JP4141367B2 - Vehicle collision simulation program and device - Google Patents

Description

  The present invention relates to a technique for simulating the behavior of a dummy at the time of collision of a vehicle on which a dummy doll (hereinafter simply referred to as a dummy) that simulates an occupant is mounted.

  In the well-known vehicle crash test (sled test) using a dummy, a sensor such as a six-component force meter or an accelerometer is attached to the dummy, and the neck and chest of the dummy at the time of collision measured by the six-component force meter Calculate the longitudinal and lateral shear forces, vertical axial force, longitudinal and lateral moments, rotational moments, etc. of each part from the force applied to the waist and thighs, and calculate the dummy head from the measured values of the accelerometer. The acceleration in the X, Y, and Z directions on the chest and the chest is calculated, and the behavior of the dummy at the time of collision is evaluated from the calculation result. Hybrid III is known as such a dummy. However, the accuracy is not as high as expected, although a considerable burden is imposed on the adjustment of a large number of mounted sensors and the evaluation of their measured values.

As an improvement of the vehicle crash test using such a dummy, three-dimensional outline information of the dummy in the state of being seated on the seat of the stationary vehicle and a predetermined position of the dummy doll in the state of being seated on the seat of the stationary vehicle Each of the acceleration sensors based on the output signal from each acceleration sensor in a predetermined period ranging from a predetermined time before the collision of the vehicle to a predetermined time after the collision. The amount of displacement and the amount of rotation of the mounting position are determined, and the dummy three-dimensional outline information is sequentially changed based on the amount of displacement and the amount of rotation of the mounting position of each acceleration sensor for each predetermined period, and the changed dummy A vehicle collision simulation system with image analysis that displays a 3D image of a dummy doll based on the 3D outline information of the doll Is (e.g., see Patent Document 1.). According to this, a dummy three-dimensional image is displayed over time based on output signals from each acceleration sensor for each predetermined period from a predetermined time before the collision of the vehicle to a predetermined time after the collision. It is possible to know in detail the behavior of the dummy at the position where photography was not possible. However, in the crash test using a dummy, each of a large number of members constituting the dummy has nonlinear material characteristics, so that there is a drawback that it is difficult to apply the behavior of the dummy as it is to a human body damage simulation in an actual crash. In addition, the vehicle collision simulation system to which image analysis is added has the disadvantage that the system scale becomes large and the cost is too high.

In recent years, traffic accidents have been made using collision analysis software (for example, MADYMO manufactured by the Netherlands Applied Science Research Organization) that represents each part of the human body in a mass system and analyzes the human body by joining the mass points with elastic properties and various joint structures. Technology is known to analyze injury and further develop it to construct a finite element model of the whole human body and a finite element model of vehicle components, and to reproduce human injury from simulation results at the time of vehicle collision (For example, refer to Patent Document 2 or Non-Patent Document 1). However, in the case of simulation using the finite element method, a detailed dimensional layout of the vehicle is required, but it is difficult to accurately provide such data in an actual prototype vehicle or the like. Even if such data is given, it takes time and cost to prepare for the calculation and the calculation itself, and it is virtually impossible to use it frequently in the vehicle body design stage.

Japanese Patent Laid-Open No. 9-297087 (paragraph numbers 0008 to 0009, FIG. 1)

Japanese Patent Laid-Open No. 2002-149719 (paragraph numbers 0018 to 0019, FIG. 1)

Yoshikatsu Kisanuki et al. “R & D Review of Toyota Vol.32 No.2”, June 2002, p.34-40

  In view of the above situation, an object of the present invention is to use a simplified dummy and a vehicle model to simulate a vehicle collision with high accuracy even though the number of input parameters is small and the calculation time is short. Is to provide.

In order to solve the above-described problem, a vehicle collision simulation program according to the present invention relates to a dummy placed on a vehicle seat, a mechanical model composed of two mass points of a chest and a waist, and at least a seat belt for restraining the dummy on the seat. restraint comprising about, given the waist belt is given a spring characteristic and a dynamic model constituted by the shoulder belt and knee bolster with force limiter alone motion before Symbol chest only the chest motion equation lumbar only a single movement vehicle by inputting to the function of setting a lumbar motion equation has a function of substituting the spring characteristics of the dynamic model which is identified through a dummy thread test to each motion equation, a forced deceleration waveform to the vehicle and a function of calculating a dummy behavior at the time of collision, the rotational movement the chest centering the waist As features and capabilities to correct the final deceleration of the breast considered, a function of outputting at least one of the deceleration characteristic view and the movement amount diagram of the dummy components of the calculation result, that causes a computer to execute the Yes.

In this vehicle collision simulation program , in addition to the car body and the dummy, a restraint body that restrains the dummy such as a seat belt to the car body seat is modeled as a relatively simple dynamic model using spring characteristics, and the motion equation of this model is calculated as a dummy. -Solve by giving the spring characteristics of the dynamic model identified through the thread test and the collision deceleration characteristics of the vehicle model, and determine the behavior of the dummy at the time of the vehicle collision. Since the model used here is a simple dynamic model, even a small computer system can be quickly compared to a technology that divides the human body into finite elements and simulates vehicle collisions by large-scale calculations. An operation result is obtained. In addition, because the seat belt as a restraint that restrains the dummy to the vehicle body seat is accurately modeled, the vehicle is placed on the wall or facing the vehicle even though a simple spring mass model is used to shorten the computation time. In the case of a frontal collision with a car, it can be answered with satisfactory accuracy to the question of whether the chest is in contact with a vehicle member such as a handle. Therefore, by using this simulation technique, the vehicle body designer can obtain useful design information by repeating the simulation with various values even when the dimensions of the vehicle body are not accurately determined. Furthermore, the mechanical model for the dummy is composed of two mass points, the chest and the waist, and the chest motion equation for the sole motion of the chest and the chest motion equation for the sole motion of the chest are created. The chest is centered on the waist. It is considered a rotational movement and the final chest deceleration is corrected. Thereby, the calculation is simplified and the calculation time can be shortened.

Specific examples of the dynamic model with a simple spring mass model better results, in a preferred embodiment of the present invention, with respect to the dynamic model of the previous SL restraint against shoulder belt force limiter operation before After the force limiter is activated, different load characteristics are set, and the spring characteristics are set for the knee bolster separately for the soft cushion area and the non-soft cushion area. Even with a simple dynamic model in which the dummy is composed of two mass points of the chest and waist, the behavior of the chest and waist that is important in collision injury evaluation is affected by the waist belt and shoulder belt that have a large effect on the behavior. Since the knee bolster is accurately modeled and the mechanical linkage between the chest and the waist is sufficiently taken into consideration, simulation with good accuracy is possible. In addition, the spring characteristic regarding a knee bolster is good to identify through a heel compression test.

The present invention, medium recording a vehicle collision simulation pump program described above also it is an object of the right.

In the present invention, a vehicle collision simulation apparatus that employs the vehicle collision simulation method described above is also a subject of rights, and the apparatus is a mechanics composed of two mass points of a chest and a waist relating to a dummy placed on a vehicle seat. A model for creating a dynamic model composed of a waist belt, a shoulder belt with a force limiter, and a knee bolster to which a predetermined spring characteristic is imparted, relating to a restraint body including at least a seat belt for restraining the dummy to the seat And a mathematical formula that formulates the dynamic model into a chest motion equation that is the sole motion of the chest only and a waist motion equation that is the sole motion of the waist only, and the identification identified through a dummy thread test Substitute the spring characteristics of the dynamic model into the equations of motion and A simulation condition setting unit for setting a deceleration waveform, a solver unit for calculating a dummy behavior at the time of a vehicle collision according to the conditions set by the simulation condition setting unit, a deceleration characteristic diagram of a dummy component from the calculation result, and And an output unit that outputs at least one of the movement amount diagrams, and the solver unit regards the chest as a rotational motion around the waist and corrects the final deceleration of the chest. Of course, actions and effects described in the vehicle collision simulation program the vehicle collision simulation device was also described above can be obtained.
Other features and advantages of the present invention will become apparent from the following description of embodiments using the drawings.

  FIG. 1 shows functional blocks schematically showing the configuration of a vehicle collision simulation apparatus according to the present invention. As can be understood from this figure, the vehicle collision simulation apparatus includes a dummy dynamic model placed on a vehicle seat, a modeling unit 20 that creates a dynamic model of a restraint body that restrains the dummy on the seat, Formulating unit 30 for formulating a dynamic model using an equation of motion, substituting the spring characteristic of the dynamic model identified through a dummy thread test or a knee bolster compression test into the equation of motion, and collision deceleration characteristics to the vehicle model , A solver unit 50 for calculating the behavior of the dummy at the time of a vehicle collision according to the conditions set by the simulation condition setting unit 40, and the dummy component deceleration from the calculation result of the solver unit 50 An output unit 60 for outputting a characteristic diagram and a movement amount diagram is provided.

[Mechanical model]
FIG. 2 shows a dummy placed on the vehicle 1 assuming a frontal collision and a dynamic model of a restraint body that restrains the dummy on the seat 2. Here, the dummy model body 3 is composed of a waist element 3b and a chest element 3a that rotates around the waist element (including the knee portion), and the restraint model is a force as a seat belt 4. It comprises a shoulder belt element 4a with a limiter, a waist belt element 4b, and a knee bolster element 5. Such setting of modeling is performed directly by the modeling unit 20, or modeling data performed at another place is loaded into the modeling unit 20.

As apparent from FIG. 2, in the spring mass modeling, the chest element 3a has a mass: m ₁ , the waist element 3b has a mass: m ₂ , and the shoulder belt element 4a with a force limiter has a force limiter load: F _f and a spring coefficient: k ₀ , the waist belt element 4 b is represented by a spring coefficient: k ₁ , and the knee bolster element 5 is represented by a spring coefficient: k ₂ in the soft cushion area and an additional spring coefficient: k ₃ in the non-soft cushion area.

Here we define the meaning of the main symbols used in the following description;
m ₁ : Dummy chest mass
m ₂ : Dummy waist mass
k ₀ : Shoulder seat spring constant
k ₁ : waist belt spring constant
k ' ₂ ： Before bottom of knee bolster (soft cushion area) spring constant (knee equivalent)
k ' ₃ : After the bottom of the knee bolster (non-soft cushion region), the spring constant added to k' ₂ (knee equivalent)
k ₂ : Knee bolster bottom (soft cushion area) spring constant (waist conversion)
k ₃ : Spring constant added to k ₂ after bottom of knee bolster (non-soft cushion region) (converted to waist)
F _f : Shoulder belt force limiter load
L ₁ : Initial dimension from dummy knee to knee bolster
L ₂ : Initial dimension from knee to bottom position until bottom of knee bolster starts and k3 is activated
a: Sine wave amplitude of the vehicle body side forced excitation deceleration ω: Sine wave angular velocity of the vehicle body side forced excitation deceleration
T ₁ : End time of half-cycle sine wave forced excitation deceleration
T ₂ : Shoulder belt force limiter operation start time
X: Displacement of mass system
Y: Vehicle side displacement
_{A, B, C, D 1} ~D 3, X st: constant used during operation

  For the dummy mass and restraint spring mass model as shown in FIG. 2, the behavior of each mass part when the forced excitation deceleration of a half-cycle sine wave is applied to the vehicle 1 is as follows: chest deceleration, waist deceleration Is analyzed.

〔Equation of motion〕
In order to simplify the calculation, the first spring mass model limited to the chest element 3a and the shoulder belt element 4a as shown in FIG. 3 and the second spring mass model limited to the waist element 3b, the waist belt 4b and the knee bolster 4 as shown in FIG. Divide into spring mass models. First, the equation of motion is obtained using the first spring mass model.

が得られ、これが強制変位となる。これを図３で示したバネマスモデルに適用すると、

式(６)の右辺第1、2項は自由振動、第3項は強制振動の項となっている。そこで、

一方，式(５)の解をx₂(t)=Ｄ₃・tとすると、x₂(t)の２階微分は０となるので、
これを式(５)に代入すると、

が得られる。 If a forced excitation deceleration of a sine wave (vehicle displacement: second derivative of Y) is given to the vehicle body under the condition of 0 ≦ t ≦ T ₁ ,

Is obtained, which is the forced displacement. Applying this to the spring mass model shown in FIG.

The first and second terms on the right side of Equation (6) are free vibration and the third term is a forced vibration term. Therefore,

On the other hand, if the solution of equation (5) is x ₂ (t) = D ₃ · t, the second derivative of x ₂ (t) is 0.
Substituting this into equation (5) gives

Is obtained.

が得られる。
これにより、半周期正弦波の強制励振減速度が作用している時間領域と0≦t≦Ｔ₁とその後の時間領域t＞Ｔ₁での胸部の変位と減速度が演算できる。但し、この発明では、フォースリミッタ付きの肩ベルトを考慮しているので、つまりフォースリミッタ加重：Ｆ_fの存在を考慮しているので、前述した２つの領域での胸部の質量とその減速度の積がフォースリミッタ加重：Ｆ_fに到達した時間、すなわちフォースリミッタが作動開始する時間：Ｔ₂以降でいずれかの前記時間領域での胸部の質量とその減速度の積がフォースリミッタ加重：Ｆ_fに等しいものとし、衝突前の運動エネルギーを使い尽くした時点ではいずれかの前記時間領域での胸部の質量とその減速度の積が0になるように、その計算プログラムを組んでいる。 Next, in order to convert the forced excitation deceleration sine wave into a half-cycle sine wave, consider a time zone of t> T ₁ . Displacement of the chest before T ₁ : X is X _A , and after that is X _B ,

Is obtained.
Thereby, the displacement and deceleration of the chest can be calculated in the time domain in which the forced excitation deceleration of the half-cycle sine wave is applied, 0 ≦ t ≦ T _1, and the subsequent time domain t> T ₁ . However, in the present invention, since the shoulder belt with the force limiter is considered, that is, the presence of the force limiter weight: F _f is considered, the mass of the chest and the deceleration thereof in the two regions described above are considered. The time when the product reaches the force limiter weight: F _f , that is, the time when the force limiter starts to operate: the product of the chest mass and its deceleration in any of the time regions after T ₂ is the force limiter weight: F _f The calculation program is set so that the product of the chest mass and the deceleration in any one of the time domains becomes zero when the kinetic energy before the collision is used up.

以下胸部での解析と同じ方法でＸを求め，式(11)，(12)と同様に強制励振減速度の半周期正弦波条件を組合せれば，腰部の変位と減速度が求める式が得られる。 Next, using the second spring mass model limited to the waist element 3b, the waist belt 4b, and the knee bolster 4 shown in FIG. The forced excitation deceleration is the same as in equation (1), but the equation of motion is given by the three types of spring coefficients k ₁ , k ₂ , and k ₃ for the waist belt and knee bolster due to changes in the displacement of the waist. It becomes as follows.

Below, X is obtained by the same method as the analysis in the chest, and if the half-cycle sine wave conditions of forced excitation deceleration are combined in the same way as equations (11) and (12), the equation for calculating the waist displacement and deceleration is obtained. It is done.

となり、
水平方向の加速度と胸部の回転軸距離：Ｌ_cpの軸方向の減速度を直交軸に近似して計算すると，胸部合成減速度：Ａ_cは、

となる。なお腰部合成減速度は，計算モデルが並進運動のみとしているので、合成減速度は考慮する必要がなく、先の式で求められる値：ａ_pが腰減速度となる。 As described above, separate equations of motion have been established for analyzing the behavior at the time of the collision between the chest and the waist. However, in an actual dummy, the chest and the waist are connected and affect each other's motion. That is, since the chest causes a rotational motion around the waist, it is necessary to consider a vector sum for chest deceleration from such a viewpoint. At this time, it is possible to obtain the synthesis deceleration A _c of the chest from the vector relationship shown in FIG. Chest and lumbar decelerations at time t of the chest and lumbar that were independently exercised obtained from the above formulas are set as a _c and a _p , respectively, and the rotation axis distance of the chest, the line connecting the chest and waist center of gravity at time t The angle formed with the vertical line, the chest relative speed based on the waist, the chest deceleration due to the centripetal force generated by the rotational movement of the chest, and the deceleration transmitted to the chest due to the deceleration of the waist are respectively represented by L _cp , θ, υ _cp , a _c1 , A _c2

And
When the horizontal acceleration and the rotation axis distance of the chest: L _cp are calculated by approximating the axial deceleration to the orthogonal axis, the combined chest deceleration: _Ac is

It becomes. Note that the hip model deceleration is calculated only by the translational motion, so there is no need to consider the combined deceleration, and the value obtained by the above equation: _ap is the waist deceleration.

[Identification of spring characteristics, etc.]
Among the input parameters for performing the collision simulation, it is necessary to conduct experiments in advance to obtain values for the spring coefficient: k _{0 to} k ₃ and the force limiter weight: F _f . Here, the spring coefficients: k ₀ and k ₁ are determined by the elongation rate of the seat belt webbing and the specifications of the pretensioner, and are calculated by an actual thread test or a bench simulation test. FIGS. 6 and 7 show shoulder belt load-dummy displacement curves and hips when a sled test is performed under the same vehicle deceleration and arrangement conditions used in the comparison of experimental values and simulation calculated values described later. The measurement result of the belt load-dummy displacement curve and the straight line indicating the spring coefficient: k ₀ and k ₁ are shown. Since the shoulder belt restraining the shoulder portion is provided with a force limiter, it can be seen that the force limiter load: F _f is a value around 6 kN in the example of FIG.

On the other hand, the spring coefficients k ₂ and k ₃ representing the characteristics of the knee bolster are obtained by an impactor static compression test on the knee bolster. Using a compression tester, a hemispherical impactor with a diameter of 100 mm was created, simulating the projected area equivalent to two dummy knees (in this case, HybridIII) that will actually receive the load, and this was applied at a speed of 500 mm / min. The load-impactor displacement curve when pressed against the knee bolster is obtained. The knee bolster used for the measurement is a foamed PP bead having a thickness of 100 mm. FIG. 8 shows a schematic diagram of the measurement principle, and FIG. 9 shows the measurement result. Incidentally it is possible also inferred value of L ₂ -L ₁ of the knee bolster from FIG. However, the spring constants obtained approximately here are k ′ ₂ and (k ′ ₂ + k ′ ₃ ). Considering the dummy state as shown in FIG. 10, m ₃ is the dummy thigh mass, and m ₄ is the lower limb. If the partial mass (both left and right total values) is assumed, (m ₃ + m ₄ ) and m ₂ are assumed to have the same deceleration rate, and k ₂ and (k ′ ₂ + k ′ ₃ ) are m ₂ / ( The product of m ₂ + m ₃ + m ₄ ) is k ₂ and k ₂ + k ₃ . In reality, the spring constants: k _{0 to} k ₃ are non-linear values with respect to the displacement, but the spring constants used for simple calculation: k _{0 to} k ₃ are treated as linear values in order to simplify the calculation. .

[Comparison between experimental values and simulation values]
It was examined how well the result of the simple simulation calculation according to the present invention fits the result of the collision thread test using the dummy. The impact sled tester is well known and will not be described in detail here, but the tester used was hydraulic, and the steering and front head and chest protection airbags were removed. As the seat belt, a three-point continuous seat belt type having a pretensioner and a force limiter mechanism in the retractor was used. FIG. 11 shows a comparison graph between the forced excitation deceleration characteristic of the vehicle body side half-cycle sine wave used for the simulation calculation and the actual forced excitation deceleration characteristic reproduced by the sled test. From this figure, it can be understood that the forced excitation deceleration characteristic in the sled test can reproduce a waveform substantially equivalent to the forced excitation deceleration characteristic used in the simulation. Note that the amplitude and period of the vehicle body side deceleration characteristics used in this sled test are such that the vehicle body permanent deformation amount is 0.312 m after a vehicle with kinetic energy at a vehicle speed of 55 km / h before collision hits the fixed wall in an actual vehicle. However, if the forced excitation deceleration characteristic is a half-cycle sine wave, any vehicle crash characteristic can be calculated.

  The input parameters used in the simulation calculation during this comparison test are listed in FIG. FIGS. 13 to 16 show calculated values of the deceleration waveforms of the chest and the waist obtained by substituting such input parameters into the above-described equations and experimental values actually obtained by the thread test. FIG. 13 shows changes in waist deceleration with time, FIG. 14 shows changes in waist deceleration with respect to movement of the waist, FIG. 15 shows changes in chest deceleration with respect to time, and FIG. 16 shows changes in chest deceleration with respect to movement of the waist. Respectively. From the comparison of these experimental values and the calculated values, the impact simulation calculation according to the present invention is quite similar to the experimental results by the sled test, despite starting from a very simple modeling. With regard to the deceleration waveform of the chest, the behavior until reaching the peak value is in good agreement with the experimental value, and it is proved that this collision simulation technology can be used sufficiently for estimating the collision injury on the desk at the time of vehicle body design etc. Yes.

  The vehicle collision simulation technology according to the present invention is applied not only to automobiles that attempt to reduce occupant injuries by analyzing the behavior of passengers restrained by seats, but also to the field of vehicle design in general railways and other vehicles. Can do.

1 is a functional block diagram schematically showing the configuration of a vehicle collision simulation device according to the present invention. Explanatory drawing explaining the dynamic model of the dummy restrained by the vehicle and the vehicle Explanatory drawing explaining the mechanical model about the chest Explanatory drawing explaining the mechanical model about the waist Explanatory drawing explaining the coordinated movement between the waist and chest Graph showing the relationship between waist movement and shoulder belt load used to identify spring coefficient: k0 based on thread test Graph showing the relationship between waist movement and waist belt load used to identify spring coefficient: k1 based on thread test 原理 Principle of compression test グ ラ フ Graph showing the relationship between displacement and load used to identify the spring coefficient of knee bolster based on compression test Explanatory drawing explaining the interaction force which acts on a thigh, a leg part, and a waist | hip | lumbar part Comparison graph between forced excitation deceleration characteristics of car body side half-cycle sine wave used in simulation calculation and actual forced excitation deceleration characteristics reproduced by sled test List of input parameters Lumbar deceleration characteristics graph based on experimental and calculated values Lumbar deceleration characteristics graph based on experimental and calculated values Chest deceleration characteristics graph based on experimental and calculated values Chest deceleration characteristics graph based on experimental and calculated values

Explanation of symbols

1: Vehicle 2: Seat 3: Dummy model body 3a: Chest element 3b: Lumbar element 4: Seat belt 4a: Shoulder belt element 4b with force limiter: Lumbar belt element 5: Knee bolster element 20: Modeling unit 30: Formulating unit 40: Condition setting unit 50: Solver unit 60: Output unit

Claims (2)

A waist belt provided with predetermined spring characteristics relating to a dynamic model composed of two mass points of a chest and a waist relating to a dummy placed on a vehicle seat, and a restraint body including at least a seat belt for restraining the dummy to the seat And a mechanical model composed of a shoulder belt with force limiter and a knee bolster, a function that sets the chest motion equation as the sole motion of the chest alone and a lumbar motion equation as the sole motion of the waist, and a dummy thread test A function of substituting the spring characteristics of the dynamic model identified through the equations of motion into the equations of motion, a function of calculating a dummy behavior at the time of a vehicle collision by inputting a forced deceleration waveform to the vehicle, and the chest A function that corrects the final deceleration of the chest as if it were a rotational motion centered on the lower back, and Vehicle collision simulation program, characterized in that to execute a function of outputting at least one of the deceleration characteristic view and the movement amount diagram of the components, to the computer.   A waist belt provided with predetermined spring characteristics relating to a dynamic model composed of two mass points of a chest and a waist relating to a dummy placed on a vehicle seat, and a restraint body including at least a seat belt for restraining the dummy to the seat A modeling unit that creates a mechanical model composed of a shoulder belt with force limiter and a knee bolster, a thoracic motion equation in which the dynamic model is the sole motion of only the chest, and a lumbar motion in which the lumbar is a sole motion And a simulation condition setting unit for substituting the spring characteristics of the dynamic model identified through a dummy thread test into the equations of motion and setting a forced deceleration waveform to be input to the vehicle. And a dummy at the time of vehicle collision according to the conditions set by the simulation condition setting unit. A solver unit that calculates movement, and an output unit that outputs at least one of a deceleration characteristic diagram and a movement amount diagram of a dummy component from a calculation result of the solver unit, and the solver unit includes The vehicle collision simulation apparatus characterized in that the chest is regarded as a rotational motion centered on the waist and the final chest deceleration is corrected.

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