A digital human viscera simulation verification method and system considering self-weight creep

Abstract

This invention provides a digital human internal organ simulation verification method and system considering self-weight creep, belonging to the field of digital human biomechanical simulation technology. The method includes establishing a three-dimensional finite element model of digital human internal organs and assigning static material parameters determined by quasi-static mechanical loading tests; constructing a static creep simulation condition consistent with the static preparation stage of a real cadaver impact experiment, and applying a gravity field to simulate to a mechanical steady state; extracting node coordinates to reconstruct the model, assigning high strain rate dynamic material parameters, and constructing a dynamic impact condition; simulating according to the dynamic loading parameters, and outputting physical quantities of the same measurement type corresponding to the anatomical location. The beneficial effects of this invention are that it solves the technical contradiction of material parameter strain rate mismatch, eliminates the initial gap between the simulation model and the carrier; ensures that the initial simulation conditions are consistent with the static preparation stage of cadaver experiments, avoiding systematic deviations in verification results; and uses the rate of change of contact mesh number for judgment, avoiding errors caused by subjective judgment.

Description

Technical Field

[0001] This application relates to the field of digital human biomechanical simulation technology, and more specifically, to a digital human internal organ simulation verification method and system that takes into account self-weight creep. Background Technology

[0002] Digital human body models are widely used in fields such as virtual collision simulation and automotive safety protection. The accuracy of the mechanical response of their internal organs directly determines the reliability of human injury risk assessment. Currently, the industry-standard verification method is to compare the results of dynamic simulation with measured data from cadaver impact experiments to calibrate the model parameters.

[0003] The existing technology has two core defects: First, internal organs are highly sensitive to strain rate, and the high strain rate dynamic material parameters required for collision simulation are significantly different from the material properties under static conditions. Second, in real experiments, internal organs will undergo self-weight creep and adhere to the carrier during the static preparation stage, but the existing simulation directly uses the initial geometric model, which cannot reproduce this process. This results in an initial gap between the model and the carrier, ultimately causing systematic deviations in the simulation results and insufficient verification reliability.

[0004] In view of the above, this application is hereby submitted. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a digital human internal organ simulation verification method that considers self-weight creep, which is particularly suitable for solving the problem of initial gap in simulation caused by mismatch in material parameter strain rate, thereby improving the accuracy of internal organ mechanical verification results.

[0006] The technical solution adopted in this invention is as follows: Firstly, a digital human internal organ simulation verification method considering self-weight creep is provided, comprising the following steps: A three-dimensional finite element model of the internal organs of the human body is established, and the static material mechanical parameters of the internal organs, which are determined by quasi-static mechanical loading test, are assigned to the three-dimensional finite element model. A static creep simulation condition consistent with the static preparation stage of a real corpse impact experiment was constructed. A gravity field was applied to the three-dimensional finite element model to perform static creep simulation until the three-dimensional finite element model reached a mechanical steady state. Extract the three-dimensional spatial coordinate data of all nodes of the three-dimensional finite element model under mechanical steady state, update and replace the initial node position information of the three-dimensional finite element model, and reconstruct the three-dimensional finite element model after self-weight creep. The three-dimensional finite element model is given the dynamic material mechanical parameters of internal organs determined by high strain rate dynamic mechanical loading test, and a dynamic impact simulation condition consistent with the dynamic impact stage of real corpse impact experiment is constructed. Simulation calculations are performed based on the dynamic loading parameters of the dynamic impact phase of a real cadaver impact experiment, and the output is a physical quantity of the same measurement type and corresponding anatomical location as the specimen in the dynamic impact phase of the real cadaver impact experiment.

[0007] Furthermore, it also includes the following steps: The output physical quantities are compared and verified with the measurement data of the corresponding anatomical positions of the specimens in the dynamic impact phase of the real cadaver impact experiment. The material parameters of the three-dimensional finite element model are adjusted within the range of pre-determined dynamic material mechanical parameters of internal organs until the mechanical response law output by the simulation is consistent with the experimental measurement data.

[0008] Furthermore, establishing a static creep simulation condition includes the following steps: The three-dimensional finite element model is placed on top of the finite element plate component, the finite element plate component is fixed, and a contact relationship is established between the three-dimensional finite element model and the finite element plate component; Apply a standard gravity load to the three-dimensional finite element model and start the static creep simulation calculation.

[0009] Furthermore, the method for determining that the three-dimensional finite element model has reached a mechanically steady state includes the following steps: Output the pressure force cloud diagram of the finite element plate component, and count the number of mesh elements subjected to pressure on the finite element plate component at each time step with a first preset step size; Calculate the rate of change of the number of compressed grid cells in adjacent time steps; When the rate of change is less than a first threshold, the three-dimensional finite element model is determined to have reached a mechanical steady state.

[0010] Furthermore, the mesh size of the finite element plate component is no greater than 1 / 3 of the mesh size of the three-dimensional finite element model.

[0011] Furthermore, the physical quantities include impact force-time curves, displacement-time curves, and stress distribution cloud maps.

[0012] Secondly, a digital human internal organ simulation verification system considering self-weight creep is provided, including: The model building module is used to construct three-dimensional finite element models of digital human internal organs and has the ability to assign quasi-static material mechanics parameters. The static creep simulation module is used to apply a gravity field to the three-dimensional finite element model to perform static creep simulation. It has the ability to construct equivalent simulation conditions and determine mechanical steady state during the static preparation stage of the corpse impact experiment. The model reconstruction module is used to extract the node coordinates of the three-dimensional finite element model and has the ability to reconstruct the geometry after creep. The dynamic working condition construction module is used to assign the dynamic material mechanical parameters of internal organs determined by high strain rate dynamic mechanical loading test to the three-dimensional finite element model, and has the ability to construct equivalent simulation working conditions for the dynamic impact stage of the corpse impact test. The simulation calculation module is used to perform high strain rate dynamic impact simulation calculations and output physical quantities of the same measurement type corresponding to the dissected location.

[0013] Furthermore, it also includes a verification and optimization module, which is used for iterative optimization of model material parameters and has the ability to verify simulation results against experimental measurement data.

[0014] Furthermore, the static creep simulation module includes: The static boundary definition unit is used to generate finite element plate components and has the ability to define the contact boundary conditions between the internal organ model and the load-bearing components. The gravity loading unit is used to apply standard gravity load to the three-dimensional finite element model and has the ability to start static creep simulation tasks. The steady-state automatic determination unit is configured to have the ability to monitor contact pressure distribution, count the number of pressure grids, and automatically identify creep steady state.

[0015] The advantages and positive effects of this invention are: it solves the technical contradiction of material parameter strain rate mismatch and effectively eliminates the initial gap between the simulation model and the carrier; it makes the initial simulation conditions completely consistent with the static preparation stage of the cadaver experiment literature, avoiding systematic deviations in the verification results; and it makes judgments based on the rate of change of the number of contact meshes, avoiding errors caused by subjective judgment. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating a simulation verification method according to an embodiment of the present invention. Detailed Implementation

[0018] The present disclosure will now be described more fully with reference to the accompanying drawings, which illustrate exemplary embodiments of the present disclosure. The technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present disclosure, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present disclosure without creative effort are within the scope of protection of the present disclosure.

[0019] like Figure 1 As shown, this invention provides a digital human internal organ simulation verification method considering self-weight creep, comprising the following steps: S10. Establish a three-dimensional finite element model of the internal organs of the human body, and assign the three-dimensional finite element model the static material mechanical parameters of the internal organs determined by the quasi-static mechanical loading test. Specifically, the process involves acquiring three-dimensional geometric data of digital human internal organs, creating a three-dimensional finite element model of these organs through mesh generation, and assigning static material mechanical parameters of the internal organs, determined through quasi-static mechanical loading tests, to the three-dimensional finite element model. Methods for acquiring three-dimensional geometric data include at least CT scans, MRI scans, and laser scans, and may also include, but are not limited to, downloading from medical image databases, reverse reconstruction of anatomical structures, and parametric geometric modeling. Mesh generation methods include at least tetrahedral mesh generation, hexahedral mesh generation, and hybrid mesh generation, and may also include, but are not limited to, adaptive mesh generation, multi-scale mesh generation, and boundary layer mesh refinement. The three-dimensional finite element model is implemented using mainstream finite element simulation software such as LSDYNA, ABAQUS, and ANSYS. The static creep simulation stage can employ a viscoelastic constitutive model, including but not limited to the generalized Maxwell model, the standard linear solid model, and the Burger model. The corresponding simulation software can be defined using viscoelastic material cards, and the input parameters include at least the bulk modulus, short-term tangential modulus, long-term tangential modulus, and attenuation coefficient.

[0020] S20. Construct a static creep simulation condition consistent with the static preparation stage of the impact experiment on a real corpse. Apply a gravity field to the three-dimensional finite element model to perform static creep simulation until the three-dimensional finite element model reaches mechanical steady state. Specifically, a static creep simulation condition (obtained from publicly available literature on real-life cadaver impact experiments) consistent with the static preparation stage is constructed. This includes setting the load-bearing components, constraints, and contact relationships between internal organs and the load-bearing components. A gravity field is applied to the three-dimensional finite element model to perform static creep simulation until the model reaches mechanical steady state. Load-bearing component types include at least flat plate components, curved components, and anatomically matched components, and may also include, but are not limited to, complex curved surface components simulating human body cavities, multi-component combined load-bearing components, etc. Gravity load settings include at least standard gravitational acceleration (9.8 m / s²), and may also include, but are not limited to, gravity loads in different directions, and non-standard gravity loads simulating hypergravity / weightlessness environments. Mechanical steady-state determination methods include at least methods based on the rate of change of the number of contact meshes, and may also include, but are not limited to, methods based on the maximum displacement rate of change, methods based on the rate of change of nodal stress, and methods based on the rate of change of system energy, etc. All simulation calculations can be implemented using an explicit dynamic solver.

[0021] S30. Extract the three-dimensional spatial coordinate data of all nodes of the three-dimensional finite element model under mechanical steady state, update and replace the initial node position information of the three-dimensional finite element model, and reconstruct the three-dimensional finite element model after self-weight creep. The node coordinate extraction methods should at least include the export function built into the simulation software, export from third-party post-processing software, and may also include, but are not limited to, batch extraction using custom scripts, real-time extraction via application programming interfaces (APIs), etc. The model reconstruction methods should at least include overall node coordinate replacement, and may also include, but are not limited to, local node coordinate replacement, mesh deformation mapping reconstruction, geometric surface fitting reconstruction, etc.

[0022] S40. Assign dynamic material mechanical parameters of internal organs, determined through high strain rate dynamic mechanical loading tests, to the three-dimensional finite element model after self-weight creep, and establish a dynamic impact simulation condition consistent with the dynamic impact stage of a real cadaver impact experiment. The types of dynamic material mechanical parameters should at least include dynamic elastic modulus, dynamic yield strength, and strain rate sensitivity coefficient, and may also include, but are not limited to, dynamic viscoelastic parameters, fracture toughness, and damage evolution parameters. The types of dynamic impact conditions should at least include frontal impact, side impact, and oblique impact, and may also include, but are not limited to, conditions with different impactor shapes (spherical, cylindrical, blunt), different impact masses, and different constraint forms.

[0023] S50. Perform simulation calculations based on the dynamic loading parameters of the dynamic impact phase of a real cadaver impact experiment, and output physical quantities of the same measurement type and corresponding anatomical location as the specimen in the dynamic impact phase of the real cadaver impact experiment. The dynamic loading parameter types include at least impact velocity, impact location, and loading time, and may also include, but are not limited to, impact acceleration curves, impact force curves, constraint loading curves, etc.

[0024] By employing the above method, the static self-weight creep stage and the dynamic impact stage are decoupled, and material parameters with corresponding strain rates are used respectively, thus resolving the technical contradiction of material parameter strain rate mismatch. By reconstructing the geometric shape of the model after creep steady state, the initial gap of the simulation is eliminated, making the initial simulation conditions completely consistent with the real physical experiment. The output of physical quantities of the same type and location as the experiment ensures the rigor and effectiveness of subsequent verification and improves the reliability of simulation results.

[0025] To further improve the biological realism of the model, a result comparison and parameter optimization step is added to the basic simulation process. This embodiment provides an implementation method.

[0026] In one embodiment, the simulation verification method further includes the following steps: The output physical quantities are compared and verified with the measurement data of the corresponding anatomical positions of the specimens in the dynamic impact phase of the real cadaver impact experiment. The material parameters of the three-dimensional finite element model are adjusted within the range of pre-determined dynamic material mechanical parameters of internal organs until the mechanical response law output by the simulation is consistent with the experimental measurement data.

[0027] Using the above method, this application proposes a two-step simulation verification process with dynamic and static phased decoupling, which fundamentally solves the technical contradiction of material parameter strain rate mismatch and effectively eliminates the initial gap between the simulation model and the carrier; it makes the initial simulation conditions completely consistent with the static preparation stage of real cadaver experiments, avoiding systematic deviations in the verification results; through the benchmarking and verification of simulation results and experimental measurement data, the accuracy of the model can be quantitatively evaluated; a complete model verification and optimization closed loop is formed, which can obtain a highly biologically realistic finite element model of internal organs.

[0028] In one embodiment, setting up a static creep simulation condition includes the following steps: The three-dimensional finite element model is placed on top of the finite element plate component, the finite element plate component is fixed, and a contact relationship is set between the three-dimensional finite element model and the finite element plate component. Apply a standard gravity load to the three-dimensional finite element model and start the static creep simulation calculation.

[0029] In one embodiment, the method for determining whether a three-dimensional finite element model has reached a mechanically steady state includes the following steps: Output the pressure force cloud diagram of the finite element plate component, and count the number of mesh elements subjected to pressure on the finite element plate component at each time step with a first preset step size. The first preset step size is preferably 100ms. Calculate the number of compressed grids in adjacent time steps and rate of change The equation is as follows: ; When the rate of change is less than a first threshold, the three-dimensional finite element model is determined to have reached a mechanical steady state. The first threshold is preferably 1%.

[0030] Using the above method, the existing technology relies entirely on subjective judgment to determine creep steady state. Usually, the simulation termination time is manually determined by observing whether the deformation curve is flat. This application determines steady state by monitoring the rate of change of the number of compressed mesh elements on the load-bearing component. The number of compressed mesh elements is counted at a fixed time step, and the mechanical steady state is determined by the rate of change of the number of elements in adjacent time steps. This achieves objective and automatic determination of creep steady state, eliminates human error, and ensures the consistency and repeatability of simulation results between different models and different operators.

[0031] In one embodiment, the mesh size of the finite element plate component is no greater than 1 / 3 of the mesh size of the three-dimensional finite element model. The plate mesh size is smaller than the liver model mesh size, which accurately captures the boundary of the contact area and avoids distortion in contact pressure calculation caused by mesh size mismatch.

[0032] In one embodiment, the static material mechanical parameters include elastic modulus, Poisson's ratio, yield strength, and stress-strain relationship; for the liver model, the Poisson's ratio of the three-dimensional finite element model is set to 0.495 to ensure that the model volume is conserved during static creep.

[0033] In one embodiment, the steps for establishing a three-dimensional finite element model of the spleen include: using a 3.0T MRI device to perform a thin-slice scan of the upper abdominal region of the volunteer, with a slice thickness of 0.8mm, to obtain complete three-dimensional geometric morphology and anatomical structure data of the spleen; reconstructing the three-dimensional model of the spleen based on the MRI image data, using hexahedral mesh elements for mesh generation, with the mesh size controlled between 1.5mm and 3mm; determining the static material mechanical parameters of the spleen through a quasi-static mechanical loading test, and assigning them to the finite element model of the spleen, with the Poisson's ratio set to 0.495.

[0034] A finite element model of an arc-shaped flat plate was constructed as the load-bearing platform for the spleen, with a mesh size of 0.5 mm. The finite element model of the spleen was placed on top of the arc-shaped flat plate, the plate was fixed, and contact relationships were established. A standard gravity load was applied, and a static creep simulation was initiated. The number of meshes under pressure was counted at 50 ms time steps, and the rate of change was calculated. When the rate of change was less than 0.5%, the spleen model was considered to have reached a mechanical steady state. The steady-state node coordinates were extracted, and the finite element model of the spleen after self-weight creep was reconstructed. Dynamic material mechanics parameters of the spleen were assigned, and a dynamic impact simulation of the spleen was constructed. Dynamic simulation calculations were performed, and the impact force-time curves and strain distribution contour maps of the corresponding anatomical locations of the spleen were output.

[0035] In one embodiment, the physical quantity types that output corresponding to the anatomical location and are of the same measurement type include at least impact force-time curves, displacement-time curves, and stress distribution cloud maps, and may also include, but are not limited to, acceleration-time curves, strain distribution cloud maps, energy change curves, and damage distribution cloud maps.

[0036] To better utilize a digital human viscera simulation verification method that considers self-weight creep, this invention also provides a digital human viscera simulation verification system that considers self-weight creep, comprising: The model building module is used to construct three-dimensional finite element models of digital human internal organs and has the ability to assign quasi-static material mechanics parameters. The static creep simulation module is used to apply a gravity field to a three-dimensional finite element model to perform static creep simulation. It has the ability to construct equivalent simulation conditions and determine mechanical steady state during the static preparation stage of the cadaver impact experiment. The model reconstruction module is used to extract the node coordinates of the three-dimensional finite element model and has the ability to reconstruct the geometry after creep. The dynamic working condition construction module is used to assign dynamic material mechanical parameters of internal organs to the three-dimensional finite element model through high strain rate dynamic mechanical loading test, and has the ability to construct equivalent simulation working conditions for the dynamic impact stage of the corpse impact test. The simulation calculation module is used to perform high strain rate dynamic impact simulation calculations and output physical quantities of the same measurement type corresponding to the dissected location.

[0037] In one embodiment, the system further includes a verification and optimization module for iterative optimization of model material parameters, which has the ability to verify the simulation results against experimental measurement data.

[0038] In one embodiment, the static creep simulation module includes: Static boundary definition element, used to generate finite element plate components, has the ability to define the contact boundary conditions between the internal organ model and the load-bearing components; Gravity loading unit, used to apply standard gravity load to three-dimensional finite element model, has the ability to start static creep simulation tasks; The steady-state automatic determination unit is configured to have the ability to monitor contact pressure distribution, count the number of pressure grids, and automatically identify creep steady-state conditions.

[0039] In one embodiment, both static and dynamic material mechanical parameters were determined using an ex vivo tissue compression test. During the sampling stage, healthy ex vivo liver tissue was selected, wrapped in gauze soaked in isotonic saline, and stored... Environment prepared for use. During sample preparation, frozen liver tissue was sliced ​​into 5×5×5mm cubes, taken from the core region of the liver, avoiding blood vessels and the capsule. During testing, an unconfined compression test was conducted using a mechanical testing machine. The sample was placed on the testing platform, the indenter was lowered until a small contact force was detected, then the displacement and force values ​​were zeroed and loading was initiated. The quasi-static test loading rate was 1 mm / min, corresponding to the low strain rate range; the high strain rate test loading rate was 100 mm / min, corresponding to the strain rate range of the dynamic impact simulation. Load-displacement curves were recorded and converted into stress-strain curves for fitting the parameters of the corresponding constitutive model.

[0040] In one embodiment, parameter optimization is carried out in two stages, with different adjustment priorities and targets for each stage. In the static creep stage, within the experimentally determined parameter range, material density is adjusted first, followed by the bulk modulus, tangential modulus, and attenuation coefficient of the viscoelastic constitutive model, with the creep steady-state contact state and deformation as optimization targets. In the dynamic impact stage, within the experimentally determined parameter range, the tangential modulus and corresponding constitutive index of the hyperelastic constitutive model are mainly adjusted, with the peak impact force, peak displacement, and mechanical response curve trend as optimization targets. The convergence criterion for parameter adjustment is that the mechanical response law output by simulation is consistent with the experimental measurement data, and the error at key feature points is within an acceptable range.

[0041] In one embodiment, the self-weight creep process is characterized by a gradual load, with the model primarily undergoing large deformation creep, preventing drastic degradation of the mesh quality. After the node coordinates are replaced, the mesh quality check function of the finite element preprocessing software can be used to verify indicators such as element aspect ratio, warpage, and Jacobian determinant value. Mesh elements that do not meet the quality requirements are then identified and corrected through local smoothing and node fine-tuning to ensure that the reconstructed model mesh quality meets the computational requirements of dynamic simulation.

[0042] This embodiment provides a preferred implementation method, taking the human liver organ as an example, and describes in detail the complete technical solution of this application.

[0043] A 64-slice spiral CT scanner was used to perform thin-slice scans of the thoracic and abdominal cavities of volunteers, with a slice thickness of 1 mm, to acquire complete three-dimensional spatial geometric morphology and anatomical structure data of the liver. Based on the CT image data, a three-dimensional liver model was reconstructed using medical image processing software, and the geometric features of the liver were extracted. Finite element preprocessing software was used to mesh the three-dimensional liver model, employing tetrahedral mesh elements with a mesh size controlled between 2 mm and 5 mm to ensure mesh quality met simulation requirements. Quasi-static mechanical loading tests were conducted to determine the material mechanical parameters of the liver under static load. The measured static material parameters were then assigned to the liver finite element model, where Poisson's ratio... The value was set to 0.495 to ensure the model volume is conserved during static creep. A viscoelastic constitutive model was used during the static creep stage, corresponding to the *MAT_VISCOELASTIC material card in the LS-DYNA software. Input parameters included bulk modulus, short-term tangential modulus, long-term tangential modulus, and BETA attenuation coefficient. Based on the volumetric strain formula in elasticity: ; in, It is the change in volume. For the initial volume, For axial strain, when If the volume change is less than 1%, the model volume can be approximated as conserved, ensuring the authenticity of deformation during static creep.

[0044] A static creep simulation was constructed, consistent with the static preparation stage of a real cadaver impact experiment. A finite element plate component was established as the load-bearing platform for the liver, with a mesh size of 1 mm, not exceeding 1 / 3 of the liver model's mesh size. The liver finite element model was placed on top of the finite element plate component, and all degrees of freedom of the finite element plate component were fixed using the boundary constraint function (*BOUNDARY keyword) of the finite element simulation software LSDYNA. A surface-to-surface contact relationship was established between the liver finite element model and the finite element plate component, with a static friction coefficient FS=0.3, a dynamic friction coefficient FD=0.3, a principal face penalty stiffness scaling factor SFM=1, and a secondary face penalty stiffness scaling factor SFS=1. A standard gravity load was applied to the liver finite element model using the *LOAD_BODY(ACCELERATION) keyword, and the static creep simulation calculation was initiated. The simulation time was set to 10 s, and the time step was set to 10 ms. All simulation calculations were completed using the LS-DYNA explicit solver.

[0045] Output the pressure contour map of the finite element plate component. With a time step of 100ms, count the number of mesh elements on the finite element plate component subjected to pressure at each time step. Calculate the rate of change of the number of mesh elements under pressure in adjacent time steps. When the rate of change is less than 1%, the liver finite element model is considered to have reached mechanical steady state. At this time, the liver model has completed the self-weight creep flattening process and achieved close contact with the finite element plate component.

[0046] The three-dimensional spatial coordinate data of all nodes of the liver finite element model under steady-state mechanical conditions were extracted. This coordinate data was used to replace the node position information of the initial liver geometry model, reconstructing the liver finite element model after self-weight creep. The material mechanical parameters of the liver under dynamic loading were determined through high strain rate dynamic mechanical loading tests. The measured dynamic material parameters were then assigned to the reconstructed liver finite element model. Core parameters of the dynamic impact condition were extracted from publicly available literature on cadaver impact experiments, including an impact velocity of 10 m / s, an impact location at the anterior edge of the left lobe of the liver, an impact mass of 5 kg, and a loading time of 10 ms. A dynamic impact simulation condition consistent with the dynamic impact phase of a real cadaver impact experiment was constructed. Simulation calculations were performed according to the extracted dynamic loading parameters, outputting physical quantities of the same measurement type and anatomical location as those in the dynamic impact phase of the real cadaver impact experiment, including the impact force-time curve and displacement-time curve at the anterior edge of the left lobe of the liver, as well as a stress distribution cloud map of the entire liver.

[0047] Based on embodiments of this disclosure, this disclosure also provides an electronic device, a readable storage medium, and a computer program product.

[0048] An electronic device includes at least one processor and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the digital human internal organ simulation verification method provided in this disclosure.

[0049] Electronic devices are intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. Electronic devices can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the present disclosure described and / or claimed herein.

[0050] A non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to cause a computer to execute the digital human internal organ simulation verification method provided in this disclosure.

[0051] The various embodiments of this disclosure can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), complex programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0052] A computer program product includes a computer program / instructions, which are executed by a processor using the digital human internal organ simulation verification method disclosed herein.

[0053] The program code used to implement the methods of this disclosure may be written in any combination of one or more programming languages. This program code may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may be executed entirely on a machine, partially on a machine, as a standalone software package partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0054] In the context of this disclosure, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium can be, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0055] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A digital human internal organ simulation verification method considering self-weight creep, characterized in that, Includes the following steps: A three-dimensional finite element model of the internal organs of the human body is established, and the static material mechanical parameters of the internal organs, which are determined by quasi-static mechanical loading test, are assigned to the three-dimensional finite element model. A static creep simulation condition consistent with the static preparation stage of a real corpse impact experiment was constructed. A gravity field was applied to the three-dimensional finite element model to perform static creep simulation until the three-dimensional finite element model reached a mechanical steady state. Extract the three-dimensional spatial coordinate data of all nodes of the three-dimensional finite element model under mechanical steady state, update and replace the initial node position information of the three-dimensional finite element model, and reconstruct the three-dimensional finite element model after self-weight creep. The three-dimensional finite element model is given the dynamic material mechanical parameters of internal organs determined by high strain rate dynamic mechanical loading test, and a dynamic impact simulation condition consistent with the dynamic impact stage of real corpse impact experiment is constructed. Simulation calculations are performed based on the dynamic loading parameters of the dynamic impact phase of a real cadaver impact experiment, and the output is a physical quantity of the same measurement type and corresponding anatomical location as the specimen in the dynamic impact phase of the real cadaver impact experiment.

2. The simulation verification method according to claim 1, characterized in that, It also includes the following steps: The output physical quantities are compared and verified with the measurement data of the corresponding anatomical positions of the specimens in the dynamic impact phase of the real cadaver impact experiment. The material parameters of the three-dimensional finite element model are adjusted within the range of pre-determined dynamic material mechanical parameters of internal organs until the mechanical response law output by the simulation is consistent with the experimental measurement data.

3. The simulation verification method according to claim 1, characterized in that, Setting up a static creep simulation condition involves the following steps: The three-dimensional finite element model is placed on top of the finite element plate component, the finite element plate component is fixed, and a contact relationship is established between the three-dimensional finite element model and the finite element plate component; Apply a standard gravity load to the three-dimensional finite element model and start the static creep simulation calculation.

4. The simulation verification method according to claim 3, characterized in that, The method for determining whether the three-dimensional finite element model has reached a mechanical steady state includes the following steps: Output the pressure force cloud diagram of the finite element plate component, and count the number of mesh elements subjected to pressure on the finite element plate component at each time step with a first preset step size; Calculate the rate of change of the number of compressed grid cells in adjacent time steps; When the rate of change is less than a first threshold, the three-dimensional finite element model is determined to have reached a mechanical steady state.

5. The simulation verification method according to claim 3, characterized in that: The mesh size of the finite element plate component is no greater than 1 / 3 of the mesh size of the three-dimensional finite element model.

6. The simulation verification method according to claim 1, characterized in that: The physical quantities include the impact force-time curve, the displacement-time curve, and the stress distribution cloud map.

7. A digital human internal organ simulation and verification system considering self-weight creep, implementing the method as described in claim 1, characterized in that, include: The model building module is used to construct three-dimensional finite element models of digital human internal organs and has the ability to assign quasi-static material mechanics parameters. The static creep simulation module is used to apply a gravity field to the three-dimensional finite element model to perform static creep simulation. It has the ability to construct equivalent simulation conditions and determine mechanical steady state during the static preparation stage of the corpse impact experiment. The model reconstruction module is used to extract the node coordinates of the three-dimensional finite element model and has the ability to reconstruct the geometry after creep. The dynamic working condition construction module is used to assign the dynamic material mechanical parameters of internal organs determined by high strain rate dynamic mechanical loading test to the three-dimensional finite element model, and has the ability to construct equivalent simulation working conditions for the dynamic impact stage of the corpse impact test. The simulation calculation module is used to perform high strain rate dynamic impact simulation calculations and output physical quantities of the same measurement type corresponding to the dissected location.

8. The simulation verification system according to claim 7, characterized in that, Also includes: The verification and optimization module is used for iterative optimization of model material parameters and has the ability to verify simulation results against experimental measurement data.

9. The simulation verification system according to claim 7, characterized in that, The static creep simulation module includes: Static boundary definition element, used to generate finite element plate components, has the ability to define the contact boundary conditions between the internal organ model and the load-bearing components; The gravity loading unit is used to apply standard gravity loads to the three-dimensional finite element model and has the ability to start static creep simulation tasks. The steady-state automatic determination unit is configured to have the ability to monitor contact pressure distribution, count the number of pressure grids, and automatically identify creep steady-state conditions.

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