A method and system for measuring pedestrian chest compression during impact

Abstract

This invention relates to the field of automotive simulation testing technology, specifically to a method and system for measuring pedestrian chest compression during a collision. The method includes establishing a vehicle model and a pedestrian model; creating a series of vehicle-pedestrian collision response simulation cases using the vehicle and pedestrian models; designing a chest compression measurement method and outputting the chest compression for each collision response simulation case; performing a correlation analysis between the output chest compression and rib strain to obtain the chest compression measurement method most strongly correlated with chest injury; and selecting the chest compression measurement method and measurement point with the highest average correlation coefficient. This technical solution can obtain a chest compression measurement method most strongly correlated with chest injury, guiding the design and development of chest impactors.

Description

Technical Field

[0001] This invention relates to the field of automotive testing technology, specifically to a method and system for measuring the chest compression of a pedestrian in a collision. Background Technology

[0002] In pedestrian-vehicle collisions, chest injuries are a leading cause of serious injury or death for pedestrians. Therefore, it is crucial to conduct quantitative assessments of chest injury risks in vehicles and to design chest protection performance accordingly. Currently, pedestrian injury protection primarily focuses on the head, lower limbs, and pelvis, using head- and leg-shaped impactors to test the front-end structure of vehicles. However, there are no methods for testing and evaluating chest impactors, hindering vehicle design improvements. Biomechanical performance tests conducted both domestically and internationally have shown that chest compression is currently a relatively effective indicator of chest injury risk.

[0003] To develop a chest impactor, it is first necessary to study the damage mechanism using a finite element model of the human body, and simultaneously investigate the correlation between chest compression and chest injury in the human model. In the human model, the chest deformation is complex; it is affected not only by the impact of a car collision but also by other parts of the body such as the spine, muscles, and arms. Therefore, the stress-deformation and damage mechanism of the chest are very complex. During a pedestrian collision, the chest is not only subjected to pure lateral impact compression, but also undergoes overall bending and torsion. Deformation occurs at various locations throughout the chest, making the measurement of chest deformation extremely difficult. Summary of the Invention

[0004] The purpose of this invention is to propose a method and system for measuring chest compression in pedestrians during impact. This technical solution can obtain a method for measuring chest compression that is most correlated with chest injury, so as to guide the design and development of chest impactors.

[0005] To achieve the above objectives, in a first aspect, embodiments of this disclosure provide a method for measuring the chest compression of a pedestrian during a collision, comprising: establishing a vehicle model and a pedestrian model; establishing a series of vehicle-pedestrian collision response process simulation cases using the vehicle model and the pedestrian model; designing a chest compression measurement method and outputting the chest compression of each collision response process simulation case; performing a correlation analysis between the output chest compression and the rib strain to obtain the chest compression measurement method that has the greatest correlation with chest injury; and selecting the chest compression measurement method and measurement point with the highest average correlation coefficient.

[0006] Beneficial effects of the basic scheme: The ribs of the human chest are located in three-dimensional space, and during a pedestrian-vehicle collision, the chest undergoes overall movement and local deformation. The ribs deform in various directions at different locations, making the measurement of rib deformation extremely difficult. By establishing vehicle and pedestrian models, the collision process between a vehicle and a pedestrian can be simulated in a virtual environment, reducing costs. This simulation test can comprehensively evaluate the safety performance of a vehicle while ensuring safety. By designing a chest compression measurement method and establishing a virtual chest band on the human chest model, the three-dimensional deformation of the ribs can be transformed into two-dimensional deformation, more clearly revealing the deformation pattern and damage mechanism of the chest during a pedestrian-vehicle collision. By measuring the compression at chest monitoring points using different measurement methods and outputting the chest compression for each collision response simulation case, a more accurate and detailed understanding of the degree of chest compression experienced by the pedestrian during the collision can be obtained. By conducting correlation analysis between chest compression and rib strain, we can identify the chest compression measurement method that is most correlated with chest injury, thereby better reflecting the risk of chest injury, guiding the design and development of chest impactors, helping to improve vehicle structure, reducing the chest compression of pedestrians during collisions, and thus reducing the risk of pedestrian injury.

[0007] As a feasible and preferred option, a car model is established, including the following:

[0008] Select vehicle models and count their exterior dimensions. Plot the exterior dimensions of each vehicle model in the XZ coordinate system to obtain the median vehicle shape of sedans and SUVs. Use a finite element general vehicle model and adjust the finite element mesh to obtain the models of sedans and SUVs.

[0009] As a feasible and preferred approach, pedestrian modeling includes the following:

[0010] The pedestrian model uses the THUMSV 402 50th percentile model. A chest band model is set on the outside of the chest cavity of the pedestrian model. At the same time, several rib deformation monitoring points are defined counterclockwise around the center of the chest band from the sternum to monitor the deformation of the chest.

[0011] As a feasible preferred option, the chest band model is located at the horizontal position of the 2nd, 4th, 6th, 8th and 10th ribs and the lower edge of the thoracic cavity; monitoring points for rib deformation are defined at 12.5%, 20%, 25%, 30%, 37.5%, 62.5%, 70%, 75%, 80% and 87.5% of the center of the chest band, respectively, from the sternum.

[0012] As an feasible and preferred approach, the simulation cases of car-pedestrian collision response process include the car-pedestrian collision response process and the SUV-pedestrian collision response process. Each case has different car collision speed, hood height and hood angle.

[0013] As a feasible and preferred approach, a method for measuring chest compression volume is designed, including the following:

[0014] In contrast to the method for measuring spinal compression, a virtual spinal center is defined at the same height as the chest girder; a spring element is established between the measurement point and the virtual vertebral center, and the chest compression is output through the deformation of the spring element.

[0015] Compared to the compression measurement method of the virtual center of the chest band, the virtual center of the chest band is defined by the average coordinates of four nodes at the back of the sternum and ribs. A spring measurement unit is established between the measurement point and the center of the chest band. The chest compression is output through the deformation of the spring unit.

[0016] The method for measuring the compression of the entire chest involves establishing a transverse spring unit between the measurement point on the left and the corresponding point on the right, and the chest compression is output through the deformation of the spring unit.

[0017] A method for measuring hemithoracic compression of the chest relative to the sagittal plane, outputting the vertical displacement change of the measurement point relative to the sagittal plane of symmetry.

[0018] As a feasible and preferred approach, a correlation analysis is performed between the output chest compression and rib strain to obtain the chest compression measurement method that has the strongest correlation with chest injury, including the following:

[0019] In each car-pedestrian collision response simulation case, the maximum compression measured at each measurement point on each chest band using various measurement methods is extracted, and the maximum first principal strain of the cortical bone of each rib is also extracted.

[0020] The maximum chest compression measured at the k-th measurement point of the i-th chest band in all simulation cases using the j-th compression measurement method is taken as data d. If the k-th measurement point of the i-th chest band is on rib m, the maximum first principal strain of the cortical bone of the m-th rib in all simulation cases is taken as data s.

[0021] The correlation coefficient between data d and data s is calculated using the following formula:

[0022]

[0023] In the formula, n is the number of simulation cases of the collision response process, and finally the correlation between the chest compression measured at the k-th measurement point of the i-th chest strap using the j-th method and the strain of the m-th rib is obtained.

[0024] As a feasible and preferred option, the chest compression measurement method with the highest average correlation coefficient is selected, including the following:

[0025] The average correlation coefficient of each measurement method is calculated using the following formula:

[0026]

[0027] in, The number of correlation coefficients related to the j-th compression measurement method;

[0028] Compare each The method for measuring chest compression was selected based on the magnitude of the correlation coefficient, with the highest average value. This method was chosen as the final method for measuring chest compression.

[0029] As a feasible and preferred approach, the chest compression measurement point with the highest average correlation coefficient is selected, including the following:

[0030] The average correlation coefficient for each measurement point is calculated using the following formula:

[0031]

[0032] in, The number of correlation coefficients associated with the k-th measurement point;

[0033] Compare each The chest compression measurement point with the largest average correlation coefficient was selected as the final chest compression measurement point.

[0034] Secondly, embodiments of this disclosure provide a pedestrian chest impact compression measurement system, which utilizes the aforementioned pedestrian chest impact compression measurement method. Attached Figure Description

[0035] Figure 1 A schematic diagram of a method for measuring chest compression in pedestrians during impact;

[0036] Figure 2 A schematic diagram of a finite element model of a car-pedestrian collision.

[0037] Figure 3 This is a schematic diagram of the chest band model distribution;

[0038] Figure 4 A schematic diagram showing the arrangement of compression measurement points and measurement spring units on a chest girder model;

[0039] Figure 5 This is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention; Detailed Implementation

[0040] To make the technical solution and advantages of this application clearer, the technical solution of the present invention will be further described in detail below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are only some embodiments of the present invention, and are only used to explain this application, not to limit it. It should be noted that the technical features or combinations of technical features described in the following embodiments should not be considered isolated; they can be combined with each other to achieve better technical effects. The same reference numerals appearing in the accompanying drawings of the following embodiments represent the same features or components, and can be applied to different embodiments.

[0041] Furthermore, unless otherwise defined, the technical or scientific terms used in this invention description shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains.

[0042] Furthermore, it should be noted that in the description of this invention, the terms "first," "second," "third," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0043] The present invention will now be described in further detail with reference to the accompanying drawings:

[0044] Explanation of reference numerals in the attached drawings: Electronic device 500, processor 501, communication interface 502, memory 503, bus 504.

[0045] Reference Figure 1 A method for measuring the chest compression of a pedestrian in a collision, comprising:

[0046] Step S100, refer to Figure 2 Establish car and pedestrian models, specifically including:

[0047] Step S101: Create car models for both sedans and SUVs (Sport Utility Vehicles), specifically including:

[0048] Step S101-1: Select vehicle models and statistically analyze their exterior dimensions. In this embodiment, the 10 best-selling sedans and 10 best-selling SUVs are selected. The exterior dimensions of each vehicle model are plotted on the XZ coordinate system to obtain the median vehicle shape for both sedans and SUVs.

[0049] Step S101-2: Using Generic Vehicle Models (GVMs), the models of sedans and SUVs are obtained by adjusting the finite element mesh.

[0050] Step S102, establish a pedestrian model, specifically including:

[0051] Step S102-1: The pedestrian model adopts the THUMS V402 50th percentile model (a virtual human body model used for human collision simulation, which can provide detailed and accurate simulation data), and the pedestrian is in the TB024 standing posture (a posture used to define the posture of a pedestrian when walking, including the placement of the legs, arms and other parts, derived from Euro NCAP Technical Bulletin No. 24).

[0052] Step S102-2, refer to Figure 3 A chest band model (chest band 1 to chest band 6) was set on the outer side of the pedestrian model's chest cavity. The chest band model consisted of low-stiffness spring units connected to the ribs. Specifically, the chest band model was located at the horizontal positions of the 2nd, 4th, 6th, 8th, and 10th ribs and at the lower edge of the chest cavity. Rib deformation monitoring points were also defined to monitor the amount of chest deformation. (Refer to...) Figure 4 Rib deformation monitoring points were defined at 12.5%, 20%, 25%, 30%, 37.5%, 62.5%, 70%, 75%, 80%, and 87.5% of the center of the chest band, starting from the sternum and rotating counterclockwise. These points were named R1, R2, R3, R4, R5 and L1, L2, L3, L4, L5, respectively.

[0053] Step 200: Use the finite element general vehicle model and pedestrian model to establish a series of car-pedestrian collision response process simulation cases, including sedan-pedestrian collision response process and SUV-pedestrian response process. Each case has different car collision speed, hood height and hood angle.

[0054] Step S300, design a method for measuring chest compression, specifically including:

[0055] Step S301: Based on the method for measuring spinal compression, define a virtual spinal center at the same height as the chest girdle. Establish a spring element between the measurement point and the virtual vertebral center (refer to...). Figure 4 (As shown in the green unit in the image), the chest compression amount can be output through the deformation amount of the spring unit.

[0056] Step S302, relative to the method for measuring the compression of the chest band's virtual center, the virtual center of the chest band is defined by the average coordinates of four nodes at the back of the sternum and ribs. A spring measurement unit is established between the measurement point and the center of the chest band (refer to...). Figure 4 (As shown in the blue unit), the chest compression amount can be output through the deformation amount of the spring unit.

[0057] Step S303, the method for measuring the compression of the entire chest, involves establishing a transverse spring unit between the measurement point on the left and the corresponding point on the right (as shown in the reference). Figure 4(As shown in the black units in the diagram), such as L1 to R1 and L3 to R3, the chest compression amount can be output through the deformation amount of the spring unit.

[0058] Step S304. Method for measuring the hemiplegic compression of the chest relative to the sagittal plane, outputting the vertical displacement change of the measurement point relative to the sagittal plane of symmetry.

[0059] Step S400 involves performing a correlation analysis between chest compression and rib strain to obtain the chest compression measurement method that has the strongest correlation with chest injury. This includes:

[0060] Step S401: Obtain the rib fracture injury risk curve based on rib strain through experiments, including the first principal strain of the rib.

[0061] Step S402: Extract the maximum compression measured by various measurement methods at each measurement point on each chest band in each car-pedestrian collision response simulation case, and at the same time extract the maximum first principal strain of the cortical bone of each rib.

[0062] Step S403: Take the maximum chest compression measured at the k-th measurement point of the j-th compression measurement method for the i-th chest band in all simulation cases as data d. If the k-th measurement point of the i-th chest band is on rib m, take the maximum first principal strain of the cortical bone of the m-th rib in all simulation cases as data s.

[0063] The correlation coefficient between data d and data s is calculated using the following formula:

[0064]

[0065] In the formula, n represents the number of simulation cases in the collision response process. The correlation between the chest compression measured at the k-th measurement point of the i-th chest strap using the j-th method and the strain of the m-th rib is finally obtained. The correlation between each measurement point of each chest strap using various methods and the strain of the corresponding rib is then obtained.

[0066] Step S500: Select the chest compression measurement method and measurement point with the highest average correlation coefficient, specifically including:

[0067] Step S501: Calculate the average correlation coefficient of each measurement method, using the following formula:

[0068]

[0069] in, denoted as the number of correlation coefficients related to the j-th compression measurement method.

[0070] Compare each The method for measuring chest compression was selected based on the magnitude of the correlation coefficient, with the highest average value. This method was chosen as the final method for measuring chest compression.

[0071] Step S502: Calculate the average correlation coefficient of each measurement point, using the following formula:

[0072]

[0073] in, This represents the number of correlation coefficients associated with the k-th measurement point.

[0074] Compare each The chest compression measurement point with the largest average correlation coefficient was selected as the final chest compression measurement point.

[0075] This disclosure also provides a pedestrian chest impact compression measurement system, which utilizes a pedestrian chest impact compression measurement method from any of the above embodiments.

[0076] This disclosure also provides a storage medium storing a computer program that, when executed by a processor, can implement all the steps of a pedestrian chest impact compression measurement method in any of the above embodiments.

[0077] Those skilled in the art will understand that implementing all or part of the process in a method for measuring the compression of a pedestrian's chest during a collision can be accomplished by a computer program instructing related hardware. The program can be stored in a non-volatile computer-readable storage medium. When executed, the program can include the processes of various embodiments of the method for measuring the compression of a pedestrian's chest during a collision. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0078] This application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the steps of a pedestrian chest impact compression measurement method according to any of the above embodiments. In this application embodiment, the processor is the control center of the computer system; it can be a physical machine processor or a virtual machine processor.

[0079] Reference Figure 5 The electronic device 500 includes 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 for communication between these 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 is running, the processor 501 communicates with the memory 503 via the bus 504. When the machine-readable instructions are invoked by the processor 501, they execute the steps of a pedestrian chest impact compression measurement method as described in any of the above embodiments.

[0080] The above content is merely an embodiment of the present invention. Commonly known structures and characteristics of the solutions are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can improve and implement this solution based on the guidance provided in this application and their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for measuring the compression of a pedestrian's chest upon impact, characterized in that: include: Establish vehicle and pedestrian models; use the vehicle and pedestrian models to create a series of simulation cases of vehicle-pedestrian collision response processes; Design a method for measuring chest compression, and output the chest compression of each simulated case of collision response process; perform correlation analysis between the output chest compression and rib strain to obtain the chest compression measurement method that is most correlated with chest injury. The method and measurement points for measuring chest compression with the highest average correlation coefficient were selected. Correlation analysis was performed between the output chest compression and rib strain to obtain the chest compression measurement method that is most correlated with chest injury, including the following: In each car-pedestrian collision response simulation case, the maximum compression measured at each measurement point on each chest band using various measurement methods is extracted, and the maximum first principal strain of the cortical bone of each rib is also extracted. Take the maximum chest compression measured at the kth measurement point of the jth compression measurement method for the i-th chest band in all simulation cases as the data in the second column d. If the kth measurement point of the i-th chest band is on the m rib, take the maximum first principal strain of the cortical bone of the m-th rib in all simulation cases as the data in the first column s. The correlation coefficient between the data in column 1 and column 2 is calculated using the following formula: In the formula, n is the number of simulation cases of the collision response process, and finally the correlation between the chest compression measured at the k-th measurement point of the i-th chest strap using the j-th method and the strain of the m-th rib is obtained. The method for measuring chest compression with the highest average correlation coefficient was selected, including the following: The average correlation coefficient of each measurement method is calculated using the following formula: in, The number of correlation coefficients related to the j-th compression measurement method; Compare each The method for measuring chest compression was selected based on the magnitude of the correlation coefficient, with the highest average value. The chest compression measurement points with the highest average correlation coefficients were selected, including the following: The average correlation coefficient for each measurement point is calculated using the following formula: in, The number of correlation coefficients associated with the k-th measurement point; Compare each The chest compression measurement point with the largest average correlation coefficient was selected as the final chest compression measurement point.

2. The method for measuring pedestrian chest compression in a collision according to claim 1, characterized in that: Create a car model, including the following: Select vehicle models and statistically analyze their exterior dimensions. Plot the exterior dimensions of each vehicle model in the XZ coordinate system to obtain the median vehicle shape for sedans and SUVs. Models for sedans and SUVs were obtained by adjusting the finite element mesh of a general vehicle model using the finite element method.

3. The method for measuring pedestrian chest compression in a collision according to claim 1, characterized in that: The pedestrian model should include the following: The pedestrian model uses the THUMS V402 50th percentile model. A chest band model is set on the outside of the chest cavity of the pedestrian model. At the same time, several rib deformation monitoring points are defined counterclockwise around the center of the chest band from the sternum to detect the amount of chest deformation.

4. The method for measuring pedestrian chest compression in a collision according to claim 3, characterized in that: The chest band model is located at the level of the 2nd, 4th, 6th, 8th and 10th ribs and the lower edge of the thoracic cavity; monitoring points for rib deformation are defined at 12.5%, 20%, 25%, 30%, 37.5%, 62.5%, 70%, 75%, 80% and 87.5% of the center of the chest band, clockwise from the sternum.

5. The method for measuring pedestrian chest compression in a collision according to claim 2, characterized in that: The simulation cases of car-pedestrian collision response include sedan-pedestrian collision response and SUV-pedestrian collision response, with different car collision speeds, hood heights, and hood angles in each case.

6. The method for measuring pedestrian chest compression in a collision according to claim 1, characterized in that: Design a method for measuring chest compression, including the following: In contrast to the method for measuring spinal compression, a virtual spinal center is defined at the same height as the chest girder; a spring element is established between the measurement point and the virtual vertebral center, and the chest compression is output through the deformation of the spring element. Compared to the compression measurement method of the virtual center of the chest band, the virtual center of the chest band is defined by the average coordinates of four nodes at the back of the sternum and ribs. A spring measurement unit is established between the measurement point and the center of the chest band. The chest compression is output through the deformation of the spring unit. The method for measuring the compression of the entire chest involves establishing a transverse spring unit between the measurement point on the left and the corresponding point on the right, and the chest compression is output through the deformation of the spring unit. A method for measuring hemithoracic compression of the chest relative to the sagittal plane, outputting the vertical displacement change of the measurement point relative to the sagittal plane of symmetry.

7. A pedestrian chest impact compression measurement system, characterized in that: The method for measuring pedestrian chest compression during impact, as described in any one of claims 1-6, is employed.

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