A design method for carbon fiber reinforced composite materials based on finite element analysis

Abstract

The present invention relates to the technical field of computer-aided engineering design, and discloses a design method for carbon fiber reinforced composite materials based on finite element analysis, including: constructing a finite element model of carbon fiber reinforced composite materials, randomly generating a mixing ratio scheme of carbon fiber and matrix, generating constraint conditions of the mixing ratio scheme based on the design parameters of the finite element model, generating the axial tensile strength of carbon fiber reinforced composite materials based on the mixing ratio scheme, generating the damage variable of carbon fiber reinforced composite materials based on the finite element model and the mixing ratio scheme, generating the damage limit tensile force of carbon fiber reinforced composite materials based on the axial tensile strength, damage variable and constraint conditions, improving the dynamic response prediction accuracy by introducing a temperature change rate parameter, considering the influence of the damage limit tensile force and temperature change rate on the real-time strength of carbon fiber reinforced composite materials, and being able to more accurately reflect the strength performance of the material under actual working conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of computer-aided engineering design, and particularly to a design method for carbon fiber reinforced composite materials based on finite element analysis. Background Art

[0002] Due to its excellent properties such as high specific strength, high specific modulus, and corrosion resistance, carbon fiber reinforced composite materials have been widely used in the fields of aerospace, automotive, sports equipment, etc. However, the performance of carbon fiber reinforced composite materials is affected by various factors such as fiber orientation, ply sequence, and fiber volume fraction, and its design process is relatively complex.

[0003] Traditional design of carbon fiber reinforced composite materials mainly relies on actual testing of material properties (such as tensile, compression, hygrothermal aging, etc.), depends on manual experience, requires a large amount of trial and error, lacks efficient data analysis models and algorithms, not only leads to high costs and long R & D cycles, but also is difficult to fully explore the performance potential of materials. With the development of computer technology, the finite element analysis method has gradually been applied to the field of composite material design. However, the finite element model has significant defects in simulating the damage evolution law and temperature effect of materials. The finite element model cannot accurately simulate the damage evolution law under complex environments (such as high temperature), and the coupling effect between fiber fracture and matrix cracking is not fully considered, resulting in insufficient accuracy of its performance prediction and incomplete design results. Summary of the Invention

[0004] The present invention provides a design method for carbon fiber reinforced composite materials based on finite element analysis, and its main purpose is to solve the problems that the finite element model cannot accurately simulate the damage evolution law under complex environments (such as high temperature), the coupling effect between fiber fracture and matrix cracking is not fully considered, resulting in insufficient accuracy of its performance prediction and incomplete design results.

[0005] To achieve the above object, a design method for carbon fiber reinforced composite materials based on finite element analysis provided by the present invention includes:

[0006] S1: Construct a finite element model of carbon fiber reinforced composite materials;

[0007] S2: Randomly generate a mixing ratio scheme of carbon fiber and matrix;

[0008] S3: Generate constraint conditions of the mixing ratio scheme based on the design parameters of the finite element model;

[0009] S4: Generate the axial tensile strength of the carbon fiber reinforced composite material based on the mixing ratio scheme, and the calculation formula of the axial tensile strength is:

[0010]

[0011] In the formula: is the axial tensile strength, is the tensile strength of carbon fiber, is the tensile strength of the matrix, is the volume fraction of carbon fiber, is the volume fraction of the matrix, is the contribution of carbon fiber to the axial tensile strength of the composite material, is the contribution of the matrix material to the axial tensile strength of the composite material;

[0012] S5: Generate the damage variable of the carbon fiber reinforced composite material based on the finite element model and the mixing ratio scheme,

[0013]

[0014] In the formula: is the current axial strain, is the axial strain at damage initiation, is the axial strain at fiber fracture, is the damage variable;

[0015] S6: Generate the damage limit tensile force of the carbon fiber reinforced composite material based on the axial tensile strength, the damage variable and the constraint conditions,

[0016]

[0017] In the formula: is the damage variable, is the axial tensile strength, is the damage limit tensile force, is the current axial strain, is the axial strain at damage initiation, is the axial strain at fiber fracture, is the volume fraction of carbon fiber, is the volume fraction of the matrix, is the tensile strength of carbon fiber, is the tensile strength of the matrix;

[0018] S7: Generate the real-time strength of the carbon fiber reinforced composite material based on a preset mixing algorithm, the damage limit tensile force and the temperature change of the carbon fiber reinforced composite material, where the mixing algorithm is:

[0019]

[0020] In the formula: is the real-time strength, is the damage limit tensile force, is the tensile strength value of carbon fiber at the maximum temperature, is the real-time temperature, is the reference temperature, is the reference temperature the maximum tensile strength value of carbon fiber at the reference temperature is the thermal stability coefficient of carbon fiber, is the tensile strength value of carbon fiber at the maximum temperature, is the temperature change;

[0021] S8: Sort the real-time strength to obtain the strength sequence of the carbon fiber reinforced composite material, and generate the carbon fiber reinforced composite material according to the target mixing ratio determined by the strength sequence.

[0022] Optionally, the design parameters of the finite element model include:

[0023] is the current axial strain, is the axial strain at the onset of damage, is the axial strain at fiber fracture, is the carbon fiber volume fraction, is the matrix volume fraction, is the tensile strength of carbon fiber, is the tensile strength of the matrix.

[0024] Optionally, the scheme for randomly generating the mixing ratio of carbon fiber and matrix includes:

[0025] Randomly generate a number between 0 and 1 as the carbon fiber volume fraction;

[0026] Calculate the matrix volume fraction in the carbon fiber reinforced composite material according to the carbon fiber volume fraction, where the calculation formula for the matrix volume fraction is as follows:

[0027]

[0028] In the formula: is the carbon fiber volume fraction, is the matrix volume fraction;

[0029] Determine the mixing ratio scheme of carbon fiber and matrix based on the carbon fiber volume fraction and the matrix volume fraction.

[0030] Optionally, the constraint condition is:

[0031]

[0032] In the formula: is the current axial strain, is the axial strain at the onset of damage, is the axial strain at fiber breakage, is the carbon fiber volume fraction, is the matrix volume fraction.

[0033] Optionally, the constraint condition further includes: the real-time strength is within a preset predicted tensile force range.

[0034] Optionally, the sorting of the real-time strength to obtain the strength sequence of the carbon fiber reinforced composite material includes: determining the array to be sorted of the real-time strength;

[0035] Performing a descending sort on the array to be sorted to obtain an ordered array of the real-time strength;

[0036] Performing data screening on the ordered array according to a preset predicted tensile force range to obtain the strength sequence within the predicted tensile force range.

[0037] Optionally, generating the carbon fiber reinforced composite material according to the target mixing ratio determined based on the strength sequence includes:

[0038] Screening out the target mixing ratio in the mixing ratio scheme according to the sorted real-time strength;

[0039] Synthesizing the carbon fiber and the matrix based on the target mixing ratio to obtain the carbon fiber reinforced composite material.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] Through the calculation formula of the real-time strength, by inputting multiple groups of carbon fiber volume fractions and matrix volume fractions into the calculation formula of the real-time strength, different real-time strengths are obtained, and then the real-time strengths of carbon fiber composite materials with different specifications at a certain temperature are analyzed, the most suitable carbon fiber volume fraction and matrix volume fraction at a certain temperature condition are obtained, by adjusting the temperature change amount, the influence of temperature on the carbon fiber volume fraction and matrix volume fraction with different ratios is analyzed, by introducing the temperature change amount parameter, the dynamic response prediction accuracy is improved, considering the influence of the damage limit tensile force and the temperature change amount on the real-time strength of the carbon fiber reinforced composite material, it can more accurately reflect the strength performance of the material under actual working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a schematic flowchart of a design method for a carbon fiber reinforced composite material based on finite element analysis provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0044] The terms used in the embodiments of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The singular forms "the" and "said" used in the embodiments of the present invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. "Plurality" generally includes at least two.

[0045] Depending on the context, the words "if" or "when" as used herein may be interpreted as "when" or "while" or "in response to determining" or "in response to detecting". Similarly, depending on the context, the phrase "if determined" or "if detecting (stated condition or event)" may be interpreted as "when determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)".

[0046] The embodiments of the present application provide a design method for carbon fiber reinforced composite materials based on finite element analysis. The execution subject of the design method for carbon fiber reinforced composite materials based on finite element analysis includes, but is not limited to, at least one of electronic devices such as a server, a terminal, etc. that can be configured to execute the method provided in the embodiments of the present application. In other words, the design method for carbon fiber reinforced composite materials based on finite element analysis can be executed by software or hardware installed on a terminal device or a server device. The server includes, but is not limited to: a single server, a server cluster, a cloud server, or a cloud server cluster, etc. The server can be an independent server or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, Content Delivery Network (CDN), and big data and artificial intelligence platforms.

[0047] As Figure 1 shown, it is a schematic flowchart of a design method for carbon fiber reinforced composite materials based on finite element analysis of the present invention. In this embodiment, the design method for carbon fiber reinforced composite materials based on finite element analysis includes:

[0048] S1: Construct a finite element model of the carbon fiber reinforced composite material.

[0049] In the embodiments of the present invention, the design parameters of the finite element model include:

[0050] is the current axial strain, is the axial strain at damage initiation, is the axial strain at fiber fracture, is the carbon fiber volume fraction, is the matrix volume fraction, is the tensile strength of the carbon fiber, is the tensile strength of the matrix.

[0051] Specifically, first, feature screening and simplification are carried out to retain key features. According to the load transfer path, the main structures are retained, such as the laminate edge, stiffening structure, connection holes, etc. Chamfers, bosses, non-load-bearing small holes with a size <0.5 mm are removed to reduce the computational complexity. Use CATIA, SolidWorks or ABAQUS / CAE to draw a three-dimensional solid or surface model, ensuring surface continuity (curvature radius > 1 mm). Before importing an external model (such as an STL file), geometric cleaning tools (such as GeomCleanup in HyperMesh) are required to repair broken surfaces, short edges, etc.

[0052] Specifically, when performing the import operation, the coordinate system needs to be determined. First, define the global coordinate system settings. Usually, the geometric center of the model or the load application point (such as the symmetry center of the laminate) is selected. The directions of the coordinate axes must include: X-axis: along the main fiber direction (such as the fiber direction of the 0° ply), Y-axis: perpendicular to the fiber direction (within the laminate plane), Z-axis: perpendicular to the laminate plane (thickness direction). Then, local material coordinate systems are assigned. One axis of each layer's material coordinate system is aligned with the fiber direction (such as the fiber direction of the ±45° ply makes an angle of ±45° with the X-axis). If there are stiffeners or complex connections, the fiber direction needs to be adjusted in the local coordinate system to match the actual ply.

[0053] After completing the above operations, ply design and cross-section definition need to be carried out. First, the ply sequence needs to be defined according to the actual process. The single-layer thickness is usually , and then the carbon fiber volume fraction is determined. Through the carbon fiber volume fraction (such as ), the matrix volume fraction ( ) is calculated, and then the equivalent densities of the carbon fiber and the matrix are calculated, so as to obtain the tensile strength of the carbon fiber and the tensile strength of the matrix.

[0054] S2: Randomly generate a mixing ratio scheme of carbon fiber and matrix.

[0055] In the embodiments of the present invention, the randomly generating a mixing ratio scheme of carbon fiber and matrix includes:

[0056] Randomly generate a number between 0 and 1 as the carbon fiber volume fraction;

[0057] Calculate the matrix volume fraction in the carbon fiber reinforced composite according to the carbon fiber volume fraction, where the calculation formula for the matrix volume fraction is as follows:

[0058]

[0059] In the formula: is the carbon fiber volume fraction, is the matrix volume fraction;

[0060] Determine the mixing ratio scheme of the carbon fiber and the matrix based on the carbon fiber volume fraction and the matrix volume fraction.

[0061] Specifically, first determine the mixing ratio range. The carbon fiber volume fraction is usually set in the range of 30% - 70%. The calculation formula for the matrix volume fraction is 100% - the carbon fiber volume fraction. Example: If the carbon fiber volume fraction = 50%, then the matrix volume fraction = 50%;

[0062] Use a uniform distribution random number generator (0 - 100) to generate the mixing ratio scheme:

[0063] Step 1: Set the seed value to ensure reproducibility (e.g., seed = 20250310) and generate 10 sets of independent random numbers as candidate carbon fiber volume fraction values.

[0064] Step 2: Check whether the carbon fiber volume fraction is within the range of 30% - 70%, and exclude the outliers outside the range (e.g., if the generated value < 30%, regenerate).

[0065] Specifically, randomly generating the ratio scheme can help researchers explore carbon fiber and matrix combinations that have not been considered before, thereby discovering new performance characteristics or performance improvement points. Through randomness, a large number of different ratio schemes can be generated, and these schemes together constitute a vast design space from which the optimal or sub - optimal designs can be screened. Among a large number of randomly generated schemes, there may be certain ratio combinations that can significantly improve the performance of the composite material. Through screening, one or more more cost - effective carbon fiber and matrix combinations may be found, thereby reducing the production cost while ensuring the performance.

[0066] S3: Generate the constraint conditions for the mixing ratio scheme based on the design parameters of the finite element model.

[0067] In the embodiment of the present invention, the constraint conditions are:

[0068]

[0069] In the formula: is the current axial strain, is the axial strain at damage initiation, is the axial strain at fiber fracture, is the volume fraction of carbon fiber, is the volume fraction of matrix.

[0070] Specifically, the current axial strain means the strain value actually borne by the carbon fiber reinforced composite material, the axial strain at damage initiation means the strain when microcracks or matrix cracking first occur in the carbon fiber reinforced composite material, the axial strain at fiber fracture means the ultimate strain when the carbon fiber reinforced composite material completely fails, the volume fraction of carbon fiber means the volume percentage of carbon fiber in the carbon fiber reinforced composite material, and the volume fraction of matrix means the volume percentage of matrix in the carbon fiber reinforced composite material.

[0071] S4: Generate the axial tensile strength of the carbon fiber reinforced composite material based on the mixing ratio scheme.

[0072] In an embodiment of the present invention, the calculation formula for the axial tensile strength is:

[0073]

[0074] In the formula: is the axial tensile strength, is the tensile strength of the carbon fiber, is the tensile strength of the matrix, is the volume fraction of carbon fiber, is the volume fraction of matrix, is the contribution of carbon fiber to the axial tensile strength of the composite material, is the contribution of the matrix material to the axial tensile strength of the composite material;

[0075] Specifically, the formula shows that the total strength of the carbon fiber composite material is the superposition of the contributions of the fiber and the matrix.

[0076] S5: Generate the damage variable of the carbon fiber reinforced composite material based on the finite element model and the mixing ratio scheme.

[0077] In an embodiment of the present invention, the calculation formula for the damage variable is:

[0078]

[0079] In the formula: is the current axial strain, is the axial strain at damage initiation, is the axial strain at fiber fracture, is the damage variable.

[0080] In detail, the current axial strain represents the actual deformation of the material under axial load, which is obtained through experimental testing or finite element calculation, reflects the current stress state of the CFRP, and is the driving parameter of damage evolution.

[0081] In detail, the damage initiation axial strain represents the critical strain value when the carbon fiber reinforced composite material begins to show micro damage (such as fiber micro cracks and matrix cracking). It is predicted through tensile tests or theoretical models based on the fatigue life of materials, marking the turning point of the carbon fiber reinforced composite material from the elastic deformation stage to the damage accumulation stage.

[0082] In detail, the axial strain at fiber fracture indicates the maximum strain value when the carbon fiber reinforced composite material is completely fractured, which corresponds to the ultimate bearing capacity of the material. When the carbon fiber reinforced composite material is subjected to external force until the critical point of complete fracture, the strain value of its fiber along the force direction (i.e. axial direction) occurs. This strain value is actually a quantitative description of the deformation capacity of the material under the limit state, which is directly related to the maximum deformation degree that the composite material can achieve when subjected to external force.

[0083] More importantly, the axial strain at fiber fracture is closely related to the ultimate bearing capacity of the material. In composite materials, carbon fiber, as a reinforcing phase, undertakes the main load transfer task. When the external force gradually increases to a certain critical value, the carbon fiber will begin to fracture, and the corresponding axial strain at this time is the ultimate strain of the material. This ultimate strain value not only reflects the maximum deformation that the material can withstand before fracture, but also indirectly reflects the ultimate bearing capacity of the material - that is, the maximum external force that the material can withstand before fracture.

[0084] Therefore, for carbon fiber reinforced composite materials, the axial strain at fiber fracture is an important indicator to measure its mechanical properties, especially its load-bearing capacity. At the same time, this parameter also provides an important data basis for the reliability assessment, safety analysis and service life prediction of composite materials.

[0085] In detail, the damage variable shows a linear growth with strain, reflecting the progressive process of CFRP fracture and matrix damage. The formula adopts the linear damage evolution assumption and is applicable to the brittle fracture behavior dominated by CFRP.

[0086] S6: generating a damage limit tensile force of the carbon fiber reinforced composite material based on the axial tensile strength, the damage variable and the constraint condition.

[0087] In the embodiment of the present invention, the damage limit tensile force calculation formula is:

[0088]

[0089] Where: is the damage variable, is the axial tensile strength, is the damage limit tensile force, is the current axial strain, is the damage initiation axial strain, is the axial strain at fiber rupture, is the carbon fiber volume fraction, is the matrix volume fraction, is the tensile strength of carbon fiber, is the tensile strength of the matrix.

[0090] In detail, by inputting a large amount of data, tensile tests are carried out on different batches of carbon fiber reinforced composites, and various strain data during the experiment and information such as the final breaking strength are recorded. By collecting a large amount of experimental data, the statistical reliability of the results can be significantly improved. A large sample size can reduce the impact of accidental errors and make the experimental results closer to the actual situation. Through data analysis, the key factors affecting material properties can be discovered, thereby guiding material improvements and optimization of production processes. At the same time, a large amount of experimental data is an important input for machine learning and predictive models. By establishing a data-based model, the performance of CFRP under different conditions can be predicted, providing strong support for design and production.

[0091] In detail, the finite element software is used to simulate and analyze the carbon fiber reinforced composite structure to obtain stress and strain data under different working conditions. At the same time, after the data is input, it is necessary to organize and clean the data, check the integrity of the data, and remove missing values ​​or abnormal values. For example, if the damage variable of a sample is greater than 1 or less than 0, then the data may be wrong and needs to be corrected or eliminated.

[0092] Sorting and cleaning data can ensure the accuracy and consistency of the data and reduce analytical biases caused by data errors or inconsistencies. The cleaned data is purer and can more accurately reflect the true performance of carbon fiber reinforced composites, thereby improving the reliability of the analysis results. At the same time, through data cleaning, invalid or low-quality data can be identified and eliminated, thereby avoiding wasting computing resources and time in subsequent analysis. Cleaned data helps to build a more robust and accurate prediction model, improve the generalization ability and prediction accuracy of the model, and eliminate missing values ​​and outliers. It can reduce errors in the analysis process and make the prediction results of statistical analysis and machine learning models more accurate.

[0093] Specifically, statistical analysis is performed on the calculated damage limit tensile force, and histograms, box plots, etc. are plotted to understand the data distribution. For example, check whether there is an obvious central tendency or a large degree of dispersion. Histograms and box plots can visually display the data distribution pattern, including the central tendency (such as the mean or median) and the degree of dispersion (such as the standard deviation or interquartile range). Through the box plot, it is easy to identify outliers or extreme values in the data, which may have a significant impact on the statistical analysis results and need to be excluded.

[0094] Secondly, histograms and box plots help to evaluate whether the damage limit tensile force data obtained under different batches or different conditions are consistent, thereby judging the stability and reliability of the production process. By comparing the histograms and box plots under different conditions, the performance differences of carbon fiber reinforced composites under different batches, different formulations or different production processes can be visually compared.

[0095] After understanding the data distribution, it is possible to more targeted select useful information in the data. Based on the statistical analysis results and visualization charts, the material design can be formulated more scientifically, improving the accuracy and effectiveness of decision-making.

[0096] The methods of statistical analysis include:

[0097] Step 1: Correlation analysis, analyze the correlation between the damage limit tensile force and other parameters (such as carbon fiber volume fraction, damage variable, etc.). Methods such as the Pearson correlation coefficient can be used for calculation. If a strong positive correlation is found, it indicates that increasing the carbon fiber volume fraction helps to increase the damage limit tensile force. By calculating the Pearson correlation coefficient, the strength and direction of the linear relationship between the damage limit tensile force and parameters such as carbon fiber volume fraction and damage variable can be quantified. A positive correlation means that an increase in one parameter is accompanied by an increase in another parameter, while a negative correlation means that an increase in one parameter is accompanied by a decrease in another parameter. If the analysis results show a strong positive correlation between the carbon fiber volume fraction and the damage limit tensile force, then this can provide clear guidance for material design, that is, increasing the carbon fiber volume fraction within a certain range is expected to increase the damage limit tensile force of the material.

[0098] After understanding the correlation between parameters, the performance of the material can be predicted and optimized by adjusting these parameters. For example, in the design of carbon fiber reinforced composites, according to the relationship between the carbon fiber volume fraction and the damage limit tensile force, the carbon fiber content can be adjusted to achieve the required mechanical properties. Correlation analysis can also help to identify the key factors affecting the material performance, thereby formulating more effective quality control strategies. By monitoring these key factors, it is possible to ensure that the produced materials have consistent performance.

[0099] Step 2: Comparative analysis, compare the calculated results with the design requirements or previous experimental data. If the calculated damage limit tensile force is lower than the design requirements, further analysis of the reasons is required, which may be due to poor material performance, process problems, or unreasonable design parameters. By comparing the calculation results with the design requirements, the rationality of the design can be verified. If the calculation results meet or exceed the design requirements, it means that the design parameters and material selection are reasonable, and subsequent production and application can be further promoted, and problems can be discovered and solved in a timely manner. If the calculated damage limit tensile force is lower than the design requirements, this means that the product may not meet the predetermined performance standards. At this time, timely discovery of problems and in-depth analysis can avoid waste and potential quality problems in subsequent production.

[0100] At the same time, the comparison results can reflect the gap between the actual performance of the material and the design expectations. If the material performance is not good, it may be necessary to replace the material or adjust the material formula to increase the damage limit tensile force. Moreover, through comparative analysis, the weak links in the process can be identified and targeted improvements can be made, such as optimizing production process parameters and improving production accuracy.

[0101] Unreasonable design parameters may also lead to substandard calculation results. At this time, according to the results of comparative analysis, the design parameters are adjusted, such as changing the volume fraction of carbon fiber, optimizing the ply structure, etc., to improve the mechanical properties of the material. In the process of comparative analysis, some new phenomena or laws may be discovered, which will help promote the innovation and development of materials science and engineering technology.

[0102] Step 3: Feedback on the design and optimization of material selection. For example, when the carbon fiber volume fraction increases to a certain level, the damage limit tensile force does not increase significantly, and it may be necessary to find a higher strength carbon fiber material, or to redistribute a more appropriate carbon fiber volume fraction and matrix volume fraction.

[0103] The damage limit tensile force calculation formula can directly reflect the maximum limit tensile force of various carbon fiber reinforced composite materials and is applicable to carbon fiber reinforced composite materials of different specifications.

[0104] S7: Based on a preset hybrid algorithm, the damage limit tension and the temperature change of the carbon fiber reinforced composite material, generating the real-time strength of the carbon fiber reinforced composite material, wherein the hybrid algorithm is.

[0105]

[0106] Where: is the real-time intensity, is the damage limit tensile force, It is the tensile strength of carbon fiber at the maximum temperature. is the real-time temperature, is the reference temperature, is the reference temperature the maximum tensile force value of carbon fiber at is the thermal stability coefficient of carbon fiber, is the tensile force value that carbon fiber can withstand at the maximum temperature, is the temperature change amount, which refers to the difference between the real-time temperature and the reference temperature.

[0107] Specifically, by considering the test of the temperature change amount, it can ensure that the carbon fiber reinforced composite material has higher reliability in actual applications. This helps to reduce failures and accidents caused by the material properties not meeting expectations. The mechanical properties of carbon fiber reinforced composite materials are significantly affected by temperature. By considering the temperature change amount, the stress situation of the material in actual applications can be more accurately simulated, thereby improving the accuracy of the test.

[0108] In the embodiment of the present invention, the constraint condition further includes: the real-time strength is within a preset predicted tensile force range.

[0109] Specifically, the tensile force value that carbon fiber can withstand at the maximum temperature is the maximum tensile force of a certain carbon fiber reinforced composite material.

[0110] The thermal stability coefficient of carbon fiber characterizes the mechanical property stability of carbon fiber materials in the temperature field change, specifically reflecting the ability of the material to maintain its initial tensile strength in a high-temperature environment. Experimental data show that when the temperature exceeds the glass transition temperature, the interfacial bonding strength between carbon fiber and the resin matrix will decay exponentially with a proportionality coefficient.

[0111] At the same time, the thermal stability coefficients of carbon fibers in different carbon fiber reinforced composite materials are different and will change with the change of the ratio of the carbon fiber volume fraction to the matrix volume fraction. At this time, the damage limit tensile force will also change accordingly.

[0112] By correlating the tensile force value that carbon fiber can withstand at the maximum temperature with the damage limit tensile force, the real-time strength of carbon fiber composite materials with different specifications at a certain temperature is obtained. By inputting multiple groups of data, multiple groups of real-time strength are obtained, and then the most suitable carbon fiber volume fraction and matrix volume fraction under a certain temperature condition are analyzed.

[0113] This formula takes into account the influence of the damage limit tensile force and the temperature change amount on the real-time strength of carbon fiber reinforced composite materials, and can more accurately reflect the strength performance of the materials under actual working conditions.

[0114] S8: Sort the real-time strength to obtain the strength sequence of the carbon fiber reinforced composite material, and generate the carbon fiber reinforced composite material according to the target mixing ratio determined by the strength sequence.

[0115] In the embodiments of the present invention, the sorting of the real-time strength to obtain the strength sequence of the carbon fiber reinforced composite material includes:

[0116] Determine the array to be sorted of the real-time strength;

[0117] Perform a descending sort on the array to be sorted to obtain the ordered array of the real-time strength;

[0118] Perform data screening on the ordered array according to a preset predicted tensile force range to obtain the strength sequence within the predicted tensile force range.

[0119] Specifically, the array to be sorted means the unsorted real-time strength array, the ordered array means the sorted real-time strength array, and the predicted tensile force range pair means the force range set in advance, which is used to obtain a qualified strength sequence.

[0120] Specifically, the expression formula is; ~ , where = ;

[0121] In the formula: represents a uniform distribution on the interval , meaning that has an equal possibility of taking any value within the interval ;

[0122] Based on obtain the carbon fiber volume fraction and the matrix volume fraction.

[0123] In the embodiments of the present invention, the generation of the carbon fiber reinforced composite material according to the target mixing ratio determined based on the strength sequence includes:

[0124] Screen out the target mixing ratio in the mixing ratio scheme according to the sorted real-time strength;

[0125] Based on the target mixing ratio, synthesize the carbon fiber and the matrix to obtain the carbon fiber reinforced composite material.

[0126] Specifically, let the array to be sorted be ,

[0127] For each round i , j ( )

[0128] After N rounds of sorting, the first N elements of the array are already ordered (in descending order), obtaining the ordered array ;

[0129] For adjacent elements in the array to be sorted and Compare with it. When happens, then swap 's value. The swap operation can be expressed as:

[0130]

[0131] In the formula: is the array to be sorted, is the real-time strength to be sorted within the predicted tensile force range , , is the sorted within the predicted tensile force range, and t is a temporary variable.

[0132] In several embodiments provided by the present invention, it should be understood that the disclosed methods and systems can be implemented in other ways. For example, the system embodiments described above are only illustrative. For example, the division of the modules is only a logical function division, and there can be other division methods in actual implementation.

[0133] The modules described as separate components may or may not be physically separated. The components shown as modules may or may not be physical units, that is, they can be located in one place, or they can be distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0134] In addition, in each embodiment of the present invention, the functional modules can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above integrated units can be implemented in the form of hardware, or in the form of a combination of hardware and software functional modules.

[0135] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention.

[0136] The embodiments of this application can acquire and process relevant data based on artificial intelligence technology. Among them, artificial intelligence is the theory, method, technology and application system that uses a digital computer or a machine controlled by a digital computer to simulate, extend and expand human intelligence, perceive the environment, acquire knowledge and use knowledge to obtain the best results.

[0137] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A design method for carbon fiber reinforced composite materials based on finite element analysis, characterized in that, Including: S1: Construct a finite element model of carbon fiber reinforced composite material; S2: Randomly generate a mixing ratio scheme of carbon fiber and matrix; S3: Generate constraint conditions of the mixing ratio scheme based on the design parameters of the finite element model; S4: Generate the axial tensile strength of the carbon fiber reinforced composite material based on the mixing ratio scheme, and the calculation formula of the axial tensile strength is: In the formula: is the axial tensile strength, is the tensile strength of carbon fiber, is the tensile strength of the matrix, is the volume fraction of carbon fiber, is the volume fraction of the matrix, is the contribution of carbon fiber to the axial tensile strength of the composite material, is the contribution of the matrix material to the axial tensile strength of the composite material; S5: Generate the damage variable of the carbon fiber reinforced composite material based on the finite element model and the mixing ratio scheme, and the calculation formula of the damage variable is: In the formula: is the current axial strain, is the axial strain at damage initiation, is the axial strain at fiber fracture, is the damage variable; S6: Generate the damage limit tensile force of the carbon fiber reinforced composite material based on the axial tensile strength, the damage variable and the constraint conditions, and the calculation formula of the damage limit tensile force is: In the formula: is the damage variable, is the axial tensile strength, is the damage limit tensile force, is the current axial strain, is the axial strain at the initiation of damage, is the axial strain at fiber fracture, is the volume fraction of carbon fiber, is the volume fraction of matrix, is the tensile strength of carbon fiber, is the tensile strength of the matrix; S7: Generate the real-time strength of the carbon fiber reinforced composite material based on a preset mixing algorithm, the damage limit tensile force and the temperature change of the carbon fiber reinforced composite material, wherein the mixing algorithm is: In the formula: is the real-time strength, is the damage limit tensile force, is the tensile force value that carbon fiber can withstand at the maximum temperature, is the real-time temperature, is the reference temperature, is the reference temperature the maximum tensile force value that carbon fiber can withstand at this time, is the thermal stability coefficient of carbon fiber, is the tensile force value that carbon fiber can withstand at the maximum temperature, is the temperature change; S8: Sort the real-time strength to obtain a strength sequence of the carbon fiber reinforced composite material, and generate the carbon fiber reinforced composite material according to the target mixing ratio determined by the strength sequence.

2. The design method of carbon fiber reinforced composite materials based on finite element analysis according to claim 1, characterized in that The design parameters of the finite element model include: is the current axial strain, is the axial strain at damage initiation, is the axial strain at fiber fracture, is the volume fraction of carbon fiber, is the volume fraction of matrix, is the tensile strength of carbon fiber, is the tensile strength of matrix.

3. The design method of carbon fiber reinforced composite material based on finite element analysis according to claim 2, characterized in that, The randomly generated mixing ratio scheme of carbon fiber and matrix includes: Randomly generate a number between 0 and 1 as the carbon fiber volume fraction; Calculate the matrix volume fraction in the carbon fiber reinforced composite material according to the carbon fiber volume fraction, wherein: the calculation formula of the matrix volume fraction is as follows: In the formula: is the volume fraction of carbon fiber, is the volume fraction of the matrix; Determine the mixing ratio scheme of carbon fiber and matrix based on the carbon fiber volume fraction and the matrix volume fraction.

4. The design method of carbon fiber reinforced composite material based on finite element analysis according to claim 2, characterized in that, The constraint conditions are: In the formula: is the current axial strain, is the axial strain at damage initiation, is the axial strain at fiber fracture, is the volume fraction of carbon fiber, is the volume fraction of matrix.

5. The design method of carbon fiber reinforced composite material based on finite element analysis according to claim 4, characterized in that, The constraint conditions also include: the real-time strength is within a preset predicted tensile force range.

6. The method for designing a carbon fiber reinforced composite material based on finite element analysis according to claim 1, characterized in that The sorting of the real-time strength to obtain a strength sequence of the carbon fiber reinforced composite material includes: determining an array to be sorted of the real-time strength; Perform a descending sort on the array to be sorted to obtain an ordered array of the real-time strength; Perform data screening on the ordered array according to a preset predicted tensile force range to obtain a strength sequence within the predicted tensile force range.

7. The design method of carbon fiber reinforced composite material based on finite element analysis according to claim 6, characterized in that, The generating of the carbon fiber reinforced composite material according to the target mixing ratio determined by the strength sequence includes: Screen out the target mixing ratio in the mixing ratio scheme according to the sorted real-time strength; Synthesize the carbon fiber and the matrix based on the target mixing ratio to obtain the carbon fiber reinforced composite material.

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