Simulation test method for stone chip impact on headlights

Abstract

The present invention relates to the technical field of vehicle lamp design, and in particular to a simulation test method for gravel impact of vehicle lamps, comprising the following steps: S1. inputting a digital model of a vehicle lamp into a forward processing software, and performing grid division; S2. inputting material information and boundary condition information into the forward processing software; S3. importing the files obtained in S1 and S2 into a finite element analysis software, inputting simulation test conditions, and obtaining a maximum stress value; S4. comparing the maximum stress value with the yield strength of the material, if the maximum stress value is less than the yield strength of the material, judging that a vehicle lamp cover has no plastic deformation and cracking risk according to the simulation, and making the vehicle lamp into a physical product to conduct gravel impact equipment verification to obtain a verification result; if the maximum stress value is greater than the yield strength of the material, judging that a vehicle lamp cover has plastic deformation and cracking risk according to the simulation, optimizing the vehicle lamp structure to obtain an improved digital model of the vehicle lamp, and returning to S1 until the simulation result judges that the vehicle lamp cover has no plastic deformation and cracking risk.

Description

Technical Field

[0001] The invention relates to the technical field of vehicle lamp design, in particular to a simulation test method for stone chip impact on vehicle lamps. Background Art

[0002] When a car is driving, the driving environment is difficult to predict. Sometimes it passes through mountainous areas with frequent gravel, and sometimes gravel falls from the other party's stone transport truck, which may impact the headlight mask. If the mask is not strong enough after the impact, it will cause it to break, which will cause water to enter the headlight and fog, affecting the lighting and causing the entire lamp to be scrapped. In order to avoid economic losses caused by gravel impact on the headlight, a gravel impact test is required during the development stage of the headlight to verify whether the headlight mask meets the strength requirements.

[0003] In the process of designing headlights, engineers design the headlight mask structure based on experience, which often results in insufficient strength or "over-design". In the test phase, they only use gravel tossing or free-falling objects to hit the headlights, which makes it difficult to control the speed of the gravel impact and reproduce the actual working conditions. The national standard GB / T 10485-2007 "Environmental resistance of road vehicle external lighting and light signal devices" also provides a light distribution mirror strength test method, which only uses a simple physical test method to judge the gravel impact resistance of the headlight. On the one hand, the reliability is low, and on the other hand, the efficiency of physical testing is low. If the actual product does not meet the standard, it will undergo repeated modifications, resulting in a longer product development cycle and increased development costs. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a simulation test method for stone chip impact of a headlight, comprising the following steps:

[0005] S1. Input the digital model of the headlight into the forward processing software and perform mesh division;

[0006] S2. Input material information and boundary condition information into the forward processing software;

[0007] S3. Import the files obtained in S1 and S2 into the finite element analysis software, input the simulation test conditions, and obtain the maximum stress value;

[0008] S4. Compare the maximum stress value with the yield strength of the material. If the maximum stress value is less than the yield strength of the material, the simulation determines that the headlight mask has no risk of plastic deformation and rupture, and the headlight is made into a physical product and subjected to gravel impact equipment verification to obtain a verification result. If the maximum stress value is greater than the yield strength of the material, the simulation determines that the headlight mask has risk of plastic deformation and rupture, and the digital model of the headlight after the optimization of the headlight structure is improved, and returns to S1 until the simulation result determines that the headlight mask has no risk of plastic deformation and rupture.

[0009] As a preferred technical solution, the method further includes step S5: optimizing the material information and boundary condition information in S2 and the simulation test conditions in S3 according to the verification result of the stone crushing impact equipment.

[0010] As a preferred technical solution, the grid size of the grid division is 0.5-5 mm.

[0011] As a preferred technical solution, the mesh type of the mesh division is a mixed unit of triangles and quadrilaterals.

[0012] As a preferred technical solution, the material information includes the mask material and the lamp body material; the boundary condition information includes the connection method between the mask and the lamp body, and the installation method of the lamp body.

[0013] As a preferred technical solution, the simulation test conditions include gravel conditions.

[0014] As a preferred technical solution, the gravel conditions at least include gravel shape, gravel size, gravel material, and gravel initial velocity.

[0015] As a preferred technical solution, the gravel impact equipment includes a gravel storage area; the gravel storage area is connected to a gravel channel below through an inclined surface; one end of the gravel channel is connected to an air duct; the air duct is connected to a pressure control valve and a pressure display gauge in sequence; the other end of the gravel channel is arranged opposite to a gravel window; the gravel window is connected to a headlight mounting bracket, and during the test, the headlight is fixed on the headlight mounting bracket, and gravel passes through the gravel window and impacts the headlight; a gravel recovery area is arranged below the gravel window and the headlight mounting bracket.

[0016] As a preferred technical solution, the gravel window is composed of a gravel window upper support and a gravel window lower support; the gravel window upper support and the gravel window lower support are fixed in the device in the form of slide rails.

[0017] As a preferred technical solution, the gravel window is connected to the headlight fixing frame by means of screws.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. In the early stage of lamp research and development, perform gravel collision simulation on the lamp, extract the stress distribution cloud map results of the mask, compare the yield strength of the material, and determine whether the mask has the risk of plastic deformation and rupture, so as to avoid the waste of time and manpower costs caused by invalid physical testing;

[0020] 2. In the early stage of lamp development, simulation can be used to quickly compare multiple solutions, effectively avoid potential risks, and avoid multiple mold modifications in the later stage of physical verification, which generally shortens the product development cycle and reduces development costs;

[0021] 3. Use reasonably designed gravel impact equipment to make the equipment more applicable and convenient for testing the lights of different projects and under different test conditions;

[0022] 4. The finite element simulation method is combined with actual test analysis. The actual test results can provide data support for the simulation and continuously correct the simulation model to get closer to the actual working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to further explain the beneficial effects of the simulation test method for the stone chip impact of headlights provided in the present invention, corresponding drawings are provided. It should be pointed out that the drawings provided in the present invention are only individual examples selected from all the drawings, and are not intended to be a limitation on the claims. All other corresponding graphs obtained through the drawings provided in this application should be considered to be within the scope of protection of this application.

[0024] Figure 1 The figure is a flow chart of the simulation test method for the impact of gravel on vehicle headlights in the present invention.

[0025] Figure 2 FIG. 4 is a stress distribution diagram of a headlight cover obtained through simulation in an embodiment of the present invention.

[0026] Figure 3 It is a schematic diagram of the structure of the stone crushing impact device in an embodiment of the present invention.

[0027] Figure numerals: 1-pressure display gauge, 2-pressure control valve, 3-air duct, 4-gravel storage area, 5-gravel channel, 6-gravel window upper support, 7-gravel window lower support, 8-headlight fixing bracket, 9-headlight, 10-gravel recovery area. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0030] In this document, relational terms such as first, second, third, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises", or any other variations thereof are intended to cover non-exclusive inclusion, so that a component, device, or equipment that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such component, device, or equipment.

[0031] The meaning of "and / or" in the present invention means that both situations where each exists alone or both exist at the same time are included.

[0032] The meaning of "inside" and "outside" in the present invention refers to the direction pointing to the inside of the device as inside, and the opposite direction as outside, relative to the device itself, rather than being a specific limitation on the device mechanism of the present invention.

[0033] The meaning of "left and right" in the present invention refers to that when the reader is facing the accompanying drawings, the left side of the reader is left and the right side of the reader is right, rather than a specific limitation on the device mechanism of the present invention.

[0034] The meaning of “upper and lower” in the present invention refers to that when a reader is facing the accompanying drawings, the upper side of the reader is the upper side and the lower side of the reader is the lower side, rather than being a specific limitation on the device mechanism of the present invention.

[0035] The term “connection” as used in the present invention may mean a direct connection between components or an indirect connection between components via other components.

[0036] In order to solve the above problems, the present invention provides a simulation test method for the impact of gravel on a headlight, such as Figure 1 As shown, the following steps are included:

[0037] S1. Input the digital model of the headlight into the forward processing software and perform mesh division;

[0038] S2. Input material information and boundary condition information into the forward processing software;

[0039] S3. Import the files obtained in S1 and S2 into the finite element analysis software, input the simulation test conditions, and obtain the maximum stress value;

[0040] S4. Compare the maximum stress value with the yield strength of the material. If the maximum stress value is less than the yield strength of the material, the simulation determines that the headlight mask has no risk of plastic deformation and rupture, and the headlight is made into a physical product and subjected to gravel impact equipment verification to obtain a verification result. If the maximum stress value is greater than the yield strength of the material, the simulation determines that the headlight mask has risk of plastic deformation and rupture, and the digital model of the headlight after the optimization of the headlight structure is improved, and returns to S1 until the simulation result determines that the headlight mask has no risk of plastic deformation and rupture.

[0041] The pre-processing software in the present invention refers to finite element pre-processing software, which is used for operations such as geometry processing, material setting, meshing, and boundary application. There is no special restriction on its specific selection, and examples include ANSA, Hypermesh, and Patran.

[0042] The digital model of the vehicle lamp in the present invention, that is, the mathematical modeling of the vehicle lamp design, can be a vehicle lamp design drawing designed and manufactured using any three-dimensional modeling software.

[0043] In some preferred embodiments, the grid size of the grid division is 0.5-5 mm; further preferably, the grid size of the grid division is 1-4 mm.

[0044] In some preferred embodiments, the mesh type of the mesh division is a mixed unit of triangles and quadrilaterals.

[0045] The material of the headlight is related to its resistance to gravel impact. At the same time, the connection method of the headlight components and the connection method of the headlight and the body sheet metal will also affect the headlight's resistance to gravel impact. In some preferred embodiments, the material information includes the mask material and the lamp body material; the boundary condition information includes the connection method between the mask and the lamp body, and the installation method of the lamp body.

[0046] In the field of automotive lamps, the material of automotive lamp masks can usually be PC (polycarbonate); the material of lamp bodies can usually be PP-TD30 (polypropylene containing 30wt% talc filler), PP-TD40 (polypropylene containing 40wt% talc filler), PP-TD20 (polypropylene containing 20wt% talc filler), etc.; the connection method between the mask and the lamp body can usually be welding; the installation method of the lamp body can usually be installed by mounting feet.

[0047] In steps S1 and S2, the pre-processing software meshes the digital model of the headlights, and performs pre-processing work such as material setting, material assignment, and boundary condition setting in the software. The processed files can be further solved using finite element analysis software.

[0048] The finite element analysis software in the present invention is not particularly limited, and may be any one known to those skilled in the art, such as ANSYS_LS-DYNA, LUSAS, MSC.Nastran, Abaqus, Femap / NX Nastran, and the like.

[0049] In step S3, by simulating gravel impact, the stress distribution diagram of the headlight mask is obtained, and then the maximum stress value of the mask after being impacted by gravel is obtained. In order to obtain test results closer to the actual ones, in some preferred embodiments, the simulation test conditions include gravel conditions; further preferably, the gravel conditions at least include gravel shape, gravel size, gravel material, and gravel initial velocity; further, the gravel is a sphere with a diameter of 4 to 15 mm, the material is a rigid body that does not deform, and the initial velocity is 5 to 20 m / s. Before solving, the gravel should also be pre-processed and imported into the finite element analysis software.

[0050] In step S4, by comparing the maximum stress value with the yield strength of the material, it is determined whether the headlight cover has the risk of plastic deformation and cracking. If there is no risk, the actual product can be verified by the gravel impact equipment to shorten the product development cycle, avoid unnecessary physical verification, and reduce development costs.

[0051] In some preferred embodiments, the gravel impact device includes a gravel storage area; the gravel storage area is connected to a gravel channel below via an inclined surface; one end of the gravel channel is connected to an air duct; the air duct is connected to a pressure control valve and a pressure display gauge in sequence; the other end of the gravel channel is arranged opposite to a gravel window; the gravel window is connected to a headlight mounting bracket, and during the test, the headlight is fixed on the headlight mounting bracket, and gravel passes through the gravel window and impacts the headlight; a gravel recovery area is arranged below the gravel window and the headlight mounting bracket.

[0052] In some preferred embodiments, the stone crushing window is composed of a stone crushing window upper support and a stone crushing window lower support; the stone crushing window upper support and the stone crushing window lower support are fixed in the device in the form of a slide rail. The stone crushing window in the present invention can move left and right on the slide rail to adjust the distance between the stone crushing window and the stone crushing channel outlet, that is, to adjust the distance of stone crushing impact.

[0053] In some preferred embodiments, the gravel window is connected to the headlight fixing frame by means of screws, which is convenient for disassembly and replacement, and is conducive to testing of headlights for different projects.

[0054] In order to make the test closer to the actual scene, in some preferred embodiments, the crushed stone used in the crushed stone impact device is made of cast iron HRC57-62, has an angular shape, and has an average diameter of 4 to 10 mm.

[0055] The stone crushing impact device of the present invention uses air pressure to impact stone crushing, which can effectively control the speed of stone crushing, and can perform impact tests under different speed requirements. In some preferred embodiments, the compressed air pressure that can be controlled by the stone crushing impact device is 0.5-2 Bar, and the stone crushing impact speed that can be provided is 8-15 m / s.

[0056] When the above-mentioned gravel impact equipment is in use, the gravel is placed in the gravel storage area, and the pressure control valve is opened at the same time. The gravel slides along the slope to the gravel channel. Under the impact of strong airflow, the gravel passes through the gravel window to reach the surface of the headlight mask. After all the gravel impact is completed, the headlight is removed and the cracks and damages of the headlight mask are observed.

[0057] In some preferred embodiments, the method for simulating the gravel impact of a headlight further comprises step S5: optimizing the material information and boundary condition information in S2 and the simulation test conditions in S3 according to the verification result of the gravel impact equipment.

[0058] According to the verification results of the gravel impact equipment, the settings in the visiting team's simulation test are adjusted. On the one hand, the test process can be compared. According to the working conditions of the equipment for gravel impact, such as impact direction, angle, speed or gravel material, the simulation conditions are adjusted to make the conditions of the actual test consistent with those of the simulation test; on the other hand, the test results can be compared. If the simulation results do not match the equipment test results, it means that there is a deviation between the simulation conditions and the actual objects, and optimization is needed.

[0059] The present invention provides a simulation test method for gravel impact of headlights. In the early stage of headlight research and development, a gravel impact simulation analysis is performed on a digital model of the headlight to determine whether there is a risk of plastic deformation and cracking of the headlight mask. After the simulation is risk-free, equipment verification is performed, thereby avoiding multiple mold modifications in the later physical verification stage. Overall, the product development cycle is shortened and the development cost is reduced. The reasonable design of the gravel impact equipment extends the application range of the equipment, making it convenient to perform tests on headlights of different projects and under different test conditions.

[0060] Example

[0061] The present invention is described in detail below by way of examples. It is necessary to point out here that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by professionals and technicians in this field based on the content of the present invention above still belong to the scope of protection of the present invention.

[0062] This embodiment provides a method for simulating a headlight stone impact test, comprising the following steps:

[0063] a. Import the digital model of the headlight into the ANSA software for meshing, set the mesh size to 2mm, and the mesh type to a mixed unit of triangles and quadrilaterals;

[0064] b. Set the lamp mask material to PC (polycarbonate), the lamp body material to PP-TD30 (polypropylene containing 30wt% talc filler), the mask and the lamp body are welded, and the mounting feet of the lamp body are set as constraints according to the loading state;

[0065] c. Export the data in step b and import it into ANAYS_LS-DYNA software, set the simulation test conditions, select the gravel as a sphere with a diameter of 8mm (already meshed), the material is a rigid body without deformation, and set the initial velocity of the sphere to 10m / s;

[0066] d. According to the simulation test conditions of step c, extract the simulation results, that is, the stress distribution diagram of the headlight mask, such as Figure 2 As shown, the results show that the maximum stress value is 18MPa, which is less than the yield strength of the material 65MPa, indicating that no plastic deformation occurs and there is no risk of rupture;

[0067] e. The actual product is made according to the digital model of the headlight and verified using a gravel impact device to ensure the safety of the headlight under gravel impact conditions.

[0068] The stone crushing impact device, such as Figure 3 As shown, it includes a gravel storage area 4; the gravel storage area 4 is connected to the gravel channel 5 below through an inclined surface, so that the gravel in the gravel storage area 4 can fall into the gravel channel 5 through the inclined surface; one end of the gravel channel 5 is connected to the air guide pipe 3, so that the gravel falling into the gravel channel 5 flies out of the gravel channel 5 under the action of air pressure; the air guide pipe 3 is connected to the pressure control valve 2, and the pressure control valve 2 can control the air pressure of the air guide pipe 3; the pressure control valve 2 is connected to the pressure display meter 1, and the air pressure can be obtained by reading the pressure display meter 1; the other end of the gravel channel 5 is arranged opposite to the gravel window, so that the gravel flying out of the gravel channel 5 The stone enters the gravel window; the gravel window is composed of an upper support 6 for the gravel window and a lower support 7 for the gravel window; the upper support 6 for the gravel window and the lower support 7 for the gravel window are fixed in the device in the form of slide rails and can be moved left and right to adjust the distance between the gravel window and the exit of the gravel channel 5; the gravel window is connected to the headlight fixing frame 8 by screws, and the headlight 9 is fixed on the headlight fixing frame 8 during the test. As the gravel window moves, the distance between the headlight 9 and the exit of the gravel channel 5 changes; a gravel recovery area 10 is arranged below the gravel window and the headlight fixing frame 8 to facilitate the recovery and reuse of gravel.

[0069] When the above-mentioned gravel impact equipment is in use, 500 mL of gravel is placed in the gravel storage area 4, and the pressure control valve 2 is opened at the same time. The gravel slides along the slope to the gravel channel 5. Under the impact of strong airflow, the gravel passes through the gravel window and reaches the mask surface of the headlight 9. After all the gravel has been impacted, the headlight 9 is removed and the cracking and damage of the headlight mask is observed.

[0070] The foregoing examples are merely illustrative and are used to explain some features of the method of the present invention. The appended claims are intended to claim the widest possible range that can be conceived, and the embodiments presented herein are only illustrations of selected implementations according to the combination of all possible embodiments. Therefore, it is the applicant's intention that the appended claims are not limited by the selection of examples that illustrate the features of the present invention. Some numerical ranges used in the claims also include sub-ranges within them, and changes in these ranges should also be interpreted as being covered by the appended claims where possible.

Claims

1. A simulation test method for the impact of gravel on a headlight, characterized in that: The following steps are involved: S1. Input the digital model of the headlight into the forward processing software and perform mesh division; S2. Input material information and boundary condition information into the forward processing software; S3. Import the files obtained in S1 and S2 into the finite element analysis software, input the simulation test conditions, and obtain the maximum stress value; S4. Compare the maximum stress value with the yield strength of the material. If the maximum stress value is less than the yield strength of the material, the headlight mask is judged to have no risk of plastic deformation and rupture based on the simulation. The headlight is made into a physical product and tested with a gravel impact device to obtain the verification result. If the maximum stress value is greater than the yield strength of the material, the headlight cover is judged to have plastic deformation and rupture risks according to the simulation, and the headlight digital model after the headlight structure optimization is improved is returned to S1 until the simulation results judge that the headlight cover has no plastic deformation and rupture risks; S5: Optimize the material information, boundary condition information in S2 and the simulation test conditions in S3 according to the verification results of the stone impact equipment; The mesh size of the mesh division is 0.5 to 5 mm; The gravel impact equipment includes a gravel storage area; the gravel storage area is connected to a gravel channel below through an inclined surface; one end of the gravel channel is connected to an air duct; the air duct is connected to a pressure control valve and a pressure display gauge in sequence; the other end of the gravel channel is arranged opposite to a gravel window; the gravel window is connected to a headlight mounting bracket, and during the test, the headlight is fixed on the headlight mounting bracket, and gravel passes through the gravel window and impacts the headlight; a gravel recovery area is arranged below the gravel window and the headlight mounting bracket.

2. The method for simulating the impact of gravel on a headlight as claimed in claim 1, characterized in that: The mesh type of the mesh division is a mixed unit of triangles and quadrilaterals.

3. The method for simulating the impact of gravel on a headlight as claimed in claim 1, characterized in that: The material information includes the mask material and the lamp body material; the boundary condition information includes the connection method between the mask and the lamp body, and the installation method of the lamp body.

4. The method for simulating the stone chip impact of a headlight according to claim 1, characterized in that: The simulated test conditions include gravel conditions.

5. The method for simulating the stone chip impact of a headlight according to claim 4, characterized in that: The gravel conditions at least include gravel shape, gravel size, gravel material, and gravel initial velocity.

6. The method for simulating the impact of gravel on a headlight as claimed in claim 1, characterized in that: The gravel window is composed of a gravel window upper support and a gravel window lower support; the gravel window upper support and the gravel window lower support are fixed in the equipment in the form of slide rails.

7. The method for simulating the stone chip impact of a headlight according to claim 1, characterized in that: The gravel window is connected to the vehicle light fixing frame by means of screws.

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