A method for evaluating injury of a pedestrian chest impactor

Abstract

The present application relates to the technical field of pedestrian protection test evaluation, in particular to a damage evaluation method of a pedestrian chest impactor. Through simulation calculation, the key kinematic parameters affecting rib strain in pedestrian collision are identified, and a linear relationship P1 is constructed. Combined with rib mechanics experiment, a rib strain to fracture probability model P2 is established. Based on biomechanics experiment, P2 is used to evaluate the fracture risk P3 under different working conditions. A chest injury threshold is set, and P4 is obtained through a generalized binomial model. The relationship P5 between chest compression amount and injury risk is established. The chest compression amount relationship P6 is fitted through impactor test, and then the rib strain in P5 is replaced by P6 to reconstruct the target injury risk model P7. The technical scheme can establish a chest injury risk curve without specific test data, filling the defects of the current chest impactor evaluation method.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pedestrian protection test evaluation, in particular to a damage evaluation method of a pedestrian chest impactor. BACKGROUND

[0002] In the automotive industry and the field of traffic safety, pedestrian protection has always been an important research topic. With the continuous increase of the number of cars, the proportion of pedestrians injured in traffic accidents is also high, especially the severity of chest injury, which is often directly related to the survival rate and rehabilitation quality of the injured. The chest, as an important part of the human body, contains key organs such as the heart and lungs, and is surrounded by multiple ribs for protection, but in traffic accidents, the chest is extremely vulnerable to impact, resulting in rib fractures, pneumothorax, hemothorax and other serious consequences.

[0003] Pedestrian safety protection tests mainly focus on head and leg protection, and the evaluation method for chest injury is not perfect. This is mainly due to the lack of damage evaluation technology and standards specifically for pedestrian chest impact. Traditional chest injury risk curves are mostly established based on in-vehicle occupant dummies or biomechanical test results. These models and methods have significant limitations when applied to pedestrian chest injury assessment. On the one hand, although biomechanical tests can provide valuable data support, they are limited by medical ethics, sample scarcity, high experimental costs, and poor reproducibility, making it difficult to be widely applied and used in actual evaluation. On the other hand, there are significant differences in collision dynamics, biomechanical properties and injury mechanisms between in-vehicle occupants and pedestrians, so it is obviously inappropriate to directly apply in-vehicle occupant injury assessment methods to pedestrians. SUMMARY

[0004] The purpose of the present application is to provide a damage evaluation method of a pedestrian chest impactor, which can establish a chest injury risk curve without specific test data, filling the gap in current chest impactor evaluation methods.

[0005] To achieve the above-mentioned purpose, the present application provides a damage evaluation method of a pedestrian chest impactor, comprising:

[0006] A finite element human body model is used for simulation calculation to determine kinematic parameters with high correlation to rib strain in a pedestrian collision scenario, and the kinematic parameters are linearly fitted with rib strain to obtain a function P1;

[0007] A survival model is used to fit the data of rib mechanics experiments to obtain a rib strain and rib fracture probability model, and a function P2 is obtained; a human body model is used to reconstruct biomechanical tests under different working conditions, and rib strain is used to calculate the corresponding fracture risk using the function P2 to obtain a function P3; an expected chest injury probability is set, and based on the function P3, a generalized binomial probability model is used to obtain a function P4;

[0008] The function P5 is obtained by combining the function P1 with the function P4 to establish the relationship between the chest compression amount and the damage risk probability; the chest impactor compression amount is obtained by performing an impactor test; and the relationship between the chest compression amount of the human body model and the chest impactor compression amount is fitted by using a linear function to obtain the function P6; the function P7 is obtained by combining the function P5 with the function P6 and re-fitting the function after replacing the rib strain value of the function P5 with the chest impactor compression amount of the function P6.

[0009] Advantages of the basic scheme: In the absence of specific test data, the technical scheme establishes a chest damage risk curve by using a pedestrian finite element model, and forms a chest impactor corresponding damage risk curve by establishing a mapping method through an impactor test. The finite element human body model can simulate the complex biomechanical response of the human body in the collision process, and provides a more detailed and accurate means for damage evaluation.

[0010] The technical scheme first identifies kinematic parameters highly correlated with rib strain, and establishes a linear relationship (function P1) between these parameters and rib strain, providing a basis for subsequent quantification of damage risk. At the same time, the rib mechanics experimental data is fitted by using a survival model to construct a direct relationship (function P2) between rib strain and fracture probability, making the damage evaluation more specific and accurate.

[0011] By reconstructing biomechanical tests under different working conditions and using the rib strain and fracture probability model (function P2) to calculate the fracture risk (function P3), the evaluation method is ensured to be widely applicable and reliable, and the accuracy of the evaluation results is improved.

[0012] By setting the expected AIS3+ chest damage probability and further deriving based on a generalized binomial probability model (function P4), the quantification of chest damage risk is realized. At the same time, by combining the relationship between chest compression amount and AIS3+ damage risk probability (function P5), a scientific basis is provided for formulating safety standards and designing protection measures.

[0013] The bridge from simulation to experiment is built by verifying through an impactor test and fitting the relationship between the chest compression amount of the human body model and the chest impactor compression amount by using a linear function (function P6). Finally, the target function P7 is obtained by combining the function P5 with the function P6, and the function P7 can directly reflect the relationship between the chest impactor compression amount and the AIS3+ damage risk probability, filling the gap in the current chest impactor evaluation method.

[0014] As a preferred embodiment, the kinematic parameters are linearly fitted with the rib strain to obtain the function P1, including the following contents:

[0015] R2 The linear function that fits the maximum chest compression value with the rib strain is P1, where the x-axis of function P1 is the rib strain and the y-axis is the chest compression value.

[0016] As a feasible and preferred approach, a survival model is used to fit the data from rib biomechanics experiments to obtain a rib strain and rib fracture probability model, resulting in function P2, which includes the following:

[0017] The AIC value is calculated by using age as a covariate, as shown in the following formula:

[0018]

[0019] in, This represents the maximum value of the likelihood function of the model. Given the number of parameters in the model, compare the AIC values ​​of the probabilistic models and select the function with the lowest AIC value as function P2. The x-axis of function P2 represents rib strain, and the y-axis represents the probability of rib fracture.

[0020] As a feasible preferred option, the x-axis of function P3 represents rib strain, and the y-axis represents the probability of rib fracture in the corresponding human model.

[0021] As a feasible and preferred solution, based on function P3, function P4 is obtained through a generalized binomial probability model. The specific calculation method is as follows:

[0022]

[0023] in, This represents the probability of AIS3+ occurring. The probability of a rib fracture is 0. The probability of a rib fracture. The probability of two ribs being fractured. , , The first one obtained by calculating through function P3 i, j, k The probability of fracture of 12 ribs, where i ranges from 1 to 12, representing 12 ribs;

[0024] The x-axis of function P4 represents rib strain, and the y-axis represents the probability of chest injury specified by AIS.

[0025] As a feasible and preferred approach, by combining functions P1 and P4, the relationship between chest compression and the probability of injury risk is established, resulting in function P5, which includes the following:

[0026] The thoracic compression amount of the P1 function under the same strain is fitted with the AIS3+ injury risk probability of the P4 function to obtain a function P5, the abscissa of the function P5 is the rib strain, and the ordinate is the injury probability of the specified AIS.

[0027] As an implementable preferred solution, the ordinate of the function P6 is the thoracic impactor compression amount, and the abscissa is the thoracic compression amount of the human body model.

[0028] As an implementable preferred solution, the abscissa of the function P7 is the kinematic parameter value in the thoracic impactor, and the ordinate is the thoracic injury probability of the specified AIS.

[0029] As an implementable preferred solution, it further comprises collecting typical pedestrian thoracic collision injury accidents and carrying out accident reconstruction by using the thoracic impactor; the risk of the pedestrian thoracic AIS3+ is predicted by using the function P7, and the predicted result is compared with the actual thoracic injury of the pedestrian to verify the effectiveness of the function P7.

[0030] As an implementable preferred solution, it further comprises carrying out a thoracic impactor test by using a test vehicle, and evaluating the test result based on the injury risk curve of the function P7; the value of the kinematic parameter in the thoracic impactor corresponding to the AIS injury probability of 5% is set as the IARV value, and if the thoracic compression amount does not exceed the IARV value, it indicates that the evaluation of the vehicle in the thoracic impactor test is excellent, otherwise it is poor. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is a logic diagram of a pedestrian thoracic impactor injury evaluation method.

[0032] Figure 2 It is a structural schematic diagram of an electronic device of an embodiment of the present application. DETAILED DESCRIPTION

[0033] In order to make the technical solutions of the present application and the advantages thereof clearer, the technical solutions of the present application will be further described in detail below with reference to the drawings. It can be understood that the specific embodiments described herein are only part of the embodiments of the present application, and are only used to explain the present application, but not to limit the present application. It should be noted that the technical features or combinations of technical features described in the following embodiments should not be considered in isolation, and they can be combined with each other to achieve better technical effects. The same reference numerals appearing in the drawings of the following embodiments represent the same features or components, which can be applied to different embodiments.

[0034] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of the present application should be the usual meanings understood by the general technical personnel in the field to which the present application belongs.

[0035] The application will be described in further detail below with reference to the drawings:

[0036] Reference signs: electronic device 500, processor 501, communication interface 502, memory 503, bus 504.

[0037] With reference to Figure 1 A damage evaluation method of a pedestrian chest impactor, comprising:

[0038] Step S100, using a finite element human body model, simulation calculation is performed according to a set simulation matrix (such as Table 1). Determine a kinematic parameter with high correlation with rib strain under a pedestrian collision scene, in the embodiment, the kinematic parameters include chest compression, compression rate, acceleration and collision force, etc.

[0039] Table 1

[0040]

[0041] Linear fitting is performed on the kinematic parameters and the rib strain, and the linear function of the chest compression and the rib strain fitting with the maximum R 2 value is selected as P1.

[0042] Step S200, using Weibull, Log-normal and Log-logistic three survival models to fit the data of the rib cortical bone uniaxial tensile material mechanics experiment, obtain the rib strain and rib fracture probability model, take age as a covariate, calculate the AIC (Akaike Information Criterion) value to judge the function fitting quality, the formula is as follows:

[0043]

[0044] Wherein, is the maximum value of the likelihood function of the model, is the number of parameters in the model.

[0045] Compare the AIC values of the probability models, take the function with the lowest AIC value as function P2, the abscissa of function P2 is the rib strain, and the ordinate is the rib fracture probability.

[0046] Step S300: Using human models such as THUMS (Total Human Model for Safety) or GHBMC (Global Human Body Models Consortium), PMHS experiments under different working conditions are reconstructed respectively. Using the rib strain of the human model in the simulation, the corresponding fracture risk is calculated using function P2, thereby obtaining the optimized rib fracture injury risk prediction function P3. The horizontal axis of function P3 is rib strain, and the vertical axis is the rib fracture probability of the corresponding human model.

[0047] Step S400: Set the expected AIS3+ chest injury probability, i.e., the probability of fractures of 3 or more ribs in the chest. Based on function P3, obtain function P4 through a generalized binomial probability model. The specific calculation method is as follows:

[0048]

[0049] in, This represents the probability of AIS3+ occurring. The probability of a rib fracture is 0. The probability of a rib fracture. The probability of two ribs being fractured. , , The first one obtained by calculating through function P3 i, j, k The probability of fracture of 12 ribs, where i ranges from 1 to 12, representing 12 ribs;

[0050] The x-axis of function P4 represents rib strain, and the y-axis represents the probability of chest injury specified by AIS.

[0051] In step S500, combining functions P1 and P4, we take the ordinate of function P1 (chest compression) and the ordinate of function P2 (probability of AIS3+ injury risk) under the same strain, establish the relationship between chest compression and AIS3+ injury risk probability, and obtain function P5. The abscissa of function P5 is rib strain, and the ordinate is the specified AIS chest injury probability.

[0052] Step S600: Conduct an impactor test, repeat the test conditions in step S100, and use a linear function to fit the chest compression of the human model with the chest impactor compression to obtain function P6.

[0053] Step S700: Combining functions P5 and P6, replace the x-axis value of function P5 with the y-axis value (chest impactor compression) of function P6 and refit the function to obtain the target function P7, where the x-axis represents the kinematic parameter value in the chest impactor and the y-axis represents the specified AIS chest injury probability.

[0054] Step S800, collect typical pedestrian chest impact injury accidents, and use the chest impactor to carry out accident reconstruction.

[0055] The function P7 is used to predict the risk of pedestrian chest AIS3+, and if more than 50% of the AIS3+ risk probability is considered to have caused AIS3+ injury. The predicted results are compared with the actual pedestrian chest injury (whether there is AIS3+ injury) to verify the consistency of X% and above accident results with the prediction results of function P7. If the function P7 is considered to be valid, X% is set to 70% in the embodiment.

[0056] Step S900, use the test vehicle to carry out the chest impactor test, and evaluate the experimental results based on the injury risk curve of function P7. The value of the kinematic parameter corresponding to the AIS injury probability of 5% in the chest impactor is set as the IARV (Injury Assessment Reference Value) value. If the chest compression amount does not exceed the IARV value, it means that the test vehicle seat and safety belt system can effectively limit the deformation of the chest and prevent exceeding the range that may cause harm. Therefore, the evaluation of the vehicle in the chest impactor test is excellent, and vice versa.

[0057] The embodiment of the present disclosure also provides a pedestrian chest impactor injury evaluation system, which uses the above-mentioned pedestrian chest impactor injury evaluation method.

[0058] The embodiment of the present disclosure also provides a storage medium, which stores a computer program. When the computer program is executed by a processor, all steps of the above-mentioned pedestrian chest impactor injury evaluation method can be realized.

[0059] Those skilled in the art can understand that all or part of the flow of the damage evaluation method of the pedestrian thoracic impactor can be completed by a computer program instructing the relevant hardware, and the program can be stored in a non-volatile computer readable storage medium. When the program is executed, it can include the flow of each embodiment of the damage evaluation method of the pedestrian thoracic impactor. Among them, any reference to memory, storage, database or other medium used in each embodiment provided by the present application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration but not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0060] The embodiments of the present application also provide an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps of the damage evaluation method of the pedestrian thoracic impactor are implemented. In the embodiments of the present application, the processor is the control center of the computer system, which can be the processor of a physical machine or the processor of a virtual machine.

[0061] Reference Figure 2The electronic device 500 comprises at least one processor 501, at least one communication interface 502, at least one memory 503 and at least one bus 504. The bus 504 is used to realize the connection communication between the components, the communication interface 502 is used for signaling or data communication with other node devices, and the memory 503 stores machine readable instructions executable by the processor 501. When the electronic device 500 runs, the processor 501 communicates with the memory 503 through the bus 504, and the machine readable instructions are executed by the processor 501 when called. The above is only an embodiment of the present application, and the common knowledge of specific structures and characteristics in the scheme is not described in detail, and the ordinary skilled person in the art knows all the ordinary technical knowledge in the technical field of the application before the application date or the priority date, can know all the prior art in the field, and has the ability to apply conventional experimental means before the date, and the ordinary skilled person in the art can improve and implement the present scheme under the guidance of the present application, and some typical known structures or known methods should not be an obstacle for the ordinary skilled person in the art to implement the present application. It should be pointed out that for those skilled in the art, without departing from the structure of the present application, a number of modifications and improvements can be made, which should be regarded as the protection scope of the present application, and these will not affect the effect and practicality of the patent. The protection scope of the present application should be subject to the content of its claims, and the specific implementation mode in the specification can be used to explain the content of the claims.

Claims

1. A method of injury assessment for a pedestrian thoracic impactor, characterized by: Comprise: Determine the kinematic parameters with high correlation with rib strain in the pedestrian collision scene by simulation calculation using finite element human body model, linearly fit the kinematic parameters with rib strain to obtain function P1; Obtain rib strain and rib fracture probability model by fitting the data of rib mechanics experiment using survival model, obtain function P2; Obtain function P3 by using rib strain to calculate the corresponding fracture risk of the biomechanics test of the human body model under different working conditions; Set the expected chest injury probability, obtain function P4 through the generalized binomial probability model based on function P3, the specific calculation method is as follows: in, This represents the probability of AIS3+ occurring. The probability of a rib fracture is 0. The probability of a rib fracture. The probability of two ribs being fractured. , , The first one obtained by calculating through function P3 i, j, k The probability of fracture of the rib, among which i The value range is 1 to 12, representing 12 ribs; The abscissa of function P4 is rib strain, and the ordinate is the specified AIS chest injury probability; Establish the relationship between chest compression and injury risk probability of human body model by combining function P1 and function P4, obtain function P5; Obtain function P6 by fitting the chest compression of human body model with the chest impactor compression using linear function; Obtain target function P7 by replacing the rib strain value of function P5 with the chest impactor compression of function P6 after re-fitting the function, the abscissa of function P7 is the kinematic parameter value in the chest impactor, and the ordinate is the specified AIS chest injury probability.

2. The injury evaluation method of the pedestrian chest impactor according to claim 1, characterized in that: Linearly fit the kinematic parameters with rib strain to obtain function P1, which comprises the following contents: Selecting R 2 The linear function that best fits the rib strain versus chest compression data is P1, with the x-axis representing rib strain and the y-axis representing chest compression.

3. The injury evaluation method of the pedestrian chest impactor according to claim 1, characterized in that: Obtain rib strain and rib fracture probability model by fitting the data of rib mechanics experiment using survival model to obtain function P2, which comprises the following contents: Calculate AIC value by taking age as a covariate, the formula is as follows: wherein, is the maximum value of the likelihood function of the model, is the number of parameters in the model, and the AIC value of the probability model is compared, and the function with the lowest AIC value is taken as the function P2, the abscissa of the function P2 is the rib strain, and the ordinate is the rib fracture probability.

4. The method of claim 1, wherein: The abscissa of function P3 is rib strain, and the ordinate is the rib fracture probability of the corresponding human body model.

5. The method of claim 1, wherein: Establish the relationship between chest compression and injury risk probability by combining function P1 and function P4 to obtain function P5, which comprises the following contents: Take the chest compression of P1 function and the injury risk probability of AIS3+ of P4 function under the same strain to fit and obtain function P5, the abscissa of function P5 is rib strain, and the ordinate is the specified AIS injury probability.

6. The method of claim 1, wherein: The ordinate of function P6 is chest impactor compression, and the abscissa is human body model chest compression.

7. The method of claim 6, wherein: It also includes collecting typical pedestrian chest collision injury accidents and using the chest impactor to carry out accident reconstruction; Use function P7 to predict the risk of pedestrian chest AIS3+, and compare the predicted results with the actual pedestrian chest injury to verify the effectiveness of function P7.

8. The method of claim 1 or 7, wherein: It also includes using the test vehicle to carry out chest impactor test, and evaluating the test results based on the injury risk curve of function P7; Set the value of the kinematic parameter in the chest impactor corresponding to AIS injury probability 5% as IARV value, if the chest compression does not exceed the IARV value, it means that the evaluation of the vehicle in the chest impactor test is excellent, otherwise it is poor.

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