A simulation method for composite materials based on acoustic emission

Abstract

A simulation method for composite materials based on acoustic emission, which relates to a simulation method for composite materials. The present invention aims to solve the problem that existing simulation methods cannot accurately simulate various damage types that occur in reality, and this limitation can lead to misunderstandings of material properties and inaccurate predictions. The present invention proposes a simulation method based on acoustic emission, which can more accurately distinguish and simulate the true damage modes in fiber bundles and between layers in composite materials. This new method takes into account matrix damage and interface damage in unidirectional damage of fiber bundles, as well as interface damage and fiber damage in bi- and tri-directional damage. In addition, it can more accurately analyze interlayer damage, distinguish matrix damage, fiber / matrix debonding damage, and fiber damage. The present invention belongs to the technical field of composite materials.

Description

Technical Field

[0001] The present invention relates to a simulation method for composite materials, belonging to the technical field of composite materials. Background Art

[0002] In the existing simulation methods for composite materials, for the failure criterion of fiber bundles, generally, the first direction is considered as fiber damage, and the second and third directions are considered as matrix damage; while in actual fiber bundles, the damage in the first direction also includes matrix damage and fiber / matrix interface damage, and the damage in the second and third directions actually also includes fiber / matrix interface damage and a small amount of fiber damage; for interlaminar damage, no distinction is made in the simulation, and the actual interlaminar damage is also a combination of matrix damage, fiber / matrix debonding damage, and a small amount of fiber damage.

[0003] The damage process of composite materials is very complex, and it is difficult to distinguish the co-occurrence of multiple damage modes; in traditional mesoscopic simulation analysis methods, the damage in the first direction of fiber bundles is usually regarded as fiber damage, while the damage in the second and third directions is considered as matrix damage; although this classification method helps to understand the damage mechanism of materials to a certain extent, it ignores more complex microscopic damage phenomena, such as the interface damage between fibers and the matrix.

[0004] Although the existing simulation methods help to predict and evaluate the performance of composite materials to a certain extent, they usually cannot accurately simulate various damage types that occur in practice. Especially in the analysis of interlaminar damage, the existing methods often do not distinguish different types of damage, such as matrix damage, fiber / matrix debonding damage, and fiber damage; the limitations of this method may lead to misunderstandings of material properties and inaccurate predictions. Summary of the Invention

[0005] In order to solve the problem that the existing simulation methods cannot accurately simulate various damage types that occur in practice, and this limitation will lead to misunderstandings of material properties and inaccurate predictions, the present invention further provides a simulation method for composite materials based on acoustic emission.

[0006] The technical solution adopted by the present invention to solve the above problems is: the steps of the present invention include:

[0007] Step 1: Conduct a tensile experiment to determine the characteristic parameters of acoustic emission signals corresponding to damage modes.

[0008] Step 2: Use acoustic emission technology to conduct a tensile experiment, and perform clustering analysis on the AE data to identify different damage modes in the tensile experiment. Calculate the proportion of different damage modes based on the impact numbers of various damage modes. This proportion is the microscopic damage composition. At the same time, design tensile experiments with different fiber volume fractions to obtain the relationship between the proportion of damage modes and the fiber volume fraction.

[0009] Step 3: Design specific working condition experiments for the fabric based on AE technology, analyze the AE data through clustering methods, and calculate the distribution of each damage mode in the experimental results based on the number of impacts. The specific working conditions include tension, compression, and shear;

[0010] Step 4: Establish a mesoscopic unit cell simulation model of the fabric, apply boundary conditions according to specific working conditions for calculation, and extract the number of damages. The specific working conditions include tension, compression, and shear;

[0011] Step 5: Calculate the fiber bundle volume fraction of the fabric composite used in the experiment through metallographic inspection, and combine the relationship between the damage mode proportion obtained in Step 2 and the fiber volume fraction to determine the damage proportion input of fiber bundles and interlayer damages in subsequent simulations;

[0012] Step 6: According to the damage proportion, classify the complex damage modes obtained from the fabric specific working condition simulation into matrix damage, fiber / matrix debonding damage, and fiber damage. The specific working conditions include tension, compression, and shear;

[0013] Step 7: Compare with the experimental results to verify the simulation results.

[0014] Further, the tension experiments in Step 1 include pure resin tension experiments, 45° unidirectional tape tension experiments, interlayer tension experiments, and 0° unidirectional tape tension experiments.

[0015] Further, the damage modes in Step 1 include matrix cracking damage mode, fiber / matrix debonding damage mode, and fiber fracture damage mode.

[0016] Further, Step 2 specifically includes:

[0017] Step 201: Use acoustic emission technology to conduct tension experiments on 0° unidirectional tapes, perform clustering analysis on the AE data to identify different damage modes in the 0° unidirectional tape tension experiments, calculate the proportion of different damage modes based on the number of impacts of each damage mode. This proportion is the microscopic damage composition of the damage in one direction of the fiber bundle. At the same time, conduct tension experiments on 0° unidirectional tapes with different volume fractions to obtain the relationship between the proportion of different damage modes and the fiber volume fraction;

[0018] Step 202: Use acoustic emission technology to conduct tension experiments on 90° unidirectional tapes, perform clustering analysis on the AE data to identify different damage modes in the 90° unidirectional tape tension experiments, calculate the proportion of different damage modes based on the number of impacts of each damage mode. This proportion is the microscopic damage composition of the damage in the second and third directions of the fiber bundle. At the same time, conduct tension experiments on 90° unidirectional tapes with different volume fractions to obtain the relationship between the proportion of different damage modes and the fiber volume fraction;

[0019] Step 203: Conduct an interlayer tensile experiment on the fabric using acoustic emission technology, perform cluster analysis on the AE data to identify different damage modes in the interlayer tensile experiment of the fabric, and calculate the proportion of different damage modes based on the impact numbers of each damage mode. This proportion is the microscopic damage composition of the interlayer damage of the fabric.

[0020] Further, the establishment of the mesoscopic unit cell simulation model in step 4 specifically includes a mesoscopic unit cell simulation model containing fiber bundles, matrix, and interlayer.

[0021] Further, the damage quantities extracted in step 4 include the damage quantities in different directions of the fiber bundles, the damage quantity of the matrix, and the damage quantity of the interlayer.

[0022] The beneficial effects of the present invention are as follows:

[0023] 1. It can more accurately distinguish and simulate the real damage modes of fiber bundles and interlayers in composites. This new method takes into account the matrix damage and interface damage in the one-direction damage of the fiber bundle, as well as the interface damage and fiber damage in the two- and three-direction damages. In addition, it can more accurately analyze the interlayer damage of the fabric, distinguish matrix damage, fiber / matrix debonding damage, and fiber damage;

[0024] 2. It not only improves the understanding of the damage mechanism of composites, but also can provide more accurate data and predictions for material design and engineering applications; this is of great significance for improving the performance and reliability of composites, especially in the fields of aerospace, automotive industry, and high-performance engineering applications. In addition, this method may also open up new directions for future material research and development, promoting the progress and innovation of composite material technology;

[0025] 3. The present invention combines experimental and simulation methods to clarify the composition of the real damage mode in one direction within the fiber bundle in the simulation;

[0026] 4. The present invention combines experimental and simulation methods to clarify the composition of the real damage mode in two and three directions within the fiber bundle in the simulation;

[0027] 5. The present invention combines experimental and simulation methods to clarify the composition of the real damage mode in the fabric interlayer in the simulation;

[0028] 6. The simulation results obtained by the present invention are well verified with the damage modes of the macroscopic experiment;

[0029] 7. This method takes into account the fiber volume fraction within the fiber bundle and can accurately characterize the damage composition in each direction of the fiber bundle. Specific Embodiments

[0030] Specific Embodiment 1: The steps of a simulation method for composites based on acoustic emission described in this embodiment include:

[0031] Step 1: Conduct a tensile test to determine the characteristic parameters of acoustic emission signals corresponding to damage modes.

[0032] Step 2: Use acoustic emission technology to conduct a tensile test, perform cluster analysis on AE data to identify different damage modes in the tensile test, calculate the proportion of different damage modes based on the number of impacts of various damage modes, this proportion is the microscopic damage composition, and at the same time design tensile tests with different fiber volume fractions to obtain the relationship between the proportion of damage modes and fiber volume fractions.

[0033] Step 3: Design specific working condition experiments for the fabric based on AE technology, analyze the AE data through the clustering method, and calculate the distribution of each damage mode in the experimental results based on the number of impacts. The specific working conditions include tension, compression, and shear.

[0034] Step 4: Establish a mesoscopic unit cell simulation model of the fabric, apply boundary conditions according to specific working conditions for calculation, and extract the number of damages. The specific working conditions include tension, compression, and shear.

[0035] Step 5: Calculate the fiber bundle volume fraction of the fabric composite used in the experiment through metallographic inspection, and combine the relationship between the proportion of damage modes and fiber volume fractions obtained in Step 2 to determine the input of the damage proportion of fiber bundles and interlayer damages in subsequent simulations.

[0036] Step 6: According to the damage proportion, classify the complex damage modes obtained from the fabric specific working condition simulation into matrix damage, fiber / matrix debonding damage, and fiber damage. The specific working conditions include tension, compression, and shear.

[0037] Step 7: Compare with the experimental results to verify the simulation results.

[0038] Specific Embodiment 2: The tensile test described in Step 1 of the method for simulating composites based on acoustic emission in this embodiment includes a pure resin tensile test, a 45° unidirectional tape tensile test, an interlayer tensile test, and a 0° unidirectional tape tensile test.

[0039] Specific Embodiment 3: The damage modes described in Step 1 of the method for simulating composites based on acoustic emission in this embodiment include a matrix cracking damage mode, a fiber / matrix debonding damage mode, and a fiber fracture damage mode.

[0040] Specific Embodiment 4: Step 2 of the method for simulating composites based on acoustic emission in this embodiment specifically includes:

[0041] Step 201: Conduct a tensile experiment on the 0° unidirectional tape using acoustic emission technology. Perform cluster analysis on the AE data to identify different damage modes in the 0° unidirectional tape tensile experiment. Calculate the proportion of different damage modes based on the number of impacts of each damage mode. This proportion is the microscopic damage composition of the fiber bundle damage in one direction. At the same time, conduct tensile experiments on 0° unidirectional tapes with different volume fractions to obtain the relationship between the proportion of different damage modes and the fiber volume fraction.

[0042] Step 202: Conduct a tensile experiment on the 90° unidirectional tape using acoustic emission technology. Perform cluster analysis on the AE data to identify different damage modes in the 90° unidirectional tape tensile experiment. Calculate the proportion of different damage modes based on the number of impacts of each damage mode. This proportion is the microscopic damage composition of the fiber bundle damage in the second and third directions. At the same time, conduct tensile experiments on 90° unidirectional tapes with different volume fractions to obtain the relationship between the proportion of different damage modes and the fiber volume fraction.

[0043] Step 203: Conduct a tensile experiment on the fabric interlayer using acoustic emission technology. Perform cluster analysis on the AE data to identify different damage modes in the fabric interlayer tensile experiment. Calculate the proportion of different damage modes based on the number of impacts of each damage mode. This proportion is the microscopic damage composition of the fabric interlayer damage.

[0044] Specific Embodiment 5: In step 4 of the method for simulating a composite material based on acoustic emission described in this embodiment, establishing a mesoscopic unit cell simulation model specifically includes a mesoscopic unit cell simulation model containing fiber bundles, a matrix, and an interlayer.

[0045] Specific Embodiment 6: The damage quantities extracted in step 4 of the method for simulating a composite material based on acoustic emission described in this embodiment include the damage quantities in different directions of the fiber bundle, the damage quantity of the matrix, and the damage quantity of the interlayer.

[0046] Working Principle

[0047] The present invention proposes a simulation method based on acoustic emission that can distinguish the true damage modes of fiber bundles and interlayers.

[0048] First, identify the single damage modes of the composite material based on pure resin tensile, 45° unidirectional tape tensile, interlayer tensile, and 0° unidirectional tape tensile.

[0049] Conduct a tensile experiment on the 0° unidirectional tape using acoustic emission technology. Perform cluster analysis on the AE data to identify different damage modes in the 0° unidirectional tape tensile experiment. Calculate the proportion of different damage modes based on the number of impacts of each damage mode. This proportion is the microscopic damage composition of the fiber bundle damage in one direction.

[0050] The tensile experiment of 90° unidirectional tape is carried out by using acoustic emission technology. The AE data is subjected to cluster analysis to identify different damage modes in the tensile experiment of 90° unidirectional tape. Based on the impact numbers of each damage mode, the proportion of different damage modes is calculated, and this proportion is the microscopic damage composition of the damage in the second and third directions of the fiber bundle;

[0051] The interlaminar tensile experiment is carried out by using acoustic emission technology. The AE data is subjected to cluster analysis to identify different damage modes in the interlaminar tensile experiment. Based on the impact numbers of each damage mode, the proportion of different damage modes is calculated, and this proportion is the microscopic damage composition of the interlaminar damage;

[0052] According to the proportion of each damage mode, combined with the simulation results, the damage numbers in the first direction, second direction, and third direction of the fiber bundle, the matrix damage number, and the interlaminar damage number are extracted. All damage types can be classified into three types: matrix damage, fiber / matrix debonding damage, and fiber damage, and then verified by the results of the macroscopic test damage mode.

[0053] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments by using the above-disclosed technical content within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent replacement, and improvement made to the above embodiments within the spirit and principle of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A composite material simulation method based on acoustic emission, characterized in that: The steps of the composite material simulation method based on acoustic emission include: Step 1: Conduct a tensile test to determine the characteristic parameters of the acoustic emission signal corresponding to the damage mode; Step 2: Use acoustic emission technology to conduct tensile tests, and perform cluster analysis on AE data to identify different damage modes in the tensile test. Calculate the proportion of different damage modes based on the number of impacts of various damage modes. This proportion is the microscopic damage composition. At the same time, design tensile tests with different fiber volume fractions to obtain the relationship between the damage mode proportion and the fiber volume fraction. Step 201, using acoustic emission technology to perform a tensile test on a 0° unidirectional tape, performing cluster analysis on AE data to identify different damage modes in the 0° unidirectional tape tensile test, and calculating the proportion of different damage modes based on the number of impacts of each damage mode. This proportion is the microscopic damage composition of damage in one direction of the fiber bundle, and performing tensile tests on 0° unidirectional tapes with different volume fractions to obtain the relationship between the proportion of different damage modes and the fiber volume fraction; Step 202: Perform a tensile test on the 90° unidirectional tape using acoustic emission technology, perform cluster analysis on the AE data to identify different damage modes in the 90° unidirectional tape tensile test, calculate the proportion of different damage modes based on the number of impacts of each damage mode, and the proportion is the microscopic damage composition of the two- and three-directional damage of the fiber bundle. Perform tensile tests on 90° unidirectional tapes with different volume fractions at the same time to obtain the relationship between the proportion of different damage modes and the fiber volume fraction. Step 203: Perform a fabric interlayer stretching test using acoustic emission technology, perform cluster analysis on AE data to identify different damage modes in the fabric interlayer stretching test, and calculate the proportion of different damage modes based on the number of impacts of each damage mode. This proportion is the microscopic damage composition of the fabric interlayer damage. Step 3: designing a specific working condition experiment of the fabric based on AE technology, analyzing the AE data by a clustering method, and calculating the distribution of each damage mode in the experimental results based on the number of impacts, wherein the specific working conditions include tension, compression and shear; Step 4: Establish a fabric micro-unit cell simulation model, apply boundary conditions according to specific working conditions to perform calculations, and extract the amount of damage, wherein the specific working conditions include tension, compression, and shear; Step 5: Calculate the fiber bundle volume fraction of the fabric composite material used in the experiment through metallographic inspection, and determine the damage ratio input of the fiber bundle and interlayer damage in the subsequent simulation based on the relationship between the damage mode ratio and the fiber volume fraction obtained in step 2; Step 6: Classify the complex damage mode obtained by simulating the specific working condition of the fabric into matrix damage, fiber / matrix debonding damage and fiber damage according to the damage proportion, wherein the specific working condition includes tension, compression and shear; Step 7: Verify the simulation results by comparing them with the experimental results.

2. The composite material simulation method based on acoustic emission according to claim 1, characterized in that: The stretching test in step 1 includes a pure resin stretching test, a 45° unidirectional tape stretching test, an interlayer stretching test, and a 0° unidirectional tape stretching test.

3. The composite material simulation method based on acoustic emission according to claim 1, characterized in that: The damage modes described in step 1 include matrix cracking damage mode, fiber / matrix debonding damage mode and fiber breakage damage mode.

4. The composite material simulation method based on acoustic emission according to claim 1, characterized in that: The mesoscopic unit cell simulation model established in step 4 specifically includes a mesoscopic unit cell simulation model containing fiber bundles, matrix and interlayers.

5. The composite material simulation method based on acoustic emission according to claim 1, characterized in that: The number of damages extracted in step 4 includes the number of damages in different directions of the fiber bundle, the number of damages in the matrix, and the number of damages between layers.