A simulation method for dynamics performance of ice hockey leg guard based on finite element method

Abstract

The application discloses a simulation method for the dynamic performance of ice hockey leg guards based on a finite element method, and comprises the following steps: establishing an ice hockey leg guard model by a 3D scanning modeling device; importing the ice hockey leg guard model into finite element analysis software, and establishing a scene model based on the actual use scene of the ice hockey leg guard; setting material parameters and performing mesh division; coupling the scene model with the ice hockey leg guard model, setting the contact condition, the boundary condition and the analysis setting condition of the ice hockey leg guard, the ice hockey, the boundary wall and the ice hockey stick inside the ice hockey leg guard; based on the explicit dynamic analysis theory, combining simulation parameters under different working conditions, simulating the collision stress influence process of the leg guard when the ice hockey player collides with the leg in the competition, and obtaining a stress nephogram and a stress change curve; and judging the influence of different collision parameters on the ice hockey leg guard based on the stress nephogram and the stress change curve. The technical scheme of the application can obtain experimental results more in line with the actual situation, and improve the reliability of the simulation results.

Description

Technical Field

[0001] This invention relates to the field of simulation technology, and in particular to a simulation method for the dynamic performance of ice hockey shin guards based on the finite element method. Background Technology

[0002] Winter sports have a long history of development. In recent years, with the rapid popularization of winter sports, people's requirements for the performance of winter protective gear have been increasing. Traditional protective gear performance testing methods usually require the construction of specific test devices based on performance indicators. The entire test cycle is long, the economic cost is high, and it is easily affected by on-site equipment factors, making it difficult to obtain stable and accurate results. Simulation analysis technology has largely solved the shortcomings of traditional testing methods, but due to the different simulation objects, there are also many design problems, so further research and improvement are needed.

[0003] When hockey shin guards collide with an object, the relative velocity and angle between the two affect the stress distribution in the collision area. The main factor determining the performance of the shin guards is the material of the protective gear. Many experts have conducted research on the impact of impact on material properties.

[0004] One simulation method for CFRP laminates (Wang Jingdong, Pan Jingwen, Zhang Zhifang, et al. Experimental study on secondary low-velocity impact and residual compressive strength of CFRP laminates [J / OL]. Materials Reports, 2023(12):1-17.) uses the drop hammer method to conduct single and secondary low-velocity impacts on the same location of the CFRP laminate structure, thereby analyzing the effects of single and secondary impacts on the dynamic response, energy absorption, damage, and residual strength of the CFRP laminate. However, this method focuses more on the effect of the number of impacts on the CFRP laminate, without further analyzing the impact angle and velocity, and it relies on existing experimental equipment, which may lead to specimen damage. Simulation using the finite element method is currently a major research hotspot. A simulation method for composite laminates (Zhou J, Wen P, Wang S. Numerical investigation on the repeated low-velocity impact behavior of composite laminates[J]. Composites Part B: Engineering, 2020, 185: 107771.) was proposed. A finite element model of the laminate was established using ABAQUS / Explicit software. Based on this model, the overall mechanical response of the laminate under repeated impacts at different energies was analyzed using finite element methods. This method addresses the dependence on experimental equipment to some extent and is more efficient, avoiding damage to the specimens under repeated testing. However, this method focuses more on the influence of the number of impacts and does not consider the influence of impact velocity and angle. Furthermore, the model complexity is low and cannot simulate the collision situation of real objects. Another simulation method for quasi-isotropic carbon / epoxy resin tape laminates (Cui Q, Yang J. Evaluation of numerical simulation methods and ice material models for intermediate-velocity hail impact simulation[J]. Engineering Structures, 2021, 244: 112831.) analyzes the effect of high-speed impact on quasi-isotropic carbon / epoxy resin tape laminates using ANSYS / LS-DYNA software. Through impact experiments at two different impact angles and a wide velocity range, the influence of projectile kinetic energy on the laminate response is evaluated using residual velocity and damage area. This method considers the effects of impact velocity and angle and uses finite element analysis software for simulation analysis, offering advantages such as high efficiency and accuracy. However, the complexity of the established finite element model is relatively low, making it unable to reasonably simulate the actual usage of objects made of this material in real-world scenarios. Summary of the Invention

[0005] This invention provides a simulation method for the dynamic performance of hockey shin guards based on the finite element method. The aim is to offer a simulation method for the dynamic performance of hockey shin guards that is less labor-intensive, more efficient, and more closely reflects actual usage scenarios. This addresses the challenges of traditional material performance experiments, which require specific experimental setups, resulting in high economic costs throughout the testing cycle. Furthermore, the specimens suffer wear and tear with each test, making it difficult to obtain stable results. While simulation techniques are an improved approach, modeling specimens with complex surfaces is extremely labor-intensive, often resulting in shortcomings and focusing primarily on single-parameter simulations, making a comprehensive analysis of the specimen's dynamic performance difficult.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] A simulation method for the dynamic performance of hockey shin guards based on the finite element method includes:

[0008] A model of ice hockey shin guards was created using 3D scanning and modeling equipment;

[0009] The hockey shin guard model was imported into finite element analysis software, and a scene model was established based on the actual use scenario of the hockey shin guard; wherein, the scene model includes models of the hockey puck, the boundary wall, and the hockey stick;

[0010] Set the material parameters for each model and mesh each model;

[0011] Couple the scene model with the hockey shin guard model, and set the contact conditions, boundary conditions, and analysis settings for the inside of the hockey shin guard and the contact conditions between the hockey shin guard and the hockey puck, the boundary wall, and the hockey stick.

[0012] Based on explicit dynamic analysis theory and combined with simulation parameters under different working conditions, the impact stress of the leg guards during leg collisions of ice hockey players in competition is simulated, and stress cloud diagrams and stress change curves are obtained.

[0013] Based on the stress cloud diagram and stress change curve, the influence of different collision parameters on hockey leg guards is determined.

[0014] Furthermore, the process of establishing a hockey shin guard model using a 3D scanning and modeling device includes:

[0015] Real hockey shin guards are scanned and modeled using 3D scanning and modeling equipment to obtain a physical model;

[0016] The details in the solid model that do not affect the calculation accuracy are simplified, and some unnecessary structures are ignored and deleted to simplify the solid model and obtain the final hockey leg guard model.

[0017] Furthermore, the finite element analysis software is ANSYS Workbench software; the hockey shin guard model is imported into the finite element analysis software, and a scenario model is established based on the actual use scenario of the hockey shin guard, including:

[0018] Save the hockey shin guard model data file as a ".stp" file;

[0019] The LS-DYNA module in ANSYS Workbench software is selected, and the Geometry module in the LS-DYNA module is used to directly model the hockey puck, the boundary wall, and the hockey stick. The hockey puck is modeled at a 1:1 scale with the actual size, while the boundary wall and hockey stick are partially modeled to meet the simulation requirements.

[0020] Furthermore, setting the material parameters for each model and meshing each model includes:

[0021] Set the density, Young's modulus, Poisson's ratio, bulk modulus, and shear modulus of each model material;

[0022] Mesh the hockey shin guard model, hockey puck model, boundary wall model, and hockey stick model. For the hockey puck, boundary wall, and hockey stick, free meshing is used. For the collision area between the hockey shin guard and the hockey puck, boundary wall, and hockey stick, hexahedral meshing is used, and the mesh is refined to increase the mesh density. For the areas on the hockey shin guard that do not directly contact the hockey puck, boundary wall, and hockey stick, the mesh density is reduced.

[0023] Furthermore, when using hexahedral meshes to divide the collision area between the hockey shin guards and the hockey puck, the boundary wall, and the hockey stick, if meshing fails or the mesh quality is abnormal, free meshing should be used for areas where hexahedral meshing is difficult to use, and the mesh density of the corresponding areas should be increased.

[0024] Furthermore, the hockey shin guard model has a four-layer structure, namely a knee shell, a calf shell, an inner foam layer, and an outer foam layer;

[0025] The scene model is coupled with the hockey shin guard model, and the contact conditions, boundary conditions, and analysis settings for the hockey shin guard's interior, as well as its contact with the hockey puck, boundary walls, and hockey sticks, are set, including:

[0026] Constraints are set between the four layers of the hockey shin guard model to simulate the state of hockey shin guards in a real situation; wherein, the constraint type between every two layers of the hockey shin guard model is set to a binding constraint.

[0027] The constraints between the collision areas of the hockey puck, the boundary wall, and the hockey stick and the hockey leg guards are set to be frictional, with a coefficient of friction of 0.2. Based on the actual situation when hockey players wear hockey leg guards, the back area of ​​the inner foam layer of the hockey leg guards is selected as a fixed support to simulate the contact between the lower leg and the protective gear.

[0028] Couple the hockey, boundary wall, and hockey stick models with the hockey shin guard model. Place the hockey, boundary wall, and hockey stick models 0.1m outside the hockey shin guard model, set the end time to 0.02s, the initial substep to 10, the minimum substep to 10, and the maximum substep to 100. Set the calculation results in the output control to output at equidistant points and divide the output results into 100 nodes for display.

[0029] Furthermore, based on explicit dynamic analysis theory and combined with simulation parameters under different working conditions, the impact stress influence process of the leg guard during leg collisions in ice hockey is simulated, resulting in stress cloud diagrams and stress change curves, including:

[0030] Based on explicit dynamics theory, the dynamic equations for the collision of hockey leg guards are established:

[0031]

[0032] In the formula, M, C, K and Q(t) are the mass matrix, damping matrix, stiffness matrix and nodal load vector of the system, respectively; a(t) represents the acceleration vector, velocity vector, and displacement vector of the system nodes, respectively; where velocity and acceleration are represented by displacement, and their corresponding expressions are as follows:

[0033]

[0034]

[0035] In the formula, Δt is the time step;

[0036] Substituting equations (2) and (3) into equation (1), we obtain the recursive formula for solving each discrete time point:

[0037]

[0038] Based on the initial conditions of the given unit motion, the displacement at each discrete time point is solved by equation (4), and then the stress and strain of each unit are obtained; among them, three cases are selected with ice hockey speeds of 160km / h, 170km / h and 180km / h, and the impact angles of the ice hockey are selected as 90° and 45°; the simulation speed parameters of the boundary wall and ice hockey stick are set to 20km / h and 30km / h, and the impact angles are selected as 90° and 45°; the simulation of each working condition is carried out using the controlled variable simulation method using ANSYS software;

[0039] A program was written using Matlab software to plot the results of solving the dynamic equations using ANSYS software as stress variation curves of hockey gaiters under different working conditions and simulation parameters after the simulation was completed.

[0040] Furthermore, based on the stress cloud diagram and stress variation curve, the influence of different collision parameters on hockey shin guards is determined, including:

[0041] Analyze the stress cloud diagram and stress change curve to observe whether there are any abnormalities in the stress distribution. Based on the stress change curves of different parameters in the result diagram, determine the stress influence of the current parameters on the collision process.

[0042] In another aspect, the present invention also provides an electronic device comprising a processor and a memory; wherein the memory stores at least one instruction, which is loaded and executed by the processor to implement the above-described method.

[0043] In another aspect, the present invention also provides a computer-readable storage medium storing at least one instruction that is loaded and executed by a processor to implement the above-described method.

[0044] The beneficial effects of the technical solution provided by this invention include at least the following:

[0045] 1. This invention utilizes the advantages of 3D scanning in hockey shin guard modeling to establish an accurate hockey shin guard model. This avoids the inaccurate construction of complex curved surfaces of actual objects using modeling software, while greatly reducing the workload of modeling, saving time and costs, and improving experimental efficiency.

[0046] 2. Starting from the actual use scenario of hockey shin guards, this invention uses explicit dynamic simulation method combined with finite element analysis software to simulate the collision impact process between hockey shin guards and hockey pucks, walls and hockey sticks at multiple impact angles and multiple impact velocities. This can greatly improve the rationality of simulation results, avoid design defects, and further improve the accuracy and reliability of simulation results.

[0047] 3. This invention uses simulation to detect the stress effect process of hockey leg guards after impact, verifies the protective performance of hockey leg guards, reduces test costs, shortens the test cycle, and provides an effective method for verifying the protective performance of hockey leg guards. It is of great significance for further research on hockey leg guards in the future. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 This is a schematic diagram of the execution flow of the simulation method for the dynamic performance of ice hockey shin guards based on the finite element method provided in this embodiment of the invention;

[0050] Figure 2 This is a model diagram of ice hockey shin guards provided in an embodiment of the present invention; wherein, (a) is a front view of the model, (b) is a rear view of the model, (c) is a top view of the model, and (d) is a bottom view of the model;

[0051] Figure 3 This is a scene model diagram provided in an embodiment of the present invention; wherein, (a) is an ice hockey model, (b) is a boundary wall model, and (c) is an ice hockey stick model. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0053] First Embodiment

[0054] This embodiment provides a simulation method for the dynamic performance of hockey shin guards based on the finite element method, which can be implemented by electronic devices. This method obtains a precise model of the hockey shin guard through 3D scanning modeling, reducing the modeling workload while obtaining a more accurate model. Then, starting from the actual usage scenarios of the hockey shin guards, it simulates the impact process of collisions between the hockey shin guards and the hockey puck, boundary walls, and hockey sticks under multiple impact angles and velocities, thereby obtaining experimental results that more closely match reality and improving the reliability of the simulation results. Specifically, the execution flow of this method is as follows: Figure 1 As shown, it includes the following steps:

[0055] S1, A model of ice hockey shin guards is created using 3D scanning and modeling equipment;

[0056] It should be noted that the hockey shin guard modeled in this embodiment has a four-layer structure: a knee shell, a calf shell, an inner foam layer, and an outer foam layer. The modeling process is as follows: First, the real hockey shin guard is scanned and modeled using a 3D scanning modeling device. Given the complex structure of the real hockey shin guard, details such as seams, lace, and lining that do not significantly affect calculation accuracy are simplified. Unnecessary structures are ignored or deleted to improve the model's computational efficiency and reduce analysis time. The hockey shin guard model constructed in this embodiment is as follows: Figure 2 As shown. Of course, it is understood that this embodiment does not impose specific constraints on the selection of 3D scanning and modeling equipment and hockey shin guards.

[0057] S2, import the hockey shin guard model into the finite element analysis software, and establish a scene model based on the actual use scenario of the hockey shin guard; wherein, the scene model includes models of the hockey puck, the boundary wall, and the hockey stick;

[0058] It should be noted that the finite element analysis software used in S2 is ANSYS Workbench; of course, it is understood that it can also be achieved using other finite element analysis software, and this embodiment does not impose specific constraints.

[0059] The implementation process of S2 is as follows: the hockey shin guard model data file obtained in S1 is converted into a ".stp" file, which is a general three-dimensional model file. The LS-DYNA module in ANSYS Workbench software is selected, and the Geometry module in this module is used to directly model the hockey, boundary wall, and hockey stick. The hockey size is simulated and modeled at a 1:1 scale based on existing publicly available data. Since the boundary wall and hockey stick are relatively large compared to the hockey shin guard, partial modeling is chosen to meet the simulation requirements.

[0060] The scene model constructed in this embodiment is as follows: Figure 3 As shown.

[0061] S3, set the material parameters for each model and mesh each model;

[0062] Specifically, in this embodiment, the implementation process of S3 is as follows: The density, Young's modulus, Poisson's ratio, bulk modulus, and shear modulus of the material are set, and the selected material is one commonly used in this equipment. Then, the hockey shin guards, hockey puck, boundary wall, and hockey stick are meshed. For the hockey puck, boundary wall, and hockey stick, since their meshing has little impact on the final stress analysis of the hockey shin guards, free meshing is used to reduce computational load and increase computational efficiency. For the collision area between the hockey shin guards and the hockey puck, boundary wall, and hockey stick, a more effective hexahedral mesh is used, and the mesh is refined to increase the mesh density. For areas on the hockey shin guards that do not directly contact the hockey puck, boundary wall, and hockey stick, the mesh density is appropriately reduced.

[0063] It should be noted that when using hexahedral meshing for models with complex curved surfaces, such as hockey shin guards, limitations of the meshing method can easily lead to meshing failures or abnormal mesh quality. Therefore, when meshing failures or abnormal mesh quality occur, free meshing is used for areas where hexahedral meshing is difficult to perform. The mesh density in these areas is then increased to compensate for the meshing effect as much as possible, thereby improving the quality of the meshing in the collision region and optimizing the accuracy and efficiency of the calculations.

[0064] S4, Couple the scene model with the hockey leg guard model, and set the contact conditions, boundary conditions and analysis settings for the inside of the hockey leg guard and the contact conditions between the hockey leg guard and the hockey, the boundary wall and the hockey stick;

[0065] Specifically, in this embodiment, the implementation process of S4 is as follows:

[0066] Constraints were set between the four layers of the hockey shin guard in S1 to simulate the state of the hockey shin guard in a real-world scenario. The constraint type between every two layers was set to a binding constraint. The constraints between the collision areas of the hockey puck, the boundary wall, and the hockey stick with the hockey shin guard were set to frictional, with a friction coefficient of 0.2. Based on the actual situation when hockey players wear hockey shin guards, the back area of ​​the inner foam layer of the hockey shin guard was selected as a fixed support to reasonably simulate the contact between the lower leg and the protective gear. Then, the hockey puck, boundary wall, and hockey stick models were coupled with the simplified hockey shin guard model. Because the relative speeds of athletes with the puck, wall, and hockey sticks are very high in actual ice hockey games, in order to meet the requirement of a small response time at the moment of collision, the puck, wall, and hockey stick models are placed 0.1m outside the puck leg guard model, respectively. The end time is set to 0.02s, the initial substep is 10, the minimum substep is 10, and the maximum substep is 100. To facilitate the analysis of simulation results, the calculation results in the output control are set to output at equidistant points, and the output results are divided into 100 nodes for display to ensure that enough data is collected for subsequent analysis.

[0067] S5, based on explicit dynamic analysis theory and combined with simulation parameters under different working conditions, simulates the impact stress of leg guards on ice hockey players during leg collisions, and obtains stress cloud diagrams and stress change curves.

[0068] Specifically, in this embodiment, the implementation process of S5 is as follows:

[0069] Based on explicit dynamics theory, the dynamic equations for the collision of hockey leg guards are established:

[0070]

[0071] In the formula, M, C, K and Q(t) are the mass matrix, damping matrix, stiffness matrix and nodal load vector of the system, respectively; a(t) represents the acceleration vector, velocity vector, and displacement vector of the system nodes, respectively. ANSYS / LS-DYNA primarily uses the central difference scheme in the direct integration method to solve the above dynamic equations, where velocity and acceleration are represented by displacement, and the corresponding expressions are as follows:

[0072]

[0073]

[0074] In the formula, Δt is the time step;

[0075] Substituting equations (2) and (3) into equation (1), we obtain the recursive formula for solving each discrete time point:

[0076]

[0077] Based on the initial conditions of the given unit motion, the displacement at each discrete time point can be solved by equation (4), and then the stress and strain of each unit can be obtained.

[0078] Specifically, for the set working conditions, based on existing ice hockey data, the speed of the puck can generally reach 160-180 km / h. Therefore, three scenarios with puck speeds of 160 km / h, 170 km / h, and 180 km / h were selected. The impact angles of the puck were considered for both vertical and oblique shots, with 90° (vertical) and 45° (oblique upward) angles chosen. The simulation speed parameters for the boundary wall and puck sticks were referenced from the speeds of top ice hockey players, both set to 20 km / h and 30 km / h, respectively, with the same impact angles as the puck (90° (vertical) and 45° (oblique upward)). In the ANSYS software settings, the km / h unit was uniformly converted to mm / s, and the unit system in the solver settings was changed to mm.ms.kg to match the input parameters after unit conversion. The ANSYS software was then used to further simulate each working condition using a controlled variable simulation method. A program was written using Matlab software to combine the results of solving the dynamic equations in ANSYS software (in ".txt" format) with the Matlab program to output the stress variation curves of hockey gaiters under different working conditions and simulation parameters.

[0079] It should be noted that Matlab is an internationally standard simulation software. Using Matlab to plot the solutions (stress change values) of the dynamic equations obtained by ANSYS software is completely effective and feasible, and can intuitively represent stress changes.

[0080] S6. Based on the stress cloud diagram and stress change curve, determine the impact of different collision parameters on hockey leg guards.

[0081] Specifically, in this embodiment, S6 is as follows: analyze the stress cloud map and the stress change curve, observe whether there are any abnormalities in the stress distribution, and determine the stress influence of the current parameter on the collision process based on the stress change curves of different parameters in the result map, so as to provide a reference for optimizing the design of hockey leg guards.

[0082] In summary, the method in this embodiment utilizes 3D scanning and modeling equipment to construct a simulation model of the hockey shin guard, solving the problems associated with traditional methods using 3D modeling software. This significantly reduces the modeling workload and improves experimental efficiency. Furthermore, thanks to the precision of 3D scanning, the constructed model has a higher degree of fit to the physical model, better reflecting its characteristics and improving the accuracy and reliability of subsequent simulation results. Moreover, by setting the collision object of the hockey shin guard in conjunction with its actual usage environment, and considering the influence of the relative velocity and impact angle of the collision object on the collision process, this method analyzes the performance of the hockey shin guard in collisions from a holistic structural perspective using a more realistic simulation strategy. This addresses potential design flaws in traditional simulation methods, resulting in more convincing simulation results.

[0083] Second Embodiment

[0084] This embodiment provides an electronic device, which includes a processor and a memory; wherein the memory stores at least one instruction, which is loaded and executed by the processor to implement the method of the first embodiment.

[0085] The electronic device can vary considerably depending on its configuration or performance, and may include one or more processors (central processing units, CPUs) and one or more memories, wherein the memories store at least one instruction that is loaded by the processor and executed in accordance with the above method.

[0086] Third Embodiment

[0087] This embodiment provides a computer-readable storage medium storing at least one instruction, which is loaded and executed by a processor to implement the method of the first embodiment described above. The computer-readable storage medium may be a ROM, random access memory, CD-ROM, magnetic tape, floppy disk, or optical data storage device, etc. The instruction stored therein can be loaded and executed by a processor in a terminal.

[0088] Furthermore, it should be noted that the present invention can be provided as a method, apparatus, or computer program product. Therefore, embodiments of the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, embodiments of the present invention can take the form of a computer program product implemented on one or more computer-usable storage media containing computer-usable program code.

[0089] Embodiments of the present invention are described with reference to flowchart illustrations and / or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, embedded processor, or other programmable data processing terminal device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal device, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0090] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing terminal device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The functions specified in one or more boxes. These computer program instructions may also be loaded onto a computer or other programmable data processing terminal equipment to cause a series of operational steps to be performed on the computer or other programmable terminal equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable terminal equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0091] It should also be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0092] Finally, it should be noted that the above description represents a preferred embodiment of the present invention. It should be pointed out that although preferred embodiments have been described, those skilled in the art, once they understand the basic inventive concept of the present invention, can make various improvements and modifications without departing from the principles described herein. These improvements and modifications should also be considered within the scope of protection of the present invention. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present invention.

Claims

1. A simulation method of the dynamics performance of a hockey leg guard based on the finite element method, characterized in that, The simulation method for the dynamic performance of ice hockey shin guards based on the finite element method includes: A model of ice hockey shin guards was created using 3D scanning and modeling equipment; The hockey shin guard model was imported into finite element analysis software, and a scene model was established based on the actual use scenario of the hockey shin guard; wherein, the scene model includes models of the hockey puck, the boundary wall, and the hockey stick; Set the material parameters for each model and mesh each model; Couple the scene model with the hockey shin guard model, and set the contact conditions, boundary conditions, and analysis settings for the inside of the hockey shin guard and the contact conditions between the hockey shin guard and the hockey puck, the boundary wall, and the hockey stick. Based on explicit dynamic analysis theory and combined with simulation parameters under different working conditions, the impact stress of the leg guards during leg collisions of ice hockey players in competition is simulated, and stress cloud diagrams and stress change curves are obtained. Based on the stress cloud diagram and stress change curve, the influence of different collision parameters on hockey shin guards is determined. Based on explicit dynamic analysis theory and combined with simulation parameters under different working conditions, the impact stress effect of leg guards on ice hockey players during leg collisions is simulated, resulting in stress cloud diagrams and stress change curves, including: Based on explicit dynamics theory, the dynamic equations for the collision of hockey leg guards are established: （1）； In the formula, , , and These are the system's mass matrix, damping matrix, stiffness matrix, and nodal load vector, respectively. , , These are the acceleration vector, velocity vector, and displacement vector of the system nodes, respectively; where velocity and acceleration are represented by displacement, and their corresponding expressions are as follows: （2）； （3）； In the formula, For time step; Substituting equations (2) and (3) into equation (1), we obtain the recursive formula for solving each discrete time point: （4）； Based on the initial conditions of the given unit motion, the displacement at each discrete time point is solved by equation (4), and then the stress and strain of each unit are obtained; among them, three cases are selected with ice hockey speeds of 160km / h, 170km / h and 180km / h, and the impact angles of the ice hockey are selected as 90° and 45°; the simulation speed parameters of the boundary wall and ice hockey stick are set to 20km / h and 30km / h, and the impact angles are selected as 90° and 45°; the simulation of each working condition is carried out using the controlled variable simulation method using ANSYS software; A program was written using Matlab software to plot the results of solving the dynamic equations using ANSYS software as stress variation curves of hockey gaiters under different working conditions and simulation parameters after the simulation was completed.

2. The simulation method for the dynamic performance of ice hockey shin guards based on the finite element method as described in claim 1, characterized in that, The process of creating a hockey hockey shin guard model using 3D scanning and modeling equipment includes: Real hockey shin guards are scanned and modeled using 3D scanning and modeling equipment to obtain a physical model; The details in the solid model that do not affect the calculation accuracy are simplified, and some unnecessary structures are ignored and deleted to simplify the solid model and obtain the final hockey leg guard model.

3. The simulation method for the dynamic performance of ice hockey shin guards based on the finite element method as described in claim 1, characterized in that, The finite element analysis software is ANSYS Workbench. The hockey shin guard model was imported into finite element analysis software. Based on the actual usage scenarios of the hockey shin guards, a scenario model was established, including: Save the hockey shin guard model data file as a ".stp" file; The LS-DYNA module in ANSYS Workbench software is selected, and the Geometry module in the LS-DYNA module is used to directly model the hockey puck, the boundary wall, and the hockey stick. The hockey puck is modeled at a 1:1 scale with the actual size, while the boundary wall and hockey stick are partially modeled to meet the simulation requirements.

4. The simulation method for the dynamic performance of ice hockey shin guards based on the finite element method as described in claim 1, characterized in that, The process of setting the material parameters for each model and meshing each model includes: Set the density, Young's modulus, Poisson's ratio, bulk modulus, and shear modulus of each model material; Mesh the hockey shin guard model, hockey puck model, boundary wall model, and hockey stick model. For the hockey puck, boundary wall, and hockey stick, free meshing is used. For the collision area between the hockey shin guard and the hockey puck, boundary wall, and hockey stick, hexahedral meshing is used, and the mesh is refined to increase the mesh density. For the areas on the hockey shin guard that do not directly contact the hockey puck, boundary wall, and hockey stick, the mesh density is reduced.

5. The simulation method for the dynamic performance of ice hockey shin guards based on the finite element method as described in claim 4, characterized in that, When using hexahedral meshes to divide the collision area between the hockey shin guards and the hockey puck, the boundary wall, and the hockey stick, if meshing fails or the mesh quality is abnormal, free meshing should be used for areas where hexahedral meshing is difficult to use, and the mesh density of the corresponding areas should be increased.

6. The simulation method for the dynamic performance of ice hockey shin guards based on the finite element method as described in claim 1, characterized in that, The hockey shin guard model has a four-layer structure, namely a knee shell, a calf shell, an inner foam layer, and an outer foam layer; The scene model is coupled with the hockey shin guard model, and the contact conditions, boundary conditions, and analysis settings for the hockey shin guard's interior, as well as its contact with the hockey puck, boundary walls, and hockey sticks, are set, including: Constraints are set between the four layers of the hockey shin guard model to simulate the state of hockey shin guards in a real situation; wherein, the constraint type between every two layers of the hockey shin guard model is set to a binding constraint. The constraints between the collision areas of the hockey puck, the boundary wall, and the hockey stick and the hockey leg guards are set to be frictional, with a coefficient of friction of 0.

2. Based on the actual situation when hockey players wear hockey leg guards, the back area of ​​the inner foam layer of the hockey leg guards is selected as a fixed support to simulate the contact between the lower leg and the protective gear. Couple the hockey, boundary wall, and hockey stick models with the hockey shin guard model. Place the hockey, boundary wall, and hockey stick models 0.1m outside the hockey shin guard model, set the end time to 0.02s, the initial substep to 10, the minimum substep to 10, and the maximum substep to 100. Set the calculation results in the output control to output at equidistant points and divide the output results into 100 nodes for display.

7. The simulation method for the dynamic performance of ice hockey shin guards based on the finite element method as described in claim 1, characterized in that, Based on the stress cloud map and stress change curve, the influence of different collision parameters on hockey shin guards is determined, including: Analyze the stress cloud diagram and stress change curve to observe whether there are any abnormalities in the stress distribution. Based on the stress change curves of different parameters in the result diagram, determine the stress influence of the current parameters on the collision process.

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