A refined evaluation method and device for occupant damage in case of forced landing of a flying car at sea

Abstract

The present invention discloses a method and device for fine-grained evaluation of occupant damage during forced landing of a flying car at sea. The method comprises obtaining a flying car body model, a constraint model and a simple occupant model and assembling them, constructing a forced landing vehicle model, and performing a forced landing numerical simulation on the forced landing water area model, generating simple occupant damage evaluation data time by time step; when the simple occupant damage evaluation data of any time step exceeds the occupant part damage range, transmitting unit information at the current time step to automatically update the simple occupant model in the forced landing vehicle model by using a refined part model; continuing to perform the forced landing numerical simulation from the current time step until the forced landing numerical simulation is completed, and constructing a fine-grained evaluation result of occupant damage. Thus, the amount of data calculation in the forced landing simulation process at sea is reduced by automatically converting the hybrid occupant model, effectively realizing the fine-grained evaluation of occupant damage during forced landing of a flying car at sea, and providing a scientific basis for optimizing the structural design of the flying car and improving the safety protection of the occupants.

Description

Technical Field

[0001] The present invention relates to the technical field of biomechanical damage evaluation, and in particular to a method and device for fine-grained evaluation of damage to passengers of a flying car that makes an emergency landing at sea. Background Art

[0002] With the continuous development of the low-altitude economy, flying cars, as a new type of transportation for urban low-altitude intelligent transportation, three-dimensional intelligent transportation and future travel, are increasingly valued by the automotive and aviation fields, and have become an important development trend in the cross-border integration of the automotive and aviation technology industries.

[0003] In the actual working environment of flying across the sea, flying cars will inevitably encounter equipment failures, external impacts (such as bird strikes) and other emergencies, and be forced to make an emergency landing at sea. During the forced landing process, the flying car and the flow field of the forced landing sea area will have a violent fluid-solid coupling effect, causing the flying car to be subjected to the impact load of the seawater and transmit the load to the passengers on the car, which may cause serious injuries to the passengers.

[0004] However, current research in the field of flying cars mainly uses experimental and numerical simulation methods, and focuses on aspects such as appearance design and aerodynamic performance, while there is less research on aspects such as forced landing at sea, structural damage, and occupant injury. It is difficult to achieve a refined evaluation of occupant injuries when a flying car is forced to land at sea, and it is impossible to provide a scientific basis for optimizing the structural design of flying cars and improving the safety protection of occupants. Summary of the invention

[0005] The present invention provides a method and device for fine-grained evaluation of occupant damage during emergency landing of a flying car at sea, which solves a key problem existing in the field of existing flying car research: current research in the field of flying cars mainly adopts experimental and numerical simulation methods, and focuses on aspects such as appearance design and aerodynamic performance, but research on issues such as structural integrity and occupant safety during emergency landing of a flying car at sea is relatively lacking, which makes it difficult to accurately evaluate occupant damage, thereby affecting the optimization of structural design and the improvement of occupant safety protection measures.

[0006] The present invention provides a method for evaluating the injuries of passengers in a flying car forced landing at sea, comprising:

[0007] Obtain the flying vehicle model, constraint model and simple crew model and assemble them to build a forced landing vehicle model;

[0008] The forced landing vehicle model is used to perform forced landing numerical simulation on a pre-constructed forced landing water area model, and simple occupant injury evaluation data is generated time-step by time-step;

[0009] When the simple occupant injury evaluation data at any of the time steps exceeds the preset occupant part injury range, the simple occupant model in the forced landing vehicle model is updated using the refined part model at the current time step;

[0010] The forced landing numerical simulation continues to be executed from the current time step until the forced landing numerical simulation is completed, and a refined evaluation result of occupant injury is constructed.

[0011] Optionally, the obtaining and assembling of the flying vehicle body model, the constraint model and the simple occupant model to construct the forced landing vehicle model includes:

[0012] Get a simplified model of the flying car and a simple crew model;

[0013] Meshing the simplified model using shell elements to generate a flying vehicle body model;

[0014] Obtain the seat model and finite element seat belt model, and build the constraint model;

[0015] According to the preset contact conditions and component connection mode, the constraint model is used to constrain the simple occupant model into the flying vehicle model to obtain the forced landing vehicle model.

[0016] Optionally, the method further comprises:

[0017] In response to the triggering of the operation command, an initial sea area model is created using a hexahedral mesh;

[0018] Encrypt the hexahedral mesh of the forced landing location in the initial sea area model;

[0019] Taking the forced landing position as the center, the distribution density of the hexahedral grid is linearly reduced according to a preset gradient to generate a forced landing water area model.

[0020] Optionally, the forced landing vehicle model is used to perform forced landing numerical simulation on a pre-built forced landing water area model to generate simple occupant injury assessment data time by time, including:

[0021] Importing the forced landing vehicle model into the pre-built forced landing water area model, and setting the initial motion information of the forced landing vehicle model in response to the input initial water entry condition information;

[0022] Simulating the forced landing action of the forced landing vehicle model on the forced landing water area model, and calling the explicit finite element analysis algorithm to calculate the dynamic data corresponding to the simple occupant model step by step;

[0023] Simple occupant injury assessment data is generated based on the dynamics data at each time step.

[0024] Optionally, the dynamic data includes synthetic head acceleration, neck axial force, neck bending moment, lumbar compression load, chest pressure data and femoral axial load; generating simple occupant injury assessment data according to the dynamic data of each time step includes:

[0025] Calculating head injury assessment data according to the synthetic acceleration of the head at each time step;

[0026] Calculating neck injury evaluation data according to the neck axial force and neck bending moment at each time step;

[0027] The head injury assessment data, the neck injury assessment data, the lumbar compression load, the chest pressure data and the femoral axial load are used to construct simple occupant injury assessment data.

[0028] Optionally, the head injury assessment data is calculated using the following formula:

[0029]

[0030] in, For head injury assessment data, for The starting time when the value reaches the maximum value, is the end time when the HIC value reaches the maximum value, ( ) is the default value, is the resultant acceleration of the head at time step t.

[0031] Optionally, when the simple occupant injury assessment data at any time step exceeds a preset occupant part injury range, the refined part model is used to update the simple occupant model in the forced landing vehicle model at the current time step, including:

[0032] When the simple occupant injury assessment data of any of the time steps exceeds the preset occupant part injury range, locating the target part model to which the simple occupant injury assessment data belongs and splitting it;

[0033] Acquire unit information of the target part model, and select a refined initial part model matching the target part model from a preset high biological simulation pseudo-human model;

[0034] Using a linear interpolation method to transfer the unit information to the refined initial part model to obtain a refined part model;

[0035] The refined part model and the simplified occupant model excluding the target part model are connected at the current time step to update the forced landing vehicle model.

[0036] Optionally, the method further comprises:

[0037] When the forced landing vehicle model is automatically updated and the forced landing numerical simulation continues to be performed, the corresponding refined evaluation data is acquired time by time according to the part type to which the refined part model belongs;

[0038] The refined evaluation data and the simplified occupant injury evaluation data are matched according to the time step to generate a new occupant injury refined evaluation result.

[0039] Optionally, the method further comprises:

[0040] If the simple occupant injury assessment data of all the time steps do not exceed the preset occupant part injury range, then all the simple occupant injury assessment data are used to generate a refined occupant injury assessment result according to the time step.

[0041] The present invention also provides a device for finely evaluating injuries to passengers of a flying car that makes an emergency landing at sea, comprising:

[0042] The model acquisition module is used to acquire the flying vehicle model, the constraint model and the simple occupant model and assemble them to construct the forced landing vehicle model;

[0043] A forced landing simulation module, used to perform forced landing numerical simulation on a pre-built forced landing water area model using the forced landing vehicle model, and generate simple occupant injury evaluation data time by time;

[0044] A model updating module, configured to update the simple occupant model in the forced landing vehicle model using a refined part model at the current time step when the simple occupant injury evaluation data at any of the time steps exceeds a preset occupant part injury range;

[0045] The first evaluation result generating module is used to continue to execute the forced landing numerical simulation from the current time step until the forced landing numerical simulation is completed, and construct a refined evaluation result of occupant injury.

[0046] It can be seen from the above technical solutions that the present invention has the following advantages:

[0047] The flying vehicle model, constraint model and simple occupant model are obtained and assembled to construct the forced landing vehicle model; the forced landing vehicle model is used to perform the forced landing numerical simulation on the pre-constructed forced landing water model, and the simple occupant damage evaluation data is generated step by step; when the simple occupant damage evaluation data of any time step exceeds the preset occupant part damage range, the refined part model is used to automatically update the simple occupant model and transfer unit information in the current time step to update the forced landing vehicle model; the forced landing numerical simulation is continued from the current time step until the forced landing numerical simulation is completed, and the occupant damage refined evaluation results are constructed. Thus, the amount of data calculation in the forced landing simulation process at sea is reduced by the automatic conversion of the hybrid occupant model, and the refined evaluation of occupant damage of the flying car forced landing at sea is effectively realized, providing a scientific basis for optimizing the structural design of the flying car and improving the safety protection of the occupants. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0049] Figure 1 A flowchart of the steps of a method for fine-grained evaluation of injuries to passengers of a flying car that makes an emergency landing at sea provided by an embodiment of the present invention;

[0050] Figure 2 A schematic diagram of a construction process of a forced landing vehicle model provided by an embodiment of the present invention;

[0051] Figure 3 A schematic diagram of a finite element model of a human body in a sitting position provided by an embodiment of the present invention;

[0052] Figure 4 A schematic diagram of a simple occupant model updating process provided by an embodiment of the present invention;

[0053] Figure 5 A schematic diagram of a head refinement model provided by an embodiment of the present invention;

[0054] Figure 6 A schematic diagram of a neck refinement model provided by an embodiment of the present invention;

[0055] Figure 7 A schematic diagram of a refined chest model provided by an embodiment of the present invention;

[0056] Figure 8 A schematic diagram of a lower limb refined model provided by an embodiment of the present invention;

[0057] Fig. 9 A structural block diagram of a device for fine-grained evaluation of injuries to occupants of a flying car forced to land at sea provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0058] The embodiment of the present invention provides a method and device for fine-grained evaluation of occupant damage during an emergency landing of a flying car at sea, which solves a key problem existing in the field of existing flying car research: current research in the field of flying cars mainly adopts experimental and numerical simulation methods, and focuses on aspects such as appearance design and aerodynamic performance, but research on issues such as structural integrity and occupant safety during emergency landing of a flying car at sea is relatively lacking, which makes it difficult to accurately evaluate occupant damage, thereby affecting the optimization of structural design and the improvement of occupant safety protection measures.

[0059] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] See also Figure 1 , Figure 1 A flowchart of the steps of a method for fine-grained evaluation of occupant injuries in a flying car forced landing at sea provided in an embodiment of the present invention.

[0061] The present invention provides a method for evaluating the injuries of passengers in a flying car forced landing at sea, comprising:

[0062] Step 101, obtaining a flying vehicle body model, a constraint model and a simple occupant model and assembling them to construct an emergency landing vehicle model;

[0063] The flying car body model refers to a simplified model generated by finite element pre-processing software after further simplifying the CAD simplified model of the flying car. It is a simplified model used to characterize the flying car structure.

[0064] A simple occupant model refers to a simple dummy occupant model, which is mainly composed of the head, neck, trunk, pelvis and limbs, and can simply reflect the biomechanical response of the human body, such as the HybridIII 50th percentile male finite element dummy model.

[0065] The constraint model refers to a simple model used to simulate the position constraints of the seat belt and the seat on the simple occupant model, which includes the seat belt model and the seat model.

[0066] The forced landing vehicle model refers to a finite element model of the occupant-restraint system-flying car constructed by assembling a passenger model, a seat model, a seat belt model and a rigid body model of the flying car shell, so as to simulate the normal posture of the occupants of the flying car during driving.

[0067] In the embodiment of the present invention, by responding to the damage assessment request input externally, the flying vehicle model, constraint model and simple occupant model are obtained from the finite element pre-processing software to obtain the model data basis for the subsequent fine damage assessment. After obtaining various models, they are assembled according to their connection relationship and contact conditions to construct the forced landing vehicle model.

[0068] In an example of the present invention, step 101 may include the following sub-steps:

[0069] Get a simplified model of the flying car and a simple crew model;

[0070] The simplified model is meshed using shell elements to generate a flying vehicle model;

[0071] Obtain the seat model and finite element seat belt model, and build the constraint model;

[0072] According to the preset contact conditions and component connection methods, the constraint model is used to constrain the simple occupant model to the flying vehicle model to obtain the forced landing vehicle model.

[0073] In this embodiment, for a certain type of flying car, a simplified CAD model of the flying car is constructed using Solidworks software. Because the structure of the flying car is complex, in order to simplify the structural model of the flying car and reduce the amount of calculation, its internal structure such as seats, seat belts, etc. is not considered. By importing the CAD model of the flying car into the finite element pre-processing software for model construction, a simplified model that can characterize the structure of the flying car is generated. The structural components of the flying car are all treated as shell elements. Although the structure of the flying car is complex and the material properties of different parts are not the same, in this embodiment, considering the situation that the flying car adopts a low-speed forced landing, the deformation of the flying car structure is not considered in the whole process. The finite element model of the flying car is defined as a rigid body, and the mass, center of gravity and moment of inertia of the flying car are defined at the same time. Since the simplified model of the flying car shell is composed of faces, the shell element is used for meshing to generate the flying car body model.

[0074] It should be noted that when dividing the mesh, both reasonable calculation time and accuracy requirements of the calculation should be considered. Therefore, in the area where the stress of the model boundary is concentrated, different specifications can be set to make some units smaller; in the area with smaller stress gradient, larger units and low-level units of another specification can be used. The vast majority of units in the entire body structure use quadrilateral shell units, supplemented by a small number of triangular shell units at locations such as arcs and chamfer transitions for connection and transition, so as to generate a flying body model that takes into account both calculation time and accuracy requirements.

[0075] In this embodiment, the constraint model includes two parts: a seat model and a seat belt model. The seat model consists of a seat support plate, a seat cushion, a seat back, a frame and other structures, wherein the seat cushion is connected to the bottom of the flying car through a movable hinge, the seat cushion and the seat back are simulated using hexahedral elements, and the frame and support plates are simulated using triangular and quadrilateral shell elements. The finite element seat belt is mainly composed of one-dimensional elements and two-dimensional elements, wherein the one-dimensional element is used to simulate the fixation of the seat belt and the anchor point, and the two-dimensional element is used to simulate the interaction between the seat belt and the passenger dummy.

[0076] For example, you can use the MAT_SEATBELT keyword in the LS-DYNA software to simulate the fixation situation, assign the material to MAT_ELASTIC, select Seatbelt Fitting in the Safety module in the LS-PrePost software to create seatbelts for the chest and abdomen of the occupant, select the chest and abdomen as the contact surfaces, and select the Mixed command in Seatbelt Fitting to create the two-dimensional unit part of the finite element seatbelt.

[0077] like Figure 2 As shown, Figure 2 A schematic diagram of a construction process of an emergency landing vehicle model in an embodiment of the present invention is shown.

[0078] In this embodiment, a relatively simple finite element dummy model is selected as a simple occupant model, such as a finite element dummy model of a Hybrid III 50th percentile male. After obtaining the flying car CAD model, it is geometrically simplified and divided into shell unit grids to construct a flying car shell rigid body model as a flying car body model. By setting the component connection mode and contact conditions, the simple occupant model is constrained by the seat belt model, and the seat belt model is further constrained by the seat model. At the same time, the simple occupant model and the seat model are in contact according to the contact conditions, and the constrained seat model is fixedly installed in the flying car body model, thereby realizing the assembly between the models to construct the occupant-restraint system-flying car model as the forced landing vehicle model.

[0079] The contact includes the surface contact between the simple occupant model and the seat model, the surface contact between the simple occupant model and the seat belt model, and the self-contact of each component. The seat model itself pre-presses the simple occupant model and the seat model to make the two fit tightly and without penetration.

[0080] In one example of the present invention, the method further comprises the following steps:

[0081] In response to the triggering of the operation command, an initial sea area model is created using a hexahedral mesh;

[0082] Encrypt the hexahedral mesh of the forced landing location in the initial sea area model;

[0083] Taking the forced landing location as the center, the distribution density of the hexahedral grid is linearly reduced according to the preset gradient to generate the forced landing water area model.

[0084] The forced landing water area model refers to the model of the sea area and air area when simulating the forced landing of a flying car in the sea area. By defining media such as water and air, and using hexahedral meshes to construct the initial sea area model, the local mesh is further encrypted where it may be coupled with the bottom of the vehicle body. The water body mesh is gradually coarsened according to a certain gradient using linear distribution meshes before and after the forced landing position of the flying car to reduce the distribution density of the hexahedral meshes, and the forced landing water area model is obtained.

[0085] For example, the materials of the forced landing water area and air domain in the forced landing water area model can be defined by the two keywords MAT_NULL and EOS_GRUNEISEN in the LS-DYNA software. When the arbitrary Lagrange-Euler (ALE) method is used to analyze the forced landing of a flying car at sea, the SECTION_SOLID_ALE keyword is used to define media such as water and air.

[0086] It should be noted that since the water area is much larger than the size of the flying car, the forced landing sea area can be considered as an infinite sea area, and the boundary area between the sea area and the air area is defined as a non-reflection boundary (excluding their common boundary). This can avoid the reflection of the boundary layer during the downward propagation of water pressure when the flying car makes an emergency landing.

[0087] Step 102, using the forced landing vehicle model to perform forced landing numerical simulation on the pre-built forced landing water area model, and generating simple occupant injury assessment data time by time;

[0088] After completing the creation of the forced landing water area model and the forced landing vehicle model, the forced landing vehicle model can be imported into the pre-processing software such as LS-PrePost, and the initial water entry condition information can be set. The forced landing vehicle model can be simulated on the forced landing water area model in a numerical simulation manner to perform a forced landing at sea. At the same time, the explicit finite element analysis method is used to simulate the dynamic response and load transfer process of the flying car in the forced landing accident at sea, and the simple occupant injury evaluation data generated time by time when the flying car collides with the seawater is obtained.

[0089] Among them, simple occupant injury evaluation data refers to data used to evaluate the injuries of various parts of the simple occupant model during the forced landing at sea, including but not limited to head injury evaluation data, neck injury evaluation data, lumbar injury evaluation data, chest injury evaluation data and thigh injury evaluation data.

[0090] In an example of the present invention, step 102 may include the following sub-steps S11-S13:

[0091] S11, importing the forced landing vehicle model into the pre-built forced landing water area model, and setting the initial motion information of the forced landing vehicle model in response to the input initial water entry condition information;

[0092] In this embodiment, the forced landing vehicle model is imported into a pre-built forced landing water area model, which can be run in LS-PrePost, and at the same time respond to external inputs such as user input, upstream information input, etc., to obtain initial water entry condition information, and set the initial motion information of the forced landing vehicle model according to the initial water entry condition information.

[0093] It should be noted that the initial water entry condition information refers to the various motion parameters of the forced landing vehicle model when the forced landing water area model performs forced landing simulation, which can be used to set the initial motion information of the forced landing vehicle model. The initial motion information includes but is not limited to the horizontal speed, initial vertical descent speed and initial attitude angle of the forced landing vehicle model, and the initial water entry condition information can be determined based on the data information collected by the flying vehicle in the actual forced landing situation or based on model speculation.

[0094] S12, simulating the forced landing action of the forced landing vehicle model on the forced landing water area model, and calling the explicit finite element analysis algorithm to calculate the dynamic data corresponding to the simple occupant model step by step;

[0095] The dynamic data refers to the data that characterizes the dynamic response and load transfer process of the simple occupant model in the forced landing vehicle model during the forced landing action.

[0096] The time step refers to the time period in which the forced landing vehicle model is divided according to certain intervals from the start time to the end time of the forced landing numerical simulation.

[0097] In this embodiment, after completing the setting of the initial motion information of the forced landing vehicle model, the forced landing action of the forced landing vehicle model is simulated on the forced landing water area model time by time based on the position, angle and speed of the initial motion information, and at the same time, the explicit finite element analysis algorithm is called to simulate its dynamic response and load transfer process, so as to calculate the dynamic data of the simple occupant model time by time.

[0098] S13. Generate simple occupant injury assessment data based on the dynamic data of each time step.

[0099] Further, the dynamic data includes the synthetic acceleration of the head, the axial force of the neck, the bending moment of the neck, the lumbar compression load, the chest pressure data and the femoral axial load; S13 may include the following sub-steps:

[0100] Calculate the head injury assessment data based on the synthetic acceleration of the head at each time step;

[0101] Calculate the neck injury evaluation data based on the neck axial force and neck bending moment at each time step;

[0102] Simple occupant injury assessment data are constructed using head injury assessment data, neck injury assessment data, lumbar compression load, chest pressure data and femoral axial load.

[0103] In this embodiment, after the dynamic data corresponding to the simple occupant model at each time step is obtained, the simple occupant injury assessment data can be calculated and generated time step by time according to the dynamic data.

[0104] Optionally, the head injury assessment data is calculated using the following formula:

[0105]

[0106] in, For head injury assessment data, for The starting time when the value reaches the maximum value, is the end time when the HIC value reaches the maximum value, ( ) is the default value, is the composite acceleration of the head at time step t, specifically linear acceleration, in units of gravitational acceleration g. The HIC value is affected by the time interval, ( ) is generally 36ms and 15ms. In this embodiment, the HIC value can be HIC with an interval of 36ms. 36 Carry out occupant head injury analysis, such as C-NCAP driver injury threshold regulation HIC 36 is (650,1000), when HIC 36When the value exceeds 1000, it means that the head has been subjected to a large impact force, which may cause head injury.

[0107] At the same time, the Neck Injury Criteria combines the axial force and bending moment of the dummy's neck to evaluate the neck injury. The load and bending moment of the neck at each moment during the collision are standardized according to the corresponding critical intercept value, so as to linearly synthesize the axial force and bending moment of the neck, and calculate the neck injury evaluation data according to the axial force and bending moment of the neck at each time step. The specific calculation process is as follows:

[0108]

[0109] Among them, F Z and M Y Denote the axial force and bending moment of the neck, F int and M int is the corresponding critical intercept value, as shown in Table 1 below:

[0110] ;

[0111] Table 1

[0112] Among them, F int is the tensile or compressive critical intercept value, corresponding to the values ​​in the first and second columns of the table. Z (Axial force on the neck) manifests itself as a tensile force, F int is the corresponding tensile critical intercept value, and vice versa; M int is the critical intercept value of the front and rear bending of the neck. Y When it is manifested as forward bending moment, M int is the corresponding forward bending critical intercept value, and vice versa

[0113] It should be noted that at any time during the forced landing at sea, The value cannot be greater than 1. If it is greater than 1, it indicates that the occupant's neck is injured.

[0114] For the lumbar compression load, chest pressure data and femoral axial load, their values ​​can be directly used as part of the simple occupant injury evaluation data. Combined with the calculation, the head injury evaluation data and the neck injury evaluation data are obtained to construct the simple occupant injury evaluation data.

[0115] Among them, the lumbar compression load As the lumbar injury evaluation data, it is stipulated in the 23.562 clause of CCAR-23R3 that the airworthiness of the aircraft requires that the compression load of the lumbar spine and pelvis cannot be greater than 6680 N. Therefore, during the forced landing of the flying car at sea, the occupant's lumbar compression load is required to be ≤6680 N.

[0116] The chest pressure data is used as chest injury evaluation data. During the forced landing of a flying car, the chest will be restrained by the seat belt, which poses a greater risk of injury. The chest pressure data such as the acceleration a2 at the center of gravity of the chest and the chest compression D are used to preliminarily reflect the degree of damage to the chest. The continuous action time of the linear acceleration exceeding 60g at the center of gravity of the chest shall not exceed 3ms. The chest compression, that is, the maximum compression between the dummy's torso and ribs, shall not exceed 50mm.

[0117] Femoral axial load is used as thigh injury evaluation data. During the forced landing of a flying car at sea, the lower limbs are the area with a high frequency of multiple contusions. The thigh injury of the occupant is evaluated by using the thigh axial compression force, that is, the femoral axial load, as the thigh injury criterion FFC (Femur Force Criteria). FMVSS208 and ECE R94 stipulate that this value shall not exceed 10 KN, but in the new car evaluation program C-NCAP, the score range of this value is (3.8 KN, 9.07 KN).

[0118] Step 103, when the simple occupant injury evaluation data at any time step exceeds the preset occupant part injury range, the refined part model is used to update the simple occupant model in the forced landing vehicle model at the current time step;

[0119] The refined part model refers to the simulation model corresponding to each human tissue, organ or part in the human finite element model with high bio-simulation. The human finite element model with high bio-simulation includes fine human tissue, organ, and anatomical structure features, which can provide more realistic material properties and obtain more realistic collision data. It can obtain more realistic injury evaluation in occupant injury simulation analysis, such as intracranial hemorrhage, concussion, bone fracture, body organ injury, joint slippage, ligament tear, etc. Figure 3 As shown, it shows a finite element model of the human body in a sitting state. Through human CT scanning, the human body structure is accurately modeled, and the tissues, organs and systems are closer to the human body.

[0120] The human finite element computational model with high bio-similarity can be used to systematically analyze the human body's injuries, but due to the complexity of modeling, high requirements for model accuracy, long construction period and slow calculation speed, the simple dummy parts that need further detailed evaluation can be replaced with the corresponding parts of the high bio-similarity finite element human model to update the simple occupant model, thereby updating the forced landing vehicle model to achieve high-precision evaluation of the degree of injury to vulnerable parts.

[0121] In an example of the present invention, step 103 may include the following sub-steps:

[0122] When the simple occupant injury assessment data at any time step exceeds the preset occupant part injury range, the target part model to which the simple occupant injury assessment data belongs is located and split;

[0123] Acquire unit information of the target part model, and select a refined initial part model matching the target part model from a preset high biological simulation pseudo-human model;

[0124] The unit information is transferred to the refined initial part model by using a linear interpolation method to obtain a refined part model;

[0125] At the current time step, the refined part model and the simplified occupant model except the target part model are connected to update the forced landing vehicle model.

[0126] The occupant injury range refers to the predetermined proportion of the numerical range corresponding to each part of the simple occupant model, such as 60%. For example, the numerical range of the head injury evaluation data is (650, 1000), the numerical range of the neck injury evaluation data can refer to Table 1, the numerical range of the lumbar compression load is less than 6680N, and the numerical range of the chest pressure data is that the linear acceleration at the center of gravity of the chest exceeds 60g and the continuous action time shall not exceed 3ms. The chest compression, that is, the maximum compression between the dummy torso and the ribs shall not exceed 50mm, and the numerical range of the femoral axial load is (3.8KN, 9.07KN).

[0127] In this embodiment, when the simple occupant injury assessment data at any time step exceeds the preset occupant part injury range, the forced landing numerical simulation is suspended, and the target part model to which the simple occupant injury assessment data exceeding the occupant part injury range belongs is located and split to obtain the target part model and the simple occupant model other than the target part model. That is, in the numerical simulation solution process of the forced landing of the flying car at sea, the HIC solved at each time step is 36 、N ij 、F L , a2, D, F F When a certain result reaches 60% of the set occupant injury index, that is, exceeds the occupant part injury range, the unit information of the target part model is obtained, and the refined part initial model matching the target part model is selected from the preset high bio-simulation pseudo-human model, and the unit information is used as the known information for linear interpolation to transfer the unit information to the refined part initial model to obtain the refined part model, and the refined part model and the simple occupant model except the target part model are connected to update the forced landing vehicle model.

[0128] In addition, the update time of the simple occupant model can be determined based on the simple occupant damage evaluation data of each part model at each time step, and the number of updates is not limited.

[0129] like Figure 4 As shown, Figure 4 A schematic diagram of a simple occupant model updating process in an embodiment of the present invention is shown.

[0130] Taking the head hybrid model as an example (as shown in the figure below), the splitting of the finite element dummy model includes the splitting of the finite element body nodes, the splitting of the finite element body surface and the splitting of the body element. 36 、N ij 、F L , a2, D, F F When a result reaches 60% of the set occupant injury index, that is, exceeds the occupant part injury range, the corresponding part model of the constructed high biosimulation human body model is used to replace the corresponding part of the original simple occupant model. By redefining the local finite element models obtained by splitting, a standard connection interface is obtained. At the same time, through the linear interpolation method, the unit information of the replaced part model of the simple dummy at this step (the stress of the Gaussian integral point in each unit and the displacement, velocity and acceleration of the finite element node) is transferred to the corresponding refined initial part model, thereby realizing the update of the simple occupant model, and then continue to solve the numerical simulation process until the numerical simulation solution is completed.

[0131] Step 104, continue to execute the forced landing numerical simulation from the current time step until the forced landing numerical simulation is completed, and construct a refined evaluation result of occupant damage.

[0132] In this embodiment, after the update of the forced landing vehicle model is completed, the simulation operation of the forced landing numerical simulation is continued from the current time step until the numerical simulation of all time steps is completed. At this time, the forced landing numerical simulation results generate simple occupant injury evaluation data and / or refined evaluation data for each time step. Finally, all the simple occupant injury evaluation data and / or refined evaluation data are used and sorted with the time step as the sorting unit, thereby completing the construction of the occupant injury refined evaluation results.

[0133] The refined evaluation results of occupant injuries may be presented in the form of a table, a tree diagram, a line graph, etc., and the embodiment of the present invention does not impose any limitation on this.

[0134] In one example of the present invention, the method further comprises the following steps:

[0135] When the forced landing vehicle model is automatically updated and the forced landing numerical simulation continues to be performed, the corresponding refined evaluation data is obtained step by step according to the part type to which the refined part model belongs;

[0136] According to the time-step matching of the refined evaluation data and the simple occupant injury evaluation data, a new refined occupant injury evaluation result is generated.

[0137] In this embodiment, in order to further obtain more refined simple occupant injury assessment data, when the forced landing vehicle model is automatically updated and the forced landing numerical simulation continues to be performed, the refined assessment data corresponding to the refined part model is obtained step by step from the current time step according to the part type to which the refined part model belongs. After completing the forced landing numerical simulation of all time steps, the refined assessment data and the simple occupant injury assessment data are matched according to the time step to generate a new occupant injury refined assessment result. Among them, the refined part model can include but is not limited to the head refined model, the neck refined model, the chest refined model and the lower limb refined model.

[0138] For example, see Figure 5 In traffic accidents, the head is a part that is more easily injured and is closely related to human life safety. The human head has a complex structure, including skull, brain tissue and other structures. Human head injuries are mainly skull fractures and brain tissue damage. During the forced landing of a flying car at sea, the head may collide with components such as seats and airbags, causing skull or facial bone fractures, which in turn lead to brain tissue damage such as contusions, lacerations, and concussions. In addition, studies on head injuries in traffic accidents have shown that when the intracranial pressure is between 56KPa and 173KPa, it will cause moderate brain damage, and when the skull stress exceeds 10MPa, there is a risk of fracture. To this end, while obtaining the simple occupant injury evaluation data, if the part type of the refined part model is the head, the intracranial pressure and skull stress can be obtained as refined evaluation data, and new data items are created at the corresponding time step and combined with the existing occupant evaluation data to generate new occupant injury refined evaluation results.

[0139] See also Figure 6 During the forced landing of a flying car, the neck mainly analyzes whether there is a risk of injury to the cervical spine. During the forced landing, the lateral impact force of the seat belt shoulder strap on the occupant's neck and the force generated by inertia cause the cervical spine to bear a greater risk of injury. In the finite element analysis of human cervical spine injury in traffic accidents, it was pointed out that the yield strength of the outer cortical bone of the human cervical spine is 236MPa, and the yield strength of the inner cancellous bone is 59MPa. The compressive stress tolerance limit of the intervertebral disc is 11MPa, and the tensile stress tolerance limit is 3MPa. Similarly, if the part type to which the refined part model belongs is the neck, the above data can be obtained as refined evaluation data and incorporated into the refined evaluation result of the occupant injury at this time step.

[0140] See also Figure 7The human chest consists of the thorax and internal organs and tissues. The entire thorax is a highly strong and deformable protective cover composed of 12 pairs of ribs, which protects the heart, left and right lungs, aorta and other organs. Chest injuries are also relatively dangerous and complicated in various traffic accidents. During the forced landing of a flying car at sea, due to the restraint effect of the seat belt, a huge impact load is generally generated on the chest, causing sternum or rib fractures, and then the heart and thoracic aorta may be injured; in addition, it is possible that internal organs may be damaged due to inertial loads. The evaluation indicators of human chest injury are as follows: the yield stress of human rib cortical bone is 88MPa, the pressure limit of the lungs is 16Kpa, the pressure limit of the heart is 170KPa, and the pressure limit of the liver is 251KPa. The THUMS human chest model can directly evaluate the chest injury of the occupant during the forced landing process through the stress and strain of the chest. Similarly, if the part type of the refined part model is chest, the above data can be obtained as refined evaluation data and incorporated into the refined evaluation result of the occupant injury at this time step.

[0141] See also Figure 8 , the lower limbs of the human body are mainly composed of thighs, knees, calves, ankles and feet. Although injuries to the lower limbs generally do not cause life-threatening dangers, they can have a serious impact on people's daily lives. During the forced landing of a flying car, the injuries to the lower limbs of the occupants mainly include femoral fractures, tibia fractures and knee joint injuries. Most femoral and tibia fractures are caused by direct and indirect loads on the legs. For example, collisions with the dashboard, deformation of the cab structure, etc. The axial force load range of the thigh femur is (3.8 KN, 9.07 KN), the axial force of the dummy tibia shall not exceed 8 KN, and the maximum slippage of the dummy knee joint shall not exceed 15 mm. Similarly, if the part type to which the refined part model belongs is the lower limb, the above data can be obtained as refined evaluation data and incorporated into the refined evaluation results of the occupant injury at that time step.

[0142] In another example of the present invention, the method further comprises the following steps:

[0143] If the simple occupant injury assessment data of all time steps do not exceed the preset occupant part injury range, all the simple occupant injury assessment data are used to generate the occupant injury refined assessment results according to the time step.

[0144] In this embodiment, if the simple occupant injury assessment data of all time steps do not exceed the preset occupant part injury range, it means that during the current simulation, the various protection measures for forced landing at sea can meet the needs. At this time, all the simple occupant injury assessment data can be used in the order of time steps to generate a refined occupant injury assessment result.

[0145] In the embodiment of the present invention, the flying vehicle body model, the constraint model and the simple occupant model are obtained and assembled to construct the forced landing vehicle model; the forced landing vehicle model is used to perform the forced landing numerical simulation on the pre-constructed forced landing water area model, and the simple occupant injury evaluation data is generated step by step; when the simple occupant injury evaluation data of any time step exceeds the preset occupant part injury range, the simple occupant model is automatically updated by the refined part model in the current time step to complete the update of the forced landing vehicle model; the forced landing numerical simulation is continued from the current time step until the forced landing numerical simulation is completed, and the occupant injury refined evaluation result is constructed. Thus, the amount of data calculation in the forced landing simulation process at sea is reduced by model replacement, and the refined occupant injury evaluation can be realized in a single forced landing simulation process at sea, effectively reducing the calculation cost of the refined evaluation of occupant injury of the flying car forced landing at sea, and providing a scientific basis for optimizing the structural design of the flying car and improving the safety protection of the occupants.

[0146] See also Fig. 9 , Fig. 9 A structural block diagram of a device for fine-grained evaluation of injuries to passengers of a flying car forced to land at sea in an embodiment of the present invention is shown.

[0147] The present invention also provides a device for finely evaluating injuries to passengers of a flying car that makes an emergency landing at sea, comprising:

[0148] The model acquisition module 901 is used to acquire the flying vehicle model, the constraint model and the simple occupant model and assemble them to construct the forced landing vehicle model;

[0149] The forced landing simulation module 902 is used to perform forced landing numerical simulation on a pre-built forced landing water area model using a forced landing vehicle model, and generate simple occupant injury evaluation data time by time step;

[0150] The model updating module 903 is used to update the simple occupant model in the forced landing vehicle model using the refined part model at the current time step when the simple occupant injury evaluation data at any time step exceeds the preset occupant part injury range;

[0151] The first evaluation result generating module 904 is used to continue to execute the forced landing numerical simulation from the current time step until the forced landing numerical simulation is completed, and construct a refined evaluation result of occupant damage.

[0152] Optionally, the model acquisition module 901 is specifically used for:

[0153] Get a simplified model of the flying car and a simple crew model;

[0154] The simplified model is meshed using shell elements to generate a flying vehicle model;

[0155] Obtain the seat model and finite element seat belt model, and build the constraint model;

[0156] According to the preset contact conditions and component connection methods, the constraint model is used to constrain the simple occupant model to the flying vehicle model to obtain the forced landing vehicle model.

[0157] Optionally, the device further comprises:

[0158] A sea area model creation module is used to respond to the triggering of the operation command and use a hexahedral mesh to create an initial sea area model;

[0159] A mesh encryption module is used to encrypt the hexahedral mesh of the forced landing location in the initial sea area model;

[0160] The grid density adjustment module is used to linearly reduce the distribution density of the hexahedral grid according to a preset gradient with the forced landing location as the center to generate a forced landing water area model.

[0161] Optionally, the forced landing simulation module 902 includes:

[0162] An initialization setting module is used to import the forced landing vehicle model into the pre-built forced landing water area model, and respond to the input initial water entry condition information to set the initial motion information of the forced landing vehicle model;

[0163] The dynamics data calculation module is used to simulate the forced landing action of the forced landing vehicle model on the forced landing water model, and call the explicit finite element analysis algorithm to calculate the dynamics data corresponding to the simple occupant model step by step;

[0164] The simple occupant injury assessment data generation module is used to generate simple occupant injury assessment data based on the dynamic data of each time step.

[0165] Optionally, the dynamic data includes head composite acceleration, neck axial force, neck bending moment, lumbar compression load, chest pressure data and femoral axial load; the simple occupant injury assessment data generation module is specifically used for:

[0166] Calculate the head injury assessment data based on the synthetic acceleration of the head at each time step;

[0167] Calculate the neck injury evaluation data based on the neck axial force and neck bending moment at each time step;

[0168] Simple occupant injury assessment data are constructed using head injury assessment data, neck injury assessment data, lumbar compression load, chest pressure data and femoral axial load.

[0169] Optionally, the head injury assessment data is calculated using the following formula:

[0170]

[0171] in, For head injury assessment data, for The starting time when the value reaches the maximum value, is the end time when the HIC value reaches the maximum value, ( ) is the default value, is the resultant acceleration of the head at time step t.

[0172] Optionally, the model updating module 903 is specifically used for:

[0173] When the simple occupant injury assessment data at any time step exceeds the preset occupant part injury range, the target part model to which the simple occupant injury assessment data belongs is located and split;

[0174] Acquire unit information of the target part model, and select a refined initial part model matching the target part model from a preset high biological simulation pseudo-human model;

[0175] The unit information is transferred to the refined initial part model by using a linear interpolation method to obtain a refined part model;

[0176] At the current time step, the refined part model and the simplified occupant model except the target part model are connected to update the forced landing vehicle model.

[0177] Optionally, the device further comprises:

[0178] A refined evaluation data acquisition module is used to acquire the corresponding refined evaluation data step by step according to the part type to which the refined part model belongs when the forced landing vehicle model is automatically updated and the forced landing numerical simulation continues to be performed;

[0179] The evaluation result updating module is used to generate new occupant injury refined evaluation results by matching the refined evaluation data and the simple occupant injury evaluation data according to the time step.

[0180] Optionally, the device further comprises:

[0181] The second evaluation result generating module is used to generate a refined evaluation result of occupant injury according to the time step using all the simple occupant injury evaluation data if the simple occupant injury evaluation data of all time steps do not exceed the preset occupant part injury range.

[0182] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described devices and modules can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0183] In the several embodiments provided by the present invention, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the modules is only a logical function division. There may be other division methods in actual implementation, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0184] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed on multiple network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0185] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A refined evaluation method for occupant damage in case of forced landing of a flying car at sea, characterized in that: include: Obtain the flying vehicle model, constraint model and simple crew model and assemble them to build a forced landing vehicle model; The forced landing vehicle model is used to perform forced landing numerical simulation on a pre-constructed forced landing water area model, and simple occupant injury evaluation data is generated time-step by time-step; When the simple occupant injury evaluation data at any of the time steps exceeds the preset occupant part injury range, the simple occupant model in the forced landing vehicle model is automatically updated using the refined part model at the current time step; Continuing to execute the forced landing numerical simulation from the current time step until the forced landing numerical simulation is completed, and constructing a refined evaluation result of occupant damage; When the simple occupant injury evaluation data at any time step exceeds the preset occupant part injury range, the simple occupant model in the forced landing vehicle model is automatically updated using the refined part model at the current time step, including: When the simple occupant injury assessment data of any of the time steps exceeds a preset occupant part injury range, locating the target part model to which the simple occupant injury assessment data belongs and splitting it; the occupant part injury range refers to a predetermined proportion value of the numerical range corresponding to each part of the simple occupant model; Acquire unit information of the target part model, and select a refined initial part model matching the target part model from a preset high biological simulation pseudo-human model; Using a linear interpolation method to transfer the unit information to the refined initial part model to obtain a refined part model; The refined part model and the simplified occupant model other than the target part model are connected at the current time step to automatically update the forced landing vehicle model.

2. The method according to claim 1, characterized in that The method of obtaining the flying vehicle body model, the constraint model and the simple occupant model and assembling them to construct the forced landing vehicle model includes: Get a simplified model of the flying car and a simple crew model; Meshing the simplified model using shell elements to generate a flying vehicle body model; Obtain the seat model and finite element seat belt model, and build the constraint model; According to the preset contact conditions and component connection mode, the constraint model is used to constrain the simple occupant model into the flying vehicle model to obtain the forced landing vehicle model.

3. The method according to claim 1, characterized in that The method further comprises: In response to the triggering of the operation command, an initial sea area model is created using a hexahedral mesh; Encrypt the hexahedral mesh of the forced landing location in the initial sea area model; Taking the forced landing position as the center, the distribution density of the hexahedral grid is linearly reduced according to a preset gradient to generate a forced landing water area model.

4. The method according to claim 1, characterized in that: The forced landing vehicle model is used to perform forced landing numerical simulation on a pre-built forced landing water area model, and simple occupant injury evaluation data is generated time by time, including: Importing the forced landing vehicle model into the pre-built forced landing water area model, and setting the initial motion information of the forced landing vehicle model in response to the input initial water entry condition information; Simulating the forced landing action of the forced landing vehicle model on the forced landing water area model, and calling the explicit finite element analysis algorithm to calculate the dynamic data corresponding to the simple occupant model step by step; Simple occupant injury assessment data is generated based on the dynamics data at each time step.

5. The method according to claim 4, characterized in that The dynamic data includes synthetic head acceleration, neck axial force, neck bending moment, lumbar compression load, chest pressure data and femoral axial load; the simple occupant injury assessment data is generated according to the dynamic data of each time step, including: Calculating head injury assessment data according to the synthetic acceleration of the head at each time step; Calculating neck injury evaluation data according to the neck axial force and the neck bending moment at each time step; The head injury assessment data, the neck injury assessment data, the lumbar compression load, the chest pressure data and the femoral axial load are used to construct simple occupant injury assessment data.

6. The method according to claim 5, characterized in that The head injury evaluation data is calculated by the following formula: Wherein, HIC is the head injury evaluation data, t1 is the starting time when the HIC value reaches the maximum value, t2 is the ending time when the HIC value reaches the maximum value, (t2-t1) is the preset value, and a(t) is the composite acceleration of the head at time step t.

7. The method according to claim 1, characterized in that The method further comprises: When the forced landing vehicle model is automatically updated and the forced landing numerical simulation continues to be performed, the corresponding refined evaluation data is acquired time by time according to the part type to which the refined part model belongs; The refined evaluation data and the simplified occupant injury evaluation data are matched according to the time step to generate a new occupant injury refined evaluation result.

8. The method according to claim 1, characterized in that The method further comprises: If the simple occupant injury assessment data of all the time steps do not exceed the preset occupant part injury range, then all the simple occupant injury assessment data are used to generate a refined occupant injury assessment result according to the time step.

9. A device for evaluating the injuries of passengers in a flying car forced landing at sea, characterized in that: include: The model acquisition module is used to acquire the flying vehicle model, the constraint model and the simple occupant model and assemble them to construct the forced landing vehicle model; A forced landing simulation module, used to perform forced landing numerical simulation on a pre-built forced landing water area model using the forced landing vehicle model, and generate simple occupant injury evaluation data time by time; A model updating module, configured to update the simple occupant model in the forced landing vehicle model using a refined part model at the current time step when the simple occupant injury evaluation data at any of the time steps exceeds a preset occupant part injury range; A first evaluation result generating module, configured to continue executing the forced landing numerical simulation from the current time step until the forced landing numerical simulation is completed, and construct a refined evaluation result of occupant damage; The model updating module is specifically used for: When the simple occupant injury assessment data of any of the time steps exceeds a preset occupant part injury range, locating the target part model to which the simple occupant injury assessment data belongs and splitting it; the occupant part injury range refers to a predetermined proportion value of the numerical range corresponding to each part of the simple occupant model; Acquire unit information of the target part model, and select a refined initial part model matching the target part model from a preset high biological simulation pseudo-human model; Using a linear interpolation method to transfer the unit information to the refined initial part model to obtain a refined part model; The refined part model and the simplified occupant model other than the target part model are connected at the current time step to automatically update the forced landing vehicle model.

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