A method for constructing a trabecular bone-cement composite finite element model

Abstract

The present application relates to a kind of trabecula-cement composite finite element model construction method, method includes obtaining trabecula microimage data;Reconstruct the three-dimensional structure of trabecula in the region of interest;The trabecula in the three-dimensional structure image of trabecula is polished and smoothed;Convert to entity after being wrapped using fluid domain;Two-dimensional surface mesh subdivision is carried out to fluid domain, and three-dimensional body mesh division is carried out after subdivision to fluid domain;Trabecula is divided into three-dimensional body mesh;With fluid domain as cement, obtain the trabecula-cement composite of preset filling depth, respectively give cement, trabecula grid corresponding material attribute and material parameter, set boundary condition, load and the contact type between cement and trabecula, obtain trabecula-cement composite finite element model.The method of the present application omits the process of traditional construction trabecula-cement composite sample, and the finite element model established is high in accuracy, low in cost and easy to popularize.

Description

Technical Field

[0001] This invention relates to the field of finite element model construction technology, specifically to a method for constructing a finite element model of a trabecular bone-bone cement composite. Background Technology

[0002] In existing technologies, there are two main methods for establishing finite element models of the trabecular bone-cement interface:

[0003] Method 1: 1. Obtain human cadaver bone reinforced with bone cement and drill out a trabecular-bone cement composite sample; 2. Perform Micro-CT scanning on the trabecular-bone cement composite sample to obtain image data; 3. Reverse engineer the sample using computer to reconstruct a computer 3D model; 4. Create a volume mesh, assign material properties and parameters, set boundary conditions and loads, and perform finite element mechanical analysis.

[0004] Method 2: 1. Obtain human cadaver bone and drill out trabecular bone samples; 2. Inject bone cement into the trabecular bone; 3. After the bone cement has completely solidified, perform a Micro-CT scan on the trabecular bone-bone cement composite sample; the remaining steps are the same as in Method 1.

[0005] like Figure 1 The image shown is a schematic diagram illustrating the process of constructing a finite element model of a trabecular-cement composite after obtaining scanned images from a Micro-CT scan of the trabecular-cement composite sample.

[0006] The existing methods for constructing finite element models of trabecular-cement composites have the following drawbacks: 1. The trabecular bone obtained from cadaveric bone reinforced with bone cement often exhibits varying degrees of osteolysis and resorption, leading to numerous pores. This necessitates reverse filling in computer software to obtain a 3D model showing complete contact between the trabecular bone and bone cement, a complex and time-consuming process. 2. The grayscale thresholds of the trabecular bone and bone cement partially overlap, making it easy to misclassify them during separation in computer software. 3. The source of cadaveric bone reinforced with bone cement is very limited, and the high cost of cadaveric bone hinders its widespread application. 4. Artificially injected bone cement still retains a certain number of pores, affecting the accuracy of the finite element analysis; the 3D model still requires manual reverse filling. Summary of the Invention

[0007] To address the above problems, this invention provides a method for constructing a finite element model of a trabecular-bone cement composite.

[0008] The method for constructing a finite element model of a trabecular bone-cement composite provided by this invention includes:

[0009] Acquire microscopic imaging data of trabecular bone;

[0010] selecting a region of interest in the trabecular micro-image data, reconstructing a three-dimensional structure of the trabeculae in the region of interest, and obtaining a three-dimensional structure image of the trabeculae;

[0011] smoothing the trabeculae in the three-dimensional structure image of the trabeculae;

[0012] wrapping the smoothed trabeculae with the fluid domain according to the set fluid domain parameters, and converting the wrapped trabeculae into a solid;

[0013] setting a mesh size, selecting the fluid domain, performing two-dimensional surface mesh subdivision on the fluid domain, and performing three-dimensional solid mesh division on the fluid domain after the subdivision;

[0014] selecting the trabeculae, and performing three-dimensional solid mesh division on the trabeculae;

[0015] performing partial clipping and deletion on the divided fluid domain mesh, taking the fluid domain as bone cement, obtaining a trabecula-bone cement composite with a preset filling depth, assigning corresponding material properties and material parameters to the bone cement and trabecula mesh in the trabecula-bone cement composite, setting boundary conditions, loads, and contact types between the bone cement and the trabeculae, and obtaining a trabecula-bone cement composite finite element model.

[0016] Further, obtaining the trabecular micro-image data includes:

[0017] performing high-resolution peripheral quantitative CT scanning on the human body;

[0018] or, performing Micro-CT scanning on animal bone specimens or discarded bone specimens generated during orthopedic surgery.

[0019] Further, if the trabecular micro-image data is obtained by high-resolution peripheral quantitative CT scanning, selecting a region of interest in the trabecular micro-image data, reconstructing a three-dimensional structure of the trabeculae in the region of interest, and obtaining a three-dimensional structure image of the trabeculae includes:

[0020] importing the trabecular micro-image data into Mimics software, adjusting the window width and window level to select the region of interest, performing threshold segmentation and region growing operations in the region of interest, removing isolated structural units, obtaining a three-dimensional structure image of the trabeculae with clear boundaries, and saving the image as an STL format file;

[0021] If the trabecular micro-image data is obtained by Micro-CT scanning, selecting a region of interest in the trabecular micro-image data, reconstructing a three-dimensional structure of the trabeculae in the region of interest, and obtaining a three-dimensional structure image of the trabeculae includes:

[0022] The trabecular micro-image data is imported into the CTAn software, the upper and lower boundaries of the trabecular micro-image data are selected, the region of interest is selected, the region of interest is binarized, a three-dimensional structure image of the trabecula is obtained, and the three-dimensional structure image of the trabecula is saved as an STL format file.

[0023] Further, the trabecula in the three-dimensional structure image of the trabecula is polished and smoothed as follows:

[0024] The three-dimensional structure image of the trabecula is imported into the Geomagic studio software, the trabecula in the three-dimensional structure image of the trabecula is polished and smoothed by using the Geomagic studio software, and the three-dimensional structure image of the trabecula after polishing and smoothing is saved as an STL format file.

[0025] The polishing and smoothing processing includes: automatically analyzing and repairing the trabecula model, filling holes, deleting spikes, and redrawing the two-dimensional face mesh of the trabecula.

[0026] Further, according to the set fluid domain parameters, the polished and smoothed trabecula is wrapped with the fluid domain and converted into a solid as follows:

[0027] The three-dimensional structure image of the trabecula after polishing and smoothing is imported into the ANSYS 19.0 software, the fluid domain parameters are set in the ANSYS 19.0 software, the polished and smoothed trabecula is wrapped with the fluid domain according to the set fluid domain parameters, and the wrapped three-dimensional structure image of the trabecula is converted into a solid and saved as an STL format file.

[0028] Further, the mesh size is set, the fluid domain is selected, the fluid domain is two-dimensionally meshed, and the fluid domain is three-dimensionally meshed after the subdivision as follows:

[0029] The three-dimensional structure image of the wrapped trabecula is imported into the Hypermesh 14.0 software, the mesh size is set by using the Hypermesh 14.0 software, the fluid domain is selected, the fluid domain is two-dimensionally meshed, and the fluid domain is three-dimensionally meshed after the subdivision.

[0030] Further, the trabecula is selected, and the trabecula is three-dimensionally meshed as follows:

[0031] In the Hypermesh 14.0 software, the trabecula is selected, and the trabecula is three-dimensionally meshed.

[0032] Further, the fluid domain grid after division is partially cut and deleted, the fluid domain is taken as bone cement, the trabecula-bone cement complex with a preset filling depth is obtained, the bone cement and the trabecula grid in the trabecula-bone cement complex are respectively given corresponding material properties and material parameters, boundary conditions, loads and the contact type between the bone cement and the trabecula are set, and the trabecula-bone cement complex finite element model is obtained as follows:

[0033] In the Hypermesh 14.0 software, the fluid domain grid after division is partially cut and deleted, the fluid domain is taken as bone cement, the trabecula-bone cement complex with a preset filling depth is obtained, the bone cement and the trabecula grid in the trabecula-bone cement complex are respectively given corresponding material properties and material parameters, boundary conditions, loads and the contact type between the bone cement and the trabecula are set, and the trabecula-bone cement complex finite element model is obtained.

[0034] Further, the fluid domain parameters include fluid domain length, fluid domain width and fluid domain height.

[0035] Further, the material properties and material parameters include elastic modulus and Poisson's ratio.

[0036] The trabecula-bone cement complex finite element model construction method provided by the application has at least the following beneficial effects:

[0037] (1) The construction method provided by the application does not need to obtain / prepare a trabecula-bone cement complex sample in advance, but only needs to obtain trabecula micro-image data to perform the remaining trabecula-bone cement complex finite element model construction steps, and the operation is fast, simple, low in cost and easy to popularize.

[0038] (2) The construction method provided by the application does not need to use bone cement to strengthen and fix a cadaver bone to obtain a trabecula-bone cement complex sample, the established finite element model does not have a pore problem, the trabecula and the bone cement are completely attached, the precision of the finite element analysis is improved, and the analysis result is high in precision. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description only some embodiments of the application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of these drawings.

[0040] Figure 1 It is a schematic diagram of the construction process of the trabecula-bone cement complex finite element model in the prior art.

[0041] Figure 2 A flow chart of a method for constructing a trabecular bone-cement composite finite element model in an embodiment of the present application is shown in FIG. 1.

[0042] Figure 3 A flow chart of a method for constructing a trabecular bone-cement composite finite element model in an embodiment of the present application is shown in FIG. 1. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort are within the protection scope of the present application.

[0044] In an embodiment of the present application, a method for constructing a trabecular bone-cement composite finite element model is provided, as shown in FIG. 1, the method comprises the following steps: Figure 2

[0045] Step S1: obtaining trabecular bone micro-image data;

[0046] The trabecular bone micro-image data can be obtained by performing high-resolution peripheral quantitative CT (HR-qCT) scanning on a human body. Specifically, the human body is placed in a supine position with straight lower limbs, a solid phantom is added under the waist, and spiral scanning is performed on the L1-L5 vertebral bodies from the proximal end to the distal end. During the scanning process, the scanning line is parallel to the upper and lower edges of the vertebral body, the scanning resolution is 40-60 μm, and the trabecular bone image data obtained by scanning is saved in a standard DICOM format.

[0047] The trabecular bone micro-image data can also be obtained by performing Micro-CT scanning on animal bone specimens or discarded bone specimens generated during orthopedic surgery.

[0048] Specifically, the specific steps of performing Micro-CT scanning on animal bone specimens are as follows: after the SD rats are sacrificed by anesthesia or cervical dislocation, the bone specimens (such as femur, tibia, lumbar vertebrae, etc.) are quickly removed from the body, fixed with 4% paraformaldehyde for 48-72 hours, and then Micro-CT scanning is performed. The scanning direction is perpendicular to the longitudinal axis of the bone from the proximal end to the distal end of the bone, the scanning resolution is 15 μm, and the trabecular bone micro-image data obtained by scanning is saved in BMP format.

[0049] ​The specific steps of Micro-CT scanning of the waste bone specimens (such as femoral head) generated in the process of orthopedic surgery are as follows: collect the femoral head specimens in the process of hip replacement surgery of patients with hip fracture, fix the specimens with 4% paraformaldehyde for 48-72 hours, then perform Micro-CT scanning, the scanning direction is perpendicular to the longitudinal axis of the femoral neck from the proximal end to the distal end of the femoral head, the scanning resolution is 40 μm, and the trabecular micro-image data is saved in BMP format.

[0050] The trabecular micro-image data includes a plurality of trabecular micro-image images.

[0051] Step S2: selecting a region of interest in the trabecular micro-image data, and reconstructing the three-dimensional structure of the trabeculae in the region of interest to obtain a trabecular three-dimensional structure image.

[0052] If the trabecular micro-image data is obtained by high-resolution peripheral quantitative CT (HR-qCT) scanning of the human body, step S2 is specifically as follows: importing the trabecular micro-image data into Mimics software, adjusting the window width and window level (i.e. adjusting the size and position of the region of interest), and selecting the region of interest on the trabecular micro-image. Threshold segmentation and region growing operations are performed in the region of interest to remove isolated structural units, and a clear boundary trabecular three-dimensional structure image is obtained and saved as an STL format file.

[0053] The threshold segmentation in the region of interest is performed according to a preset threshold value to segment the trabeculae in the region of interest from the background. After threshold segmentation, the region growing function in the Mimics software is used to remove isolated structural units, and a clear boundary trabecular three-dimensional structure image is obtained.

[0054] If the trabecular micro-image data is obtained by Micro-CT scanning of animal bone specimens or waste bone specimens generated in the process of orthopedic surgery, step S2 is specifically as follows: importing the trabecular micro-image data into CTAn software, selecting the upper and lower boundaries of the trabecular micro-image set, selecting the region of interest, binarizing the region of interest, obtaining a trabecular three-dimensional structure image, and saving the trabecular three-dimensional structure image as an STL format file.

[0055] The trabecular micro-image set refers to a collection of a plurality of trabecular micro-image images included in the trabecular micro-image data. The purpose of selecting the upper and lower boundaries is to determine the height of the model (i.e. the height of the region of interest), such as Figure 3 The height of the yellow rectangle in A is determined by selecting the upper and lower boundaries.

[0056] Further, after selecting the region of interest and binarizing the region of interest, the morphological parameters of the trabeculae in the region of interest can also be derived.

[0057] The morphological parameters of the trabecula in the region of interest include a trabecular volume fraction BV / TV, a trabecular thickness, a trabecular number, and the like, which are used to quantitatively describe the trabecular structure quality. The morphological parameters of the trabecula in the region of interest are saved, and subsequent structural differences between different regions of interest can be compared and statistically analyzed.

[0058] As shown in FIG. 1B, the region of interest selected in the square in A in FIG. 1A is the region of interest. Figure 3

[0059] Step S3: polishing and smoothing the trabecula in the trabecular three-dimensional structure image.

[0060] The polishing and smoothing of the trabecula in the trabecular three-dimensional structure image includes the following steps.

[0061] The trabecular three-dimensional structure image is imported into the Geomagic studio software, the trabecula in the trabecular three-dimensional structure image is polished and smoothed by using the Geomagic studio software, and the trabecula after polishing and smoothing is saved as an STL format file. After polishing and smoothing, a smooth outer surface is obtained, and a two-dimensional surface mesh is automatically generated on the outer surface when the STL format file is saved in the Geomagic studio software.

[0062] The polishing and smoothing includes the following steps: using the mesh doctor command to automatically analyze and repair the trabecula model, filling holes, deleting spikes, and redrawing the two-dimensional surface mesh of the trabecula (refining the size of the two-dimensional surface mesh and making it uniformly distributed, with a size of 0.04 mm). When saved as an STL format file, a two-dimensional surface mesh is automatically generated on the outer surface of the trabecula (i.e., the two-dimensional surface mesh of the trabecula is redrawn).

[0063] As shown in FIG. 1B, B in FIG. 1B is the trabecular three-dimensional structure image obtained after polishing and smoothing. Figure 3

[0064] Step S4: wrapping the polished and smoothed trabecula with a fluid domain according to the set fluid domain parameters, and converting it into a solid.

[0065] The step S4 specifically includes the following steps: importing the polished and smoothed trabecular three-dimensional structure image into the ANSYS 19.0 software, setting the fluid domain parameters in the ANSYS 19.0 software, wrapping the polished and smoothed trabecula with a fluid domain according to the set fluid domain parameters, and converting it into a solid to obtain a wrapped trabecular three-dimensional structure image and save it as an STL format file. ​​

[0066] In the ANSYS 19.0 software, the trabecular three-dimensional structure image is opened by the SpaceClaim module, the trabeculae are wrapped by selecting the "enclosure" function, the fluid domain parameters are set, and the wrapped trabecular three-dimensional structure image is converted into a solid to obtain a wrapped trabecular three-dimensional structure image and save it as an STL format file.

[0067] The fluid domain parameters include the fluid domain length, the fluid domain width, and the fluid domain height.

[0068] As shown in FIG. 1C, C is the wrapped trabecular three-dimensional structure image. Figure 3

[0069] Step S5: setting a mesh size, selecting the fluid domain, performing two-dimensional surface mesh subdivision on the fluid domain, and performing three-dimensional body mesh division on the fluid domain after the subdivision.

[0070] The step S5 specifically includes: importing the wrapped trabecular three-dimensional structure image into the Hypermesh 14.0 software, setting the mesh size by using the Hypermesh 14.0 software, selecting the fluid domain, performing two-dimensional surface mesh subdivision on the fluid domain, and performing three-dimensional body mesh division on the fluid domain after the subdivision.

[0071] The mesh size setting is based on mesh convergence analysis, i.e. mesh independence verification. In this embodiment, based on the mesh convergence analysis, the mesh size can be set to 0.04 mm. At the same time, in this embodiment, the mesh size setting is to select the "automesh" function in the "2D" tab of the Hypermesh 14.0 software menu bar, so as to set the mesh size.

[0072] After setting the mesh size, the fluid domain is still selected under the "automesh" function to perform two-dimensional surface mesh subdivision, so as to obtain a uniformly distributed two-dimensional surface mesh and provide a template for the next three-dimensional body mesh division. As shown in FIG. 1D. Figure 3

[0073] After the subdivision, the three-dimensional body mesh division is performed on the fluid domain by selecting the "tetramesh" function in the "3D" tab of the Hypermesh 14.0 software menu bar, selecting "Tetra mesh", and selecting the fluid domain.

[0074] Step S6: selecting the trabeculae, performing three-dimensional body mesh division on the trabeculae;

[0075] ​​Similarly, the three-dimensional body mesh division of the trabeculae in this step is also achieved by selecting the 'tetramesh' function in the '3D' tab of the menu bar of the Hypermesh 14.0 software, selecting 'Tetra mesh', and selecting the trabeculae, so as to perform the three-dimensional body mesh division on the trabeculae.

[0076] The body mesh division in steps S5 and S6 is automatically performed by the Hypermesh 14.0 software according to the Boolean logic operation to automatically distinguish the fluid domain and the trabeculae and to automatically fill the gaps between the trabeculae. Figure 3

[0077] Step S7: Partially cutting and deleting the divided fluid domain mesh, taking the fluid domain as the bone cement, obtaining the trabecula-bone cement composite with a preset filling depth, respectively giving the bone cement and the trabecula mesh in the trabecula-bone cement composite corresponding material properties and material parameters, setting boundary conditions, loads and the contact type between the bone cement and the trabeculae, and obtaining the trabecula-bone cement composite finite element model.

[0078] Step S7: Partially cutting and deleting the divided fluid domain mesh, taking the fluid domain as the bone cement, obtaining the trabecula-bone cement composite with a preset filling depth, respectively giving the bone cement and the trabecula mesh in the trabecula-bone cement composite corresponding material properties and material parameters, setting boundary conditions, loads and the contact type between the bone cement and the trabeculae, and obtaining the trabecula-bone cement composite finite element model. Figure 3

[0079] Further, the preset filling depth is set by the technician according to the actual needs, and the present application does not limit this.

[0080] The material properties include solid, pipe, shell and the like.

[0081] The material parameters include elastic modulus, Poisson's ratio and density. The contact type between the bone cement and the trabeculae includes friction and binding.

[0082] The material properties and the material parameters, the setting of the boundary conditions, the loads and the contact type between the bone cement and the trabeculae are all set by the technician according to the actual needs, and the present application does not limit this.

[0083] More specifically, in the Hypermesh 14.0 software, the 'delete' function is selected in the 'Tool' tab of the menu bar, and the bone cement mesh (i.e. the fluid domain mesh) is partially cut and deleted, so as to obtain the trabecula-bone cement composite with a preset filling depth.

[0084] ​​Further, when the trabecular bone-cement composite finite element model is obtained, the model can be calculated and solved to obtain corresponding experimental data such as displacement and stress. Figure 3 G.

[0085] The trabecular bone-cement composite finite element model construction method provided by the application does not need to obtain or prepare a trabecular bone-cement composite sample when constructing the finite element model, only needs to obtain trabecular bone micro-image data, and subsequently reconstructs a trabecular bone three-dimensional model by using the trabecular bone micro-image data, wraps a fluid domain outside the trabecular bone, takes the fluid domain as cement, and finally obtains the trabecular bone-cement composite finite element model. The human cadaver bone is not needed, so the cost is greatly reduced. In the process of generating the trabecular bone-cement composite finite element model, there is no problem of bone resorption or bone absorption, and there is no problem of generation of a large number of pores caused by artificial perfusion of cement, so reverse filling is not needed, and the operation is fast, simple and convenient, and is easy to popularize. At the same time, there is no problem of partial overlap of the gray scale threshold of the trabecular bone and the cement, and there is no problem of error distribution when modeling separates the two. The established finite element model has no pore problem, the trabecular bone and the cement are completely attached, the accuracy of the finite element analysis is improved, and the analysis result is high in accuracy.

[0086] The terms and phrases used in the specification of the present application are only for example and do not mean limitation. Those skilled in the art should understand that various changes can be made to the details of the above-mentioned embodiments without departing from the basic principles of the disclosed embodiments. Therefore, the scope of the present application is only determined by the claims, and in the claims, unless otherwise stated, all terms should be understood in the broadest reasonable sense.

Claims

1. A method for constructing a finite element model of a trabecular bone-cement composite, characterized by, The method comprises: obtaining trabecular bone micro-image data; selecting a region of interest in the trabecular bone micro-image data, reconstructing a three-dimensional structure of the trabecular bone in the region of interest, and obtaining a trabecular bone three-dimensional structure image; smoothing the trabecular bone in the trabecular bone three-dimensional structure image; wrapping the smoothed trabecular bone with a fluid domain according to the set fluid domain parameters, and converting the wrapped trabecular bone into a solid; setting a grid size, selecting the fluid domain, performing two-dimensional surface mesh subdivision on the fluid domain, and performing three-dimensional volume mesh division on the fluid domain after the subdivision; selecting the trabecular bone, and performing three-dimensional volume mesh division on the trabecular bone; performing partial clipping and deletion on the divided fluid domain grid, taking the fluid domain as bone cement, obtaining a trabecular bone-bone cement composite with a preset filling depth, and giving the bone cement and trabecular bone grid in the trabecular bone-bone cement composite corresponding material properties and material parameters, setting boundary conditions, loads, and contact types between the bone cement and the trabecular bone, to obtain a trabecular bone-bone cement composite finite element model.

2. The method of claim 1, wherein, The method comprises: performing high-resolution peripheral quantitative CT scanning on a human body; or, performing Micro-CT scanning on animal bone specimens or discarded bone specimens generated during orthopedic surgery.

3. The method of claim 2, wherein the method further comprises: If the trabecular bone micro-image data is obtained by high-resolution peripheral quantitative CT scanning, the method of selecting a region of interest in the trabecular bone micro-image data, reconstructing a three-dimensional structure of the trabecular bone in the region of interest, and obtaining a trabecular bone three-dimensional structure image comprises: importing the trabecular bone micro-image data into Mimics software, adjusting the window width and window level to select a region of interest, performing threshold segmentation and region growing operations in the region of interest, removing isolated structural units, obtaining a trabecular bone three-dimensional structure image, and saving the image as an STL format file; If the trabecular bone micro-image data is obtained by Micro-CT scanning, the method of selecting a region of interest in the trabecular bone micro-image data, reconstructing a three-dimensional structure of the trabecular bone in the region of interest, and obtaining a trabecular bone three-dimensional structure image comprises: importing the trabecular bone micro-image data into CTAn software, selecting the upper and lower boundaries of the trabecular bone micro-image data, selecting a region of interest, binarizing the region of interest, obtaining a trabecular bone three-dimensional structure image, and saving the image as an STL format file.

4. The method of claim 3, wherein, The smoothing of the trabecular bone in the trabecular bone three-dimensional structure image comprises: importing the trabecular bone three-dimensional structure image into Geomagic studio software, smoothing the trabecular bone in the trabecular bone three-dimensional structure image using the Geomagic studio software, and saving the smoothed trabecular bone three-dimensional structure image as an STL format file; wherein the smoothing comprises automatically analyzing and repairing the trabecular bone model, filling holes, deleting spikes, and redrawing the two-dimensional surface mesh of the trabecular bone.

5. The method of claim 4, wherein, The wrapping of the smoothed trabecular bone with a fluid domain according to the set fluid domain parameters, and the conversion of the wrapped trabecular bone into a solid, comprises: The polished smooth trabecular bone three-dimensional structure image is imported into ANSYS 19.0 software, fluid domain parameters are set in the ANSYS 19.0 software, the polished smooth trabecular bone is wrapped by using the fluid domain after the polished smooth trabecular bone is wrapped by using the fluid domain, and a wrapped trabecular bone three-dimensional structure image is obtained and saved as an STL format file.

6. The method of claim 5, wherein, The grid size is set, the fluid domain is selected, the fluid domain is subjected to two-dimensional surface mesh subdivision, and the fluid domain is subjected to three-dimensional body mesh division after the subdivision. The wrapped trabecular bone three-dimensional structure image is imported into Hypermesh 14.0 software, the grid size is set by using the Hypermesh 14.0 software, the fluid domain is selected, the fluid domain is subjected to two-dimensional surface mesh subdivision, and the fluid domain is subjected to three-dimensional body mesh division after the subdivision.

7. The method of claim 6, wherein the method further comprises: The trabecular bone is selected, and the trabecular bone is subjected to three-dimensional body mesh division. In the Hypermesh 14.0 software, the trabecular bone is selected, and the trabecular bone is subjected to three-dimensional body mesh division.

8. The method of claim 7, wherein the method further comprises: The divided fluid domain grid is partially cut and deleted, the fluid domain is used as bone cement, a trabecular bone-bone cement composite with a preset filling depth is obtained, the bone cement and the trabecular bone grid in the trabecular bone-bone cement composite are respectively given corresponding material properties and material parameters, boundary conditions, loads and the contact type between the bone cement and the trabecular bone are set, and a trabecular bone-bone cement composite finite element model is obtained. In the Hypermesh 14.0 software, the divided fluid domain grid is partially cut and deleted, the fluid domain is used as bone cement, a trabecular bone-bone cement composite with a preset filling depth is obtained, the bone cement and the trabecular bone grid in the trabecular bone-bone cement composite are respectively given corresponding material properties and material parameters, boundary conditions, loads and the contact type between the bone cement and the trabecular bone are set, and a trabecular bone-bone cement composite finite element model is obtained.

9. The method of claim 1, wherein, The fluid domain parameters include fluid domain length, fluid domain width and fluid domain height.

10. The method of claim 1, wherein, The material parameters include elastic modulus and Poisson's ratio.

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