A method for generating a human biomechanical model

Abstract

This application belongs to the field of numerical modeling, and particularly relates to a method for generating a human biomechanical model. By using anatomical and inverse modeling methods, geometric models of the human body at different ages are obtained. Through the matching of only several geometric feature points, the rapid mapping generation of the human biomechanical model corresponding to the age can be quickly completed, greatly reducing the difficulty of generating the human biomechanical model of other ages, improving the modeling efficiency, and at the same time ensuring the accuracy of the generated human mesh model. Based on anatomy, highly realistic biomechanical models of key impact parts such as the head, neck, and chest are established. Then, referring to the connection methods of human organs / tissues, the connection between the head and the neck, and between the neck and the chest is realized. On this basis, physical verification of the model effectiveness is carried out to ensure the accuracy and reliability of the model.

Description

Technical Field

[0001] This application belongs to the field of numerical modeling, and particularly relates to a method for generating a human biomechanical model. Background Art

[0002] In recent years, the light and small unmanned aerial vehicle (UAV) industry has developed vigorously and been widely used in many fields, reshaping the working and living paradigms of people. UAV manufacturers represented by DJI occupy an absolute dominant position in the global market, and the UAV industry has become another beautiful business card in the industrial field. At the same time, during the operation of UAVs, there is spatio-temporal overlap with ground personnel, etc., resulting in frequent collision accidents. There are thousands of collision cases globally every year, causing widespread concern among the public. Successive flight restrictions and control requirements have become major challenges restricting the sustainable and healthy development of the UAV industry. Therefore, it is urgent to carry out UAV collision safety assessment to evaluate the injury conditions of the human body during the UAV impact process. Using human volunteers or physical dummies to carry out collision injury analysis and evaluation, although this method can relatively accurately obtain the human impact response and injury conditions, there are problems such as difficulties in carrying out the test, high test costs, incomplete obtained parameters, and long test cycles.

[0003] With the development and breakthrough of computer simulation technology, digital modeling based on in-vivo data has gradually become the first choice for scientific research. A human biomechanical model is a method of simulating the organizational structure of the human body for research. Its purpose is to analyze the interaction between various parts of the human body, and it can accurately evaluate the response of various parts of the human body tissues to load effects in a numerical simulation manner that relatively conforms to human ethical norms, so as to meet the needs of quantitative analysis of the human body system in various application fields. For carrying out UAV collision personnel injury analysis, in addition to improving the research efficiency and economy, it can also obtain physical quantities that cannot be measured through experiments, quantitatively reveal the force transmission path and deformation degree during the human body being collided, and clarify the laws and injury degrees of human body being collided and injured.

[0004] Therefore, how to establish a human biomechanical model that can quantitatively reveal the force transmission path and deformation degree during the human body being collided is a problem that needs to be solved. Summary of the Invention

[0005] The purpose of this application is to provide a method for generating a human biomechanical model to solve the problem in the prior art that it is difficult to quantitatively reveal the force transmission path and deformation degree during the human body being collided.

[0006] The technical solution of this application is: A method for generating a human biomechanical model, comprising:

[0007] Determine the human body parts that need to be reconstructed, conduct a requirements analysis, and obtain different human organs and their tissues required for different human body parts; acquire existing medical image data for image segmentation and classification, and then, based on the segmented data of different categories of images, separately model different human organs and their tissues, and assemble them to obtain an anatomical-based geometric model of the upper human body; the geometric model of the upper human body includes geometric models of various tissues of the human body, a geometric model of the human head, a geometric model of the human neck, and a geometric model of the human chest.

[0008] Perform mesh division on the geometric model of the upper human body. Based on anatomical features, establish a hexahedral mesh model for each bone and tissue of the upper human body, a quadrilateral shell element for the skin, and a spring element for the neck muscles. After splicing, obtain a refined mesh model of the upper human body.

[0009] On the basis of the established geometric model of the upper human body, based on the radial basis theory, establish the corresponding relationship of key landmark points in the geometric models of the upper human body of different age groups; first perform human mesh transformation to obtain the target human mesh models of each part, and then splice the target human mesh models of each part to generate human biomechanical models of different age groups.

[0010] According to the refined mesh model of the upper human body and the human biomechanical models of different age groups, combined with the existing test data of volunteers, conduct collision analysis for the three parts of the head, neck, and chest respectively, and perform model correction and verification to obtain a corrected human biomechanical model.

[0011] For the selected UAV product, establish a corresponding target finite element mesh model, carry out analysis conditions such as hitting the top of the head at the maximum speed of falling, hitting the forehead point horizontally at the maximum speed, and hitting the chest at the maximum speed, extract the sensor response data of the corrected human biomechanical model, and evaluate the degree of human injury according to the human injury criterion.

[0012] Preferably, the modeling method of the geometric model of each tissue of the human body is as follows:

[0013] Using the image segmentation method, separate the skin, bones, muscles, brain, and ligament tissues of different parts to obtain the segmented images.

[0014] Based on the segmented images, perform geometric reconstruction on the medical image data points through the threshold segmentation method, and according to the shape characteristics of different parts, organs, and tissues of the human body, conduct geometric segmentation with reference to the anatomical atlas to separately obtain the geometric models of each tissue of the human body.

[0015] Preferably, perform geometric cleaning on the geometric models of each tissue of the human body until the surface self-intersection, highly refractive edges, and small holes inside the geometry are eliminated.

[0016] Preferably, the specific steps for establishing a hexahedron mesh model are as follows:

[0017] Import the geometric model of the upper body of the human body into Truegrid software, open the geometric model of the upper body of the human body in IGES format, and obtain the point, line, and surface data of the geometric model of the upper body of the human body;

[0018] Define blocks according to the point, line, and surface data of the geometric model of the upper body of the human body until the mesh is evenly distributed in the X, Y, and Z directions. Adjust the shape of the block to be consistent with the geometric model of the upper body of the human body, and move the block to the position of the centroid of the geometric model of the upper body of the human body to obtain the boundary points of the block on the mesh;

[0019] Project the boundary points of the block on the mesh to the geometric boundary, project the line connecting any two points in the block to the geometric boundary line, and finally project the plane enclosed by the four sides of the block to the mesh surface to obtain a hexahedron mesh model.

[0020] Preferably, the quadrilateral shell elements are obtained by constructing a ligament model in a combined manner of shell elements that reflect the true geometric shape of the ligament and simplified discrete beams according to the anatomical atlas; the spring elements are obtained by analyzing the muscle fiber bundles and simplifying the muscles into spring elements for modeling.

[0021] Preferably, after the hexahedron mesh model, quadrilateral shell elements, and spring elements are established, based on the anatomical structure, splice the established geometric models of the human head, human neck, and human chest to generate a refined mesh model of the upper body of the human body.

[0022] Preferably, perform a mesh quality inspection on the established refined mesh model of the upper body of the human body. Use the geometric integrity inspection method to obtain the Jacobian, warping degree, distortion degree, and aspect ratio of the mesh, set the evaluation index of the mesh quality, and judge whether there are mesh penetration and interference problems between the connected parts of the mesh and inside each part of the mesh. If the requirements of the evaluation index of the mesh quality are met, it is judged that there are no mesh penetration and interference problems; the evaluation index of the mesh quality includes: for the hexahedron mesh model, the number of meshes with a Jacobian of more than 0.4 ≥ 99%, the number of meshes with a warping degree of less than 40 ≥ 99%, the number of meshes with a distortion degree of less than 50 ≥ 95%, and the number of meshes with an aspect ratio of less than 5 ≥ 95%; for the quadrilateral shell elements, the number of meshes with a Jacobian of more than 0.3 ≥ 99%, the number of meshes with a warping degree of less than 40 ≥ 99%, the number of meshes with a distortion degree of less than 50 ≥ 99%, and the number of meshes with an aspect ratio of less than 3 ≥ 99%.

[0023] Preferably, the method for establishing the target finite element mesh model is as follows:

[0024] Take the geometric model of the upper body of a human body in other age groups outside the current age group as the target geometric model; extract a certain number of landmark points in the geometric model of the upper body of the human body as the reference landmark points ( x i , y i , z i ), and at the same time extract the landmark points corresponding to the reference landmark points on the target geometric model as the target landmark points ( x j , y j , z j ); assume that the number of extracted reference landmark points and target landmark points is n , and the total number of nodes in the refined mesh model of the upper body of the human body is N ; the coordinates of the transformed target geometric model are denoted as ( M, P, Q );

[0025] Calculate the distance between corresponding two points through the Euclidean norm r and substitute it into the basis function. Using the coordinate information of the basic geometric model, construct a matrix , where A is a parameter, is the transpose of P;

[0026] According to the coordinate information of the target landmark points of the target geometric model, calculate the column vectors , and of the interpolation weight coefficients, and the calculation formula for the nodes of the target finite element mesh model of each part is:

[0027] ;

[0028] In the formula, , , , are all column vectors, and is a fixed parameter;

[0029] Use the column vectors composed of different interpolation weight coefficients and the coordinate parameters of all nodes of the refined mesh model of the upper body of the human body to perform the optimal solution mapping between the reference landmark points and the target landmark points, and obtain three column vectors M, P, and Q of the coordinates of the target finite element mesh model of each part after interpolation. Construct the target finite element mesh model through the three column vectors M, P, and Q.

[0030] Preferably, based on the upper body geometric model of the human body and the target geometric model, reference landmark points and target landmark points are selected and marked until the positions of the reference landmark points and the target landmark points correspond and the quantities are the same; the method of optimal solution mapping is specifically as follows: taking the one-to-one corresponding reference landmark points and target landmark points and the node coordinate information in the refined mesh model of the upper body of the human body as the input conditions for mesh transformation, calculating all the node coordinate information of the target finite element mesh model of each part, and keeping the element connection unchanged.

[0031] Preferably, the specific method for model correction and verification is as follows:

[0032] According to the volunteer head impact test condition parameters obtained from the biomechanical research test of craniocerebral injury, the same analysis conditions are set for collision analysis, and the accuracy of the human head geometric model is verified through the collision contact force curve to obtain the head test results;

[0033] According to the existing volunteer trolley test condition parameters, the same analysis conditions are set for collision analysis to obtain the cervical curve, and the accuracy of the human neck geometric model is verified through the cervical curve to obtain the neck test results;

[0034] According to the existing volunteer chest impact test condition parameters, the same analysis conditions are set for collision analysis to carry out the reliability verification of the human chest geometric model and obtain the chest test results;

[0035] According to the head, neck and chest test results, the human biomechanical model is corrected and confirmed.

[0036] The method for generating and transforming the human biomechanical model of the present application has the following advantages:

[0037] Based on anatomy and reverse modeling methods, human geometric models of different age groups are obtained. Only through the matching of several geometric feature points, the rapid mapping generation of the human biomechanical model of the corresponding age group can be quickly completed, greatly reducing the generation difficulty of the human biomechanical models of other age groups, improving the modeling efficiency, and at the same time ensuring the accuracy of the generated human mesh model.

[0038] Based on anatomy, high-fidelity biomechanical models of key impact parts such as the head, neck and chest are established. Then, referring to the connection methods of human organs / tissues, the connection between the head and the neck and the connection between the neck and the chest are realized. On this basis, the physical verification of the model effectiveness is carried out to ensure the accuracy and reliability of the model.

[0039] High-precision modeling is carried out on the head, neck and chest, simplified modeling is carried out on non-key parts such as the lower body, and mechanical response sensors are set, which can quickly extract the acceleration, displacement or force collision response time history curves of the typical parts of concern, facilitating the carrying out of collision damage analysis and evaluation. Brief Description of the Drawings

[0040] To more clearly illustrate the technical solutions provided in this application, the drawings will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application.

[0041] Figure 1 It is a schematic diagram of the overall process of this application;

[0042] Figure 2 It is a schematic diagram of the geometric model of the human head of this application;

[0043] Figure 3 It is a schematic diagram of the geometric model of the human neck of this application;

[0044] Figure 4 It is a schematic diagram of the geometric model of the human chest of this application;

[0045] Figure 5 It is a schematic diagram of the refined mesh model of the head of this application;

[0046] Figure 6 It is a flowchart for establishing the target finite element mesh model of this application. Detailed Embodiments

[0047] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0048] A method for generating a human biomechanical model. The process of generating a human biomechanical model proposed in this application takes an adult male at the 50th percentile as an example only. The methods for generating human models of other ages, genders, and body shapes are the same and will not be elaborated.

[0049] As Figure 1 , it includes the following steps:

[0050] Step S100, constructing a geometric model of the upper body of the human body:

[0051] Specifically: Determine the human body parts to be reconstructed, conduct a requirements analysis to obtain different human organs and their tissues required for different human body parts; obtain existing medical image data for image segmentation and classification, and then respectively model different human organs and their tissues by combining the segmented data of different categories of images, and then assemble to obtain an anatomical-based geometric model of the upper body of the human body. The geometric model of the upper body of the human body includes geometric models of various tissues of the human body, geometric models of the human head, geometric models of the human neck, and geometric models of the human chest.

[0052] The human body parts include the upper body parts and the remaining parts. The upper body parts are divided into the head, neck, and chest, and can be specifically subdivided into brain tissue, skull, scalp, cervical vertebrae, cervical intervertebral discs, cervical joints, thoracic vertebrae, ribs, sternum, scapulae, collarbones, chest soft tissues, etc. The remaining parts include the upper limbs, abdomen, lower limbs, etc., which are not the parts concerned in the study of collision injuries, and no anatomical-based human biomechanical modeling is carried out, and a simplified model is used instead.

[0053] Preferably, the means for obtaining existing data are: for different human organs and their tissues, medical images of the head, neck, and chest are obtained respectively based on CT or magnetic resonance imaging.

[0054] Preferably, the modeling method for the geometric models of tissues of each part of the human body is as follows:

[0055] Using the image segmentation method, tissues such as skin, bone, muscle, brain, ligament, etc. of different parts are separated to obtain the segmented image; ensure that the segmented image can completely reflect the structure and shape of the tissue and has sufficient biological fidelity;

[0056] Based on the segmented image, geometric reconstruction is performed on the medical image data points through the threshold segmentation method, and geometric segmentation is carried out according to the shape characteristics of different parts, different organs, and different tissues of the human body with reference to the anatomical atlas to obtain the geometric models of tissues of each part of the human body respectively;

[0057] Since there are hole defects in the human biological geometric surface obtained by the threshold segmentation method, the tissue model is further processed, specifically: geometric cleaning is carried out on the geometric models of tissues of each part of the human body until small structures such as surface self-intersection, highly refractive edges, and small holes inside the geometry are eliminated, and the geometric surface curvature is improved to obtain the geometric models of tissues of each part of the human body suitable for mesh modeling after repair.

[0058] Preferably, the established geometric model of the human head includes the skull, facial bones, head skin, brain tissue, cerebellar tissue, brainstem tissue, etc.; the established geometric model of the human neck includes 7 cervical vertebrae, intervertebral discs, ligaments, muscles, skin, etc.; the established geometric model of the human chest includes 12 thoracic vertebrae, 12 pairs of ribs, sternum, scapulae, collarbones, lung tissue, heart tissue, muscle tissue, skin tissue, diaphragm, etc., as Figures 2 - 4 .

[0059] Assemble the geometric models of tissues of each part of the human body, the geometric model of the human head, the geometric model of the human neck, and the geometric model of the human chest to complete the three-dimensional geometry construction of the head, neck, and chest, and form an anatomical-based geometric model of the upper half of the human body.

[0060] Step S200: Construct a refined mesh model of the upper body of the human body:

[0061] Specifically: Perform mesh division on the geometric model of the upper body of the human body. Based on anatomical features, establish hexahedral mesh models for each bone and tissue of the upper body of the human body, establish quadrilateral shell elements for the skin, etc., and establish spring elements for the neck muscles, etc. After splicing, a refined mesh model of the upper body of the human body is obtained.

[0062] Preferably, use Truegrid software to perform mesh division on the geometric model of the upper body of the human body; the specific steps for establishing a hexahedral mesh model are:

[0063] Import the geometric model of the upper body of the human body into Truegrid software, open the geometric model of the upper body of the human body in IGES format to obtain the point, line, and surface data of the geometric model of the upper body of the human body;

[0064] Define blocks according to the point, line, and surface data of the geometric model of the upper body of the human body until the mesh is evenly distributed in the X, Y, and Z directions. Adjust the shape of the block to be consistent with the geometric model of the upper body of the human body, and move the block to the position of the centroid of the geometric model of the upper body of the human body to obtain the boundary points of the block on the mesh;

[0065] Project the boundary points of the block on the mesh to the geometric boundary, project the line connecting any two points in the block to the geometric boundary line, and finally project the plane enclosed by the four sides of the block to the mesh surface to obtain a hexahedral mesh model; in the projection work of points, lines, and surfaces, the methods of lines and surfaces can be used to solve problems related to uneven mesh distribution, and the internal mesh can be smoothed by inserting nodes.

[0066] Preferably, for human ligament tissues, in accordance with anatomical atlases, a combination of shell elements and simplified discrete beams that can truly reflect the true geometric shape of the ligaments is used to construct ligament models to obtain quadrilateral shell elements. For human muscle tissues, the muscles are simplified into spring elements for modeling by analyzing muscle fiber bundles to obtain each spring element.

[0067] Preferably, after the hexahedral mesh model, quadrilateral shell elements, and spring elements are established, based on the anatomical structure, splice the established geometric models of the human head, human neck, and human chest to generate a refined mesh model of the upper body of the human body. Among them, the neck, as the part between the head and the chest, is connected to the head model through ligaments, muscles, etc. at the upper part and is connected to the chest model through intervertebral discs, ligaments, muscles, etc. at the lower part.

[0068] Preferably, for mechanical response parameters such as head acceleration, six-degree-of-freedom cervical spine force, thoracic compression, and thoracic acceleration that are the key focuses of collision analysis, acceleration sensors, force sensors, displacement sensors, etc. are respectively set at specified positions on the refined mesh model of the human upper body to extract the response time history signals during the collision analysis process.

[0069] Check the model quality. Perform a mesh quality check on the established refined mesh model of the human upper body. Try to improve the mesh quality as much as possible by manually adjusting the mesh nodes. Use the geometric integrity check method to check whether there are mesh penetration and interference problems between the connected parts of the mesh and inside each part of the mesh. Set the evaluation indexes of the mesh quality. Use the geometric integrity check method to obtain the main parameters of the mesh, as shown in Table 1. The main parameters include the Jacobian, warping degree, distortion degree, aspect ratio, etc. of the mesh. Control the calculation results and calculation time by controlling the evaluation indexes of the mesh quality. If the requirements of the evaluation indexes of the mesh quality are met, it is judged that there are no mesh penetration and interference problems.

[0070] For the abdomen and lower limb parts that are not concerned in the collision analysis, the corresponding parts of the mature and reliable Hybrid III 50th percentile adult dummy model are used for replacement and spliced with the established biomechanics of the human upper body to complete the final construction of the human whole body finite element model. The established refined mesh models of the head, neck, chest, upper body, and whole body, among which the refined mesh model of the head is as Figure 5 shown.

[0071] Table 1 Evaluation indexes of the mesh quality of human biological tissues

[0072]

[0073] Step S300, perform human model transformation based on the landmark mapping theory:

[0074] Specifically: Based on the established geometric model of the human upper body, establish the corresponding relationship of key landmarks in the geometric models of the human upper body of different age groups based on the radial basis theory. First, perform human mesh transformation to obtain the target finite element mesh models of each part, and then splice the target finite element mesh models of each part to generate the human biomechanical models of different age groups.

[0075] Preferably, as Figure 6 , the method for establishing the target finite element mesh model is:

[0076] Take the geometric model of the human upper body of other age groups except the current age group as the target geometric model; extract a certain number of landmarks in the geometric model of the human upper body as the reference landmarks ( x i ,y i , z i ), while extracting the corresponding landmark points on the target geometric model as the target landmark points ( x j , y j , z j ). Assume that the number of extracted reference landmark points and target landmark points is n , and the total number of nodes of the refined mesh model of the upper body of the human body is N . The coordinates of the transformed target geometric model are denoted as ( M, P, Q ).

[0077] , , .

[0078] Calculate the distance between the corresponding two points through the Euclidean norm r and substitute it into the basis function. Using the coordinate information of the basic geometric model, construct the matrix , where A is a parameter, is the transpose of P.

[0079] According to the coordinate information of the target landmark points of the target geometric model, calculate the column vectors , and of the interpolation weight coefficients. The calculation formula for the nodes of the target finite element mesh model of each part is:

[0080] (1)

[0081] In the formula, , , , are all column vectors, and is a fixed parameter.

[0082] Using the column vectors composed of different interpolation weight coefficients and the coordinate parameters of all nodes of the refined mesh model of the upper body of the human body, perform the optimal solution mapping of the reference landmark points and the target landmark points by calculating the minimum value of the surface energy equation, and then the three column vectors M, P, and Q of the coordinates of the target finite element mesh model of each part after interpolation can be obtained. The target finite element mesh model is constructed through the three column vectors M, P, and Q.

[0083] Preferably, the construction of the target geometric model is the same as the method for constructing the geometric model of the upper body of the human body in step S100, and is obtained by separately modeling different human organs and their tissues and then splicing the models.

[0084] Preferably, based on the upper body geometric model of the human body and the target geometric model, reference landmark points and target landmark points are selected and marked until the positions of the reference landmark points and the target landmark points correspond and the quantities are the same.

[0085] Preferably, the method of optimal solution mapping is specifically as follows: The one-to-one corresponding reference landmark points and target landmark points and the node coordinate information in the refined mesh model of the upper body of the human body are used as the input conditions for mesh transformation, and all the node coordinate information of the target finite element mesh model of each part is calculated, and the element connection remains unchanged.

[0086] The shapes and sizes of the human body geometric models of different age groups vary greatly, which may cause mesh distortion after transformation. Therefore, mesh quality optimization is required to obtain a high-quality target mesh model. The method of mesh quality optimization can adopt engineering simulation mesh optimization methods, etc.

[0087] The method of splicing the target finite element mesh models of each part is the same as the splicing method in step S200. Taking a 6-year-old child as an example, a human body biomechanical model of a 6-year-old child is obtained through the transformation method.

[0088] Step S400, verify the human body biomechanical model with high fidelity:

[0089] According to the refined mesh model of the upper body of the human body and the human body biomechanical models of different age groups, combined with the test data obtained through methods such as volunteer tests, collision analysis is carried out for three parts, namely the head, neck and chest, respectively, and model correction and verification are carried out to obtain the corrected human body biomechanical model.

[0090] Preferably, the specific method of model correction and verification is as follows:

[0091] According to the working condition parameters of the volunteer head impact test obtained from the Nahum test (biomechanical research test on craniocerebral injury), set the same analysis working conditions for collision analysis, verify the accuracy of the human head geometric model through the collision contact force curve, and obtain the head test results;

[0092] According to the existing working condition parameters of the volunteer trolley test, set the same analysis working conditions for collision analysis to obtain the cervical curve, and verify the accuracy of the human neck geometric model through the cervical curve to obtain the neck test results;

[0093] According to the existing working condition parameters of the volunteer chest impact test, set the same analysis working conditions for collision analysis, and carry out the reliability verification of the human chest geometric model to obtain the chest test results;

[0094] According to the head, neck and chest test results, correct and confirm the human body biomechanical model to ensure that the model analysis response curve falls within the test curve envelope range.

[0095] Step S500: Conduct simulation analysis and injury assessment of drone impact on human body:

[0096] For the selected drone product, establish a corresponding target finite element mesh model, conduct analysis scenarios of hitting the top of the head with the maximum speed drop, horizontally hitting the frontal point with the maximum speed, and hitting the chest with the maximum speed, extract the sensor response data of the corrected human biomechanical model, and evaluate the degree of human injury according to the human injury criterion.

[0097] In summary, the present application has the following advantages:

[0098] Based on anatomy and reverse modeling methods, human body geometric models of different age groups are obtained. Only through the matching of several geometric feature points, the rapid mapping generation of human biomechanical models corresponding to different age groups can be quickly completed, greatly reducing the generation difficulty of human biomechanical models of other age groups, improving the modeling efficiency, and at the same time ensuring the accuracy of the generated human body mesh model.

[0099] Based on anatomy, highly realistic biomechanical models of key impact parts such as the head, neck, and chest are established. Then, referring to the connection methods of human organs / tissues, the connection between the head and the neck, and between the neck and the chest is realized. On this basis, physical verification of the model effectiveness is carried out to ensure the accuracy and reliability of the model.

[0100] High-precision modeling is carried out for the head, neck, and chest, simplified modeling is carried out for non-key parts such as the lower body, and mechanical response sensors are set up, which can quickly extract the acceleration, displacement, or force collision response time history curves of the typical parts of concern, facilitating the conduct of collision injury analysis and assessment.

[0101] On the basis of establishing an adult model, the rapid mapping generation of models of human bodies of different ages (different sizes and weights) can be quickly realized, greatly reducing the generation difficulty of human biomechanical models of other age groups and improving the modeling efficiency.

[0102] Finally, it should be noted that: in the attached drawings of the disclosed embodiments of the present invention, only the structures related to the disclosed embodiments of the present disclosure are involved. For other structures, reference can be made to the general design. Without conflict, the same embodiment and different embodiments of the present invention can be combined with each other;

[0103] Finally: The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for generating a human biomechanical model, characterized in that: include: Determine the body parts that need to be reconstructed, conduct demand analysis, and obtain the different human organs and tissues required for different body parts; Obtain existing medical image data for image segmentation and classification, and then combine the segmented data of different categories of images to model different human organs and tissues respectively, and assemble to obtain an anatomically based upper body geometric model of the human body; the upper body geometric model of the human body includes geometric models of various parts of the human body, a human head geometric model, a human neck geometric model, and a human chest geometric model; The geometric model of the upper body of the human body is meshed. According to the anatomical characteristics, a hexahedral mesh model is established for each bone and tissue of the upper body of the human body, a quadrilateral shell unit is established for the skin, and a spring unit is established for the neck muscles. After splicing, a refined mesh model of the upper body of the human body is obtained; On the basis of the established human upper body geometric model, based on the radial basis theory, the correspondence between key landmarks in the human upper body geometric model of different age groups is established; firstly, the human body mesh transformation is performed to obtain the target human body mesh model of each part, and then the target human body mesh model of each part is spliced ​​to generate the human biomechanical models of different age groups; Based on the refined mesh model of the upper body and the biomechanical models of the human body at different ages, combined with the existing test data of volunteers, the collision analysis of the head, neck and chest was carried out to correct and verify the model, and the corrected biomechanical model of the human body was obtained. For the selected UAV products, the corresponding target finite element mesh model is established, and analysis conditions of maximum speed falling and hitting the top of the head, maximum speed horizontal impact on the forehead, and maximum speed impact on the chest are carried out. The sensor response data of the modified human biomechanical model is extracted, and the degree of human injury is evaluated according to the human injury criteria.

2. The method for generating a human biomechanical model according to claim 1, wherein: The modeling method of the geometric model of various parts of the human body is: Using image segmentation methods, the skin, bones, muscles, brain, and ligament tissues in different parts are separated to obtain segmented images; Based on the segmented image, the medical image data points are geometrically reconstructed through the threshold segmentation method. According to the shape characteristics of different parts, organs and tissues of the human body, geometric segmentation is performed against the anatomical atlas to obtain the geometric models of various parts and tissues of the human body.

3. The method for generating a human biomechanical model as claimed in claim 2, wherein: The geometric models of various parts of the human body are cleaned up until the self-intersections of the surfaces, highly refractive edges and small holes in the geometry are eliminated.

4. The method for generating a human biomechanical model according to claim 1, wherein: The specific steps to establish a hexahedral mesh model are: Import the human upper body geometry model into the Truegrid software, open the human upper body geometry model in IGES format, and obtain the point, line, and surface data of the human upper body geometry model; Define blocks according to the point, line and surface data of the human upper body geometric model until the grid is evenly distributed in the three directions of X, Y and Z, adjust the shape of the block to be consistent with the human upper body geometric model, and move the block to the position of the center of mass of the human upper body geometric model to obtain the boundary points of the block on the grid; Project the boundary points of the block on the grid to the boundary on the geometry, project the line connecting any two points in the block to the geometric boundary line, and finally project the plane surrounded by the four edges of the block onto the grid surface to obtain a hexahedral grid model.

5. The method for generating a human biomechanical model according to claim 4, wherein: The quadrilateral shell element is constructed according to the anatomical atlas, and the ligament model is obtained by combining the shell element that reflects the real geometric shape of the ligament and the simplified discrete beam element. The spring element is obtained by analyzing the muscle fiber bundles and simplifying the muscle into spring elements for modeling.

6. The method for generating a human biomechanical model according to claim 5, wherein: After the hexahedral mesh model, quadrilateral shell unit and spring unit are established, the established human head geometry model, human neck geometry model and human chest geometry model are spliced ​​based on the anatomical structure to generate a refined mesh model of the human upper body.

7. The method for generating a human biomechanical model according to claim 1, wherein: The mesh quality of the established refined mesh model of the upper body of the human body is checked. The Jacobian, warping, distortion and aspect ratio of the mesh are obtained by using the geometric integrity check method. The mesh quality evaluation index is set to determine whether there are mesh penetration and interference problems between the connected parts of the mesh and between the meshes of each part. If the mesh quality evaluation index requirements are met, it is determined that there are no mesh penetration and interference problems. The evaluation indicators of mesh quality include: for hexahedral mesh models, the number of meshes with Jacobi above 0.4 is ≥99%, the number of meshes with warpage below 40 is ≥99%, the number of meshes with distortion below 50 is ≥95%, and the number of meshes with aspect ratio below 5 is ≥95%; for quadrilateral shell elements, the number of meshes with Jacobi above 0.3 is ≥99%, the number of meshes with warpage below 40 is ≥99%, the number of meshes with distortion below 50 is ≥99%, and the number of meshes with aspect ratio below 3 is ≥99%.

8. The method for generating a human biomechanical model according to claim 1, wherein: The method for establishing the target finite element mesh model is: The upper body geometry model of the human body of other age groups other than the current age group is used as the target geometry model; a certain number of landmark points in the upper body geometry model of the human body are extracted as the reference landmark points ( x i , y i , z i ), and at the same time, the landmark points corresponding to the reference landmark points are extracted on the target geometric model as the target landmark points ( x j , y j , z j ); Assume that the number of extracted benchmark landmarks and target landmarks is n The number of all nodes in the refined mesh model of the upper body is N ; The coordinates of the transformed target geometric model are marked as ( M, P, Q ); Find the distance between two corresponding points using the Euclidean norm r Substitute the basis function and use the coordinate information of the basic geometric model to build the matrix , A is a parameter, is the transpose of P; According to the target landmark coordinate information of the target geometric model, calculate the column vector of the interpolation weight coefficient , and , the calculation formula of the nodes of the target finite element mesh model of each part is obtained as follows: ； In the formula, , , , are column vectors, is a fixed parameter; Using different interpolation weight coefficients and the column vector composed of the coordinate parameters of all nodes of the refined mesh model of the upper body of the human body, the optimal solution mapping between the benchmark landmark points and the target landmark points is performed by calculating the minimum value of the surface energy equation, and the three column vectors M, P, Q of the coordinates of the target finite element mesh model of each part after interpolation are obtained. The target finite element mesh model is constructed through the three column vectors M, P, Q.

9. The method for generating a human biomechanical model according to claim 8, wherein: Based on the upper body geometric model and the target geometric model, the reference landmarks and target landmarks are selected and marked until the positions of the reference landmarks and the target landmarks correspond and their numbers are consistent. The optimal solution mapping method is as follows: the one-to-one corresponding reference landmarks and target landmarks and the node coordinate information in the refined mesh model of the upper body are used as input conditions for mesh transformation, and all the node coordinate information of the target finite element mesh model of each part is calculated, while the unit connection remains unchanged.

10. The method for generating a human biomechanical model according to claim 1, wherein: The specific methods for model modification and verification are as follows: According to the working condition parameters of the volunteer head impact test obtained from the biomechanical research experiment of craniocerebral injury, the same analysis conditions were set for collision analysis. The accuracy of the human head geometric model was verified through the collision contact force curve, and the head test results were obtained. According to the existing volunteer trolley test condition parameters, the same analysis condition is set for collision analysis to obtain the cervical curve, and the accuracy of the human neck geometric model is verified through the cervical curve to obtain the neck test results; According to the existing volunteer chest impact test parameters, the same analysis conditions were set for collision analysis, the reliability verification of the human chest geometry model was carried out, and the chest test results were obtained; The human biomechanical model was modified and confirmed based on the test results of the head, neck and chest.

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