Bionic model for automotive occupant injury with physical signs of Chinese 50th percentile male, and its construction method and application

Abstract

The present invention discloses a bionic model for automotive occupant injury with the physical signs of the 50th percentile male in China, also known as a biomechanical model, which is a digital calculation tool in the technical field of automotive safety and intelligent high-end detection equipment. The bionic injury model of the present invention conforms to the physical sign parameters of the 50th percentile male in China in the latest human body size statistical data of the China National Institute of Standardization; the model has detailed human anatomical structure characteristics, and according to the different tissue mechanical properties, corresponding material properties are given to each organizational structure. The content of the present invention can provide basic data and technical support for product research and development in the field of intelligent high-end equipment, the integrated research of automotive active and passive safety, automotive digital evaluation technology, the research on occupant safety protection in military field explosion shocks, the research on occupant safety protection and aviation life-saving technology in the crash environment in the aerospace field, and also has broad application prospects in the fields of forensic medicine, clinical medicine and rehabilitation.

Description

Technical Field

[0001] The present invention belongs to the technical fields of human numerical calculation model development technology, automotive safety, and intelligent high-end detection equipment technology, and relates to a bionic model of automotive occupant injury with the physical signs of the 50th percentile Chinese male, as well as the key technologies and methods in its development process, and its applications in the fields of automotive crash safety, military, aerospace, research on the mechanism of human body collision injury, forensic medicine, clinical medicine, and rehabilitation fields. Background Art

[0002] The research on the mechanism of occupant injury in the field of automotive crash safety can be divided into several typical methods, such as cadaver tests, volunteer tests, Anthropometric Test Devices (ATDs), and numerical human models. Cadaver tests and volunteer tests are restricted by difficulties in sample acquisition and ethical issues, and there are few publicly available references. Nowadays, the research on human injury in vehicle collisions mainly relies on ATDs and numerical human models. In the military field, to evaluate the injury status and mechanism of personnel in the vehicle under blast shock conditions, research is mainly carried out through battlefield casualty statistics, cadaver tests based on simulated collisions, cadaver tests of real vehicle explosions, and finite element model simulations, etc. In the aerospace field, whether the aircraft structure has the ability to protect the lives of occupants under survivable crash conditions is an important indicator of the anti-crash performance of the aircraft structure. When comprehensively evaluating the anti-crash performance of the entire aircraft, standard dummy models are generally installed on the aircraft, and corresponding simulation analyses are carried out as needed.

[0003] The development of ATDs relies on various sensors to measure parameters such as force, displacement, and acceleration, so as to calculate the injury assessment indicators of various parts of the body, and use regional injury criteria to evaluate the injury risk. Therefore, the injury is not related to specific anatomical structures. ATDs are developed for specific collision directions and are divided into frontal collision and side collision dummies. Therefore, their ability to reproduce human kinematics in other collision directions is limited. There are two types of numerical human models. One is the multi-rigid body model, which can calculate the kinematic response of the human body model in a shorter CPU time. The other is the finite element human model. Compared with the above several models, the finite element human model can more accurately describe the anatomical structures of the human body, such as soft tissues like bones, internal organs, and muscles, and can effectively evaluate the human body collision response and local variables related to injury. For example, the finite element model can predict complex chest deformations and rib fractures.

[0004] The crash test dummy can be applied to the tests of impact environments related to aerospace and human life, such as the emergency escape test of aircraft occupants, the anti-crash test of helicopter seats, the launch and recovery test of manned spacecraft, the emergency landing test of transport aircraft / passenger aircraft, the parachute airdrop test, etc., and can also be used for the tests of various other dangerous impact environments, such as the motor vehicle collision safety test, the safety test of amusement facilities, the injury and protection test of the human body by explosion shock, the sports injury test, etc.

[0005] With the development of intelligent driving technology in China's automobiles, multi-posture comfortable seats have won more attention. People have shifted from simple travel needs to a greater preference for the comfort and safety of automobiles. In the military field, the number of battlefield single soldiers killed and wounded by explosions accounts for about 70% of the total casualties, and the proportion of injuries caused by explosion shock waves is as high as 60%. In the aerospace field, how to ensure the safety of pilots and passengers in a crash has become an important issue faced in the aircraft R & D process. Different countries and regions, as well as different genders and ages of drivers, result in great differences in their body sizes. Several versions of the 50th percentile male human finite element model have been developed abroad, but these human models are developed for the body sizes of Europeans and Americans. The development of the 50th percentile male finite element model in China mostly obtains it by scaling based on foreign models, which does not conform to the physiological structure characteristics of the Chinese human body. Due to the different body types of various personnel, the height, weight, body center of gravity position, moment of inertia, etc. of the human body are all different. There are certain differences between the geometric measurement sizes of the Chinese human body and the body sizes of Westerners. In real accidents, it may increase the risk of occupant injury. Therefore, based on the CT images of volunteers conforming to the physical signs of the 50th percentile Chinese male, a bionic model of the injury of automobile occupants with the physical signs of the 50th percentile Chinese male is developed to study the injury mechanism of automobile occupants with the physical signs of the 50th percentile Chinese male. Summary of the Invention

[0006] In order to solve the deficiencies existing in the prior art, the purpose of the present invention is to provide a bionic model of the injury of automobile occupants (also known as a biomechanical model) with the physical signs of the 50th percentile Chinese male, as well as the key technologies and methods in its development process, and the application scenarios of this injury bionic model.

[0007] The present invention discloses a bionic model for automotive occupant injury with the physical signs of the 50th percentile Chinese male, also known as a biomechanical model, which is a digital computing tool in the technical field of automotive safety and intelligent high-end detection equipment. The bionic injury model of the present invention conforms to the physical sign parameters of the 50th percentile Chinese male in the latest human body size statistical data of the China National Institute of Standardization; the model has detailed human anatomical structure characteristics, the solid finite element meshes in the model are mainly hexahedrons, and the 2D shell elements are mainly quadrilaterals; each organizational structure is connected in a co-node form, and different organizational structures are connected through 2D shell elements or solid elements; according to the mechanical properties of different tissues, corresponding material properties are assigned to each organizational structure. The present invention also discloses a construction method of the above-mentioned bionic model for automotive occupant injury with the physical signs of the 50th percentile Chinese male and a usage method of the model in automotive safety research. The content of the present invention can provide basic data and technical support for product research and development in the field of intelligent high-end equipment, integrated research on automotive active and passive safety, automotive digital evaluation technology, research on occupant safety protection in military field explosions and impacts, research on occupant safety protection in the crash environment in the aerospace field and aviation life-saving technology, and also has broad application prospects in forensic medicine, clinical medicine and the rehabilitation field.

[0008] The present invention proposes a construction method of a bionic model for automotive occupant injury with the physical signs of the 50th percentile Chinese male and with detailed anatomical structure. The specific steps of the construction method are as follows:

[0009] Step A: Collect CT image data of volunteers conforming to the physical signs of the 50th percentile Chinese male in multiple times, accurately extract the geometric contours of each organizational structure, reconstruct the human geometric model, and obtain the spinal geometric model; the human geometric model can be divided into a hexahedron geometric model, a polyhedron geometric model and a trapezoid geometric model according to its shape;

[0010] Step B: Correct the spinal physiological curvature of the spinal geometric model obtained in Step A according to the anatomical adult standard spinal curvature.

[0011] Step C: Perform hexahedron finite element mesh division on the hexahedron geometric model obtained in Step A; the hexahedron geometric model is a spatial shape with 8 points, 12 edges and six faces;

[0012] Step D: Perform butterfly hexahedron high-quality finite element mesh division on the polyhedron geometric model obtained in Step A to obtain a vertebral body finite element model; the number of faces of the polyhedron geometric model is greater than six;

[0013] Step E: Perform 3-in-1 hexahedron finite element mesh division on the trapezoid geometric model obtained in Step A; the lengths of the two corresponding sides of the trapezoid geometric model differ by two-thirds;

[0014] Step F: Construct the intervertebral disc, nucleus pulposus, annulus fibrosus and ligaments for the vertebral body finite element model obtained in Step D;

[0015] Step G: Adjust the finite element models obtained in Steps C, D, E and F to the occupant posture according to the comfortable sitting posture angle of the occupant;

[0016] Step H: Connect the finite element model of the automotive occupant with the physical characteristics of the 50th percentile Chinese male to finally obtain the bionic model of the automotive occupant injury of the 50th percentile Chinese male.

[0017] In the present invention, the hexahedron finite element mesh generation method for the hexahedron geometric model specifically comprises the following steps:

[0018] Step CⅠ: Import the processed hexahedron geometric model into the ANSA software in SAT format;

[0019] Step CⅡ: Set the corresponding number of meshes for each side according to the geometric model features and mesh size requirements; wherein, the number of meshes for the corresponding sides is the same;

[0020] Step CⅢ: Select any geometric surface through the "mapping" command and divide it into 2D quadrilateral shell meshes;

[0021] Step CⅣ: Based on the 2D quadrilateral shell meshes, complete the hexahedron mesh generation of the hexahedron geometric model according to the "mapping" function.

[0022] In the present invention, the high-quality finite element mesh generation method for the polyhedron geometric model specifically comprises the following steps:

[0023] Step DⅠ: Import the processed polyhedron geometric model with more than six faces into the ANSA software in SAT format;

[0024] Step DⅡ: For the polyhedron geometric model with more than six faces, to ensure high-quality finite element meshes, use butterfly mesh generation and create a "Box block" for the geometric model under the "hexahedron" module;

[0025] Step DⅢ: Divide the "Box block" at the corresponding positions of the polyhedron geometric model surface patches, and fit the corresponding points, lines and faces of the "Box block" to the corresponding points, lines and faces of the polyhedron geometric model surface patches;

[0026] Step DⅣ: Offset the points and lines on the "Box block" inward by an appropriate distance through the "butterfly mesh" command, and retain the original "Box block" to construct a butterfly region;

[0027] Step DⅤ: Set the number of meshes for the corresponding sides through the "number" instruction according to the mesh size requirements;

[0028] Step DⅥ: Apply the "pure hexahedron" command box to mesh the entire "Box block", completing the high-quality finite element mesh division of the butterfly hexahedron for the polyhedron geometric model with more than six faces.

[0029] In the present invention, the 3-in-1 hexahedron finite element mesh division method specifically includes the following steps:

[0030] Step EⅠ: Import the processed trapezoidal geometric model with the difference in the lengths of two corresponding sides being two-thirds into the ANSA software in SAT format;

[0031] Step EⅡ: For the trapezoidal geometric model with the difference in the lengths of two corresponding sides being two-thirds, to ensure high-quality finite element meshes, use the 3-in-1 hexahedron finite element mesh division method to create a "Box block" for the geometric model under the "hexahedron" module;

[0032] Step EⅢ: After splitting the "Box block" according to the surface patches of the trapezoidal geometric model, fit it to the trapezoidal geometric model;

[0033] Step EⅣ: Use the "coarse adjustment" command to offset the points and lines on the "Box block" of the short side of the trapezoidal geometric model to the long side until they are equal in length;

[0034] Step EⅤ: According to the requirements of the mesh size, set the number of meshes for the corresponding sides, select the entire "Box block" through the "pure hexahedron" command box, and perform mesh division, thus completing the hexahedron finite element mesh division of the 3-in-1 trapezoidal geometric model with the difference in the lengths of two corresponding sides being two-thirds.

[0035] In step F of the present invention, the spinal finite element mesh division method conforms to the normal physiological curvature and normal anatomical structure, and specifically includes the following steps:

[0036] Step FⅠ: Import the completed vertebral finite element mesh model into the ANSA software;

[0037] Step FⅡ: Using the lower surface of the upper vertebra as the main surface and the upper surface of the lower vertebra as the slave surface, obtain the intervertebral disc, annulus fibrosus, and nucleus pulposus structures through the "mapping" command;

[0038] Step FⅢ: On the surfaces of the inferior articular process of the upper vertebra and the superior articular process of the lower vertebra, generate a layer of 2D shell elements through the "surface mesh" command to simulate the articular cartilage;

[0039] Step FⅣ: Create a geometric surface between the inferior articular process of the upper vertebra and the superior articular process of the lower vertebra, and use the "mesh division" command to divide quadrilateral meshes for the geometric surface to simulate the articular capsule of the articular process;

[0040] Step FⅤ: Use the method in Step FⅣ to construct a quadrilateral mesh for simulating the interspinous ligament, supraspinous ligament, transverse process ligament, ligamentum flavum, anterior longitudinal ligament, and posterior longitudinal ligament, and obtain a spinal finite element model with detailed anatomical structures and conforming to the normal physiological curvature.

[0041] In Step H of the present invention, the "Topology" module, "2D Surface Mesh" module, and "3D Volume Mesh" module in ANSA software are used to connect the finite element model of a vehicle occupant with the physical characteristics of the 50th percentile male in China, and finally obtain a bionic model of vehicle occupant injury with the physical characteristics of the 50th percentile male in China.

[0042] The present invention also proposes a bionic model of vehicle occupant injury constructed based on the above method. The model conforms to the physical characteristic parameters of the 50th percentile male in the latest human body size statistical data of the China National Institute of Standardization. The model has a body weight of 67.1 kg, a sitting height of 91.7 cm, a shoulder width of 45.3 cm, 1.628 million elements, and 1.302 million nodes; the model has detailed human anatomical structure characteristics, including bones, muscles, internal organs, fat, ligaments, skin, and soft tissues; the solid finite element mesh in the model is mainly hexahedron, and the 2D shell elements are mainly quadrilateral; the various organizational structures in the model are connected in a co-node form, and different organizational structures are connected through 2D shell elements or solid elements; in this model, corresponding material properties are assigned according to the mechanical properties of each organizational structure.

[0043] Among them, the bionic model of injury can be applied to the test and evaluation of vehicle collision safety performance and the test and evaluation of occupant protection in the New Car Assessment Program; it can effectively evaluate the human body's collision response and local physical quantities related to injury, including quantitatively predicting and evaluating complex chest and abdominal deformations and fracture forms; at the same time, it can provide technical support for the research on seats, airbags, and vehicle safety performance protection during the vehicle R & D process.

[0044] Among them, the bionic model of injury has detailed anatomical structures and can realize the evaluation of fractures, craniocerebral injuries, and internal organ injuries in vehicle collision simulations; the bionic model of injury is applied to accident reconstruction, providing data support for the traffic department's accident research, accident determination, and liability division, and providing data support for forensic medicine's research on casualties in accidents;

[0045] Among them, the bionic model of injury has structural bionics and is applied to the research on the injury mechanism of shock waves and flying objects to occupants and the safety protection of occupants under explosion conditions in the military field; it provides technical support for the research on occupant safety protection and aviation rescue technology under the crash environment in the aerospace field.

[0046] Among them, the injury bionic model is applied in clinical basic research by the finite element method, including the application research on fracture forms and fixed rehabilitation brackets through the finite element method in orthopedics.

[0047] The beneficial effects of the present invention include: the construction of the bionic model of the injuries of vehicle occupants with the physical signs of the 50th percentile male in China proposed by the present invention improves the finite element model of vehicle occupants more in line with the physical signs of the 50th percentile male in China. Compared with the models of vehicle occupants with the physical signs of the 50th percentile male developed abroad and scaled in China, the anatomical characteristics are more obvious, the biological simulation degree is higher, and it can more accurately judge different stress and strain of the human body and its injury conditions;

[0048] In the present invention, a spinal column model with detailed anatomical structure and in line with the normal physiological curvature of males is constructed. The spinal column model includes vertebrae, transverse processes, spinous processes, superior and inferior articular processes, articular facet joints, anterior longitudinal ligament, posterior longitudinal ligament, ligamentum flavum, intertransverse ligament, interspinous ligament, and supraspinous ligament that are detailed and in line with the real structure; it can more accurately analyze the injury conditions of spinal column vertebrae under various working conditions and provide technical support for spinal column protection and injury research;

[0049] The different mesh generation methods proposed in the present invention for different geometric models and mesh quality requirements can obtain higher mesh quality, make the calculation results more accurate and the error tolerance higher during the simulation calculation process; the present invention can provide basic data and technical support for the integrated research on the active and passive safety of vehicles, the digital evaluation technology of vehicles, the research on the safety protection of occupants against explosion shock in the military field, the research on the safety protection of occupants in the crash environment in the aerospace field, and the aviation rescue technology research, and also has a wide application prospect in the fields of forensic medicine, clinical medicine and rehabilitation. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative efforts.

[0051] Figure 1 It is a flow chart of the construction method and application of the bionic model of the injuries of vehicle occupants with the physical signs of the 50th percentile male in China of the present invention.

[0052] Figure 2 For the adjustment of the physiological curvature of the spinal column; among them, (a) the physiological curvature of the spinal column before adjustment, (b) the physiological curvature curve of the spinal column of the 50th percentile male, (c) the physiological curvature of the spinal column after adjustment.

[0053] Figure 3Schematic diagram of hexahedron finite element mesh generation for a hexahedron geometric model; where (a) is the processed hexahedron geometric model, (b) is to set the number of meshes for the corresponding edges of the geometric model, (c) is to generate 2D quadrilateral shell meshes on one end face, and (d) is the completed hexahedron finite element mesh of the hexahedron geometric model.

[0054] Figure 4 Schematic diagram of butterfly hexahedron finite element mesh generation for a polyhedron geometric model with more than six faces; where (a) is the processed polyhedron geometric model with more than six faces, (b) is to construct a new "Box block", (c) is to divide the "Box block", (d) is to fit the "Box block", (e) is to construct a butterfly region, (f) is to set the number of meshes for each edge of the "Box block", and (g) is the completed butterfly hexahedron finite element mesh of the polyhedron geometric model with more than six faces.

[0055] Figure 5 Schematic diagram of 3-in-1 hexahedron finite element mesh generation for a trapezoid geometric model with a two-thirds difference in the lengths of two corresponding sides; where (a) is the processed trapezoid geometric model with a two-thirds difference in the lengths of two corresponding sides, (b) is to construct a new "Box block", (c) is to divide the "Box block", (d) is to fit the "Box block", (e) is to offset the short side towards the long side, (f) is to set the number of meshes for each edge of the "Box block", and (g) is the completed 3-in-1 hexahedron finite element mesh of the trapezoid geometric model with a two-thirds difference in the lengths of two corresponding sides.

[0056] Figure 6 Schematic diagram of finite element mesh generation for a spinal finite element model conforming to the normal physiological curvature; where (a) is to construct the intervertebral disc, (b) is to distinguish the nucleus pulposus and annulus fibrosus, (c) is to construct the articular process joint cartilage, (d) is to construct the geometric surface of the articular process joint capsule, (e) is to construct the 2D shell mesh of the articular process joint capsule, (f) is to construct the geometric surface of the intervertebral ligament, (g) is to construct the 2D shell mesh of the intervertebral ligament, and (h) is the completed spinal finite element model.

[0057] Figure 7 Determination of the rotation axes of various parts for occupant posture adjustment; where (a) is the rotation axis of the upper torso, (b) is the rotation axis of the lower leg, (c) is the rotation axis of the upper limb, and (d) is the rotation axis of the elbow joint.

[0058] Figure 8 Schematic diagram of muscle shape adjustment; where (a) is to construct a "Box block" for the deformed area, (b) is to divide the "Box block", (c) is the deformed finite element mesh area, (d) is to delete unqualified meshes, (e) is to construct the geometric surface of the deletion area, (f) is to construct the 2D shell mesh of the geometric surface, and (g) is to complete the hexahedron finite element mesh of the deletion area.

[0059] Figure 9 Schematic diagram of the bionic model for the injury of an automotive occupant with the physical characteristics of the 50th percentile Chinese male according to the present invention; among them, (a) front view, (b) side view.

[0060] Figure 10 Schematic diagram of the cooperation between an automotive occupant with the physical characteristics of the 50th percentile Chinese male and a seat in an embodiment of the present invention.

[0061] Figure 11 Schematic diagram of the rotation angle of the centroid of the head of an automotive occupant with the physical characteristics of the 50th percentile Chinese male in an embodiment of the present invention. Detailed implementation manners

[0062] The present invention will be further described in detail with reference to the following specific embodiments and the accompanying drawings. The processes, conditions, experimental methods, etc. for implementing the present invention, except for the specifically mentioned content below, are all common knowledge and well-known common sense in the art, and the present invention has no particularly restricted content.

[0063] The bionic model for the injury of an automotive occupant (also known as the biomechanical model) with the physical characteristics of the 50th percentile Chinese male proposed in the present invention has a body weight of 67.1 kg, a sitting height of 91.7 cm, a shoulder width of 45.3 cm, 1.628 million elements, and 1.302 million nodes; the bionic model for the injury conforms to the physical characteristic parameters of the 50th percentile Chinese male in the latest human body size statistical data of the China National Institute of Standardization. This model has detailed human anatomical structure features, including bones, muscles, internal organs, fat, ligaments, skin, and soft tissues; the solid finite element meshes in the model are mainly hexahedrons, and the 2D shell elements are mainly quadrilaterals; the various organizational structures in the model are connected in a co - node form, and different organizational structures are connected through 2D shell elements or solid elements; in this model, corresponding material properties are assigned according to the mechanical properties of each organizational structure; compared with females, the male bionic model for the injury has thicker bones, wider shoulders and narrower hips, a thicker skull, and a smaller pelvis; from the perspective of ergonomics, the 50th percentile male is quite different from the 5th percentile female and children in terms of height, weight, body shape, etc., resulting in significant differences in the center - of - gravity position, moment of inertia, rotation radius, etc. of various parts of the human body.

[0064] The injury bionic model constructs a spinal model with detailed anatomical structures that conforms to the normal physiological curvature of males. The spinal model includes vertebrae, transverse processes, spinous processes, superior and inferior articular processes, articular facet joints, anterior longitudinal ligament, posterior longitudinal ligament, ligamentum flavum, intertransverse ligament, interspinous ligament, and supraspinous ligament that are detailed and conform to the real structure; the inferior articular processes of the upper vertebrae in the cervical and thoracic vertebrae are concave, and the superior articular processes of the lower vertebrae are convex. The inferior articular processes of the upper vertebrae in the lumbar vertebrae are convex, and the superior articular processes of the lower vertebrae are concave, enabling each vertebra to rotate around the articular facet joints; the injury bionic model has a high degree of biological simulation and can be used to carry out biomechanical research on the collision of automobile occupants with the physical signs of the 50th percentile male in China.

[0065] The present invention provides a method for constructing a finite element mesh of the above injury bionic model, including the following steps:

[0066] Step A: Collect CT image data of volunteers conforming to the physical signs of the 50th percentile male in China in multiple times. According to the real structural anatomy of each tissue, accurately extract the geometric models of tissues such as bones, muscles, skin, and internal organs through Mimics software, and reconstruct the human geometric model; import it into Geomagic software in STL format, and perform smooth processing on the geometric model through functions such as sandpaper, rapid smoothing, and feature removal. At the precise surface stage, divide the surface patches according to the structural characteristics of each tissue, and import the processed geometric models of each tissue into the preprocessing software ANSA in SAT format;

[0067] Step B: For the hexahedral geometric structures of ribs, collarbones, and muscles, set the number of meshes for each side of the geometric model in the "2D surface mesh (MESH)" module in ANSA software to ensure that the length of a single finite element mesh is not less than 1.5 mm; in the "3D volume mesh (VOLUME MESH)" module, complete the hexahedral mesh division through the "Map" function to achieve the hexahedral finite element mesh division of the hexahedral geometric structures;

[0068] Among them, the hexahedron is a spatial shape with 8 points, 12 edges, and six faces; the butterfly mesh is a method of hexahedral finite element mesh division in which several layers of body meshes are added inward from the 3D body mesh on the surface of the geometric body; the geometric model surface patch is a sheet-like area on the geometric surface that contains points, lines, and faces and has a finite simply connected circular boundary; the "Box block" is a dividable hexahedral block that wraps the selected elements;

[0069] Step C: For the polyhedral geometric models of the sternum, vertebrae, scapulae, sacrum, hip bones, long bones of the extremities, and visceral organ tissue surfaces with more than six sides, use the butterfly grid. Under the "Hexablock" module in the ANSA software, create a "Box block" for the geometric model through the "Boxes" function. Cut the "Box block" according to the corresponding positions of the geometric model surface patches, and fit the corresponding points, lines, and faces of the "Box block" to the corresponding points, lines, and faces of the geometric model surface patches. Offset the "Box block" inward by 3 - 8 mm through the "O-Grid" command and retain the original "Box block". The area composed of the original "Box block" and the offset "Box block" is the butterfly grid area. Set the number of grids on each side of the original "Box block" and the offset "Box block" respectively, and perform mesh division through the "Pure Hexa" instruction to obtain a complete butterfly hexahedron finite element mesh model;

[0070] Step D: For the trapezoidal geometric model with a two-thirds difference in the lengths of two corresponding sides, to ensure high-quality finite element meshes, use the 3-in-1 mesh division method. Merge 3 finite element meshes on the short side into 1 finite element mesh, and create a "Box block" for the geometric model under the "Hexa BLOCK" module. Divide the "Box block" according to the corresponding positions of the points, lines, and faces of the geometric model surface patches, and fit the points, lines, and faces of the "Box block" to the corresponding points, lines, and faces of the geometric surface patches. Select the above "Box block" through the "Coarse" command, and offset the points and lines on the short-side "Box block" of the geometric model to the same length as the long side according to the instruction. Set the number of grids on the corresponding sides according to the mesh size requirements. Select the "Pure Hexa" command to box-select the entire "Box block" and perform mesh division to complete the 3-in-1 hexahedron mesh division;

[0071] Among them, the trapezoidal geometric model is: there is a two-thirds difference in the lengths of two corresponding sides. If the mesh division method with equal numbers of grids on two corresponding sides is used, the grids on the short side are too concentrated, resulting in unqualified mesh quality. Therefore, the 3-in-1 finite element mesh division method is used.

[0072] Step E: Based on the vertebra finite element model obtained in Step C, rotate and translate it to the physiological curvature position of the spinal anatomy through the "Transform" command. Under the "VOLUME MESH" module, select the lower surface of the upper vertebra body as the main surface and the upper surface of the lower vertebra body as the slave surface through the "Map" command, and set the number of intermediate mesh layers to 4 to obtain the intervertebral disc structure. Set the outer three layers of the intervertebral disc as the annulus fibrosus and the remaining internal structure as the nucleus pulposus to obtain the "vertebra - intervertebral disc" finite element model that conforms to the physiological curvature of the spinal anatomy;

[0073] Step F: Based on the "vertebra-disc" finite element model obtained in Step E, under the "2D Surface Mesh (MESH)" module, use the "Surface Mesh (Vol.Shell)" command to generate a layer of 2D shell elements on the surfaces of the inferior articular processes of the superior vertebra and the superior articular processes of the inferior vertebra to simulate articular cartilage; use the "Faces" function under the "TOPO" module to create a geometric surface between the inferior articular processes of the superior vertebra and the superior articular processes of the inferior vertebra, and use the "Mesh Generation" command under the "2D Surface Mesh (MESH)" module to divide quadrilateral meshes for the geometric surface to simulate the articular capsule of the articular processes; use the above method to construct quadrilateral meshes to simulate the interspinous ligament, supraspinous ligament, transverse process ligament, ligamentum flavum, anterior longitudinal ligament, and posterior longitudinal ligament, and thus obtain a spinal finite element model with detailed anatomical structures and conforming to the normal physiological curvature.

[0074] Step G: For the skin, ligament, joint capsule, pia mater, and dura mater tissue structures, divide 2D shell elements for simulation using the "Mesh Generation" command under the "2D Surface Mesh (MESH)" module.

[0075] Step H: After meshing and connecting each tissue structure, adjust the model to the occupant posture according to the comfortable angle of the trunk in the adult sitting posture; correct the muscle shape in the sitting posture of the model. The correction of the muscle shape is to optimize and adjust the muscle shape in the human body according to the stretching and compression deformation of the muscles in the normal state; in the "MORPH" module of ANSA software, select the muscles to be deformed in the "Boxes" toolbar of the "MORPH" module to create a "Box block", and use the "Split" instruction to divide the deformation area of the "Box block"; in the "Box Morphing" toolbar, use operations such as moving and rotating to move the nodes of the "Box block" to achieve the compression or stretching deformation of the muscles; for areas with large deformation resulting in poor mesh quality, delete the unqualified meshes, create a geometric surface under the "TOPO" module, and use the "Extrude" and "Solid Builder" commands under the "3D Volume Mesh (VOLUME MESH)" module to complete the muscle solid mesh to obtain the deformed muscle finite element model.

[0076] The mesh quality parameters are that the Jacobian is greater than 0.3, the warping degree is less than 50°, the distortion degree is less than 60°, the aspect ratio is less than 8, and whether there is negative volume; among them, the Jacobian is an index used to describe the shape transformation of mesh elements. For three-dimensional mesh elements, the Jacobian is a 3×3 matrix that describes the mapping transformation of mesh elements from the original coordinate space to the physical space. In mesh quality inspection, it is necessary to ensure that the value of the Jacobian is greater than or equal to zero, otherwise it indicates that there is reverse or flipping in the mesh element; the warping degree (Skewness) is an index used to measure the non-uniformity of internal angles of mesh elements. For three-dimensional mesh elements, the warping degree is usually expressed as the difference between the largest internal angle and the smallest internal angle of an angle. A larger warping degree value indicates a larger difference in internal angles of the mesh element, which may lead to unstable numerical calculations or decreased accuracy; the distortion degree (Distortion) is an index used to describe the degree of shape distortion of mesh elements. The distortion degree index can be compared according to the vertex positions of mesh elements and the ideal shape. A larger distortion degree value indicates that the shape of the mesh element is more distorted, which may affect the accuracy of the simulation results; the aspect ratio is the ratio of the lengths of the sides of the mesh element. In a two-dimensional mesh, the aspect ratio usually refers to the ratio of the length of the longest side to the length of the shortest side of the mesh element. A larger aspect ratio value indicates that the shape of the mesh element is very slender or very flat, which may lead to an increase in numerical calculation errors; the negative volume phenomenon refers to the situation where the volume of the mesh element is negative. In a three-dimensional mesh, a negative volume indicates that the face of the mesh element is facing the wrong direction or there is reverse in the mesh element. The negative volume phenomenon will lead to numerical calculation errors, so it is necessary to exclude such mesh elements in mesh quality inspection;

[0077] Step I: The head, neck, chest, abdomen and limbs of the finite element model are connected with common nodes by simulating tendons through shell elements; the generation of fat is bounded by the skin geometric model, and the "Exturde" command in ANSA software is used to project the fascia shell elements attached to the outside of the muscle onto the skin geometric surface, and three layers of hexahedral meshes are constructed between the muscle and the skin.

[0078] The bionic model of automotive occupant injury with the physical signs of the 50th percentile Chinese male proposed by the present invention assigns corresponding material properties to different tissue structures in the bionic model according to their anatomical characteristics and mesh types, and is used for simulating and calculating the injury mechanism and safety protection research of occupants with the physical signs of the 50th percentile Chinese male in the fields of automotive collision safety, military and aerospace; the model has carried out corresponding experimental verifications on its effectiveness for the head, neck, chest and abdomen, and lower limbs respectively.

[0079] The present invention proposes a research method for automotive collision injury mechanism based on the bionic model of automotive occupant injury with the physical signs of the 50th percentile Chinese male, including:

[0080] Step Ⅰ: Import the bionic model of automobile occupant injury with the physical signs of the 50th percentile Chinese male and the finite element model of a simplified seat into the ANSA software;

[0081] Step Ⅱ: Use the "Transform" tool to translate and rotate the bionic model of automobile occupant injury with the physical signs of the 50th percentile Chinese male onto the seat, ensuring that the occupant model contacts the seat without penetration and interference problems;

[0082] Step Ⅲ: In the "SeatBelt Tool" toolbar in the ANSA software, create a three-point seat belt for the bionic model of automobile occupant injury with the physical signs of the 50th percentile Chinese male according to the instructions, adjust the seat belt path to a suitable position, and assign material properties to the seat belt;

[0083] Step Ⅳ: Set surface-to-surface contacts for the bionic model of automobile occupant injury with the physical signs of the 50th percentile Chinese male, the seat belt, the seat, and the floor to ensure the transfer of force, and set a gravity field for the whole;

[0084] Step Ⅴ: Apply a velocity curve in the positive forward direction to the seat model to conduct a rear collision neck whiplash test;

[0085] Step Ⅵ: Output the corresponding kinematic and biomechanical parameters of the head and neck of the bionic model of automobile occupant injury with the physical signs of the 50th percentile Chinese male, and comprehensively evaluate the head and neck injury conditions of the bionic model of automobile occupant injury with the physical signs of the 50th percentile Chinese male.

[0086] Embodiment

[0087] Based on the CT image data of volunteers with the physical signs of the 50th percentile Chinese male, the geometric models of various tissues and organs are extracted according to the anatomical structures of each tissue in the medical software. Through reverse processing and meshing, a finite element model of the head, neck, chest, abdomen, and limbs with detailed anatomical structures of the 50th percentile Chinese male is constructed. The posture is adjusted according to the comfortable angle range of the trunk in the sitting posture of the occupant, and each tissue part is connected to develop a bionic model of automobile occupant injury with the physical signs of the 50th percentile Chinese male. Its construction method and application are as Figure 1 shown.

[0088] The reverse processing is defined as constructing a surface based on the point cloud data for subsequent structural and functional design.

[0089] The construction of the model of the present invention includes the following steps:

[0090] (1) Geometric model reconstruction method.

[0091] According to the latest measurement and statistical data of the China National Institute of Standardization, the CT scan data of male volunteers with a height of 171 cm and a weight of 67 kg were selected to construct a finite element model. The CT cross-sectional scan data of the volunteers in a lying position, who conformed to the physical signs of the 50th percentile Chinese men, were imported into the medical software Mimics in DICOM format. In the Mimics software, the bone threshold range was set to [148, 1968], the muscle to [-5, 135], and the skin to [-718, -177]. The above tissues were segmented and extracted. For the brain tissue, muscle, and internal organs that could not be directly extracted, a new layer with a threshold range of [0, 0] was established, and the geometric model was manually traced and extracted according to the anatomical structure. Finally, it was imported into the Geomagic software in STL format; under the polygon module of the Geomagic software, the extracted geometric model was smoothed through tools such as Mesh Doctor, Sandpaper, Quick Smooth, and Feature Removal. In the precise surface stage, each tissue structure was divided into surface patches according to the anatomical structure, the surface was fitted, and it was exported in SAT format.

[0092] (2) Method for adjusting the physiological curvature of the spine of automobile occupants with the physical signs of the 50th percentile Chinese men.

[0093] As Figure 2 (a) shows the physiological curvature of the spine obtained from the CT cross-sectional scan of the volunteer in a lying position. Therefore, it is necessary to adjust this spine to the physiological curvature of the spine in the normal standing position. According to the image of the normal physiological curvature of the adult spine, 3 points were evenly traced on each vertebral body and the sacrum in the sagittal plane direction in the CATIA software, and they were connected into a line with a spline curve to obtain a spine curve that conforms to the normal physiological curvature. This curve was exported in IGES format, as Figure 2 (b) shows; this curve was imported into ANSA, and through the "Transform" tool, translation and scaling were performed to scale this curve to the same size as the spine of the model, and the lower end point of this curve was made to coincide with the midpoint of the front half of the sacrum; each vertebral body was translated and rotated onto this curve, as Figure 2 (c) shows, and the adjustment of the physiological curvature of the spine of the bionic model of the physical signs of the 50th percentile Chinese men was completed.

[0094] (3) Finite element mesh generation method.

[0095] The hexahedral geometric model processed by the Geomagic software was imported into the ANSA software in SAT format for finite element mesh generation; as Figure 3 (a) shows, for the hexahedral geometric structures of the ribs, collarbones, and muscles, since they are mostly long strip-like columnar structures, the mapping method was used for mesh generation; as Figure 3As shown in (b), under the "2D Surface Mesh (MESH)" module in ANSA software, set the number of meshes on each corresponding edge of the geometric model to be equal through the "Number" command to ensure that the resulting 2D shell elements are quadrilaterals. When setting the number of meshes, ensure that the length of a single finite element mesh is not less than 1.5 mm to achieve high mesh quality and avoid excessive mesh numbers affecting the calculation efficiency; as Figure 3 As shown in (c), after setting the number of meshes, divide one end face of the hexahedron into quadrilateral 2D shell meshes through the "Mesh Generation" command; under the "3D Volume Mesh (VOLUMEMESH)" module, through the "Map" function, select the quadrilateral mesh completed above as the main face, the corresponding face as the slave face, and the adjacent face as the adjacent face, and complete the hexahedron mesh division according to the instructions, so as to realize the hexahedron finite element mesh division of the hexahedron geometric structure.

[0096] Import the polyhedron geometric model with more than six faces processed by Geomagic software into ANSA software in SAT format for finite element mesh division, as Figure 4 As shown in (a); for polyhedron geometric models with more than six faces of the sternum, vertebrae, scapula, sacrum, hip bone, long bones of the extremities, and visceral organ tissues, use butterfly meshes; as Figure 4 As shown in (b), under the "Hexablock" module in ANSA software, use the "New" command in the "Boxes" function to create a "Box block" for the geometric model; as Figure 4 As shown in (c), according to the layout positions of the points, lines, and faces of the geometric model surface patches, use the "Split" command to split the corresponding positions of the "Box block"; as Figure 4 As shown in (d), then through the "Association" function, respectively fit the points, lines, and faces obtained after splitting the "Box block" to the corresponding points, lines, and faces of the geometric model surface patches; as Figure 4 As shown in (e), use the "O-Grid" command to offset the "Box block" attached to the geometric model inward by 3 - 8 mm and retain the original "Box block". The area composed of the original "Box block" and the offset new "Box block" is the butterfly mesh area, and the internal area of the new "Box block" is the non-butterfly hexahedron mesh area; as Figure 4 As shown in (f), use the "Edges" function to set the number of meshes on each edge of the original "Box block" and the offset new "Box block" respectively, ensuring that the length of a single finite element mesh is not less than 1.5 mm. After setting the number of meshes, as Figure 4 As shown in (g), use the "Pure Hexa" instruction for mesh division to obtain a complete butterfly hexahedron finite element mesh model;

[0097] Import the trapezoidal geometric model with the lengths of two corresponding sides differing by two-thirds after being processed by Geomagic software into ANSA software in SAT format for finite element mesh generation, as shown in Figure 5 (a); To ensure high-quality finite element meshes, use the 3-in-1 mesh generation method to combine 3 finite element meshes on the short side into 1 finite element mesh; as shown in Figure 5 (b), under the "Hexablock" module, use the "New" command in the "Boxes" function to create a "Box block" for the geometric model; as shown in Figure 5 (c), according to the layout positions of the points, lines, and surfaces of the geometric model surface patches, use the "Split" command to split the corresponding positions of the "Box block"; as shown in Figure 5 (d), then use the "Association" function to respectively fit the points, lines, and surfaces obtained after splitting the "Box block" to the corresponding points, lines, and surfaces of the geometric model surface patches; as shown in Figure 5 (e), use the "Coarse" command to select the above-mentioned "Box block", and according to the instruction, offset the points and lines on the "Box block" on the short side of the geometric model towards the long side until they reach the position with the same length as the long side; as shown in Figure 5 (f), use the "Edges" function to respectively set the number of meshes on each side of the "Box block" to ensure that the length of a single finite element mesh is not less than 1.5 mm; as shown in Figure 5 (g), after setting the number of meshes, use the "Pure Hexa" instruction to perform mesh generation, that is, complete the 3-in-1 hexahedron finite element mesh generation;

[0098] Based on the vertebral body finite element mesh model after the above-mentioned adjustment of the spinal physiological curvature and finite element mesh generation, as shown in Figure 6 (a), under the "3D Volume Mesh" module, use the "Map" command to select the lower surface of the upper vertebral body as the main surface and the upper surface of the lower vertebral body as the slave surface, and set the number of intermediate mesh layers to 4 to construct the intervertebral disc structure; as shown in Figure 6 (b), use the "Set PID" command to define the outer three layers of the constructed intervertebral disc as the annulus fibrosus and the remaining internal structure as the nucleus pulposus, that is, obtain the "vertebra - intervertebral disc" finite element model that conforms to the spinal anatomical physiological curvature; as shown in Figure 6 (c), under the "2D Shell Mesh" module, use the "Vol.Shell" command to generate a layer of 2D shell elements on the surfaces of the inferior articular processes of the upper vertebra and the superior articular processes of the lower vertebra to simulate articular cartilage; as shown inFigure 6 As shown in (d), a geometric surface is created between the inferior articular process of the upper vertebra and the superior articular process of the lower vertebra through the "Faces" function under the "TOPO" module; as Figure 6 As shown in (e), a quadrilateral mesh is generated for the constructed geometric surface through the "Mesh Generation" command under the "2D Face Mesh (MESH)" module to simulate the articular capsule of the zygapophyseal joint; as Figure 6 As shown in (f), geometric surfaces are created between the spinous processes, transverse processes, and vertebral foramina of the upper and lower vertebrae respectively through the "Faces" function under the "TOPO" module; as Figure 6 As shown in (g), the above method is used to construct a quadrilateral mesh for simulating the interspinous ligament, supraspinous ligament, transverse process ligament, ligamentum flavum, anterior longitudinal ligament, and posterior longitudinal ligament, as Figure 6 As shown in (h), a finite element model of the spine with detailed anatomical structure and conforming to the normal physiological curvature is obtained;

[0099] For organizational structures such as skin, ligaments, joint capsules, pia mater, and dura mater, quadrilateral 2D shell elements are generated through the "Mesh Generation" command under the "2D Face Mesh (MESH)" module for simulation.

[0100] (4) Method for determining and adjusting the sitting posture of a bionic model of an automotive occupant injury with the physical signs of a 50th percentile Chinese male.

[0101] Referring to the comfortable angle range of the torso in the standard sitting posture of a 50th percentile male, the backrest angle is 20° - 30°, the angle between the torso and the thigh is 95° - 115°, the knee angle is 100° - 145°, and the foot angle is 87° - 110°. As Figure 7 shown, the horizontal axis of the rotation centers at the acetabular fossa, knee joint, shoulder joint, and elbow joint of the bionic model of an automotive occupant injury with the physical signs of a 50th percentile Chinese male is defined as the rotation axis; the angles of each joint of the bionic model of an automotive occupant injury with the physical signs of a 50th percentile Chinese male are adjusted within the comfortable angle range of the torso.

[0102] (5) Method for optimizing and adjusting the muscles of a bionic model of an automotive occupant injury with the physical signs of a 50th percentile Chinese male.

[0103] The correction of the muscle shape is to optimize and adjust the muscle shape in the human body according to the tensile and compressive deformation of the muscle in the normal state; as Figure 8 As shown in (a), in the "MORPH" module of the ANSA software, a "Box block" is created for the area to be deformed through the "New" command; as Figure 8 As shown in (b), the deformed area of the "Box block" is segmented through the "Split" instruction; asFigure 8 As shown in (c), the "Box block" nodes segmented through operations such as moving and rotating in the "Box Morphing" toolbar are adjusted to compress or stretch the muscle by referring to the normal stretching and deformation of the anatomical structure of the muscle. Figure 8 As shown in (d), for the areas with large deformation resulting in poor mesh quality, the unqualified meshes are deleted. Figure 8 As shown in (e), under the "TOPO" module, geometric faces are created in the deleted area through the "Faces" function. Figure 8 As shown in (f), under the "2D Face Mesh (MESH)" module, quadrilateral meshes are generated for the constructed geometric faces through the "Mesh Generation" command. Figure 8 As shown in (g), under the "3D Volume Mesh (VOLUME MESH)" module, the deleted muscle solid meshes are completed through the "Extrude" and "SolidBuilder" commands to obtain the deformed muscle finite element model.

[0104] (6) Connection of the bionic model of automobile occupant injury with the physical signs of the 50th percentile Chinese male.

[0105] The connection of the finite element model means that the head, neck, chest, abdomen and limbs are all connected by sharing nodes through simulating tendons with 2D shell elements; using the "Extrude" command in ANSA software, with the skin geometric model as the boundary, the projection of the fascia shell elements attached to the outside of the muscle onto the skin geometric surface is realized, and three layers of hexahedral meshes are constructed between the muscle and the skin to simulate fat, and a layer of 2D shell elements is generated on the surface of the constructed fat meshes through the "Vol.Shell" command to simulate the skin. As Figure 9 shown, connecting each tissue part will obtain the bionic model of automobile occupant injury with the physical signs of the 50th percentile Chinese male of the present invention.

[0106] As Figure 10 shown, placing the bionic model of automobile occupant injury with the physical signs of the 50th percentile Chinese male disclosed by the present invention on the seat, simulating the head and neck whiplash test in the rear collision of the automobile, and studying the injury mechanism of the automobile occupant with the physical signs of the 50th percentile Chinese male; as Figure 11 shown, outputting the rotation angle of the centroid of the model head in the test can be used to calculate the "Head Injury Criterion (HIC)", the 3ms synthetic acceleration, the "Brain Injury Criterion (BrIC)", etc., to evaluate the head and neck injury conditions in the rear collision of the automobile.

[0107] Translate the bionic model of the Chinese 50th percentile male's physical signs of vehicle occupant injury to the seat through the "Transform" tool, ensuring that the occupant model contacts the seat without penetration and interference problems; in the "SeatBelt Tool" toolbar of ANSA software, create a three-point seat belt for the occupant with the Chinese 50th percentile male's physical signs according to the instructions, adjust the seat belt path to a suitable position, and assign material properties to the seat belt; set surface-to-surface contacts for the bionic model of the Chinese 50th percentile male's physical signs of vehicle occupant injury, the seat belt, the seat and the floor to ensure the transmission of forces, and set a gravitational field globally; apply a velocity curve in the forward direction to the seat model to conduct a rear collision neck whiplash test; output the corresponding kinematic and biomechanical parameters of the head and neck of the bionic model of the Chinese 50th percentile male's physical signs of vehicle occupant injury, and comprehensively evaluate the head and neck injury conditions of the Chinese 50th percentile male's physical signs of vehicle occupant in a rear collision of the vehicle.

[0108] The protection scope of the present invention is not limited to the above embodiments. Without departing from the spirit and scope of the inventive concept, all changes and advantages that those skilled in the art can think of are included in the present invention, and the appended claims are used as the protection scope.

Claims

1. A method for constructing a bionic model of automotive occupant injury with the physical signs of the 50th percentile Chinese male having detailed anatomical structures, characterized in that, The specific steps of the construction method are as follows: Step A: Collect the CT image data of volunteers conforming to the physical signs of Chinese 50th percentile males in multiple times, accurately extract the geometric contours of each organizational structure, reconstruct the human geometric model, and obtain the spinal geometric model; the human geometric model can be divided into a hexahedron geometric model, a polyhedron geometric model, and a trapezoid geometric model according to its shape; Step B: Correct the spinal physiological curvature of the spinal geometric model obtained in Step A according to the anatomical adult standard spinal curvature; Step C: Perform hexahedron finite element mesh division on the hexahedron geometric model obtained in Step A; the hexahedron geometric model is a spatial shape with 8 points, 12 edges, and six faces; Step D: Perform high-quality finite element mesh division of the butterfly-shaped hexahedron on the polyhedron geometric model obtained in Step A to obtain the vertebral body finite element model; the number of faces of the polyhedron geometric model is greater than six; the specific steps of the high-quality finite element mesh division method for the polyhedron geometric model are as follows: Step DⅠ: Import the processed polyhedron geometric model with more than six faces into the ANSA software in SAT format; Step DⅡ: For the polyhedron geometric model with more than six faces, in order to ensure high-quality finite element meshes, use butterfly mesh division to create a "Box block" for the geometric model under the "Hexahedron" module; Step DⅢ: Divide the "Box block" at the corresponding position of the polyhedron geometric model surface patch, and fit the corresponding points, lines, and faces of the "Box block" to the corresponding points, lines, and faces of the polyhedron geometric model surface patch; Step DⅣ: Offset the points and lines on the "Box block" inward through the "Butterfly Mesh" command, and retain the original "Box block" to construct a butterfly-shaped area; Step DⅤ: Set the number of meshes for the corresponding edges through the "Number" instruction according to the requirements of the mesh size; Step DⅥ: Apply the "Pure Hexahedron" command box to perform mesh division on the entire "Box block" to complete the high-quality finite element mesh division of the butterfly-shaped hexahedron of the polyhedron geometric model with more than six faces; Step E: Perform 3-in-1 hexahedron finite element mesh division on the trapezoid geometric model obtained in Step A; the lengths of the two corresponding sides of the trapezoid geometric model differ by two-thirds; Step F: Construct the intervertebral disc, nucleus pulposus, annulus fibrosus, and ligaments for the vertebral body finite element model obtained in Step D; Step G: Adjust the finite element models obtained in Steps C, D, E, and F to the occupant posture according to the comfortable sitting posture angle of the occupant; Step H: Connect the finite element model of the Chinese 50th percentile male physical sign automobile occupant, and finally obtain the bionic model of the Chinese 50th percentile male physical sign automobile occupant injury.

2. The construction method according to claim 1, characterized in that, The specific steps of the hexahedron finite element mesh division method for the hexahedron geometric model are as follows: Step CⅠ: Import the processed hexahedron geometric model into the ANSA software in SAT format; Step CⅡ: Set the corresponding number of meshes for each edge according to the geometric model characteristics and mesh size requirements; among them, the number of meshes of the corresponding edges is the same; Step CⅢ: Select any geometric surface through the "Map" command and divide the 2D quadrilateral shell mesh; Step CⅣ: Based on the 2D quadrilateral shell mesh, complete the hexahedron mesh generation of the hexahedron geometric model according to the "mapping" function.

3. The construction method according to claim 1, characterized in that, The specific steps of the 3-in-1 hexahedron finite element mesh generation method are as follows: Step EⅠ: Import the processed trapezoidal geometric model with the difference in the lengths of two corresponding sides being two-thirds into the ANSA software in SAT format; Step EⅡ: For the trapezoidal geometric model with the difference in the lengths of two corresponding sides being two-thirds, to ensure high-quality finite element meshes, use the 3-in-1 hexahedron finite element mesh generation method. Create a "Box block" for the geometric model under the "Hexahedron" module; Step EⅢ: After splitting the "Box block" according to the surface patches of the trapezoidal geometric model, fit it to the trapezoidal geometric model; Step EⅣ: Use the "fine tuning" command to offset the points and lines on the "Box block" of the short side of the trapezoidal geometric model to the long side until they are equal in length; Step EⅤ: According to the requirements of the mesh size, set the number of meshes on the corresponding sides. Select the entire "Box block" through the "pure hexahedron" command to perform mesh generation, thus completing the hexahedron finite element mesh generation of the 3-in-1 trapezoidal geometric model with the difference in the lengths of two corresponding sides being two-thirds.

4. The construction method according to claim 1, characterized in that, In Step F, the spinal finite element mesh generation method conforms to the normal physiological curvature and normal anatomical structure. The specific steps are as follows: Step FⅠ: Import the completed vertebral finite element mesh model into the ANSA software; Step FⅡ: Use the upper surface of the inferior vertebra as the main surface and the lower surface of the superior vertebra as the slave surface, and obtain the intervertebral disc, annulus fibrosus, and nucleus pulposus structures through the "mapping" command; Step FⅢ: On the surfaces of the inferior articular process of the superior vertebra and the superior articular process of the inferior vertebra, generate a layer of 2D shell elements through the "surface mesh" command to simulate the articular cartilage; Step FⅣ: Create a geometric surface between the inferior articular process of the superior vertebra and the superior articular process of the inferior vertebra, and use the "mesh generation" command to divide quadrilateral meshes for the geometric surface to simulate the articular capsule of the articular process; Step FⅤ: Use the method in Step FⅣ to construct quadrilateral meshes to simulate the interspinous ligament, supraspinous ligament, transverse process ligament, ligamentum flavum, anterior longitudinal ligament, and posterior longitudinal ligament, and obtain a spinal finite element model with detailed anatomical structure and conforming to the normal physiological curvature.

5. The construction method according to claim 1, characterized in that, In Step H, use the "topology" module, "2D surface mesh" module, and "3D solid mesh" module in the ANSA software to connect the finite element model of the automotive occupant with the physical characteristics of the 50th percentile Chinese male, and finally obtain the bionic model of the automotive occupant injury with the physical characteristics of the 50th percentile Chinese male.

6. A bionic model of vehicle occupant injury with the physical signs of the 50th percentile Chinese male constructed by the method according to any one of claims 1-5, characterized in that, The model conforms to the physical sign parameters of the 50th percentile male in the latest human body size statistical data of the China National Institute of Standardization. The weight of the model is 67.1 kg, the sitting height is 91.7 cm, the shoulder width is 45.3 cm, the number of elements is 1.628 million, and the number of nodes is 1.302 million. The model has detailed human anatomical structure features, including bones, muscles, internal organs, fat, ligaments, skin, and soft tissues. The solid finite element mesh in the model is mainly hexahedron, and the 2D shell elements are mainly quadrilateral. The organizational structures in the model are all connected in a co - nodal form, and different organizational structures are connected through 2D shell elements or solid elements. In this model, corresponding material properties are assigned according to the mechanical properties of each organizational structure.

7. The bionic model of vehicle occupant injury with the physical signs of the 50th percentile Chinese male according to claim 6, characterized in that, The described injury bionic model can be applied to the test and evaluation of occupant protection in automotive crash safety performance tests and new car assessment procedures; it can effectively evaluate human crash responses and local physical quantities related to injuries, including quantitatively predicting and evaluating complex chest and abdominal deformations and fracture patterns; at the same time, it can provide technical support for the research on seats, airbags, and automotive safety performance protection during the automotive R & D process.

8. The bionic model of vehicle occupant injury with the physical signs of the 50th percentile Chinese male according to claim 6, characterized in that, The described injury bionic model has a detailed anatomical structure and can achieve the evaluation of fractures, craniocerebral injuries, and internal organ injuries in automotive crash simulations. The injury bionic model is applied to accident reconstruction, providing data support for the traffic department's research on accidents, accident determination, and liability division, and providing data support for forensic medicine's research on casualties in accidents.

9. The bionic model of vehicle occupant injury with the physical signs of the 50th percentile Chinese male according to claim 6, characterized in that, The described injury bionic model has structural bionics and is applied to the research on the injury mechanism of shock waves and flying objects to occupants and the safety protection of occupants under explosion conditions in the military field; it provides technical support for the research on occupant safety protection and aviation life - saving technology under crash environments in the aerospace field.

10. The bionic model of vehicle occupant injury with the physical signs of the 50th percentile Chinese male according to claim 6, characterized in that, The described injury bionic model is applied to clinical basic research by the finite element method, including the research on fracture patterns and the application of fixed rehabilitation brackets in orthopedics through the finite element method.

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