Human body trauma equivalent evaluation method

Abstract

The invention discloses a human body part tissue trauma equivalent evaluation method, and belongs to the field of human body trauma ballistic science. The method comprises the following steps of: firstly, obtaining a human body part tissue thickness-fragment residual velocity curve and an equivalent structure thickness-fragment residual velocity curve under the same fragment and initial velocity conditions by virtue of finite element and test design means; and by using the curve, when the tissue composition, thickness and fragment initial velocity of the human body part are known, obtaining the corresponding equivalent structure thickness. Then, an equivalent structure thicken-V50 value curve is obtained through a test, and a V50 value corresponding to the equivalent structure thickness is obtained from the equivalent structure thicken-V50 value curve; and finally, comparing the initial speed of the fragments with the V50 value, and judging whether the fragments can penetrate through the part of the human body or not. According to the method, rapid and quantitative judgment on whether the human body penetrates or not under the given fragment-speed condition is achieved through the three-step process of hyperbola mapping and V50 value criterion, and the method is an evaluation method which can avoid the ethical problem, can guarantee high precision and repeatability and is relatively low in cost.

Description

Technical Field

[0001] This invention belongs to the field of human trauma ballistics and impact protection technology, and specifically relates to an efficient, repeatable, and ethical equivalent assessment method that combines computer simulation and equivalent material testing to evaluate the penetrability of fragments to various parts of the human body. Background Technology

[0002] In fields such as military medicine and personal protective equipment development, accurately assessing the traumatic effects of projectiles such as shrapnel and projectiles on the human body (especially the highly lethal head) is crucial. Traditional assessment methods mainly rely on: biological experiments: using animal experiments or human simulants (such as gelatin and soap). Animal experiments are ethically controversial, and biological differences between species make extrapolating results to humans uncertain; while materials such as gelatin mainly simulate soft tissue, and the simulation accuracy for bones is insufficient. Real human skull experiments: difficult to obtain and have significant ethical issues, extremely high experimental costs, and cannot be used for large-scale parametric studies. Pure numerical simulation: Although finite element software (such as LS-DYNA) can simulate the fragment penetration process, due to the complexity of the constitutive relationship of human structural materials, individual differences, and the difficulty in accurately modeling material failure behavior under high-speed impact, the confidence and universality of directly determining penetration based solely on simulation results are often challenged.

[0003] Currently, some studies use homogeneous aluminum or steel as equivalent targets, but their mechanical response differs significantly from that of human bone, leading to large evaluation errors. Therefore, there is an urgent need in this field for an evaluation method that can avoid ethical issues, ensure high accuracy and repeatability, and is relatively low in cost. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for evaluating the equivalence of human trauma.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: Using finite element method and experimental design, firstly, under the same fragment and initial velocity conditions, the functional relationship curves between the tissue thickness of the human body part and the residual velocity of the fragment, and the functional relationship curves between the thickness of different glass fiber reinforced polyphenylene sulfide composite boards and the residual velocity of the fragment are calculated. Using these two curves, given the thickness of the human head tissue and the initial velocity of the fragment, the corresponding equivalent glass fiber composite board thickness can be obtained. Subsequently, the V50 value curves for different glass fiber composite board thicknesses are obtained through experiments, and the V50 value corresponding to that glass fiber composite board thickness is obtained from them. Finally, the initial velocity of the fragment is compared with the V50 value to determine whether the fragment can penetrate the human body part, thereby achieving the objective of the present invention.

[0006] This invention relates to a method for equivalent assessment of tissue trauma in human body parts, characterized by the following assessment steps: 1) Determine the tissue composition and thickness of the human body parts, and clarify the fragment structure; 2) Determine the relationship curve between tissue thickness and residual fragment velocity in human body parts. A simulation model of fragment penetration into human tissue is established, consisting of fragments and human tissue, wherein the proportion of human tissue of different thicknesses is consistent with the actual proportion; based on the fragment structure defined in step 1), an appropriate mass and initial velocity are selected; using finite element simulation technology, the relationship curve between the thickness of human tissue and the remaining velocity of the fragment is determined. 3) Determine the equivalent structural materials for human body parts and the basis and criteria for equivalence assessment. Based on the mechanism of trauma caused by fragments penetrating human tissue structures, the equivalent structural material of human tissue was determined to be glass fiber reinforced polyphenylene sulfide composite material with a fiber volume content of 40%. The equivalence criterion was the residual velocity after fragment penetration. The judgment criterion was that the residual velocity after fragment penetration of human tissue structure was equal to that of the equivalent structure of human tissue. 4) Determine the relationship curve between the equivalent structural thickness of human tissue and the residual velocity of the fragment. A simulation model of the equivalent structure of the tissue penetrated by the fragments in the human body was established, wherein the glass fiber reinforced polyphenylene sulfide composite material plate of the equivalent structure of the human body tissue was modeled in a layered manner; the same fragment as in step 2) was selected; the relationship curve between the thickness of the equivalent structure of the human body tissue and the remaining velocity of the fragment was determined using finite element simulation technology. 5) Obtain the curve showing the relationship between the equivalent structural thickness of human tissue and the V50 value. According to GJB 4300A-2012, the relationship curve between the equivalent structural thickness of human tissue and V50 value was obtained by penetration test; 6) Assess whether tissues in the body have been penetrated by fragments. The thickness of the components of human tissue other than bones is scaled down by a ratio of 3 to 5:1 to obtain the equivalent bone thickness. Based on the sum of bone thickness and equivalent bone thickness, the equivalent structural thickness of human tissue is determined by the curve of the relationship between human tissue thickness and residual velocity of fragments determined in step 2) and the curve of the relationship between equivalent structural thickness of human tissue and residual velocity of fragments determined in step 3). The equivalent structural thickness of human tissue is then determined by the curve of the relationship between equivalent structural thickness of human tissue and residual velocity. Based on the determined equivalent structural thickness of the human body tissue and the relationship curve between the equivalent structural thickness of the human body tissue and the remaining velocity of the fragment determined in step 4), the V50 value corresponding to the equivalent structural thickness of the human body tissue is obtained. The following formula is used to evaluate whether the human body tissue has been penetrated by the fragment:

[0007] in, It's the fragmentation rate; It is for the mass of fragment simulation; It is the mass used for fragmentation testing; That's 50% of the fragment's penetration speed; When the initial velocity of the fragment is not less than In the case of a fragment penetrating the head tissues, the fragments will penetrate the head tissues; otherwise, the head tissues will not be penetrated.

[0008] Preferably, in step 2), when determining the relationship curve between human tissue thickness and the remaining velocity of the fragment, the fragment structure, mass, and initial velocity remain unchanged, and the human tissue thickness is no less than 5 types; the relationship curve between human tissue and the remaining velocity of the fragment is obtained by interpolation.

[0009] Preferably, in step 4), when determining the relationship curve between the equivalent structural thickness and the remaining velocity of the fragment, there are no fewer than 5 types of equivalent structural thickness; the relationship curve between the equivalent structural thickness of human tissue and the remaining velocity of the fragment is obtained by interpolation.

[0010] Preferably, in step 5), when obtaining the curve of the relationship between the equivalent structural thickness of human tissue and the V50 value, the equivalent structural thickness is no less than 5 types; the curve of the relationship between the equivalent structural thickness of human tissue and the V50 value is obtained by interpolation method.

[0011] Preferably, the tissues of the human body are composed of skin and bones, or skin, fat, muscles and bones.

[0012] In a further preferred embodiment, in step 6) assessing whether the tissue of a human body part is penetrated by fragments, the scaling ratio of skin thickness to bone thickness is 3.5:1, the scaling ratio of fat thickness to bone thickness is 5:1, and the scaling ratio of muscle thickness to bone thickness is 3:1.

[0013] This invention discloses an equivalent assessment method for human trauma, belonging to the field of human trauma ballistics and impact protection technology. Utilizing finite element method and experimental design techniques, firstly, under the same fragment and initial velocity conditions, the functional relationship curves between tissue thickness and residual fragment velocity at a human body location, and between different glass fiber reinforced polyphenylene sulfide (PVS) composite board thicknesses and residual fragment velocity, are calculated. Using these two curves, given the tissue thickness and initial fragment velocity of a certain human body location, the corresponding equivalent PPS composite board thickness can be obtained. Subsequently, V50 value curves for different PPS composite board thicknesses are obtained experimentally, and the corresponding V50 value is derived from these curves. Finally, comparing the initial fragment velocity with the V50 value determines whether the fragment can penetrate that part of the human body. This method achieves rapid and quantitative determination of human penetration under given fragment-velocity conditions through a three-step process of "hyperbolic mapping + V50 value criterion." It is an assessment method that avoids ethical issues, ensures high accuracy and repeatability, and is relatively low-cost. Attached Figure Description

[0014] Figure 1 This is a simulation model diagram of fragments penetrating head tissue; Figure 2 It is a graph showing the relationship between head tissue thickness and remaining velocity. Figure 3 It is an equivalent structural diagram of the fragments penetrating the head tissue; Figure 4 It is a graph showing the relationship between the equivalent structural thickness of the head tissue and the residual velocity. Figure 5 It is a curve showing the relationship between the equivalent structural thickness of head tissue and the V50 value; Figure 6 This is a simulation model of fragments penetrating chest tissue; Figure 7 It is a graph showing the relationship between chest tissue thickness and residual velocity. Figure 8 It is a graph showing the relationship between the equivalent structural thickness of the chest tissue and the residual velocity. Figure 9 It is a curve showing the relationship between the equivalent structural thickness of chest tissue and the V50 value. Detailed Implementation

[0015] To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the following examples provide a more detailed description of the invention. It should be noted that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0016] Example 1 The human body structure in this embodiment is the head, which consists of scalp and bones. The scalp is 7.2 mm thick, and the bones are 6.6 mm thick.

[0017] Cylindrical fragments were selected for the fragment geometry.

[0018] Regarding the human body structures, tissues, and fragments in this embodiment, the steps for equivalent assessment of human trauma are as follows: (1) Determine the relationship curve between head tissue thickness and residual fragment velocity. Establish a simulation model of fragment penetration into head tissues, such as Figure 1 As shown, the structure consists of fragments and local head tissue. Different head tissue thicknesses were used as input conditions, where the ratio of scalp thickness to bone thickness remained constant, consistent with the actual ratio. A fragment mass of 1.01g and an initial velocity of 394m / s were selected for finite element simulation calculations. The residual velocities after fragment penetration were obtained, and the simulation results are shown in Table 1. The head tissue thickness-residual velocity relationship curve was obtained through interpolation. Figure 2 As shown.

[0019] Table 1 Simulation results of the relationship between head tissue thickness and residual velocity

[0020] (2) Determine the equivalent structural materials for human body parts and the basis and criteria for equivalence judgment. Based on the mechanism of trauma caused by fragments penetrating human tissue structures, the equivalent structural material for human tissues was determined to be a glass fiber reinforced polyphenylene sulfide composite material with a fiber volume content of 40%. The equivalence was determined based on the residual velocity after fragment penetration, and the criterion was that the residual velocity after fragment penetration of human tissue structures was equal to that of the equivalent structure of human tissues.

[0021] (3) Determine the relationship curve between the equivalent structural thickness of the head tissue and the residual velocity of the fragment. A simulation model of the equivalent structure of fragment penetration into head tissue was established. The glass fiber reinforced polyphenylene sulfide composite material plate used for the equivalent structure of the head tissue was modeled in layers, with each layer being 0.2 mm thick. Figure 3 As shown in Table 2, finite element simulations were performed using different thicknesses of the equivalent head tissue structure as input conditions to obtain the residual velocities after fragment penetration. The simulation results are shown in Table 2, and the relationship curves between the thickness of the equivalent head tissue structure and the residual velocity are shown in Table 2. Figure 4 As shown.

[0022] Table 2 Simulation results of the equivalent structural thickness-residual velocity relationship

[0023] (4) Obtain the relationship curves between different thicknesses of the equivalent structure of head tissue and the corresponding V50 values. According to GJB 4300A-2012, fragment penetration tests were conducted on the equivalent structure of the head tissue with different thicknesses to obtain the V50 values, as shown in Table 3 below. The relationship curve between the equivalent structure thickness and the V50 value is shown in the figure below. Figure 5 As shown.

[0024] Table 3. Test results of equivalent structural thickness-V50 value

[0025] (5) Assess whether the head tissue has been penetrated. Given a scalp thickness of 7.2 mm, a bone thickness of 6.6 mm, a fragment mass of 1.2 g, and an initial velocity of 150 m / s. Based on the 6.6 mm bone thickness, through... Figure 2 The curve yielded a residual fragment velocity of 365 m / s; based on this residual fragment velocity of 365 m / s, further calculations were performed using... Figure 4The equivalent structural thickness obtained from the curve is 6.5 mm; finally, based on the equivalent structural thickness of 6.5 mm, through... Figure 5 The curve yielded a V50 value of 137 m / s corresponding to the equivalent structural thickness. Then, the following formula was used to assess whether the human head tissue structure was penetrated by fragments, resulting in trauma.

[0026]

[0027] in, It's the fragmentation rate; The mass used for fragment simulation is 1.01g; It is the mass used for fragmentation testing; That's 50% of the fragment's penetration speed.

[0028] When the initial velocity of the fragment is not less than In the case of a fragment penetrating the head tissues, the fragments will penetrate the head tissues; otherwise, the head tissues will not be penetrated.

[0029] This embodiment The calculated result is 125.7 m / s, which is less than the initial fragment velocity of 150 m / s. Therefore, the equivalent assessment result of human trauma in this embodiment is determined to be: the head tissue structure was penetrated.

[0030] Compared with existing methods that use homogeneous aluminum or steel as equivalent targets, this embodiment uses glass fiber reinforced polyphenylene sulfide composite board as the equivalent target. Its density and mechanical properties are similar to those of human bones, resulting in higher accuracy in designing equivalent targets for fragmented injuries.

[0031] Example 2 The human body structure in this embodiment is the chest, which is composed of skin, fat, muscle, and bone. The skin thickness is 3.5 mm, the fat thickness is 5.25 mm, the muscle thickness is 3.5 mm, and the bone thickness is 3.5 mm.

[0032] The geometric structure of the fragments should be square.

[0033] Regarding the human body structures, tissues, and fragments in this embodiment, the steps for equivalent assessment of human trauma are as follows: (1) Determine the relationship curve between chest tissue thickness and residual fragment velocity. Establish a simulation model of fragment penetration into chest tissue, such as Figure 6As shown, the structure consists of fragments and localized chest tissue. Different chest tissue thicknesses were used as input conditions, where the proportions of skin, fat, muscle, and bone thickness within the chest tissue were kept constant to match actual proportions. A fragment mass of 1.01g and an initial velocity of 394m / s were selected for finite element simulation calculations. The residual velocities after fragment penetration were obtained, and the simulation results are shown in Table 4. The chest tissue thickness-residual velocity relationship curve is shown in... Figure 7 As shown.

[0034] Table 4 Simulation results of the relationship between chest tissue thickness and residual velocity

[0035] (2) Determine the equivalent structural materials for human body parts and the basis and criteria for equivalence judgment. Based on the mechanism of trauma caused by fragments penetrating human tissue structures, the equivalent structural material for human tissues was determined to be a glass fiber reinforced polyphenylene sulfide composite material with a fiber volume content of 40%. The equivalence was determined based on the residual velocity after fragment penetration, and the criterion was that the residual velocity after fragment penetration of human tissue structures was equal to that of the equivalent structure of human tissues.

[0036] (3) Determine the relationship curve between the equivalent structural thickness of the chest tissue and the residual velocity of the fragment. A simulation model of the equivalent structure of fragment penetration into chest tissue was established. The equivalent structure, a glass fiber reinforced polyphenylene sulfide composite plate, was modeled in layers, with each layer 0.2 mm thick. Finite element simulations were performed with different equivalent structure thicknesses as input conditions to obtain the corresponding residual velocities after fragment penetration. The simulation results are shown in Table 5, and the equivalent structure thickness-residual velocity relationship curves are shown below. Figure 8 As shown.

[0037] Table 5 Simulation results of the equivalent structural thickness-residual velocity relationship

[0038] (4) Obtain the relationship curves between different thicknesses of the equivalent structure of the chest tissue and the corresponding V50 values. According to GJB 4300A-2012, fragment penetration tests were conducted on head tissues with different equivalent structural thicknesses to obtain V50 values, as shown in Table 6 below. The relationship curve between equivalent structural thickness and V50 value is shown in the figure below. Figure 9 As shown.

[0039] Table 6. Test results of equivalent structural thickness - V50 value

[0040] (5) Assess whether the chest tissue has been penetrated. Given that the skin thickness is 3.5 mm, the fat thickness is 5.25 mm, the muscle thickness is 3.5 mm, the bone thickness is 3.5 mm, and the fragment mass is 1.1 g, with an initial velocity of 105 m / s. Based on the 3.5 mm bone thickness, through... Figure 7 The curve yielded a residual fragment velocity of 378 m / s; based on this residual fragment velocity of 378 m / s, and through... Figure 8 The equivalent structural thickness obtained from the curve is 5.9 mm; finally, based on the equivalent structural thickness of 5.9 mm, further... Figure 9 The curve yields a V50 value of 115 m / s corresponding to the equivalent structural thickness. Then, using formula (1), it is assessed whether the human chest tissue structure is penetrated by fragments, resulting in trauma.

[0041] This embodiment The calculated result is 110.2 m / s, which is greater than the initial fragment velocity of 105 m / s. Therefore, the equivalent assessment result of human trauma in this embodiment is determined to be: the chest tissue structure was penetrated.

[0042] Compared with existing methods that use homogeneous aluminum or steel as equivalent targets, this embodiment uses glass fiber reinforced polyphenylene sulfide composite board as the equivalent target. Its density and mechanical properties are similar to those of human bones, resulting in higher accuracy in designing equivalent targets for fragmented injuries.

Claims

1. A method for equivalent assessment of tissue trauma in human body parts, characterized in that, The evaluation steps are as follows: 1) Determine the tissue composition and thickness of the human body parts, and clarify the fragment structure; 2) Determine the relationship curve between tissue thickness and residual fragment velocity in human body parts. A simulation model of fragment penetration into human tissue is established, consisting of fragments and human tissue, wherein the proportion of human tissue of different thicknesses is consistent with the actual proportion; based on the fragment structure defined in step 1), an appropriate mass and initial velocity are selected; using finite element simulation technology, the relationship curve between the thickness of human tissue and the remaining velocity of the fragment is determined. 3) Determine the equivalent structural materials for human body parts and the basis and criteria for equivalence assessment. Based on the mechanism of trauma caused by fragments penetrating human tissue structures, the equivalent structural material of human tissue was determined to be glass fiber reinforced polyphenylene sulfide composite material with a fiber volume content of 40%. The equivalence criterion was the residual velocity after fragment penetration. The judgment criterion was that the residual velocity after fragment penetration of human tissue structure was equal to that of the equivalent structure of human tissue. 4) Determine the relationship curve between the equivalent structural thickness of human tissue and the residual velocity of the fragment. A simulation model of the equivalent structure of the tissue penetrated by the fragments in the human body was established, wherein the glass fiber reinforced polyphenylene sulfide composite material plate of the equivalent structure of the human body tissue was modeled in a layered manner; the same fragment as in step 2) was selected; the relationship curve between the thickness of the equivalent structure of the human body tissue and the remaining velocity of the fragment was determined using finite element simulation technology. 5) Obtain the curve showing the relationship between the equivalent structural thickness of human tissue and the V50 value. According to GJB 4300A-2012, the relationship curve between the equivalent structural thickness of human tissue and V50 value was obtained by penetration test; 6) Assess whether tissues in the body have been penetrated by fragments. The thickness of the components of human tissue other than bones is scaled down by a ratio of 3 to 5:1 to obtain the equivalent bone thickness. Based on the sum of bone thickness and equivalent bone thickness, the equivalent structural thickness of human tissue is determined by the curve of the relationship between human tissue thickness and residual velocity of fragments determined in step 2) and the curve of the relationship between equivalent structural thickness of human tissue and residual velocity of fragments determined in step 3). The equivalent structural thickness of human tissue is then determined by the curve of the relationship between equivalent structural thickness of human tissue and residual velocity. Based on the determined equivalent structural thickness of the human body tissue and the relationship curve between the equivalent structural thickness of the human body tissue and the remaining velocity of the fragment determined in step 4), the V50 value corresponding to the equivalent structural thickness of the human body tissue is obtained. The following formula is used to evaluate whether the human body tissue has been penetrated by the fragment: in, It's the fragmentation rate; It is for the mass of fragment simulation; It is the mass used for fragmentation testing; That's 50% of the fragment's penetration speed; When the initial velocity of the fragment is not less than In the case of a fragment penetrating the head tissues, the fragments will penetrate the head tissues; otherwise, the head tissues will not be penetrated.

2. The method for equivalent assessment of human trauma according to claim 1, characterized in that: Step 2) When determining the relationship curve between human tissue thickness and residual velocity of the fragment, the fragment structure, mass and initial velocity remain unchanged, and the human tissue thickness has no less than 5 types; The curves relating tissue velocity to fragment velocity in human body parts were obtained using interpolation methods.

3. The method for equivalent assessment of human trauma according to claim 1, characterized in that: When determining the relationship curve between equivalent structural thickness and residual velocity of the fragment in step 4), the equivalent structural thickness shall be no less than 5 types; The curves relating the equivalent structural thickness of tissues in human body parts to the residual velocity of fragments were obtained using interpolation methods.

4. The method for equivalent assessment of human trauma according to claim 1, characterized in that: When obtaining the curve showing the relationship between the equivalent structural thickness of human tissue and the V50 value in step 5), the equivalent structural thickness shall be no less than 5 types. The curves showing the relationship between the equivalent structural thickness of human tissues and the V50 value were obtained through interpolation.

5. The method for equivalent assessment of human trauma according to claim 1, characterized in that: The human body tissues described herein are composed of skin and bones, or of skin, fat, muscles and bones.

6. The method for equivalent assessment of human trauma according to claim 2, characterized in that: In step 6), when assessing whether tissues in a human body part have been penetrated by fragments, the scaling ratio of skin thickness to bone thickness is 3.5:1, the scaling ratio of fat thickness to bone thickness is 5:1, and the scaling ratio of muscle thickness to bone thickness is 3:1.

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