A simulation method for shock wave-induced bone damage based on dynamic crack propagation

Abstract

The present invention provides a simulation method for shock wave-induced bone damage based on dynamic crack expansion, which relates to the field of data processing technology. The method includes: establishing a bone tissue geometric model; setting the material properties of cortical bone and cancellous bone in the bone tissue geometric model; meshing the bone tissue geometric model; setting the explosion shock wave load and boundary conditions; determining the description equation of the bone tissue under the action of the explosion shock wave load; using the incremental unit deletion method to dynamically simulate the bone crack expansion process; extracting the bone crack characteristics of the formed bone cracks; and determining the degree of bone damage based on the bone crack characteristics. The present invention uses the incremental unit deletion method to dynamically simulate the bone crack expansion process during the finite element analysis process, and then evaluates the degree of bone damage based on the formed bone cracks, thereby improving the accuracy of bone damage assessment, being able to guide emergency treatment and routine training, and providing faster and more convenient decision support for actual rescue.

Description

Technical Field

[0001] The present invention relates to the technical field of data processing, and in particular to a simulation method for shock wave-induced bone damage based on dynamic crack expansion. Background Art

[0002] Bone injuries such as fractures and cracks are one of the main injuries suffered by the human body under the impact of explosions, which seriously affect the survivability and combat capability of combatants. Rapid assessment of bone injuries can guide emergency treatment and routine training.

[0003] Currently, bone injury assessment is primarily conducted through testing. Using explosion tests to assess complex injuries in humans requires conducting simulated warhead explosions, collecting parameters such as the power and velocity of the air shock wave, and then performing equivalent damage tests on simulated human subjects to assess bone damage. Experimental assessments are costly and difficult to implement.

[0004] Finite element simulation technology can be used to simulate and analyze human bone damage in explosive impact environments. It can demonstrate the physical process of human bone damage and help analyze and discover the mechanical mechanisms of bone damage. However, current finite element analysis technology requires the pre-defined crack propagation path, which means that the direction of crack propagation is artificially set and cannot truly simulate the natural development of cracks. However, crack propagation behavior is often unpredictable under nonlinear dynamic loads. Current finite element analysis technology has difficulty dynamically simulating the bone crack propagation process, resulting in low accuracy in bone damage assessment. Summary of the Invention

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

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

[0007] First aspect

[0008] An embodiment of the present invention provides a method for simulating shock wave-induced bone damage based on dynamic crack propagation, comprising:

[0009] S1: Establish bone tissue geometric model;

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

[0011] S3: Meshing the bone tissue geometric model;

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

[0013] S5: Determine the descriptive equation for bone tissue under blast wave loading;

[0014] S6: Dynamically simulate the bone crack propagation process using the incremental element deletion method;

[0015] S7: extracting bone crack features of the formed bone crack;

[0016] S8: Determine the extent of bone damage based on the bone crack characteristics.

[0017] Second aspect

[0018] An embodiment of the present invention provides a shock wave-induced bone damage simulation system based on dynamic crack propagation, comprising:

[0019] processor;

[0020] A memory having computer-readable instructions stored thereon, wherein when the computer-readable instructions are executed by the processor, the method for simulating bone damage induced by shock waves based on dynamic crack propagation as described in the first aspect is implemented.

[0021] The third aspect

[0022] An embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, the method for simulating shock wave-induced bone damage based on dynamic crack propagation as described in the first aspect is implemented.

[0023] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include at least:

[0024] In the present invention, the incremental unit deletion method is used in the finite element analysis process to dynamically simulate the bone crack expansion process, and then the degree of bone damage is evaluated based on the formed bone cracks, thereby improving the accuracy of bone damage assessment, guiding emergency treatment and routine training, and providing faster and more convenient decision-making support for actual rescue. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 A schematic flow chart of a method for simulating bone damage induced by shock waves based on dynamic crack propagation provided by an embodiment of the present invention;

[0027] Figure 2A schematic structural diagram of a shock wave-induced bone damage simulation system based on dynamic crack propagation provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0029] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as an "exemplary" in the present invention should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of the word "exemplary" is intended to present concepts in a concrete manner. Furthermore, in the embodiments of the present invention, "and / or" can mean both or either of the two.

[0030] In the embodiments of the present invention, the terms "image" and "picture" may be used interchangeably. It should be noted that, when the distinction between them is not emphasized, their intended meanings are the same. The terms "of," "corresponding," and "corresponding" may be used interchangeably. It should be noted that, when the distinction between them is not emphasized, their intended meanings are the same.

[0031] In the embodiments of the present invention, sometimes a subscript such as W1 may be written as a non-subscript such as W1. When the difference is not emphasized, the meanings to be expressed are the same.

[0032] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0033] Reference Manual Figure 1 , which shows a flow chart of a method for simulating shock wave-induced bone damage based on dynamic crack propagation provided by an embodiment of the present invention.

[0034] An embodiment of the present invention provides a method for simulating bone damage caused by shock waves based on dynamic crack propagation. The method can be implemented by a device for simulating bone damage caused by shock waves based on dynamic crack propagation. The device can be a terminal or a server. The processing flow of the method for simulating bone damage caused by shock waves based on dynamic crack propagation can include the following steps:

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

[0036] Specifically, the bone tissue geometric model can be established using CT scan or MRI data, or using three-dimensional software such as COMSOL and Ansys.

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

[0038] It should be noted that cortical bone is located in the outer layer of the skeleton and is a dense and hard bone tissue. Its main function is to provide support, protect internal tissues, and withstand large external loads. Cancellous bone is located inside the skeleton and is a loose and porous tissue. It usually appears at the ends of long bones (such as the femoral head) and the center of flat bones (such as the spine). Its main function is to reduce the weight of the bones and absorb external impacts. The material properties of cortical bone and cancellous bone are set to accurately reflect the real mechanical behavior of the bones. Different parts of bone tissue (cortical bone and cancellous bone) have significant differences in material properties. Therefore, when performing 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 geometry model.

[0040] Optionally, the grid division may be performed in the form of a triangular grid, a quadrilateral grid, a hexagonal grid, or the like.

[0041] S4: Set explosion shock wave loads and boundary conditions.

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

[0043]

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

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

[0046]

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

[0048] τ=Br 1 / 2 w 1 / 6

[0049] Wherein, B represents the explosion environment parameter.

[0050] In this paper, the temporal evolution of an explosion shock wave can be accurately simulated by using a time-dependent explosion shock wave curve. This model captures the characteristic of the shock wave pressure gradually decaying after reaching its peak, accurately simulating the shock wave behavior in real-world scenarios. This provides a solid foundation for further damage analysis and protective design, greatly improving the reliability and practicality of predictions and analysis.

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

[0052] The loading force boundary conditions are as follows:

[0053] σ·n i =f i

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

[0055] It's important to note that the force boundary condition applies external loads directly to the model's boundaries, ensuring that the external force is transmitted to the bone tissue in the form of stress. This is crucial for simulating blast wave loads (such as high-intensity impacts), as blast waves act on the outer surface of bone, exerting a wide range and delivering a strong, instantaneous impact.

[0056] The contact boundary conditions are as follows:

[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, n i Represents the normal vector at position i on the boundary.

[0059] It should be noted that bone tissue may come into contact with other objects (such as joints and prostheses). Under explosion or impact conditions, bone and other structures may come into contact or even collide with each other. Contact boundary conditions accurately simulate the mechanical behavior of the contact surface and ensure stress balance between the positive and negative sides.

[0060] S5: Determine the descriptive equations for bone tissue under blast wave loading.

[0061] Optionally, the descriptive equations specifically include: a momentum conservation equation, an energy conservation equation, and a mass conservation equation.

[0062] The momentum conservation equation is:

[0063]

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

[0065] The energy conservation equation is:

[0066]

[0067] Where e represents internal energy, σ ij Represents the stress tensor component, which means that the stress component in the i-th direction (i.e., the direction of force) acts 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 thermal energy, and r represents the energy radiation produced by the explosion.

[0068] The mass conservation equation is:

[0069]

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

[0071] S6: Dynamically simulate the bone crack propagation process using the incremental element deletion method.

[0072] Incremental Element Deletion (IED) is a numerical method used in finite element analysis (FEA) to simulate material damage, crack growth, and fracture. This method dynamically simulates crack initiation and growth by gradually deleting mesh elements whose stress or strain exceeds the failure criteria. It is particularly suitable for damage simulation of complex structures such as bone.

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

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

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

[0076]

[0077] Among them, F1 represents the first variable, ε1 represents the first principal strain, 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, F2 represents the second variable, ε3 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 deformations along different directions. The first principal strain is usually the largest eigenvalue and corresponds to the maximum tensile strain of the material along a certain direction. This represents the degree to which the material is stretched or expanded the most in that direction. The third principal strain is usually the smallest eigenvalue (which may be a negative value) and corresponds to the maximum compressive strain of the material along a certain direction. This represents the degree to which the material is compressed or contracted the most in that direction.

[0082] S604: Controlling the degradation of the Young's modulus of the mesh unit according to the changes of the first variable and the second variable.

[0083] In one possible embodiment, S604 specifically includes: when 0≤F1<1, 0≤F2<1, the Young's modulus of the grid unit remains at 100%. This indicates that the strain inside the unit has not reached the failure strain threshold of the material, so the unit still maintains its original mechanical properties. At this time, maintaining 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 F1≥1 or F2≥1, the Young's modulus of the grid unit degenerates to 5%. This indicates that the strain in the unit exceeds the failure threshold and the material enters a state of destruction. 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 unit after destruction and avoid the material still having unreasonable bearing capacity after failure.

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

[0085] In a possible implementation, S604 specifically includes determining the Young's modulus of the degraded grid unit according to changes in the first variable and the second variable:

[0086] E a =E0[1-α1min(F1,1)-α2min(F2,1)]

[0087] Among them, E a represents the Young's modulus of the mesh element after degradation, E0 represents the initial Young's modulus, α1 represents the tensile failure coefficient, and α2 represents the compressive failure coefficient.

[0088] Among them, those skilled in the art can set the magnitude of the tensile failure coefficient and the compressive failure coefficient according to actual conditions, and the present invention does not limit this.

[0089] In the present invention, the Young's modulus of the material gradually degrades based on the changes in the first and second variables, rather than instantaneously failing. This 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 unit stiffness. Gradually controlling the degradation of the Young's modulus of the mesh elements can accurately simulate the damage accumulation and crack propagation process of bone tissue. Its advantages include improved simulation accuracy, enhanced simulation stability, reduced computational resource consumption, and adaptability to different material properties and complex loading conditions.

[0090] 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.

[0091] Among them, those skilled in the art can set the degradation threshold value according to actual conditions, and the present invention does not limit it.

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

[0093] By gradually deleting failed elements, this method more realistically simulates the gradual propagation of cracks, rather than instantaneous cracking or complete rupture. The crack path and propagation rate can be dynamically updated based on the local mechanical properties of the material, demonstrating the natural propagation patterns of bone cracks and improving the accuracy of bone damage assessment.

[0094] S7: Extracting bone crack features of the formed bone crack.

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

[0096] It's important to note that crack length refers to the physical length of a crack in bone tissue, from its starting point to its end point. It directly measures the size of a bone crack. As crack length increases, localized stress concentration in the bone intensifies, leading to a decrease in the bone's load-bearing capacity.

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

[0098]

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

[0100] It should be noted that the stress intensity factor (SIF) is a parameter that measures the degree of stress concentration at the crack tip and represents the stress intensity distribution near the crack tip. The SIF describes the degree of stress concentration at the crack tip; greater stress at the crack tip increases the likelihood of crack propagation or further fracture.

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

[0102]

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

[0104] It should be noted that the energy release rate represents the amount of elastic strain energy released per unit crack extension length during crack growth. A higher energy release rate indicates more energy released during crack growth and a stronger driving force for crack growth. A higher energy release rate indicates a more active crack growth process and an increased risk of fracture.

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

[0106] V=a(ΔK) b

[0107] 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.

[0108] It's important to note that the crack growth rate (CGR) is the rate at which crack length increases over time, indicating the rate at which a crack expands over a period of time. The CGR indicates the rate at which bone damage worsens. A higher CGR indicates that under specific stress conditions, the crack propagates rapidly, increasing the risk of fracture.

[0109] S8: Determine the extent 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 bone damage index based on bone crack characteristics:

[0112] μ=λ1L+λ2V+λ3K+λ4G

[0113] 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.

[0114] Among them, those skilled in the art can set the weight coefficient λ1 of crack length, the weight coefficient λ2 of crack growth rate, the weight coefficient λ3 of stress intensity factor and the weight coefficient λ4 of energy release rate according to actual conditions, and the present invention does not limit them.

[0115] In this invention, the four characteristics of crack length, propagation rate, stress intensity factor, and energy release rate each represent a different aspect of bone crack injury. By integrating these factors into a single damage index, the extent of bone damage can be more comprehensively quantified, avoiding the limitations of relying on a single indicator. This helps accurately determine the severity of the injury and the risk of crack propagation, while simplifying the complex assessment 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<μ1, the degree of bone injury is determined to be grade I mild injury.

[0118] When μ1≤μ<μ2, the degree of bone injury is determined to be grade II moderate injury.

[0119] When μ2≤μ<μ3, the degree of bone injury is determined to be grade III severe injury.

[0120] When μ≥μ3, the degree of bone injury is determined to be grade IV extremely severe injury.

[0121] Wherein, μ1 represents the first bone damage index threshold, μ2 represents the second bone damage index threshold, and μ3 represents the third bone damage index threshold.

[0122] Among them, those skilled in the art can set the first bone injury index threshold μ1, the second bone injury index threshold μ2 and the third bone injury index threshold μ3 according to actual conditions, and the present invention does not limit them.

[0123] In this study, bone injury classification is based on a bone injury index corresponding to different thresholds. This not only simplifies injury assessment and provides a more standardized diagnostic approach, but also provides an important reference for personalized treatment and prognosis. This grading system offers significant benefits for fracture prevention, treatment decision-making, risk management, and patient communication, while also improving the accuracy and efficiency of clinical assessments.

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

[0125] In the present invention, the incremental unit deletion method is used in the finite element analysis process to dynamically simulate the bone crack expansion process, and then the degree of bone damage is evaluated based on the formed bone cracks, thereby improving the accuracy of bone damage assessment, guiding emergency treatment and routine training, and providing faster and more convenient decision-making support for actual rescue.

[0126] Reference Manual Figure 2 , showing a structural schematic diagram of a shock wave-induced bone damage simulation system based on dynamic crack propagation provided by the present invention.

[0127] The present invention further provides a system 20 for simulating bone damage caused by shock waves based on dynamic crack propagation, which is applied to the above-mentioned method for simulating bone damage caused by shock waves based on dynamic crack propagation, and comprises:

[0128] Processor 201.

[0129] The memory 202 stores computer-readable instructions. When the computer-readable instructions are executed by the processor 201 , the method for simulating shock wave-induced bone damage based on dynamic crack propagation as described in the method embodiment is implemented.

[0130] The shock wave-induced bone damage simulation system 20 based on dynamic crack extension provided by the present invention can execute the above-mentioned shock wave-induced bone damage simulation method based on dynamic crack extension and achieve the same or similar technical effects. To avoid repetition, the present invention will not elaborate on it.

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

[0132] In the present invention, the incremental unit deletion method is used in the finite element analysis process to dynamically simulate the bone crack expansion process, and then the degree of bone damage is evaluated based on the formed bone cracks, thereby improving the accuracy of bone damage assessment, guiding emergency treatment and routine 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 (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or 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 read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (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 and not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0135] The above embodiments can be implemented in whole or in part through software, hardware (such as circuits), firmware, or any other combination. 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 program are loaded or executed on a computer, the processes or functions described in accordance with 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 device. 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 via a wired method (such as infrared, wireless, microwave, etc.). 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 data center that contains a collection of one or more available media. The available medium can be a magnetic medium (such as a floppy disk, hard disk, or magnetic tape), an optical medium (such as a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state drive.

[0136] It should be understood that the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. A and B can be singular or plural. Furthermore, the character " / " as used herein generally indicates an "or" relationship between the associated objects, but it may also indicate an "and / or" relationship. For specific understanding, please refer to the context.

[0137] In this disclosure, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or plural.

[0138] It should be understood that in various embodiments of the present invention, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0139] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

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

[0141] In the 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 merely a logical function division. In actual implementation, there may be other division methods, such as 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 mutual coupling or direct coupling or communication connection shown or discussed can be through some interface, indirect coupling or communication connection of the device or unit, which can be electrical, mechanical or other forms.

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

[0143] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0144] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0145] An embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, the method for simulating shock wave-induced bone damage based on dynamic crack propagation as described in the method embodiment is implemented.

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

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

[0148] In the present invention, the incremental unit deletion method is used in the finite element analysis process to dynamically simulate the bone crack expansion process, and then the degree of bone damage is evaluated based on the formed bone cracks, thereby improving the accuracy of bone damage assessment, guiding emergency treatment and routine training, and providing faster and more convenient decision-making support for actual rescue.

[0149] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

[0150] There are a few points to note:

[0151] (1) The drawings of the embodiments of the present invention only relate to the structures related to the embodiments of the present invention. Other structures may refer to conventional designs.

[0152] (2) For the sake of clarity, the thickness of layers or regions in the drawings used to describe the embodiments of the present invention are exaggerated or reduced, that is, these drawings are not drawn to scale. It is 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 may be "directly" "on" or "under" the other element or intervening elements may be present.

[0153] (3) In the absence of conflict, the embodiments of the present invention and the features therein may be combined with each other to form new embodiments.

[0154] The above are only specific embodiments 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 based on 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 the material properties of the 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 for bone tissue under blast wave loading; S6: Dynamically simulate the bone crack propagation process using the incremental element deletion method; S7: extracting bone crack features of the formed bone crack; S8: Determine the degree of bone damage based on the bone crack characteristics; 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 degradation of the Young's modulus of the grid unit according to changes in 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.

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

5. The method for simulating bone damage caused by shock waves based on dynamic crack propagation according to claim 1, 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 mesh unit after degradation is determined: Yes a =E0[1-α1min(F1,1)-α2min(F2,1)] Among them, E a represents the Young's modulus of the mesh element after degradation, E0 represents the initial Young's modulus, α1 represents the tensile failure coefficient, and α2 represents the compressive failure coefficient.

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

7. The method for simulating bone damage caused by shock waves based on dynamic crack propagation according to claim 6, characterized in that: The stress intensity factor is specifically: Where K represents the stress intensity factor, γ represents the bone shape factor, σ represents the stress, and L represents the crack length; The energy release rate is specifically: Where G represents the energy release rate, and E represents the elastic modulus of 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.

8. The method for simulating bone damage caused by shock waves based on dynamic crack propagation according to claim 7, characterized in that: The S8 specifically includes: S801: Calculate the bone damage index based on the bone crack characteristics: μ=λ1L+λ2V+λ3K+λ4G Wherein, μ represents the bone damage index, λ1 represents the weight coefficient of crack length, λ2 represents the weight coefficient of crack growth rate, λ3 represents the weight coefficient of stress intensity factor, and λ4 represents the weight coefficient of 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; Wherein, μ1 represents the first bone damage index threshold, μ2 represents the second bone damage index threshold, and μ3 represents the third bone damage index threshold.

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