CN103407175B - A kind of integral forming method of fiber-reinforced resin matrix compound material wing box - Google Patents

Abstract

An overall molding method for a fiber-reinforced resin-based composite material wing box, which has eight major steps: 1. Determine the structural design scheme of the fiber-reinforced resin-based composite material wing box; 2. According to the structural design of the fiber-reinforced resin-based composite material wing box The plan determines the mold plan; 3. Prepare the water-soluble core; 4. Prepare the fiber preform of the fiber-reinforced resin-based composite wing box; 5. Put the fiber preform of the fiber-reinforced resin-based composite wing box into the mold and Positioning and mold closing; 6. Vacuuming, injecting resin and heating and curing; 7. Opening the mold to take out the fiber-reinforced resin-based composite wing box with a water-soluble core; 8. Composite the water-soluble core from the fiber-reinforced resin base with water After the material is dissolved in the inner cavity of the wing box, the fiber-reinforced resin matrix composite material wing box is finally obtained. The invention is suitable for the integral molding of the fiber-reinforced resin-based composite material wing box with complex inner cavity structure, and has low cost.

Description

A method for integral molding of fiber-reinforced resin-based composite material wing box

technical field

The invention provides an integral molding method for a wing box of a fiber-reinforced resin-based composite material, which belongs to the technical field of composite material manufacturing.

Background technique

The wing box is the main load-bearing structure of the aircraft, which bears various loads transmitted from the wings and the fuselage during the take-off, cruise and landing of the aircraft. The traditional aircraft wing box is assembled by many metal parts, so the structure weight is relatively large, which is not conducive to the weight reduction of the aircraft. In contrast, composite materials have high specific strength, high specific stiffness, and designability, so they have been widely used in aeronautical structures in recent years. For example, the composite center wing box of the Airbus A380 is comparable The specific weight loss is nearly 1.5 tons. The integral molding technology of composite materials can further reduce the structural assembly weight, which is one of the inevitable trends in the weight reduction design of large components such as wing boxes in the future. The resin transfer molding process (RTM) has low cost and high molding quality, and can meet the overall molding needs of large components such as composite wing boxes in industry. However, the interior of the composite wing box usually contains many reinforcement structures, and the shape of the inner cavity is complex. The traditional RTM method generally uses a metal core, which is difficult to demould, and some structural designs of the composite wing box cannot be demolded during the manufacturing process. It cannot be realized, which affects the application of some advanced design schemes, so it needs to be improved.

Contents of the invention

The purpose of the present invention is to provide an integral molding method of fiber-reinforced resin-based composite material wing box to solve the technical problem of difficult demoulding when preparing fiber-reinforced resin-based composite material wing box with complex inner cavity structure by traditional RTM method.

The technical scheme adopted in the present invention is as follows:

The present invention is an integral molding method of a fiber-reinforced resin-based composite material wing box, the steps of which are as follows:

Step 1: Determine the structural design scheme of the fiber-reinforced resin-based composite material wing box.

Step 2: Determine the mold scheme according to the structural design scheme of the fiber-reinforced resin-based composite material wing box, including the mold for preparing the water-soluble core and the mold for preparing the fiber-reinforced resin-based composite material wing box.

Step 3, preparing a water-soluble core.

Step 4: Lay the fiber cloth according to the designed laying scheme, and use a sizing agent to shape the layers of the fiber cloth to prepare a fiber preform of the fiber-reinforced resin-based composite material wing box.

Step 5: Put the prepared fiber preform of the fiber-reinforced resin-based composite material wing box into the mold, and then position and close the mold.

Step 6: Vacuumize. When the vacuum degree reaches the requirement of -0.1, start to inject resin into the mold to fill the gap between the fiber preforms of the fiber-reinforced resin-based composite material wing box, and wait for the resin to fill the fiber-reinforced resin-based composite material wing box. After the gap of the fiber preform, the temperature is raised and cured according to the curing process regulations of the resin.

Step 7. After curing, cool the mold to room temperature, open the mold, and take out the cured fiber-reinforced resin-based composite material wing box. At this time, the inner cavity of the fiber-reinforced resin-based composite material wing box still has water-soluble core.

Step 8: After dissolving the water-soluble core with water from the inner cavity of the fiber-reinforced resin-based composite material wing box, the fiber-reinforced resin-based composite material wing box is finally obtained.

Among them, the "structural design plan" described in step 1 needs to be designed according to the technical indicators. The structure of the fiber-reinforced resin-based composite material wing box is composed of one or more cavities, and each cavity can be designed as required Constant section or variable section, the cross-sectional shape of each cavity can be trapezoidal, parallelogram, triangle, variable arc closed contour shape, in a word, the shape of each cavity can be arbitrary, fiber reinforced resin matrix composite material Part of the wing box has or does not have stiffeners and stiffeners.

Among them, the "water-soluble core" described in step 2 is made of a water-soluble material, which is in powder form, is poured into the inner cavity of the mold after being added and mixed, and can be A water-soluble core with the same shape as the mold is obtained. The water-soluble core has stable physical and chemical properties at room temperature and high temperature. When preparing a fiber-reinforced resin-based composite wing box, the high-temperature environment of the resin curing process The water-soluble core can maintain the designed appearance, and the core will not be decomposed or damaged. After the resin is cured and cooled to room temperature, the water-soluble core can be dissolved by water.

Wherein, the "designed lay-up plan" described in step 4 is usually a balanced and symmetrical lay-up plan, and the specific number of lay-up layers, lay-up angles and lay-up ratios shall be designed according to the indicators to be realized; in step The "setting agent" mentioned in the fourth is a kind of polymer material, which needs to have good compatibility with the resin used to prepare the wing box of fiber-reinforced resin matrix composite material. Play a shaping role, so that the fiber preform of the fiber-reinforced resin-based composite material wing box has a certain integrity. The fiber of " fiber cloth " described in step 4 can be a kind of in carbon fiber, glass fiber, Kevlar fiber, boron fiber and plant fiber;

Among them, the "curing process specification" mentioned in step 6 refers to the regulation of relevant process parameters during the entire curing process of the resin, and each type of resin corresponds to a corresponding curing process specification. The "resin" mentioned in step six may be one of epoxy resin, polyimide, thermoplastic polyurethane, polyamide, polyphenylene sulfide, polyaryletherketone and polyvinyl alcohol. For the RTM overall molding process, the pressure of injecting resin into the mold is controlled above 0.5MPa.

The invention relates to an integral molding method of a fiber-reinforced resin-based composite material wing box, which has the beneficial effect of being suitable for the integral molding of a fiber-reinforced resin-based composite material wing box with a complex inner cavity structure, and has low cost.

Description of drawings

Fig. 1 is a flowchart of the method of the present invention.

Figure 2 is a schematic diagram of the geometric configuration of the composite wing box.

Figure 3 is the mold and core used to prepare the composite material wing box.

Fig. 4 is the mold for preparing the water-soluble core.

In Figure 2: 1. Left C-shaped beam, 2. Upper skin, 3. Right C-shaped beam, 4. Lower skin, 5. Internal rectangular box beam, 6. Triangular area

Among Fig. 3: 7. patrix, 8. left C-shaped mandrel, 9. lower mold, 10. right C-shaped mandrel, 11. sealing strip, 12. central water-soluble core, 13. left end cap, 14. Right end cap.

Among Fig. 4: 15. rear end cover, 16. central rigid frame, 17. front end cover, 18. upper side plate, 19. left side plate, 20. lower side plate, 21. right side plate.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and implementation examples.

The flow chart of the present invention is shown in Figure 1. First, determine the structural design scheme of the fiber-reinforced resin-based composite material wing box, then determine the mold scheme according to the structural design scheme of the fiber-reinforced resin-based composite material wing box, and use the prepared mold to prepare The water-soluble core, on this basis, prepares the fiber preform of the fiber-reinforced resin-based composite material wing box, puts the prepared fiber-reinforced resin-based composite material wing box fiber preform into the mold and positions the mold, Then vacuumize, inject resin and heat up to cure. After the curing is completed, open the mold and take out the fiber-reinforced resin-based composite wing box with the water-soluble core, and finally remove the water-soluble core from the fiber-reinforced resin-based composite wing box with water. After dissolving out of the inner cavity of the fiber reinforced resin matrix composite material, the wing box is finally obtained. Concrete implementation steps of the present invention are as follows:

Step 1: Determine the structural design scheme of the fiber-reinforced resin-based composite material wing box.

Among them, the "structural design plan" described in step 1 needs to be designed according to the technical indicators. The structure of the fiber-reinforced resin-based composite material wing box is composed of one or more cavities, and each cavity can be designed as required Constant section or variable section, the cross-sectional shape of each cavity can be trapezoidal, parallelogram, triangle, variable arc closed contour shape, in a word, the shape of each cavity can be arbitrary, fiber reinforced resin matrix composite material Part of the wing box has or does not have reinforcing ribs and ribs. In this embodiment, the selected fiber reinforced resin matrix composite wing box design scheme is shown in Figure 2. It is a single-cavity equal-section structure, and the cavity shape is It is rectangular, and the fiber-reinforced resin-based composite material wing box is composed of a left C-shaped beam 1, an upper skin 2, a right C-shaped beam 3, a lower skin 4, an inner rectangular box beam 5 and a triangular area 6.

Step 2. Determine the mold scheme according to the design scheme of the fiber-reinforced resin-based composite material wing box, including the mold for preparing the fiber-reinforced resin-based composite material wing box and the mold for preparing the water-soluble core.

Among them, the "water-soluble core" described in step 2 is made of a water-soluble material, which is in powder form, is poured into the inner cavity of the mold after being added and mixed, and can be A water-soluble core with the same shape as the mold is obtained. The water-soluble core has stable physical and chemical properties at room temperature and high temperature. When preparing a fiber-reinforced resin-based composite wing box, the high-temperature environment of the resin curing process The water-soluble core can maintain the designed appearance, and the core will not decompose or be damaged. After the resin is cured and cooled to room temperature, the water-soluble core can be dissolved by water; Composite wing box mold" is shown in Figure 3, consisting of an upper mold 7, a left C-shaped core 8, a lower mold 9, a right C-shaped core 10, a sealing strip 11, a central water-soluble core 12, and a left end cover 13 and the right end cover 14, the upper mold 7 is attached to the upper skin, the left C-shaped core 8 is attached to the left C-shaped beam 1, the lower mold 9 is attached to the lower skin 4, and the right C-shaped core 10 is attached to the right The C-shaped beam 3 is bonded, the central water-soluble core 12 is bonded to the inner surface of the inner rectangular box beam 5, the upper mold 7 and the lower mold 9 can make the left C-shaped core 8, the right C-shaped core 10, and the left end cover 13 Positioning with the right end cover 14, the left end cover 13 and the right end cover 14 can position the central water-soluble core 12, and the sealing strip 11 is made of silica gel material, which has relatively good sealing and elasticity, and seals the entire set of molds; The "mold for preparing a water-soluble core" described in step 2 is shown in Figure 4, consisting of a rear end cover 15, a central rigid framework 16, a front end cover 17, an upper side plate 18, a left side plate 19, and a lower side plate 20 And right side plate 21, wherein upper side plate 18, left side plate 19, lower side plate 20 and right side plate 21 are assembled to form rectangular cavity and can be used to prepare central water-soluble core 12, and central rigid skeleton 16 pairs central water-soluble The core 12 acts as a reinforcement to prevent the central water-soluble core 12 from being crushed during the mold closing process, and the central rigid skeleton 16 is positioned through the rear end cover 15 and the front end cover 17 .

Step 3, preparing a water-soluble core.

Among them, after the "water-soluble core" described in step 4 is processed according to the molding process of the water-soluble core, a layer of nano-material protective film is coated on its surface for sealing treatment, and a layer of PTFE film, to ensure the surface finish of the core, while preventing the resin from penetrating into the water-soluble core.

Step 4: Lay the fiber cloth according to the designed laying scheme, and use a sizing agent to shape the layers of the fiber cloth to prepare a fiber preform of the fiber-reinforced resin-based composite material wing box.

Wherein, the "designed lay-up plan" described in step 4 is usually a balanced and symmetrical lay-up plan, and the specific number of lay-up layers, lay-up angles and lay-up ratios shall be designed according to the indicators to be realized; in step The fiber of the "fiber cloth" described in four can be carbon fiber, glass fiber, Kevlar fiber, boron fiber or plant fiber; The resin of the fiber-reinforced resin-based composite wing box has good compatibility, and a small amount of sizing agent can be added between the fiber cloth layers to play a role in shaping, so that the fiber preform of the fiber-reinforced resin-based composite wing box has a certain integrity; since the fiber-reinforced resin matrix composite wing box is composed of left C-shaped beam 1, upper skin 2, right C-shaped beam 3, lower skin 4, inner rectangular box beam 5 and triangular area 6, the fiber When reinforcing the fiber preform of the resin-based composite wing box, it is necessary to prepare the fibers of the left C-beam 1, the upper skin 2, the right C-beam 3, the lower skin 4, the inner rectangular box beam 5 and the triangular area 6 respectively. preforms, and then they are assembled to end up with a fiber preform for a fiber-reinforced resin-based composite wing box.

Step 5: Put the prepared fiber preform of the fiber-reinforced resin-based composite material wing box into the mold, and then position and close the mold.

Step 6: Vacuumize. When the vacuum degree reaches the requirement of -0.1, start to inject resin into the mold to fill the gap between the fiber preforms of the fiber-reinforced resin-based composite material wing box, and wait for the resin to fill the fiber-reinforced resin-based composite material wing box. After the gap of the fiber preform, the temperature is raised and cured according to the curing process regulations of the resin.

Wherein, the "resin" described in step six can be epoxy resin, polyimide, thermoplastic polyurethane, polyamide, polyphenylene sulfide, polyarylether ketone or polyvinyl alcohol; "Curing process specification" refers to the regulation of relevant process parameters during the entire curing process of the resin, and each type of resin has a matching curing process specification. For the RTM overall molding process, the pressure of injecting resin into the mold is controlled above 0.5MPa.

Step 7. After curing, cool the mold to room temperature, open the mold, and take out the cured fiber-reinforced resin-based composite material wing box. At this time, the inner cavity of the fiber-reinforced resin-based composite material wing box still has a central water-soluble Sex core 12.

Step 8: After dissolving the central water-soluble core 12 from the inner cavity of the fiber-reinforced resin-based composite material wing box with water, the fiber-reinforced resin-based composite material wing box is finally obtained.

Claims (1)

1. the integral forming method of a fiber-reinforced resin matrix compound material wing box, it is characterized in that: the structural design scheme first determining fiber-reinforced resin matrix compound material wing box, then according to the structural design scheme determination mould program of fiber-reinforced resin matrix compound material wing box, ready mould is utilized to prepare water-soluble core, prepare the perform manufacturing of fiber-reinforced resin matrix compound material wing box, the perform manufacturing of the fiber-reinforced resin matrix compound material wing box prepared is put into mould and located matched moulds, vacuumize afterwards, note resin and elevated cure, after to be solidified, the fiber-reinforced resin matrix compound material wing box with water-soluble core is taken out in die sinking, after finally water-soluble core being dissolved from the inner chamber of fiber-reinforced resin matrix compound material wing box with water, finally obtain fiber-reinforced resin matrix compound material wing box, concrete implementation step is as follows:

Step one, determine the structural design scheme of fiber-reinforced resin matrix compound material wing box:

Wherein, structural design scheme described in step one needs to design according to technical indicator, the structure of fiber-reinforced resin matrix compound material wing box is made up of one or more cavity, and each cavity is designed to prismatic or variable cross-section as required, the shape of cross section of each cavity is trapezoidal, parallelogram, triangle or the closed outline shape becoming radian, the shape of each cavity is arbitrary, and fiber-reinforced resin matrix compound material wing box local has or without strengthening rib strip and ribs; The fiber-reinforced resin matrix compound material wing box chosen is the uiform section structure of single cavity, and cavity geometry is rectangle, and fiber-reinforced resin matrix compound material wing box is made up of left C-shaped beam, upper covering, right C-shaped beam, lower covering, inner rectangular box beam and trigonum;

Step 2, design determination mould program according to fiber-reinforced resin matrix compound material wing box, prepare the mould of fiber-reinforced resin matrix compound material wing box and prepare the mould of water-soluble core:

Wherein, water-soluble core described in step 2 is made up of the water-soluble material of one, this material is Powdered, be poured into after adding mixing in dies cavity, the water-soluble core the same with mold shape can be obtained after being dried by water, water-soluble core has stable physical property and chemical property under room temperature and hot environment, when preparing fiber-reinforced resin matrix compound material wing box, under the hot environment of resin curing process, water-soluble core can keep designing external form, core can not decompose or damage, after resin solidification, after being cooled to room temperature, water-soluble core can by water-soluble solution, the mould preparing fiber-reinforced resin matrix compound material wing box described in step 2 is by patrix, left C-shaped core, counterdie, right C-shaped core, sealing strip, central authorities' water-soluble core, left end cap and right end cap composition, patrix and upper covering are fitted, left-handed form core and left C-shaped beam are fitted, counterdie and lower covering are fitted, right C-shaped core and right C-type beam are fitted, central authorities' water-soluble core and inner rectangular box beam inner surface are fitted, upper die and lower die can by left C-shaped core, right C-shaped core, left end cap and right end cap location, central water-soluble core can be located by left end cap and right end cap, sealing strip is made up of silica gel material, there is sealing and elasticity relatively preferably, whole set of die is sealed, the mould preparing water-soluble core described in step 2 is by rear end cap, central rigid skeleton, drive end bearing bracket, epipleural, left plate, lower side panel and right plate, wherein epipleural, left plate, lower side panel and right plate assemble up formation rectangular enclosure, be used for preparing central water-soluble core, central rigid skeleton plays booster action to central water-soluble core, prevent by central water-soluble core conquassation in matched moulds process, central rigid skeleton is by rear end cap and drive end bearing bracket location,

Step 3, prepare water-soluble core:

Wherein, after the water-soluble core described in step 4 completes core processing according to the moulding process of water-soluble core, be coated with last layer nano material diaphragm on its surface and carry out sealing pores, and stick one deck poly tetrafluoroethylene, ensure whose surfaces fineness, prevent resin from infiltrating water-soluble core simultaneously;

Step 4, according to design laying scheme paving cover fiber cloth, the setting agent of employing between layers of fiber cloth is shaped, and prepares the perform manufacturing of fiber-reinforced resin matrix compound material wing box:

Wherein, the laying scheme of the design described in step 4 is the laying scheme of balance and symmetry, and the index that the concrete laying number of plies, laying angle and laying ratio will realize as required designs; The fiber of the fiber cloth described in step 4 is carbon fiber, glass fibre, Kevlar fiber, boron fibre or string; Setting agent described in step one is a kind of macromolecular material, need the compatibility had with the resin for the preparation of fiber-reinforced resin matrix compound material wing box, playing styling by applying a small amount of setting agent between scrim cloth, making the perform manufacturing of fiber-reinforced resin matrix compound material wing box have certain globality; Because fiber-reinforced resin matrix compound material wing box is made up of left C-shaped beam, upper covering, right C-shaped beam, lower covering, inner rectangular box beam and trigonum, when preparing the perform manufacturing of the fiber-reinforced resin matrix compound material wing box needs first prepare respectively left C-type beam, on covering, right C-type beam, lower covering, inner rectangular box beam and trigonum perform manufacturing, they assemble again afterwards, finally obtain the perform manufacturing of fiber-reinforced resin matrix compound material wing box;

Step 5, the perform manufacturing of the fiber-reinforced resin matrix compound material wing box prepared is put into mould, then locates matched moulds:

Step 6, to vacuumize, when vacuum reaches requirement-0.1, start the gap of perform manufacturing resin by injection fiberfill fibers in mould being strengthened polymer matrix composites wing box, after treating the gap of the perform manufacturing of the full fiber-reinforced resin matrix compound material wing box of resin filling, carry out elevated cure according to the curing process code of resin;

Wherein, the resin described in step 6 is epoxy resin, polyimides, thermoplastic polyurethane, polyamide, polyphenylene sulfide, PAEK or polyvinyl alcohol; Refer to the regulation to resin related process parameters in whole solidification process in the curing process code described in step 6, the resin of often kind of model is all to there being the curing process code matched with it; For RTM integral forming technique, in mould, the Stress control of resin by injection is at more than 0.5MPa;

After step 7, solidification, by mold cools down to room temperature, open mould afterwards, take out and have cured shaping fiber-reinforced resin matrix compound material wing box, still with central water-soluble core in the inner chamber of now fiber-reinforced resin matrix compound material wing box;

Step 8, with water, central water-soluble core is dissolved from the inner chamber of fiber-reinforced resin matrix compound material wing box after, finally obtain fiber-reinforced resin matrix compound material wing box.