Method for evaluating failure spectrum boundary of vulnerable organs of human body in sitting posture under broadband impact

Abstract

The invention relates to the technical field of human body vulnerable organ failure evaluation under vibration impact, and particularly discloses a sitting posture human body vulnerable organ failure spectrum boundary evaluation method under broadband impact. The method comprises the following steps: firstly, obtaining fault picture data of a target organ structure; establishing a three-dimensional geometric model of the target organ; establishing a high-fidelity finite element model, and verifying the accuracy of the high-fidelity finite element model; a complex vibration impact load is simplified into a sine acceleration load; then carrying out statistics on typical injury modes of the target organ in a broadband interval; obtaining a critical failure envelope asymptotic curve in a broadband interval, and verifying the reasonability of the curve; and after normalizing and standardizing the critical failure envelope curve, obtaining impact failure boundary spectrums of the target organ of the human body under different injury degrees. According to the method for evaluating the failure spectrum boundary of the vulnerable organs of the sitting posture human body under the broadband impact, the injury effect of various complex loading waveforms on the human body can be effectively evaluated, then technical support is provided for human body protection design, and the engineering application potential is huge.

Description

Technical Field

[0001] The invention relates to the technical field of failure assessment of vulnerable organs of the human body under vibration impact, and in particular to a failure spectrum boundary assessment method of vulnerable organs of the human body in a sitting position under broadband impact. Background Art

[0002] Impact or road bump loads are transmitted to people through structures in the form of high-intensity vibrations, causing blunt injuries to the body's bone-bearing organs, posing a huge threat to people's health and life safety. Casualty data show that the human lumbar spine-pelvic area is the most vulnerable area with a high mortality rate. The human body vibration impact injury assessment method can provide core technical support for rapid assessment of personnel injuries and protection design, and has important basic research value and engineering guidance significance.

[0003] Existing evaluation methods are mainly divided into two categories: (1) Evaluation criteria based on the response strength of human organs, such as the critical damage threshold of various organs under static and dynamic loading conditions, which are usually represented by the numerical values ​​of organ response acceleration, force and bending moment; (2) Evaluation criteria based on the strength of external input loads, which are usually represented by the physical peak values ​​of acceleration, velocity and displacement of the impact environment in which the human body is located. In addition, the current national military standard GJB2689-96 "Safety Limits of Surface Ship Impact on Human Body" takes into account the influencing factors of the average acceleration, maximum velocity and time to reach the maximum velocity of external input loads, and stipulates the safety limit of the vertical impact environment of the surface ship hull caused by underwater non-contact explosion on the crew and the threshold of different impact damage levels caused to the crew. However, for the response strength of human organs, the damage threshold varies greatly due to the influence of loading rate, and its applicability needs further exploration. In addition, from the perspective of practical application, even if there is a specific human organ impact response strength that can be used as a damage criterion, it still cannot be extended to engineering applications. Because it is impossible to monitor and measure the dynamic response of human internal organs over a large area in a real impact environment, the actual application value is limited. For the external input load intensity, existing studies have confirmed that a single input load intensity peak or the current national military standard cannot reasonably assess the degree of human injury in a complex impact environment. Therefore, the human body vibration impact injury assessment method in a complex impact environment is still a difficult problem that needs to be solved urgently. Summary of the invention

[0004] The purpose of the present invention is to provide a failure spectrum boundary assessment method for vulnerable organs of the sitting human body under broadband impact. The method takes the impact environment of the human body as basic data, obtains the failure envelope boundary formed by the critical failure impact load based on the pseudo-velocity response spectrum characterization principle, and performs standardized processing to finally obtain the broadband impact failure boundary spectrum.

[0005] To achieve the above object, the present invention provides a method for evaluating the failure spectrum boundary of vulnerable organs of a sitting human body under broadband impact, comprising the following steps:

[0006] S1. Perform CT scanning on the target organ of the human body to obtain tomographic image data of the target organ structure;

[0007] S2, performing three-dimensional reconstruction based on the CT scan image data of the target organ to obtain a three-dimensional geometric model of the target organ;

[0008] S3. Perform structured meshing based on the three-dimensional geometric model of the target organ, assign material constitutive model parameters to each tissue, and establish a high-fidelity finite element model of the target organ;

[0009] S4. Verify the accuracy of the high-fidelity finite element model of the target organ according to the test conditions;

[0010] S5. Simplify the complex vibration impact load in the impact environment of the human body into a sinusoidal acceleration load with a single frequency and different peak values;

[0011] S6, applying the simplified load in step S5 to the finite element model of the target organ, performing batch calculations, obtaining critical failure loads at different frequencies, and statistically analyzing typical damage patterns of the target organ at different frequency intervals;

[0012] S7, listing the critical impact failure loads in the wide frequency range in four logarithmic coordinates, selecting the spectrum velocity peaks in sections, and forming a critical failure envelope asymptotic curve;

[0013] S8. Use the impact failure theory formula of single-degree-of-freedom structure in low, medium and high frequency ranges to verify the rationality of the critical failure envelope curve;

[0014] S9, regularizing and standardizing the critical failure envelope curve, and finally obtaining the failure boundary spectrum of the human target organ in a wide frequency range, and repeating the above steps S6 to S8, and finally obtaining the impact failure boundary spectrum of the human target organ under different damage degrees.

[0015] Preferably, in step S2, the acquired tomographic image data is imported into three-dimensional reconstruction software, and the geometric figures of the relevant tissues are obtained according to the gray value differences of different tissues in the CT image; the bone threshold is set according to the gray value of different tissues to establish the corresponding coating, and the contour line of the three-dimensional structure is extracted based on the continuous layer to complete the three-dimensional structure reconstruction of the continuous tomographic image.

[0016] Preferably, step S3 specifically includes the following steps:

[0017] S31, importing the 3D reconstructed geometric model obtained in step S2 into the pre-processing software, and geometrically cleaning and repairing the perfect bone contour surface again;

[0018] S32. Based on the relative position relationship between the lumbar spine and pelvis of the sitting human body, different bone tissues are assembled, and appropriate unit types are selected to divide the structured grids of each tissue in turn to achieve refined modeling;

[0019] S33. Add relevant soft tissue structures. For the main load-bearing tissues of the lumbar spine and pelvis, cortical bone and cancellous bone, use strain rate-related model constitutive parameters. At the same time, set strain failure criteria for the bone load-bearing organs composed of cortical bone and cancellous bone to form a high-fidelity finite element model for numerical simulation calculations.

[0020] Preferably, step S6 specifically includes the following steps:

[0021] S61, applying the equivalent simplified impact load in step S5 to the finite element model created in step S3 to perform batch calculation;

[0022] S62, sequentially changing the frequency and peak value of the equivalent load to obtain the critical impact failure loads within a wide frequency range and at different single frequencies.

[0023] Preferably, the specific process of step S8 is as follows:

[0024] The sitting human body is simplified into a single-degree-of-freedom mass-spring oscillator model, and the rationality of the failure envelope asymptotic curve is verified using the single-degree-of-freedom structural impact failure theoretical formula.

[0025] For the failure boundary of the isospectral displacement segment:

[0026]

[0027] For failure boundaries of isospectral velocity segments:

[0028]

[0029] For failure boundaries of isospectral acceleration segments:

[0030]

[0031] Where: c is the critical failure stress of the structure, which is generally taken as the yield stress of the material; S is the cross-sectional area of ​​the dangerous section in the load-bearing direction; k is the spring stiffness; λ is the load coefficient; κ is the structural shape coefficient; ρ is the density of the structural material; is the speed of sound in the structural material, E is the elastic modulus of the structural material; m is the concentrated mass of the structure.

[0032] Preferably, step S9 specifically includes the following steps:

[0033] S91, normalizing the failure envelope asymptotic curve obtained in step S8;

[0034] S92. Define moderate injury, mild injury and safety range, and define the stress state of bone structure corresponding to different degrees of injury;

[0035] S93, repeating the above steps S6 to S8, and performing standardization processing, and finally obtaining the impact failure boundary spectrum of the target organ of the human body under different damage degrees.

[0036] Therefore, the present invention adopts the above-mentioned method for evaluating the failure spectrum boundary of vulnerable organs of the sitting human body under broadband impact, and the beneficial effects are as follows:

[0037] (1) The present invention uses the impact environment of the human body in real-time monitoring as basic data, and uses the finite element numerical calculation method to construct a mapping relationship between the intensity of the impact environment and the degree of organ damage, thereby avoiding the complex technical requirements for direct measurement of the response of human organs;

[0038] (2) The broadband impact failure boundary spectrum obtained by the present invention can effectively evaluate the damage effects of various complex loading waveforms on the human body, thereby providing technical support for human body protection design and having great potential for engineering applications.

[0039] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a flow chart of an embodiment of a method for evaluating failure spectrum boundaries of vulnerable organs of a sitting human body under broadband impact of the present invention;

[0041] Figure 2 The invention is a three-dimensional geometric reconstruction process of lumbar-pelvic organs based on CT scanning data in an embodiment of the method for evaluating the failure spectrum boundary of vulnerable organs of a sitting human body under broadband impact;

[0042] Figure 3 It is a high-fidelity lumbar spine-pelvic finite element model of a moderately sitting human body according to an embodiment of the method for evaluating the failure spectrum boundary of a vulnerable organ of a sitting human body under broadband impact of the present invention;

[0043] Figure 4 It is the accuracy verification of the lumbar spine-pelvic finite element model of the embodiment of the method for evaluating the failure spectrum boundary of vulnerable organs of the sitting human body under broadband impact of the present invention;

[0044] Figure 5 It is an equivalent simplified impact load acceleration curve of an embodiment of a method for evaluating failure spectrum boundaries of vulnerable organs of a sitting human body under broadband impact of the present invention;

[0045] Figure 6It is a statistics of typical lumbar vertebra-pelvic injury patterns of an embodiment of the method for evaluating the failure spectrum boundary of vulnerable organs of a sitting human body under broadband impact of the present invention, wherein (a)-(d) represent lumbar vertebra-pelvic loss patterns in the interval of 2 Hz-8 Hz, (e)-(h) represent lumbar vertebra-pelvic loss patterns in the interval of 10 Hz-100 Hz, and (i)-(l) represent lumbar vertebra-pelvic loss patterns in the interval of 150 Hz-1000 Hz;

[0046] Figure 7 The invention is a comparison between a failure envelope asymptotic curve of a human body in a sitting position with a wide-band interval and a theoretical curve of a human body in a sitting position with a lumbar spine-pelvic vibration impact injury in an embodiment of the method for evaluating the failure spectrum boundary of a human body vulnerable organ in a sitting position under a wide-band impact;

[0047] Figure 8 It is the failure boundary spectra of different damage levels after standardized processing of the embodiment of the failure spectrum boundary assessment method for vulnerable organs of sitting human body under broadband impact of the present invention, wherein (a) represents the regularization and standardized processing of critical failure boundaries, and (b) represents the assessment and verification of human body damage by underwater explosion test data. DETAILED DESCRIPTION

[0048] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0049] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0050] like Figure 1 As shown, this embodiment takes the lumbar spine-pelvis, which is the most vulnerable part of a sitting human body, as an example, and the method for evaluating the failure spectrum boundary of a sitting human body's vulnerable organs under broadband impact includes the following steps:

[0051] S1. Perform CT scanning on the target organ of the human body to obtain the tomographic image data of the target organ structure; Figure 2 The figure shows the three-dimensional geometric reconstruction process of the lumbar spine and pelvic organs based on CT scan data. The CT image data comes from adult male volunteers without relevant orthopedic diseases.

[0052] S2, performing three-dimensional reconstruction based on the CT scan image data of the target organ to obtain a three-dimensional geometric model of the target organ;

[0053] The acquired CT tomographic image data is imported into the 3D reconstruction software. The 3D reconstruction software used in this embodiment is Avizo. The geometric figures of the related tissues are obtained according to the gray value differences of different tissues in the CT image. The bone threshold is set according to the gray value of different tissues to establish the corresponding coating, and the contour line of the 3D structure is extracted based on the continuous layer to complete the 3D structure reconstruction of the continuous tomographic images.

[0054] S3. Perform structured meshing based on the three-dimensional geometric model of the target organ, and refer to the literature to assign material constitutive model parameters with strain effect and strain failure criterion to each tissue, and establish Figure 3 High-fidelity finite element model of the target organ shown.

[0055] Step S3 specifically includes the following steps:

[0056] S31, importing the 3D reconstructed geometric model obtained in step S2 into pre-processing software, the pre-processing software selected in this embodiment is Hypermesh, and geometrically cleaning and repairing the perfect bone contour surface again;

[0057] S32. Based on the relative position relationship between the lumbar spine and pelvis of the sitting human body, different bone tissues are assembled, and appropriate unit types are selected to divide the structured grids of each tissue in turn to achieve refined modeling;

[0058] S33. Add relevant soft tissue structures, such as ligaments, etc. For the main load-bearing tissues of the lumbar spine and pelvis, cortical bone and cancellous bone, use strain rate-related model constitutive parameters, and models such as Johnson-Cook and Cowper-Symonds can be selected. At the same time, set strain failure criteria for the bony load-bearing organs composed of cortical bone and cancellous bone, and finally realize a high-fidelity lumbar spine-pelvis finite element model that can be used for numerical simulation calculations.

[0059] S4. Verify the accuracy of the high-fidelity finite element model of the target organ according to the test conditions; e.g. Figure 4 As shown, the accuracy of the impact response of the lumbar spine-pelvis finite element model, such as force and displacement data, was verified using human experimental loading settings and result data.

[0060] S5, such as Figure 5 As shown in the figure, the complex vibration impact load in the impact environment of the human body is simplified into a sinusoidal acceleration load with a single frequency and different peak values, so as to determine the critical impact failure load under a single frequency;

[0061] S6, applying the simplified load in step S5 to the finite element model of the target organ, performing batch calculations, obtaining critical failure loads that can cause initial damage to the target organ model at different frequencies, and statistically analyzing typical damage patterns of the target organ at different frequency intervals;

[0062] The specific steps include:

[0063] S61, applying the equivalent simplified impact load in step S5 to the lumbar spine-pelvic finite element model created in step S3 to perform batch calculation;

[0064] S62. Change the frequency and peak value of the equivalent load in sequence to obtain the critical impact failure load that can cause the lumbar spine-pelvis to reach a critical damage state within the wide frequency range and at different single frequencies. For example, a frequency of 10 Hz, a peak velocity of 4.5 m / s, a frequency of 150 Hz, and a peak velocity of 12 m / s are all critical impact failure loads.

[0065] like Figure 6 As shown in the figure, the typical injury patterns of the lumbar spine and pelvis in different frequency domain intervals are statistically classified. For example, in the low-frequency interval (<10Hz), the most likely injury pattern of the lumbar spine and pelvis is T12 vertebral fracture; in the high-frequency interval (>150Hz), the most likely injury pattern of the lumbar spine and pelvis is sciatic fracture; in the medium-frequency interval (10Hz-150Hz), the lumbar spine and pelvic injury pattern is more complicated, and its injury pattern is mainly L5 vertebral fracture, sacrum S1 fracture, or these two fractures and sciatic fracture at the same time.

[0066] S7, such as Figure 7 As shown in the figure, based on the pseudo-velocity shock spectrum characterization principle, a series of critical shock failure loads in a wide frequency range are listed in four logarithmic coordinate diagrams, and the spectrum velocity peaks are selected segmentally, such as Figure 7 As shown by the thin black solid line, the peak values ​​of the response spectra of critical impact loads of different frequencies are connected in sequence to form the critical failure envelope asymptotic curve in a wide frequency range;

[0067] like Figure 7 The “V”-shaped red dotted line shows that the physical meaning of this asymptote is: when the pseudo-velocity response spectrum value of any impact environment in which the human body is located exceeds the failure envelope asymptote of this target organ, it means that this target organ has suffered a corresponding degree of impact damage, that is, the impact load will definitely cause severe fractures of the lumbar spine-pelvis of the sitting human body;

[0068] S8. Use the impact failure theory formula of single-degree-of-freedom structure in low, medium and high frequency ranges to verify the rationality of the critical failure envelope curve;

[0069] The specific process is as follows:

[0070] The sitting human body is simplified into a single-degree-of-freedom mass-spring oscillator model, and the rationality of the failure envelope asymptotic curve is verified using the single-degree-of-freedom structural impact failure theoretical formula.

[0071] For the failure boundary of the isospectral displacement segment:

[0072]

[0073] For failure boundaries of isospectral velocity segments:

[0074]

[0075] For failure boundaries of isospectral acceleration segments:

[0076]

[0077] Where: c is the critical failure stress of the structure, which is generally taken as the yield stress of the material; S is the cross-sectional area of ​​the dangerous section in the load-bearing direction; k is the spring stiffness; λ is the load coefficient, and for a half-sine wave load, λ=1.47 is taken; κ is the structural shape coefficient, and for a rod-shaped structure, κ=1 is taken; ρ is the density of the structural material; is the speed of sound in the structural material, E is the elastic modulus of the structural material; m is the concentrated mass of the structure.

[0078] The equivalent mass of the sitting human body is m = 60.67 kg; the equivalent stiffness of the lumbar spine-pelvis is k = 144000 + 49340 N / m = 193340 N / m; because the cancellous bone has low strength and is prone to fracture, σ is taken c =5Mpa, the yield limit of cancellous bone; ρ = 1200kg / m 3 ; E = 93.7Mpa. In the low frequency range (isospectral displacement segment), the main injury mode of the lumbar spine-pelvis is T12 vertebral fracture, and S = 0.0015m 2 is the equivalent cross-sectional area of ​​vertebral cancellous bone; in the high-frequency range (isospectral acceleration segment), the main injury mode of lumbar spine-pelvis is sciatic fracture, at this time, S = 0.006m 2 It is the initial contact area between the sciatic bone and the gluteal muscles.

[0079] Since the sinusoidal load coefficient λ is unknown for the time being and the lumbar-pelvic structure is relatively irregular, the structural shape coefficient κ is difficult to determine, so it is assumed that λ = κ = 1. Substituting the above values ​​into formulas (1)-(3) in turn, we can obtain Dc = 38.8 mm, Vc = 14.9 m / s, Ac = 49.4 g, and its position in the pseudo-velocity impact response spectrum is as follows: Figure 7 As shown by the thick solid blue line, it can be seen that the asymptotes obtained based on a series of critical failure loads are consistent with the failure boundaries obtained by the theoretical formula in terms of numerical magnitude and distribution trend in the isospectral displacement and isospectral acceleration stages, proving the rationality and accuracy of using the pseudo-velocity impact response spectrum to characterize the failure boundary of the sitting human lumbar spine-pelvic impact. In addition, if λ / κ=5.4, then Vc=80m / s obtained by the theoretical formula is closer to the failure envelope asymptote.

[0080] S9. Regularize and standardize the critical failure envelope curve, and finally obtain the failure boundary spectrum of the human target organ in a wide frequency range, define the corresponding relationship between different stress level states and the degree of damage, such as mild damage and moderate damage, repeat the above steps S6 to S8, and finally obtain the impact failure boundary spectrum of the human target organ under different degrees of damage.

[0081] The specific steps include:

[0082] S91. To facilitate the promotion of the impact failure boundary spectrum in practical engineering applications, the failure envelope asymptotic curve of the sitting human lumbar spine-pelvis obtained in step S8 is standardized; Figure 8 The red part in (a) shows the failure boundary spectrum of severe impact injury of the lumbar spine and pelvis (boundary 1, the bone structure of the personnel is completely broken, unable to continue to perform job duties, and loses the ability to act and save themselves).

[0083] S92. At the same time, in order to comprehensively assess the degree of human injury, the definition of moderate injury (partial fracture of the bone structure of the personnel, who can continue to perform their job functions within a limited time and have the ability to save themselves), mild injury (slight bone fracture of the bone structure of the personnel, who can perform their job functions normally and have the ability to save themselves) and safe (the personnel have no substantial injury) ranges continues, and the stress states corresponding to the bone structure at different degrees of injury are defined respectively, such as the elastic strength limit (16MPa) corresponding to moderate injury, and 50% of the elastic strength limit (0.8MPa) corresponding to mild injury;

[0084] S93, repeat the above steps S6 to S8, and perform standardization processing, and finally obtain the impact failure boundary spectrum of the target organ of the human body under different damage degrees. Figure 8 Boundary 1 (severe damage failure boundary spectrum Dc=38.8mm, Vc=80m / s, Ac=49.4g), boundary 2 (moderate damage failure boundary spectrum, Dc=12.4mm, Vc=26m / s, Ac=15.8g), and boundary 3 (mild damage failure boundary spectrum, Dc=6.2mm, Vc=13m / s, Ac=7.9g) shown in (a).

[0085] The impact environment of a real ship deck under an underwater explosion is listed in the failure map, such as Figure 8 As shown by the black solid line in (a), it can be seen that the response spectrum value of the actual ship impact environment intensity in the range of 7-25Hz exceeds the severe damage failure boundary spectrum, which proves that the lumbar spine-pelvis of the sitting human body must have an overall fracture at this time, such as Figure 8 This real case proves that the method for assessing lumbar spine-pelvic injury of a sitting human body in a broadband vibration impact environment proposed in the present invention has great potential in practical engineering applications.

[0086] Therefore, the present invention adopts the above-mentioned method for evaluating the failure spectrum boundary of vulnerable organs of the sitting human body under broadband impact, which is convenient for real-time monitoring of the impact environment of the human body as the basic data. With the help of the finite element numerical calculation method, a mapping relationship between the intensity of the impact environment and the degree of organ damage is constructed, avoiding the complex technical requirements for direct measurement of the response of human organs; at the same time, the obtained broadband impact failure boundary spectrum can effectively evaluate the damage effects of various complex loading waveforms on the human body, thereby providing technical support for human protection design, and has great potential for engineering application.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for evaluating the failure spectrum boundary of vulnerable organs of a sitting human body under broadband impact, characterized in that: The following steps are involved: S1. Perform CT scanning on the target organ of the human body to obtain tomographic image data of the target organ structure; S2, performing three-dimensional reconstruction based on the CT scan image data of the target organ to obtain a three-dimensional geometric model of the target organ; S3. Perform structured meshing based on the three-dimensional geometric model of the target organ, assign material constitutive model parameters to each tissue, and establish a high-fidelity finite element model of the target organ; S4. Verify the accuracy of the high-fidelity finite element model of the target organ according to the test conditions; S5. Simplify the complex vibration impact load in the impact environment of the human body into a sinusoidal acceleration load with a single frequency and different peak values; S6, applying the simplified load in step S5 to the finite element model of the target organ, performing batch calculations, obtaining critical failure loads at different frequencies, and statistically analyzing typical damage patterns of the target organ at different frequency intervals; S7, listing the critical impact failure loads in the wide frequency range in four logarithmic coordinates, selecting the spectrum velocity peaks in sections, and forming a critical failure envelope asymptotic curve; S8. Use the impact failure theory formula of single-degree-of-freedom structure in low, medium and high frequency ranges to verify the rationality of the critical failure envelope curve; S9, regularizing and standardizing the critical failure envelope curve, and finally obtaining the failure boundary spectrum of the human target organ in a wide frequency range, and repeating the above steps S6 to S8, and finally obtaining the impact failure boundary spectrum of the human target organ under different damage degrees.

2. The method for evaluating failure spectrum boundaries of vulnerable organs of a sitting human body under broadband impact according to claim 1, characterized in that: In step S2, the acquired tomographic image data is imported into the three-dimensional reconstruction software, and the geometric figures of the relevant tissues are obtained according to the gray value differences of different tissues in the CT image; the bone threshold is set according to the gray value of different tissues to establish the corresponding coating, and the contour line of the three-dimensional structure is extracted based on the continuous layer to complete the three-dimensional structure reconstruction of the continuous tomographic image.

3. The method for evaluating the failure spectrum boundary of vulnerable organs of a sitting human body under broadband impact according to claim 2, characterized in that: Step S3 specifically includes the following steps: S31, importing the 3D reconstructed geometric model obtained in step S2 into the pre-processing software, and geometrically cleaning and repairing the perfect bone contour surface again; S32. Based on the relative position relationship between the lumbar spine and pelvis of the sitting human body, different bone tissues are assembled, and appropriate unit types are selected to divide the structured grids of each tissue in turn to achieve refined modeling; S33. Add relevant soft tissue structures. For the main load-bearing tissues of the lumbar spine and pelvis, cortical bone and cancellous bone, use strain rate-related model constitutive parameters. At the same time, set strain failure criteria for the bone load-bearing organs composed of cortical bone and cancellous bone to form a high-fidelity finite element model for numerical simulation calculations.

4. The method for evaluating the failure spectrum boundary of vulnerable organs of a sitting human body under broadband impact according to claim 3, characterized in that: Step S6 specifically includes the following steps: S61, applying the equivalent simplified impact load in step S5 to the finite element model created in step S3 for batch calculation; S62. The frequency and peak value of the equivalent load are changed in sequence to obtain the critical impact failure loads within a wide frequency range and at different single frequencies.

5. The method for evaluating failure spectrum boundaries of vulnerable organs of a sitting human body under broadband impact according to claim 4, characterized in that: The specific process of step S8 is as follows: The sitting human body is simplified into a single-degree-of-freedom mass-spring oscillator model, and the rationality of the failure envelope asymptotic curve is verified using the single-degree-of-freedom structural impact failure theoretical formula. For the failure boundary of the isospectral displacement segment: For failure boundaries of isospectral velocity segments: For failure boundaries of isospectral acceleration segments: Where: c is the critical failure stress of the structure, which is generally taken as the yield stress of the material; S is the cross-sectional area of ​​the dangerous section in the load-bearing direction; k is the spring stiffness; λ is the load coefficient; κ is the structural shape coefficient; ρ is the density of the structural material; is the speed of sound in the structural material, E is the elastic modulus of the structural material; m is the concentrated mass of the structure.

6. The method for evaluating the failure spectrum boundary of vulnerable organs of a sitting human body under broadband impact according to claim 5, characterized in that: Step S9 specifically includes the following steps: S91, normalizing the failure envelope asymptotic curve obtained in step S8; S92. Define moderate injury, mild injury and safety range, and define the stress state of bone structure corresponding to different degrees of injury; S93, repeating the above steps S6 to S8, and performing standardization processing, and finally obtaining the impact failure boundary spectrum of the target organ of the human body under different damage degrees.

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