CN113547772B

CN113547772B - Preparation method of fan blade with mixed structure

Info

Publication number: CN113547772B
Application number: CN202110637171.5A
Authority: CN
Inventors: 周海丽; 李超; 郭洪伟; 孙方方; 赵宪涛; 曹源; 张立泉; 赵谦
Original assignee: Sinoma Science and Technology Co Ltd; Nanjing Fiberglass Research and Design Institute Co Ltd
Current assignee: Sinoma Science and Technology Co Ltd; Nanjing Fiberglass Research and Design Institute Co Ltd
Priority date: 2021-06-08
Filing date: 2021-06-08
Publication date: 2022-09-16
Anticipated expiration: 2041-06-08
Also published as: CN113547772A

Abstract

The invention discloses a preparation method of a fan blade with a mixed structure, wherein the fan blade comprises a prefabricated composite material part (20) formed by an opening area (22) and a pure composite material area (21), a metal front edge part (30) and a sewing line (40) for connecting the composite material part (20) and the metal front edge part (30), the opening area (22) is arranged on one side of the composite material part (20), and the metal front edge part (30) and the composite material part (20) are sewn and connected by the sewing line (40) after the metal front edge part (30) is inserted into the opening area (22) to obtain the fan blade. According to the invention, the metal and the composite material are combined by fiber sewing, so that a single glue joint connection mode is avoided, the bonding strength between the metal and the composite material is increased, RTM integrated manufacturing and forming of the blade can be realized, the integrated preparation of a metal sandwich structure and a three-dimensional woven prefabricated body is realized, the weight reduction of the blade is realized, and the requirement on impact resistance is met.

Description

Preparation method of fan blade with mixed structure

Technical Field

The invention belongs to the technical field of aero-engines, and particularly relates to a method for manufacturing a fan blade with a mixed structure.

Background

With the improvement of the fuel economy requirement of modern commercial aircraft engines, the light high-strength composite material is more and more widely applied to the aircraft engines. For components at the cold end of an engine, such as fan blades, fan outlet guide blades, fan containing casings and the like, foreign mature aircraft engine manufacturers have realized that parts or all of the components are made of resin-based composite materials, and the weight reduction effect of the components brings great improvement on fuel efficiency for airlines.

The resin-based composite fan blade is sufficiently impact resistant (bird strike resistance) to withstand the ingestion of sand or birds encountered during engine operation. The traditional solution is to bond a metal stiffener to the leading edge of the composite fan blade to enhance its bird strike resistance. At present, due to the limitation of processing capacity in China, the manufacturing process of the metal reinforcing edge cannot meet the precision requirement, and meanwhile, the processing cost is extremely high, so that the large-scale batch production of commercial aircraft engines in China cannot be met.

Patent CN108930664A discloses a hybrid structure aircraft engine fan blade, the blade comprising a metal leading edge panel and a composite material portion, the metal leading edge panel and the composite material portion being combined in an interface coupling (which may be a seam) manner. However, the patent does not disclose the preparation method of the three-dimensional woven preform of the composite material reinforcement and the manner of forming the opening, and does not disclose the specific sewing and connecting process, and the metal leading edge panel and the composite material part are realized by directly butt-jointing and sewing the interface, namely, one side of the composite material and one side of the metal are in a non-symmetrical integral structure due to the large difference of the two materials, so that large tensile and shearing forces are formed at the interface of the composite material and the metal when the metal part is impacted.

Disclosure of Invention

The invention aims to provide a preparation method of a fan blade with a mixed structure and good integrity.

The technical solution to achieve the above object is as follows:

a method of making a hybrid construction fan blade, the blade comprising a composite portion, a metallic leading edge portion and a seam connecting the composite portion and the metallic leading edge portion,

and arranging an opening area on one side of the composite material part, inserting the metal front edge part into the opening area, and then sewing and connecting the metal front edge part and the composite material part by using a sewing line to obtain the fan blade.

Further, the metallic leading edge portion includes a metallic solid leading edge and a sandwich region, and the composite portion includes an open region and a pure composite region.

Further, the method comprises the steps of:

the first step is as follows: determining a solid metal front edge, an opening area and a pure composite material area of the blade based on the fan blade model with the mixed structure, and carrying out grid division on the composite material area;

the second step is that: designing and preparing a prefabricated part of the composite material corresponding to the opening area and the pure composite material area;

the third step: inserting the sandwich area of the metal front edge part into the opening area to form composite material prefabricated body sandwich metal, and positioning the prefabricated body;

the fourth step: the metal front edge part and the three-dimensional woven prefabricated body are connected by sewing threads;

the fifth step: and (3) molding the sewn prefabricated sandwich metal blade by adopting a liquid molding process, filling liquid resin into the mold, fully impregnating the composite material part of the blade by the resin, curing and demolding to complete integrated molding.

Further, the grid division characteristics in the first step are as follows:

dividing the blade along the radial direction of the blade according to the adjacent weft yarn pitch dw which is 10/Mw, and dividing the blade along the chord direction of the blade according to the adjacent warp yarn pitch dj which is 10/Mj, wherein Mw is the weft yarn arrangement density, Mj is the warp yarn arrangement density, the grid is positioned in a composite material sandwich metal area and defined as an open area, and the grid is positioned in a pure composite material area and defined as a pure composite material area.

Further, the second step specifically includes:

(1) the prefabricated body adopts a three-dimensional woven structure with interlayer connection, such as a three-dimensional angle interlocking structure, a three-dimensional orthogonal structure and other variable weave structures with interlayer connection, and preferably adopts a structure with the same number of layers of warp and weft yarns, so that the uniform conversion from an integral area to an opening area is facilitated;

(2) determining the interweaving times of yarns at corresponding positions in the opening area and the pure composite material area according to the number of the grid intersections of the opening area and the pure composite material area, wherein each grid intersection corresponds to one interweaving;

(3) the pure composite material area is integrated with the prefabricated body correspondingly, and the layers in the thickness direction are connected by yarns to form a whole;

(4) the opening area is divided into an upper part and a lower part corresponding to the prefabricated body, and no fiber penetrates between the two parts to form an opening, so that the metal sandwich can be arranged between the upper part and the lower part of the prefabricated body;

(5) part or all of the yarns of the opening area preform are derived from the pure composite area preform;

(6) the thickness of the prefabricated part is changed through yarn reduction or a yarn specification change form, so that net size profiling is achieved, meanwhile, structural and yarn specification combination is carried out according to the requirement of rigidity and strength of the blade, and bird impact resistance of the blade is improved.

Furthermore, the yarns of the prefabricated body in the opening area in the step (5) are derived from the yarns at the inner side of the prefabricated body in the pure composite material area, so that the problem that the yarns are reduced from the pure composite material area to the sandwich area and are difficult to trim in the inner layer is solved.

Further, the sandwich region of the metal front edge part is provided with a plurality of through holes.

Further, the fourth step adopts a mode of combining along the radial direction and the chord direction, wherein the sewing is carried out along the radial direction near the metal front edge, and the sewing is carried out along the chord direction in the region far away from the metal front edge.

A fan blade with a mixed structure is prepared by the method.

Compared with the prior art, the invention has the beneficial effects that:

(1) according to the blade, the metal and the composite material are combined through fiber sewing, a single glue joint connection mode is avoided, the bonding strength between the metal and the composite material is increased, RTM (resin transfer molding) integrated manufacturing and forming of the blade can be realized, the weight of the blade is reduced, and the requirement on the shock resistance is met;

(2) the invention can realize the integrated preparation of the metal sandwich structure and the three-dimensional woven prefabricated body;

(3) the irregular local layered opening of the special-shaped three-dimensional woven preform is integrally woven by changing the yarn path;

(4) the prefabricated body starts to reduce yarn from the upper surface and the lower surface, and the yarn does not need to be reduced on the inner side of the layering area, so that the trimming is more convenient.

Drawings

FIG. 1 is a schematic view of a hybrid fan blade.

FIG. 2 is an exploded view of a hybrid fan blade.

Fig. 3 is a schematic sectional view taken along line a-a in fig. 2.

FIG. 4 is a schematic view of the preform structure corresponding to section A-A in FIG. 2.

Fig. 5 is a schematic cross-sectional view of B-B in fig. 2.

FIG. 6 is a schematic view of the preform structure corresponding to section B-B in FIG. 2.

Fig. 7 is a schematic cross-sectional view of C-C in fig. 1.

Description of reference numerals:

10-hybrid fan blades; section 11-C-C; 20-a composite portion; 21-a pure composite region; 22-an open area; section 23-A-A; section 24-B-B; 30-a metallic leading edge portion; 31-the corresponding stitching through hole of the metal front edge; 32-metal solid leading edge; 40-a suture; the section 230-A-A corresponds to a three-dimensional woven preform part; the section 231-A-A corresponds to the warp yarns of the three-dimensional woven preform; the 232-A-A section corresponds to weft yarns of the three-dimensional woven preform; the section 240-B-B corresponds to a three-dimensional woven preform part; the section 241-B-B corresponds to the warp yarns of the three-dimensional woven preform; the section 242-B-B corresponds to the weft yarns of the three-dimensional woven preform.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

Examples

Referring to fig. 1-7, a hybrid fan blade 10 is described that includes a composite portion 20 reinforced with a three-dimensional woven preform, a metallic leading edge portion 30, and a seam 40 connecting the metallic and composite portions. Wherein the surface of the metal of the mixed zone has dense stitching through holes 31 for threading sutures 40 to form a bond with the preform. The preparation process comprises the following steps:

the first step is as follows: determining a blade metal solid front edge 32, a composite material sandwich metal region 22 and a pure composite material region 21 based on a fan blade model with a metal and composite material mixed structure, and performing grid division on the composite material region, wherein the warp density is Mj and 8 pieces/cm, the weft density is Mw and 4 pieces/cm, the weft yarn interval of radial arrangement of the blades is dw and 10/Mw and 10/4 and 2.5mm, the chord-direction adjacent warp yarn interval of the blades is dj and 10/Mj and 10/8 and 1.25mm, grid lines are arranged at intervals of 2.5mm in the radial direction and are arranged at intervals of 1.25mm in the chord direction, and the intersection points of mutually perpendicular grid lines are the interweaving points of the yarns. The area of the grid in the composite sandwich metal is defined as an open area 22, and the area of the grid in the pure composite sandwich metal is defined as a complete area 21.

The second step is that: designing and preparing a composite material sandwich metal area and a prefabricated part of a pure composite material area corresponding to the composite material, wherein the prefabricated part is characterized in that:

referring to fig. 3, which is a cross-section a-a 23 along the radial direction of the composite material 20, and fig. 4, which is a cross-section a-a corresponding to the preform structure 230, the preform of this example employs a varying three-dimensional angle interlocking woven structure having the same number of layers of warp yarns 231 and weft yarns 232, which facilitates uniform transition from the unitary region to the open region. The thickness of the prefabricated body can be changed through yarn reduction or a yarn specification change form, so that net size profiling is achieved, the thickness is reduced in the yarn reduction mode, the thickness of the structure 230 is gradually reduced from the tenon of the blade to the tenon of the blade tip, and the number of layers of yarns is also gradually reduced. The structure 230 is divided into regions a1, a2, A3 and a4, wherein the regions a1 and A3 correspond to the cells in the full area 21 as pure composite regions and the regions a2 and a4 correspond to the cells in the open area 22 as composite and metal mixed regions. The yarns in the A1 and A3 areas form layer-by-layer connections in the thickness direction, so that a unitary structure is formed in the thickness. The areas A2 and A4 form an opening in the thickness center by changing the yarn path, and reserve a position for the metal sandwich, wherein the warp yarn 231 in the area A2 is derived from the area A1, so that the area A2 and the area A1 are integrated, particularly preferably the weft yarn in the area A2 is derived from the center of the area A1, and similarly, the warp yarn 231 in the area A4 is derived from the area A3, so that the area A4 and the area A3 are integrated, particularly preferably the weft yarn in the area A4 is derived from the center of the area A3, thereby avoiding the problem that the variable thickness yarn is difficult to trim in the inner layer.

The structural characteristics of the preform are also illustrated along a radial section B-B of the blade, fig. 5 is a cross-sectional view of the composite material corresponding to section B-B, which corresponds to a schematic cross-sectional view of the preform shown in fig. 6. Preform 240 includes composite-to-metal mixed region B1 and pure composite region B2, where the B1 grid is in the open region and the B2 grid is in the full region. The section consists of warp yarn 241 and weft yarn 242, the yarns are connected layer by layer on the thickness in a pure composite material area B2, an opening is reserved in an area B1, so that a metal sandwich is inserted, the transition from an area B2 to an area B1 is realized, the weft yarn in the area B1 is derived from a main body in the area B2, and the weft yarn in the area B1 is preferably derived from the central yarn in the area B2, and the problem that the yarns are added and reduced due to the change of the thickness and are generated in the inner layer, so that the trimming is difficult can be avoided.

The third step: and inserting metal into the opening area of the preform to form sandwich metal of the composite material preform, positioning the preform by using a twisting tool, wherein the positioning method can be the tool positioning method disclosed in patent CN 111037938A.

The fourth step: the prefabricated body and the sandwich metal are sewed and connected by adopting a sewing thread, and the sewing process has the following characteristics:

the sewing mode can adopt common sewing, lock type sewing, chain type sewing and corresponding improved sewing modes, preferably, in order to avoid fiber damage and increased sewing difficulty caused by the fact that the sewing thread passes through the same through hole for multiple times, a simple common sewing mode is adopted;

the suture line can be made of aramid fiber, carbon fiber, glass fiber, metal wire and other raw materials, preferably, the fiber with high shear strength and large elongation at break is selected near the front edge of the blade, such as the aramid fiber, wherein the suture line is twisted to reduce suture damage;

the sewing direction is as follows: the method adopts a mode of combining along a radial direction and a chord direction, wherein the sewing is performed along the radial direction close to the metal front edge, so that the crack of the sewing interface caused by bird strike is favorably prevented from expanding along the chord direction, and the sewing is performed along the chord direction in an area far away from the metal front edge, so that the crack of the sewing interface caused by bird strike is favorably prevented from expanding along the chord direction;

in the embodiment, the stitching method adopts common stitching, and the stitching thread 40 passes through the stitching needle, and the stitching needle passes through the preform and the metal through hole 31, so that the preform and the metal are stitched and fixed into a whole. The suture line is formed by combining aramid fibers and carbon fibers, 1 column close to the metal front edge is made of aramid fibers with excellent shearing resistance, and the rest columns are made of carbon fibers, wherein the fibers reduce suture damage through twisting.

The stitching directions are combined along a radial direction and a chord direction as shown in fig. 1, wherein stitching is performed along the radial direction in a first row close to the metal front edge, so that the stitching interface is favorably prevented from being cracked and expanded along the chord direction due to bird strike, and stitching is performed along the chord direction in a region far away from the metal front edge, so that the stitching interface is favorably prevented from being expanded along the chord direction due to bird strike, wherein the spanwise stitching is schematically shown in fig. 7, namely a chord direction section C-C of the blade.

The fifth step: the sewed prefabricated sandwich metal blade is molded by adopting a liquid molding technology (such as a resin transfer molding process), liquid resin is filled into a mold, and after the blade composite material part is fully impregnated by the resin, the blade composite material part is cured by a specific process and is demoulded, so that integrated molding is completed.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method of making a hybrid construction fan blade preform comprising a composite portion (20), a metallic leading edge portion (30) and a seam (40) connecting the composite portion (20) and the metallic leading edge portion (30),

arranging an opening area (22) on one side of the composite material part (20), inserting the metal front edge part (30) into the opening area (22), and sewing and connecting the metal front edge part (30) and the composite material part (20) by using a sewing line (40) to obtain the fan blade preform;

the metallic leading edge portion (30) comprises a metallic solid leading edge (32) and a core region, the composite material portion (20) comprises an open area (22) and a pure composite material region (21);

the method comprises the following steps:

the first step is as follows: determining a blade metal solid leading edge (32), an opening area (22) and a pure composite material area (21) based on a fan blade model with a mixed structure, and meshing the composite material area (21);

the second step is that: designing and preparing a preform part of the composite material corresponding to the open area (22) and the pure composite material area (21);

the third step: inserting the sandwich region of the metal front edge part (30) into the opening region (22) to form composite material prefabricated body sandwich metal, and positioning the prefabricated body;

the fourth step: the metal front edge part (30) and the three-dimensional woven prefabricated body are connected by sewing by using a sewing thread (40);

the grid division characteristics in the first step are as follows:

dividing the blade along the radial direction of the blade according to the adjacent weft yarn spacing dw =10/Mw, and dividing the blade along the chord direction of the blade according to the adjacent warp yarn spacing dj =10/Mj, wherein Mw is the weft yarn arrangement density, Mj is the warp yarn arrangement density, the grid is positioned in a composite material sandwich metal area to be defined as an open area (22), and the grid is positioned in a pure composite material area to be defined as a pure composite material area (21);

the second step specifically comprises:

(1) the prefabricated body adopts a three-dimensional woven structure with interlayer connection;

(2) determining the interweaving times of the yarns at the corresponding positions in the opening area (22) and the pure composite material area (21) according to the number of the grid intersections of the opening area (22) and the pure composite material area (21), wherein each grid intersection corresponds to one interweaving;

(3) the pure composite material area (21) is of an integral structure corresponding to the prefabricated body, and all layers in the penetrating thickness direction are connected by yarns to form a whole;

(4) the opening area (22) is divided into an upper part and a lower part corresponding to the prefabricated body, and no fiber penetrates between the two parts to form an opening, so that the metal sandwich can be arranged between the upper part and the lower part of the prefabricated body;

(5) part or all of the yarns of the preform in the open area (22) originate from the preform in the pure composite area (21);

2. The method for producing a hybrid fan blade preform as defined in claim 1 wherein step (1) employs a three-dimensional woven structure having the same number of warp and weft yarn layers.

3. The method for manufacturing a hybrid fan blade preform according to claim 1, wherein in step (5) the open area (22) preform yarn is derived from a pure composite region (21) preform inside yarn.

4. Method for producing a hybrid fan blade preform according to claim 1, characterised in that the sandwich region of the metal leading edge portion (30) is provided with a plurality of through holes (31).

5. The method of manufacturing a hybrid fan blade preform as defined in claim 1 wherein the fourth step is a combination of radial and chordwise seams, wherein the seams are radially sewn near the metal leading edge and chordwise seams are sewn in regions away from the metal leading edge.

6. A hybrid construction fan blade preform, characterized in that the blade preform is produced by the method of any of claims 1-5.