Simulation method, device and equipment for composite material automobile roof
By obtaining the material parameters of composite automotive roofs through layered modeling and performing simulation benchmarking, the problem of low simulation accuracy in existing technologies is solved, and accurate simulation of roofs under complex working conditions is achieved, providing a design basis.
Patent Information
- Application Number
- CN202410665149.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-27
- Publication Date
- 2025-11-28
AI Technical Summary
Existing simulation modeling methods for automotive roofs fail to accurately simulate the bending and tearing failure effects of composite materials under stress, resulting in low simulation accuracy and an inability to accurately predict the mechanical properties of the roof under various working conditions.
A layered modeling method was adopted to obtain the material parameters of different layered material samples at different temperatures and strain rates. The accuracy of the parameters was verified by material experiments and simulations, and iterative optimization was carried out. These parameters were used for simulation modeling, taking into account the connection and force transmission between the material layers.
It improves the accuracy of simulation modeling, enabling accurate simulation of the mechanical performance of the ceiling under various complex working conditions, and provides a theoretical basis for the design of the ceiling and its surrounding interior components.
Smart Images
Figure CN121030906A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of vehicle technology, and in particular to a simulation method, apparatus and equipment for composite material automobile roofs. Background Technology
[0002] With the improvement of people's living standards and the rapid development of the social economy, the usage rate of cars has gradually increased, and more and more cars have entered people's lives, bringing great convenience to all aspects of people's lives.
[0003] Automotive roofs are typically made of composite materials, such as PU foam, fiberglass, non-woven fabric, sponge, and fabric, manufactured through complex molding processes including adhesive spraying and pressing. Currently, in automotive industry simulation analysis, a simplified modeling method is commonly used for automotive roofs. This method ignores the composite materials and molding process of the roof, treating it as a homogeneous material and assigning it isotropic material properties. However, this simulation modeling method has low accuracy and cannot accurately simulate the bending and tearing failure effects of the roof under stress. Consequently, this simulation modeling method cannot accurately predict the mechanical performance of the roof under various working conditions such as air curtain detonation, resulting in poor simulation modeling results. Summary of the Invention
[0004] The main objective of this application is to provide a simulation method, apparatus, and equipment for composite material car roofs. This method can model the car roof by layering composite materials, fully considering the influence of materials with different physical properties on the mechanical properties of the roof, thereby effectively improving the accuracy and effect of simulation modeling.
[0005] This application provides a simulation method for composite material automotive roofs, including:
[0006] Obtain material samples of different layers on the roof of the target vehicle, and obtain the material parameters of the different layers of material samples at different temperatures and strain rates; the different layers of material samples include polyurethane (PU) foam layer material samples, non-woven fabric plus glass fiber composite material layer material samples, sponge layer material samples, and fabric layer material samples; the material parameters include at least one of elastic modulus, Poisson's ratio, and stress-strain curve;
[0007] Obtain an overall sample of the target vehicle roof, and conduct material tests and simulation benchmarks on the overall sample to verify whether the material parameters of the different layered material samples are accurate under different temperatures and strain rates;
[0008] If so, the target vehicle roof is simulated and modeled using the material parameters to obtain the simulation modeling results.
[0009] In one optional implementation, obtaining the material parameters of the different layered material samples at different temperatures and strain rates includes:
[0010] Compression tests were conducted on the PU foam layer material samples to obtain their material parameters at different temperatures and strain rates.
[0011] Tensile and compression tests were conducted on the nonwoven fabric-glass fiber composite material sample to obtain its material parameters at different temperatures and strain rates.
[0012] Compression tests were conducted on the sponge layer material sample to obtain its material parameters at different temperatures and strain rates.
[0013] Orthogonal biaxial tensile tests were conducted on the fabric layer material samples to obtain their material parameters at different temperatures and strain rates.
[0014] In one optional implementation, the tensile and compression tests performed on the nonwoven fabric-glass fiber composite material sample to obtain its material parameters at different temperatures and strain rates include:
[0015] The nonwoven fabric and glass fiber composite material sample was divided into K regions using the stiffness method. Tensile and compression tests were conducted on the samples that met the test sample requirements in the K regions to obtain their elastic modulus and stress-strain curves at different temperatures and strain rates, which were used as material parameters. K is a positive integer greater than 0.
[0016] In one optional implementation, after conducting material tests and simulations on the overall sample to verify the accuracy of the material parameters of the different layered material samples at different temperatures and strain rates, the method further includes:
[0017] If it is verified that the material parameters of the different layered material samples are inaccurate at different temperatures and strain rates, then the material parameters whose errors do not meet the preset conditions will be iteratively optimized until the preset conditions are met.
[0018] In one optional implementation, the simulation of the target vehicle roof using material parameters of the different layered material samples at different temperatures and strain rates, to obtain simulation modeling results, includes:
[0019] The roof of the target vehicle is divided into layers and meshed, and the material parameters of the material samples of different layers under different temperatures and strain rates are respectively assigned to the mesh elements of the corresponding material layers; among them, the PU foam layer and the sponge layer are meshed using solid elements, while the non-woven fabric plus glass fiber composite material layer and the fabric layer are meshed using shell elements.
[0020] Establish connections between different material layers of the target vehicle roof to realize the transmission of forces between the material layers, so as to form the target vehicle roof into a whole for simulation and obtain simulation modeling results.
[0021] In one optional implementation, the different temperatures fall within the range of [-35°, 85°]; the different strain rates fall within the range of [0.01 / s, 100 / s].
[0022] Corresponding to the above-mentioned simulation method for composite material car roofs, this application proposes a simulation device for composite material car roofs, comprising:
[0023] The first acquisition unit is used to acquire material samples of different layers on the roof of the target vehicle, and to acquire the material parameters of the different layers of material samples at different temperatures and strain rates; the different layers of material samples include polyurethane (PU) foam layer material samples, non-woven fabric plus glass fiber composite material layer material samples, sponge layer material samples, and fabric layer material samples; the material parameters include at least one of elastic modulus, Poisson's ratio, and stress-strain curve;
[0024] The second acquisition unit is used to acquire the overall sample of the target vehicle roof and to conduct material tests and simulation benchmarks on the overall sample to verify whether the material parameters of the different layered material samples are accurate under different temperatures and strain rates.
[0025] The simulation unit is used to simulate and model the roof of the target vehicle using the material parameters if it is verified that the material parameters of the different layered material samples are accurate at different temperatures and strain rates, and to obtain the simulation modeling results.
[0026] In one optional implementation, the first acquisition unit includes:
[0027] The first test subunit is used to conduct compression tests on the PU foam layer material sample to obtain its material parameters at different temperatures and strain rates.
[0028] The second test subunit is used to conduct tensile and compression tests on the nonwoven fabric and glass fiber composite material sample to obtain its material parameters at different temperatures and strain rates.
[0029] The third test subunit is used to conduct compression tests on the sponge layer material sample to obtain its material parameters at different temperatures and strain rates.
[0030] The fourth test subunit is used to conduct orthogonal biaxial tensile tests on the fabric layer material sample to obtain its material parameters at different temperatures and strain rates.
[0031] In one alternative implementation, the second experimental subunit is specifically used for:
[0032] The nonwoven fabric and glass fiber composite material sample was divided into K regions using the stiffness method. Tensile and compression tests were conducted on the samples that met the test sample requirements in the K regions to obtain their elastic modulus and stress-strain curves at different temperatures and strain rates, which were used as material parameters. K is a positive integer greater than 0.
[0033] In one alternative implementation, the apparatus further includes:
[0034] The optimization unit is used to iteratively optimize the material parameters that do not meet the preset conditions if it is verified that the material parameters of the material samples with different layers are inaccurate at different temperatures and strain rates, until the preset conditions are met.
[0035] In one optional implementation, the simulation unit includes:
[0036] Layered sub-units are used to divide the target vehicle roof into layers and assign the material parameters of the material samples of different layers at different temperatures and strain rates to the corresponding material layer's mesh unit; among them, the PU foam layer and sponge layer are divided into solid units, while the non-woven fabric plus glass fiber composite material layer and fabric layer are divided into shell units.
[0037] Sub-units are established to connect different material layers of the target vehicle roof, enabling the transmission of forces between the material layers, so as to form the target vehicle roof as a whole for simulation and obtain simulation modeling results.
[0038] In one optional implementation, the different temperatures fall within the range of [-35°, 85°]; the different strain rates fall within the range of [0.01 / s, 100 / s].
[0039] This application embodiment also provides a simulation device for a composite material automobile roof, including: a processor, a memory, and a system bus;
[0040] The processor and the memory are connected via the system bus;
[0041] The memory is used to store one or more programs, the one or more programs including instructions, which, when executed by the processor, cause the processor to perform any of the above-described implementations of the simulation method for composite material car roofs.
[0042] This application 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 above-described simulation methods for composite material car roofs.
[0043] Therefore, the embodiments of this application have the following beneficial effects:
[0044] This application provides a simulation method, apparatus, and equipment for composite material automotive roofs. First, material samples of different layers on the target vehicle roof are obtained, and their material parameters are acquired at different temperatures and strain rates. These samples include polyurethane (PU) foam layer samples, non-woven fabric with glass fiber composite layer samples, sponge layer samples, and fabric layer samples. Material parameters include at least one of elastic modulus, Poisson's ratio, and stress-strain curves. Then, a complete sample of the target vehicle roof is obtained, and material tests and simulations are performed on the complete sample to verify the accuracy of the obtained material parameters. If accurate, the material parameters are used to simulate and model the target vehicle roof, yielding simulation results. This method, by simulating and modeling the target vehicle roof using a layered composite material approach, fully considers the influence of various materials with different physical properties on the roof's mechanical properties, effectively improving the accuracy and effectiveness of the simulation modeling. Attached Figure Description
[0045] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0046] Figure 1 A flowchart illustrating a simulation method for a composite material automotive roof provided in this application embodiment;
[0047] Figure 2 This is a schematic diagram illustrating the different material layers of the target vehicle roof provided in an embodiment of this application;
[0048] Figure 3 Example diagram of stress-strain curves provided in embodiments of this application;
[0049] Figure 4 This is a schematic diagram of the composition of a simulation device for a composite material car roof provided in an embodiment of this application. Detailed Implementation
[0050] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0051] Currently, when simulating and modeling composite automotive roofs, a simplified modeling method is usually adopted. This method does not consider the composite material and molding process of the roof and directly treats the roof as a homogeneous material, assigning it isotropic material properties. However, this simulation modeling method has low accuracy and cannot accurately simulate the bending and tearing failure effects of the automotive roof under stress. As a result, this simulation modeling method cannot accurately predict the mechanical performance of the roof under various working conditions such as air curtain detonation, and therefore cannot provide an effective reference for the design of the roof and its surrounding interior parts before physical testing.
[0052] Based on this, this application proposes a simulation method, device, and equipment for composite material automotive roofs. By modeling the automotive roof in a layered manner, each layer is assigned different material physical properties. Compared with existing simplified modeling methods, this application fully considers the influence of various materials with different physical properties on the mechanical properties of the roof, resulting in higher modeling accuracy. Furthermore, it can accurately simulate the mechanical performance of the roof under various complex working conditions using simulation software, thereby providing more theoretical basis and effective reference for the design of the roof and its surrounding interior components before physical testing.
[0053] The simulation method for composite material automotive roofs provided in this application will be described in detail below with reference to the accompanying drawings. See also Figure 1 The diagram shows a flowchart of an embodiment of a simulation method for a composite material automotive roof provided in this application. This embodiment may include the following steps:
[0054] S101: Obtain material samples of different layers on the roof of the target vehicle, and obtain the material parameters of the material samples of different layers at different temperatures and strain rates; wherein, the material samples of different layers include polyurethane (PU) foam layer material samples, non-woven fabric plus glass fiber composite material layer material samples, sponge layer material samples, and fabric layer material samples; the material parameters include at least one of elastic modulus, Poisson's ratio, and stress-strain curve.
[0055] In this embodiment, any vehicle whose roof is modeled using the method of this application is defined as the target vehicle. To improve the simulation modeling effect of the target vehicle's roof, this application proposes a method for modeling the car roof by layering composite materials. The aim is to fully consider the influence of materials with different physical properties on the mechanical properties of the roof, thereby improving the accuracy of the simulation modeling. The structure of the target vehicle's roof is as follows: Figure 2 As shown, according to the material type, it can be divided into four different layers: polyurethane (PU) foam layer, non-woven fabric plus glass fiber composite layer, sponge layer, and fabric layer, each layer having different material physical properties.
[0056] To simulate and model a car roof using a layered composite material approach, material samples of different layers can first be extracted from the target vehicle's roof. These samples include, but are not limited to, PU foam layer samples, non-woven fabric plus glass fiber composite layer samples, sponge layer samples, and fabric layer samples. Then, layered material tests are conducted on these samples to obtain material parameters for each layer at different temperatures and strain rates, including but not limited to at least one of the following: elastic modulus, Poisson's ratio, and stress-strain curves.
[0057] In this application, no specific values are limited for different temperatures and strain rates in the test conditions. These values can be set according to actual conditions and empirical values. One possible implementation is to set the range of different temperatures to [-35°, 85°], such as high temperature 85°, normal temperature 25°, and low temperature -35°, and to set the range of different strain rates to [0.01 / s, 100 / s], such as 0.01 / s, 0.1 / s, 1 / s, 10 / s, 100 / s, etc.
[0058] Specifically, one optional implementation method is that the process of "obtaining material parameters of material samples with different layers at different temperatures and strain rates" in step S101 may include the following steps S1011-S1014:
[0059] S1011: Compression tests are conducted on PU foam layer material samples to obtain their material parameters at different temperatures and strain rates.
[0060] In this implementation, to improve simulation accuracy, this application uses material testing to obtain the physical properties (i.e., material parameters) of material samples with different layers at different temperatures and strain rates, which are then used as material parameter inputs for subsequent simulation modeling. Specifically, for the PU foam layer material sample, this application obtains its material parameters (including but not limited to elastic modulus, Poisson's ratio, and stress-strain curve) at different temperatures and strain rates by performing compression tests on it.
[0061] This application does not limit the specific implementation method of the compression test on the PU foam material sample. In order to improve the accuracy of the test, the compression test on the PU foam material sample is carried out in accordance with the international standard ISO3386-1 "Polymeric materials, cellular flexible - Determination of stress-strain characteristics in compression - Part 1: Low-density materials". After obtaining the Poisson's ratio and stress-strain curve through the test, the data points between 0.05% and 0.25% of the strain on the stress-strain curve are first obtained. Then, the slope of the straight line obtained by linear fitting is used as the elastic modulus. In addition, considering the influence of temperature and strain rate on the physical properties of the material, one implementation method is that the test conditions used in this application can include high temperature 85°C, room temperature 25°C and low temperature -35°C, and five strain rates of 0.01 / s, 0.1 / s, 1 / s, 10 / s and 100 / s are set at each temperature. Five samples are measured at each strain rate, and the average value of three valid measurement results is selected as the final material parameters. For example, assuming a PU foam layer material sample has a Poisson's ratio of 0.3 and an elastic modulus of 50 MPa measured at room temperature and 0.1 / s, the stress-strain curve can be as follows: Figure 3 As shown.
[0062] S1012: Tensile and compression tests were conducted on samples of nonwoven fabric with glass fiber composite material to obtain material parameters at different temperatures and strain rates.
[0063] In this implementation, for the nonwoven fabric plus glass fiber composite material sample, this application obtains its material parameters (including but not limited to elastic modulus and stress-strain curve) at different temperatures and strain rates by conducting tensile and compression tests on it.
[0064] This application does not limit the specific implementation method used for tensile and compression tests on the nonwoven fabric plus glass fiber composite material sample. One optional implementation method is to treat the nonwoven fabric and glass fiber of the target vehicle roof frame as a whole, considering it as a composite material whose physical properties are related to the glass fiber content. Therefore, based on the different glass fiber content added in different areas during the roof pressing process, the roof can be divided into several areas. Another optional implementation method is to use the stiffness method to divide the nonwoven fabric plus glass fiber composite material sample into K (the specific value is not limited, but must be a positive integer greater than 0). The process involves first uniformly selecting points on the ceiling to measure stiffness, where stiffness = force (N) / displacement (mm). The stiffness measurement results are then divided into several gradients. Based on these stiffness gradients, the ceiling is further divided into several (K) regions. For example, when the stiffness range is 10-50, it can be divided into four gradients. Points with stiffness between 10-20 can be grouped into one region, points with stiffness between 20-30 into another, and so on. The more stiffness gradients, the more regions are divided, the more material parameters are measured, and the higher the accuracy of the entire ceiling frame. In each of these K regions, several samples are taken according to the test specimen requirements for material testing (including but not limited to in-plane tension and compression). The elastic modulus and stress-strain curves of the material at different temperatures and strain rates are obtained and used as material property parameters input into the simulation model (software).
[0065] To improve the accuracy of the tests, this application conducts tensile tests on nonwoven fabric and glass fiber composite material samples according to the international standard ISO-527-2 "Plastics - Determination of tensile properties - Part 2: Test conditions for moulding and extrusion plastics", and compression tests according to the international standard ISO9895 "Paper and board Compressive strength - Short-span test". After obtaining the stress-strain curve through the tests, data points between 0.05% and 0.25% strain on the stress-strain curve are first acquired. Then, the slope of the straight line obtained by linear fitting is used as the elastic modulus. Considering the influence of temperature and strain rate on the physical properties of the material, one implementation method is that the test conditions used in this application can include high temperature 85°C, normal temperature 25°C, and low temperature -35°C, and five strain rates of 0.01 / s, 0.1 / s, 1 / s, 10 / s, and 100 / s are set at each temperature. Five samples are measured at each strain rate, and the average of three valid measurement results is selected as the final material parameters.
[0066] S1013: Perform compression tests on sponge layer material samples to obtain their material parameters at different temperatures and strain rates.
[0067] In this implementation, for the sponge layer material sample, this application obtains its material parameters (including but not limited to elastic modulus, Poisson's ratio and stress-strain curve) at different temperatures and strain rates by performing compression tests on it.
[0068] This application does not limit the specific implementation method of the compression test on the sponge layer material sample. In order to improve the accuracy of the test, the compression test on the sponge layer material sample is carried out in accordance with the international standard ISO3386-1 "Polymeric materials, cellular flexible - Determination of stress-strain characteristics in compression - Part 1: Low-density materials". After obtaining the Poisson's ratio and stress-strain curve through the test, the data points between 0.05% and 0.25% of the strain on the stress-strain curve are first obtained. Then, the slope of the straight line obtained by linear fitting is used as the elastic modulus. In addition, considering the influence of temperature and strain rate on the physical properties of the material, one implementation method is that the test conditions used in this application can include high temperature 85°C, room temperature 25°C and low temperature -35°C, and five strain rates of 0.01 / s, 0.1 / s, 1 / s, 10 / s and 100 / s are set at each temperature. Five samples are measured at each strain rate, and the average value of three valid measurement results is selected as the final material parameters.
[0069] S1014: Conduct orthogonal biaxial tensile tests on fabric layer material samples to obtain their material parameters at different temperatures and strain rates.
[0070] In this implementation, for the fabric layer material sample, this application obtains its material parameters (including but not limited to elastic modulus and stress-strain curve) at different temperatures and strain rates by conducting orthogonal biaxial tensile tests on it.
[0071] This application does not limit the specific implementation method of the compression test on the sponge layer material sample. In order to improve the accuracy of the test, the orthogonal biaxial tensile test on the sponge layer material sample is carried out in accordance with the international standard ISO13934-1 "Textiles—Tensile properties of fabrics—Part 1: Determination of maximum force and elongation at maximum force using the strip method". After obtaining the stress-strain curve through the test, the data points between 0.05% and 0.25% of the strain on the stress-strain curve are first obtained. Then, the slope of the straight line obtained by linear fitting is the elastic modulus. Considering the influence of temperature and strain rate on the physical properties of the material, one implementation method is that the test conditions used in this application can include high temperature 85°C, normal temperature 25°C and low temperature -35°C, and five strain rates of 0.01 / s, 0.1 / s, 1 / s, 10 / s and 100 / s are set at each temperature. Five samples are measured at each strain rate, and the average value of three valid measurement results is selected as the final material parameters.
[0072] S102: Obtain the overall sample of the target vehicle roof and conduct material tests and simulation benchmarks on the overall sample to verify whether the material parameters of the different layered material samples are accurate under different temperatures and strain rates.
[0073] It should be noted that since step S101 above obtains the material parameters of different layered material samples at different temperatures and strain rates through layered material testing, and the test itself will have certain errors, it is necessary to conduct material testing and simulation benchmarking of the entire roof of the target vehicle to verify whether the material parameters of different layered material samples at different temperatures and strain rates are accurate. If so, the subsequent step S103 is continued; if not, the material parameters whose errors do not meet the preset conditions (the specific content is not limited and can be set according to the actual situation and empirical values) can be iteratively optimized until the preset conditions are met.
[0074] This application does not limit the specific implementation method of material testing and simulation benchmarking for the entire roof of the target vehicle. One optional implementation method is to use in-plane tensile, compression, and three-point bending tests. In order to improve the accuracy of the test, the tensile test of the entire roof of the target vehicle is conducted according to the international standard ISO-527-2 "Plastics - Determination of tensile properties - Part 2: Test conditions forming and extrusion plastics", the compression test is conducted according to the international standard ISO9895 "Paper and board Compressive strength - Short-span test", and the three-point bending test is conducted according to the international standard ISO178 "Plastics - Determination of flexural properties". Then, the accuracy of the material parameters is verified by benchmarking the simulation results with the test results. At the same time, existing or future optimization software (such as LS-opt software) is used to iteratively optimize the material parameters with large errors to improve the accuracy of the roof material parameters.
[0075] Specifically, one possible approach is to conduct material testing and simulation benchmarking on the entire roof of the target vehicle to verify whether the material parameters obtained through layered testing can effectively simulate the overall mechanical properties of the roof. First, material testing can be conducted under specific temperature and strain rate conditions, such as room temperature (25°C) and a strain rate of 0.1 / s. Then, a complete sample (containing all material layers mentioned in the previous steps) is taken from a specific area of the target vehicle roof and subjected to material testing (including but not limited to in-plane tension, compression, and three-point bending tests). The measured values from the tests are selected as benchmarks; for example, force-displacement curves are selected for tension and compression tests, and force-deflection curves are selected for three-point bending tests. The test data are then recorded. Next, a simulation model of the overall ceiling sample is established in existing or future simulation software (such as LS-DYNA). This includes building a layered mesh model, establishing material properties and inputting material parameters obtained from layered material tests, assigning material properties to each material layer, and establishing connections between material layers. Then, simulations are performed under the same conditions as the overall ceiling material tests (i.e., simulations of tensile, compression, and three-point bending tests). The simulation results are then compared with the test results (e.g., comparing the differences between the test curves and the simulation curves) to verify the accuracy of the material parameters. At the same time, LS-opt software is used to iteratively optimize material parameters whose errors do not meet the preset conditions to improve the accuracy of the material parameters.
[0076] For example, the average error between the experimental curve and the simulation curve can be calculated. If the average error is less than 10%, the material parameters measured in the experiment are considered accurate. If the average error exceeds 10%, the material parameters need to be corrected. Parameter correction can be achieved using the DOE method and simulation software (such as LS-opt software). Taking the iterative optimization of the stress-strain curve of nonwoven fabric with glass fiber composite material as an example, firstly, the stress on the stress-strain curve can be selected as a variable, a reasonable variable range can be determined, and sample tests can be designed. Then, the simulation curve of each sample can be obtained through simulation, the error can be calculated, and then the sample with the smaller error can be selected as the starting point for the next iteration. This process is repeated until the error between the force-displacement curve and the force-deflection curve of a certain sample and the experimental curve is less than 10%, at which point the iterative optimization ends. It should be noted that the experimental conditions that can be selected during the iterative optimization in this application can also include high temperature 85°C, normal temperature 25°C, and low temperature -35°C, and five strain rates of 0.01 / s, 0.1 / s, 1 / s, 10 / s, and 100 / s can be set at each temperature.
[0077] S103: If so, then use the material parameters to simulate and model the roof of the target vehicle to obtain the simulation modeling results.
[0078] In this embodiment, if the material parameters of the material samples with different layers are verified to be accurate at different temperatures and strain rates, these material parameters, as well as existing or future simulation software (the specific structure is not limited and can be selected according to the actual situation and empirical values, such as LS-DYNA in Computer-Aided Engineering (CAE) as simulation software), can be used to simulate and model the roof of the target vehicle to obtain the simulation modeling results.
[0079] Specifically, one possible approach is to first mesh the target vehicle roof in simulation software (such as CAE preprocessing software) by dividing it into layers, and then assigning the material parameters of different layers of material samples at different temperatures and strain rates to the corresponding mesh elements of the material layers. Specifically, the PU foam layer and sponge layer are meshed using solid elements, while the non-woven fabric plus glass fiber composite layer and the fabric layer are meshed using shell elements. Then, connections can be established between the different material layers of the target vehicle roof to achieve force transfer between them, thus forming the target vehicle roof as a whole for simulation and obtaining the simulation modeling results.
[0080] In this implementation, during simulation modeling, the target vehicle roof is first meshed in simulation software (such as CAE preprocessing software) based on the roof geometry data. The PU foam layer and sponge layer are meshed using solid elements, while the non-woven fabric plus glass fiber composite layer and the fabric layer are meshed using shell elements. Then, the material parameters obtained experimentally in step S101 are assigned to the mesh elements of different material layers. For example, a MAT24 material card can be created in LS-DYNA software, the elastic modulus and stress-strain curves can be input, shell element properties can be created, and the material can be assigned to the shell element properties, which are then assigned to the shell element mesh. Next, connections between the various material layers of the roof are established. These connections can be simulated through shared nodes or by creating adhesive elements, thereby enabling force transmission between the material layers and making the roof a unified whole. Finally, after establishing a simulation model of the target vehicle's roof in LS-DYNA, this model can be integrated with simulation models of the side curtain airbags, interior trim, and body to establish a connection, resulting in a simulation model of the side curtain airbag subsystem. Then, the side curtain airbag detonation parameters are set, and detonation simulation calculations are performed to obtain simulation results. By observing the simulation results, the contact between the airbag and the roof during airbag deployment can be observed, as well as the roof's deformation, bending, and tearing failures during detonation, and the interior trim's detachment and breakage failures. The simulation results can also output the contact force between the roof and interior trim parts, the force on the interior trim clips, etc., providing more theoretical basis and effective reference for the design of the roof and its surrounding interior trim parts.
[0081] Thus, by executing steps S101-S103 above, and employing a layered modeling method, the composite material roof of the target vehicle is first layered according to the target vehicle's roof structure. Material tests are then conducted on each layer to obtain the material parameters required for simulation. Finally, material tests are performed on the entire roof, and the accuracy of the material parameters is verified through simulation benchmarking. Simultaneously, errors are corrected through iterative optimization. This fully considers the influence of the layered structure of the composite material target vehicle roof and the physical properties of each layer on the simulation results. Compared with traditional simplified modeling methods for automotive roofs, the composite material automotive roof simulation method proposed in this application has higher accuracy and can simulate the deformation, bending, and tearing failures of automotive roofs under various complex working conditions. Furthermore, because this application considers the changes in material properties under high and low temperatures and different strain rates, it is applicable to simulation analyses related to automotive roofs under different temperature and strain rate conditions, such as simulation analysis of side curtain airbag detonation, thus broadening its application scenarios.
[0082] In summary, this embodiment provides a simulation method for a composite material automotive roof. First, material samples of different layers on the target vehicle roof are obtained, and their material parameters are acquired at different temperatures and strain rates. These different layered material samples include polyurethane (PU) foam layer samples, non-woven fabric with glass fiber composite layer samples, sponge layer samples, and fabric layer samples. The material parameters include at least one of elastic modulus, Poisson's ratio, and stress-strain curves. Then, a complete sample of the target vehicle roof is obtained, and material tests and simulations are performed on the complete sample to verify the accuracy of the obtained material parameters. If accurate, the material parameters are used to simulate and model the target vehicle roof, yielding simulation results. This method, by simulating and modeling the target vehicle roof using a layered composite material approach, fully considers the influence of various materials with different physical properties on the roof's mechanical properties, effectively improving the accuracy and effectiveness of the simulation modeling.
[0083] See Figure 4 As shown, this application also provides an embodiment of a simulation device for a composite material automobile roof, which may include:
[0084] The first acquisition unit 401 is used to acquire material samples of different layers on the roof of the target vehicle, and to acquire the material parameters of the different layers of material samples at different temperatures and strain rates; the different layers of material samples include polyurethane (PU) foam layer material samples, non-woven fabric plus glass fiber composite material layer material samples, sponge layer material samples, and fabric layer material samples; the material parameters include at least one of elastic modulus, Poisson's ratio, and stress-strain curve;
[0085] The second acquisition unit 402 is used to acquire the overall sample of the target vehicle roof and to conduct material tests and simulation benchmarks on the overall sample to verify whether the material parameters of the different layered material samples are accurate under different temperatures and different strain rates.
[0086] The simulation unit 403 is used to perform simulation modeling on the roof of the target vehicle using the material parameters if it is verified that the material parameters of the material samples with different layers are accurate at different temperatures and strain rates, and to obtain the simulation modeling results.
[0087] In some possible implementations of this application, the first acquisition unit 401 includes:
[0088] The first test subunit is used to conduct compression tests on the PU foam layer material sample to obtain its material parameters at different temperatures and strain rates.
[0089] The second test subunit is used to conduct tensile and compression tests on the nonwoven fabric and glass fiber composite material sample to obtain its material parameters at different temperatures and strain rates.
[0090] The third test subunit is used to conduct compression tests on the sponge layer material sample to obtain its material parameters at different temperatures and strain rates.
[0091] The fourth test subunit is used to conduct orthogonal biaxial tensile tests on the fabric layer material sample to obtain its material parameters at different temperatures and strain rates.
[0092] In some possible implementations of this application, the second experimental subunit is specifically used for:
[0093] The nonwoven fabric and glass fiber composite material sample was divided into K regions using the stiffness method. Tensile and compression tests were conducted on the samples that met the test sample requirements in the K regions to obtain their elastic modulus and stress-strain curves at different temperatures and strain rates, which were used as material parameters. K is a positive integer greater than 0.
[0094] In some possible implementations of this application, the apparatus further includes:
[0095] The optimization unit is used to iteratively optimize the material parameters that do not meet the preset conditions if it is verified that the material parameters of the material samples with different layers are inaccurate at different temperatures and strain rates, until the preset conditions are met.
[0096] In some possible implementations of this application, the simulation unit 403 includes:
[0097] Layered sub-units are used to divide the target vehicle roof into layers and assign the material parameters of the material samples of different layers at different temperatures and strain rates to the corresponding material layer's mesh unit; among them, the PU foam layer and sponge layer are divided into solid units, while the non-woven fabric plus glass fiber composite material layer and fabric layer are divided into shell units.
[0098] Sub-units are established to connect different material layers of the target vehicle roof, enabling the transmission of forces between the material layers, so as to form the target vehicle roof as a whole for simulation and obtain simulation modeling results.
[0099] In some possible implementations of this application, the range of the different temperatures is [-35°, 85°]; the range of the different strain rates is [0.01 / s, 100 / s].
[0100] As can be seen from the above embodiments, the simulation device for composite material car roofs provided in this application first acquires material samples of different layers on the target vehicle roof, and obtains the material parameters of the different layers of material samples under different temperatures and strain rates. The different layers of material samples include polyurethane (PU) foam layer material samples, non-woven fabric plus glass fiber composite material layer material samples, sponge layer material samples, and fabric layer material samples. The material parameters include at least one of elastic modulus, Poisson's ratio, and stress-strain curve. Then, an overall sample of the target vehicle roof is acquired, and material tests and simulation benchmarks are performed on the overall sample to verify the accuracy of the obtained material parameters. If accurate, the target vehicle roof is simulated and modeled using the material parameters to obtain the simulation modeling results. Therefore, by simulating and modeling the target vehicle roof using a layered composite material approach, the influence of various materials with different physical properties on the mechanical properties of the roof is fully considered, effectively improving the simulation modeling accuracy and modeling effect.
[0101] Furthermore, this application embodiment also provides a simulation device for a composite material automobile roof, including: a processor, a memory, and a system bus;
[0102] The processor and the memory are connected via the system bus;
[0103] The memory is used to store one or more programs, the one or more programs including instructions that, when executed by the processor, cause the processor to perform any of the above-described implementations of the simulation method for composite material automotive roofs.
[0104] Furthermore, embodiments of this application also provide a computer-readable storage medium storing instructions that, when executed on a terminal device, cause the terminal device to perform any of the above-described implementation methods of the simulation method for composite material car roofs.
[0105] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that all or part of the steps in the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, a server, or a network communication device such as a media gateway, etc.) to execute the methods described in various embodiments or some parts of the embodiments of this application.
[0106] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.
[0107] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus 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 apparatus. 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 apparatus that includes said element.
[0108] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A simulation method of a composite material automobile roof, characterized in that, The method comprises the following steps: acquiring material samples of different layers of a target vehicle roof and acquiring material parameters of the material samples at different temperatures and different strain rates; the material samples of different layers comprise a polyurethane (PU) foam layer material sample, a non-woven fabric and glass fiber composite layer material sample, a sponge layer material sample, and a fabric layer material sample; the material parameters comprise at least one of an elastic modulus, a Poisson's ratio, and a stress-strain curve; acquiring an overall sample of the target vehicle roof and performing material testing and simulation calibration on the overall sample to verify whether the material parameters of the material samples of different layers at different temperatures and different strain rates are accurate; if yes, performing simulation modeling on the target vehicle roof by using the material parameters to obtain a simulation modeling result.
2. The method of claim 1, wherein, The step of acquiring the material parameters of the material samples of different layers at different temperatures and different strain rates comprises the following steps: performing compression testing on the PU foam layer material sample to acquire the material parameters thereof at different temperatures and different strain rates; performing tensile and compression testing on the non-woven fabric and glass fiber composite layer material sample to acquire the material parameters thereof at different temperatures and different strain rates; performing compression testing on the sponge layer material sample to acquire the material parameters thereof at different temperatures and different strain rates; performing orthogonal biaxial tensile testing on the fabric layer material sample to acquire the material parameters thereof at different temperatures and different strain rates.
3. The method of claim 1, wherein, The step of performing tensile and compression testing on the non-woven fabric and glass fiber composite layer material sample to acquire the material parameters thereof at different temperatures and different strain rates comprises the following steps: dividing the non-woven fabric and glass fiber composite layer material sample into K regions by using a stiffness method, and performing tensile and compression testing on sample pieces in the K regions that meet the sample piece requirements to obtain the elastic modulus and the stress-strain curve thereof at different temperatures and different strain rates as the material parameters; K is a positive integer greater than 0.
4. The method of claim 1, wherein, After the step of performing material testing and simulation calibration on the overall sample to verify whether the material parameters of the material samples of different layers at different temperatures and different strain rates are accurate, the method further comprises the following steps: if it is verified that the material parameters of the material samples of different layers at different temperatures and different strain rates are inaccurate, iteratively optimizing the material parameters that do not meet the preset conditions until the preset conditions are met.
5. The method of claim 1, wherein, The step of performing simulation modeling on the target vehicle roof by using the material parameters of the material samples of different layers at different temperatures and different strain rates to obtain a simulation modeling result comprises the following steps: dividing the target vehicle roof into layers and assigning the material parameters of the material samples of different layers at different temperatures and different strain rates to grid units of corresponding material layers; wherein, the PU foam layer and the sponge layer are divided into solid elements, and the non-woven fabric and glass fiber composite layer and the fabric layer are divided into shell elements; establishing connections between different material layers of the target vehicle roof to realize force transmission between the material layers, so that the target vehicle roof is formed as a whole for simulation to obtain a simulation modeling result.
6. The method according to any one of claims 1 to 5, characterized in that, The different temperatures belong to the range of [-35°, 85°]; the different strain rates belong to the range of [0.01 / s, 100 / s].
7. A simulation device for a composite material automobile roof, characterized in that The method comprises the steps of: The first acquisition unit is configured to acquire material samples of different layers on a target vehicle roof and acquire material parameters of the material samples of different layers at different temperatures and different strain rates; the material samples of different layers comprise a polyurethane (PU) foam layer material sample, a non-woven fabric plus glass fiber composite layer material sample, a sponge layer material sample, and a fabric layer material sample; the material parameters comprise at least one of an elastic modulus, a Poisson's ratio, and a stress-strain curve; The second acquisition unit is configured to acquire an overall sample of the target vehicle roof and perform material testing and simulation calibration on the overall sample to verify whether the material parameters of the material samples of different layers at different temperatures and different strain rates are accurate; The simulation unit is configured to, if it is verified that the material parameters of the material samples of different layers at different temperatures and different strain rates are accurate, perform simulation modeling on the target vehicle roof by using the material parameters to obtain a simulation modeling result.
8. The apparatus of claim 7, wherein, The first acquisition unit comprises: The first test subunit is configured to perform compression testing on the PU foam layer material sample to acquire material parameters of the PU foam layer material sample at different temperatures and different strain rates; The second test subunit is configured to perform tensile and compression testing on the non-woven fabric plus glass fiber composite layer material sample to acquire material parameters of the non-woven fabric plus glass fiber composite layer material sample at different temperatures and different strain rates; The third test subunit is configured to perform compression testing on the sponge layer material sample to acquire material parameters of the sponge layer material sample at different temperatures and different strain rates; The fourth test subunit is configured to perform orthogonal biaxial tensile testing on the fabric layer material sample to acquire material parameters of the fabric layer material sample at different temperatures and different strain rates.
9. A simulation device of a composite material automobile roof, characterized by The method comprises the steps of: A processor, a memory, and a system bus; The processor and the memory are connected through the system bus; The memory is configured to store one or more programs, the one or more programs comprising instructions that, when executed by the processor, cause the processor to perform the method of any one of claims 1-6.
10. A computer-readable storage medium, characterized in that, The computer readable storage medium stores instructions, and when the instructions run on the terminal device, the terminal device performs the method of any one of claims 1-6.