Bumper skin low-speed impact experiment method and device and reduction degree evaluation method

Abstract

The invention relates to the technical field of part testing, in particular to a bumper skin low-speed impact experiment method and device and a reduction degree evaluation method. The test method comprises the following steps: placing a bumper skin to be tested on a platform through a tool; the position of the platform is adjusted so that the foremost end of the bumper skin to be detected can be tightly attached to the head of a collider; the position of the platform is fixed; controlling the collider to collide with the bumper skin to be tested at a set impact speed; in the impact process and after the impact process, recording experimental data; and adjusting the mass of the platform, and returning to the step of controlling the collider to collide with the bumper skin to be tested at the set impact speed to obtain experimental data under different masses. According to the invention, the independent experiment of the skin is realized, the whole bumper system does not need to be built, the cost is reduced, and the research and development period is shortened.

Description

Technical Field

[0001] This application relates to the field of component testing technology, and more specifically, to a method, apparatus, and method for evaluating the degree of impact of a bumper skin at low speed. Background Technology

[0002] OEMs often invest more in the research and development and verification of key automotive components. For example, car bumpers, as front and rear protective devices, can absorb and disperse the impact force when a collision occurs, reducing damage to the vehicle and passengers, maximizing the safety of occupants, and reducing car repair costs.

[0003] Modern car bumper designs increasingly prioritize pedestrian protection, employing specialized structures and materials to reduce injuries sustained during collisions. For component manufacturers producing bumper skins, performance verification often requires designing a specific trolley for a particular product or installing it on a complete vehicle as a full bumper system for testing. This increases both the testing cycle and R&D costs.

[0004] Currently, the common experimental method for low-speed impact is to install the entire bumper system (skin, energy-absorbing blocks, anti-collision beams, front-end modules, etc.) on a trolley or vehicle through welding, riveting and other processes for testing. This greatly increases the verification cost for bumper skin manufacturers and is not conducive to product development.

[0005] In view of the above, this application is hereby submitted. Summary of the Invention

[0006] The purpose of this application is to provide a low-speed impact testing method, apparatus, and reduction accuracy evaluation method for bumper skin. This application enables separate testing of the skin, eliminating the need to build the entire bumper system, which helps reduce costs and shorten the development cycle.

[0007] To achieve the above objectives, this application adopts the following technical solution: Firstly, this application provides a low-speed impact test method for bumper skin, including: The bumper skin to be tested is placed on the platform using a tooling. Adjust the position of the platform so that the foremost edge of the bumper skin to be tested is in close contact with the head of the collider; fix the position of the platform; The collider is controlled to collide with the bumper skin under test at a set impact speed; During and after the impact, experimental data are recorded; the experimental data includes at least: the scratch width, dent depth, pre- and post-collision photogrammetric vectors, impact force, and collision time of the bumper skin under test; Adjust the mass of the platform, return to the step of controlling the collider to collide with the bumper skin under test at a set impact speed, and obtain experimental data under different masses.

[0008] Secondly, this application provides a low-speed impact testing device for bumper skin, comprising: Tooling used to secure the bumper skin to be tested; Platform for placing the bumper skin; A collider is used to impact the bumper skin under test at a set impact speed. The data acquisition device is used to record experimental data during and after the impact process. The experimental data includes at least: the scratch width, dent depth, pre- and post-collision photogrammetric vectors, impact force, and collision time of the bumper skin under test; The platform includes a lower load-bearing layer and an upper cargo-carrying layer; The loading layer includes a groove, which is a loading area; The two sides of the loading layer are equipped with lifting devices to adjust the height of the loading layer to simulate different collision heights; The carrier layer is used to place the bumper skin to be tested.

[0009] Thirdly, this application provides a method for evaluating the reproducibility of a low-speed impact test on a bumper skin, which uses the low-speed impact test method on the bumper skin to obtain experimental data under different masses; The method for evaluating the replicability of the low-speed impact test on the bumper skin includes: Determine the trend of change in experimental data; The aforementioned trend of change is compared with the change characteristics of the bumper skin on the actual vehicle; The accuracy of the low-speed impact test on the bumper skin was evaluated based on the comparison results.

[0010] Compared with the prior art, the beneficial effects of this application are as follows: This embodiment of the application mounts the bumper skin onto an adaptable fixture (eliminating the need for front-end protection devices such as anti-collision beams), and then places the entire assembly on a movable and liftable platform (replacing the entire vehicle or trolley). By adding counterweights, low-speed impact tests can be conducted to achieve vehicle-level conditions, and the feasibility of this method is verified using professional photogrammetric deformation analysis. This embodiment enables separate testing of the skin, eliminating the need to build the entire bumper system, which helps reduce costs and shorten the development cycle. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0012] Figure 1 This is a flowchart of a low-speed impact test method for a bumper skin provided in an embodiment of this application; Figure 2 This is a schematic diagram of the tooling provided in the embodiments of this application; Figure 3 This is a schematic diagram showing the front end of the bumper skin closely attached to the head of the collider, as provided in this embodiment of the application. Figure 4 This is a schematic diagram of the platform structure provided in the embodiments of this application; Figure 5 This is a flowchart illustrating the method for evaluating the reproducibility of a low-speed impact test on a bumper skin, as provided in an embodiment of this application. Figure 6 This is the first curve showing the change in scratch width of the bumper skin after a low-speed impact as a function of mass, provided in the embodiments of this application. Figure 7 This is a second curve showing the change in dent depth of the bumper skin after a low-speed impact as a function of mass, provided in an embodiment of this application. Figure 8 This is a photogrammetric vector diagram of the entire impact state provided in the embodiments of this application; Figure 9 This is a photogrammetric vector diagram of the X-direction (perpendicular to the paper and outward) after impact, provided in an embodiment of this application. Figure 10 This is the third curve showing the change of impact force with mass during low-speed impact of the bumper skin provided in the embodiments of this application; Figure 11 This is the fourth curve showing the change in collision time versus mass during a low-speed impact on the bumper skin provided in this application embodiment; Among them, 1-distance measuring device installation point, 2-lower fixing point of bumper skin, 3-upper fixing point of bumper skin, 4-fixing point of bumper skin bracket, 5-skin, 6-collision device, 7-load-bearing layer, 8-carrying layer, 9-universal wheel, 10-lifting device. Detailed Implementation

[0013] The following description, in conjunction with the accompanying drawings, illustrates exemplary embodiments of this application, including various details to aid understanding. These should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0014] The present application will be further described in detail below with reference to the embodiments.

[0015] Figure 1 This is a flowchart illustrating a low-speed impact test method for a bumper skin according to an embodiment of this application. This embodiment is applicable to scenarios where a low-speed impact test is conducted individually on the bumper skin of a vehicle. See also... Figure 1 The method provided in this embodiment includes: S110. Place the bumper skin to be tested onto the platform using a tooling device.

[0016] The tooling is used to fix the bumper skin to be tested. Figure 2 This is a schematic diagram of the tooling provided in the embodiments of this application. The tooling is made of aluminum profiles and high-strength steel. The connection between the tooling and the skin is adjustable, allowing for corresponding adjustments according to the shape of the skin, which greatly saves experimental costs. Figure 2 The tooling is shown in four key parts: distance measuring device mounting point 1, lower bumper skin fixing point 2, upper bumper skin fixing point 3, and bumper skin bracket fixing point 4. Distance measuring device mounting point 1 is used to mount the distance measuring device for measuring the depth of the bumper skin's indentation. Lower bumper skin fixing point 2 is used to mount the lower part of the bumper skin, upper bumper skin fixing point 3 is used to mount the upper part of the bumper skin, and bumper skin bracket fixing point 4 is used to secure the entire tooling to the platform.

[0017] A platform is used to hold the bumper skin (along with tooling). The structure of the platform will be described in the following embodiments.

[0018] S120. Adjust the position of the platform so that the foremost edge of the bumper skin to be tested is in close contact with the head of the collider; fix the position of the platform.

[0019] The collider has a mass of 2000 kg and is equipped with an acceleration sensor, a displacement sensor, a trigger sensor, and an impact force sensor. The sensors need to be calibrated before the experiment.

[0020] The height of the platform should be calibrated so that it is 100mm above the horizontal ground.

[0021] Markers were affixed to the preset measurement points on the skin, and a photogrammetry system was set up to take pictures of the skin before the experiment.

[0022] For example, a photogrammetry system (CANON EOS-1DX, GOM Metrology) was used to measure the deformation of the bumper skin. Photogrammetry markers were sequentially attached outwards from the center of the impact, ensuring that the markers covered the impact area. Photogrammetry images were then taken before low-speed impact, after 450kg impact, 550kg impact, 650kg impact, and 750kg impact. The photogrammetry results for 450kg, 550kg, 650kg, and 750kg were calculated, and the deformation was calculated in the combined vector direction and X direction.

[0023] Install the tooling onto the platform, place a certain counterweight on the platform, and adjust the platform height so that the foremost edge of the bumper skin is 445mm from the ground; see [link / reference] Figure 3 Adjust the height of the collider 6 so that its head is 445mm from the ground; adjust the position of the platform so that the front end of the bumper skin 5 is close to the head of the collider 6; adjust the position of the platform's casters and lock the direction.

[0024] S130, Control the collider to collide with the bumper skin under test at a set impact speed.

[0025] Adjust the angle between the collider and the vertical plane so that the linear velocity of the collider is 4 km / h when it is at its lowest position above the horizontal plane.

[0026] Pull the impactor up at a certain angle to achieve an impact speed of 4–4.25 km / h, then release the impactor to complete the bumper skin impact test.

[0027] S140. Record experimental data during and after the impact; the experimental data shall include at least: the scratch width, dent depth, pre- and post-collision photogrammetric vectors, impact force and collision time of the bumper skin to be tested.

[0028] After the experiment, record the condition of the bumper skin, observe for any damage or breakage and any defects that affect the product's performance, and record the data collected by the sensors; conduct photogrammetry after the impact test and analyze the results.

[0029] S150. Adjust the mass of the platform, return to the step of controlling the collider to collide with the bumper skin under test at a set impact speed, and obtain experimental data under different masses.

[0030] Increase or decrease the counterweight on the platform to control the mass of the entire system to 450kg, 550kg, 650kg or 750kg, and continue the impact test.

[0031] This embodiment of the application mounts the bumper skin onto an adaptable fixture (eliminating the need for front-end protection devices such as anti-collision beams), and then places the entire assembly on a movable and liftable platform (replacing the entire vehicle or trolley). By adding counterweights, low-speed impact tests can be conducted to achieve vehicle-level conditions, and the feasibility of this method is verified using professional photogrammetric deformation analysis. This embodiment enables separate testing of the skin, eliminating the need to build the entire bumper system, which helps reduce costs and shorten the development cycle.

[0032] This application also provides a low-speed impact testing device for bumper skin, including: tooling, a movable and liftable platform, a collider, and a data collection device. Each component is described in detail below: The fixture is used to secure the bumper skin to be tested. See [link / reference]. Figure 2 A collider is used to impact the bumper skin under test at a set impact speed. A data acquisition device is used to record experimental data during and after the impact, including at least: the scratch width, dent depth, photogrammetric vectors before and after the impact, impact force, and impact time of the bumper skin under test. The data acquisition device includes at least an accelerometer, a displacement sensor, a trigger sensor, an impact force sensor, and a photogrammetric system.

[0033] The platform is used to hold the bumper skin. See also Figure 4 The platform consists of a lower load-bearing layer 7 and an upper cargo-carrying layer 8.

[0034] The load-bearing layer 7 is made of 10mm thick high-strength steel, with a length of 2150mm and a width of 1000mm. To reduce the platform's weight, the load-bearing layer 7 uses a grid structure with a grid length of 375mm, a width of 350mm, and 8 grids. The cargo layer 8 is used to place counterweights to simulate different weights of the entire vehicle. The cargo layer 8 is made of 5mm thick high-toughness steel, with a length of 2150mm and a width of 1000mm. The cargo-carrying area of ​​the cargo layer 8 (i.e., the groove in the cargo layer) is 1850mm long and 1000mm wide, with the cargo-carrying area 95mm above the ground, and an effective cargo-carrying area of ​​1.665m². 3 It can bear a weight of 1500kg. The load layer 8 is equipped with a gravity sensor, which can set the total weight of the load. If the added weight exceeds the set value, the device will issue an alarm.

[0035] Lifting devices 10 are installed on both sides (protruding parts) of the cargo layer to adjust the height of the cargo layer 8 to simulate different collision heights. This double-layer recessed design can greatly reduce the height of the cargo area, and finally, through the electronic control system, it can achieve precise adjustment within the range of 100mm to 500mm from the ground, meeting the low-speed impact test requirements of all current passenger car bumper skins.

[0036] The load-bearing layer 8 is used to place the bumper skin to be tested. The casters 9 are located at the bottom of the platform to adjust and fix its position. The casters 9 have locking and steering functions, and their direction can be adjusted via an electronic control system (not shown), enabling the platform to move freely and lock, simulating the braking and steering functions of a vehicle.

[0037] In existing technologies, low-speed impact tests on bumper skins typically require a trolley or a complete vehicle, reducing experimental efficiency and increasing costs. Therefore, this method proposes a self-designed mobile lifting platform and skin-bearing fixture. The platform can carry 1500kg, with adjustable height from 100mm to 500mm above the ground, and includes steering, movement, and locking functions. The bumper skin and fixture are placed on the platform for testing, and by adding counterweights, the deformation of the skin is made to match the test conditions of a complete vehicle, efficiently evaluating the product's low-speed impact performance while saving on testing costs. Furthermore, this method uses photogrammetry, skin dent depth, impact force, and impact time as quantitative evaluation methods to compare and analyze the reproduction accuracy of the actual collision process, demonstrating the feasibility of this method. This embodiment allows for the selection of appropriate counterweights based on the material properties of the bumper skin. When the bumper skin is impacted, it will dent. As the total mass of the device increases, the impact force on the skin will also increase, thereby increasing the dent depth. This can simulate different degrees of collision under real vehicle conditions. The load-bearing capacity of 1500kg for the load-bearing layer greatly expands the experimental limits, providing a new verification method for relevant component manufacturers to explore the extreme conditions of the low-speed impact performance of the bumper skin.

[0038] This application also provides a method for evaluating the reproducibility of a low-speed impact test on bumper skin. The low-speed impact test method for bumper skin provided in the above embodiments obtains experimental data under different masses. See also Figure 5 The method for evaluating the replicability of low-speed impact tests on bumper skin includes the following steps: S210. Determine the trend of change in experimental data.

[0039] S220. Compare the described trend with the changes in the bumper skin on the actual vehicle.

[0040] S230. Evaluate the reproduction accuracy of the low-speed impact test on the bumper skin based on the comparison results.

[0041] Optionally, plot the first curve showing the change in scratch width of the bumper skin as a function of mass after a low-speed impact, see [reference]. Figure 6 The characteristics of the first variation curve are compared with the characteristics of the scratch width variation of the bumper skin on the actual vehicle. Figure 6As can be seen, the scratch width (measured with calipers) increases with increasing mass. At a mass of 450kg, the scratch width is 3.82mm, and at a mass of 750kg, it is 7.85mm. This is consistent with the scratch width variation characteristics (e.g., key points, trends, and magnitude) of bumper skin on actual vehicles. Low-speed impacts have relatively small impact energy, generally insufficient to cause bumper breakage, but will leave some scratch marks. This method can effectively assess the degree of damage to the bumper skin.

[0042] Optionally, plot a second curve showing the change in dent depth of the bumper skin as a function of mass after a low-speed impact, see [reference]. Figure 7 The characteristics of the second variation curve are compared with the variation characteristics of the bumper skin indentation depth on a real vehicle. By increasing the counterweight on the platform during low-speed impact, the indentation depth of the bumper skin during an actual vehicle collision is simulated. The distance between the bumper skin and the anti-collision beam (including energy-absorbing blocks) in typical passenger cars and SUVs is 50-100mm. Figure 7 As can be seen, with the increase in mass, the indentation depth of the bumper skin (obtained by the displacement sensor on the impact test bench) increased from 32.2mm to 122.1mm, which is consistent with the indentation depth variation characteristics of the bumper skin on the actual vehicle (such as key nodes, variation trend, and variation magnitude). By increasing the counterweight mass, the low-speed impact condition of the bumper skin can be effectively reproduced.

[0043] Optionally, a photogrammetric vector diagram of the bumper skin before and after a low-speed impact is generated, and the deformation characteristics of the upper body, lower body, and central region of the skin are analyzed. These deformation characteristics are then compared with those of the bumper skin on a real vehicle. Figure 8 This is a photogrammetric vector diagram of the entire post-impact structure provided in the embodiments of this application. Figure 9 This is a photogrammetric vector diagram of the X-direction (perpendicular to the paper and outward) after impact, provided in the embodiments of this application. Figure 8 In this context, dX, dY, and dZ represent the three perpendicular directions, min represents the minimum value, and max represents the maximum value. From... Figure 8 It can be seen that the skin exhibits varying degrees of change in the X, Y, and Z axes. From Figure 9 It can be seen that the upper body of the bumper skin exhibits an inward deformation trend (dX-), while the lower body deforms outward (dX+). This is related to the actual collision conditions. When the hammer impacts the bumper skin, a large indentation area is formed in the center. Within the indentation area, the bumper skin is stretched towards the center. After the indentation area recovers, the surrounding area shows varying degrees of outward expansion. Therefore, the upper body deforms inward, the lower body deforms outward, while the central area only undergoes minor deformation. This phenomenon is consistent with the vehicle collision conditions, thus this method can highly reproduce the deformation of the bumper skin after an actual low-speed collision.

[0044] Optionally, a third curve showing the impact force versus mass during low-speed impacts on the bumper skin can be plotted, and the characteristics of the third curve can be compared with the characteristics of the impact force on the bumper skin on a real vehicle (e.g., key points, trends, and magnitudes of change). Figure 10 As can be seen, the impact force generated by a collision gradually increases with increasing mass. At 750kg, the bumper skin withstands an impact force of 2102.36 N. In actual driving conditions, since the vehicle's mass is much greater than 750kg, the impact force generated in a low-speed collision at a speed not exceeding 4km / h is 5000N~10000N. However, most of the impact energy is absorbed by the EPP (expanded polypropylene) energy-absorbing block behind the bumper skin and the anti-collision beam. Figure 7 It can be seen that when the total mass of the bumper skin system is 750kg during a simulated low-speed collision, the skin indentation depth is 122.1mm. This indentation depth causes the front end of the skin to come into contact with the EPP energy-absorbing block over a large area, and transfers the collision energy.

[0045] Optionally, a fourth curve showing the impact time as a function of mass during a low-speed impact on the bumper skin can be plotted, and the characteristics of this fourth curve can be compared with the characteristics of the impact time variation of the bumper skin on a real vehicle. The impact time (from the contact between the impactor and the bumper skin to the separation process) can be obtained by sensors. Figure 11 As can be seen, the low-speed collision of the bumper skin occurs within 0.16 seconds. As the mass increases, the collision time also gradually increases, but the rate of increase decreases. This is consistent with the characteristics of the collision time of the bumper skin on a real vehicle.

[0046] Optionally, compare whether the inflection points of the fourth variation curve and the second variation curve are consistent. That is, whether the inflection point of the collision time coincides with the inflection point of the indentation depth as the mass increases. Figure 11 and Figure 7 The collision time is related to the dent depth during the collision. Due to the shape limitations of the collider and bumper skin, the dent depth increases with increasing mass (see...). Figure 7 The impact force does not increase linearly, thus reducing the increase in collision time; both inflection points are concentrated around 650 kg. This embodiment can replace a whole vehicle or a trolley to effectively simulate low-speed skin collision performance tests.

[0047] The degree of accuracy is determined based on the level of consistency in the comparison. For example, if all the aforementioned trends of change are consistent with the changes in the bumper skin on the actual vehicle, the score is full marks; if any aspect (such as the trend of change in dent depth or collision time) is inconsistent with the corresponding changes in the actual vehicle, points are deducted appropriately (e.g., 10 points are deducted). If the score is lower than the set value (e.g., 75 points), the experiment is repeated: the mass of the platform is adjusted, and the steps of controlling the collider to impact the bumper skin under test at the set impact speed are returned to obtain experimental data under different masses.

[0048] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this application can be achieved, and this is not limited herein.

[0049] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A low-speed impact test method for bumper skin, characterized in that, include: The bumper skin to be tested is placed on the platform using a tooling. Adjust the position of the platform so that the foremost edge of the bumper skin to be tested is in close contact with the head of the collider; fix the position of the platform; The collider is controlled to collide with the bumper skin under test at a set impact speed; Record experimental data during and after the impact process; The experimental data includes at least: the scratch width, dent depth, pre- and post-collision photogrammetric vectors, impact force, and collision time of the bumper skin under test; Adjust the mass of the platform, return to the step of controlling the collider to collide with the bumper skin under test at a set impact speed, and obtain experimental data under different masses.

2. A low-speed impact testing device for bumper skin, characterized in that, include: Tooling used to secure the bumper skin to be tested; Platform for placing the bumper skin; A collider is used to impact the bumper skin under test at a set impact speed. The data acquisition device is used to record experimental data during and after the impact process. The experimental data includes at least: the scratch width, dent depth, pre- and post-collision photogrammetric vectors, impact force, and collision time of the bumper skin under test; The platform includes a lower load-bearing layer and an upper cargo-carrying layer; The loading layer includes a groove, which is a loading area; The two sides of the loading layer are equipped with lifting devices to adjust the height of the loading layer to simulate different collision heights; The carrier layer is used to place the bumper skin to be tested.

3. The low-speed impact test device for bumper skin according to claim 2, characterized in that, The load layer is used to place counterweights to simulate different weights of the entire vehicle.

4. The low-speed impact test apparatus for bumper skin according to claim 3, characterized in that, It also includes casters located at the bottom of the platform to adjust the position of the platform and fix the platform in place.

5. A method for evaluating the reproducibility of a low-speed impact test on a bumper skin, characterized in that, The low-speed impact test method for bumper skin as described in claim 1 was used to obtain experimental data under different masses; The method for evaluating the replicability of the low-speed impact test on the bumper skin includes: Determine the trend of change in experimental data; The aforementioned trend of change is compared with the change characteristics of the bumper skin on the actual vehicle; The accuracy of the low-speed impact test on the bumper skin was evaluated based on the comparison results.

6. The method for evaluating the reproducibility of low-speed impact tests on bumper skin according to claim 5, characterized in that, The aforementioned trend of change is compared with the changing characteristics of the bumper skin on actual vehicles, including: Plot the first curve of the scratch width of the bumper skin after a low-speed impact as a function of mass, and compare the characteristics of the first curve with the scratch width change characteristics of the bumper skin on a real vehicle. Plot a second curve showing the change in dent depth of the bumper skin as a function of mass after a low-speed impact, and compare the characteristics of the second curve with the characteristics of the change in dent depth of the bumper skin on a real vehicle. Draw photogrammetric vector diagrams of the bumper skin before and after a low-speed impact, and analyze the deformation characteristics of the upper body, lower body and central area of ​​the skin. Compare the deformation characteristics with those of the actual bumper skin on the vehicle. Plot the third curve of impact force versus mass during low-speed impact on the bumper skin, and compare the characteristics of the third curve with the characteristics of impact force variation on the bumper skin on a real vehicle. A fourth curve showing the change in collision time as a function of mass during a low-speed impact on the bumper skin is plotted, and the characteristics of this fourth curve are compared with the characteristics of the change in collision time of the bumper skin on a real vehicle.

7. The method for evaluating the reproducibility of low-speed impact tests on bumper skin according to claim 6, characterized in that, The accuracy of the low-speed impact test on the bumper skin was evaluated based on the comparison results, including: The score of the degree of restoration is determined based on the degree of consistency in the comparison; If the score is lower than the set value, the mass of the platform is adjusted, and the process returns to controlling the collider to collide with the bumper skin under test at the set impact speed, so as to obtain experimental data under different masses.

8. The method for evaluating the reproducibility of low-speed impact tests on bumper skin according to claim 7, characterized in that, The evaluation of the replicability of the low-speed impact test on the bumper skin based on the comparison results also includes: Compare whether the inflection points of the fourth and second change curves are consistent.

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