A method for formulating aPLI leg type performance targets

Abstract

A method for formulating the performance objectives of the aPLI leg type of the present invention includes the steps of: determining the primary performance objectives of the aPLI leg type, determining the secondary performance objectives of the aPLI leg type, evaluating the scores of the secondary performance objectives of the aPLI leg type, determining the tertiary performance objectives of the aPLI leg type, evaluating the scores of the tertiary performance objectives of the aPLI leg type, etc. For the performance of the aPLI leg type, performance evaluation is advanced to the concept stage, and through the performance of each level of the aPLI leg type, the objective formulation is carried out first and then the performance evaluation is carried out to confirm whether the target point can be achieved, ensuring the rationality and feasibility of the objective formulation, having the advantages of being both simple and systematic in operation, guiding the layout schemes of each structure in the front-end structure in the concept stage, greatly shortening the number of rounds of leg type performance optimization in the engineering analysis stage, and improving the passing rate of achieving the performance objectives of the aPLI leg type.

Description

Technical Field

[0001] The present invention relates to the field of collision performance prediction, and particularly to a method for formulating aPLI leg type performance targets. Background Art

[0002] For the aPLI leg type performance test, the vehicle is adjusted to a normal driving posture, and the leg type impacts the front leg type test area of the vehicle horizontally at a speed of 40 ± 0.72 km / h to evaluate the collision protection performance of the vehicle for the pedestrian's leg; at the moment of impact, the leg type should be in a free flight state, the velocity vector is in the horizontal plane and the vehicle longitudinal vertical plane, the angular deviation should not be greater than ±2°, the deviation of the leg type axis in the vehicle transverse vertical plane and the longitudinal vertical plane should not be greater than ±2°, the rotational angular deviation of the leg type around its vertical axis should not exceed ±2°, and the bottom of the leg type should be within the range of 25 mm ± 10 mm above the ground reference plane. During the test, 8 indicators such as the calf bending moment (4), the thigh bending moment (3), and the knee ligament extension MCL are collected during the collision process, as shown in the appendix Figure 1 to evaluate the collision protection performance of the vehicle for the pedestrian's leg.

[0003] The leg type impact points are marked on the upper bumper reference line at intervals of 100 mm from the intersection of the vehicle longitudinal center plane and the upper bumper reference line to both sides of the vehicle. This 100 mm distance should be measured horizontally in the vehicle transverse vertical plane until the edge of the leg type evaluation area; the marked points are called leg type impact points. When the distance between the outermost leg type impact point and the edge of the leg type evaluation area is greater than 50 mm, a leg type impact point should be added 50 mm outside the outermost leg type impact point, as shown in the appendix Figure 2 as shown.

[0004] The C-NCAP China New Car Assessment Program stipulates that the highest score for the primary target leg type performance is 5 points and the lowest score is 0 points. For the secondary target, the highest obtainable score for each impact point is 1.000 and the lowest obtainable score is 0.000. The obtainable score points * 5 / the total number of impact points = the score for a single impact point. The tertiary target includes the thigh bending moment value, the calf bending moment value, and the knee ligament elongation (MCL). Among them, the thigh bending moment includes 3 (F1 to F3), the highest obtainable score is 0.400 points, and the largest F max is selected for scoring; the calf bending moment includes 4 (T1 to T4), the highest obtainable score is 0.400 points, and the largest T maxScoring is carried out; the maximum score for the knee ligament elongation (MCL) is 0.200 points, and the scoring is based on the MCL value. The score for a single evaluation index = (score for a single evaluation index * 5) / total number of impact points = score for a single evaluation index at a single impact point. When scoring, high-performance limits and low-performance limits are used for calculation. The low-performance limit and high-performance limit correspond to 0.000 points and the maximum achievable score respectively. For measured values between the two, linear interpolation is used for calculation, and rounding is used to retain three decimal places. The sum of the scores for single impact points obtained from the test is divided by the sum of the maximum achievable scores for these impact points to obtain the percentage score for the leg shape test area; the percentage is multiplied by the total score of 5 for the leg shape test area to obtain the final score for the first-level target leg shape test area, and this score is rounded to three decimal places. The low-performance limits for the thigh bending moment value, calf bending moment value, and knee ligament elongation are 440 Nm, 320 Nm, and 32 mm respectively, and the high-performance limits are 390 Nm, 275 Nm, and 27 mm respectively.

[0005] Since aPLI is used for the first time in China, and the pedestrian protection leg shape performance has always been developed based on the Flex-PLI leg shape during the vehicle model R & D of domestic automobile factories, the overall mass of the aPLI leg shape has been upgraded from 13.2 kg of the Flex-PLI leg shape to 24.7 kg, with an increase of 11.5 kg in the upper part for the hip mass. As a result, there are significant differences in the deformation modes of the aPLI leg shape and the flexible leg shape during impact with the vehicle, mainly in sedan models. The deformation postures and injury value evaluations of the two leg shapes show completely different forms; in the current industry development, only when the analysis conditions are available in the engineering stage can the performance development means of the aPLI leg shape with detailed evaluation be carried out. Summary of the Invention

[0006] In view of the problems existing in the prior art, the present invention conceives a method for formulating aPLI leg shape performance targets, formulates aPLI leg shape performance targets in the concept stage of vehicle model R & D, and decomposes the targets into first, second, and third-level targets, and adjusts and controls them during the project R & D process.

[0007] The technical solution to realize the present invention is: a method for formulating aPLI leg shape performance targets, characterized in that in the concept stage of vehicle model R & D, formulating aPLI leg shape performance targets, including the following steps:

[0008] 1) Determine the first-level target of aPLI leg shape performance:

[0009] 1.1) Set the target value A of the height of the front edge reference line of the engine hood to 920 mm, and the target value B of the lower reference line of the bumper to 260 mm;

[0010] 1.2) For sedan models, the height of the leading edge reference line of the engine hood ≤ target value A, and the height of the lower reference line of the bumper ≤ target value B; for SUV models, the height of the leading edge reference line of the engine hood ≥ target value A, and the height of the lower reference line of the bumper ≥ target value B, or the height of the leading edge reference line of the engine hood ≥ target value A, and the height of the lower reference line of the bumper ≤ target value B;

[0011] 1.3) Determine the vehicle model according to step 1.2). The primary target for sedan models is that the total score of the aPLI leg performance is 3.5 - 4.5 points, and the primary target for SUV models is that the total score of the aPLI leg performance is 4.5 - 5 points;

[0012] 2) Determine the secondary target of aPLI leg performance:

[0013] The secondary target of aPLI leg performance is the score of the available points for a single impact point p in the aPLI leg performance test area of the vehicle model determined in step 1). p is the p-th leg impact point from the left to the right of the front bumper. The pedestrian protection leg test area is divided according to the styling CAS data and the vehicle body layout data. The primary target is decomposed according to the number of leg impact points in the test area, and at the same time, the target is decomposed in combination with the results of the aPLI leg test database to obtain the score of the available points for the leg at a single impact point;

[0014] 3) Evaluate the score of the secondary target of aPLI leg performance:

[0015] Further score evaluation is carried out according to the range intervals of the styling characteristic parameters: the distance C from the Z - direction height of the calf support structure to the ground reference line, the X - direction distance D between the lower skirt styling and the front - most end of the front bumper mask, and the X - direction distance E between the hood seam and the front - most end of the front bumper mask. When the values of C, D, and E are in different range intervals, they correspond to different available point scores. It can be obtained through the accumulation of test vehicle model data. The final total score is evaluated according to the secondary target. Determine whether it can be achieved. If not, return to step 2) to re - adjust the secondary target or adjust the styling characteristic parameters. If it can be achieved, evaluate the score of the tertiary target of aPLI leg performance;

[0016] 4) Determine the tertiary target of aPLI leg performance:

[0017] The tertiary target of aPLI leg performance is the scores of the three leg evaluation indicators of a single impact point that passed the evaluation in step 4): the thigh bending moment value F max 、the calf bending moment value T max and the knee ligament elongation (MCL). The tertiary target decomposition is formulated in combination with the results of the aPLI leg test database;

[0018] 5) Evaluate the score of the tertiary target of aPLI leg performance:

[0019] In step 1.2) for determining the front-end structure of the vehicle model, components that affect the aPLI leg-form performance are included. The performance impact of each component on one of the three evaluation indicators of the leg-form three-level target can be defined as 1 impact coefficient. For different impact regions, the impact coefficient of the thigh bending moment value F max is defined as a 1 , the impact coefficient of the elongation of the knee ligament MCL is defined as a 2 , and the impact coefficient of the calf bending moment value T max is defined as a 3 . The impact coefficients of other components are respectively defined as b 1 , b 2 , b 3 , c 1 , c 2 , c 3 , d 1 , d 2 , d 3 , e 1 , e 2 , e 3 , f 1 , f 2 , f 3 , g 1 , g 2 , g 3 . The impact coefficient value is obtained based on the energy absorption space F range. The three-level target score of the aPLI leg-form performance is compared with the three-level evaluation score to determine whether the target can be achieved. If not, return to step 4) to readjust the three-level target or the impact structure. If the target is achieved, the aPLI leg-form performance target is qualified.

[0020] Preferably, in step 1.3), the first-level target for the sedan vehicle model is that the total score of the aPLI leg-form performance is 4 points, and the first-level target for the SUV vehicle model is that the total score of the aPLI leg-form performance is 4.8 points.

[0021] Preferably, in step 2), within the aPLI leg-form performance test area, the number of leg-form impact points is 15. On the upper bumper reference line, starting from the intersection of the vehicle longitudinal center plane and the upper bumper reference line, marks are made every 100 mm on both sides of the vehicle. The points are respectively L_7, L_6, L_5, L_4, L_3, L_2, L_1, L_0, L_-1, L_-2, L_-3, L_-4, L_-5, L_-6, L_-7.

[0022] The beneficial effects of the aPLI leg-form performance target setting method of the present invention are reflected in:

[0023] A method for formulating the performance objectives of the aPLI leg type enables the performance evaluation of the aPLI leg type to be advanced to the concept stage. Moreover, through the performance of the aPLI leg type at all levels, the objective formulation is carried out first, followed by the performance evaluation to confirm whether the target points can be achieved, ensuring the rationality and feasibility of the objective formulation. Therefore, this system and method have the advantages of being both simple and systematic in operation, can guide the layout schemes of various structures in the front-end structure at the concept stage, and greatly shorten the number of rounds of leg type performance optimization in the engineering analysis stage, improving the passing rate of achieving the performance objectives of the aPLI leg type. Description of the Drawings

[0024] Figure 1 It is a schematic diagram of the aPLI leg type bumper structure;

[0025] Figure 2 It is a schematic diagram of the distribution of leg type impact points;

[0026] Figure 3 It is a reference line diagram of the leading edge of the engine hood;

[0027] Figure 4 It is a reference line diagram of the lower part of the bumper (LBRL);

[0028] Figure 5 It is a flowchart of a method for formulating the performance objectives of the aPLI leg type;

[0029] Figure 6 It is a schematic diagram of styling feature parameters. Detailed Implementation Modes

[0030] The following further elaborates on the present invention in conjunction with Figure 2 —6 and specific embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0031] Table 1 Example of the relationship between the energy absorption space F in the x-direction of the hard point and the influence coefficient

[0032]

[0033]

[0034] As shown in the attached Figure 5As shown in the figure, a method for formulating the performance objectives of the aPLI leg type. The primary objective is the total score L of the aPLI leg type performance, and appropriate objectives are formulated according to different vehicle models. The secondary objective is the score of a single impact point within the aPLI leg type performance test area. p is the p-th leg type impact point from the left to the right of the front bumper. The pedestrian protection leg type test area is divided based on the styling CAS data and vehicle body layout data. The primary objective is decomposed according to the number of leg type impact points within the test area, and at the same time, combined with the results of the aPLI leg type test database, the leg type score of a single impact point is obtained. The secondary objective needs to be evaluated based on the styling characteristic parameters to determine whether it can be achieved. If not, the secondary objective or the styling characteristic parameters need to be adjusted. The tertiary objective is the score objectives of the three evaluation indicators of the leg type at a single impact point, namely the thigh bending moment value F max , the calf bending moment value T max and the knee ligament elongation (MCL). They respectively represent the score of the thigh bending moment value F max at a single point, the score of the knee ligament elongation (MCL) at a single point, and the calf bending moment value T max score at a single point. The decomposition of the tertiary objective needs to be formulated in combination with the results of the aPLI leg type test database. The evaluation of the tertiary score needs to be evaluated based on each equipment structure, and the score is corrected using the influence coefficient. There are multiple components in the front-end structure of the vehicle model that affect the aPLI leg type performance. The performance impact of each component on one of the three evaluation indicators of the leg type tertiary objective can be defined as 1 influence coefficient. For different influence areas, the influence coefficient affecting the thigh bending moment value F max is defined as a 1 , the influence coefficient affecting the knee ligament elongation MCL is defined as a 2 , and the influence coefficient affecting the calf bending moment value T max is defined as a 3 ; The evaluation of the tertiary score is compared with the tertiary objective to determine whether the objective can be achieved. If not, the tertiary objective or the influencing structure needs to be adjusted.

[0035]

[0036] N 1 =F max ×a 1 ×b 1 ×c 1 ×d 1 ×e 1 ×f 1 ×g 1

[0037] N 2 =MCL×a 2 ×b 2 ×c 2 ×d 2 ×e 2×f 2 ×g 2

[0038] N 3 = T max ×a 3 ×b 3 ×c 3 ×d 3 ×e 3 ×f 3 ×g 3

[0039]

[0040] Description:

[0041] L - Primary target score

[0042] x - Total number of leg impact points

[0043] Mp - Secondary target score

[0044] p - The pth leg impact point from the left to the right of the front bumper

[0045] Nq - Tertiary target score, q ranges from 1 to 3

[0046] N 1 - Thigh bending moment value F at a single point max Score

[0047] N 2 - Score of the elongation of the knee ligament (MCL) at a single point

[0048] N 3 - Calf bending moment value T at a single point max Score

[0049] Example 1:

[0050] Formulation of aPLI leg performance targets for SUV model a

[0051] Formulation of primary targets:

[0052] Input requirements: The target value A is defined as 920, and the target value B is defined as 260 mm, as shown in the appendix Figure 3-4 as shown

[0053] Measured values: The height of the reference line at the front edge of the engine hood of a certain model is 1050, and the height of the reference line at the lower part of the bumper is 325 mm

[0054] Conclusion: The vehicle model meets the requirements that the height of the leading edge reference line of the engine hood is 1050 mm > target value A (920 mm), and the height of the lower reference line of the bumper is 325 mm > target value B (260 mm). It is determined that this vehicle model is an SUV model, as shown in the attachment. Figure 2-4 as shown.

[0055] Formulation of primary targets: The primary targets for SUV models are defined as 4.5 - 5 points.

[0056] Formulation of secondary targets:

[0057] Measured value: The number of leg impact points is 15, as shown in the attachment. Figure 2 as shown.

[0058]

[0059] Secondary score evaluation:

[0060] Input requirements: C value = 330 mm, D value = 50 mm, E value = 40 mm, refer to the attachment. Figure 6 as shown.

[0061] It is formulated by combining the results of the aPLI leg test database.

[0062] For example, at point L1, C < 330 mm, D < 50 mm, E < 40 mm, the aPLI leg can get 1 point; at point L5, 330 mm < C < 350 mm, D > 50 mm, E < 40 mm, the aPLI leg can get 0.8 points.

[0063] Position L_7 L_6 L_5 L_4 L_3 L_2 L_1 L_0 L_-1 L_-2 L_-3 L_-4 L_-5 L_-6 L_-7 C 340 340 340 325 325 325 325 325 325 325 325 325 340 340 340 D 60 55 55 45 20 20 20 20 20 20 20 45 55 55 60 E 30 33 35 40 40 40 40 40 40 40 40 40 35 33 30 Available score points 0.9 0.9 0.8 0.9 1 1 1 1 1 1 1 0.9 0.8 0.9 0.9

[0064] Secondary score evaluation: (Sum of obtainable points / Number of impact points) * 5 = (14 / 15) * 5 = 4.666 points

[0065] Conclusion: The secondary score evaluation of 4.666 points meets the secondary target of 4.5 - 5 points.

[0066] Formulation of tertiary targets:

[0067] It is formulated by combining the results of the aPLI leg test database.

[0068] Position L_7 L_6 L_5 L_4 L_3 L_2 L_1 L_0 L_-1 L_-2 L_-3 L_-4 L_-5 L_-6 L_-7 <![CDATA[F max > 0.4 0.4 0.3 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.3 0.4 0.4 MCL 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 <![CDATA[T max > 0.3 0.3 0.3 0.3 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.3 0.3 0.3 0.3 Available score points 0.9 0.9 0.8 0.9 1 1 1 1 1 1 1 0.9 0.8 0.9 0.9

[0069] Tertiary score evaluation:

[0070] Structural status: There is a millimeter-wave radar and a sign at the position of point L_0. The x-direction energy absorption space of the millimeter-wave radar is 102 mm, which affects the calf bending moment value T max and the x-direction energy absorption space of the sign is 92 mm, which affects the thigh bending moment value F maxThere are position lights at the L_±4 and L_±5 points. The x-direction energy absorption space of the position lights is at least 85 mm in the thigh bending moment area, which affects the thigh bending moment value F max The x-direction energy absorption space of the position lights is at least 65 mm in the knee ligament elongation area, which affects the knee ligament elongation MCL. It can be seen from the example of the relationship between the x-direction energy absorption space F of the hard points in Table 1 and the influence coefficient that the influence coefficient a of the millimeter-wave radar 3 = 1, marking the influence coefficient c 1 = 0.9, and the affected position is the L0 point. The influence coefficient e of the position light 1 = 0.8, e 2 = 0.6, and the affected positions are the L_±4 and L_±5 points. The corrected scores are as follows in the table.

[0071]

[0072] Three-level score evaluation: (sum of available points / number of impact points) * 5 = (13.36 / 15) * 5 = 4.453 points. Conclusion: The three-level score evaluation of 4.453 points does not meet the three-level target of 4.5 points to 5 points. It is necessary to adjust the energy absorption space to improve the total score. Adjustment measures: The minimum size of the x-direction energy absorption space of the position lights in the thigh bending moment area is adjusted from 85 mm to 90.5 mm, then the influence coefficient e of the position light 1 = 0.9, and the scores after adjustment are as follows in the table.

[0073]

[0074]

[0075] Three-level score evaluation after adjustment: (sum of available points / number of impact points) * 5 = (13.5 / 15) * 5 = 4.5 points

[0076] Conclusion: The three-level score evaluation of 4.5 points after adjustment meets the three-level target of 4.5 points to 5 points.

[0077] The aPLI leg type performance target for this SUV model is formulated.

[0078] Example 2:

[0079] Formulation of aPLI leg type performance target for a sedan model

[0080] Formulation of primary target:

[0081] Input requirements: The target value A is defined as 920 mm, and the target value B is defined as 260 mm.

[0082] Measured values: The height of the reference line at the front edge of the engine hood of a certain model is 850 mm, and the height of the reference line at the lower part of the bumper is 253 mm.

[0083] Conclusion: For this vehicle model, the height of the leading edge reference line of the engine hood is 850 mm < target value A (920 mm), and the height of the lower reference line of the bumper is 253 mm < target value B (260 mm). It is determined that this vehicle model is a sedan, as shown in the appendix Figure 2-4 as shown.

[0084] Formulation of primary targets: The primary targets for the sedan vehicle model are defined as 3.5 - 4.5 points.

[0085] Formulation of secondary targets:

[0086] Measured values: The number of leg impact points is 15, as shown in the appendix Figure 2 as shown.

[0087]

[0088] Secondary score evaluation:

[0089] Input requirements: C value = 260 mm, D value = 20 mm, E value = 100 mm, as shown in the appendix Figure 6 as shown.

[0090] It is formulated in combination with the results of the aPLI leg test database.

[0091] For example, at point L1, C < 260 mm, D > 20 mm, E > 100 mm, the aPLI leg can get 1 point; at point L5, C < 260 mm, 10 mm < D < 20 mm, E < 70 mm, the aPLI leg can get 0.7 point.

[0092] Position L_7 L_6 L_5 L_4 L_3 L_2 L_1 L_0 L_-1 L_-2 L_-3 L_-4 L_-5 L_-6 L_-7 C 250 250 250 255 255 255 255 255 255 255 255 255 250 250 250 D 14 16 18 20 20 22 22 22 22 22 20 20 18 16 14 E 50 60 70 90 115 115 115 120 115 115 115 90 70 60 50 Available score points 0.8 0.7 0.7 0.9 1 1 1 1 1 1 1 0.9 0.7 0.7 0.8

[0093] Secondary score evaluation: (Sum of available points / Number of impact points) * 5 = (13.2 / 15) * 5 = 4.4 points

[0094] Conclusion: The secondary score evaluation is 4.4 points, meeting the secondary target of 3.5 - 4.5 points.

[0095] Formulation of tertiary targets:

[0096] It is formulated in combination with the results of the aPLI leg test database.

[0097]

[0098] Tertiary score evaluation: Structural status: There is a marked trim at the position of point L_0, and the x - direction energy absorption space is 72 mm, affecting the thigh bending moment value F max . There is a millimeter - wave radar at the position of point L_3, and the x - direction energy absorption space of the millimeter - wave radar is 82 mm, affecting the calf bending moment value T max。There are lidar sensors at the L_±5 and L_±6 positions. The minimum energy absorption space of the lidar sensor in the x-direction in the thigh bending moment area is 65 mm, which affects the calf bending moment value T max 。

[0099] From the example of the relationship between the energy absorption space F in the x-direction of the hard points in Table 1 and the influence coefficient, it can be seen that the influence coefficient c of the logo trim 1 = 0.7, and the affected position is point L0. The influence coefficient a of the millimeter-wave radar 3 = 0.8, and the affected position is point L_3. The influence coefficient b of the lidar 3 = 0.6, and the affected positions are L_±5 and L_±6. The corrected scores are shown in the following table.

[0100]

[0101] Three-level score evaluation: (Sum of available points / Number of impact points) * 5 = (12.6 / 15) * 5 = 4.2 points

[0102] Conclusion: The three-level score evaluation of 4.2 points meets the three-level target of 3.5 - 4.5 points.

[0103] The performance target setting of the aPLI leg type for this car model is completed.

[0104] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for formulating the performance target of the aPLI leg type, characterized in that, in the concept stage of vehicle model R & D, formulate the performance target of the aPLI leg type, including the following steps: 1) Determine the primary performance target of the aPLI leg type: 1.1) Set the target value A of the height of the reference line at the front edge of the engine hood as 920 mm, and the target value B of the reference line at the lower part of the bumper as 260 mm; 1.2) For sedan models, the height of the reference line at the front edge of the engine hood ≤ target value A, and the height of the reference line at the lower part of the bumper ≤ target value B; for SUV models, the height of the reference line at the front edge of the engine hood ≥ target value A, and the height of the reference line at the lower part of the bumper ≥ target value B, or the height of the reference line at the front edge of the engine hood ≥ target value A, and the height of the reference line at the lower part of the bumper ≤ target value B; 1.3) According to the vehicle model determined in step 1.2), the primary target for sedan models is that the total score of the aPLI leg type performance is 3.5 - 4.5 points, and the primary target for SUV models is that the total score of the aPLI leg type performance is 4.5 - 5 points; 2) Determine the secondary performance target of the aPLI leg type: The secondary performance target of the aPLI leg type is the score that can be obtained for a single impact point p in the aPLI leg type performance test area of the vehicle model determined in step 1). p is the p-th leg type impact point from the left side to the right side of the front bumper. Divide the pedestrian protection leg type test area according to the styling CAS data and the vehicle body layout data, decompose the primary target according to the number of leg type impact points in the test area, and at the same time combine the results of the aPLI leg type test database to perform target decomposition to obtain the score that can be obtained for the leg type of a single impact point; 3) Evaluate the score of the secondary performance target of the aPLI leg type: According to the styling characteristic parameters: the distance C of the Z - direction height of the calf support structure from the ground reference line, the X - direction distance D between the lower skirt styling and the front - most end of the front bumper mask, and the X - direction distance E between the hood seam and the front - most end of the front bumper mask, conduct further score evaluation. When the values of C, D, and E are in different range intervals, they correspond to different scores that can be obtained. It can be obtained through the accumulation of test vehicle model data. Evaluate the final total score according to the secondary target. Determine whether it can be achieved. If not, return to step 2) to readjust the secondary target or adjust the styling characteristic parameters. If it can be achieved, conduct the score evaluation of the tertiary performance target of the aPLI leg type; 4) Determine the tertiary performance target of the aPLI leg type: The three - level target of the aPLI leg - type performance is the three evaluation indexes of the leg type for a single impact point passed in step 4): the thigh bending moment value F max , the calf bending moment value T max and the score of the knee ligament elongation (MCL). The three - level target is formulated by combining the results of the aPLI leg - type test database; 5) Evaluate the score of the tertiary performance target of the aPLI leg type: In step 1.2) for determining the front-end structure of the vehicle model, components that affect the aPLI leg form performance are included. The performance impact of each component on one of the three evaluation indicators of the three-level leg form target is defined as 1 impact coefficient. For different impact areas, the impact coefficient for affecting the thigh bending moment value F max is defined as a 1 , the impact coefficient for affecting the elongation of the knee ligament MCL is defined as a 2 , the impact coefficient for affecting the calf bending moment value T max is defined as a 3 , and the impact coefficients of other components are respectively defined as b 1 , b 2 , b 3 , c 1 , c 2 , c 3 , d 1 , d 2 , d 3 , e 1 , e 2 , e 3 , f 1 , f 2 , f 3、 g 1 , g 2 , g 3 . The impact coefficient value is obtained based on the energy absorption space F range. The three-level target score of the aPLI leg form performance is compared with the three-level evaluation score to determine whether the target can be achieved. If not, return to step 4) to re-adjust the three-level target or the impact structure. If the target is achieved, the aPLI leg form performance target is qualified.

2. A method for formulating the performance target of the aPLI leg type according to claim 1, characterized in that, in step 1.3), the primary target for sedan models is that the total score of the aPLI leg type performance is 4 points, and the primary target for SUV models is that the total score of the aPLI leg type performance is 4.8 points.

3. A method for formulating the performance target of the aPLI leg type according to claim 1, characterized in that, In step 2), within the aPLI leg type performance test area, the number of leg type impact points is 15. On the upper bumper reference line, starting from the intersection of the vehicle longitudinal center plane and the upper bumper reference line, marks are made every 100 mm on both sides of the vehicle. The points are taken as L_7, L_6, L_5, L_4, L_3, L_2, L_1, L_0, L_-1, L_-2, L_-3, L_-4, L_-5, L_-6, and L_-7 respectively.

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