Preparation method of bionic beetle skeleton implant

Abstract

The invention discloses a preparation method of a bionic beetle skeleton implant, and belongs to the field of femoral implantation. The bionic structure characteristics of beetle elytra and cuticle are creatively combined, the mechanical strength and structural stability of the porous nickel-titanium alloy structure implant are effectively improved through the bionic structure design method, and the long-standing stress shielding effect problem of a traditional femoral metal implant is successfully solved; the porous nickel-titanium alloy bionic skeleton structure prepared by adopting a selective laser melting (SLM) technology not only has good mechanical suitability, avoids rejection and shedding reaction with natural bone tissues after implantation, but also can realize a complete shape memory recovery function in a room temperature environment, and has good application prospects in the field of medical orthopedic implantation.

Description

Technical Field

[0001] The invention belongs to the field of femoral implantation, and in particular relates to a method for preparing a bionic beetle skeleton implant. Background Art

[0002] Nickel-titanium alloy, a type of titanium alloy, is considered a promising material for bone implants due to its low elastic modulus and excellent large deformation recovery compared to other titanium alloys (such as TC4). Its inherent superelasticity and shape memory properties contribute to post-implant stability. However, compared to natural bone tissue, the elastic modulus of solid nickel-titanium is too high, resulting in a large stiffness mismatch between the metal implant and the adjacent host bone, which can lead to stress shielding and cause implant dislocation and fallout.

[0003] Porous titanium alloys have been proven to have significantly lower elastic modulus than solid materials, effectively reducing stress shielding. To date, there are many methods for preparing porous titanium alloys. As early as the 1960s, researchers have prepared porous titanium alloys through powder sintering, foaming, gel casting and other methods, and applied them to the field of bone repair. However, in recent years, researchers have found that metal porous scaffolds prepared by traditional processing methods have limitations in customizing key structural properties (such as porosity, pore size) and corresponding mechanical properties. Additive manufacturing (AM) technology can not only achieve adjustable porosity according to the needs of skeleton implantation, but also realize personalized design for different implant sites. It can be widely used in clinical implantation as a customizable processing method.

[0004] Additively manufactured porous structures are typically designed using methods such as computer-aided design, implicit surface modeling, image-based design, and topology optimization. However, traditional structures such as BCC (body-centered cubic) and FCC (face-centered cubic) fabricated using these methods often suffer from insufficient strength and premature structural instability, making it difficult to achieve a balance between strength and stiffness.

[0005] Therefore, the field of bone implant design needs to explore new structural designs and new manufacturing methods that are adapted to corresponding materials to meet clinical needs. Summary of the Invention

[0006] In view of the above problems existing in the prior art, the object of the present invention is to provide a method for preparing a bionic beetle skeleton implant.

[0007] In order to solve the above problems, the technical solutions adopted by the present invention are as follows: A method for preparing a bionic beetle skeleton implant comprises the following steps: Step 1: Building a bionic beetle skeleton based on 3D modeling software. The bionic beetle skeleton includes a bionic shell structure and a bionic rib structure. The bionic shell structure and the bionic rib structure are spliced ​​together to form a bionic skeleton. The bionic skeletons are coupled and spliced ​​together to form a multi-layered bionic beetle skeleton. Step 2: Import the bionic beetle skeleton designed in step 1 into Magics software, and shape the metal material into a bionic beetle skeleton based on the selective laser melting technology; Step three: polish the bionic beetle skeleton manufactured in step two and then clean it.

[0008] Furthermore, the bionic shell structure in step one includes a bionic triangular shell structure, a bionic quadrangular shell structure and a bionic hexagonal shell structure, and the bionic rib structure includes a bionic triangular rib structure, a bionic quadrangular rib structure and a bionic hexagonal rib structure.

[0009] Furthermore, the specific splicing method of the bionic skeleton is as follows: The bionic shell structures are connected to each other through bionic rib structures with corresponding numbers of edges.

[0010] Furthermore, the method for establishing the bionic triangular shell structure in step 1 is as follows: Design based on a hollow regular triangular prism, determine the three vertices of the top of the regular triangular prism as A, B, and C, determine the three vertices of the bottom of the regular triangular prism as D, E, and F, point D is directly below point A, point E is directly below point B, and point F is directly below point C. The center points of the three sides of the regular triangular prism are H, I, and J, respectively, where point H is the center point of plane ABED, I is the center point of plane ACDF, and point J is the center point of plane BCEF. Also, determine that the direction of line segment EF is the X-axis and the direction of line segment CF is the Z-axis; The surface is established based on each calibration point. The surface consists of four segments. The first segment is: Construct arc AB with vertices A and B as starting points and planes ABED and ABC as reference planes. The distance between the midpoint of arc AB and plane ABED is n, and n is less than the shortest distance between line AB and the center point of plane ABC. The distance between the midpoint of arc AB and plane ABC is m, and m is less than the shortest distance between line AB and the center point of plane ABED. The second and third segments are: Construct symmetrical points V and U on both sides of the face center H. The distance between point V and point U and point H is c. Point V is close to the side of line AD, and point U is close to the side of line BE. With vertices A and B as starting points, construct arcs AV and BU on plane ABED. Arcs AV and BU are the second and third segments respectively. The fourth segment is: The straight line VU is the fourth segment; Merge the four line segments to obtain the curve ABUV, then fill the curve ABUV with a surface to obtain the surface ABUV, and thicken and round the constructed surface; Repeat the above steps to create the same surface based on the remaining two sides of the regular triangular prism. Then, mirror the created surface with the plane HIJ formed by the center points of the surface as the reference to form a triangular shell structure monomer. The triangular shell structure monomers are arrayed once along the X-axis and the Z-axis respectively, and finally the arrayed structure is solid mirrored along the reference plane BCEF to form a bionic triangular shell structure.

[0011] Furthermore, the method for establishing the bionic tetrahedral shell structure in step 1 is as follows: Design based on a hollow regular square prism. Determine a vertex at the top of the regular square prism as K, a vertex at the bottom of the regular square prism as L, and point K is located directly above point L. Determine the center of the regular square prism as M. With point L as the center point, select the three edges connected to a vertex at the bottom of the regular square prism as the X-axis, Y-axis, and Z-axis; Using the contour line of plane KLM as the path, a circular scan operation is performed on the path to create a triangular structure with a circular cross-section. The corners of the cylindrical structure are then rounded at points K and L. Establish a symmetry axis perpendicular to the base of the regular quadrangular prism and passing through the center point M. Arrange the rounded triangular structure in a circular pattern four times around the symmetry axis to form a quadrangular shell structure. The tetrahedral shell structure monomers are arrayed in sequence along the X-axis, Y-axis and Z-axis directions to form a bionic tetrahedral shell structure.

[0012] Furthermore, the method for establishing the bionic hexagonal shell structure in step 1 is as follows: Design based on a hollow regular hexagonal prism. Determine the top vertices of one side of the regular hexagonal prism as N and O, and the bottom vertices of one side of the regular hexagonal prism as P and Q. Point N is located directly above point P, and point O is located directly above point Q. Determine the center point of plane NOPQ as R, and the center point of the regular hexagonal prism as S. The perpendicular line passing through point S and perpendicular to the base of the regular hexagonal prism is the Z axis, the perpendicular line between point S and the side of the regular hexagonal prism is the X axis, and an axis perpendicular to the Z and X axes is the Y axis. Delete the edges NP and OQ perpendicular to the base. Create curved beams with points N, O, P, and Q pointing toward the center R. Create a symmetry axis perpendicular to the base of the regular hexagonal prism and passing through the center S of the regular hexagonal prism. Arrange the curved beams on plane NPOQ six times in a circular pattern around the symmetry axis. Delete the other vertical edges of the regular hexagonal prism. Replace all six sides of the regular hexagonal prism with curved beams. Based on all the vertices at the top and bottom of the hollow hexagonal prism, arc beams are made with all vertices facing the body center point S to form a hexagonal shell structure monomer; The hexagonal shell structure monomers are arrayed in sequence along the X-axis, Y-axis and Z-axis directions to form a bionic hexagonal shell structure.

[0013] Furthermore, the method for establishing the bionic triangular rib structure in step 1 is as follows: The design is based on a hollow regular triangular prism. The center point of the regular triangular prism is determined to be T. An arc beam is made with each vertex of the regular triangular prism pointing to point T. The arc beam is the rib structure. Then, other structures except the rib structure are deleted from the regular triangular prism to obtain a triangular rib structure monomer. The triangular rib structure monomers are arrayed once along the X-axis direction, and the arrayed structure is mirrored once with the reference plane as the reference entity to form a bionic triangular rib structure.

[0014] Furthermore, the method for establishing the bionic quadrangular rib structure in step 1 is as follows: Based on the hollow regular quadrangular prism, the design is carried out, and arc beams are made with each vertex of the regular quadrangular prism facing the center point M. The arc beams are the rib structures. Then, other structures except the rib structures are deleted from the regular quadrangular prism to obtain a quadrangular rib structure monomer; The four-sided rib structure monomers are arrayed in sequence along the X-axis and the Y-axis directions to form a bionic four-sided rib structure.

[0015] Furthermore, the method for establishing the bionic hexagonal rib structure in step 1 is as follows: Based on the design of a hollow regular hexagonal prism, a curved beam is made with each vertex of the regular hexagonal prism facing the center point S. The curved beam is the rib structure. Then, other structures except the rib structure are deleted from the regular hexagonal prism to obtain a hexagonal rib structure monomer. The hexagonal rib structure monomers are arrayed in sequence along the X-axis and the Y-axis directions to form a bionic hexagonal rib structure.

[0016] Furthermore, the selective laser melting technology in step 2 uses a laser power of 200 W, a scanning speed of 1000 mm / s, a scanning layer thickness of 40 μm, and a scanning spacing of 80 μm as a printing strategy.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The present invention applies the bionic beetle structure to the field of medical femoral implants, combining the bionic structures of the beetle's elytra and cuticle to make up for the lack of strength and structural stability, and solve the "stress shielding" problem that has long been criticized in clinical medicine, so that the implant does not undergo a rejection reaction with natural bone after implantation. After the preparation of traditional additive manufacturing porous skeletons, more or less powder particles will adhere to the surface of the sample. It is difficult to completely remove the powder particles through ultrasonic treatment alone. The present invention chemically polishes the prepared bionic nickel-titanium skeleton, effectively removing the metal powder particles adhering to the surface of the skeleton, avoiding inflammation caused by powder shedding due to impact vibration after implantation.

[0018] In the prior art, it is difficult for the nickel-titanium porous skeleton manufactured by additive manufacturing to fully realize the shape memory recovery function at room temperature, while the porous nickel-titanium skeleton structure of the present invention can realize complete shape memory recovery at room temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the microscopic representation of the elytra (left) and exoskeleton cuticle (right) of the rainbow mites beetle in nature; Figure 2 This is a schematic diagram of the design of the bionic beetle skeleton structure; Figure 3 This is a schematic diagram of the bionic triangular shell structure designed by the present invention; Figure 4 This is a schematic diagram of the bionic quadrangular shell structure designed by the present invention; Figure 5 Schematic diagram of the bionic hexagonal shell structure designed by the present invention; Figure 6 Schematic diagram of three types of rib structure monomers designed by the present invention, which are respectively adapted to three types of shell structure monomers; Figure 7 Schematic diagrams of three types of bionic rib structures of the present invention; Figure 8 Schematic diagram of the multi-level bionic beetle skeleton coupling of the present invention; Figure 9 It is a schematic diagram of the shape recovery effect of the multi-level bionic beetle skeleton of the present invention at room temperature and a schematic diagram of the phase change temperature curve.

[0020] In the figure: 1. Bionic triangular skeleton; 11. Bionic triangular shell structure; 12. Bionic triangular rib structure; 111. Triangular shell structure monomer; 121. Triangular rib structure monomer; 2. Bionic quadrangular skeleton; 21. Bionic quadrangular shell structure; 22. Bionic quadrangular rib structure; 211. Quadrangular shell structure monomer; 221. Quadrangular rib structure monomer; 3. Bionic hexagonal skeleton; 31. Bionic hexagonal shell structure; 32. Bionic hexagonal rib structure; 311. Hexagonal shell structure monomer; 321. Hexagonal rib structure monomer; 4. Bionic beetle skeleton. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to specific embodiments.

[0022] The present invention discloses a method for preparing a bionic beetle skeleton implant, which comprises the following steps: Step 1: Use Solidworks 3D modeling software to complete parametric design. The three designed biomimetic shell structures and the corresponding three biomimetic rib structures are assembled into a biomimetic triangular skeleton 1, a biomimetic quadrangular skeleton 2, and a biomimetic hexagonal skeleton 3. The biomimetic rib structure is placed between the two biomimetic shell structures to stabilize deformation under load, while the biomimetic shell structure primarily absorbs and dissipates energy under load. The biomimetic triangular skeleton 1, the biomimetic quadrangular skeleton 2, and the biomimetic hexagonal skeleton 3 are coupled together to form a multilevel biomimetic beetle skeleton 4 (MBBS), which further achieves synergistic vibration reduction.

[0023] Step 2: Convert the structure of the bionic beetle skeleton 4 designed in step 1 into an Stl format file and import it into Magics software. Based on the selective laser melting technology (SLM), the metal material is formed into a multi-layered bionic beetle skeleton 4.

[0024] Step 3: The bionic beetle skeleton 4 is polished by a chemical method, and then ultrasonically treated while soaking in alcohol to remove powder adhering to the surface.

[0025] The bionic beetle skeleton 4 of this solution is derived from the carapace structure of the stag beetle, see Figure 1 As shown, electron microscopy of the elytra and exoskeleton of the rainbow shovel revealed elliptical and circular hollow cavities composed of fibers in the elytra. This characteristic structure has been shown to be a key factor in the beetle's excellent energy absorption properties. Bouligand structures with rotational angles were observed in the cuticle of the beetle's exoskeleton, which has also been shown to contribute to the beetle's stable deformation.

[0026] See Figure 2 As shown, the bionic shell structure in the step 1 includes a bionic triangular shell structure 11 (Bionic triangular shell structure, BTSS), a bionic quadrilateral shell structure 21 (Bionic quadrilateral shell structure, BQSS) and a bionic hexagonal shell structure 31 (Bionic hexagonal shell structure, BHSS), and the bionic rib structure includes a bionic trilateral rib structure 12 (Bionic trilateral rib structure, BTRS), a bionic quadrilateral rib structure 22 (Bionic quadrilateral rib structure, BQRS) and a bionic hexagonal rib structure 32 (Bionic hexagonal rib structure, BHRS).

[0027] The monomers of the bionic shell structure in step one include a triangular shell structure monomer 111, a quadrangular shell structure monomer 211 and a hexagonal shell structure monomer 311. The design of the structural monomers of each shell is inspired by the hollow chamber structure of the beetle elytra, and are divided into three categories according to the different chambers formed; and the monomers of the bionic rib structure include a triangular rib structure monomer 121, a quadrangular rib structure monomer 221 and a hexagonal rib structure monomer 321. Their design is based on the spiral torsion characteristics of the Bouligand structure of the beetle exoskeleton cuticle, and corresponds to their respective shell structures.

[0028] After arraying, mirroring and combining operations, each structural monomer will form a bionic triangular shell structure 11, a bionic quadrangular shell structure 21, a bionic hexagonal shell structure 31, a bionic triangular rib structure 12, a bionic quadrangular rib structure 22 and a bionic hexagonal rib structure 32 respectively.

[0029] The bionic triangular skeleton 1 in step 1 is composed of two bionic triangular shell structures 11 and a bionic triangular rib structure 12; the bionic quadrangular skeleton 2 is composed of two bionic quadrangular shell structures 21 and a bionic quadrangular rib structure 22; the bionic hexagonal skeleton 3 is composed of two bionic hexagonal shell structures 31 and a bionic hexagonal rib structure 32.

[0030] The three types of bionic beetle skeleton structures have a common feature, that is, their corresponding bionic shell structures are placed on both sides as the top unit and the bottom unit respectively, and the corresponding bionic rib structures are located in the middle area of ​​the top unit and the bottom unit for connection. When bearing loads, the bionic shell structure mainly plays the role of bearing energy absorption and dissipating the energy borne, while the bionic rib structure mainly plays the role of stabilizing deformation and smooth transition.

[0031] See Figure 3 As shown, the design of the bionic triangular shell structure 11 is as follows: First, an optimization design is performed based on a hollow regular triangular prism. The three vertices of the top of the regular triangular prism are determined to be A, B, and C. The three vertices of the bottom of the regular triangular prism are determined to be D, E, and F. Point D is directly below point A, point E is directly below point B, and point F is directly below point C. The center points of the three sides of the regular triangular prism are H, I, and J, respectively. Point H is the center point of plane ABED, I is the center point of plane ACDF, and J is the center point of plane BCEF. The center point of the regular triangular prism is point T. The direction of line segment EF is determined to be the X-axis, and the direction of line segment CF is determined to be the Z-axis. First, the curve is drawn based on the 3D sketch operation. The curve consists of four line segments. The first part is an arc, which is extended by the curvature of vertices A and B. Arc AB is constructed with plane ABED and plane ABC as reference planes. The distance between the midpoint of arc AB and plane ABED is n, and n is less than the shortest distance between the straight line AB and the center point of plane ABC. The distance between the midpoint of arc AB and plane ABC is m, and m is less than the shortest distance between the straight line AB and the center point of plane ABED. The second and third parts are still arcs. 3D arcs are drawn based on vertices A and B respectively, extending from vertices A and B to V and U of plane ABED. Point V and point U are located at the left and right ends of point H, respectively, and the distance between them and point H is set to c. The fourth line segment is line UV, which is also implemented by the 3D sketch command. Secondly, the 3D curve ABUV drawn above is filled with a surface, and the constructed surface is thickened and partially rounded. Repeat the above steps to establish the same surface based on the remaining two side surfaces of the regular triangular prism. After the establishment, the solid surfaces BCWX, ACYZ and ABUV are obtained. Then the three surfaces are closed to each other. Finally, the established surface is mirrored with the plane HIJ formed by the center points as the reference. At this time, the combined entity forms a triangular shell structure monomer 111 with a length × width × height = a1 × b1 × c1.

[0032] The extended positions of vertices B and C in the constructed surface BCWX are located at points X and W of plane BCEF (points X and W are located at the left and right ends of point J, and the distance between them is set to c). The extended positions of vertex AC in the constructed surface ACYZ are located at points Z and Y of plane ACFD (points Y and Z are located at the left and right ends of I, and the distance between them is set to c). The triangular shell structure monomer 111 is arrayed once along the X-axis and the Z-axis respectively, and finally the arrayed structure is arrayed along the reference plane BCEF (i.e. Figure 3The reference plane 1) in the figure is subjected to a solid mirroring operation to form a bionic triangular shell structure 11 with a size of 2a1×2b1×2c1.

[0033] See Figure 4 As shown, the design scheme of the bionic quadrangular shell structure 21 is as follows: based on the optimization design of a hollow regular quadrangular prism, a vertex at the top of the regular quadrangular prism is determined as K, a vertex at the bottom of the regular quadrangular prism is determined as L, point K is located directly above point L, the center of the regular quadrangular prism is determined as M, and with point L as the center point, three edges connected to a vertex at the bottom of the regular quadrangular prism are selected as the X axis, the Y axis, and the Z axis; A 3D sketch is drawn toward the center M of the quadrangular prism, using the KL vertex as the basis. This path can be understood as the outline of the plane KLM. A circular sweep is then used to sweep the path, followed by rounding the cylindrical structure at points K and L. Rounding serves to smoothly disperse stress. Compared to sharp corners and node structures, rounded corners can effectively reduce stress concentration and further improve the structure's fatigue resistance. A symmetry axis 3 is established perpendicular to the base of the regular quadrangular prism and passing through the center M. Finally, a circular array is formed using the symmetry axis 3 as the reference, with a number of arrays of 4, forming a quadrangular shell structure monomer 211 with dimensions a2×b2×c2.

[0034] Then, the quadrangular shell structure monomer 211 with a size of a2×b2×c2 is arrayed once along the X-axis, Y-axis and Z-axis directions respectively, forming a bionic quadrangular shell structure 21 with a size of 2a2×2b2×2c2.

[0035] See Figure 5 As shown, the design scheme of the bionic hexagonal shell structure 31 is as follows: based on the optimization design of a hollow regular hexagonal prism, the bottom vertices of one side of the regular hexagonal prism are determined to be P and Q respectively, point N is located directly above point P, and point O is located directly above point Q. The center point of the plane NOPQ is determined to be R, and the center point of the regular hexagonal prism is determined to be S. The vertical line passing through point S and perpendicular to the bottom surface of the regular hexagonal prism is used as the Z axis, the vertical line between point S and the side surface of the regular hexagonal prism is used as the X axis, and an axis perpendicular to the Z axis and the X axis is used as the Y axis. First, the original pillars NP and OQ are deleted, and four arc beams are established with N, P, O, and Q as endpoints. All arc beams intersect at the face center position R. A symmetry axis 4 is established that is perpendicular to the base of the regular hexagonal prism and passes through the body center point S of the regular hexagonal prism. Then, the solid arc beam structure formed at plane NOPQ is circularly arrayed around the symmetry axis 4. The number of circular arrays is 6. The other vertical edges of the regular hexagonal prism are deleted, and the entities after the array are ensured to be closed to each other, and the overall size is the same as that of the regular hexagonal prism.

[0036] A sketch is then drawn for path scanning. The path starts at the six vertices of the upper plane of the regular hexagonal prism and ends at the center S of the regular hexagonal prism. The path is an arc, with the center close to the side of the regular hexagonal prism. The scanned contour is a circular contour with a radius of r. The resulting solid unit is then mirrored along the symmetry axis 5, which passes through the center S and is parallel to the top surface of the hexagonal prism. This mirrored unit intersects the six vertices of the lower plane of the regular hexagonal prism. Alternatively, a path can be directly created using the twelve vertices of the upper and lower planes of the regular hexagonal prism, and a circular contour scan is performed to form a hexagonal shell structure unit 311 with dimensions a3×b3×c3.

[0037] Finally, the hexagonal shell structure monomers 311 with the size of a3×b3×c3 are arrayed once along the X axis, Y axis and Z axis respectively, and after combining the entities, a bionic hexagonal shell structure 31 with the size of 2a2×2b2×2c2 is obtained.

[0038] See Figure 6 As shown, the design schemes of the triangular rib structure monomer 121, the quadrangular rib structure monomer 221 and the hexagonal rib structure monomer 321 are as follows: Similarly, using the hollow regular triangular prism, regular quadrangular prism, and regular hexagonal prism as references, a path scan with a circular contour radius of r2 is first performed. The path starts at the vertices of the upper planes of the regular triangular prism, regular quadrangular prism, and regular hexagonal prism, and ends at the respective body centers T, M, and S. The path is an arc, with the arc centers close to the top and bottom surfaces of the regular polygonal prism. Finally, entities other than the ribs are removed. After scaling and combining the entities, a triangular rib structure monomer 121 with dimensions of a1×b1×c1, a quadrangular rib structure monomer 221 with dimensions of a2×b2×c2, and a hexagonal rib structure monomer 321 with dimensions of a3×b3×c3 are obtained. These monomer dimensions are designed to adapt to the corresponding bionic shell structures.

[0039] See Figure 7 It can be seen that the bionic rib structure is obtained by arraying and mirroring the rib structure monomers. The triangular rib structure monomer 121 (with dimensions of a1×b1×c1) is arrayed along the X axis, with the number of arrays being 1. Then, the entities are combined and mirrored once using the reference plane 2 (i.e., the plane BCEF corresponding to the construction of the triangular shell structure monomer 111) as the reference. After mirroring, the bionic triangular rib structure 12 with dimensions of 2a1×2b1×c1 is obtained. The four-sided rib structure monomer 221 (with a2×b2×c2 dimensions) is arrayed along the X-axis and the Y-axis, with the arraying times being 1, and then the entity is combined to obtain a bionic four-sided rib structure 22 with a size of 2a2×2b2×c2; The hexagonal rib structure monomers 321 (with dimensions of a3×b3×c3) are arrayed along the X-axis and the Y-axis, with the arraying times being 1, and then the entities are combined to obtain the bionic hexagonal rib structure 32 with dimensions of 2a3×2b3×c3.

[0040] It should be noted that when the quadrangular rib structure monomer 221 and the hexagonal rib structure monomer 321 are connected to the quadrangular shell structure monomer 211 and the hexagonal shell structure monomer 311 , the end of each rib of the rib structure monomer is connected to the vertex of the shell structure monomer.

[0041] The beetle exoskeleton presents a multi-layer structure composed of chitin fibers and proteins (such as the outer epidermis and the inner epidermis). The bonding between each layer is enhanced by nano-scale interlocking structures to prevent delamination. Similarly, similar tissue interlocking phenomena also exist in the beetle's elytra. For example, the beetle's hardened forewings and the thorax are interlocked through serrated or hooked structures to achieve a tight closure. It can be seen that multiple parts of beetles in nature can produce a strengthening effect by mechanical interlocking. Therefore, the present invention also draws on the interlocking characteristics of beetles to further strengthen the structure and designs a multi-level bionic beetle skeleton 4, which is composed of a bionic triangular skeleton 1, a bionic quadrangular skeleton 2 and a bionic hexagonal skeleton 3. The bionic quadrangular skeleton 2 is between the bionic triangular skeleton 1 and the bionic hexagonal skeleton 3, and acts as a transition layer when the bionic beetle skeleton 4 faces lateral loads. The specific design effect is as follows. Figure 8 shown.

[0042] In step 2, the biomimetic skeleton was prepared using SLM technology. The material used was nickel-titanium alloy powder (55.8 wt% Ni), which was produced by a gas atomization method and had a powder particle size of 15-53 μm. Laser melting printing was performed under the conditions of a laser power of 200 W, a laser scanning speed of 1000 mm / s, a layer thickness of 40 μm, and a scanning interval of 80 μm.

[0043] The chemical polishing solution used in step 3 is composed of hydrofluoric acid (22.5 mol / L), nitric acid (4 mol / L), and deionized water in a volume ratio of 1:4:5. The purpose of chemical polishing is to remove unmelted particles to prevent inflammation caused by vibration after implantation.

[0044] The working principle of the present invention can be found in Figure 9 As shown, the skeleton implant prepared by the present invention is mainly used for implantation into the femur. When the implant is subjected to load, the implant implanted in the human body dissipates energy by deformation. The memory temperature A of the implant produced based on the nickel-titanium structure is f The measured temperature is 35℃, which is consistent with the normal human body temperature, so the temperature rises to the memory temperature A. fAt this point, the martensite phase in the nickel-titanium shape memory alloy completely transforms into the austenite phase, allowing the biomimetic structure to recover its deformation. The structure designed based on this solution has excellent mechanical properties, and the body's normal temperature deformation recovery properties of nickel-titanium alloy make this solution a promising application in the field of medical stents for bone implants.

Claims

1. A method for preparing a bionic beetle skeleton implant, characterized in that: The steps include: Step 1: Building a bionic beetle skeleton based on 3D modeling software. The bionic beetle skeleton includes a bionic shell structure and a bionic rib structure. The bionic shell structure and the bionic rib structure are spliced ​​together to form a bionic skeleton. The bionic skeletons are coupled and spliced ​​together to form a multi-layered bionic beetle skeleton. Step 2: Import the bionic beetle skeleton designed in step 1 into Magics software, and shape the metal material into a bionic beetle skeleton based on the selective laser melting technology; Step three: polish the bionic beetle skeleton manufactured in step two and then clean it.

2. The method for preparing a bionic beetle skeleton implant according to claim 1, characterized in that: The bionic shell structure in step one includes a bionic triangular shell structure, a bionic quadrangular shell structure and a bionic hexagonal shell structure, and the bionic rib structure includes a bionic triangular rib structure, a bionic quadrangular rib structure and a bionic hexagonal rib structure.

3. The method for preparing a bionic beetle skeleton implant according to claim 2, characterized in that: The specific splicing method of the bionic skeleton is as follows: The bionic shell structures are connected to each other through bionic rib structures with corresponding numbers of edges.

4. The method for preparing a bionic beetle skeleton implant according to claim 2, characterized in that: The method for establishing the bionic triangular shell structure in step 1 is as follows: Design based on a hollow regular triangular prism, determine the three vertices of the top of the regular triangular prism as A, B, and C, determine the three vertices of the bottom of the regular triangular prism as D, E, and F, point D is directly below point A, point E is directly below point B, and point F is directly below point C. The center points of the three sides of the regular triangular prism are H, I, and J, respectively, where point H is the center point of plane ABED, I is the center point of plane ACDF, and point J is the center point of plane BCEF. Also, determine that the direction of line segment EF is the X-axis and the direction of line segment CF is the Z-axis; The surface is established based on each calibration point. The surface consists of four segments. The first segment is: Construct arc AB with vertices A and B as starting points and planes ABED and ABC as reference planes. The distance between the midpoint of arc AB and plane ABED is n, and n is less than the shortest distance between line AB and the center point of plane ABC. The distance between the midpoint of arc AB and plane ABC is m, and m is less than the shortest distance between line AB and the center point of plane ABED. The second and third segments are: Construct symmetrical points V and U on both sides of the face center H. The distance between point V and point U and point H is c. Point V is close to the side of line AD, and point U is close to the side of line BE. With vertices A and B as starting points, construct arcs AV and BU on plane ABED. Arcs AV and BU are the second and third segments respectively. The fourth segment is: The straight line VU is the fourth segment; Merge the four line segments to obtain the curve ABUV, then fill the curve ABUV with a surface to obtain the surface ABUV, and thicken and round the constructed surface; Repeat the above steps to create the same surface based on the remaining two sides of the regular triangular prism. Then, mirror the created surface with the plane HIJ formed by the center points of the surface as the reference to form a triangular shell structure monomer. The triangular shell structure monomers are arrayed once along the X-axis and the Z-axis respectively, and finally the arrayed structure is solid mirrored along the reference plane BCEF to form a bionic triangular shell structure.

5. The method for preparing a bionic beetle skeleton implant according to claim 2, characterized in that: The method for establishing the bionic tetrahedral shell structure in step 1 is as follows: Design based on a hollow regular square prism. Determine a vertex at the top of the regular square prism as K, a vertex at the bottom of the regular square prism as L, and point K is located directly above point L. Determine the center of the regular square prism as M. With point L as the center point, select the three edges connected to a vertex at the bottom of the regular square prism as the X-axis, Y-axis, and Z-axis; Using the contour line of plane KLM as the path, a circular scan operation is performed on the path to create a triangular structure with a circular cross-section. The corners of the cylindrical structure are then rounded at points K and L. Establish a symmetry axis perpendicular to the base of the regular quadrangular prism and passing through the center point M. Arrange the rounded triangular structure in a circular pattern four times around the symmetry axis to form a quadrangular shell structure. The tetrahedral shell structure monomers are arrayed in sequence along the X-axis, Y-axis and Z-axis directions to form a bionic tetrahedral shell structure.

6. The method for preparing a bionic beetle skeleton implant according to claim 2, characterized in that: The method for establishing the bionic hexagonal shell structure in step 1 is as follows: Design based on a hollow regular hexagonal prism. Determine the top vertices of one side of the regular hexagonal prism as N and O, and the bottom vertices of one side of the regular hexagonal prism as P and Q. Point N is located directly above point P, and point O is located directly above point Q. Determine the center point of plane NOPQ as R, and the center point of the regular hexagonal prism as S. The perpendicular line passing through point S and perpendicular to the base of the regular hexagonal prism is the Z axis, the perpendicular line between point S and the side of the regular hexagonal prism is the X axis, and an axis perpendicular to the Z and X axes is the Y axis. Delete the edges NP and OQ perpendicular to the base. Create curved beams with points N, O, P, and Q pointing toward the center R. Create a symmetry axis perpendicular to the base of the regular hexagonal prism and passing through the center S of the regular hexagonal prism. Arrange the curved beams on plane NPOQ six times in a circular pattern around the symmetry axis. Delete the other vertical edges of the regular hexagonal prism. Replace all six sides of the regular hexagonal prism with curved beams. Based on all the vertices at the top and bottom of the hollow hexagonal prism, arc beams are made with all vertices facing the body center point S to form a hexagonal shell structure monomer; The hexagonal shell structure monomers are arrayed in sequence along the X-axis, Y-axis and Z-axis directions to form a bionic hexagonal shell structure.

7. The method for preparing a bionic beetle skeleton implant according to claim 4, characterized in that: The method for establishing the bionic triangular rib structure in step 1 is as follows: The design is based on a hollow regular triangular prism. The center point of the regular triangular prism is determined to be T. An arc beam is made with each vertex of the regular triangular prism pointing to point T. The arc beam is the rib structure. Then, other structures except the rib structure are deleted from the regular triangular prism to obtain a triangular rib structure monomer. The triangular rib structure monomers are arrayed once along the X-axis direction, and the arrayed structure is mirrored once with reference plane BCEF as a reference to form a bionic triangular rib structure.

8. The method for preparing a bionic beetle skeleton implant according to claim 5, characterized in that: The method for establishing the bionic quadrangular rib structure in step 1 is as follows: Based on the hollow regular quadrangular prism, the design is carried out, and arc beams are made with each vertex of the regular quadrangular prism facing the center point M. The arc beams are the rib structures. Then, other structures except the rib structures are deleted from the regular quadrangular prism to obtain a quadrangular rib structure monomer; The four-sided rib structure monomers are arrayed in sequence along the X-axis and the Y-axis directions to form a bionic four-sided rib structure.

9. The method for preparing a bionic beetle skeleton implant according to claim 6, characterized in that: The method for establishing the bionic hexagonal rib structure in step 1 is as follows: Based on the design of a hollow regular hexagonal prism, a curved beam is made with each vertex of the regular hexagonal prism facing the center point S. The curved beam is the rib structure. Then, other structures except the rib structure are deleted from the regular hexagonal prism to obtain a hexagonal rib structure monomer. The hexagonal rib structure monomers are arrayed in sequence along the X-axis and the Y-axis directions to form a bionic hexagonal rib structure.

10. The method for preparing a bionic beetle skeleton implant according to claim 1, characterized in that: The selective laser melting technology in step 2 uses a laser power of 200W, a scanning speed of 1000mm / s, a scanning layer thickness of 40μm, and a scanning spacing of 80μm as a printing strategy.

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