Modeling method, device, storage medium and simulation method of active front cover

Abstract

The application discloses a modeling method and device of an active front cover, a storage medium and a simulation method, and comprises the following steps: establishing an inner rod of a detonator by using a rigid connection unit model according to an active front cover structure, and establishing an outer rod of the detonator by using the rigid connection unit model; a motion mechanism between the inner rod and the outer rod of the detonator is established by using a motion joint unit material model; a force-displacement curve of a test detonator measured in a single detonator point explosion test is received and imported into the motion joint unit material model of the motion mechanism between the inner rod and the outer rod; and a shell unit model is used to establish a first locking mechanism between the inner rod and the outer rod of the detonator. The actual test data of the single detonator is imported, the motion joint unit material model is used for the motion mechanism between the inner rod and the outer rod of the detonator, and therefore the accuracy of the modeling of the active front cover is improved.

Description

Technical Field

[0001] This invention relates to the technical field of automotive hoods, and more specifically, to a modeling method, device, storage medium, and simulation method for an active hood. Background Technology

[0002] In China, the protection of vulnerable pedestrians on roads is gradually gaining attention, and various safety standards are increasingly incorporating pedestrian protection content and becoming more stringent, such as CNCAP and CIASI. Mandatory national standards will also be established in the future. To address pedestrian safety issues, active front cover technology has emerged. In existing technologies, simulation technology is used in the development of active front covers. There are two main methods for establishing the detonator structure during modeling: one is to build the detonator structure as an indeformable rigid body, disregarding its internal mechanical properties. While this meets development requirements, the model is inaccurate, leading to over-design and increased development costs. The other method is to build a gas model inside the detonator cavity, automatically adjusting the internal pressure based on gas volume changes, but this cannot accurately represent the detonator's movement during actual use. Summary of the Invention

[0003] To address at least one aspect of the above problems, the present invention provides a modeling method, device, storage medium, and simulation method for an active front cover.

[0004] In a first aspect, this application provides a modeling method for an active front cover, comprising the following steps: based on the active front cover structure, establishing the inner rod of the detonator using a rigid connection unit model, and establishing the outer rod of the detonator using a rigid connection unit model; establishing the motion mechanism between the inner rod and the outer rod of the detonator using a motion joint unit material model; receiving the force-displacement curve of the test detonator obtained from a separate detonator ignition test, and importing it into the motion joint unit material model of the motion mechanism between the inner rod and the outer rod; and establishing the first locking mechanism between the inner rod and the outer rod of the detonator using a shell unit model.

[0005] Preferably, the method further includes the following steps: based on the active front cover structure and its deformation design, for deformable sheet metal mechanisms, a neutral surface two-dimensional unit model is used for modeling, and a corresponding material model is assigned according to the sheet metal material, wherein the parameters in the material model include density, Poisson's ratio, elastic modulus, yield strength, fracture strength, and true stress-strain curve; for non-deformable sheet metal mechanisms, a rigid connection unit model is used for modeling.

[0006] More preferably, the material model of the deformable plate mechanism adopts an elastoplastic isotropic thin-shell material model; in the elastic deformation stage, the shear modulus of the material model is calculated by the shear modulus formula; in the plastic deformation stage, the material model is characterized by the true stress-strain curves at different preset rates.

[0007] Preferably, the method further includes the following steps: the bolts are modeled using a two-dimensional element model of the outer surface; based on the active front cover structure, for fixed bolts, a rigid connection element model is used to model the connection of the fixed bolts; for hinged bolts, a motion joint element model is used to model the connection of the hinged bolts; and for sliding bolts, a relative motion model with sliding interface contact is used to model the connection of the sliding bolts.

[0008] Preferably, the motion joint unit material model used to establish the motion mechanism between the inner rod and the outer rod is a motion joint unit material model with torque resistance.

[0009] Preferably, the force-displacement curve is a force-displacement curve that is symmetrical about the y-axis.

[0010] Preferably, the motion joint unit material model of the motion mechanism between the inner rod and the outer rod of the detonator only releases one rotational degree of freedom and one translational degree of freedom of the rigid connection unit model relative to the inner rod.

[0011] Secondly, this application provides a simulation method for an active front cover, including the steps of: importing the active front cover model into a pedestrian head-collision finite element simulation model, wherein the active front cover model is modeled using any of the active front cover modeling methods described above.

[0012] Thirdly, this application provides a modeling device for an active front cover, the device including a memory and a processor, the memory storing a computer program that, when executed by the processor, implements the modeling method for an active front cover as described above.

[0013] Fourthly, this application provides a storage medium storing computer-readable instructions that, when executed by a processor, perform the method described in any of the preceding claims.

[0014] The modeling method, device, storage medium, and simulation method for an active front cover of the present invention have the following beneficial effects:

[0015] (1) In the process of modeling the detonator structure, a motion joint element material model was adopted, and the force-displacement curve of the test detonator obtained from the detonation test of the individual detonator was imported into this model. This allows the detonator part of the active front cover model of this application to accurately simulate the motion state of the detonator in the actual process during the simulation, which helps to improve the accuracy of the model. Furthermore, the use of a motion joint element material model instead of the gas element modeling method in the prior art can improve the model calculation speed. When the detonator structure is adjusted, the model adjustment can be quickly completed by simply importing the force-displacement curve of the test detonator obtained from the detonation test of the individual detonator of the new detonator into this model. This is faster than other modeling methods.

[0016] (2) This application only needs to accurately model the key structures and motion forms of the active front cover. For example, the deformable plate structure, movable hinge structure and detonator structure of the active front cover in the pedestrian head impact test are accurately modeled. For structures that will not deform in the actual test, such as the inner and outer rods of the detonator, bolts and other structures, the model size of the active front cover model is reduced to the greatest extent, unnecessary interference terms are reduced, and the accuracy and calculation speed of the model are improved. Attached Figure Description

[0017] To better understand the above and other objects, features, advantages, and functions of the present invention, reference can be made to the embodiments shown in the accompanying drawings. The same reference numerals in the drawings refer to the same parts. Those skilled in the art should understand that the drawings are intended to schematically illustrate preferred embodiments of the invention and do not limit the scope of the invention in any way; the parts in the drawings are not drawn to scale.

[0018] Figure 1 A flowchart of a modeling method for an active front cover according to an embodiment of the present invention is shown;

[0019] Figure 2 A schematic diagram of the detonator is shown;

[0020] Figure 3 A schematic diagram of the detonator modeling method of an active front cover according to an embodiment of the present invention is shown;

[0021] Figure 4 A schematic diagram of an initiator model of a modeling method for an active front cover according to an embodiment of the present invention is shown.

[0022] Figure 5 A first schematic diagram of the detonator model calculation of a modeling method for an active front cover according to an embodiment of the present invention is shown;

[0023] Figure 6A second schematic diagram of the detonator model calculation of a modeling method for an active front cover according to an embodiment of the present invention is shown;

[0024] Figure 7 The true stress-strain curve of a modeling method for an active front cover according to an embodiment of the present invention is shown.

[0025] Figure 8 A schematic diagram of the linkage mechanism is shown.

[0026] Explanation of reference numerals in the attached figures:

[0027] 11. Inner rod; 12. Outer rod; 13. First connecting piece; 14. Second connecting piece; 15. First locking mechanism; 16. Hinge plate; 17. Fixing bolt; 21. Main hinge arm; 22. Upper hinge arm; 23. Hinge chain; 24. Second locking mechanism; 25. Sliding bolt; 26. Hinge bolt. Detailed Implementation

[0028] The exemplary embodiments of this disclosure are described below with reference to the accompanying drawings, including various details of the embodiments to aid understanding, and 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 disclosure. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0029] The term "comprising" and its variations as used herein signify open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "at least partially based on". The terms "one example embodiment" and "one embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first", "second", etc., may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0030] To at least partially address one or more of the aforementioned problems and other potential issues, embodiments of this disclosure propose a first aspect: this application provides a modeling method for an active front cover, such as... Figures 1 to 8 As shown, the active front cover includes an initiator mechanism, a linkage hinge mechanism, a deformable plate mechanism, and a non-deformable plate mechanism; as Figure 2 As shown, the detonator mechanism includes an inner rod, an outer rod, a first connecting member, a second connecting member, a first locking mechanism, a hinge plate, and fixing bolts; as Figure 8As shown, the linkage mechanism includes a main hinge arm, an upper hinge arm, a hinge chain, a second locking mechanism, a sliding bolt, and a hinge bolt; a deformable plate mechanism refers to a mechanism that deforms during a pedestrian head-impact test, while a non-deformable plate mechanism refers to a mechanism that does not deform during a pedestrian head-impact test.

[0031] The method described in this application includes the following steps:

[0032] Based on the active front cover structure, the inner rod of the detonator is established using a rigid connection unit model, and the outer rod of the detonator is established using a rigid connection unit model; specifically, as follows... Figure 3 and Figure 4 As shown, the inner rod is modeled using a rigid connection unit model and labeled as rigid connection unit R5; the outer rod, the first connector, and the second connector are modeled using a single rigid connection unit model and labeled as rigid connection unit R6.

[0033] A motion mechanism between the inner and outer rods of the detonator is established using a motion joint element material model, denoted as motion joint element K5. Preferably, the motion joint element material model used to establish the motion mechanism between the inner and outer rods is a motion joint element material model with torque resistance, wherein the parameters in the material model include the force-displacement curve of the test detonator obtained from a separate detonator ignition test. Specifically, as shown... Figure 4 As shown, the two end nodes of the motion joint unit K5 are N51 and N52, respectively. N51 and N52 are the connection points on the rigid connection unit R5 and the rigid connection unit R6, respectively. In the simulation software, the spatial position relationship of the motion joint unit K5 is defined by the local coordinate system Frame51, and the motion type is given by the NTYP parameter, which is CYLINDRICAL. The relative motion mode between the rigid connection unit R5 and the rigid connection unit R6 is determined by the motion joint unit K5. The motion joint unit K5 has three translational degrees of freedom r51, s51, t51 and three rotational degrees of freedom φ51, φ52, φ53. Preferably, the motion joint unit material model K5 of the motion mechanism between the inner rod and the outer rod of the detonator only releases one rotational degree of freedom φ51 and one translational degree of freedom r51 relative to the rigid connection unit model R5 of the inner rod, so that the inner rod and the outer rod of the detonator can generate relative motion in a real movable manner.

[0034] The force-displacement curve of the test detonator, obtained from a separate detonator ignition test, is received and imported into the material model of the motion joint unit of the motion mechanism between the inner and outer rods; preferably, the force-displacement curve adopts a force-displacement curve symmetrical about the y-axis, such as... Figure 5 and Figure 6As shown, in actual use, the locking mechanism causes only the positive or negative half of the Y-axis to function. Which half functions depends directly on the local coordinate system and the way the motion joint units are established. Due to the variety of these forms, to ensure safety redundancy and that the model in this application can produce the correct motion under various conditions, the force-displacement curve inside the detonator is set to be symmetrical about the Y-axis. When the detonator is changed, the force-displacement curve of the test detonator obtained from the individual detonator ignition test of the new detonator can be quickly imported into the motion joint unit material model of the motion mechanism between the inner and outer rods, allowing for rapid model adjustment compared to other modeling methods.

[0035] A shell element model was used to establish the first locking mechanism between the inner rod and the outer rod of the detonator. The pressure inside the detonator cavity is extremely high. Without this first locking mechanism, the inner rod would fly out of the outer rod. Therefore, in order to realistically simulate the actual situation, a shell element model was used to establish the first locking mechanism between the inner rod and the outer rod of the detonator, so that it is consistent with the actual state.

[0036] In a preferred embodiment, this application further includes the following steps: based on the active front cover structure and its deformation design, for the non-deformable sheet metal mechanism, a rigid connection unit model is used for modeling; for the deformable sheet metal mechanism, a neutral surface two-dimensional unit model is used for modeling, and a corresponding material model is assigned according to the sheet metal material, wherein the parameters in the material model include density, Poisson's ratio, elastic modulus, yield strength, fracture strength, and true stress-strain curve. Preferably, the material model for the deformable sheet metal mechanism adopts an elastoplastic isotropic thin shell material model, and in the elastic deformation stage, the shear modulus of the material model is calculated using the shear modulus formula.

[0037] ,

[0038] Where G represents the shear modulus, E represents the elastic modulus, and v represents Poisson's ratio. During the plastic deformation stage, the material model is characterized by true stress-strain curves at different preset rates. Preferably, the number of component points in the true stress-strain curves at different rates is equal, such as... Figure 7 As shown, the horizontal axis represents strain, and the vertical axis represents true stress.

[0039] In a preferred embodiment, this application further includes the following step: the bolt is modeled using a two-dimensional element model of its outer surface, based on the active front cover structure, such as... Figure 8As shown, the main hinge arm, upper hinge arm, and hinge chain are modeled using a two-dimensional shell element model; for the fixed bolt, the connection point of the fixed bolt is modeled using a rigid connection element model; for the hinge bolt, the connection point of the hinge bolt is modeled using a motion joint element model; and for the sliding bolt, the connection point of the sliding bolt is modeled using a relative motion model with sliding interface contact.

[0040] This application also provides a simulation method for an active front cover, including the following steps: importing the active front cover model into a pedestrian head impact finite element simulation model, and obtaining the pedestrian head impact calculation results under the front cover detonation state according to CNCAP requirements through the simulation of the pedestrian head impact finite element simulation model. The results include the internal force change of the detonator and the head injury value, wherein the active front cover model is modeled using any of the active front cover modeling methods described above.

[0041] This application also provides a modeling device for an active front cover, the device including a memory and a processor, the memory storing a computer program that, when executed by the processor, implements the modeling method for an active front cover as described above.

[0042] This application also provides a storage medium storing computer-readable instructions that, when executed by a processor, perform the method described in any of the preceding claims.

[0043] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand this document.

Claims

1. A modeling method for an active front cover, characterized in that: Includes the following steps: Based on the active front cover structure, the inner rod of the detonator is established using a rigid connection unit model, and the outer rod of the detonator is established using a rigid connection unit model. A motion mechanism between the inner and outer rods of the detonator was established using a material model of a motion joint unit. Receive the force-displacement curve of the test detonator obtained from the individual detonator ignition test, and import it into the material model of the motion joint unit of the motion mechanism between the inner rod and the outer rod; The first locking mechanism between the inner and outer rods of the detonator is established using a shell element model.

2. The modeling method for an active front cover according to claim 1, characterized in that: It also includes the following steps: Based on the active front cover structure and its deformation design, for deformable sheet metal mechanisms, a neutral surface two-dimensional element model is used for modeling, and a corresponding material model is assigned according to the sheet material. The parameters in the material model include density, Poisson's ratio, elastic modulus, yield strength, fracture strength, and true stress-strain curve. For non-deformable sheet metal mechanisms, a rigid connection element model is used for modeling.

3. The modeling method for an active front cover according to claim 2, characterized in that: The material model for the deformable sheet metal mechanism adopts an elastoplastic isotropic thin-shell material model; in the elastic deformation stage, the shear modulus of the material model is calculated using the shear modulus formula; in the plastic deformation stage, the material model is characterized by true stress-strain curves at preset rates.

4. The modeling method for an active front cover according to claim 1, characterized in that: It also includes the following steps: Bolts are modeled using a two-dimensional element model of the outer surface. Based on the active front cover structure, for fixed bolts, a rigid connection element model is used to model the connection of the fixed bolts; for hinged bolts, a motion joint element model is used to model the connection of the hinged bolts; and for sliding bolts, a relative motion model with sliding interface contact is used to model the connection of the sliding bolts.

5. The modeling method for an active front cover according to claim 1, characterized in that: The motion joint element material model used to establish the motion mechanism between the inner and outer rods is a motion joint element material model with torque resistance.

6. The modeling method for an active front cover according to claim 1, characterized in that: The force-displacement curve is a force-displacement curve that is symmetrical about the y-axis.

7. The modeling method for an active front cover according to claim 1, characterized in that: The motion joint unit material model of the motion mechanism between the inner and outer rods of the detonator only releases one rotational degree of freedom and one translational degree of freedom relative to the rigid connection unit model of the inner rod.

8. A simulation method for an active front cover, characterized in that: The steps include: importing the active front cover model into the pedestrian head-collision finite element simulation model, wherein the active front cover model is modeled using the active front cover modeling method described in any one of claims 1 to 7.

9. A modeling device for an active front cover, characterized in that: The device includes a memory and a processor, wherein the memory stores a computer program that, when executed by the processor, implements a modeling method for an active front cover according to any one of claims 1 to 7.

10. A storage medium, characterized in that: It stores computer-readable instructions that, when executed by a processor, perform the method according to any one of claims 1-7.

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