surface or the interlayer of the skin. However, the existing manufacturing process of the composite sandwich structure fuel tank still has a certain problem, so that the fuel tank faces the situation of fuel leakage in actual use, on one hand, the forming process of the composite sandwich structure involves the defects of uneven paving, uneven cementing or improper control of solidification parameters, such as tiny pores and interface separation, of the bonding surfaces among the layers of materials, which can be gradually expanded under the complex working conditions of vibration, pressure change and the like of aircraft flight to form a fuel leakage channel, on the other hand, when the fuel tank bears flying load for a long time, stress is easy to concentrate at the joint of a core material and a reinforcing structure, the positions of a skin corner and the like, so that cracks appear in the region, and the sealing performance of the fuel tank is further damaged, and in addition, the positioning precision of the core material is insufficient, the dehumidification treatment is not thorough, the bonding strength of the core material and the skin is reduced, and the probability of sealing failure is further increased. These problems not only affect the endurance stability of the aircraft, but also are more likely to cause serious flight accidents such as fire disaster, structural failure and the like due to fuel leakage, and form a serious threat to flight safety, so that a manufacturing method of the fuel tank with the composite sandwich structure is urgently needed to solve the problems. Disclosure of Invention The invention aims to provide a novel technical scheme of a manufacturing method of a composite sandwich structure oil tank, which is characterized in that a polyvinyl fluoride waterproof film is introduced between inner skin prepreg layers, and a layered vacuumizing compaction, precise positioning and differential curing process is matched, so that the high tightness of the oil tank is realized, and the problem of fuel leakage caused by stress concentration or product defects is solved. According to a first aspect of the present invention, there is provided a method of manufacturing a composite sandwich structure fuel tank, comprising the steps of: s1, preparing a die; S2, paving and curing an inner skin, namely paving an inner skin prepreg on a die, introducing a layer of polyvinyl fluoride waterproof film between the prepregs in the paving process, and then performing primary curing molding; s3, integrating the core material, namely sequentially placing and fixing a foam core an