CN113858650A

CN113858650A - Method for manufacturing composite annular parts

Info

Publication number: CN113858650A
Application number: CN202010620464.8A
Authority: CN
Inventors: 张璇; 孔维夷; 张建
Original assignee: AECC Commercial Aircraft Engine Co Ltd
Current assignee: AECC Commercial Aircraft Engine Co Ltd
Priority date: 2020-06-30
Filing date: 2020-06-30
Publication date: 2021-12-31

Abstract

The object of the present invention is to provide a method for manufacturing composite loop elements which replaces the traditional technique of laser projection combined with tracer yarns and which allows an accurate deformation of the fabric to be achieved. In order to achieve the above object, a method for manufacturing an endless member of composite material, which comprises installing a positioning pin on a core mold, the positioning pin being positioned to correspond to crossing points of tracer yarns in a radial direction and a weft direction of a preform, the positioning pin penetrating the crossing points of the tracer yarns on the preform when the preform is wound on the core mold, and adjusting positions of warp yarns and weft yarns of the preform which does not satisfy a design deformation to correct the positions of the yarns; after the winding of the preform is completed, at least a portion of the positioning pin is retained in the preform as an interlaminar reinforcing phase to improve the interlaminar strength of the preform.

Description

Method for manufacturing composite annular parts

Technical Field

The present invention relates to casings for gas turbines and turbofan aircraft engines, and in particular to a fan-containing casing therein.

Background

In aircraft engines and gas turbines, there are a large number of blades rotating at high speed, and the rotating blades may come off in the event of foreign object impact, process defects, and the like. Therefore, the engine casing is required to have good containment, and high-speed and high-energy fragments are ensured not to penetrate through the casing, so that the damage to equipment and personnel is caused. The large unbalanced load of the rotor of the engine after the blades are flied off can cause the engine to generate continuous vibration before stopping, and the casing is still required to maintain certain structural integrity and not be disassembled.

Meanwhile, the engine case is large in size, and the weight of the engine case has a significant influence on the total weight of the engine, so that the efficiency of the engine is influenced. Carbon fiber composite materials are commonly used for low-temperature end casings in new-generation commercial engines. Patent EP1674244 proposes the use of a triaxial woven preform, a resin-added liquid moulding process to produce fan-containing casings of equal thickness. EP1674671 proposes a fan-housing casing of variable thickness, the reinforcing phase of the casing composite core being a circumferentially aligned, multi-layered superimposed braid, the other composite layers being obtained from a helically wound braid. Patent US8322971B2 proposes a composite material containing casing, which is obtained by processing a variable-thickness fiber preform by a three-dimensional weaving method, then winding the fiber preform on a mandrel in a laminated manner to obtain a casing preform, and then molding the casing preform by resin liquid.

When the fiber fabric is used for manufacturing a composite material member with a large curvature, the fiber fabric needs to be twisted, wound, compacted and the like to meet the forming requirement, and when the twisting and winding are carried out, the conventional laser projection and tracer yarn combined technology is generally adopted to complete the deformation of the fiber fabric. When the tracer yarn does not match with the laser projection position, the deviation value can only be obtained through manual measurement, then the tracer yarn or the prefabricated body of next fabric are adjusted according to the deviation value, and real-time adjustment can not be carried out on the current prefabricated body.

Disclosure of Invention

The object of the present invention is to provide a method for manufacturing composite loop elements which replaces the traditional technique of laser projection combined with tracer yarns and which allows an accurate deformation of the fabric to be achieved.

In order to achieve the above object, a method for manufacturing an endless member of composite material, which comprises installing a positioning pin on a core mold, the positioning pin being positioned to correspond to crossing points of tracer yarns in a radial direction and a weft direction of a preform, the positioning pin penetrating the crossing points of the tracer yarns on the preform when the preform is wound on the core mold, and adjusting positions of warp yarns and weft yarns of the preform which does not satisfy a design deformation to correct the positions of the yarns; after the winding of the preform is completed, at least a portion of the positioning pin is retained in the preform as an interlaminar reinforcing phase to improve the interlaminar strength of the preform.

In one or more embodiments, the locating pins are configured to include pins and a core mold connector, the core mold connector having a material with a melting temperature below the molding resin injection temperature of the composite annulus, the pins being attached to the core mold using the core mold connector, the pins penetrating the intersections of the tracer yarns on the preform;

after the winding of the fiber preform is completed, the mold is closed, the mold is heated to perform the injection of the molding resin, and in the heating process, the core mold connecting member is softened until being melted, the molten liquid flows into the core mold, and the pins remain in the fiber preform, connecting each layer of the preform after the laying.

In one or more embodiments, the pin is a hollow structure, the mandrel connector is a T-shaped pin, and the T-shaped pin is screwed into the pin and is embedded into the groove of the mandrel; the core mold further comprises a liquid storage tank communicated with the groove, and the liquid storage tank is set to contain liquid after the T-shaped nails are melted.

In one or more embodiments, the pin is metal, resin, rubber, or cured prepreg.

In one or more embodiments, the composite ring member is a fan containment case.

In one or more embodiments, the step of winding and laying the preform on the core mold includes continuously winding a planar dummy preform, which is flattened in a rectangular shape and is woven by a weaving process, on a core mold, the length direction of the preform being a warp direction of the preform, the width direction being a weft direction of the preform, the length direction including a start end and a tail end, the start end and the tail end being located at both ends of the preform, and the thickness gradually decreasing toward the ends.

In one or more embodiments, the length of each of the start and tail ends is set to an arc length no less than 10 ° of the outer diameter of the composite annular member.

In one or more embodiments, the preform is a 2-dimensional fabric or a 3-dimensional fabric fabricated by weaving, or stitching.

The beneficial effects of the foregoing technical scheme are:

by arranging the tracer yarn cross point positioning pin on the core mould for forming the composite annular piece, the positions of warp and weft are corrected when the prefabricated piece is wound, so that the winding deformation precision control and design requirements of the prefabricated piece are met, real-time adjustment of the warp and the weft can be realized by the method, at least one part of the positioning pin is kept in the prefabricated piece as an interlayer reinforcing phase, the capability of keeping the structural integrity of the composite annular piece under an impact load is further improved, and the safety is improved.

Drawings

The above and other features, properties and advantages of the present invention will become more apparent from the following description of the embodiments with reference to the accompanying drawings, in which:

FIG. 1 is a flow diagram of a method of manufacturing a composite annular part.

Fig. 2 is a schematic view of completing winding of a preform on a core mold.

Fig. 3 is a schematic view of the structure of the embedded positioning pin.

FIG. 4 is a schematic illustration of a locating pin adjusting tracer yarn deflection.

Fig. 5 is a schematic view of the embedded alignment pin being coupled to the core mold.

Fig. 6 shows the state of the positioning pin before the temperature of the mold rises.

FIG. 7 is a schematic view of the insert locating pin partially melted after the mold is heated.

Detailed Description

The following discloses many different embodiments or examples for implementing the subject technology described. Specific examples of components and arrangements are described below to simplify the present disclosure, but these are merely examples and do not limit the scope of the invention. For example, if a first feature is formed over or on a second feature described later in the specification, this may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact. Additionally, reference numerals and/or letters may be repeated among the various examples throughout this disclosure. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Further, when a first element is described as being coupled or coupled to a second element, the description includes embodiments in which the first and second elements are directly coupled or coupled to each other, as well as embodiments in which one or more additional intervening elements are added to indirectly couple or couple the first and second elements to each other.

In the embodiments described below, the method of manufacturing the composite annular member will be described by taking a housing casing of an engine as an example.

Figure 1 shows a flow chart of a method of manufacturing a composite annular part. In step 31, a flat fiber preform or a mold-proof preform of the casing is manufactured or provided. Carbon fiber, glass fiber, Kevlar fiber, polyimide fiber, SiC fiber, etc. can be used to make 2-or 3-dimensional preforms such as woven, knitted, stitched, etc. In one embodiment, the dummy preform is flattened to approximate a rectangle, and is woven by a weaving process. The length direction of the preform is the warp direction of the preform, the width direction is the weft direction of the preform, the length direction comprises a starting end 15 and a tail end 16, and the positions of the starting end 15 and the tail end 16 are shown in figure 2.

Referring to FIG. 2, in step 32, a flat fiber preform is wound onto a mandrel, the winding including flapping, winding, and possibly twisting, and the preform is wound onto a rigid mandrel 1 with a number of windings equal to or greater than 2, and the embodiment shown employs 3 layers of

preforms

10, 17, 18. The starting end 15 and the tail end 16 are positioned at two ends of the prefabricated body 6, the lengths of the starting end and the tail end are not less than the arc length of 10 degrees of the outer diameter of the casing, the thickness of the prefabricated body is gradually reduced towards the end, and the step height of the end is reduced, so that the possibility of interface failure caused by stress concentration at the position is reduced. Between the starting end 15 and the tail end 16 there may be a preform zone corresponding to several turns of the wound casing. The thickness of each area of the prefabricated body is changed according to the requirement by adjusting the layer number of the yarns during weaving, so that the imitated prefabricated body imitating the contour and the thickness distribution of the casing is realized.

With continued reference to FIG. 2, at step 33, the locating pins 7, 8, 9 are inserted through the preform warp and weft tracer yarn crossover points and the locations of the crossover points are then adjusted. Only resin exists among the

prefabricated bodies

10, 17 and 18 of each layer, the strength among the layers is weak, and delamination is easy to occur when the blade is impacted. Specifically, the containment case is prepared by winding the preform, with only the matrix material present at the interface of the different preform layers for joining. Once the blade is subjected to the blade falling load, the base material at the interface fails under the action of the interlayer stress, so that the interface is debonded, different layers begin to separate, particularly the tail end of the winding prefabricated body at the outer side of the casing belongs to a free end, and the interface is more likely to be debonded from the inner layer after the impact load of the blade falling, so that large-area interlayer debonding is caused. After the blade falls off, the engine can generate severe vibration for a period of time, the influence range of interface failure and debonding is continuously enlarged, and finally the rigidity of the casing is seriously reduced, even the casing is disassembled, and great threat is caused to the safety of the human body. As will be understood from the following description, at least a part of the positioning pin remains in the preform as an interlayer reinforcing phase after the winding of the preform is completed, to improve the interlayer strength of the preform, and thus the problem can be solved.

As shown in fig. 4, the core mold is provided with positioning pins 7, 8, 9, and the intersections 4'2', 3'2', 5'2' are designed corresponding to the tracer yarns. Fig. 4 shows a part of the preform 6, the design locations 20 and the tracer yarns 21 being shown in different line types, the point reference numbers being combined with the warp and weft reference numbers to indicate the respective warp and weft intersections, e.g. the intersections 4'2', 3'2', 5'2' are the points where the ideal warp 4', 3', 5 'intersects the ideal weft 2', respectively, and the intersections 42, 32, 52 are the points where the

actual warp

4, 3, 5 intersects the actual weft 2, respectively. One turn 10 is wound until the starting end 15 is covered, and the positioning pins 7, 8, 9 are passed through the crossing points 42, 32, 52 of the warp and weft tracer yarns on the preform during winding, so that the actual tracer yarn crossing points 42, 32, 52 are adjusted to the designed crossing points 4'2', 3'2', 5 '2'. The winding is continued for two

turns

17, 18, during which the pin passes through the crossing points of the warp and weft tracer yarns on the preform for 17, 18 turns, ensuring that the actual tracer yarn crossing points are at the design position until the end 16 is finished.

The dowels, which may be referred to as embedded dowels, are illustratively shown in fig. 3 and include a dowel 12 and a core connector 13, the core connector 13 having a material with a melting temperature lower than the molding resin injection temperature of the composite loop, as shown in fig. 5, the dowel 12 being attached to the core 1 using the core connector 13, as shown in fig. 6, the dowel 12 penetrating the crossing points of the tracer yarns on each

layer

10, 17, 18 of the preform.

With continued reference to fig. 3, the core mold coupling member 13 is a T-shaped nail, the pin 12 is a hollow structure, and the core mold coupling member 13 is screwed into the pin 12 while its head portion is fitted into the T-shaped groove of the core mold 1.

The pin 12 can be made of metal, resin, rubber, cured prepreg and other materials, and has a length of 1mm-300mm, a diameter of 1mm-30mm, and a thickness of 0.5mm-10 mm. The core mold connector 13 is made of a material having a melting temperature lower than the injection temperature of the casing forming resin, such as low-temperature thermoplastic resin, rubber, etc., such as polypropylene, and has a length of 1mm to 300mm, a diameter of 1mm to 30mm, and a thickness of 0.1mm to 10 mm.

The positioning pins are fixed in the grooves on the outer surface of the core mould 1, the positions of the positioning pins correspond to the crossing points of the tracer yarns in the radial direction and the weft direction of the prefabricated body, when the prefabricated body is wound on the core mould, the positioning pins penetrate through the crossing points of the tracer yarns on the prefabricated body, the prefabricated body which does not meet the design deformation is subjected to the position adjustment of warp yarns and weft yarns, and the winding amount of each tracer yarn crossing point is accurately controlled and adjusted in the radial direction and the weft direction, so that the tracer yarn position of the variable-diameter prefabricated body is kept within the designed deviation in the winding process.

Returning to fig. 1, in step 34, after the winding of the flat preform is completed, the mold is closed and the temperature is raised. And a rigid outer mold or a flexible material is used for wrapping the outer surface of the wound casing prefabricated body, and the outer surface of the casing prefabricated body and the core mold form a cavity required by liquid forming. And heating the wrapped casing preform and the mold by adopting an oven, a press, an autoclave, self-heating or other appropriate heating modes.

In step 35, the mandrel coupler or T-shaped pin is melted, the pin 12 is disengaged from the mandrel 1 and remains in the cassette preform, and the pins engage the

layers

10, 17, 18 of the preform, enhancing the inter-layer bond of the preform and increasing the inter-layer strength. When the temperature is raised until the tee melts, the molten liquid flows into the core mold. As shown in fig. 5, the core mould 1 has

reservoirs

13, 14 communicating with the T-shaped recess which receives the head of the T-shaped nail. At this point, the pins 12 are at the crossing points of the warp and weft tracer yarns on the preform, connecting the

layers

10, 17, 18 of the preform.

In step 36, a liquid resin is introduced into the cavity using a suitable liquid molding process, and the resin is cured by heating, pressurizing, evacuating or any other suitable process.

In step 37, the cured casing is demolded to complete subsequent processing.

The foregoing embodiments provide a casing manufacturing method by which the positions of the warp and weft are corrected when the preform is wound by providing tracer yarn crossing point positioning pins on a core mold for casing molding, so that the winding deformation accuracy control and design requirements of the preform are satisfied, and by which real-time adjustment of the warp and weft can be realized. Meanwhile, after winding of the fiber preform is completed, mold assembly is carried out, the temperature of the mold is raised to carry out molding resin injection, in the temperature raising process, a T-shaped nail or a core mold connecting piece inside a positioning pin is softened until the T-shaped nail or the core mold connecting piece is melted, the molten liquid flows into a liquid storage tank in a core mold groove, a pin of the positioning pin is separated from a core mold and is retained in the fiber preform, each layer of preform of the wound preform is connected, and the interlayer strength of the preform can be adjusted through the density of the positioning pin and the material of an external pin. The embedded positioning pins are adopted, the prefabricated bodies of all layers are not only connected by base materials, and the external pins of the positioning pins are connected with the prefabricated body layers and the layered parts, so that the failure probability of interfaces between all layers is reduced, the containing capacity of the casing is improved, the capacity of keeping the structural integrity of the fan containing casing under an impact load (such as FBO) is further improved, and the safety of an engine is improved.

And the casing manufacturing method is suitable for composite annular parts similar to casings. The method of retaining at least a portion of the positioning pin in the preform as the interlaminar reinforcing phase may be, in addition to the foregoing embodiments, other structures suitable for releasing the positioning pin from the core mold, such as a core mold of a block-detachable structure, and after the casing is cured, the casing is detached and then the protruding positioning pin is cut.

Although the present invention has been disclosed in terms of the preferred embodiment, it is not intended to limit the invention, and variations and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention. Therefore, any modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope defined by the claims of the present invention, unless the technical essence of the present invention departs from the content of the present invention.

Claims

1. A method of manufacturing an endless member of composite material, characterized in that a core mold is provided with positioning pins, the positions of which correspond to the crossing points of tracer yarns in the radial and latitudinal directions of a preform, and when the preform is wound on the core mold, the positioning pins penetrate the crossing points of the tracer yarns on the preform, and the preform not satisfying the design deformation is subjected to position adjustment of warp and weft yarns to correct the positions of the yarns; after the winding of the preform is completed, at least a portion of the positioning pin is retained in the preform as an interlaminar reinforcing phase to improve the interlaminar strength of the preform.

2. The method of claim 1, wherein the dowel pins are provided to include a pin and a mandrel coupler, the mandrel coupler having a material with a melting temperature lower than the molding resin injection temperature of the composite loop, the pin being attached to the mandrel using the mandrel coupler, the pin penetrating the crossing points of the tracer yarns on the preform;

3. The method of claim 2, wherein the pin is a hollow structure and the mandrel coupler is a T-shaped pin that is threaded into the pin and fits into a groove in the mandrel; the core mold further comprises a liquid storage tank communicated with the groove, and the liquid storage tank is set to contain liquid after the T-shaped nails are melted.

4. The method of claim 2, wherein the pin is metal, resin, rubber, or cured prepreg.

5. A method according to claim 1, wherein the composite annular member is a fan containing case.

6. The method of claim 1, wherein the step of winding and laying the preform on a core mold comprises continuously winding a planar dummy preform, which is flattened in a rectangular shape and is woven by a weaving process, on a core mold, the length direction of the preform being a warp direction of the preform, the width direction being a weft direction of the preform, the length direction including a start end and a tail end, the start end and the tail end being located at both ends of the preform, and the thickness being gradually reduced toward the ends.

7. The method of claim 6, wherein the starting end and the trailing end are each configured to have a length that is not less than 10 ° of an arc length of the outer diameter of the composite annular member.

8. The method of claim 1, wherein the preform is a 2-dimensional fabric or a 3-dimensional fabric fabricated by weaving, or stitching.