A civil aircraft occupant head injury test device and its design method and application

Abstract

The invention discloses a civil aircraft occupant head injury test device and a design method and application thereof. The device comprises a base, a pendulum mechanism, an actuating mechanism and a power mechanism installed on the base; the pendulum mechanism comprises a rocker arm, a dummy head and a connecting neck, the dummy head is arranged at the upper end of the connecting neck, and the connecting neck is arranged between the dummy head and the rocker arm; the actuating mechanism comprises a support arm and a push rod, and the push rod is sleeved on the support arm; the power mechanism comprises an actuator cylinder and an actuator bracket, and the piston of the actuator cylinder is connected to the push rod through a transition connector; the lower ends of the rocker arm and the support arm are connected to the base through bearings; the dummy-rigid seat-slide system is simplified into a pendulum mechanism-actuating system, and a device for civil aircraft occupant head injury assessment is developed to conduct an assessment test of fatal head injury of the occupant, or to replace the slide test to assess the HIC value of horizontal collision between the occupant and the cabin interior, the first row partition plate and other interiors, with the characteristics of high accuracy and repeatable recycling.

Description

Technical Field

[0001] The invention relates to the technical field of civil aircraft occupant head injury test equipment, and in particular to a civil aircraft occupant head injury test device and a design method and application thereof. Background Art

[0002] In aviation safety, passenger safety is an important parameter indicator. In recent years, aviation safety accidents have occurred from time to time:

[0003] The head is the central nervous system and the command system of the human body. Once the head is seriously injured and causes coma, the occupant's survival rate or chance of secondary escape will be reduced. Therefore, aviation regulatory authorities in various countries have put forward clear requirements for head injuries of occupants under emergency landing conditions;

[0004] Airworthiness regulations CCAR25.562(c) states that "in situations where the head may contact the seat or other components, protection measures must be provided so that the head injury criterion (HIC) does not exceed 1000; and in Airworthiness regulations CCAR 25.785(b) requires: "Seats, berths, safety belts, shoulder harnesses, and nearby parts of the airplane in each position designated for occupation by persons during takeoff and landing must be designed so that persons using these facilities properly will not be seriously injured during an emergency landing due to the inertial forces specified in §§ 25.561 and 25.562." Therefore, in the airworthiness verification of seat installation, HIC-related verification items have the highest structural requirements and many structures need to be inspected, such as the first row of seats, row-by-row seats, equipment panels, etc.; in the airworthiness verification of seat installation, there are many head-related verification items, and different cabin layouts (such as straight sections, tail retracted sections, etc.), seat installation positions (such as first row seats, row-by-row seats, seats at emergency exits), seat configurations, and potential head collision surfaces (cabin interiors, etc.) must be inspected one by one.

[0005] Currently, most aviation seat manufacturers demonstrate HIC compliance through a series of full-size slide tests. For devices such as the head-up display (HUD) in the cockpit, fatal injury tests must be conducted using component testers such as bowling ball testers, head component testers, and free-moving head testers to demonstrate compliance with CCAR 25.785(b)(d). As for aircraft cabin interior structures such as lavatory wall panels and partition panels, most aviation seat manufacturers demonstrate HIC compliance through a series of full-size slide table tests. However, the seats used in these tests are usually scrapped after each test, resulting in huge costs. In addition to the numerous structures examined and the huge test costs, full-size slide table tests also have the disadvantages of low repeatability and long preparation cycles, which pose huge challenges to the industry. Therefore, a head injury test device that can combine experiments and simulations for civil aircraft occupant head injury assessment is designed and developed to test civil aircraft occupant head injuries. It can be used for fatal injury tests, or replace slide table tests to assess the HIC value of horizontal collisions between occupants and cabin partition panels, lavatory wall panels and other cabin interiors, saving a lot of test preparation cycles and providing support for the airworthiness verification of aviation seat installations.

[0006] It is necessary to provide guidance for the manufacture of head impact injury testing systems. Summary of the invention

[0007] In view of the above-mentioned problems, the present invention aims to provide a civil aircraft occupant head injury test device and its design method and application. The device simplifies the mixed III dummy-rigid seat-slide system into a pendulum mechanism-actuation system to form a device for evaluating civil aircraft occupant head injuries. The device has good applicability, can simulate occupant head injuries well, and has high test accuracy and can be reused. A device for evaluating civil aircraft occupant head injuries is developed. The device can perform occupant fatal head injury tests in accordance with ANM-03-115-31, or replace the slide test evaluation. It has high test accuracy and can be reused.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] A civil aircraft occupant head injury test device comprises a base, a pendulum mechanism, an actuating mechanism and a power mechanism installed on the base; the pendulum mechanism comprises a rocker arm, an FAA hybrid III dummy head and a connecting neck, the dummy head is arranged at the upper end of the connecting neck, and the connecting neck is arranged between the dummy head and the rocker arm; the actuating mechanism comprises a support arm and a push rod, the push rod is sleeved on the support arm, and the front end of the push rod contacts the rear side of the rocker arm; the power mechanism comprises an actuator cylinder and an actuator bracket, the actuator cylinder is installed on the actuator bracket, the actuator bracket is arranged on the base, and the piston of the actuator cylinder is connected to the push rod through a transition connector, and the rocker arm is pushed forward by the piston; the lower ends of the rocker arm and the support arm are connected to the base through a connecting assembly.

[0010] Preferably, the base comprises a chassis and a chassis bracket, and the chassis bracket is an I-beam structure and is symmetrically arranged on the lower side of the chassis.

[0011] Preferably, a connecting portion is provided at the lower end of the support arm, and the connecting assembly includes a bearing seat, a bearing seat bracket, a bearing group and a connecting shaft. The bearing seat bracket is arranged on the chassis, the bearing seat is bolted to the bearing seat bracket, and a bearing group is provided on the bearing seat. The bearing group is connected to the rocker arm or the connecting portion through the connecting shaft, and the rocker arm and the support arm are respectively installed between two symmetrical bearing seats.

[0012] Preferably, a support plate is provided on the actuator bracket, a cylinder bracket is provided on the support plate, a vertical bearing is provided on the cylinder bracket, and the actuator cylinder is mounted on the vertical bearing via a connecting shaft.

[0013] Preferably, the support plate is further provided with a movable notch at one end close to the rear end of the actuator cylinder body.

[0014] Preferably, the dummy head is an ellipsoidal structure with a connecting seat, which is connected to the connecting neck by bolts, and the connecting neck is connected to the rocker arm bolts.

[0015] Preferably, the support arm is provided with a plurality of connection holes, which are used in conjunction with the connection holes provided on the top rod.

[0016] A design method for a civil aircraft occupant head injury test device, the method comprising establishing and verifying a civil aircraft occupant head injury test model, specifically comprising the steps of:

[0017] S1. Establish a civil aircraft occupant head injury experimental model (pendulum model):

[0018] S101. Simplify the FAA Hybrid III numerical dummy into a pendulum model of "FAA Hybrid III dummy head and neck-rocker-ellipsoid";

[0019] S102. According to the established model, determine the geometry of the rocker arm and the lower ellipsoid and the mass distribution;

[0020] S2. Establish a simplified model of the pendulum mechanism-actuator:

[0021] S201. After determining the geometric and mass characteristics of the pendulum device, design the actuating mechanism of the pendulum, which provides a certain angular velocity for the rocker arm, so that the rocker arm rotates around the lower ellipsoid and collides with the cabin interiors such as the lavatory wall panel, the aircraft side wall panel, the partition panel and the front seat at a certain speed;

[0022] S202. Perform simulation analysis on the established simplified model of the pendulum mechanism-actuator to determine the specific structure of the actuator;

[0023] S3. Design a power mechanism; a power mechanism with an actuator cylinder as the actuating part.

[0024] The invention discloses an application of a civil aircraft occupant head injury test device, wherein the civil aircraft occupant head injury test device can perform an evaluation test of fatal head injury of occupants according to ANM-03-115-31, or replace a sliding table test to evaluate the HIC value of horizontal collision between occupants and cabin interiors or head row partitions.

[0025] The beneficial effects of the present invention are as follows: the present invention discloses a civil aircraft occupant head injury test device and a design method and application thereof. Compared with the prior art, the present invention has the following improvements:

[0026] (1) The present invention designs a civil aircraft occupant head injury test device and its design method and application. The device includes a base, a pendulum mechanism, an actuator mechanism and a power mechanism installed on the base. When in use, the actuator mechanism is pushed forward by the power mechanism, and the actuator mechanism pushes the pendulum mechanism forward to move, thereby simulating the injury to the occupant's head caused by the collision with the partition in an accident. It has been verified that: under the same head collision speed and head collision angle, the simplified model of the "pendulum mechanism-actuator device" can produce the same head injury criterion HIC as the full-scale slide test model;

[0027] (2) During the design process of the present invention, the components and kinematic pairs of the occupant head injury simulation device are designed and the kinematic mechanism is analyzed. The device's degree of freedom can meet the intended use. There is a linear relationship between the maximum movement speed of the head and the maximum output speed of the actuator. The key parameters such as the maximum output speed and thrust of the actuator are determined by inverting the maximum movement speed of the head. The key components of the head injury simulation device are strength-checked. The selected materials can meet the intended use. The deformation of the rocker arm has no effect on the movement trajectory of the head. The collision speed of the head of the flexible rocker arm and the rigid rocker arm are basically consistent. It is proved that the device can accurately evaluate and reflect the damage caused by accidental injury to the head of the civil aircraft occupant colliding with the aircraft interior in actual test. It has good applicability, can simulate the occupant's head injury well, and has the advantages of high test and evaluation accuracy and repeatable recycling. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The figure is a schematic structural diagram of the civil aircraft occupant head injury test device of the present invention.

[0029] Figure 2 It is a front view of the civil aircraft occupant head injury test device of the present invention.

[0030] Figure 3 It is a schematic structural diagram of the actuator cylinder of the present invention.

[0031] Figure 4 This is a design flow chart of the occupant head injury test device of civil aircraft embodiment 1 of the present invention.

[0032] Figure 5 This is a model diagram of the FAA hybrid III dummy head and neck-rocker-ellipsoid in Example 1 of the present invention.

[0033] Figure 6 This is a diagram of the division of human body segments according to Example 1 of the present invention.

[0034] Figure 7 This is a geometric feature diagram of the model of Example 1 of the present invention.

[0035] Figure 8 This is a comparison diagram of the center of gravity acceleration of the head of two models in Example 1 of the present invention.

[0036] Fig. 9 This is a comparison diagram of the center of gravity acceleration of the head of different rocker arm masses in Example 1 of the present invention.

[0037] Fig.10 This is a schematic diagram of the HCT model of Example 1 of the present invention.

[0038] Fig.11 This is a material model diagram of the front partition of Example 1 of the present invention.

[0039] Fig.12 This is a model diagram of the front row seats of Example 1 of the present invention.

[0040] Fig.13 This is a flow chart of the HCT model simulation method according to Example 1 of the present invention.

[0041] Fig.14 This is a comparison diagram of the head center of gravity acceleration-time curve of Example 1 of the present invention.

[0042] Fig.15 This is a schematic diagram of the head injury equivalent method according to Example 1 of the present invention.

[0043] Fig.16 This is a simplified model diagram of the pendulum mechanism-actuating device according to Example 1 of the present invention.

[0044] Fig.17 This is a schematic diagram of the motion mechanism of Example 1 of the present invention.

[0045] Fig.18 This is a virtual prototype of the head impact test system of Example 2 of the present invention.

[0046] Fig.19 This is a piston rod speed-time curve diagram of Example 2 of the present invention.

[0047] Fig. 20 This is a rocker arm head movement speed-time curve diagram of Example 2 of the present invention.

[0048] Fig.21 This is a diagram of the head movement speed under different rocker arm masses in Example 2 of the present invention.

[0049] Fig. 22 This is a diagram of the head movement speed under different rocker arm masses in Example 2 of the present invention.

[0050] Fig.23 This is the stress cloud diagram of the flexible rocker arm in Example 2 of the present invention.

[0051] Fig.24 This is a comparison diagram of the head movement trajectory of Example 2 of the present invention.

[0052] Fig.25 This is a comparison chart of head movement speeds in Example 2 of the present invention.

[0053] Fig.26 This is a linear fitting relationship diagram between the maximum head movement speed and the maximum output speed of the actuator in Example 2 of the present invention.

[0054] Fig. 27 This is a diagram of the hydraulic servo system of embodiment 2 of the present invention.

[0055] Fig.28 This is a piston movement speed-time curve diagram of Example 2 of the present invention.

[0056] Fig.29 This is a diagram of the working status of the device at different times in Example 2 of the present invention.

[0057] Fig.30 This is a diagram of the head movement speed and piston movement speed of Example 2 of the present invention.

[0058] Among them: 1. rocker arm, 2. support arm, 21. connecting hole, 3. push rod, 4. connecting part, 5. bearing seat, 6. bearing seat bracket, 7. chassis, 8. chassis bracket, 9. connecting shaft, 10. actuator bracket, 101. support plate, 102. vertical bearing, 103. cylinder bracket, 11. piston, 12. actuator cylinder, 13. bearing group, 14. dummy head, 15. adapter connector, 16. connecting neck. DETAILED DESCRIPTION

[0059] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0060] See also Figure 1-30 As shown, a civil aircraft occupant head injury test device and its design method and application, the civil aircraft occupant head injury test device includes a base, and a pendulum mechanism, an actuating mechanism and a power mechanism installed on the base; the pendulum mechanism includes a rocker arm 1, a pendulum FAA hybrid III dummy head 14 and a connecting neck 16, the dummy head 14 is arranged at the upper end of the connecting neck 16, simulating the occupant's head, the connecting neck 16 is arranged between the dummy head 14 and the rocker arm 1, and is connected to the dummy head 14 and the rocker arm 1 respectively by bolts to simulate the occupant's neck; the actuating mechanism includes a support arm 2 and a push rod 3, the push rod 3 is sleeved on the support arm 2, and the push rod end of the push rod 3 is connected to the rocker arm 1 The rear panel of the support arm 1 is in contact with the support arm 3. When in use, the rocker arm 1 is pushed forward by the push rod 3. The power mechanism includes an actuator cylinder 12 and an actuator bracket 10. The actuator cylinder 12 is installed on the actuator bracket 10. The actuator bracket 10 is arranged on the base. The piston 11 of the actuator cylinder 12 is connected to the push rod 3 through the adapter connector 15. When in use, the push rod 3 is pushed forward by the piston 11, and the push rod 3 further pushes the rocker arm 1 forward to simulate the condition that the body of the aircraft occupant leans forward and the head is forward under the condition of the aircraft crash. The lower ends of the rocker arm 1 and the support arm 2 are connected to the base through a connecting assembly, and the pendulum mechanism and the actuator mechanism are arranged on the base.

[0061] Preferably, the base includes a chassis 7 and a chassis bracket 8. To ensure the supporting force, the chassis bracket 8 is designed as an I-beam structure, symmetrically arranged on the lower side of the chassis 7, and bolted to the chassis 7.

[0062] Preferably, a connecting part 4 is provided at the lower end of the support arm 2. The connecting component includes a bearing seat 5, a bearing seat bracket 6, a bearing group 13 and a connecting shaft 9. The bearing seat bracket 6 is mounted on the chassis 7. The bearing seat 5 is bolted to the bearing seat bracket 6, and a bearing group 13 is provided on the bearing seat 5. The bearing group 13 is connected to the rocker arm 1 or the connecting part 4 through the connecting shaft 9, and the rocker arm 1 and the support arm 2 are respectively mounted (rotated) between two symmetric bearing seats 5.

[0063] Preferably, a support plate 101 is provided on the actuator bracket 10. A cylinder block bracket 103 is provided on the support plate 101. A vertical bearing 102 is provided on the cylinder block bracket 103. The actuator cylinder block 12 is mounted on the vertical bearing 102 to realize the movable mounting of the actuator cylinder block 12. An activity notch is further provided at one end of the support plate 101 close to the tail of the actuator cylinder block 12 to facilitate the movement of the actuator cylinder block 12.

[0064] Preferably, the dummy head 14 is an ellipsoidal structure with a connecting seat, which is bolted to the connecting neck 16, and the connecting neck 16 is bolted to the rocker arm 1.

[0065] Preferably, a plurality of connecting holes 21 are provided on the support arm 2, and the connecting holes 21 are used in cooperation with the connecting holes provided on the ejector rod 3 to facilitate adjusting the connecting height of the ejector rod 3 according to different experimental simulation requirements.

[0066] The application of the above civil aircraft occupant head injury test device includes:

[0067] S1. When using the above civil aircraft occupant head injury test device for experiments, the piston starts to accelerate from rest in the actuator cylinder block, decelerates after reaching the maximum speed until the speed is 0. The driving function of the actuator cylinder block is expressed by the IF function, and its format is:

[0068]

[0069] The driving function expression of the piston 11 is as follows:

[0070]

[0071] In the formula: time, that is, t represents time, with the unit of s. When t - 0.03 < 0, the function output , that is, in the first 0.03 s, the actuator cylinder block has a uniform acceleration motion with an acceleration of 200 m / s 2 ; when t = 0.03, the function return value is x 3 = 6, and the maximum speed is 6 m / s at this time; when t - 0.03 > 0, the function return value is , that is, when 0.03 < t < 0.045, the actuator cylinder block has an acceleration of 400 m / s2 The motion is then stopped after a uniform deceleration.

[0072] S2. When the piston pushes the push rod against the rocker arm, the rocker arm moves forward. The HIC value of the head injury of the civil aircraft occupants under the condition of aircraft crash is evaluated based on the driving function of the piston and the motion trajectory of the pendulum.

[0073] Embodiment 1:

[0074] A design method for a civil aircraft occupant head injury test device as shown above, the method includes establishing and verifying a civil aircraft occupant head injury test model, specifically comprising the steps of:

[0075] S1. Establish a civil aircraft occupant head injury experimental model (pendulum model):

[0076] S101. Simplify the FAA Mixed III numerical dummy into a pendulum model of "FAA Mixed III dummy head and neck-rocker-ellipsoid", such as Figure 5 As shown; the main purpose of this analysis is to determine the geometry of the rocker arm, the lower ellipsoid and the mass distribution;

[0077] S102. According to the established model, determine the geometric shape and mass distribution of the rocker arm and the lower ellipsoid, including:

[0078] (1) In the pendulum model, the rocker arm represents the spine and upper torso of the FAA Mixed III dummy, and the lower ellipsoid represents the lower torso, legs and feet of the FAA Mixed III dummy; the human body segments are divided as follows: Figure 6 As shown; the geometry, mass distribution and moment of inertia of the pendulum mechanism need to be representative of the FAA Mixed III dummy. The dimensions, mass distribution and moment of inertia of the main body parts of the FAA Mixed III dummy are summarized in Table 1-3:

[0079] Table 1: FAA Hybrid III Dummy Mass Distribution

[0080] ;

[0081]

[0082] Table 2: FAA Hybrid III Dummy Dimensions

[0083]

[0084] Table 3: FAA Mixed III Dummy Moment of Inertia

[0085]

[0086] First, determine the height of the rocker arm and the size of the lower ellipsoid according to the dimensions of the FAA hybrid III dummy; Figure 7 As shown, at the initial moment, the height of the lower torso of the FAA hybrid III dummy from the seat reference point is 0.16m, and the height of the lower end of the neck from the seat reference point is about 0.6m, so the height of the lower ellipsoid is selected to be 0.16m, and the height of the rocker arm is 0.44m; the rocker arm and the lower ellipsoid are connected by a rotary hinge to simulate the rotation of the waist of the occupant under horizontal impact, the rocker arm and the neck are connected by a fixed hinge, and the lower ellipsoid and the seat basin are connected by a fixed hinge;

[0087] The geometric characteristics of the model significantly affect the occupant's head movement trajectory. The comparison of the head center of gravity movement trajectory of the two models is shown in Figure 2. Figure 8 As shown in the figure, it can be seen that the head trajectories of the two models deviate when the horizontal displacement (X-direction displacement) is 0.78m and the vertical displacement (Z-direction displacement) is 0.24m. This point is called the deviation point. The head center of gravity motion trajectories of the two models are basically the same before this point, and there is a big difference after this point. This is mainly because the FAA hybrid III dummy has two degrees of freedom of movement under horizontal impact. In addition to the rotation of the waist, there is also a relative sliding between the dummy's hips and the seat basin; while the pendulum model has only one degree of freedom of movement, that is, the rocker arm rotates through the rotary joint; the movement of different degrees of freedom makes the head motion trajectories of the two models differ greatly after the split point.

[0088] (2) After determining the geometric characteristics of the pendulum model, its mass distribution must also be determined. The mass distribution of the model significantly affects the composite acceleration of the occupant's head. When simplifying the FAA hybrid III dummy, the rocker arm represents the spine, upper torso, arms, and hands of the FAA hybrid III dummy, and the lower ellipsoid represents the lower torso, legs, and feet of the FAA hybrid III dummy. Therefore, the mass of the rocker arm is the sum of the mass of the upper torso, upper arm, forearm, and hand of the FAA hybrid III dummy, which is 25.75 kg. The mass of the lower ellipsoid is the sum of the mass of the lower torso, thigh, calf, and foot, which is 43.49 kg. In addition to the mass, the moment of inertia of the rocker arm during rotation will also affect the head response. The moment of inertia of each part of the pendulum model is summarized in Table 4. Since the lower ellipsoid representing the lower torso of the dummy is fixed on the seat basin, the moment of inertia of this part is not considered.

[0089] Table 4: Pendulum model moment of inertia

[0090]

[0091] Comparison of the head center of gravity acceleration of the occupant in the pendulum model and the full-scale slide model Figure 8 shown; from Figure 8 It can be seen that the acceleration of the center of gravity of the head of the two models is quite different, mainly because in the full-scale slide model, the inertia of the arms, legs, and feet will affect the acceleration of the center of gravity of the occupant's head;

[0092] The following parameter study is conducted on the mass of the rocker arm, so that the acceleration of the center of gravity of the head of the two models is basically the same. Since the lower ellipsoid and the seat basin are connected by a consolidation hinge in the pendulum model, there is no relative sliding between the lower ellipsoid and the seat basin under horizontal impact, so the mass of the lower ellipsoid has no effect on the acceleration of the center of gravity of the occupant's head. Only the parameter study is conducted on the mass of the rocker arm: simulation models with rocker arm masses of 5kg, 10kg, 15kg, 20kg and 25kg are designed, and the comparison of the acceleration of the center of gravity of the occupant's head is obtained. Fig. 9 As shown, from Fig. 9 It can be seen that for rocker arms of different masses, the peak time of the head center of gravity acceleration is basically the same, and the shape of the head acceleration-time curve is also basically the same; with the increase of the rocker arm mass, the peak value of the head center of gravity acceleration increases; the peak value errors of the head acceleration of the pendulum model and the full-scale slide model under different rocker arm masses are summarized in Table 5. It can be seen that when the rocker arm mass is 15kg, the peak value error of the head acceleration of the two models is the smallest, which is 3.23%, so the mass of the selected rocker arm is 15kg; the sum of the mass of the upper torso, upper arm, forearm and hand of the FAA hybrid III dummy is 25.75kg, and the rocker arm mass is 15kg. The reason for the mass difference between the two is that in the full-scale slide model, the inertia of the arms, legs and feet will affect the acceleration of the occupant's head center of gravity;

[0093] Table 5: Peak value error of head center of gravity acceleration under different rocker arm masses

[0094]

[0095] S2. Establish a simplified model of the pendulum mechanism-actuator;

[0096] S201. After determining the geometric and mass characteristics of the pendulum device, design the pendulum's actuating mechanism, which provides a certain angular velocity for the rocker arm, so that the rocker arm rotates around the lower ellipsoid and collides with the lavatory wall panel, aircraft side wall panel, compartment panel and other cabin interiors at a certain speed, specifically including:

[0097] (1) In the process of simplifying the model, the geometric shapes of the rocker arm and the lower ellipsoid and the applicable scope of the model are determined by comparing the motion trajectory of the head of the full-size slide model and the pendulum model. The mass of the rocker arm is determined by comparing the acceleration of the center of gravity of the head. After determining the geometric and mass characteristics of the pendulum device, it is necessary to equate the acceleration applied to the slide to the output of the actuator. The actuator provides a certain angular velocity for the rocker arm, so that the rocker arm rotates around the lower ellipsoid and collides with the cabin internal facilities such as the partition plate and the front seat at a certain speed. The model with the actuator added is called the pendulum mechanism-actuator model. This model is as follows: Fig.10 As shown;

[0098] (2) In the aviation field, the head injury criterion (HIC) is considered only when the occupant's head hits the cabin interior and the fuselage structure. In order to verify that the simplified model of the "pendulum mechanism-actuator" can produce a head injury criterion HIC that is basically consistent with the full-scale slide model, a front partition is added to the full-scale slide model. Based on the verified full-scale slide model and combined with the FAA's static material test on the Boeing 727 front partition, a partition material model including loading and unloading load-displacement curves and hysteresis slope is established; the material model of the front partition is as follows Fig.11 As shown; the established front row seat model is as follows Fig.12 As shown; the front bulkhead is 31 inches from the seat reference point;

[0099] S202. Perform HCT model simulation analysis on the established simplified model of the pendulum mechanism-actuator to determine the specific structure of the actuator, including:

[0100] The speed of the occupant's head hitting the front partition is obtained through the simulation results of the full-scale sliding table model , Collision Angle , input this parameter into the pendulum mechanism-actuator model; obtain the desired head impact angle by adjusting the distance between the simplified model and the front partition , adjust the output speed of the actuator to obtain the desired head impact speed v ; Pendulum mechanism-actuator model simulation method such as Fig.13 As shown;

[0101] The head acceleration-time curves of the full-scale slide model and the pendulum mechanism-actuator model are shown in Figure 2. Fig.14 As shown, the curve errors are summarized in Table 6. The head center of gravity acceleration-time curves of the two models have a high degree of consistency;

[0102] Table 6: Error values ​​of synthetic acceleration-time curves of the head of two models

[0103] ;

[0104] (3) The summary of the head dynamic response is shown in Table 7. Under the same head impact angle and head impact speed, compared with the full-scale slide test model of "aviation dummy-seat and restraint system-slide", the head injury criterion HIC error produced by the simplified model of "pendulum mechanism-actuator" is 3.5%. The simplified model of "pendulum mechanism-actuator" can also produce basically consistent head injury criterion HIC;

[0105] Table 7: Comparison of head dynamic response

[0106] ;

[0107]

[0108] (4) Under the same head collision speed and collision angle, the "pendulum mechanism-actuator" can produce head injuries that are basically the same as those of the full-size slide model; the movement trajectory of the occupant's head center of gravity in the full-size slide model is shown in the figure below. The head center of gravity at different positions has different head movement speeds; in the full-size slide test, the head position at each moment and the head movement angle and speed at the corresponding position can be collected by high-speed camera; Fig.15 As shown, for example, if the front partition is placed at an X-coordinate of -0.6 m, the head angle and speed of the head at this position can be known through high-speed camera data, that is, the head collision speed and head collision angle; the same head collision angle can be achieved by adjusting the distance between the simplified model of the "pendulum mechanism-actuator" and the front partition; the same head collision speed can be achieved by adjusting the actuator output of the simplified model of the "pendulum mechanism-actuator"; under the same head collision angle and collision speed, basically consistent head injuries can be achieved.

[0109] S3. Design a power mechanism; a power mechanism with an actuator cylinder as the actuating mechanism, specifically including:

[0110] (1) Under the same head impact speed and head impact angle, the simplified model of the “pendulum mechanism-actuator” can produce the head injury criterion HIC that is basically consistent with the full-scale slide test model. The kinematic pairs involved in the simplified model of the “pendulum mechanism-actuator” are as follows: Fig.16 As shown; the rocker arm is connected to the lower ellipsoid through a revolute pair, the support arm is connected to the base through a revolute pair, and the support arm extension section is connected to the support arm through a fixed pair, and the two components can be regarded as a whole; the support arm pushes the rocker arm to rotate in the XZ plane through the contour of the extension section, and the contact between the two can be regarded as a push rod pair;

[0111] (2) In the simplified model of the "pendulum mechanism-actuator", the driving function is added to the revolute pair of the support arm and the base, and the rocker arm is driven to rotate through the contour of the extension section; in the head injury simulation device, in addition to the rocker arm, the lower ellipsoid, the support arm extension section, the support arm and its base, it should also include a power device such as an actuator; the actuator piston is connected to the support arm extension section, and when the piston is extended, it will drive the support arm to rotate, thereby driving the rocker arm to rotate. The schematic diagram of the designed head injury simulation device motion mechanism is shown in the figure below. Fig.17As shown; since all components move in the plane XZ, it can be simplified into a planar motion mechanism. In this device, the stationary components such as the lower ellipsoid of the rocker arm, the base of the support arm, and the actuator bracket are used as the frame. The piston in the actuator cylinder of the power device is used as the driving part, and other devices such as the rocker arm, the support arm, and the actuator cylinder block are used as the driven parts, thus designing the structural schematic diagram of the civil aircraft occupant head injury test device as shown in Figure 1 shown.

[0112] Embodiment 2:

[0113] Perform kinematic analysis on the above-mentioned civil aircraft occupant head injury test device, specifically including the steps:

[0114] S1. First, establish a 3D model of the civil aircraft occupant head injury test device as shown in Figure 1 shown. According to the geometric characteristics, mass characteristics and other parameters of the head and neck of the FAA Hybrid III physical dummy, establish entities representing the dummy's head and neck in Adams, add material properties to each component, and set the contact between the extended section of the support arm and the rocker arm. The virtual prototype of the head injury simulation device established is as shown in Fig.18 shown;

[0115] S2. Under real conditions, the piston 11 starts to accelerate from rest in the actuator cylinder 12, starts to decelerate after reaching the maximum speed until the speed is 0;

[0116] The driving function is expressed using the IF function, and its format is: ;

[0117]

[0118] The expression of the driving function of the piston 11 is as follows:

[0119] ;

[0120] In the formula: time, that is, t represents time, with the unit of s. When t - 0.03 < 0, the function outputs , that is, in the first 0.03 s, the actuator cylinder has a uniform acceleration motion with an acceleration of 200 m / s 2 . When t = 0.03, the function return value is x 3 = 6, and the maximum speed is 6 m / s at this time. When t - 0.03 > 0, the function return value is , that is, when 0.03 < t < 0.045, the actuator cylinder has a uniform deceleration motion of 400 m / s 2 , and then stops moving;

[0121] (1) For the convenience of research, this embodiment uses uniformly accelerated linear motion to represent the acceleration section of the piston 11, and uses uniformly decelerated linear motion to represent the deceleration section of the piston 11. The motion of the piston 11 under this driving function is summarized in Table 8 below. The velocity-time curve of the center of mass motion of the piston rod is shown in Fig.19 As shown;

[0122] Table 8: Piston movement

[0123] ;

[0124] It can be seen that during the simulation: after the piston 11 is extended, the support arm 2 is pushed to rotate through the rotation pair of the piston 11 and the extension section of the support arm 2, and the support arm 2 pushes the rocker arm 1 to rotate in the plane through the push rod. The structural design of the head injury simulation device can realize the function of the ideal motion mechanism;

[0125] (2) When the piston 11 moves according to the motion conditions shown in Table 8, the upper end head movement speed-time curve of the rocker arm 1 is as follows: Fig. 20 As shown, the head movement speed can be divided into three stages; the first stage is from the initial moment to 0.03s, during which the piston rod performs uniform acceleration motion, and the rocker arm starts to move under the push of the support arm extension section. As the piston rod speed increases, the head movement speed also increases, and this stage is called the acceleration stage; the second stage is from 0.03s to 0.035s, during which the piston rod reaches the maximum speed and starts to decelerate, and the support arm extension section is disconnected from the rocker arm, and this stage is called the transition stage; the third stage is from 0.035s to the end, during which the rocker arm has been disconnected from the support arm extension section and continues to move under the action of inertia, and the change in gravitational potential energy has little effect on the head speed, resulting in the head movement speed remaining basically unchanged, and this stage is called the uniform speed stage;

[0126] It can be seen from the head movement speed-time curve of the head injury simulation device that after the actuator reaches the maximum speed and starts to decelerate, the support arm extension section is disengaged from the rocker arm. Due to the inertia of the head and the rocker arm, the mass and material of the rocker arm will also affect the dynamic response of the head. In the pendulum model, the mass of the rocker arm is selected to be 15 kg according to the synthetic acceleration of the head of the pendulum model and the full-size slide model. However, it is found in the simulation that the influence of gravitational potential energy on the head speed is negligible. As the mass of the rocker arm increases, the output thrust required by the actuator is also greater, and the requirements for the actuator cylinder 12 are also more stringent.

[0127] (3) The rocker arm masses are selected as 3kg, 7kg, and 15kg respectively. Under the same driving function, the motion results are as follows: Fig.21 and Fig. 22As shown in the figure, the movement speed and acceleration of the head are basically the same, so the influence of the rocker arm mass on the movement speed and acceleration of the head can be ignored; with the increase of the rocker arm mass, the output thrust required by the actuator is also greater, and the requirements for the actuator are also more stringent; therefore, the mass of the rocker arm 1 can be reduced in the device, the rocker arm material is Al6061, and the final rocker arm mass is selected to be 5.58 kg; in the pendulum model, with the increase of the rocker arm mass, the peak value of the head acceleration increases; in the pendulum mechanism-actuator model, under the same drive, the rocker arm mass has basically no effect on the head movement acceleration. The reason for this phenomenon is that in the pendulum model, the acceleration is loaded onto the slide, and the rocker arm rotates around the rotation axis under the action of inertia force, so the mass of the rocker arm will significantly affect the rotation acceleration, and then affect the head acceleration; but in the pendulum mechanism-actuator model, the acceleration is directly loaded onto the rocker arm, and the rocker arm rotation acceleration is only related to the output acceleration of the actuator, and has nothing to do with the rocker arm mass, so in the pendulum mechanism-actuator model, the rocker arm mass will not affect the head acceleration.

[0128] S3. Kinematic analysis considering structural flexibility

[0129] In the analysis models of the above steps S1 and S2, each component is a rigid body and will not deform under the action of external force, but such a rigid body does not exist in reality; in this model, the support arm extension section contacts the rocker arm, thereby pushing the rocker arm to move. In this process, the rocker arm will deform under the force. The above model does not consider the deformation of the rocker arm 1. Next, the rocker arm will be made flexible to study the deformation of the rocker arm and the influence of the flexible body on the dynamic response of the head;

[0130] (1) Make the rigid body model established in step S1 flexible and establish a flexible rocker arm. After making the rocker arm rigid body flexible, it is necessary to establish the contact between the rocker arm and the extension section of the support arm. The materials of the components of this device are mainly aluminum alloy and steel. The failure of the material is marked by plastic deformation. Therefore, Von Mises stress can be used for strength verification. During the working process, the maximum Von Mises stress of the rocker arm 1 is 77.8MPa. Fig.23 As shown, the allowable stress is less than that of Al 6061, and the material selection meets the use requirements;

[0131] The deformation of the rocker arm 1 will also affect the dynamic response of the head, such as Fig.24 and Fig.25 As shown in the figure, it can be seen from the simulation results that the deformation of the rocker arm has basically no effect on the head movement trajectory; the deformation of the rocker arm has a more obvious effect on the head movement speed, especially in the acceleration section and the transition section. In these two stages, the flexible head movement speed is significantly greater than the rigid body, but in the uniform speed section, the head movement speeds of the two are basically consistent, that is, the collision speed of the flexible head is basically consistent with the collision speed of the rigid head.

[0132] S4. Power mechanism parameter requirement analysis and verification

[0133] The maximum output speed of the actuator cylinder determines the head movement speed. Next, the driving function of the actuator cylinder is changed to study the relationship between the maximum output speed of the actuator cylinder and the head movement speed.

[0134] (1) The acceleration stroke of the actuator is set to 0.1 m. As shown in Table 9, as the maximum output speed of the actuator increases, the maximum movement speed of the head also increases. There is a linear relationship between the maximum movement speed of the head and the maximum output speed of the actuator, such as Fig.26 As shown, according to the linear relationship, the maximum output speed of the actuator can be inverted and deduced when the head movement speed is known, so as to set the actuator parameters accordingly;

[0135] Table 9: Maximum output speed of the actuator and the corresponding maximum movement speed of the head

[0136]

[0137] (2) According to the head-row seat collision test conducted by the FAA, the head collision speed is generally around 12-15m / s. Based on the obtained linear fitting relationship between the maximum output speed of the actuator and the maximum movement speed of the head, and considering the influence of factors such as friction and air resistance in actual conditions, the maximum output speed of the actuator is selected to be 8m / s, and the maximum thrust is about 30kN. In addition, there are also requirements for the maximum stroke of the actuator. If the maximum stroke is too large, it may cause interference between the various components of the head injury simulation device. Based on the principle that the various components of the head injury simulation device do not interfere with each other, the maximum stroke of the actuator is determined to be 350mm. The power device parameter requirements are summarized in Table 10:

[0138] Table 10: Power plant parameter requirements

[0139]

[0140] After determining the parameters of the power device, the power mechanism is designed and manufactured, such as Fig. 27 As shown, it is mainly composed of hydraulic cylinder, accumulator, hydraulic source, electronic control system and test bench; the hydraulic servo system has large output power, fast loading speed, high repetition accuracy, convenient parameter setting, and is designed with energy absorption structure and matching protection device. The actuator is the actuator of the hydraulic servo system. The piston rod of the actuator is connected to the extension section of the support arm through the front spherical end to provide angular velocity for the rotation of the support arm and the rocker arm; the cylinder, piston rod, pull rod and other parts are quenched and tempered, and the front end of the piston rod is equipped with a spring to increase the buffer and reduce the impact; both ends of the actuator are equipped with external spherical seated vertical bearings, which provide rotational freedom for the actuator and fix the actuator to the actuator bracket;

[0141] In order to verify whether the designed hydraulic servo system meets the functional requirements, the system was tested several times to confirm that the hydraulic servo system can work normally and meet the use requirements; the speed sensor was used to collect the piston movement speed, and the test data was imported into the virtual prototype of the head injury simulation device for kinematic simulation to confirm whether the head collision speed can meet the expected requirements; a total of 8 tests were carried out, and different working pressures were set for each test. The piston movement speed-time curve obtained by the test is shown in the figure. Fig.28 As shown, the maximum movement speed of the piston can reach 15m / s, which meets the parameter requirements;

[0142] (3) Taking the above piston motion speed-time curve as an example, the data is imported into the model and used as the driving function of the virtual prototype of the head injury simulation device for kinematic simulation. After setting the driving function, the kinematic simulation is performed to obtain the working condition of the device. Fig.29 As shown, it can be seen that there is no interference between the components under this drive; the piston movement speed-time curve and the head movement speed-time curve are summarized as follows Fig.30 shown; from Fig.30 It can be seen that after the rocker arm and the support arm extension are disconnected, the head movement speed is about 18m / s, which is greater than the empirical value of the head collision speed (12-15m / s), that is, the design of the hydraulic servo system meets the head collision speed parameter requirements. The main functional parameters of the hydraulic servo system are summarized in Table 11:

[0143] Table 11: Hydraulic servo system function parameter table

[0144]

[0145] Through the above embodiment, based on the verified aviation dummy / seat restraint system model, a simplified pendulum model is established and its effectiveness is verified; based on the simplified pendulum model, various components of the occupant head injury simulation device are designed and the motion mechanism analysis is performed, a virtual prototype is established in Adams for dynamic analysis, and the key parameters of the power device and the deformation of key components are identified. The following conclusions can be obtained:

[0146] (1) Under the same head impact speed and head impact angle, the simplified model of the “pendulum mechanism-actuator” can produce a head injury criterion HIC similar to that of the full-scale sliding table test model, with an error within 10%;

[0147] (2) Design the components and kinematic pairs of the occupant head injury simulation device and analyze the kinematic mechanism. The device's degrees of freedom can meet the intended purpose. There is a linear relationship between the maximum head movement speed and the maximum output speed of the actuator. The key parameters such as the maximum output speed and thrust of the actuator are determined by inverting the maximum head movement speed.

[0148] (3) The strength of the key components of the civil aircraft occupant head injury test device was checked. The selected materials can meet the expected use. The deformation of the rocker arm has no effect on the movement trajectory of the head. The collision speed of the head of the flexible rocker arm and the rigid rocker arm is basically the same. This proves that this test device can accurately evaluate the damage caused by the collision of the head of a civil aircraft occupant with the cabin interior in practice, and has the advantages of high accuracy and repeatability.

[0149] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for using a civil aircraft occupant head injury test device, the test device comprising a base, and a pendulum mechanism, an actuating mechanism and a power mechanism mounted on the base; the pendulum mechanism comprising a rocker arm (1), an FAA hybrid III dummy head (14) and a connecting neck (16), the dummy head (14) being arranged at the upper end of the connecting neck (16), and the connecting neck (16) being arranged between the dummy head (14) and the rocker arm (1); the actuating mechanism comprising a support arm (2) and a push rod (3), the push rod (3) being sleeved on the support arm (2), The front end of the push rod (3) contacts the rear side of the rocker arm (1); the power mechanism comprises an actuator cylinder (12) and an actuator bracket (10); the actuator cylinder (12) is mounted on the actuator bracket (10); the actuator bracket (10) is arranged on a base; the piston (11) of the actuator cylinder (12) is connected to the push rod (3) via a transition connector (15); the rocker arm (1) is pushed forward by the piston (11); the lower ends of the rocker arm (1) and the support arm (2) are connected to the base via a connecting assembly, characterized in that: The method of use specifically comprises the steps of: S1. Establishing a civil aircraft occupant head injury experimental model, wherein the civil aircraft occupant head injury experimental model is a pendulum model; S2. Establish a simplified model of the pendulum mechanism-actuator; S3. The actuator cylinder (12) is used as a power mechanism of the actuating portion; S4. Kinematic analysis using a civil aircraft occupant head injury test device; The specific operation of step S1 includes the following steps: S101. Simplify the FAA Hybrid III numerical dummy into a pendulum model of "FAA Hybrid III dummy head and neck-rocker-ellipsoid"; S102. According to the pendulum model, determine the rocker arm (1), the geometry of the lower ellipsoid and the mass distribution; The mass of the rocker arm (1) is the sum of the mass of the upper torso, upper arm, forearm and hand of the FAA hybrid III dummy, and the mass of the lower ellipsoid is the sum of the mass of the lower torso, thigh, calf and foot. During the rotation process, the moment of inertia of the rocker arm (1) will also affect the head response. The specific operation of step S2 includes the following steps: S201. Determine the geometric shape of the rocker arm (1) and the lower ellipsoid and the applicable scope of the model by comparing the head motion trajectory of the full-size slide model with the pendulum model, determine the mass of the rocker arm (1) by comparing the acceleration of the center of gravity of the head, and equate the acceleration applied to the slide to the output of the actuator; S202. Perform HCT simulation analysis on the established pendulum mechanism-actuator simplified model to determine the specific structure of the actuator; The specific operation of step S4 includes the following steps: S401. Establish a three-dimensional diagram of a civil aircraft occupant head injury test device, and establish entities representing the dummy head (14) and neck in Adams based on the geometric characteristics and mass characteristic parameters of the FAA hybrid III physical dummy head (14) and neck, add material properties to each component, and set the contact between the extension section of the support arm (2) and the rocker arm (1); S402. In a real situation, the piston (11) starts to accelerate from rest in the actuator cylinder (12), and after reaching the maximum speed, starts to decelerate until the speed reaches 0; S403. The rocker arm (1) is flexible, and the deformation of the rocker arm (1) and the influence of the flexible body on the dynamic response of the head are studied; S404. Change the driving function of the actuator cylinder (12) and study the relationship between the maximum output speed of the actuator cylinder (12) and the head movement speed.

2. A method for using a civil aircraft occupant head injury test device as claimed in claim 1, characterized in that: The base comprises a chassis (7) and a chassis bracket (8); the chassis bracket (8) is an I-beam structure and is symmetrically arranged on the lower side of the chassis (7); The support arm (2) is provided with a connecting portion (4) at the lower end thereof, the connecting assembly comprising a bearing seat (5), a bearing seat bracket (6), a bearing group (13) and a connecting shaft (9), the bearing seat bracket (6) being arranged on the chassis (7), the bearing seat (5) being bolted to the bearing seat bracket (6), and a bearing group (13) being arranged on the bearing seat (5), the bearing group (13) being connected to the rocker arm (1) or the connecting portion (4) via the connecting shaft (9), and the rocker arm (1) and the support arm (2) being movably mounted between two symmetrical bearing seats (5); The actuator bracket (10) is provided with a support plate (101), the support plate (101) is provided with a cylinder bracket (103), the cylinder bracket (103) is provided with a vertical bearing (102), and the actuator cylinder (12) is mounted on the vertical bearing (102) via a connecting shaft; The support plate (101) is also provided with a movable notch at one end close to the rear of the actuator cylinder body (12); The dummy head (14) is an ellipsoidal structure with a connecting seat, which is connected to the connecting neck (16) by bolts, and the connecting neck (16) is connected to the rocker arm (1) by bolts; The support arm (2) is provided with a plurality of connection holes (21), and the connection holes (21) are used in conjunction with connection holes provided on the top rod (3).

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