A simulation method, device and storage medium for pedestrian protection crushable wiper shaft

Abstract

The application discloses a kind of simulation modeling method, equipment and storage medium for pedestrian protection crushable wiper shaft, belong to simulation technical field, including model structure simplification, mesh division, material definition and relative motion constraint, the establishment of simulation model;The application uses spring instead of gasket to simulate crushing, and obtains the relationship curve of crushing force and displacement through the crushable wiper shaft sub-test system for the definition of spring material curve of simulation model, which can solve the problem that gasket crushing process is not easy to simulate and control, improve the calculation efficiency, and provide an adjustable parameter for simulation calibration;Define the key component material as rigid material, establish the relative motion relationship instead of traditional rigid connection, accurately simulate the crushing distance, improve the simulation accuracy of head injury in wiper area for pedestrian protection, more accurately provide the simulation prediction injury value in wiper area, avoid the disadvantages of relying on the whole vehicle head shape test method, and be beneficial to the positive guidance of wiper crush force design and optimization in research and development stage.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of simulation, and particularly relates to a simulation method and device for a crushable wiper shaft for pedestrian protection and a storage medium. BACKGROUND

[0002] With the improvement of social and economic level and the progress of science and technology, automobiles have become an important tool for people to travel. The increase of automobiles inevitably leads to the increase of traffic accidents, and pedestrians as the vulnerable group on the road usually suffer serious injuries in traffic accidents, of which the mortality rate of head injuries is relatively high. The protection of pedestrians in automobile collisions has been paid more and more attention by more and more countries, and has been gradually incorporated into the evaluation of automobile safety regulations since the 1980s. In 2018, China officially incorporated pedestrian protection into the new car evaluation system C-NCAP, and in 2021, the landing point of the head impact of two-wheeled vehicle riders was considered, the head injury range was expanded from WAD2100 (the surface envelope distance of the automobile) to WAD2300, and the evaluation was expanded from the traditional engine cover area to the front wiper and windshield area. With the upgrading of regulations, the evaluation range will continue to expand year by year. The pedestrian protection performance of a vehicle directly affects the safety star of the vehicle, affects the life safety of pedestrians, and becomes an important link in the future development of China's automobile safety. China's automobile pedestrian protection started late, and at present, many vehicles on the market do not consider pedestrian protection, and the related protection measures and methods are not perfect and need to be improved.

[0003] The pedestrian protection verification test has the characteristics that the simulation injury prediction participates in the final score. Since there are many evaluation points for pedestrian head protection, every 100mm multiplied by 100mm has an evaluation point, and there are about 200 points in the current evaluation range. Considering the cost and period, it is impossible to test each evaluation point. When the final test evaluation is performed, the predicted injury of 200 points is provided in advance, and then a number of points (about 10 points) are randomly selected for testing, compared with the prediction of the point, the correction coefficient is calculated (required to be within a reasonable range, otherwise treated according to the worst coefficient), and the final score is calculated relying on the prediction value of the 200 head evaluation points and the correction coefficient. The final comprehensive score is calculated based on the injury prediction and correction coefficient provided in advance; the injury prediction participates in the final score calculation of the pedestrian head protection, and the injury prediction mainly depends on simulation, so in the development of automobile products, high requirements are put forward for the simulation accuracy of each evaluation point of the pedestrian head protection.

[0004] With the expansion of the evaluation range of pedestrian protection regulations, the front windshield wiper area becomes an important part of the evaluation of head injury of automobile pedestrians. The structure of the automobile front wiper is complex, and the current mainstream method is to process the wiper system as a whole rigidity, only considering its occupation characteristics. In order to reduce the head injury to pedestrians and improve the head score of pedestrian protection, more and more OEMs use crush wipers. In order to reduce the head injury to pedestrians, the current mainstream equipment of various OEMs is a crush wiper shaft, but there is a lack of a more perfect high-precision simulation modeling method, and the score prediction of this area relies on the whole vehicle head impact test, which has high test cost, poor stability, and is not conducive to rectification after problems are found, and has the disadvantage of being unable to positively guide the design to optimize the crush force of the wiper shaft. But the application of the original whole rigidity processing cannot consider the actual crush process, the simulation precision is low, the head injury value simulated is high, and it does not have the condition of high-precision prediction. SUMMARY

[0005] In order to solve the problems of inaccurate simulation prediction of the pedestrian protection head wiper area and relying on the whole vehicle head test in the prior art, the present application provides a simulation modeling method, equipment and storage medium for a pedestrian protection crush wiper shaft, which uses a spring instead of a gasket to simulate crushing, solves the problem that the gasket crushing process is not easy to simulate and control, improves the calculation efficiency, and provides an adjustable parameter for simulation calibration; the simulation precision of the head injury of the wiper area of the pedestrian protection can be improved, the simulation prediction injury value of the wiper area can be more accurately provided, the disadvantages of relying on the whole vehicle head test method are avoided, and it is beneficial to positively guide the design and optimization of the wiper crush force in the research and development stage.

[0006] The present application is realized by the following technical solutions:

[0007] A simulation modeling method for a pedestrian protection crush wiper shaft, specifically comprising the following steps:

[0008] Step S1: model structure simplification:

[0009] A spring unit is used instead of a gasket modeling;

[0010] Step S2: meshing:

[0011] Establish a finite element simulation model of the crush component;

[0012] Step S3: material definition and relative motion constraint:

[0013] The material definition includes that the spring material parameters are defined by a spring stiffness curve, and the spring stiffness curve is obtained through a crush wiper shaft test system; the swing arm support, swing shaft and support are defined as rigid materials;

[0014] The relative motion constraint includes establishing nodes at the centers of the swing arm support limiting surface and the bracket limiting surface, respectively, and establishing a cylindrical movement pair between the two nodes to define the coaxial relative sliding relationship between the swing shaft and the bracket, and a rigid connection is used to simulate the threaded connection;

[0015] Step S4: Establishment of simulation model:

[0016] The contact relationship between the swing shaft and the bracket is defined separately, and the establishment of a high-precision simulation model is realized based on the adjustment of the parameter static friction coefficient (FS) and dynamic friction coefficient (FD).

[0017] Further, in step S1, the DISCRETE spring element in LS_DYNA software is used to simulate the crushing and falling process instead of the gasket, the DISCRETE ELEMENT TYPE is set to Displacement, and the MAT_S08 SPRING_INELASTIC material card is used to define the spring parameters. The parameter LCFD force-displacement curve needs to be calibrated in the material card.

[0018] Further, the finite element simulation model of the crushing component in step S2 includes a rubber cap simulation model 10, a swing arm support simulation model 20, a swing shaft simulation model 30, a bracket model 40, a connecting rod model 70, a cylindrical movement pair simulation model 100, and a spring simulation model 101.

[0019] Further, step S2 is specifically as follows:

[0020] The wiper shaft and the swing arm support are modeled as an outer shell, with the surface location defined as the top surface and the thickness defined as 1mm. The bracket is modeled as an extracted surface, with the surface location defined as the center surface and the thickness defined as twice the distance from the bracket surface to the outer surface of the wiper shaft. The material is defined as MAT_020 RIGID. The remaining structures are defined according to the actual material and thickness, with a grid base size of 2mm.

[0021] Further, step S3 includes the following steps:

[0022] Step S31: Build a crushing wiper shaft sub-test system;

[0023] Step S32: Simulate the constant speed loading perpendicular to the swing shaft direction for the crushing test;

[0024] Step S33: Extract the pressure F-time t curve of the wiper shaft crushing process, and integrate the loading speed displacement S-time t relationship to obtain the pressure F-displacement S curve;

[0025] Step S34: repeat step S33 multiple times, remove abnormal curves, and average other curves. The processed curve is defined as the spring stiffness curve in the simulation model.

[0026] Step S35: rigidly process the swing arm support, wiper shaft, and bracket in the simulation model, and define the material as MAT_020RIGID. Other structures are defined according to actual materials.

[0027] Step S36: define the relative motion relationship between the wiper shaft and the bracket using JOINT_Cylindrical. The swing arm support 2 and the swing shaft 3 are threadedly connected using RIGID_BODIES for rigid locking. The swing shaft 3 and the connecting rod 7 are threadedly connected using EXTRA_NODES for rigid-flexible connection.

[0028] Further, the step S31 of building the crush-type wiper shaft sub-test system is as follows: prepare the crush wiper shaft assembly, remove the connecting rod 7 and the rubber cap 1, and retain the remaining structures, including the swing arm support 2, the swing shaft 3, the bracket 4, the crush gasket 5, and the shaft sleeve 6. The two ends of the bracket 4 are fixed by a bracket fixing clamp, and a loading device is arranged above the swing arm support 2. The loading device includes a loading disc 1000 and a pressure sensor 1001 located on the loading disc 1000.

[0029] Further, the specific steps of step S3 are as follows: build a crush-type wiper shaft sub-test system; fix the bracket by a bracket fixing clamp; load the loading disc at a constant speed of 1mm / s perpendicular to the swing shaft; the gasket 5 is crushed and broken, and then the swing shaft 3 and the swing arm support 2 slide along the axis direction of the bracket 4. The crush distance is determined by the distance between the lower end surface of the swing arm support 2 and the upper end surface of the bracket 4. The loading distance is the actual measured crush distance. The pressure F-time t curve of the wiper shaft crush process is extracted by the pressure sensor on the loading disc. The pressure F-displacement S curve is obtained by combining the loading speed displacement S-time t relationship. Repeat the test more than 6 times, remove the abnormal curves, and average the other curves. The processed curve is defined as the material curve of the spring in the simulation model.

[0030] Further, the step S4 is as follows:

[0031] The assembly is self-contacted, the LS_DYNA control card is *AUTOMATIC_SINGLE_SURFACE, the contact between the swing shaft and the support is established separately, and the control card is *AUTOMATIC_SURFACE_TO_SURFACE; the simulation calibration of the crushing process is realized by adjusting the static friction coefficient (FS) and the dynamic friction coefficient (FD) between the swing shaft and the support, until the fitting degree of the force-displacement curve output by the simulation spring and the crushing force-displacement curve of the test is more than 90%, and the simulation model is established.

[0032] In a second aspect, the embodiments of the present application further provide a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the simulation modeling method for the pedestrian protection crushable wiper shaft according to any one of the embodiments of the present application when executing the program.

[0033] In a third aspect, the embodiments of the present application further provide a computer readable storage medium, which stores a computer program, and the program is executable on a processor to implement the simulation modeling method for the pedestrian protection crushable wiper shaft according to any one of the embodiments of the present application.

[0034] Compared with the prior art, the present application has the following advantages:

[0035] (1) The simulation model is simple in structure, simplifies the actual complex structure, uses a spring element to replace a gasket to simulate crushing, solves the problem that the gasket crushing process is not easy to simulate and control, improves the calculation efficiency, and provides an adjustable parameter for simulation calibration;

[0036] (2) The rigid support, rigid swing shaft and rigid swing arm support are used to avoid abnormal flexible deformation caused by grid quality, accurately define the crushing stroke, and further improve the simulation accuracy;

[0037] (3) The relative motion relationship between the swing shaft and the support is defined by JOINT flexibility, which replaces the traditional rigid connection lock to solve the problem of large simulation value and inaccurate accuracy, and is closer to the actual working condition;

[0038] (4) The relationship curve between the crushing force and the displacement obtained by designing the crushing wiper shaft subsystem test is used to define the spring material curve of the simulation model, and the simulation accuracy is improved;

[0039] (5) The surface-to-surface contact between the swing shaft and the support is defined separately, the dynamic and static friction coefficients are adjusted, the simulation model is calibrated, and the simulation accuracy is more than 90%;

[0040] (6), the simulation model of the crushable wiper shaft for pedestrian protection based on the method can be used for precise prediction of head injury in the wiper area in the research and development stage, and positively guide the design of the crush force of the wiper shaft. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0042] Figure 1 A simulation method flow chart for the crushable wiper shaft for pedestrian protection is provided for the embodiments of the present application;

[0043] Figure 2 A crushable wiper shaft assembly structure schematic diagram is provided for the embodiments of the present application;

[0044] Figure 3 A simulation model schematic diagram for the crushable wiper shaft for pedestrian protection is provided for the embodiments of the present application;

[0045] Figure 4 A crushable wiper shaft sliding pair and spring simulation model schematic diagram is provided for the embodiments of the present application;

[0046] Figure 5 A test schematic diagram of the crushable wiper shaft sub-test system is provided for the embodiments of the present application;

[0047] Figure 6 A crush force F-displacement S curve diagram is provided for the embodiments of the present application;

[0048] Figure 7 A flowchart of step S3 of the present application is provided;

[0049] Figure 8 A structure schematic diagram of an electronic device in embodiment 3 of the present application is provided.

[0050] The reference numerals are explained as follows:

[0051] 1 is a rubber cap, 2 is a swing arm support, 3 is a swing shaft, 4 is a support, 5 is a gasket, 6 is a shaft sleeve, 7 is a connecting rod, 10 is a rubber cap simulation model, 20 is a swing arm support simulation model, 30 is a swing shaft simulation model, 40 is a support model, 70 is a connecting rod simulation model, 100 is a cylindrical moving pair simulation model, 101 is a spring simulation model, 201 is the center of the swing arm support crushing limit surface, 401 is the center of the support crushing limit surface, 1000 is a loading disc, 1001 is a pressure sensor, 1002 and 1003 are support fixing clamps. DETAILED DESCRIPTION

[0052] In order to clearly and completely describe the technical solutions of the present application and the specific working process thereof, the specific embodiments of the present application are as follows in combination with the accompanying drawings of the specification:

[0053] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, the skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0054] A simulation modeling method for a pedestrian protection crushing wiper shaft, specifically comprising the following steps:

[0055] Step S1: model structure simplification:

[0056] The spring unit is used to replace the gasket modeling;

[0057] Step S2: meshing:

[0058] Establish a finite element simulation model of the crushing component;

[0059] Step S3: material definition and relative motion constraint:

[0060] The material definition includes the definition of the spring material parameters obtained from the spring stiffness curve, and the spring stiffness curve is obtained through the crushing wiper shaft sub-test system; the swing arm support, the swing shaft and the support are defined as rigid materials;

[0061] The relative motion constraint includes establishing nodes at the centers of the swing arm support limiting surface and the bracket limiting surface, respectively, and establishing a cylindrical movement pair between the two nodes to define the coaxial relative sliding relationship between the swing shaft and the bracket, and a rigid connection is used to simulate the threaded connection;

[0062] Step S4: Establishment of simulation model:

[0063] The contact relationship between the swing shaft and the bracket is defined separately, and the establishment of a high-precision simulation model is realized based on the adjustment of the parameter static friction coefficient (FS) and dynamic friction coefficient (FD).

[0064] Further, in step S1, the DISCRETE spring element in LS_DYNA software is used to simulate the crushing and falling process instead of the gasket, the DISCRETE ELEMENT TYPE is set to Displacement, and the MAT_S08 SPRING_INELASTIC material card is used to define the spring parameters. The parameter LCFD force-displacement curve needs to be calibrated in the material card.

[0065] Further, the finite element simulation model of the crushing component in step S2 includes a rubber cap simulation model 10, a swing arm support simulation model 20, a swing shaft simulation model 30, a bracket model 40, a connecting rod model 70, a cylindrical movement pair simulation model 100, and a spring simulation model 101.

[0066] Further, the step S2 is specifically as follows:

[0067] The wiper shaft and the swing arm support are modeled as an outer shell, with the surface location defined as the top surface and the thickness defined as 1mm. The bracket is modeled as an extracted surface, with the surface location defined as the center surface and the thickness defined as twice the distance from the bracket surface to the outer surface of the wiper shaft. The material is defined as MAT_020 RIGID. The remaining structures are defined according to the actual material and thickness, with a grid base size of 2mm.

[0068] Further, the step S3 includes the following steps:

[0069] Step S31: Building a crushing wiper shaft sub-test system;

[0070] Step S32: Simulating the constant speed loading perpendicular to the swing shaft for the crushing test;

[0071] Step S33: Extracting the pressure F-time t curve of the wiper shaft crushing process, and converting the pressure F-displacement S curve by comprehensively considering the loading speed displacement S-time t relationship;

[0072] Step S34: repeat step S33 multiple times, remove abnormal curves, and average other curves. The processed curve is defined as the spring stiffness curve in the simulation model.

[0073] Step S35: rigidly process the swing arm support, wiper shaft, and bracket in the simulation model, and define the material as MAT_020RIGID. Other structures are defined according to actual materials.

[0074] Step S36: define the relative motion relationship between the wiper shaft and the bracket using JOINT_Cylindrical. The swing arm support 2 and the swing shaft 3 are threadedly connected using RIGID_BODIES for rigid locking. The swing shaft 3 and the connecting rod 7 are threadedly connected using EXTRA_NODES for rigid-flexible connection.

[0075] Further, the step S31 of building the crush-type wiper shaft sub-test system is as follows: prepare the crush wiper shaft assembly, remove the connecting rod 7 and the rubber cap 1, and retain the remaining structures, including the swing arm support 2, the swing shaft 3, the bracket 4, the crush gasket 5, and the shaft sleeve 6. The two ends of the bracket 4 are fixed by a bracket fixing clamp, and a loading device is arranged above the swing arm support 2. The loading device includes a loading disc 1000 and a pressure sensor 1001 located on the loading disc 1000.

[0076] Further, the specific steps of step S3 are as follows: build a crush-type wiper shaft sub-test system; fix the bracket through the bracket fixing clamp; load the loading disc at a constant speed of 1mm / s perpendicular to the swing shaft; the gasket 5 is crushed and broken, and then the swing shaft 3 and the swing arm support 2 slide along the axis direction of the bracket 4. The crush distance is determined by the distance between the lower end surface of the swing arm support 2 and the upper end surface of the bracket 4. The loading distance is the actual measured crush distance. The pressure F-time t curve of the wiper shaft crush process is extracted by the pressure sensor on the loading disc. The pressure F-displacement S curve is obtained by combining the loading speed displacement S-time t relationship. Repeat the test more than 6 times, remove the abnormal curves, and average the other curves. The processed curve is defined as the material curve of the spring in the simulation model.

[0077] Further, the step S4 is as follows:

[0078] The assembly is self-contacted, the LS_DYNA control card is *AUTOMATIC_SINGLE_SURFACE, the contact between the swing shaft and the support is established separately, and the control card is *AUTOMATIC_SURFACE_TO_SURFACE; the simulation calibration of the crushing process is realized by adjusting the static friction coefficient (FS) and the dynamic friction coefficient (FD) between the swing shaft and the support, until the fitting degree of the force-displacement curve output by the simulation spring and the crushing force-displacement curve of the test reaches more than 90%, and the simulation model is established.

[0079] Embodiment 1

[0080] The embodiment provides a simulation modeling method for a pedestrian protection crushable wiper shaft, as shown in Figure 1 The simulation method flowchart includes model structure simplification, mesh division, material definition and relative motion constraint, and simulation model establishment; wherein the structure simplification includes canceling the original complex structure (gasket 5, shaft sleeve 6), as shown in Figure 3 The remaining glue cap simulation model 10, swing arm support simulation model 20, swing shaft simulation model 30, support model 40 and connecting rod model 70 are reserved, the redundant structure model is reduced, and the calculation efficiency is improved; the mesh division in the simulation method flowchart includes swing arm support and swing shaft outer shell modeling, glue cap, support and connecting rod, etc. Abstract surface modeling, reduce interference jam caused by grid quality problems; the material definition in the simulation method flowchart includes that the definition of spring material parameters is obtained from the spring stiffness curve, and the spring stiffness curve is obtained through the crushable wiper shaft sub-test system; the swing arm support, the swing shaft and the support are assigned rigid materials to avoid abnormal flexible deformation caused by grid quality problems, affect the accuracy of the crushing distance, and other structures are defined according to the actual material characteristics; the relative motion constraint in the simulation method flowchart, the swing shaft is fixedly connected with the swing arm support, nodes are established at the center 201 of the swing arm support limiting surface and the center 401 of the support crushing limiting surface respectively, as shown in Figure 4 A Cylindrical moving pair 100 is established between the two nodes to define the coaxial relative sliding relationship between the swing shaft and the support; the establishment of the simulation model in the simulation method flowchart includes that a spring is established between the swing arm support limiting surface center 201 and the support crushing limiting surface center 401 two nodes, as shown in Figure 4 The spring is used to replace the gasket 5 to simulate the crushing process, wherein the stiffness curve of the spring is defined by the crushable wiper shaft sub-system test.

[0081] Embodiment 2

[0082] As shown in Figure 2As shown, it is a kind of pedestrian protection crush type wiper shaft structure, mainly by rubber cap 1, swing arm support 2, swing shaft 3, support 4, gasket 5, shaft sleeve 6 and connecting rod 7 are constituted, the top of swing shaft 3 is threadedly connected with swing arm support 2, the bottom of swing shaft 3 is threadedly connected with connecting rod 7, swing shaft 3 is installed on support 4, shaft sleeve 6 is sleeved on the shaft, gasket 5 is arranged between swing shaft 3 and support 4;

[0083] In combination with a kind of pedestrian protection crush type wiper shaft structure to build crush type wiper shaft sub-test system, remove rubber cap 1, connecting rod 7, retain other structures to carry out test, as follows: including swing arm support 2, swing shaft 3, support 4, gasket 5 and shaft sleeve 6;As shown in Figure 5 The two ends of support 4 are fixed by support fixing clamp 1002 and 100, loading device is arranged above swing arm support 2, and the loading device includes loading disc 1000 and pressure sensor 1001 on loading disc 1000.

[0084] Specific test method is as follows: as shown in Figure 5 The support is fixed by support fixing clamp, loading disc is loaded along the direction perpendicular to swing shaft at constant speed of 1mm / s, gasket 5 is crushed, then swing shaft 3 along with swing arm support 2 slides along the axis direction of support 4, the crushing distance is determined by the distance between the lower end surface of swing arm support 2 and the upper end surface of support 4, the loading distance is the actual measured crushing distance, the pressure F-time t curve of wiper shaft crushing process is extracted by pressure sensor on loading disc, and the pressure F-displacement S curve is obtained by converting the displacement S-time t relationship, as shown in Figure 6 The test is repeated more than 6 times, the abnormal curve is removed, and the average value of other curves is processed, and the processed curve is defined as the material curve of spring in simulation model.

[0085] Example 3

[0086] Figure 8 It is a structural schematic diagram of a computer device in the embodiment 3 of the present application. Figure 8 A block diagram of an exemplary computer device 12 suitable for implementing embodiments of the present application is shown. Figure 8 The computer device 12 shown is merely an example, and should not bring any limitation to the function and use range of the embodiment of the present application.

[0087] As shown in Figure 8 The computer device 12 is shown in the form of a general-purpose computing device. The components of the computer device 12 can include, but are not limited to, one or more processors or processing units 16, system memory 28, and a bus 18 connecting different system components, including system memory 28 and processing unit 16.

[0088] Bus 18 represents one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, a graphics acceleration bus, a processor or local bus using any of a variety of bus architectures. By way of example, these architectures include Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus.

[0089] Computer device 12 typically includes a variety of computer system readable media. Such media can be any available media that is located either internally or externally to computer device 12, including both volatile and nonvolatile media, removable and non-removable media.

[0090] System memory 28 can include computer system readable media in the form of volatile memory, such as random access memory (RAM) 30 and / or cache memory 32. Computer device 12 can further include other removable / non-removable, volatile / non-volatile computer system storage media. By way of example only, storage system 34 can be provided for reading from and writing to a non-removable, non-volatile magnetic media (not shown and typically called a "hard drive"). Figure 7 Although not shown, a magnetic disk drive can also be utilized in some embodiments to read from and write to a removable, non-volatile magnetic disk (e.g., a "floppy disk"), and an optical disk drive can be utilized in some embodiments for reading from and writing to a removable, non-volatile optical disk (e.g., a CD-ROM, DVD-ROM or other optical media). In these instances, each can be connected to bus 18 by one or more data media interfaces. Memory 28 can include at least one program product having a set (e.g., at least one) of program modules that are configured to carry out the functions of embodiments of the application. Figure 7 Program / utility 40, having a set (at least one) of program modules 42, can be stored in memory 28 by way of example, and not limitation, as well as an operating system, one or more application programs, other program modules, and program data, each or some combination thereof, can include implementation of a networking environment. Program modules 42 generally carry out the functions and / or methodologies of embodiments of the application as described herein.

[0091]

[0092] ​Computer device 12 can also communicate with one or more external devices 14 such as a keyboard, a pointing device, a display 24, etc.; one or more devices that enable a user to interact with computer device 12; and / or any devices (e.g., network card, modem, etc.) that enable computer device 12 to communicate with one or more other computing devices. Such communication can occur via Input / Output (I / O) interface(s) 22. Still yet, computer device 12 in this example can communicate with one or more networks (such as a local area network (LAN), a wide area network (WAN), and / or the Internet) via network adapter 20. As an example, network adapter 20 can include a modem, a network card (wireless or wired), or other well-known interface devices. As depicted, network adapter 20 communicates with the other components of computer device 12 via bus 18. It should be appreciated that although not shown, other hardware and / or software modules could be used in conjunction with computer device 12. Such as, but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data archival storage systems, etc.

[0093] Processing unit 16, through running programs stored in system memory 28, performs various function applications and data processing, such as implementing a simulation modeling method for a pedestrian protection crushable wiper shaft according to embodiments of the present application.

[0094] Embodiment 4

[0095] Embodiment 4 of the present application provides a computer readable storage medium, which has stored thereon a computer program, and the program, when executed by a processor, implements a simulation modeling method for a pedestrian protection crushable wiper shaft according to all embodiments of the present application.

[0096] Any combination of one or more computer readable medium can be utilized. The computer readable medium can be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium can be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium can be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

[0097] A computer readable signal medium can include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal can take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium can be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

[0098] Program code embodied on a computer readable medium can be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0099] Computer program code for carrying out operations of the present application can be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code can execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection can be made to an external computer (for example, through the Internet using an Internet Service Provider). In an embodiment, the present application is directed to computer program products comprising machine-readable media for carrying or having machine-executable instructions or programs

[0100] The preferred embodiments of the present application are described in detail above with reference to the drawings, but the present application is not limited to the specific details of the above-described embodiments. Various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0101] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, various possible combinations are not described again by the present application.

[0102] In addition, various different embodiments of the present application can also be combined in any appropriate manner, as long as they do not deviate from the idea of the present application, and they should also be considered as disclosed by the present application.

Claims

1. A method of simulation modeling for pedestrian protection of crushable wiper shaft, characterized in that, Specifically comprising the following steps: Step S1: model structure simplification: Using spring unit to replace gasket modeling; Step S2: meshing: Establishing the finite element simulation model of the crushing component; Step S3: material definition and relative motion constraint: Material definition includes the definition of spring material parameters obtained from the spring stiffness curve, and the spring stiffness curve is obtained through the crushing wiper shaft sub-test system; the swing arm support, swing shaft and support are defined as rigid materials; The relative motion constraint includes establishing nodes at the centers of the swing arm support limiting surface and the support limiting surface, respectively, and establishing a cylindrical moving pair between the two nodes to define the coaxial relative sliding relationship between the swing shaft and the support, and using rigid connection to simulate threaded connection; Step S4: establishment of simulation model: Defining the contact relationship between the swing shaft and the support separately, and adjusting the parameter static friction coefficient FS and dynamic friction coefficient FD to realize the establishment of a high-precision simulation model; In step S1, the DISCRETE spring unit in LS_DYNA software is used to simulate the crushing and falling process instead of gasket, the DISCRETE ELEMENT TYPE is set to Displacement, and the MAT_S08 SPRING_INELASTIC material card is used to define the spring parameters. The parameters that need to be calibrated in this material card are LCFD force-displacement curve; The finite element simulation model of the crushing component in step S2 includes the simulation model of the rubber cap (10), the simulation model of the swing arm support (20), the simulation model of the swing shaft (30), the support model (40), the connecting rod model (70), the cylindrical moving pair simulation model (100) and the spring simulation model (101); The step S2 is specifically as follows: The wiper shaft and the swing arm support are modeled as an outer shell, with the surface location defined as the top surface and the thickness defined as 1mm; the support is modeled as an extracted surface, with the surface location defined as the center surface and the thickness defined as twice the distance from the support surface to the outer surface of the wiper shaft, and the material defined as MAT_020RIGID; the remaining structures are defined according to the actual material and thickness, and the grid base size is 2mm; The step S3 includes the following steps: Step S31: building a crushing wiper shaft sub-test system; Step S32: simulating the constant speed loading perpendicular to the swing shaft for crushing test; Step S33: extracting the pressure F-time t curve of the wiper shaft crushing process, and converting the loading speed displacement S-time t relationship to obtain the pressure F-displacement S curve; Step S34: repeating step S33 multiple times, removing the abnormal curve in the pressure F-displacement S curve, removing the other curves except the abnormal curve, and processing the average value, the processed curve is defined as the spring stiffness curve in the simulation model; Step S35: rigidly processing the swing arm support, wiper shaft and support in the simulation model, and defining the material as MAT_020RIGID, and defining the other structures according to the actual material; Step S36: the relative motion relationship between the wiper shaft and the bracket is defined by JOINT_CYLINDRICAL, the threaded connection between the swing arm support (2) and the swing shaft (3) is rigidly locked by RIGID_BODIES, and the threaded connection between the swing shaft (3) and the connecting rod (7) is rigidly connected by EXTRA_NODES; Step S31: the sub-test system of the crushable wiper shaft is built, and the specific steps are as follows: a crushable wiper shaft assembly is prepared, the connecting rod (7) and the rubber cap (1) are removed, and the remaining structures are retained, including the swing arm support (2), the swing shaft (3), the bracket (4), the crushable gasket (5), and the shaft sleeve (6); the two ends of the bracket (4) are fixed by a bracket fixing clamp, and a loading device is arranged above the swing arm support (2); the loading device includes a loading disc (1000) and a pressure sensor (1001) located on the loading disc (1000); The specific steps of step S3 are as follows: A sub-test system of the crushable wiper shaft is built; the bracket is fixed by a bracket fixing clamp, the loading disc is loaded in a direction perpendicular to the swing shaft at a constant speed of 1mm / s, the gasket (5) is crushed, and then the swing shaft (3) and the swing arm support (2) slide along the axis direction of the bracket (4), the crushing distance is determined by the distance between the lower end surface of the swing arm support (2) and the upper end surface of the bracket (4), the loading distance is the actual crushing distance, the pressure F-time t curve of the wiper shaft crushing process is extracted by the pressure sensor on the loading disc, the pressure F-displacement S curve is obtained by comprehensively considering the loading speed displacement S-time t relationship, and the simulation model is defined as the spring stiffness curve after repeated tests for more than 6 times, removal of abnormal curves in the pressure F-displacement S curve, and average processing of other curves after removal of the abnormal curves; The specific steps of step S4 are as follows: The assembly is self-contacted, the LS_DYNA control card is *AUTOMATIC_SINGLE_SURFACE, the contact between the swing shaft and the bracket is established separately, and the control card is *AUTOMATIC_SURFACE_TO_SURFACE; the simulation calibration of the crushing process is realized by adjusting the static friction coefficient FS and the dynamic friction coefficient FD between the swing shaft and the bracket until the fitting degree of the force-displacement curve output by the simulation spring and the crushing force-displacement curve of the test reaches more than 90%, and the simulation model is established. 2.A computer device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor implements the simulation modeling method for the crushable wiper shaft for pedestrian protection according to claim 1 when executing the program. 3.A computer readable storage medium having a computer program stored thereon, wherein the program is executed by a processor to implement the simulation modeling method for the crushable wiper shaft for pedestrian protection according to claim 1.

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