Finite element modeling method for chest impactor or dummy two-dimensional displacement sensor
By performing differentiated mesh generation and material settings for the slide rail sleeve and support of the IR-TRACC sensor, and combining BEAM element connection and self-contact simulation, the problems of motion trajectory deviation and inaccurate mass distribution in existing modeling were solved, realizing accurate simulation and efficient data output of the sensor under dynamic impact environment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA AUTOMOTIVE ENG RES INST
- Filing Date
- 2026-03-20
- Publication Date
- 2026-06-23
AI Technical Summary
Existing finite element modeling methods cannot accurately simulate the real motion trajectory and mass distribution of IR-TRACC sensors under dynamic impact environments, resulting in insufficient accuracy in chest injury assessment and an inability to accurately calculate two-dimensional displacement and rotation data.
Shell elements are used to divide the slide rail sleeve, solid elements are used to divide the branch seats, and BEAM elements are combined with self-contact settings to simulate the composite motion and contact relationship of the sensor. Two-dimensional displacement data is output through DISCRETE elements and analyzed in conjunction with an explicit dynamic solver.
It achieves accurate reproduction of the mass distribution and inertial characteristics of the sensor during dynamic compression, improves the realism and credibility of the simulation results, and enhances the accuracy of chest injury assessment.
Smart Images
Figure CN122263508A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of finite element modeling technology, specifically to a finite element modeling method for a chest impactor or a dummy two-dimensional displacement sensor. Background Technology
[0002] In the fields of automotive crash safety, drop testing, and biomechanics research, dummies and chest impact testers are key tools for assessing the risk of human injury. Particularly in chest injury assessment, the amount of compression deformation of the thoracic cavity is a core indicator for determining the risk of rib fractures and internal organ damage. Photoelectric displacement sensors are typically used to measure the compression displacement of the ribs in the thoracic cavity to indirectly reflect the risk of rib fractures.
[0003] In recent years, IR-TRACC (Infrared Telescopic Displacement Sensor) has been widely used in dummy chest or impactor measurement systems. Compared with traditional photoelectric displacement sensors, IR-TRACC has significant advantages: its measurement point has a larger range of free movement relative to the reference point, and it has multi-degree-of-freedom angular deflection capability, enabling it to simultaneously output one-dimensional compressive displacement and multi-dimensional rotational angle data. Furthermore, this sensor exhibits high signal transmission stability and strong anti-interference capabilities, making it ideal for operation in highly dynamic impact environments.
[0004] However, existing sensor modeling methods face significant technical bottlenecks when using finite element analysis (FEA) for virtual calibration and damage prediction of dummies or impactors. Current finite element models typically employ a highly simplified approach: using only one-dimensional bar / rod elements or spring elements to directly connect the measurement point and the reference point, simulating the sensor's compression through the axial deformation of the elements.
[0005] This simplified modeling strategy leads to the following serious technical flaws: First, geometric and mass characteristics are lacking. Existing models do not establish the true geometric shape and mass distribution of the sensor's internal components in detail, only abstracting them as massless connecting rods. This causes the model to fail to accurately reflect the inertial effects of the sensor during dynamic impact processes, especially at high frequencies, where inaccurate mass distribution can significantly affect the transmission path of acceleration and force.
[0006] Second, the motion constraints and contact relationships are distorted. The actual sensor's measurement point extends and retracts within the slide rail, accompanied by complex friction, self-contact, and hinge rotation. Simple one-dimensional unit connections cannot simulate the extension and retraction guiding mechanism of the slide rail sleeve, the contact friction between the sleeve and the slide rail, and the rotational constraints between supports. This prevents the model from reproducing the sensor's true motion trajectory under non-axial loads, resulting in deviations between the output displacement and rotation angle data and the physically measured values.
[0007] Third, the multidimensional data output capability is insufficient. Existing models cannot accurately calculate the two-dimensional displacement components and angular deflection of the measurement point relative to the reference point. Relying solely on the length change of a one-dimensional element cannot distinguish between pure compressive displacement and displacement components caused by angular deflection, thus reducing the accuracy of chest injury assessment. Summary of the Invention
[0008] The purpose of this invention is to propose a finite element modeling method for a two-dimensional displacement sensor for a chest impactor or dummy. This technical solution can accurately reproduce the actual working state of the sensor while ensuring the accuracy of mass distribution during dynamic compression.
[0009] To achieve the above objectives, in a first aspect, the present invention proposes a finite element modeling method for a two-dimensional displacement sensor of a chest impactor or dummy, comprising: Geometric modeling and mesh generation are performed on the slide rail sleeve, support, and other components respectively; the slide rail sleeve is meshed using shell elements, and the support is meshed using solid elements; The slide rail sleeve is made of an elastic-plastic material, and the support is made of a rigid material; Nodes are arranged at the measurement point, the front end of the slide rail sleeve, and inside the support. The nodes on the measurement point, slide rail sleeve, and support are connected by BEAM elements to simulate the telescopic movement of the slide rail sleeve. The movement trajectory of the slide rail sleeve is controlled by directional BEAM elements. Hinges that can only rotate around the Z-axis are set between the supports. BEAM elements are used to connect the components at the rotating joint and set the corresponding stiffness. The slide rail sleeve is equipped with self-contact to enable telescopic movement; Discrete units are established from the measurement points to the centers of different supports to output one-dimensional or two-dimensional compression displacement data and rotation angle data; Based on the obtained compression and rotation data, the two-dimensional displacement components of the measurement point relative to the reference point are calculated.
[0010] The beneficial effects of the basic scheme are: differentiated meshing is performed by using shell elements for the slide rail sleeve and solid elements for the support, which realizes the accurate restoration of the structural geometry and mechanical properties, strictly ensures that the mass distribution and inertial characteristics during dynamic compression are highly consistent with the actual structure, improves the authenticity and credibility of the simulation results, and provides a reliable foundation for subsequent mechanical and motion analysis.
[0011] The slide rail sleeve is made of an elasto-plastic material, which can accurately simulate its stress deformation, yielding, and springback characteristics; the support is made of a rigid material to ensure the stiffness and positioning accuracy of the support end. The two materials work together to avoid simulation distortion caused by the use of a single material, and while ensuring the overall structural stability, they maximize the reproduction of the actual movement flexibility of the slide rail, greatly improving the accuracy of the mechanical response and movement process.
[0012] By arranging key nodes at the measurement point, the front end of the sleeve, and inside the support and connecting them with BEAM units, and strictly controlling the motion trajectory with directional BEAM units, and setting hinges that rotate only around the Z-axis between the supports, and giving the rotating pair reasonable stiffness through BEAM units, it is possible to accurately simulate composite motions such as rotation and extension, solve the problems of limited motion freedom and trajectory deviation from reality in traditional modeling, and fully reproduce the real working state of the sensor / slide rail mechanism.
[0013] By setting self-contact for the slide rail sleeve, the contact, separation and relative sliding between structures during the expansion and contraction process can be realistically simulated, avoiding simulation errors such as unreasonable penetration and rigid interference. At the same time, a discrete element from the measurement point to the support center can be established, which can directly output key data such as compression displacement and rotation angle without the need for additional post-processing extraction, making data acquisition more direct and stable.
[0014] As a feasible and preferred approach, the component geometry modeling and meshing steps include: The slide rail sleeve is divided using quadrilateral shell units, with the mesh being densified in the flanged part and key stress areas of the sleeve. The support is modeled using hexahedral solid elements and uniformly meshed, with the mesh being fined in key stress areas and connection points.
[0015] As a feasible preferred embodiment, the slide rail sleeve is provided with an elastic-plastic material, and the support is provided with a rigid material, including the following: The slide rail sleeve adopts the MAT3 elastoplastic material model, and the parameters of elastic modulus, yield strength and hardening modulus are set; The support adopts the MAT20 rigid material model.
[0016] As a feasible and preferred solution, the connection setup steps include: Each node is connected sequentially by BEAM elements, and multiple BEAM elements are connected to the surface at both ends. BEAM_ORIENTATION elements are created by selecting nodes from the lower and upper end faces.
[0017] As a feasible and preferred option, the hinge configuration includes: The two components at the rotating joint are connected using BEAM units made of material No. 66. Set the rotational stiffness of the BEAM element along the rotational direction of the revolute joint to zero, and assign translational or rotational stiffness to the remaining degrees of freedom; Use the CONSTRAINED_JOINT_STIFFNESS_GENERATION keyword to control the damping and limiting characteristics of the hinge.
[0018] As a feasible preferred embodiment, the slide rail sleeve is provided with self-contact to achieve telescopic movement, including the following: Use CONTACT_AUTOMATIC_SINGLE_SURFACE to set self-contact for the slide rail sleeve; Use the CONSTRAINED_JOINT_STIFFNESS_TRANSLATION keyword to add a force-displacement curve between the components at both ends of the sensor.
[0019] As a feasible and preferred solution, the output setup steps are as follows: One-dimensional measurement is achieved by establishing a low-stiffness DISCRETE element from the measurement point to the fixed support; Two-dimensional measurement is achieved by establishing a low-stiffness DISCRETE element from the measurement point to the rotatable support; Use the DATABASE_HISTORY_DISCRETE keyword to output the spring change.
[0020] As a feasible and preferred solution, the formula for calculating the two-dimensional displacement components is as follows:
[0021]
[0022] in, This is the compression amount in the X direction. This is the compression amount in the Y direction. The angle is the rotation around the Z-axis.
[0023] As a feasible and preferred approach, the relative displacement of the measurement point relative to the reference point is calculated using the following formula: .
[0024] As a feasible preferred option, it also includes: using an explicit dynamic solver to analyze the model, simulating the sensor response during dynamic compression, and verifying the model's rationality. Attached Figure Description
[0025] Figure 1 This is a logical schematic diagram of an embodiment of the present invention.
[0026] Figure 2 This is a schematic diagram of a two-dimensional displacement sensor in an embodiment of the present invention.
[0027] Figure 3 This is a schematic diagram of the node arrangement.
[0028] Figure 4 This is a schematic diagram of the sleeve structure.
[0029] Figure 5 This is a schematic diagram of a hinge model.
[0030] Reference numerals in the attached drawings: First support 1, Second support 2, Third support 3, First revolute joint 4, Second revolute joint 5, Spring unit 6, Slide rail sleeve 7, Measuring point 8, Upper end face 9, Lower end face 10. Detailed Implementation
[0031] To make the technical solution and advantages of this application clearer, the technical solution of the present invention will be further described in detail below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are only some embodiments of the present invention, and are only used to explain this application, not to limit it. It should be noted that the technical features or combinations of technical features described in the following embodiments should not be considered isolated; they can be combined with each other to achieve better technical effects. The same reference numerals appearing in the accompanying drawings of the following embodiments represent the same features or components, and can be applied to different embodiments.
[0032] Furthermore, unless otherwise defined, the technical or scientific terms used in this invention description shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains.
[0033] The present invention will now be described in further detail with reference to the accompanying drawings.
[0034] This embodiment uses Hypermesh, Ansys, or Primer as preprocessing software for geometric modeling and mesh generation, and LS-DYNA or PAM-CRASH as solvers for finite element analysis. This embodiment preferably uses Hypermesh and LS-DYNA. Hypermesh has strong mesh generation capabilities and can efficiently handle complex geometric models; LS-DYNA has strong explicit dynamic analysis capabilities and is suitable for simulating and analyzing sensors during dynamic compression processes.
[0035] The 2D IR-TRACC sensor mainly consists of a support, slide rail sleeve, connecting block, and measuring points. The sensor reflects the compression of the ribs in the thoracic cavity by measuring the displacement and angular deflection of the measuring points relative to a reference point. During the modeling process, the geometry, material properties, and connection methods of each component need to be analyzed in detail to ensure that the model accurately reflects the actual working state of the sensor.
[0036] This disclosure provides a finite element modeling method for a two-dimensional displacement sensor of a chest impactor or dummy, referring to... Figure 1 This includes the following steps.
[0037] Step S100, component geometry modeling and mesh generation, includes: Step S101, Modeling the slide rail sleeve 7, including: Based on the actual dimensions of the slide rail sleeve 7, create its 3D geometric model in Hypermesh. Maintain coaxiality and clearance fit between the segments to ensure the slide rail can slide freely.
[0038] The slide rail sleeve 7 is meshed using quadrilateral shell elements to improve computational efficiency and accuracy. The mesh is appropriately refined in the flanged sections and critical stress areas of the sleeve to capture detailed deformations. Simultaneously, a flanged mesh is created around the front end of the sub-sleeve to prevent the sleeve from slipping inwards during compression.
[0039] Step S102, support modeling, refer to Figure 2 ,include: The supports are modeled using hexahedral solid elements to accurately reflect their structural strength and stiffness. In this embodiment, it includes a first support 1, a second support 2, and a third support 3. Based on the actual shape and size of the supports, their three-dimensional geometric models are created in Hypermesh.
[0040] The supports are uniformly meshed to ensure the mesh quality meets the calculation requirements. The mesh is appropriately refined in critical stress areas and connections to improve the accuracy of local stress analysis.
[0041] Step S103: Model other components. Based on the actual structure of the sensor, perform geometric modeling and mesh generation on other components such as the connecting block (including the first rotating joint 4, the second rotating joint 5, and the spring unit 6) and the measuring point 8 to ensure that the connection relationship and relative position between each component are accurate.
[0042] Step S200, material setup, including: Step S201, Material setting for slide rail sleeve 7: Each section of slide rail sleeve 7 uses elasto-plastic material MAT3 (… The simulation was performed using MAT_PLASTIC_KINEMATIC. This material accurately reflects the elastic deformation and plastic yielding behavior of the slide rail under stress. Key parameters such as the elastic modulus, yield strength, and hardening modulus of the material were set based on actual material properties.
[0043] Step S202, support material setting: the support adopts rigid material MAT20 ( The simulation is performed using MAT_RIGID. Rigid materials ensure structural stability and prevent significant deformation of the support under stress. Based on actual requirements, parameters such as the support's density and elastic modulus are set (although it is a rigid material, the density parameter still needs to be set to meet mass distribution requirements).
[0044] Step S203: Setting materials for other components. Based on actual needs, set corresponding material parameters for other components such as the connecting block and measuring point 8. Ensure that the material properties of each component match the actual situation to accurately simulate the physical behavior of the sensor.
[0045] Step S300, connection settings, including: Step S301, connecting the slide rail sleeve 7, including: Reference Figure 3 Nodes are arranged at measurement point 8, the foremost point of slide rail sleeve 7, and the center of the bottom circle inside the first support 1. Nodes are arranged at the center of the circle according to the position of the lower end face 10 of each section of the sleeve, so that they can be connected later by BEAM elements (beam elements).
[0046] The nodes mentioned above are connected sequentially using BEAM elements to simulate the telescopic movement of the slide rail sleeve 7. Four BEAM elements are connected to the respective surfaces at each of the two end points to determine the travel range of the slide rail sleeve 7.
[0047] Reference Figure 4 Two nodes are selected from the lower end face 10 and corresponding nodes are established to create BEAM_ORIENTATION elements. One node is selected from the upper end face 9 and corresponding nodes are established to create BEAM_ORIENTATION elements. These elements are used to control the direction of the BEAM elements and ensure that the slide sleeve 7 maintains the correct motion trajectory during the extension and retraction process.
[0048] Step S302, hinge setup, refer to Figure 5 A standard Cartesian coordinate system is established, with the Z-axis perpendicular to the direction of chest impact. A hinge that allows rotation only around the Z-axis is installed between the first support 1 and the second support 2. The position of the hinge should be determined based on the actual structure of the sensor to ensure that the rotational freedom meets the design requirements.
[0049] The two components at the revolute joint are connected using BEAM elements made of material #66. In the material card, the rotational stiffness of the BEAM elements along the direction of rotation of the revolute joint is set to 0, while the other five degrees of freedom are given relatively large translational or rotational stiffnesses. This ensures that the hinge can only rotate about the Z-axis, while the degrees of freedom in other directions are restricted.
[0050] use( The `CONSTRAINED_JOINT_STIFFNESS_GENERATION` keyword controls the damping and limiting characteristics of the hinge. The damping coefficient and limiting distance are set according to actual needs to accurately simulate the dynamic response of the hinge in actual operation.
[0051] The stiffness of the rotating joint, motion damping, contact parameters, etc. can all be flexibly adjusted, and it can quickly adapt to various working conditions such as different loads, different impact speeds, and different strokes. Compared with fixed parameter modeling, it has a wider range of applications and stronger fault tolerance, and can meet the mechanism simulation needs under multiple scenarios and working conditions, thus having higher engineering practical value.
[0052] Step S400, Contact Settings, including: Step S401: Self-contact is set for the slide rail sleeve 7. This is done by configuring self-contact (CONTACT_AUTOMATIC_SINGLE_SURFACE) to enable telescopic movement between the slide rail sleeves 7. No friction coefficient is set in the self-contact configuration to reduce the impact of friction on the slide rail movement. Simultaneously, the (CONSTRAINED_JOINT_STIFFNESS_TRANSLATION) keyword is used to add a force-displacement curve between the components at both ends of the sensor, achieving a damping effect during slide rail movement.
[0053] Step S402, Other Contact Settings: Based on the actual structure and operating state of the sensor, set contact settings for other components that may come into contact. Ensure that the contact settings accurately reflect the interaction between components and avoid penetration and unreasonable deformation.
[0054] Step S500, Output Settings, including: Step S501, one-dimensional measurement method: One-dimensional measurement is achieved by establishing a DISCRETE element with stiffness of 0.001 from measurement point 8 to the center of the third support 3. The third support 3 is a rigid body and is connected through ( The MAT_RIGID element is constrained across all degrees of freedom, preventing motion; therefore, this element can only measure one-dimensional stretching. (Using...) The keyword DATABASE_HISTORY_DISCRETE outputs the change in spring temperature, which is the compression displacement.
[0055] Step S502, Two-dimensional measurement method: Two-dimensional measurement is achieved by establishing a DISCRETE element with a stiffness of 0.001 from measurement point 8 to the inner center of the first support 1. The first support 1 can rotate around the Z-axis with the second support 2 according to the set hinge, so this element can measure the two-dimensional expansion and contraction. Similarly, ( The DATABASE_HISTORY_DISCRETE keyword outputs the spring change as a component of the compression displacement.
[0056] Step S503, angle measurement: A DISCRETE element with a stiffness of 0.001 is established between the two hinge components to output the angle change. The stiffness of this measurement element is very small and negligible compared to the stiffness of the hinge; therefore, it can be assumed that this measurement element does not conflict with the force-bearing element. (Through...) The keyword DATABASE_HISTORY_DISCRETE outputs the rotation angle data. Combining the rotation angle data with the compression displacement data provides a comprehensive view of the two-dimensional displacement of measurement point 8 relative to the reference point.
[0057] Step S600, two-dimensional displacement calculation, includes: Step S601: Obtain compression and rotation data. Based on the above output settings, obtain the compression data of measurement point 8 in the X and Y directions and the rotation data around the Z axis as the basis for calculating the two-dimensional displacement.
[0058] Step S602, two-dimensional displacement calculation formula, let the compression of measurement point 8 in the X direction be... The compression in the Y direction is The rotation angle around the Z-axis is (in radians), the two-dimensional displacement components of measuring point 8 relative to the reference point can be calculated using the following formula:
[0059]
[0060] The above formula takes into account the influence of rotation angle on displacement components and can accurately reflect the actual displacement of measurement point 8 in the two-dimensional plane.
[0061] Step S603, relative displacement calculation: Based on actual needs, further calculate the relative displacement of measurement point 8 relative to the reference point. The relative displacement is calculated using the following formula:
[0062] This formula gives the straight-line distance of measurement point 8 relative to the reference point in a two-dimensional plane, providing a direct basis for chest injury assessment.
[0063] Step S700: Model Trial Calculation and Check. After completing all settings, perform a trial calculation of the model. Use the LS-DYNA solver to perform explicit dynamic analysis on the model, simulating the sensor's response during dynamic compression. Observe the model's deformation, stress distribution, and displacement output results to ensure the model functions correctly and provides reasonable results.
[0064] Check the trial calculation results to verify whether the displacement output meets expectations. If any abnormal or unreasonable results are found, the model settings need to be adjusted. Adjustments may include mesh refinement, material parameter correction, and connectivity optimization. Through multiple trial calculations and adjustments, ensure the accuracy and reliability of the model.
[0065] The above content is merely an embodiment of the present invention. Commonly known structures and characteristics of the solutions are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can improve and implement this solution based on the guidance provided in this application and their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.
Claims
1. A finite element modeling method for a two-dimensional displacement sensor of a chest impactor or dummy, characterized in that, include: Geometric modeling and mesh generation are performed on the slide rail sleeve, support, and other components respectively; the slide rail sleeve is meshed using shell elements, and the support is meshed using solid elements; The slide rail sleeve is made of an elastic-plastic material, and the support is made of a rigid material; Nodes are arranged at the measurement point, the front end of the slide rail sleeve, and inside the support. The nodes on the measurement point, slide rail sleeve, and support are connected by BEAM elements to simulate the telescopic movement of the slide rail sleeve. The movement trajectory of the slide rail sleeve is controlled by directional BEAM elements. Hinges that can only rotate around the Z-axis are set between the supports. BEAM elements are used to connect the components at the rotating joint and set the corresponding stiffness. The slide rail sleeve is equipped with self-contact to enable telescopic movement; Discrete units are established from the measurement points to the centers of different supports to output one-dimensional or two-dimensional compression displacement data and rotation angle data; Based on the obtained compression and rotation data, the two-dimensional displacement components of the measurement point relative to the reference point are calculated.
2. The finite element modeling method for a two-dimensional displacement sensor of a chest impactor or dummy according to claim 1, characterized in that, In the component geometry modeling and mesh generation steps: The slide rail sleeve is divided using quadrilateral shell units, with the mesh being densified in the flanged part and key stress areas of the sleeve. The support is modeled using hexahedral solid elements and uniformly meshed, with the mesh being fined in key stress areas and connection points.
3. The finite element modeling method for a two-dimensional displacement sensor of a chest impactor or dummy according to claim 1, characterized in that, The slide rail sleeve is made of an elastic-plastic material, and the support is made of a rigid material, including the following: The slide rail sleeve adopts the MAT3 elastoplastic material model, and the parameters of elastic modulus, yield strength and hardening modulus are set; The support adopts the MAT20 rigid material model.
4. The finite element modeling method for a two-dimensional displacement sensor of a chest impactor or dummy according to claim 1, characterized in that, During the connection setup process: Each node is connected sequentially by BEAM elements, and multiple BEAM elements are connected to the surface at both ends. BEAM_ORIENTATION elements are created by selecting nodes from the lower and upper end faces.
5. The finite element modeling method for a two-dimensional displacement sensor of a chest impactor or dummy according to claim 1, characterized in that, The hinge configuration includes: The two components at the rotating joint are connected using BEAM units made of material No.
66. Set the rotational stiffness of the BEAM element along the rotational direction of the revolute joint to zero, and assign translational or rotational stiffness to the remaining degrees of freedom; Use the CONSTRAINED_JOINT_STIFFNESS_GENERATION keyword to control the damping and limiting characteristics of the hinge.
6. The finite element modeling method for a two-dimensional displacement sensor of a chest impactor or dummy according to claim 1, characterized in that, The slide rail sleeve is equipped with self-contact technology to enable telescopic movement, including the following: Use CONTACT_AUTOMATIC_SINGLE_SURFACE to set self-contact for the slide rail sleeve; Use the CONSTRAINED_JOINT_STIFFNESS_TRANSLATION keyword to add a force-displacement curve between the components at both ends of the sensor.
7. The finite element modeling method for a two-dimensional displacement sensor of a chest impactor or dummy according to claim 1, characterized in that, In the output setup steps: One-dimensional measurement is achieved by establishing a low-stiffness DISCRETE element from the measurement point to the fixed support; Two-dimensional measurement is achieved by establishing a low-stiffness DISCRETE element from the measurement point to the rotatable support; Use the DATABASE_HISTORY_DISCRETE keyword to output the spring change.
8. The finite element modeling method for a two-dimensional displacement sensor of a chest impactor or dummy according to claim 1, characterized in that, The formula for calculating two-dimensional displacement components is as follows: in, This is the compression amount in the X direction. This is the compression amount in the Y direction. The angle is the rotation around the Z-axis.
9. The finite element modeling method for a two-dimensional displacement sensor of a chest impactor or dummy according to claim 8, characterized in that, The formula for calculating the relative displacement of the measurement point with respect to the reference point is as follows: 。 10. The finite element modeling method for a two-dimensional displacement sensor of a chest impactor or dummy according to claim 1, characterized in that, Also includes: The model was analyzed using an explicit dynamic solver to simulate the sensor's response during dynamic compression and to verify the model's validity.