Impact wave induced bone injury analogue simulation method based on dynamic crack propagation

Abstract

The invention provides a shock wave induced bone injury analogue simulation method based on dynamic crack propagation, and relates to the technical field of data processing. The method comprises the following steps: establishing a bone tissue geometric model; setting material attributes of cortical bones and cancellous bones in the bone tissue geometric model; performing grid division on the bone tissue geometric model; setting explosive shock wave load and boundary conditions; determining a description equation of the bone tissue under the action of the explosive shock wave load; dynamically simulating a bone crack propagation process by using an incremental unit deletion method; extracting bone crack characteristics of the formed bone cracks; and determining the bone injury degree according to the bone crack characteristics. According to the method, the bone crack propagation process is dynamically simulated by using the incremental unit deletion method in the finite element analysis process, so that the bone injury degree is evaluated according to the formed bone cracks, the accuracy of bone injury evaluation is improved, emergency treatment and usual training can be guided, and quicker and more convenient decision support is provided for actual rescue.

Description

Technical Field

[0001] The present invention relates to the technical field of data processing, and particularly to a simulation method for blast-induced bone injury based on dynamic crack propagation. Background Art

[0002] Bone injuries such as fractures and bone cracks are one of the main injuries suffered by the human body under explosion shocks, seriously affecting the survival ability and combat ability of combat personnel. Rapid assessment of bone injuries can guide emergency treatment and peacetime training.

[0003] Currently, bone injuries are mainly evaluated through experiments. Using explosion experiments to evaluate combined injuries of the human body requires conducting live explosion experiments of simulated warheads, collecting parameters such as the power parameters and speed of air shock waves, and equivalenting the injuries of the simulated human body, and then evaluating bone injuries. Experimental evaluation has high economic costs and great implementation difficulties.

[0004] Finite element simulation technology can be used to simulate and analyze bone injuries of the human body in an explosion shock environment, which can show the physical process of human bone injuries and help analyze and discover the mechanical mechanism of bone injuries. However, current finite element analysis technology requires pre-defining the crack propagation path, which means that the crack propagation direction is artificially set and cannot truly simulate the natural development of cracks. However, the crack propagation behavior is often unpredictable under non-linear dynamic loads, and current finite element analysis technology is difficult to dynamically simulate the process of bone crack propagation, resulting in low accuracy of bone injury evaluation. Summary of the Invention

[0005] In order to solve the technical problem in the prior art that it is difficult to dynamically simulate the process of bone crack propagation, resulting in low accuracy of bone injury evaluation, the present invention provides a simulation method and system for blast-induced bone injury based on dynamic crack propagation.

[0006] The technical solutions provided by the embodiments of the present invention are as follows:

[0007] First Aspect

[0008] A simulation method for blast-induced bone injury based on dynamic crack propagation provided by an embodiment of the present invention includes:

[0009] S1: Establish a geometric model of bone tissue;

[0010] S2: Set the material properties of cortical bone and cancellous bone in the geometric model of bone tissue;

[0011] S3: Perform mesh division on the geometric model of bone tissue;

[0012] S4: Set explosion shock wave loads and boundary conditions;

[0013] S5: Determine the description equation of bone tissue under the action of blast shock wave load;

[0014] S6: Use the incremental element deletion method to dynamically simulate the process of bone crack propagation;

[0015] S7: Extract the bone crack characteristics of the formed bone cracks;

[0016] S8: Determine the degree of bone injury according to the bone crack characteristics.

[0017] Second aspect

[0018] A simulation system for blast-induced bone injury based on dynamic crack propagation provided by an embodiment of the present invention includes:

[0019] A processor;

[0020] A memory, on which computer-readable instructions are stored. When the computer-readable instructions are executed by the processor, the simulation method for blast-induced bone injury based on dynamic crack propagation as described in the first aspect is implemented.

[0021] Third aspect

[0022] A computer-readable storage medium provided by an embodiment of the present invention, on which a computer program is stored. When the program is executed by a processor, the simulation method for blast-induced bone injury based on dynamic crack propagation as described in the first aspect is implemented.

[0023] The beneficial effects brought by the technical solutions provided by the embodiments of the present invention at least include:

[0024] In the present invention, the incremental element deletion method is used in the finite element analysis process to dynamically simulate the process of bone crack propagation, and then the degree of bone injury is evaluated according to the formed bone cracks, improving the accuracy of bone injury assessment, being able to guide emergency treatment and peacetime training, and providing faster and more convenient decision-making support for actual rescue. Description of the drawings

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to these drawings.

[0026] Figure 1 It is a schematic flowchart of a simulation method for blast-induced bone injury based on dynamic crack propagation provided by an embodiment of the present invention;

[0027] Figure 2Schematic diagram of the structure of a simulation system for shock wave-induced bone injury based on dynamic crack propagation provided by an embodiment of the present invention. Detailed implementation manners

[0028] The following describes the technical solutions in the present invention with reference to the accompanying drawings.

[0029] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to represent examples, illustrations or explanations. Any embodiment or design solution described as an "example" in the present invention should not be construed as being more preferred or having more advantages than other embodiments or design solutions. Exactly speaking, the use of the word "example" is intended to present concepts in a specific way. In addition, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one of the two can be selected.

[0030] In the embodiments of the present invention, "image" and "picture" can sometimes be used interchangeably. It should be noted that when their differences are not emphasized, the meanings they express are the same. "(of)", "corresponding", and "corresponding" can sometimes be used interchangeably. It should be noted that when their differences are not emphasized, the meanings they express are the same.

[0031] In the embodiments of the present invention, sometimes subscripts such as W 1 may be written in a non-subscript form such as W1. When their differences are not emphasized, the meanings they express are the same.

[0032] To make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments.

[0033] Referring to the attached Figure 1 shows a schematic flowchart of a simulation method for shock wave-induced bone injury based on dynamic crack propagation provided by an embodiment of the present invention.

[0034] The embodiments of the present invention provide a simulation method for shock wave-induced bone injury based on dynamic crack propagation. This method can be implemented by a simulation device for shock wave-induced bone injury based on dynamic crack propagation. The simulation device for shock wave-induced bone injury based on dynamic crack propagation can be a terminal or a server. The processing flow of the simulation method for shock wave-induced bone injury based on dynamic crack propagation can include the following steps:

[0035] S1: Establish a geometric model of bone tissue.

[0036] Specifically, a geometric model of bone tissue can be established using CT scan or MRI data, or a geometric model of bone tissue can be established using 3D software such as COMSOL and Ansys.

[0037] S2: Set the material properties of cortical bone and cancellous bone in the bone tissue geometric model.

[0038] It should be noted that cortical bone is located on the outer layer of the bone and is a dense and hard bone tissue. Its main functions are to provide support, protect internal tissues, and withstand large external loads. Cancellous bone is located inside the bone and is a porous tissue, usually appearing at the ends of long bones (such as the femoral head) and the centers of flat bones (such as the vertebrae). Its main functions are to reduce the weight of the bone and absorb external impacts. Setting the material properties of cortical bone and cancellous bone is to accurately reflect the true mechanical behavior of the bone. Different parts of the bone tissue (cortical bone and cancellous bone) have significant differences in material properties. Therefore, when conducting simulations, correctly assigning different material properties to these two parts is crucial for simulating bone injuries (such as fractures and bone cracks).

[0039] S3: Mesh the bone tissue geometric model.

[0040] Optionally, triangular meshes, quadrilateral meshes, hexagonal meshes, etc. can be used for meshing.

[0041] S4: Set the explosive shock wave load and boundary conditions.

[0042] Optionally, the explosive shock wave load is specifically:

[0043]

[0044] where p m represents the explosive shock pressure, t represents time, p max represents the peak pressure generated by the explosive shock wave, τ represents the positive pressure duration of the explosive shock wave, and exp represents the exponential function with the natural constant as the base.

[0045] Optionally, the peak pressure generated by the explosive shock wave is specifically:

[0046]

[0047] where represents the scaled distance, r represents the distance from the explosion center, and w represents the explosive equivalent. Optionally, the positive pressure duration of the explosive shock wave is specifically:

[0048] τ = Br 1 / 2 w 1 / 6

[0049] where B represents the explosion environment parameter.

[0050] In the present invention, by using the time-dependent explosion shock wave curve, the variation of the explosion shock wave with time can be accurately simulated. This model can capture the characteristic that the shock wave pressure gradually decays after reaching the peak, accurately simulate the shock wave behavior in the real scenario, provide a solid foundation for further damage analysis and protection design, and greatly improve the reliability and practicality of prediction and analysis.

[0051] Optionally, the boundary conditions include: the loading force boundary condition and the contact boundary condition.

[0052] Among them, the loading force boundary condition is specifically:

[0053] σ·n i =f i

[0054] Among them, σ represents stress, and n i represents the normal vector at position i on the boundary, and f i represents the explosion shock wave load acting at position i on the boundary.

[0055] It should be noted that the loading force boundary condition directly applies the external load on the boundary of the model to ensure that the external force is transmitted to the bone tissue in the form of stress. This is very important for simulating the explosion shock wave load (such as high-intensity impact) because the explosion shock wave is an external force acting on the outer surface of the bone, with a wide acting range and strong instantaneous impact.

[0056] Among them, the contact boundary condition is specifically:

[0057] (σ + -σ - )·n i =0

[0058] Among them, σ + represents the stress component on the positive side of the contact surface, σ - represents the stress component on the negative side of the contact surface, and n i represents the normal vector at position i on the boundary.

[0059] It should be noted that there may be contact phenomena between the bone tissue and other objects (such as joints, prostheses, etc.). Under explosion or impact conditions, there may be contact or even impact between the bone and other structures. The contact boundary condition can accurately simulate the mechanical behavior on the contact surface and ensure the stress balance between the positive side and the negative side.

[0060] S5: Determine the description equation of the bone tissue under the action of the explosion shock wave load.

[0061] Optionally, the description equation specifically includes: the momentum conservation equation, the energy conservation equation, and the mass conservation equation.

[0062] Among them, the momentum conservation equation is specifically as follows:

[0063]

[0064] Among them, ρ represents the bone tissue density, v represents the velocity, t represents the time, d represents the differential operator, ▽ represents the gradient operator, σ represents the stress, and f represents the external volume force.

[0065] Among them, the energy conservation equation is specifically as follows:

[0066]

[0067] Among them, e represents the internal energy, σ ij represents the stress tensor component, represents the stress component in the i-th direction (i.e., the direction of the force action) acting on the plane perpendicular to the j-th direction, v i represents the velocity in the i-th direction, x i represents the displacement in the i-th direction, represents the partial derivative operator, q represents the thermal energy, and r represents the energy radiation generated by the explosion.

[0068] Among them, the mass conservation equation is specifically as follows:

[0069]

[0070] Among them, ρ represents the bone tissue density, t represents the time, d represents the differential operator, ▽ represents the gradient operator, and v represents the velocity.

[0071] S6: Use the incremental element deletion method to dynamically simulate the process of bone crack propagation.

[0072] Among them, the incremental element deletion method (Incremental Element Deletion, IED) is a numerical method used to simulate material damage, crack propagation, and fracture in finite element analysis (Finite Element Analysis, FEA). This method dynamically simulates the generation and propagation process of cracks by gradually deleting the mesh elements whose stress or strain exceeds the failure criterion, and is particularly suitable for damage simulation of complex structures (such as bones).

[0073] In a possible implementation manner, the present invention proposes a brand-new incremental element deletion method. S6 specifically includes sub-steps S601 to S606:

[0074] S601: Define the tensile failure strain and compressive failure strain of the bone tissue.

[0075] S602: Calculate the ratio of the first principal strain of the mesh element to the tensile failure strain to obtain the first variable:

[0076]

[0077] Among them, F 1 represents the first variable, and ε 1 represents the first principal strain, and ε c represents the tensile failure strain.

[0078] S603: Calculate the ratio of the third principal strain of the grid element to the compressive failure strain to obtain the second variable:

[0079]

[0080] Among them, F 2 represents the second variable, and ε 3 represents the third principal strain, and ε t represents the compressive failure strain.

[0081] It should be noted that in three-dimensional space, the strain of a material can be represented by a symmetric matrix called the strain tensor. By performing eigenvalue decomposition on this matrix, we can obtain three eigenvalues, which are called principal strains and represent the maximum and minimum deformation amounts in different directions respectively. The first principal strain is usually the largest eigenvalue, corresponding to the maximum tensile strain of the material along a certain direction. This represents the degree to which the material stretches or expands the most in this direction. The third principal strain is usually the smallest eigenvalue (which may be negative), corresponding to the maximum compressive strain of the material along a certain direction. This represents the degree to which the material compresses or shrinks the most in this direction.

[0082] S604: Control the degradation of the Young's modulus of the grid element according to the changes of the first variable and the second variable.

[0083] In a possible implementation manner, S604 specifically includes: when 0 ≤ F 1 < 1, 0 ≤ F 2 < 1, the Young's modulus of the grid element remains 100%. At this time, it indicates that the strain inside the element has not reached the failure strain threshold of the material, so the element still maintains its original mechanical properties. At this time, keeping the Young's modulus at 100% can ensure that the mechanical behavior of the material is not affected by damage and the integrity of the material can be maintained during the simulation process. When F 1 ≥ 1 or F 2 ≥ 1, the Young's modulus of the grid element degrades to 5%. At this time, it means that the strain in the element exceeds the failure threshold and the material enters the failure state. Therefore, degrading the Young's modulus to 5% simulates the behavior of the material after failure. This can effectively reflect the weakening process of the element after failure and avoid the unreasonable load-bearing capacity of the material after failure.

[0084] In the present invention, when the strain within the element exceeds the failure threshold, the Young's modulus is rapidly degraded to 5%, which can effectively simulate the damage and failure behavior of the material and more realistically reflect the non-linear damage process of the material.

[0085] In a possible implementation, S604 is specifically: determining the Young's modulus of the grid element after degradation according to the changes of the first variable and the second variable:

[0086] E a =E 0 [1 - α 1 min(F 1 , 1) - α 2 min(F 2 , 1)]

[0087] Wherein, E a represents the Young's modulus of the grid element after degradation, E 0 represents the initial Young's modulus, α 1 represents the tensile failure coefficient, and α 2 represents the compressive failure coefficient.

[0088] Wherein, those skilled in the art can set the magnitudes of the tensile failure coefficient and the compressive failure coefficient according to the actual situation, and the present invention does not make any limitations.

[0089] In the present invention, the Young's modulus of the material gradually degrades according to the changes of the first variable and the second variable, rather than instantaneous failure. The progressive degradation model can more accurately simulate the damage accumulation process of materials such as bone tissue under different stress and strain states, avoiding the computational instability caused by the sudden loss of element stiffness. Gradually controlling the degradation of the Young's modulus of the grid element can accurately simulate the damage accumulation and crack propagation process of bone tissue. Its advantages lie in improving the simulation accuracy, enhancing the simulation stability, reducing the consumption of computing resources, and adapting to different material properties and complex loading conditions.

[0090] S605: When the degradation of the Young's modulus of the grid element reaches the degradation threshold, the grid element is deleted as a failed element.

[0091] Wherein, those skilled in the art can set the magnitude of the degradation threshold according to the actual situation, and the present invention does not make any limitations.

[0092] S606: The crack propagates along the failed element to dynamically simulate the bone crack propagation process.

[0093] In the present invention, by gradually deleting the failed elements, the gradual crack propagation process can be more realistically simulated, rather than instantaneous cracking or overall rupture. The crack path and propagation speed can be dynamically updated according to the local mechanical properties of the material, demonstrating the natural propagation law of bone cracks and improving the accuracy of bone damage assessment.

[0094] S7: Extract the bone crack characteristics of the formed bone crack.

[0095] Optionally, the bone crack characteristics include: crack length, crack propagation rate, stress intensity factor, and energy release rate.

[0096] It should be noted that the crack length refers to the physical length of the crack in the bone tissue, from the starting point to the ending point of the crack. It is a physical quantity directly measuring the scale of the bone crack. As the crack length increases, the local stress concentration phenomenon in the bone will intensify, which will lead to a decrease in the bone's load-bearing capacity.

[0097] Optionally, the stress intensity factor is specifically:

[0098]

[0099] Among them, K represents the stress intensity factor, γ represents the bone shape coefficient, σ represents the stress, and L represents the crack length.

[0100] It should be noted that the stress intensity factor is a parameter measuring the stress concentration degree at the crack tip, representing the stress intensity distribution near the crack tip. The stress intensity factor describes the stress concentration degree at the crack tip. The greater the stress at the crack tip, the easier it is to cause crack propagation or further fracture.

[0101] Optionally, the energy release rate is specifically:

[0102]

[0103] Among them, G represents the energy release rate, and E represents the elastic modulus of the bone material.

[0104] It should be noted that the energy release rate represents the elastic strain energy released per unit crack propagation length during the crack propagation process. The greater the energy release rate, the more energy is released during the crack propagation process, and the stronger the driving force for crack propagation. A higher energy release rate indicates that the crack propagation process is very active, increasing the risk of fracture.

[0105] Optionally, the crack propagation rate is specifically:

[0106] V = a(ΔK) b

[0107] Among them, V represents the crack propagation rate, ΔK represents the change value of the stress intensity factor, and a, b represent constants related to the bone material.

[0108] It should be noted that the crack growth rate is the rate at which the crack length increases with time, representing the rate of crack propagation over a period of time. The crack growth rate indicates the rate of deterioration of bone damage. The greater the crack growth rate, the more rapidly the crack propagates under a specific stress state of the bone, increasing the risk of fracture.

[0109] S8: Determine the degree of bone damage based on the characteristics of bone cracks.

[0110] In a possible implementation, S8 specifically includes sub-steps S801 and S802:

[0111] S801: Calculate the bone damage index based on the characteristics of bone cracks:

[0112] μ = λ 1 L + λ 2 V + λ 3 K + λ 4 G

[0113] where μ represents the bone damage index, L represents the crack length, V represents the crack growth rate, K represents the stress intensity factor, G represents the energy release rate, and λ 1 represents the weight coefficient of the crack length, λ 2 represents the weight coefficient of the crack growth rate, λ 3 represents the weight coefficient of the stress intensity factor, λ 4 represents the weight coefficient of the energy release rate.

[0114] Among them, those skilled in the art can set the weight coefficient λ of the crack length 1 , the weight coefficient λ of the crack growth rate 2 , the weight coefficient λ of the stress intensity factor 3 and the weight coefficient λ of the energy release rate 4 according to the actual situation, and the present invention does not make any limitations.

[0115] In the present invention, the four characteristics of crack length, growth rate, stress intensity factor, and energy release rate each represent different aspects of bone crack damage. By integrating these factors into one damage index, the degree of bone damage can be more comprehensively quantified, avoiding the limitations that may be brought by relying solely on a single index. It helps to accurately judge the severity of the damage and the risk of crack propagation, while simplifying the complex evaluation process. Ultimately, it can provide strong support for treatment decisions and improve the effectiveness of fracture prevention and treatment.

[0116] S802: Determine the degree of bone damage based on the bone damage index:

[0117] When μ < μ 1 , determine that the degree of bone damage is grade I mild damage.

[0118] When μ 1 ≤ μ < μ 2 , the degree of bone injury is determined to be grade II moderate injury.

[0119] When μ 2 ≤ μ < μ 3 , the degree of bone injury is determined to be grade III severe injury.

[0120] When μ ≥ μ 3 , the degree of bone injury is determined to be grade IV extremely severe injury.

[0121] Among them, μ 1 represents the first bone injury index threshold, μ 2 represents the second bone injury index threshold, μ 3 represents the third bone injury index threshold.

[0122] Among them, those skilled in the art can set the magnitudes of the first bone injury index threshold μ 1 , the second bone injury index threshold μ 2 and the third bone injury index threshold μ 3 according to the actual situation, and the present invention does not make any limitations.

[0123] In the present invention, by corresponding the bone injury index with different thresholds to divide the four grades of bone injury, it can not only simplify the process of injury assessment, provide a more standardized diagnostic method, but also provide an important reference basis for personalized treatment and prognosis. This grading system brings obvious benefits to fracture prevention, treatment decision-making, risk management, and patient communication, and at the same time improves the accuracy and efficiency of clinical assessment.

[0124] The beneficial effects brought by the technical solution provided by the embodiment of the present invention at least include:

[0125] In the present invention, during the finite element analysis process, the incremental element deletion method is used to dynamically simulate the bone crack propagation process, and then the degree of bone injury is evaluated according to the formed bone cracks, improving the accuracy of bone injury assessment, being able to guide emergency treatment and usual training, and providing faster and more convenient decision-making support for actual rescue.

[0126] Referring to the attached Figure 2 illustrates the structural schematic diagram of a shock wave-induced bone injury simulation system based on dynamic crack propagation provided by the present invention.

[0127] The present invention also provides a shock wave-induced bone injury simulation system 20 based on dynamic crack propagation, which is applied to the above-mentioned shock wave-induced bone injury simulation method based on dynamic crack propagation, and includes:

[0128] A processor 201.

[0129] A memory 202 stores computer-readable instructions thereon. When the computer-readable instructions are executed by a processor 201, a simulation method for shock wave-induced bone injury based on dynamic crack propagation as in the method embodiment is implemented.

[0130] The simulation system 20 for shock wave-induced bone injury based on dynamic crack propagation provided by the present invention can execute the above-mentioned simulation method for shock wave-induced bone injury based on dynamic crack propagation and achieve the same or similar technical effects. To avoid repetition, the present invention will not be described in detail.

[0131] The beneficial effects brought by the technical solution provided by the embodiments of the present invention at least include:

[0132] In the present invention, the incremental element deletion method is used in the finite element analysis process to dynamically simulate the bone crack propagation process, and then the bone injury degree is evaluated according to the formed bone cracks, improving the accuracy of bone injury evaluation, being able to guide emergency treatment and normal training, and providing faster and more convenient decision-making support for actual rescue.

[0133] It should be understood that the processor in the embodiments of the present invention may be a central processing unit (CPU), and the processor may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0134] It should also be understood that the memory in the embodiments of the present invention may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example but not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchlink DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0135] The above embodiments can be implemented in whole or in part by software, hardware (such as circuits), firmware, or any combination thereof. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the processes or functions described in the embodiments of the present invention are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wired (such as infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or a data center that contains one or more collections of available media. The available media can be magnetic media (such as floppy disks, hard disks, magnetic tapes), optical media (such as DVDs), or semiconductor media. The semiconductor media can be a solid-state drive.

[0136] It should be understood that the term "and / or" in this document is merely a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Here, A and B can be singular or plural. In addition, the character " / " in this document generally represents an "or" relationship between the associated objects before and after, but it may also represent an "and / or" relationship, which can be specifically understood with reference to the context.

[0137] In the present invention, "at least one" means one or more, and "a plurality" means two or more. "At least one of the following" or its similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c can represent: a, b, c, a - b, a - c, b - c, or a - b - c, where a, b, and c can be single or multiple.

[0138] It should be understood that in various embodiments of the present invention, the magnitudes of the sequence numbers of the above processes do not mean the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

[0139] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Skilled professionals can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0140] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the above-described devices, apparatuses, and units can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0141] In several embodiments provided by the present invention, it should be understood that the disclosed devices, apparatuses, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be electrical, mechanical, or other forms.

[0142] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place, or they can be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0143] In addition, the functional units in various embodiments of the present invention can be integrated in one processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit.

[0144] When the above-mentioned function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical discs that can store program codes.

[0145] An embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, it implements the simulation method for shock wave-induced bone injury based on dynamic crack propagation as described in the method embodiment.

[0146] The computer-readable storage medium provided by the present invention can implement the steps and effects of the simulation method for shock wave-induced bone injury based on dynamic crack propagation in the above method embodiment. To avoid repetition, the present invention will not elaborate further.

[0147] The beneficial effects brought by the technical solution provided by the embodiments of the present invention at least include:

[0148] In the present invention, during the finite element analysis process, the incremental element deletion method is used to dynamically simulate the bone crack propagation process, and then the bone injury degree is evaluated according to the formed bone cracks, improving the accuracy of bone injury assessment, being able to guide emergency treatment and usual training, and providing faster and more convenient decision-making support for actual rescue.

[0149] As described above, the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

[0150] The following points need to be explained:

[0151] (1) The drawings of the embodiments of the present invention only relate to the structures involved in the embodiments of the present invention, and other structures can refer to the usual designs.

[0152] (2) For clarity, in the drawings used to describe the embodiments of the present invention, the thickness of layers or regions is enlarged or reduced, that is, these drawings are not drawn to actual scale. It can be understood that when an element such as a layer, film, region or substrate is referred to as being "on" or "under" another element, the element can be "directly" on or under the other element or there can be intervening elements.

[0153] (3) Without conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to obtain new embodiments.

[0154] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. The protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for simulating bone damage caused by shock waves based on dynamic crack propagation, characterized in that: include: S1: Establish bone tissue geometric model; S2: setting material properties of cortical bone and cancellous bone in the bone tissue geometric model; S3: Meshing the bone tissue geometric model; S4: Set explosion shock wave load and boundary conditions; S5: Determine the descriptive equation of bone tissue under the action of blast shock wave load; S6: Dynamically simulate the bone crack propagation process using the incremental element deletion method; S7: extracting bone crack features of the formed bone cracks; S8: Determine the extent of bone damage based on the bone crack characteristics.

2. The method for simulating bone damage caused by shock waves based on dynamic crack extension according to claim 1, characterized in that: The boundary conditions include: loading force boundary conditions and contact boundary conditions.

3. The method for simulating bone damage caused by shock waves based on dynamic crack propagation according to claim 1, characterized in that: The descriptive equations specifically include: momentum conservation equation, energy conservation equation and mass conservation equation.

4. The method for simulating bone damage caused by shock waves based on dynamic crack propagation according to claim 1, characterized in that: The S6 specifically includes: S601: Define the tensile failure strain and compressive failure strain of bone tissue; S602: Calculate the ratio of the first principal strain of the grid unit to the tensile failure strain to obtain a first variable: Among them, F1 represents the first variable, ε1 represents the first principal strain, ε c represents the tensile failure strain; S603: Calculate the ratio of the third principal strain of the grid unit to the compressive failure strain to obtain a second variable: Among them, F2 represents the second variable, ε3 represents the third principal strain, and ε t represents the compressive failure strain; S604: Controlling the degradation of the Young's modulus of the grid unit according to the changes of the first variable and the second variable; S605: When the degradation of the Young's modulus of the mesh unit reaches a degradation threshold, the mesh unit is deleted as a failed unit; S606: The crack propagates along the failed element to dynamically simulate the bone crack propagation process.

5. The method for simulating bone damage caused by shock waves based on dynamic crack propagation according to claim 4, characterized in that: The S604 specifically includes: When 0≤F1<1,0≤F2<1, the Young's modulus of the grid unit remains 100%; When F1≥1 or F2≥1, the Young's modulus of the mesh element degenerates to 5%.

6. The method for simulating bone damage caused by shock waves based on dynamic crack extension according to claim 4, characterized in that: The S604 is specifically as follows: According to the changes of the first variable and the second variable, the Young's modulus of the degraded grid unit is determined: Yes a =E0[1-α1min(F1,1)-α2min(F2,1)] Among them, E a It represents the Young's modulus of the mesh unit after degradation, E0 represents the initial Young's modulus, α1 represents the tensile failure coefficient, and α2 represents the compressive failure coefficient.

7. The method for simulating bone damage caused by shock waves based on dynamic crack extension according to claim 1, characterized in that: The bone crack characteristics include: crack length, crack growth rate, stress intensity factor and energy release rate.

8. The method for simulating bone damage caused by shock waves based on dynamic crack extension according to claim 7, characterized in that: The stress intensity factor is specifically: Among them, K represents stress intensity factor, γ represents bone shape factor, σ represents stress, and L represents crack length; The energy release rate is specifically: Among them, G represents the energy release rate, and E represents the elastic modulus of the bone material; The crack growth rate is specifically: V=a(ΔK) b Where V represents the crack growth rate, ΔK represents the change in stress intensity factor, and a and b represent constants related to bone materials.

9. The method for simulating bone damage caused by shock waves based on dynamic crack propagation according to claim 8, characterized in that: The S8 specifically includes: S801: Calculate the bone injury index according to the bone crack characteristics: μ=λ1L+λ2V+λ3K+λ4G Wherein, μ represents the bone damage index, L represents the crack length, V represents the crack growth rate, K represents the stress intensity factor, G represents the energy release rate, λ1 represents the weight coefficient of the crack length, λ2 represents the weight coefficient of the crack growth rate, λ3 represents the weight coefficient of the stress intensity factor, and λ4 represents the weight coefficient of the energy release rate; S802: Determine the degree of bone damage according to the bone damage index: When μ<μ1, the degree of bone injury is determined to be grade I mild injury; When μ1≤μ<μ2, the degree of bone injury is determined to be grade II moderate injury; When μ2≤μ<μ3, the degree of bone injury is determined to be grade III severe injury; When μ≥μ3, the degree of bone injury is determined to be grade IV extremely severe injury; Among them, μ1 represents the first bone injury index threshold, μ2 represents the second bone injury index threshold, and μ3 represents the third bone injury index threshold.

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