Multi-physics finite element modeling method, system and storage medium for honeycomb structure

Abstract

The application provides a multi-physical field finite element modeling method and system of a honeycomb structure and a storage medium, and relates to the technical field of finite element modeling of a honeycomb structure. In the prior art, when finite element modeling is performed on a honeycomb structure, the calculation efficiency and simulation accuracy cannot be considered at the same time, and it is difficult to simultaneously reproduce the internal air heat insulation compression effect and the in-plane shear tearing effect. The application builds a macro-homogeneous solid-failed beam element network-enclosed air bag three-integrated model, and establishes a dynamic coupling mechanism, so that the real-time failure state of the beam element directly controls the air bag leakage hole area, realizes physical driving type high-fidelity simulation of the dynamic air effect and local tearing effect of the honeycomb material, improves the precision of collision load prediction and energy absorption evaluation, and through multi-working condition test data system calibration, the robustness and generalization ability of the model in a complex impact scene are enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of finite element modeling of honeycomb structure, and particularly relates to a multi-physical field finite element modeling method and system of honeycomb structure and a storage medium. BACKGROUND

[0002] Honeycomb structure, especially aluminum honeycomb material, has been widely used in deformable barrier in vehicle crash test due to its excellent specific strength, high energy absorption efficiency and controllable deformation mode. It can dissipate the kinetic energy of the collision by ordered plastic buckling, and can truly simulate the collision interaction between the vehicle and the deformable object, thereby providing key experimental basis for evaluating the safety performance of the vehicle. With the continuous improvement of automobile safety standards and the promotion of lightweight design, higher requirements are put forward for the precision and efficiency of crash simulation prediction. Developing high-fidelity and high-computing-efficiency finite element model of honeycomb structure has important engineering value and broad application prospect for accelerating the positive development of vehicle safety performance and reducing research and development cost.

[0003] However, the existing finite element modeling method of honeycomb structure faces significant challenges in precision and efficiency, and cannot meet the needs of engineering practice. The adiabatic effect of the closed air inside the honeycomb cell during dynamic compression is ignored, and the dynamic stress enhancement phenomenon caused thereby cannot be simulated. Secondly, the existing homogenization model cannot characterize and predict the local tearing failure mode of the honeycomb under in-plane shear load and its influence on the overall force and displacement response. Finally, the parameters of such model are heavily dependent on the geometric configuration of a specific honeycomb, and once the geometric size changes, a large number of physical tests need to be performed to calibrate the parameters, resulting in insufficient generalization ability.

[0004] Therefore, the existing technology lacks a multi-physical field finite element modeling method of honeycomb structure with higher simulation precision and generalization ability. SUMMARY

[0005] To this end, the present application provides a multi-physical field finite element modeling method, system and storage medium of honeycomb structure to overcome the problems that the existing technology cannot simulate the dynamic stress enhancement phenomenon caused by the adiabatic effect of the closed air inside the honeycomb cell during dynamic compression, cannot describe and predict the discrete in-plane shear tearing failure, and has weak model generalization ability.

[0006] To achieve the above-mentioned purpose, the present application provides a multi-physical field finite element modeling method of honeycomb structure, comprising:

[0007] S1, establishing a solid finite element model according to the geometric size of the honeycomb barrier, and performing mesh division on the solid finite element model;

[0008] S2, calibrating the structure parameters of the solid finite element model based on the quasi-static uniform compression test data of the honeycomb material;

[0009] S3, introducing physical gaps to regularly divide the continuous solid mesh in-plane, and using discrete beam elements to connect corresponding nodes on both sides of the physical gaps to generate a beam element network;

[0010] S4, constructing a closed cavity inside the beam element network based on the ideal gas state equation, and calibrating the functional relationship between the area of the leakage hole in the closed cavity and the pressure borne by the beam element network using dynamic uniform compression test data of the cellular material;

[0011] S5, establishing a dynamic coupling mechanism for dynamically adjusting the area of the leakage hole in the closed cavity according to the real-time failure state of the beam elements in the beam element network during simulation.

[0012] Further, the elongation of the beam element has three calculation methods based on the pressure borne, including:

[0013] linear elastic segment, if the pressure borne by the beam element is less than or equal to a first threshold value, the elongation of the beam element is in a positive proportional relationship with the pressure borne;

[0014] plastic platform segment, if the pressure borne by the beam element is greater than the first threshold value and less than or equal to a second threshold value, the elongation of the beam element is a constant value;

[0015] failure segment, if the pressure borne by the beam element is greater than the second threshold value, the elongation of the beam element is a preset maximum value for simulating the failure process of the beam element.

[0016] Further, the calibration of the structural parameters of the solid finite element model based on the quasi-static uniform compression test data of the cellular material includes:

[0017] S21, preparing a standard specimen of cellular material and performing a quasi-static uniform compression test on a universal testing machine;

[0018] S22, recording the force applied and the displacement generated during the test, and calculating and generating an engineering stress-displacement curve, and extracting key mechanical characteristic parameters, mainly including initial elastic modulus, yield stress, platform stress, and densification strain;

[0019] S23, establishing a simulation model that is completely consistent with the geometric size, constraint, and loading conditions of the standard specimen, and performing the same mesh division as S1;

[0020] S24, assigning an anisotropic elastoplastic constitutive model to the solid elements in the simulation model;

[0021] S25 uses the engineering stress-displacement curve obtained in S22 as the target benchmark, takes the platform stress as the core calibration target, and performs simulation by repeatedly adjusting the input parameters in the constitutive model to generate simulation curves;

[0022] S26. When the platform stress value of the simulation curve matches the platform stress measured in S22, and the overall shape of the simulation curve is highly consistent with the engineering stress-displacement curve, the calibration is considered complete.

[0023] Furthermore, the calibration of the functional relationship between the area of ​​the leakage holes in the closed cavity and the pressure on the beam element network using dynamic uniform compression test data of the honeycomb material includes:

[0024] S41, a standard sample of the honeycomb material is prepared and subjected to a dynamic uniform compression test. The sample is impacted with a preset strain rate to simulate the loading conditions during the collision process. The dynamic force and displacement data during the impact process are recorded to generate a dynamic force-displacement curve.

[0025] S42, compare the dynamic force-displacement curve with the engineering stress-displacement curve of the same honeycomb material;

[0026] S43, calculate the difference between the dynamic force value and the engineering stress value at the same displacement point, and define the curve formed by the difference sequence as the experimental dynamic overstress curve;

[0027] S44, On the boundary of the closed cavity, establish a functional relationship between the area of ​​the leakage hole and the pressure on the beam element network;

[0028] S45, set the same boundary conditions and impact velocity as the dynamic uniform compression test, and perform dynamic uniform compression simulation;

[0029] S46, Based on the results of dynamic uniform compression simulation, determine the undetermined parameters in the functional relationship between the area of ​​the leakage hole and the pressure on the beam element network.

[0030] Furthermore, the undetermined parameters for determining the functional relationship between the area of ​​the leakage hole and the pressure on the beam element network based on the results of dynamic uniform compression simulation include:

[0031] S461, Establish a curve consisting of the difference sequence between the dynamic force-displacement curve obtained from dynamic uniform compression simulation and the dynamic force-displacement curve obtained from dynamic uniform compression test, as the simulated dynamic overstress curve.

[0032] S462, Based on the difference between the simulated dynamic overstress curve and the experimental dynamic overstress curve, adjust the undetermined parameter in the functional relationship between the area of ​​the leakage hole and the pressure on the beam element network;

[0033] S463, If the difference between the simulated dynamic overstress curve and the experimental dynamic overstress curve is greater than the preset overstress threshold, then return to S45 and repeat the dynamic uniform compression simulation.

[0034] If the difference between the simulated dynamic overstress curve and the experimental dynamic overstress curve is less than or equal to the preset overstress threshold, the calibration is determined to be complete, and the functional relationship between the area of ​​the leakage hole in the closed cavity and the pressure on the beam element network is output.

[0035] Furthermore, the step of dynamically adjusting the area of ​​the leakage holes in the closed cavity based on the real-time failure status of the beam elements in the beam element network includes:

[0036] S51, During the collision simulation calculation, the elongation of each beam element in the beam element network is monitored and recorded in real time;

[0037] S52, compare the elongation of each beam element monitored in real time with the second threshold. If the elongation of a beam element is found to be greater than the second threshold, it is determined to be a failed beam element.

[0038] S53, based on the spatial position of the failed beam element in the model, map and locate the corresponding region on the shell element wall of the closed cavity;

[0039] S54, according to the preset coupling rules, calculate the area of ​​additional leakage holes that should be activated or increased in the region corresponding to the failed beam element;

[0040] S55, repeat S51 until the collision simulation calculation process ends.

[0041] Furthermore, the leakage holes in the closed cavity are used to simulate the real coupling failure process during the collision, where the honeycomb wall is sheared and torn, resulting in macroscopic tears that cause the high-pressure gas inside to escape from the macroscopic tears at an accelerated rate.

[0042] The present invention also provides a multiphysics finite element modeling system for honeycomb structures, the system being used to implement any of the multiphysics finite element modeling methods for honeycomb structures described above, the system comprising:

[0043] The mesh generation module is used to establish a solid finite element model based on the geometric dimensions of the cellular barrier, and to mesh the solid finite element model.

[0044] The constitutive parameter calibration module is connected to the mesh generation module and is used to calibrate the structural parameters of the solid finite element model based on quasi-static uniform compression test data of honeycomb materials.

[0045] The network embedding module, connected to the constitutive parameter calibration module, is used to introduce physical gaps to regularly divide the continuous solid mesh in the plane, and to use discrete beam elements to connect the corresponding nodes on both sides of the physical gaps to generate a beam element network.

[0046] An air effect calibration module, connected to the network embedding module, is used to construct a closed cavity inside the beam element network based on the ideal gas law, and to calibrate the functional relationship between the area of ​​the leakage holes in the closed cavity and the pressure on the beam element network using dynamic uniform compression test data of the honeycomb material.

[0047] The dynamic coupling execution module, connected to the air effect calibration module, is used to establish a dynamic coupling mechanism to dynamically adjust the area of ​​the leakage holes in the closed cavity according to the real-time failure state of the beam elements in the beam element network during the simulation process.

[0048] The present invention also provides a computer-readable storage medium storing instructions that, when executed on a terminal device, cause the terminal device to perform any of the multiphysics finite element modeling methods for cellular structures described in the present invention.

[0049] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0050] Firstly, this invention, by integrating and calibrating a built-in closed cavity model, accurately quantifies the adiabatic compression effect of internal air within a highly efficient homogenized framework for the first time. This significantly improves the simulation accuracy under dynamic load conditions. Traditional macroscopic homogenized models completely ignore the physical existence of closed air within the honeycomb cells, leading to an inability to reproduce the dynamic overstress phenomenon caused by rapid air compression during high-speed collisions in simulations, resulting in significantly lower predicted peak collision forces. This invention innovatively constructs a closed cavity within a solid skeleton that follows the ideal gas law. Based on a systematic comparison of dynamic and quasi-static compression test data, it decouples and extracts the contribution of pure air effects. Through iterative calibration, it determines the functional relationship describing the leakage hole area and the internal cavity pressure, fundamentally solving the systematic prediction bias caused by ignoring key physical fields.

[0051] Secondly, this invention establishes a dynamic coupling mechanism between mechanical tearing and gas leakage, achieving a physically driven high-fidelity simulation of the gas escape process. This further improves the accuracy of transient response and energy absorption prediction. Existing technologies, even considering air effects, often employ a fixed leakage mode, failing to simulate the dynamic coupling process of leakage caused by structural damage. This invention creatively establishes an event-based real-time coupling interface, continuously monitoring the beam element network representing in-plane connection strength during simulation. When its elongation exceeds the failure threshold, an action is immediately triggered, dynamically activating or enlarging an additional leakage hole on the airbag wall corresponding to the tear location. The area of ​​the leakage hole is correlated with the degree of failure of the beam element, simulating the true causal chain of high-pressure gas escape caused by the formation of leakage channels due to cell wall tearing. This allows the model to not only simulate the loading effect of air compression but also accurately simulate the pressure decay caused by leakage and its impact on the overall force-displacement curve, thereby achieving a more refined and physically consistent prediction of the timing and total amount of energy absorption during the collision process.

[0052] Thirdly, this invention significantly enhances the model's robustness and generalization ability in complex, non-uniform collision scenarios through a multi-physics integrated architecture and systematic calibration process, encompassing a macroscopic skeleton, a microscopic failure network, and an internal fluid cavity. It integrates three core physical fields—macroscopic compression, in-plane shear tearing, and internal aerodynamics—into a unified model in a modular manner and performs systematic, step-by-step calibration using multi-condition test data. Dynamic coupling enables real-time interaction between the physical fields according to the simulation progress, resulting in excellent stability and predictive reliability when simulating complex engineering scenarios such as column impacts and corner impacts that induce asymmetric deformation and localized failures. Furthermore, since the core parameters are derived from physical test calibration, it reduces repetitive work required for fine-tuning product specifications, improving the efficiency and robustness of engineering applications. Attached Figure Description

[0053] Figure 1 A flowchart illustrating the multiphysics finite element modeling method for honeycomb structures provided in this embodiment of the invention;

[0054] Figure 2 The structural block diagram of the multiphysics finite element modeling system for honeycomb structures provided in the embodiments of the present invention is shown. Detailed Implementation

[0055] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0056] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0057] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0058] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0059] Example

[0060] like Figure 1 As shown, the present invention provides a multiphysics finite element modeling method for honeycomb structures, characterized by comprising:

[0061] S1. Establish a solid finite element model based on the geometric dimensions of the cellular barrier, and mesh the solid finite element model.

[0062] S2, calibrating the structural parameters of the solid finite element model based on quasi-static uniform compression test data of honeycomb materials, including:

[0063] S21, Prepare a standard sample of the honeycomb material and perform a quasi-static uniform compression test on a universal testing machine;

[0064] S22 records the applied force and displacement during the test, calculates and generates the engineering stress-displacement curve, and extracts key mechanical characteristic parameters, mainly including initial elastic modulus, yield stress, plateau stress and compaction strain.

[0065] S23, Establish a simulation model that is completely consistent with the geometric dimensions, constraints and loading conditions of the standard specimen, and perform the same mesh generation as in S1;

[0066] S24, assigns an anisotropic elastoplastic constitutive model to the solid elements in the simulation model;

[0067] S25 uses the engineering stress-displacement curve obtained in S22 as the target benchmark, takes the platform stress as the core calibration target, and performs simulation by repeatedly adjusting the input parameters in the constitutive model to generate simulation curves;

[0068] S26. When the platform stress value of the simulation curve matches the platform stress measured in S22, and the overall shape of the simulation curve is highly consistent with the engineering stress-displacement curve, the calibration is considered complete.

[0069] In one possible implementation, the aluminum honeycomb core material commonly used in moving progressive deformable barriers in automobile crash tests is taken as the modeling object. The material is aluminum honeycomb, the side length of the regular hexagonal cell is 9.55mm, the corresponding cell size is 19.1mm, the aluminum foil thickness is 0.076mm, and the theoretical density of the core material is 28.6 kg / m³. A representative volume element for calibration is established, and the geometry is set as a cube with a side length of 200mm.

[0070] A cubic honeycomb specimen with dimensions identical to the target model was used. To ensure uniform loading, the upper and lower surfaces of the specimen were firmly bonded to a 20mm thick rigid steel plate using high-strength epoxy resin, forming a stable loading interface. A displacement-controlled quasi-static compression test was conducted on an electronic universal testing machine at a loading rate of 2mm / min. The load and displacement applied by the machine's indenter were continuously and synchronously recorded until the specimen was completely compressed to a dense state. The collected raw load and displacement data were converted into engineering stress-displacement curves based on the initial bearing area of ​​the specimen. The following key mechanical characteristic parameters were extracted from the stress-strain curves as calibration targets for subsequent simulations:

[0071] The initial elastic modulus is the slope of the initial linear segment of the curve, which is approximately 12.5 MPa in this example.

[0072] Platform stress, the average stress value in the relatively stable region of stress fluctuation in the curve, is the most critical indicator characterizing the energy absorption capacity of a cellular network. In this example, the measured value is approximately 0.32 MPa.

[0073] The initial densification strain is the strain point at which stress begins to rise sharply, marking the point at which the honeycomb structure is completely crushed. In this example, the observed value is approximately 0.78.

[0074] Based on experimental data, a corresponding simulation model was constructed in finite element software. Preferably, in LS-DYNA software, a 200mm cube geometry identical in size to the physical specimen was created, and hexahedral-dominated solid elements were used for meshing. To balance computational efficiency and deformation capture accuracy, the global element feature size was set to 10mm. To balance computational efficiency and stability, hexahedral solid elements with single-point integration were selected, employing a viscous hourglass control formula with coefficients set through preliminary testing to suppress potential zero-energy deformation modes. A local material coordinate system was established in the model to ensure strict alignment with the macroscopic anisotropic principal axes of the honeycomb structure.

[0075] The T-direction, or thickness direction, is perpendicular to the honeycomb core panel and is the main load-bearing and compression direction.

[0076] The L direction, i.e., longitudinal, is the direction of extension parallel to the cell wall of the honeycomb.

[0077] The W direction, i.e., the horizontal direction, is perpendicular to the L direction within the honeycomb plane.

[0078] A material model capable of characterizing the orthogonal anisotropy and compressible elastoplastic behavior of the honeycomb material is selected. In this embodiment, the MaterialType 126 model in LS-DYNA is preferred. The stress-strain curve in the T direction obtained from the experiment is discretized into multiple data points, which serve as the initial input curve for the compressive response in the T direction of the MaterialType 126 model. The elastic modulus and yield stress in the L and W directions are initially estimated based on the typical anisotropy ratio of the honeycomb material.

[0079] Boundary conditions consistent with physical experiments were set, and an explicit solver was used, but the kinetic energy ratio was strictly controlled to simulate a quasi-static process. Compression simulation was run, and the stress-strain curves output from the simulation were extracted and compared with the experimental curves. The plateau stress value of the simulation curve was stabilized around 0.32 MPa. Through multiple iterations, key parameters in the Material Type 126 input curve were finely adjusted, mainly including the elastic modulus in the T direction, yield stress, slope of the hardening segment, and the setting of the compaction strain point. When the simulation curve formed a stable plateau around 0.32 MPa, the average stress value in the plateau region had an error of less than 5% compared with the experimental value, and the initial compaction strain was consistent with the experimental observation, and the overall curve shape highly matched, the S1 calibration was deemed complete, and a set of calibrated key material parameters were determined. For example, the elastic modulus in the T direction was 12.8 MPa, and the compressive yield stress in the T direction was 0.315 MPa.

[0080] This invention uses the overall outer envelope geometry of the cellular barrier to perform solid mesh generation. It then systematically iteratively calibrates the model parameters using quasi-static uniform compression test data. This ensures that the overall force-displacement response of the model under the most basic and critical quasi-static compressive load is highly consistent with the physical test results. This provides an accurate and reliable macroscopic mechanical background and deformation skeleton for introducing more complex local failures and dynamic effects, thus improving model accuracy. By employing a hexahedral-dominated solid element mesh, combined with single-point integration and a controllable hourglass suppression algorithm, the risk of numerical failures such as negative volume and hourglass mode runaway in large-scale collision deformation simulations is reduced, improving the success rate and reliability of the entire simulation process. Furthermore, by adopting a macroscopic homogenization modeling approach, the number of elements in the model is reduced by one to two orders of magnitude, making large-scale, iterative collision simulations of vehicle systems containing such cellular barriers possible, fundamentally improving the efficiency of engineering design.

[0081] S3 introduces physical gaps to regularly divide the continuous solid mesh in the plane, and uses discrete beam elements to connect the corresponding nodes on both sides of the physical gaps to generate a beam element network.

[0082] The elongation of the beam element is calculated based on the applied pressure in three ways, including:

[0083] In the linear elastic segment, if the pressure on the beam element is less than or equal to the first threshold, the elongation of the beam element is directly proportional to the pressure.

[0084] In the plastic platform segment, if the pressure on the beam element is greater than the first threshold and less than or equal to the second threshold, the elongation of the beam element is a constant value.

[0085] In the failure stage, if the pressure on the beam element is greater than the second threshold, the elongation of the beam element is a preset maximum value, which is used to simulate the failure process of the beam element.

[0086] In one possible implementation, a hexahedral mesh region with a side length of 200 mm is used as input, with a global cell size of 10 mm, consisting of 8000 hexahedral cells. All cells are continuously connected in the plane. Based on the requirements of the invention effect and numerical stability, the width of the physical gap is set to 1.0 mm in this embodiment.

[0087] Without altering the element shape, a small, element-free blank area—a physical gap—is created between adjacent solid elements by severing the shared node connections in the in-plane direction. Specifically, for each pair of adjacent elements in the XY plane, the system locates their previously shared common node. A node separation command is executed, copying the common node into two overlapping independent nodes, which are then assigned to the two adjacent elements. At this point, the two elements no longer share a common node connection in the in-plane direction. One set of newly generated nodes is translated 0.5 mm along the normal direction of its plane, and the other set is translated 0.5 mm in the opposite direction, creating a physical gap with a total width of 1.0 mm between the two sets of nodes. The original continuous solid mesh is thus regularly cut apart in the in-plane.

[0088] Discrete mechanical connection elements, namely beam elements, are used to reconnect the corresponding nodes separated by gaps, simulating the potential connection strength between cell walls in a honeycomb structure. For each pair of nearest neighbors on both sides of a gap, which should have been connected, a node pair is defined. A new set of elements is created in the finite element model, with discrete beam elements selected as the element type. All identified node pairs are traversed, and discrete beam elements are created one by one, using the two nodes in each pair as the start and end points of the beam element. Finally, a two-dimensional beam element network that completely corresponds to the topology of the solid mesh and covers the entire plane of the model is formed. This network is located between the solid elements and embedded in a 1.0 mm physical gap.

[0089] This invention solves the technical challenge of quantifying and independently calibrating local tearing behavior by employing discrete beam elements as controllable failure proxies. It achieves parameterized and modular characterization of the physical process of shear tearing, improving the controllability and prediction accuracy of the model. By maintaining the macroscopic mesh unchanged and embedding only lightweight connection networks, it perfectly resolves the sharp contradiction between computational efficiency and model complexity while introducing key failure mechanisms. It endows the efficient macroscopic model with the key ability to accurately simulate local failures with minimal computational overhead.

[0090] S4. Based on the ideal gas law, a closed cavity is constructed inside the beam element network, and the functional relationship between the area of ​​the leakage hole in the closed cavity and the pressure on the beam element network is calibrated using dynamic uniform compression test data of honeycomb material.

[0091] The calibration of the functional relationship between the area of ​​the leakage holes in the closed cavity and the pressure on the beam element network using dynamic uniform compression test data of honeycomb materials includes:

[0092] S41, a standard sample of the honeycomb material is prepared and subjected to a dynamic uniform compression test. The sample is impacted with a preset strain rate to simulate the loading conditions during the collision process. The dynamic force and displacement data during the impact process are recorded to generate a dynamic force-displacement curve.

[0093] S42, compare the dynamic force-displacement curve with the engineering stress-displacement curve of the same honeycomb material;

[0094] S43, calculate the difference between the dynamic force value and the engineering stress value at the same displacement point, and define the curve formed by the difference sequence as the experimental dynamic overstress curve;

[0095] S44, On the boundary of the closed cavity, establish a functional relationship between the area of ​​the leakage hole and the pressure on the beam element network;

[0096] S45, set the same boundary conditions and impact velocity as the dynamic uniform compression test, and perform dynamic uniform compression simulation;

[0097] S46, Based on the results of dynamic uniform compression simulation, determine the undetermined parameters in the functional relationship between the area of ​​the leakage hole and the pressure on the beam element network, including:

[0098] S461, Establish a curve consisting of the difference sequence between the dynamic force-displacement curve obtained from dynamic uniform compression simulation and the dynamic force-displacement curve obtained from dynamic uniform compression test, as the simulated dynamic overstress curve.

[0099] S462, Based on the difference between the simulated dynamic overstress curve and the experimental dynamic overstress curve, adjust the undetermined parameter in the functional relationship between the area of ​​the leakage hole and the pressure on the beam element network;

[0100] S463, If the difference between the simulated dynamic overstress curve and the experimental dynamic overstress curve is greater than the preset overstress threshold, then return to S45 and repeat the dynamic uniform compression simulation.

[0101] If the difference between the simulated dynamic overstress curve and the experimental dynamic overstress curve is less than or equal to the preset overstress threshold, the calibration is determined to be complete, and the functional relationship between the area of ​​the leakage hole in the closed cavity and the pressure on the beam element network is output.

[0102] The leakage holes in the closed cavity are used to simulate the real coupling failure process during a collision, where the honeycomb wall is sheared and torn, creating a macroscopic tear that causes the high-pressure gas inside to escape from the macroscopic tear at an accelerated rate.

[0103] In one possible implementation, an aluminum honeycomb standard specimen of the same specifications as that used for quasi-static calibration in S2 is prepared, and a dynamic uniform compression test is performed on a drop hammer testing machine. The impact hammer mass is set to 300 kg, and the initial impact velocity is set to 10 m / s. Dynamic force and displacement data are simultaneously acquired throughout the impact process using a high-frequency force sensor and a high-speed camera mounted on the hammer head, generating a dynamic force-displacement curve.

[0104] Extract the engineering stress-displacement curve of the same material under quasi-static conditions obtained in S2. At the same displacement coordinate point, calculate the difference between dynamic force and quasi-static force. The difference sequence is defined as the experimental dynamic overstress curve, which characterizes the additional load contributed by the adiabatic compression of the air inside the honeycomb under dynamic loading.

[0105] In the completed beam element network finite element model, a completely closed cavity is defined inside the solid model using a layer of shell elements. The geometry of the cavity is consistent with the actual spatial contour inside the honeycomb solid. Fluid properties are assigned to the cavity. In this embodiment, the ideal gas law is adopted and the initial conditions are set as follows: pressure is standard atmospheric pressure, temperature is 293K, and adiabatic index is 1.4.

[0106] On the cavity shell element, a physical model describing gas leakage behavior is defined. The core is to establish a functional relationship between the effective area A of the leakage hole and the real-time pressure P in the cavity. Its general form is set as A=A0+k×P, where A0 is the reference leakage area, k is the pressure sensitivity coefficient, and A0 and k are undetermined parameters.

[0107] In the CAE software, the simulation conditions are set up to be completely identical to those in the dynamic test: the same model boundaries, the same impact velocity, and a set of initial guess parameters are assigned to the leakage function, such as A0 = 0.1 mm. 2 k=0.01mm 2 / MPa, run dynamic compression simulation, extract the dynamic force-displacement curve from the simulation results, and calculate the dynamic overstress curve. Compare the simulated dynamic overstress curve with the experimental dynamic overstress curve, and calculate the root mean square error of the two curves over the entire displacement range as the quantization difference. The preset overstress threshold is set to 5%. If the root mean square error is greater than the preset overstress threshold, it indicates that the air effect predicted by the simulation does not match the experiment, and further analysis of the difference is required. If the overall amplitude of the simulated dynamic overstress curve is too high, it indicates insufficient gas leakage. A0 and k should be increased to increase the leakage area. If the amplitude is too low, A0 and k should be decreased. After adjusting the parameters, return to step S45 and rerun the simulation. If the root mean square error is less than or equal to the preset overstress threshold, the calibration is considered complete.

[0108] This invention addresses the fundamental physical deficiency of completely neglecting the adiabatic compression effect of internal air within a highly efficient and homogeneous framework by integrating a closed cavity following the ideal gas law into a solid mechanics model, thereby improving simulation accuracy and reliability. Furthermore, by decoupling the contribution of pure air effects based on a comparison of dynamic and quasi-static experimental data, it solves the calibration challenge of separating and quantifying the air compression effect from complex coupled responses, achieving purified and quantitative extraction of the contribution of air compression as an independent physical mechanism, thus improving simulation accuracy and reliability. Finally, by establishing and calibrating the functional relationship between the leakage orifice area and the internal pressure, it creatively solves the problems of physical fidelity and model adjustability in gas leakage processes. Traditional methods, when considering air, often assume complete closure or fixed leakage orifices, which severely contradicts the physical reality of micropores and tear expansion in real honeycomb materials. This method, through a calibrable function, flexibly and realistically simulates the leakage process, achieving high-fidelity parametric simulation of gas leakage behavior and improving simulation accuracy.

[0109] S5, Establish a dynamic coupling mechanism to dynamically adjust the area of ​​the leakage holes in the closed cavity according to the real-time failure state of the beam elements in the beam element network during simulation, including:

[0110] S51, During the collision simulation calculation, the elongation of each beam element in the beam element network is monitored and recorded in real time;

[0111] S52, compare the elongation of each beam element monitored in real time with the second threshold. If the elongation of a beam element is found to be greater than the second threshold, it is determined to be a failed beam element.

[0112] S53, based on the spatial position of the failed beam element in the model, map and locate the corresponding region on the shell element wall of the closed cavity;

[0113] S54, according to the preset coupling rules, calculate the area of ​​additional leakage holes that should be activated or increased in the region corresponding to the failed beam element;

[0114] S55, repeat S51 until the collision simulation calculation process ends.

[0115] In one possible implementation, based on the calibration results of step S2, a failure displacement threshold has been defined for the beam element. In this embodiment, the second threshold is set to 0.5 mm. To achieve the mapping from mechanical failure to fluid leakage, coupling rules need to be predefined. This embodiment employs a simplified and effective linear relationship:

[0116] Ad = M × (L / L2) × A0

[0117] Where Ad is the area of ​​the additional leak hole to be activated, M is the coupling coefficient used to adjust the leakage intensity (preset to 0.1 in this example), L is the elongation recorded by the failed beam element at the time of failure, L2 is the second threshold (0.5 mm), and A0 is the baseline leak area, which is related to the size of a typical tear (preset to 0.2 mm in this example). 2 .

[0118] Assuming the simulation has begun and the model is under impact load, the system automatically executes the following loop at each computation time step of the solver:

[0119] The system traverses all beam elements in the beam element network. For the i-th beam element, its current length is read and recorded in real time, and its elongation relative to the initial length is calculated. The real-time elongation of each beam element is compared with a preset second threshold. If it is less than or equal to the second threshold, the element is considered normal, and no operation is performed on it in this step. If it is greater than the second threshold, the system immediately determines that the element is a failed beam element and triggers the subsequent coupling operation chain. The system records the ID of this failed element and its elongation at the moment of failure. For example, if the elongation reaches 0.52 mm, it performs a fast search in the shell element mesh representing the airbag boundary based on the spatial coordinates of the failed beam element. Using the nearest neighbor algorithm or a pre-generated mapping table, it finds the shell element closest to the failure point. The local area where this shell element is located is then positioned as the potential gas leakage area corresponding to the mechanical tear at this point.

[0120] Based on the preset coupling rules, the additional leakage hole area is calculated using the elongation data of the failed element. For example, for an element with an elongation of 0.52 mm, the calculated additional leakage hole area is 0.0208 mm². 2 This dynamically activates a leak hole attribute or increases the effective area of ​​an existing leak hole by 0.0208 mm. 2 .

[0121] As the impact continues, new beam elements may successively reach the failure threshold at different locations in the model, thereby continuously triggering the operation of dynamically increasing the leakage area at the corresponding locations on the airbag wall.

[0122] This invention, through a failure event triggering mechanism based on real-time simulation data, ensures strict causality and synchronicity between structural tearing and gas leakage on the simulation timeline. This allows the model to realistically reproduce the dynamic process of leakage occurring and evolving only with tearing in real collisions. A spatial mapping algorithm from failed beam elements to airbag shell elements ensures that gas only leaks from the corresponding location where structural damage actually occurs, achieving consistency between the leakage path and tearing path in spatial distribution. This greatly enhances the credibility and visualization interpretability of deformation and leakage modes in the simulation. Furthermore, by using coupling rules to quantitatively calculate the leakage area based on the degree of failure, the invention achieves quantified and gradient simulation of the leakage effect, more realistically influencing the pressure decay within the cavity and the overall dynamic mechanical response. This allows the model to capture subtle fluctuation characteristics caused by the propagation of local failures.

[0123] Example 2

[0124] like Figure 2 As shown, the present invention also provides a multiphysics finite element modeling system for honeycomb structures. The system is used to implement the multiphysics finite element modeling method for honeycomb structures described in any of Embodiment 1. The system includes:

[0125] The mesh generation module is used to establish a solid finite element model based on the geometric dimensions of the cellular barrier, and to mesh the solid finite element model.

[0126] The constitutive parameter calibration module is connected to the mesh generation module and is used to calibrate the structural parameters of the solid finite element model based on quasi-static uniform compression test data of honeycomb materials.

[0127] The network embedding module, connected to the constitutive parameter calibration module, is used to introduce physical gaps to regularly divide the continuous solid mesh in the plane, and to use discrete beam elements to connect the corresponding nodes on both sides of the physical gaps to generate a beam element network.

[0128] An air effect calibration module, connected to the network embedding module, is used to construct a closed cavity inside the beam element network based on the ideal gas law, and to calibrate the functional relationship between the area of ​​the leakage holes in the closed cavity and the pressure on the beam element network using dynamic uniform compression test data of the honeycomb material.

[0129] The dynamic coupling execution module, connected to the air effect calibration module, is used to establish a dynamic coupling mechanism to dynamically adjust the area of ​​the leakage holes in the closed cavity according to the real-time failure state of the beam elements in the beam element network during the simulation process.

[0130] Example 3

[0131] A computer-readable storage medium comprising computer program instructions that cause a computer to perform the steps of the multiphysics finite element modeling method for a cellular structure as described in any of Embodiment 1.

[0132] The computer-readable storage medium may be any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof.

[0133] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A multiphysics finite element modeling method for honeycomb structures, characterized in that, include: A solid finite element model is established based on the geometric dimensions of the cellular barrier, and the solid finite element model is meshed. The structural parameters of the solid finite element model were calibrated based on quasi-static uniform compression test data of honeycomb materials. Physical gaps are introduced to regularly divide the continuous solid mesh in the plane, and discrete beam elements are used to connect the corresponding nodes on both sides of the physical gaps to generate a beam element network. A closed cavity was constructed inside the beam element network based on the ideal gas law, and the functional relationship between the area of ​​the leakage holes in the closed cavity and the pressure on the beam element network was calibrated using dynamic uniform compression test data of honeycomb materials. A dynamic coupling mechanism is established to dynamically adjust the area of ​​the leakage holes in the closed cavity according to the real-time failure state of the beam elements in the beam element network during the simulation process. The quasi-static uniform compression test data based on honeycomb materials are used to calibrate the structural parameters of the solid finite element model, including: Standard samples of the honeycomb material were prepared and subjected to a quasi-static uniform compression test on a universal testing machine. Record the applied force and displacement during the experiment, calculate and generate engineering stress-displacement curves, and extract key mechanical characteristic parameters, including initial elastic modulus, yield stress, plateau stress, and compaction strain. A simulation model with the same geometric dimensions, constraints, and loading conditions as the standard specimen was established, and the same mesh generation was performed as for the preparation of the standard specimen. Assign anisotropic elastoplastic constitutive models to the solid elements in the simulation model; The obtained engineering stress-displacement curve is used as the target benchmark, and the platform stress is used as the core calibration target. Simulation is performed by repeatedly adjusting the input parameters in the constitutive model to generate simulation curves. The calibration is considered complete when the platform stress value of the simulation curve matches the platform stress measured by the quasi-static uniform compression test, and the overall shape of the simulation curve is highly consistent with the engineering stress-displacement curve. The calibration of the functional relationship between the area of ​​the leakage holes in the closed cavity and the pressure on the beam element network using dynamic uniform compression test data of honeycomb materials includes: A standard sample of the honeycomb material was prepared and subjected to a dynamic uniform compression test. The sample was impacted with a preset strain rate to simulate the loading conditions during the collision process. The dynamic force and displacement data during the impact process were recorded to generate a dynamic force-displacement curve. The dynamic force-displacement curve is compared with the engineering stress-displacement curve of the same honeycomb material; Calculate the difference between the dynamic force value and the engineering stress value at the same displacement point, and define the curve formed by the difference sequence as the experimental dynamic overstress curve; On the boundary of the closed cavity, establish a functional relationship between the area of ​​the leakage hole and the pressure on the beam element network; Set the same boundary conditions and impact velocity as the dynamic uniform compression test, and perform dynamic uniform compression simulation. Based on the results of dynamic uniform compression simulation, the undetermined parameters in the functional relationship between the area of ​​the leakage hole and the pressure on the beam element network are determined.

2. The multiphysics finite element modeling method for honeycomb structures according to claim 1, characterized in that, The elongation of the beam element is calculated based on the applied pressure in three ways, including: In the linear elastic segment, if the pressure on the beam element is less than or equal to the first threshold, the elongation of the beam element is directly proportional to the pressure. In the plastic platform segment, if the pressure on the beam element is greater than the first threshold and less than or equal to the second threshold, the elongation of the beam element is a constant value. In the failure stage, if the pressure on the beam element is greater than the second threshold, the elongation of the beam element is a preset maximum value, which is used to simulate the failure process of the beam element.

3. The multiphysics finite element modeling method for honeycomb structures according to claim 1, characterized in that, The undetermined parameters for determining the functional relationship between the area of ​​the leakage hole and the pressure on the beam element network based on the results of dynamic uniform compression simulation include: A curve consisting of the difference sequence between the dynamic force-displacement curve obtained from dynamic uniform compression simulation and the dynamic force-displacement curve obtained from dynamic uniform compression test is established as the simulated dynamic overstress curve. The undetermined parameters in the functional relationship between the area of ​​the leakage hole and the pressure on the beam element network are adjusted based on the difference between the simulated dynamic overstress curve and the experimental dynamic overstress curve. If the difference between the simulated dynamic overstress curve and the experimental dynamic overstress curve is greater than the preset overstress threshold, then the dynamic uniform compression simulation is repeated. If the difference between the simulated dynamic overstress curve and the experimental dynamic overstress curve is less than or equal to the preset overstress threshold, the calibration is determined to be complete, and the functional relationship between the area of ​​the leakage hole in the closed cavity and the pressure on the beam element network is output.

4. The multiphysics finite element modeling method for honeycomb structures according to claim 1, characterized in that, The step of dynamically adjusting the area of ​​the leakage holes in the closed cavity based on the real-time failure status of the beam elements in the beam element network includes: During the collision simulation calculation, the elongation of each beam element in the beam element network is monitored and recorded in real time. The elongation of each beam element is monitored in real time and compared with the second threshold. If the elongation of a beam element is found to be greater than the second threshold, it is determined to be a failed beam element. Based on the spatial position of the failed beam element in the model, the corresponding region is mapped and located on the shell element wall of the closed cavity. Based on the preset coupling rules, calculate the area of ​​additional leakage holes that should be activated or increased in the region corresponding to the failed beam element; The process is repeated until the collision simulation calculation is completed.

5. The multiphysics finite element modeling method for honeycomb structures according to claim 1, characterized in that, The leakage holes in the closed cavity are used to simulate the real coupling failure process during a collision, where the honeycomb wall is sheared and torn, creating a macroscopic tear that causes the high-pressure gas inside to escape from the macroscopic tear at an accelerated rate.

6. A multiphysics finite element modeling system for honeycomb structures, characterized in that, The system is used to implement the multiphysics finite element modeling method for the honeycomb structure according to any one of claims 1 to 5, and the system includes: The mesh generation module is used to establish a solid finite element model based on the geometric dimensions of the cellular barrier, and to mesh the solid finite element model. The constitutive parameter calibration module is connected to the mesh generation module and is used to calibrate the structural parameters of the solid finite element model based on quasi-static uniform compression test data of honeycomb materials. The network embedding module, connected to the constitutive parameter calibration module, is used to introduce physical gaps to regularly divide the continuous solid mesh in the plane, and to use discrete beam elements to connect the corresponding nodes on both sides of the physical gaps to generate a beam element network. An air effect calibration module, connected to the network embedding module, is used to construct a closed cavity inside the beam element network based on the ideal gas law, and to calibrate the functional relationship between the area of ​​the leakage holes in the closed cavity and the pressure on the beam element network using dynamic uniform compression test data of the honeycomb material. The dynamic coupling execution module, connected to the air effect calibration module, is used to establish a dynamic coupling mechanism to dynamically adjust the area of ​​the leakage holes in the closed cavity according to the real-time failure state of the beam elements in the beam element network during the simulation process.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores instructions that, when executed on a terminal device, cause the terminal device to perform the multiphysics finite element modeling method for cellular structures as described in any one of claims 1 to 5.

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