CN117212235A - Blade metal structure and metal sandwich type fan blade - Google Patents

Abstract

The invention provides a blade metal structure which is used for a metal sandwich type fan blade and comprises a metal core, wherein the metal core is used for being clamped by a composite substrate of the metal sandwich type fan blade, and the blade metal structure has a thickness direction and a spreading direction. The metal core has a mesh structure at the tail portion, the mesh structure having a plurality of meshes extending in the spanwise direction and being discretely distributed, the mesh structure providing rear side portions of both side surfaces of the metal core in the thickness direction and a rear end face of the metal core. The invention also provides a metal sandwich type fan blade which comprises the blade metal structure. The blade metal structure can avoid the situation that the rear end of the blade is torn due to the fact that the rigidity difference between the metal core and the composite matrix is large.

Description

Blade metal structure and metal sandwich type fan blade

Technical Field

The present invention relates to a metal sandwich fan blade, and more particularly, to a metal structure of a blade for a metal sandwich fan blade.

Background

Fan blades are one of the key components of modern aircraft engines, and there are two types of fan blades commonly used today: titanium alloy hollow fan blades and composite fan blades with a metal outer rim. The use of new structures, materials and new processes on fan blades can reduce weight and enhance their resistance to foreign object impacts, particularly bird strikes.

Chinese patent No. 108661945a discloses a fan blade having a front edge portion made of a metal material and a blade surface portion made of a metal core sandwiched between front and rear composite materials in a thickness direction of the fan blade, the metal material of the front edge portion being integrally made with the metal core. Wherein the composite material portion may be referred to as a composite matrix, herein simply as a composite matrix, and the metal material portion may be referred to as a blade metal structure comprising a metal leading edge and a metal core made of a metal material. Such fan blades that include a metallic core having a metallic leading edge and a metallic structure of the blade sandwiched by a composite body are metallic sandwich composite fan blades, referred to herein as metallic sandwich fan blades.

However, the inventors have found that since the metal core and the composite matrix differ greatly in stiffness, the blade trailing end is susceptible to tearing due to the inconsistent deformation of the two.

It is therefore desirable to provide a solution that avoids tearing due to inconsistent deformation of the two.

Disclosure of Invention

The invention aims to provide a blade metal structure which can avoid the situation that the rear end of a blade is torn due to the fact that the rigidity difference between a metal core and a composite matrix is large.

The invention also provides a blade metal structure for the metal sandwich type fan blade, the blade metal structure comprises a metal core, the metal core is used for being clamped by a composite substrate of the metal sandwich type fan blade, and the blade metal structure has a thickness direction and a spreading direction. The metal core has a mesh structure having a plurality of meshes extending in a spanwise direction and discretely distributed at a tail portion, the mesh structure providing rear side portions of both side surfaces of the metal core in a thickness direction and a rear end face of the metal core.

In one embodiment, the lattice structure includes two side panels separately provided in a thickness direction, respectively providing rear side portions of both side surfaces of the metal core. Each side panel is provided with a plurality of perforations.

In one embodiment, the lattice structure further comprises a rear rib providing a rear end face of the metal core. The rear rib is provided with a plurality of perforations.

In one embodiment, the lattice structure comprises at least one panel set. The at least one wallboard set is distributed in sequence from front to back, each wallboard set comprises a plurality of X-shaped wallboards distributed along the thickness direction, each X-shaped wallboard comprises two V-shaped wallboards which are in butt joint to form an X shape, and each V-shaped wallboard is provided with a front end and a rear end. In each panel group, two outermost V-shaped panels located outermost in the thickness direction provide a portion of both side surfaces of the metal core, respectively.

In one embodiment, the lattice structure further comprises a rear rib providing a rear end face of the metal core. The rear end of each V-shaped wall plate of the rearmost wall plate group located rearmost of the at least one wall plate group is connected to the rear rib.

In one embodiment, the lattice structure further comprises an inner rib, the at least one panel group comprises two adjacent panel groups, the two panel groups being a front panel group and a rear panel group located on a front side and a rear side, respectively, a rear end of each V-shaped panel in the front panel group being connected to a front side portion of the inner rib, and a front end of each V-shaped panel in the rear panel group being connected to a rear side portion of the inner rib.

In one embodiment, the lattice structure further comprises a front rib to which a front end of each V-shaped wall plate of the at least one wall plate group located at the foremost side is connected. The metal core includes a body portion, and the lattice structure is connected to the body portion by the front rib.

In one embodiment, the outermost V-shaped wall panel is provided with a plurality of perforations.

In one embodiment, the lattice structure of the blade metal structure is integrally formed by additive manufacturing.

The invention also provides a metal sandwich type fan blade, which comprises the blade metal structure and a composite substrate, wherein the composite substrate is connected with the grid structure of the blade metal structure through suture.

In the blade metal structure and the metal sandwich type fan blade, the hollow elastic structure formed by the grid structure can be mutually coordinated with the deformation of the composite material matrix in the bird strike process of the blade, so that the situation that the composite material matrix at the rear end of the blade is torn due to inconsistent deformation of the hollow elastic structure and the composite material matrix is avoided. Moreover, the tail part of the metal core is changed from a solid structure to a hollow elastic structure formed by a grid structure, so that the weight of the blade can be further reduced.

Drawings

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

FIG. 1 is a schematic view of an exemplary metal sandwich fan blade.

FIG. 2A is a cross-sectional view of a conventional metal sandwich fan blade taken from section line A-A of FIG. 1, showing an impending bird strike.

FIG. 2B is another cross-sectional view showing the conventional metal sandwich fan blade of FIG. 2A, showing bird body slices after impact.

FIG. 3 is a cross-sectional view illustrating an exemplary metal sandwich fan blade according to the present invention as taken from section line A-A in FIG. 1.

Fig. 4 is a partial enlarged view at B1 in fig. 3.

FIG. 5 is a schematic view of an exemplary blade metal structure according to the present invention.

Fig. 6 is a partial enlarged view at B2 in fig. 5.

Fig. 7 is a schematic view partially enlarged at B3 in fig. 6 and showing a perspective configuration thereof.

Detailed Description

The present invention will be further described with reference to the following detailed description and the accompanying drawings, in which more details are set forth in order to provide a thorough understanding of the present invention, but it will be apparent that the present invention can be embodied in many other forms than described herein, and that those skilled in the art may make similar generalizations and deductions depending on the actual application without departing from the spirit of the present invention, and therefore should not be limited in scope by the context of this detailed description.

For example, a first feature described later in this specification may be formed above or on a second feature, and may include embodiments in which the first and second features are formed in direct contact, as well as embodiments in which additional features are formed between the first and second features, such that no direct contact between the first and second features is possible. Further, where a first element is described as being coupled or combined with a second element, the description includes embodiments in which the first and second elements are directly coupled or combined with each other, and also includes embodiments in which one or more other intervening elements are added to indirectly couple or combine the first and second elements with each other.

The metal sandwich type fan blade is a novel hybrid structure (hybrid) fan blade. The metal structure of the blade is not only coated on the surface of the composite material, but also penetrates into the composite material to play a role similar to a framework. The fan blade with the configuration can more fully utilize the advantages of light weight, good fatigue resistance of the composite material, high toughness and good shock resistance of the metal material.

In the metal sandwich type fan blade, a metal core of a metal structure of the blade is inserted into a composite material matrix, so that the overall rigidity and the shock resistance of the blade are improved. When the fan blade with the mixed configuration encounters bird strike, the rear end of the blade is easy to tear due to the fact that the rigidity of the metal core and the rigidity of the composite matrix are greatly different, and the metal core and the composite matrix are deformed and are not coordinated.

Fig. 1 illustrates a top view configuration of an exemplary metal sandwich fan blade 10. The metal sandwich fan blade 10 comprises a blade metal structure 1 and a composite matrix 2, which in fig. 1 may consist of both. The metal core 11 of the blade metal structure 1 is inserted into the composite matrix 2, functioning like a "skeleton". The blade metal structure 1 has a portion which does not penetrate into the composite matrix 2 but is exposed to the outside, constituting the metal leading edge 12 of the metal sandwich fan blade 10. In fig. 1, the hatched area represents the composite matrix 2 and the white area represents the exposed portion of the blade metal structure 1, i.e. the metal leading edge 12.

Fig. 2A and 2B show a radial A-A cross section of a conventional metal sandwich fan blade 10 and bird strike indications. If the blade metal structure 1 extends from the blade leading edge L0 all the way to the blade trailing edge T0, although the blade trailing end can be protected during bird strike, additional weight is introduced, which tends to make the blade design overweight. Thus, in FIG. 1, the metal core 11a of the blade metal structure 1 is shut off at the blade trailing end P1 without extending to the trailing edge T0 to meet the blade weight-reduction requirements.

It is to be understood that the drawings are by way of example only and are not drawn to scale and should not be construed to limit the true scope of the invention.

As shown in fig. 2A, the metal sandwich-type fan blade 10 rotates in the θ direction. The bird W0 sucked by the engine in the Z direction first strikes the metal leading edge 12. That is, when the metal core fan blade 10 is impacted by a foreign object such as a bird W0, the metal leading edge 12 is first impacted, and the impact force deforms the metal core fan blade 10. Tests have shown that, due to the good toughness of the metallic material, the metallic leading edge 12 does not fracture or undergo unacceptable plastic deformation.

Thereafter, as shown in fig. 2B, the bird body W0 is cut by the metal leading edge 12 to form a bird body slice W1 that slides rearward along the blade pressure surface SP. Experiments have shown that due to the rotation of the metal sandwich fan blade 10, the slipped bird slice W1 impacts the blade trailing end P1. At the same time, the metal sandwich fan blade 10 springs back from the deformation caused by the first impact, and the inertial action causes the blade rear end P1 to have a tendency to buckle. In the conventional design, since the tail 111a of the metal core 11a is of a solid structure, the tail 111a of the metal core 11a has a large rigidity, a small deformation tendency and a quick rebound, while the composite substrate 2 at the corresponding position has a small rigidity, a large deformation tendency and a slow rebound. Under the superposition effect of bird impact and blade bending, the bird impact and the blade bending are inconsistent in deformation, and the composite material matrix is easily torn at the rear end P1 of the blade.

The present invention is intended to provide an impact stiffness coordination structure of a metal sandwich type fan blade, and to provide a fan blade developed accordingly. The tail of the metal core is changed from a solid rigid structure to a hollow elastic structure in a grid structure by providing the metal structure of the blade. The rigidity of the hollow elastic structure formed by the grid structure can be designed, so that the rigidity of the hollow elastic structure is convenient to coordinate with the rigidity of the composite matrix, the composite matrix at the rear end of the blade is prevented from being torn due to inconsistent deformation of the hollow elastic structure and the composite matrix in the bird strike process of the blade, and the impact resistance of the blade is enhanced. Moreover, the hollow elastic structure can further reduce the weight of the blade.

The blade metal structure 1 and the metal sandwich fan blade 10 provided by the present invention will be described with reference to fig. 1 and fig. 3 to 7. That is, the top view configuration of the metal sandwich fan blade 10 may also be as shown in fig. 1. In describing embodiments of the present invention, the same or similar reference numerals as those used for the conventional metal sandwich fan blade 10 and the blade metal structure 1 shown in fig. 2A and 2B are used herein to omit the descriptions of partial differences.

The blade metal structure 1 is used for a metal sandwich fan blade 10. With reference to fig. 3 and 5, the blade metal structure 1 comprises a metal core 11. The metal core 11 is intended to be clamped by the composite matrix 2 of the metal sandwich-type fan blade 10.

For convenience of description, the blade metal structure 1 has a thickness direction D1 and a spanwise direction D2, that is, a thickness direction and a spanwise direction of the metal sandwich-type fan blade 10.

The metal core 11 has a lattice structure 3 at the tail 111. The lattice structure 3 has a plurality of mesh openings 31. The plurality of mesh openings 31 extend in the spanwise direction D2 and are discretely distributed.

The lattice structure 3 provides rear side portions of both side surfaces S1, S2 of the metal core 11 in the thickness direction D1 and a rear end surface S3 of the metal core 11.

The two side surfaces S1, S2 of the metal core 11, namely the suction side surface S1 and the pressure side surface S2. The rear portions of the two side surfaces S1, S2, i.e. the suction side surface S1 and the pressure side surface S2, are at the portion of the tail 111.

It will be appreciated that the spatial relationship words "forward", "aft", "tail" are used herein to describe the relationship of one element or feature to another element or feature shown in the figures, with reference to the concepts of the leading edge L0, trailing edge T0 of the blade. Meanwhile, for convenience of description, spatial relationship words such as "upper", "lower", "left", "right", etc. may be used herein, which are described with reference to fig. 3 or 5, and are not particularly limited. For example, if the component in the figures is turned over, elements described as "on" other elements or features would then be oriented "under" the other elements or features, and the spatially relative descriptors used herein should be interpreted accordingly.

It will also be appreciated that reference herein to two directions being "perpendicular", "coincident", "parallel", etc. does not necessarily require that strict angular requirements be met in a mathematical sense, but rather that certain tolerance ranges are allowed, for example, within 20 ° of angular difference compared to what is required in a mathematical sense, whereas reference to "along" a direction means that there is at least a component in that direction, preferably within 45 ° of that direction, more preferably within 20 °, 10 ° or even 5 °. It is also understood that "plurality" herein means more than two, including two, three, four, five, etc.

The exemplary blade metal structure 1 according to the present invention is different from the conventional blade metal structure 1 in fig. 2A and 2B in that the tail 111 of the metal core 11 is modified from the solid rigid structure in fig. 2A and 2B to a hollow elastic structure constituted by the lattice structure 3.

In the blade bird strike process, the hollow elastic structure formed by the grid structures 3 in the blade metal structure 1 can be mutually coordinated with the deformation of the composite material matrix 2, so that the composite material matrix at the rear end of the blade can be prevented from being torn due to inconsistent deformation of the hollow elastic structure and the composite material matrix.

The lattice structure 3 can be regarded as being formed by the original solid structure with a cavity, and the length of the blade metal structure 1 (the metal core 11) can be not increased, so that the weight of the original structure can be reduced.

Referring in particular to fig. 4 and 6, the grid structure 3 may comprise two side panels 4. The two side panels 4 may be provided separately in the thickness direction D1, providing rear side portions of the two side surfaces S1, S2 of the metal core 11, respectively. Two side panels 4, namely an upper panel 4a (suction side panel) and a lower panel 4b (pressure side panel). Rear side portions of both side surfaces S1, S2 of the metal core 11 are separated by an upper panel 4a and a lower panel 4b in the up-down direction.

It will be appreciated that the terms "panel", "rib", "wall" as used herein are intended to refer to plate structures.

Referring particularly to fig. 7, each side panel 4 may be provided with a plurality of perforations 71. The plurality of perforations 71 may form distributed apertures, thereby facilitating a stitched connection with the composite substrate 2 by stitching through the perforations 71.

Referring particularly to fig. 4 and 6, the lattice structure 3 may further include a rear rib 51, and the rear rib 51 may provide the rear end surface S3 of the metal core 11. That is, the rear end face S3 of the metal core 11 is provided by the rear rib 51. The rear rib 51 may be provided with a plurality of perforations (not shown) so as to be connectable to the composite substrate 2 through distributed small holes.

Referring particularly to fig. 6, the lattice structure 3 may include at least one panel set 6. The at least one wall panel set 6 may be arranged one behind the other. In fig. 6, four wall plate groups 6 arranged in an array in the front-rear direction are shown. It will be appreciated that at least one wall panel 6 comprises a single wall panel 6 and that the use of "in tandem" herein is for convenience of description, i.e., that at least one wall panel 6 "in tandem" comprises a single wall panel 6 in a single distribution.

Each of the wall plate groups 6 may include a plurality of X-shaped wall plates 61, for example, six in the drawing, distributed in the thickness direction. Each X-shaped wall 61 may comprise two V-shaped walls 7 that are butted to form an X-shape, two V-shaped walls 7a being shown in the figure. Where not specifically described, the V-shaped wall panels 7 may be collectively referred to herein, or in the drawings, with various suffixes such as a, b, etc. for the purpose of distinguishing or convenience of description, similar descriptions also refer to wall panel sets 6, 6a, etc.

Each V-shaped wall panel 7 may have a front end and a rear end. I.e. the two ends of the V-shaped wall plate 7 are at different positions in front and back, respectively.

In each of the wall plate groups 6, two outermost V-shaped wall plates 7b located outermost in the thickness direction D1 provide a part of the two side surfaces S1, S2 of the metal core 11, respectively. That is, the outermost V-shaped wall plates 7b on the same side of the aforementioned at least one wall plate group 6 may together constitute one side panel 4. In fig. 7, the outermost V-shaped wall plate 7 may be provided with a plurality of perforations 71.

The mutually butted V-shaped wall plates 7 can jointly play an energy absorption role. Stress concentration at the interface can be avoided by using V-shaped wall plates 7.

As previously described, the lattice structure 3 may include the rear rib 51, the rear rib 51 providing the rear end face S3 of the metal core 11. In fig. 6, the rear end 71 of each V-shaped wall plate 7 of the rearmost wall plate group 6a located rearmost of the aforementioned at least one wall plate group 6 is connected to the rear rib 51.

In fig. 6, the lattice structure 3 may further comprise inner ribs 53. The aforementioned at least one wall panel set 6 comprises two adjacent wall panel sets, e.g. 6a, 6c. The two wall plate groups 6a, 6c are a front wall plate group 6c and a rear wall plate group 6a located on the front side and the rear side, respectively. The rear end 71 of each V-shaped wall plate 7 in the front wall plate group 6c is connected to the front side portion of the inner rib 53. The front end 72 of each V-shaped wall plate 7 in the rear wall plate group 6a is connected to the rear side portion of the inner rib 53. The inner rib 53 and the rear rib 51 may together be used to maintain the integrity of the lattice structure 3.

In fig. 6, the lattice structure 3 may further comprise a front rib 52. The front end 72 of each V-shaped wall plate 7 of the foremost wall plate group 6b of the aforementioned at least one wall plate group 6 is connected to the front rib 52.

The metal core 11 may comprise a body portion 110, and the lattice structure 3 is connected to the body portion 110 by the front rib 52, for example, by welding. The body portion 110, i.e. the portion of the metal core 11 other than the tail portion 111 constituted by the lattice structure 3.

With continued reference to fig. 6, the aforementioned plurality of X-shaped wall panels 61 of each wall panel set 6 are divided into a plurality of wall panel pairs, such as three in fig. 6. Each wall plate pair is made up of two adjacent X-shaped wall plates 61, e.g. 61m, 61 n. Of the two X-shaped wall plates 61m, 61n belonging to the same wall plate pair, the rear side branches 713m, 713n of the V-shaped wall plates 71m, 71n which are adjacent (in the thickness direction D1) respectively belonging to the two X-shaped wall plates 61m, 61n intersect each other, while the front side branches 714m, 714n come together at the front side.

In other words, the left (rear) portion in fig. 6 of the two X-shaped wall plates 61m, 61n belonging to the same wall plate pair is partially overlapped or crossed in the thickness direction D1, while the right (front) portion is immediately adjacent in the thickness direction D1.

In one embodiment, the lattice structure 3 of the blade metal structure 1 may be integrally formed by additive manufacturing. Additive manufacturing (3D printing) is a rapid prototyping technique that can directly manufacture three-dimensional objects of nearly arbitrary shape by constructing objects in a layer-by-layer stacked and accumulated manner using powdery bondable materials, such as metal powder, plastic powder, etc. The additive manufacturing technology is applied to the fan blade of the aeroengine, and based on the characteristics of flexible and various processable structures, particularly internal structure forms, the impact resistance of the blade can be effectively improved through the design of a local structure on the premise of reducing the weight of the blade to the maximum extent.

It will be appreciated from the disclosure herein that the division of the lattice structure 3 into individual rib, panel, etc. structures is provided herein and in particular the foregoing for convenience in describing the construction of the lattice structure 3 and is not intended to limit the rib, panel, etc. to individual, separate members.

For example, in practice, the main body of the blade metal structure 1 (including the main body portion 110 of the metal core 11 and the metal leading edge 12) may be machined by subtractive machining, while the tail lattice structure 3 may be printed directly onto the machined main body using an additive manufacturing process. Therefore, the flexible advantage of design can be fully developed, and the development needs of small-batch and rapid iteration are met.

It is to be understood that the use of specific words to describe embodiments of the invention, such as "one embodiment," "another embodiment," and/or "some embodiments" means that a particular feature, structure, or characteristic is associated with at least one embodiment of the invention. Thus, it should be emphasized and should be appreciated that two or more references to "one embodiment" or "another embodiment" in this specification at different positions are not necessarily referring to the same embodiment. Furthermore, certain features, structures, or characteristics of one or more embodiments of the invention may be combined as suitable.

In the blade metal structure 1, the grid structure 3 comprises rib plates and wall plates which penetrate through each other, and can be used as an impact rigidity coordination structure of the metal sandwich type fan blade 10. Wherein the outermost V-shaped wall plate 7 and the rear rib 51 are connected to the composite matrix 2 by distributed perforations such as 71, respectively. The inner rib 53 and the rear rib 51 together serve to maintain the integrity of the lattice structure 3. The V-shaped panels 7, which cross each other, together act as energy absorber.

The rigidity of the grid structure 3 is reduced compared with that of the original solid structure, and the rebound speed is low. During actual design and manufacture, proper wallboard thickness and cross angle can be designed according to the blade profile parameters of the fan blade and the characteristics of the composite material fiber weaving structure, or the wallboard thickness and the cross angle between the wallboard thickness are changed, so that the rigidity of the grid structure 3 is coordinated with the composite material matrix at the rear end P1 of the blade, the deformation consistency is improved, and the composite material matrix at the rear end P1 of the blade is prevented from being torn due to the fact that the deformation of the two components is inconsistent under the impact and rebound effects. On the other hand, the rear rib plate 51 and the inner rib plate 53 can maintain the integrity and certain rigidity of the elastic structure in the impact deformation process, and the prefabricated body fiber of the composite material matrix 2 can be respectively wound and connected with the lower wall plate 4b, the upper wall plate 4a and the rear rib plate 51 of the grid structure 3 through the perforations such as 71, and the grid structure 3 can limit the deformation of the composite material matrix at the rear end P1 of the blade in the bird strike process by virtue of good toughness of the metal material, so that the composite material matrix is prevented from being directly torn due to overlarge deformation.

Referring to fig. 3, 4 and 7, the metal sandwich fan blade 10 provided by the present invention includes the blade metal structure 1 and the composite substrate 2. The composite matrix 2 may be connected to the lattice structure 3 of the leaf metal structure 1 by stitching. For the illustrated embodiment, the stitches may pass through the outermost V-shaped wall panel 7 and the perforations 71 of the back rib 51 to join the lattice structure 3 of the blade metal structure 1 with the composite matrix 2. The suture may be a fiber, or a fiber contained in the composite matrix 2 itself may be used, or a fiber may be provided. For example, the preformed fibers of the composite matrix 2 are entangled with the lattice structure 3 through these perforations, such as 71, with high strength of attachment and good overall performance.

In the metal sandwich fan blade, the hollow elastic structure formed by the grid structure is formed by combining the rib plates and the wall plates which are mutually connected in a cross manner, the rib plates are used for maintaining the structural integrity, and the mutually crossed wall plates form the elastic structure. The wall plate at the outermost side of the grid structure is provided with small holes which can be connected with the composite material prefabricated body. Moreover, according to the thickness of the blade profile of the fan blade and the weaving structure of the composite material fibers, grid structures with different wall plate thicknesses and cross angles can be designed to be coordinated with the rigidity of the composite material, in particular, the impact resistance rigidity is coordinated with the composite material matrix, the situation that the composite material matrix at the rear end of the blade is torn due to inconsistent deformation of the two materials in the bird strike process of the blade is avoided, and the impact resistance of the blade is enhanced.

The metal sandwich type fan blade can effectively prevent the composite material at the tail of the blade from being torn caused by bird strike, and has the advantage of light weight.

While the invention has been described in terms of preferred embodiments, it is not intended to be limiting, but rather to the invention, as will occur to those skilled in the art, without departing from the spirit and scope of the invention. Therefore, any modification, equivalent variation and modification of the above embodiments according to the technical substance of the present invention fall within the protection scope defined by the claims of the present invention.

Claims (10)

1. A blade metal structure for a metal sandwich type fan blade, the blade metal structure comprising a metal core for being clamped by a composite substrate of the metal sandwich type fan blade, the blade metal structure having a thickness direction and a spanwise direction, characterized in that,

the metal core has a mesh structure having a plurality of meshes extending in a spanwise direction and discretely distributed at a tail portion, the mesh structure providing rear side portions of both side surfaces of the metal core in a thickness direction and a rear end face of the metal core.

2. The blade metal structure of claim 1, wherein the lattice structure includes two side panels separately provided in a thickness direction, providing rear side portions of both side surfaces of the metal core, respectively;

each side panel is provided with a plurality of perforations.

3. The blade metal structure of claim 1, wherein the lattice structure further comprises a rear rib providing a rear face of the metal core;

the rear rib is provided with a plurality of perforations.

4. The blade metal structure of claim 1, wherein the lattice structure comprises:

at least one wall plate group, which is sequentially distributed from front to back, each wall plate group comprises a plurality of X-shaped wall plates distributed along the thickness direction, each X-shaped wall plate comprises two V-shaped wall plates which are butted to form an X shape, and each V-shaped wall plate is provided with a front end and a rear end;

in each panel group, two outermost V-shaped panels located outermost in the thickness direction provide a portion of both side surfaces of the metal core, respectively.

5. The blade metal structure of claim 4, wherein the lattice structure further comprises a rear rib providing a rear face of the metal core;

the rear end of each V-shaped wall plate of the rearmost wall plate group located rearmost of the at least one wall plate group is connected to the rear rib.

6. The blade metal structure of claim 4, wherein the lattice structure further comprises an inner rib, the at least one panel group comprises two adjacent panel groups, a front panel group and a rear panel group on front and rear sides, respectively, a rear end of each V-shaped panel in the front panel group being connected to a front side portion of the inner rib, and a front end of each V-shaped panel in the rear panel group being connected to a rear side portion of the inner rib.

7. The blade metal structure of claim 4, wherein the lattice structure further comprises a front rib to which a front end of each V-shaped panel of the at least one panel group located at a foremost side is connected;

the metal core includes a body portion, and the lattice structure is connected to the body portion by the front rib.

8. The blade metal structure of claim 4 wherein the outermost V-shaped web is provided with a plurality of perforations.

9. The blade metal structure of claim 4, wherein the lattice structure of the blade metal structure is integrally formed by additive manufacturing.

10. A metal sandwich fan blade, comprising:

the blade metal structure of any one of claims 1 to 9; and

the composite material matrix is connected with the grid structure of the blade metal structure through suture.