CN-115659712-B - Method for simulating wave absorbing performance of carbon nanotube-covered fabric composite material

Abstract

The invention discloses a carbon nanotube covered fabric composite material wave absorbing performance simulation method, which comprises carbon nanotube microstructure homogenization analysis, carbon nanotube-glass fiber mesostructure homogenization analysis and carbon nanotube covered fabric composite material macrostructure homogenization analysis, wherein the carbon nanotube microstructure homogenization analysis comprises the steps of establishing a carbon nanotube composite material microstructure model by using a Monte-Carlo method, dividing the carbon nanotube composite material microstructure model into tetrahedral grids, calculating the conductivity of the carbon nanotube composite material under different filling densities by using an independently written finite element program, calculating the electromagnetic shielding performance of the carbon nanotube covered fabric composite material under different carbon nanotube lengths, densities and weaving modes by using a numerical simulation method, and deeply understanding the physical mechanism behind the wave absorbing performance by using the numerical simulation result, so that the structural design of the structural wave absorbing composite material can be better guided, and the design scheme is effectively guided.

Inventors

• LU XIAOXIN
• Qu Hengtong

Assignees

• 安徽铸脊新材料科技有限公司

Dates

Publication Date

20260512

Application Date

20220616

Claims (3)

1. 1. The method for simulating the wave absorbing performance of the fabric composite material covered with the carbon nano tube is characterized by comprising the following steps of: S1, homogenizing analysis of microstructure of carbon nano tube 1) Establishing a microstructure model of the carbon nano tube composite material by using a Monte-Carlo method, wherein the carbon nano tubes are parallel to each other and are not crossed and contacted with each other, and the structure meets periodic boundary conditions; 2) Dividing a microstructure model of the carbon nanotube composite material into tetrahedral grids, calculating the shortest distance between each end point of the finite element grid and all carbon nanotube segments in the system, and calculating the conductivity of the carbon nanotube composite material under different filling densities by utilizing a finite element program; the weak form derivation process of the finite element procedure in step S1 is as follows: Sum of potential energy density in matrix resin and potential energy density in carbon nanotubes ; Wherein the potential energy density of the matrix Potential energy density of CNT ; Minimizing the total energy of the system along the electric field direction, and obtaining a finite element weak form as follows: ; Potential energy inside the matrix ; If the distance function of a point in the system is larger than the cutoff distance of the tunneling current The resin is a common resin part, has no tunneling current, and is smaller than The presence of tunneling current needs to be considered at this point; respectively applying potential differences in the main directions of the representative volume units, and calculating average current and average electric field intensity in the system by the finite element method, wherein the ratio of the average current to the average electric field intensity is the effective conductivity of the system; s2, homogenizing analysis of mesostructure of carbon nano tube-glass fiber 1) Establishing a carbon nano tube composite material-glass fiber mesoscopic structure model which is a glass fiber structure uniformly coated by carbon nano tubes; 2) Calculating the conductivity and the dielectric coefficient of the mesoscopic structure model of the carbon nano tube composite material by using a finite element method; S3, homogenizing analysis of macrostructure of fabric composite material covered with carbon nano tube 1) Establishing a representative volume unit of a glass fiber woven structure model by utilizing COMSOL, wherein the representative volume unit is a double-layer cylinder, the inner layer is glass fiber, the thickness of the outer layer is consistent with the length of a grown carbon nano tube, and the dielectric property and the conductivity of the outer layer are the values obtained in S1; 2) And (3) carrying the conductivity and the dielectric coefficient of the glass fiber structure coated with the carbon nano tubes calculated in the S2 in the AC/DC module, and calculating the wave absorbing performance of the glass fiber braiding system with the carbon nano tubes grown, wherein the distance and the arrangement mode between the glass fibers are adjustable.
2. 2. The method for simulating the wave absorbing performance of a carbon nanotube-covered fabric composite according to claim 1, wherein in the step S1, a distance function of endpoints of a finite element mesh in a system is: , Wherein, the For the van der waals distance, For the sum of the values of the shortest distance of the smallest two endpoints and all CNT segments, Is the diameter of the carbon nanotube.
3. 3. The method for simulating the wave absorbing performance of a carbon nanotube-covered fabric composite according to claim 1, wherein the finite element program in step S1 is written by MATLAB.

Description

Method for simulating wave absorbing performance of carbon nanotube-covered fabric composite material Technical Field The invention relates to the technical field of composite materials, in particular to a method for simulating wave absorbing performance of a fabric composite material covered with carbon nanotubes. Background Due to the rapid development of electronic devices, electromagnetic absorbers have attracted extensive research attention to reduce interference with other devices and to protect human health from potential electromagnetic radiation. Electromagnetic wave absorbing materials are mainly divided into two main types, namely surface coating materials and structural electromagnetic wave absorbing materials, wherein the latter are very attractive for fields requiring light weight and strength, such as aerospace and the like. Glass fiber is a widely used structural material, and researchers grow carbon nanotubes on the surface of the glass fiber through chemical vapor deposition recently to develop a high-performance structural wave-absorbing composite material. However, there is no progress in intensive research on the effect of the length, density of the grown carbon nanotubes and the weaving scheme of the glass fiber fabric on the electromagnetic shielding performance thereof. In order to better guide the structural design of the wave-absorbing composite material with the structure, a high-efficiency accurate numerical model is required to be provided for simulating the wave-absorbing performance of the material, and the physical mechanism behind the wave-absorbing performance is deeply understood through the result of numerical simulation. Disclosure of Invention This section is intended to outline some aspects of embodiments of the application and to briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section as well as in the description of the application and in the title of the application, which may not be used to limit the scope of the application. The present invention has been made in view of the above-mentioned and/or existing problems in the development of high performance structural wave-absorbing composites. Therefore, the invention aims to provide a method for simulating the wave absorbing performance of a fabric composite material covered with carbon nanotubes, which calculates the electromagnetic shielding performance of the fabric composite material covered with carbon nanotubes under different lengths, densities and weaving modes by using a numerical simulation method, thereby playing a high-efficiency guiding role on the design scheme of the product. In order to solve the technical problems, according to one aspect of the present invention, the following technical solutions are provided: the method for simulating the wave absorbing performance of the fabric composite material covered with the carbon nano tube is characterized by comprising the following steps of: S1, homogenizing analysis of microstructure of carbon nano tube 1) Establishing a microstructure model of the carbon nano tube composite material by using a Monte-Carlo method, wherein the carbon nano tubes are parallel to each other and are not crossed and contacted with each other, and the structure meets periodic boundary conditions; 2) Dividing a microstructure model of the carbon nanotube composite material into tetrahedral grids, calculating the shortest distance between each end point of the finite element grid and all carbon nanotube segments in the system, and calculating the conductivity of the carbon nanotube composite material under different filling densities by utilizing a finite element program; s2, homogenizing analysis of mesostructure of carbon nano tube-glass fiber 1) Establishing a mesoscopic structure model of the carbon nano tube-glass fiber composite material; 2) Calculating the conductivity and the dielectric coefficient of a glass fiber structure coated with carbon fibers in a mesoscopic structure model of the carbon nanotube composite material by using a finite element method; S3, homogenizing analysis of macrostructure of fabric composite material covered with carbon nano tube 1) Establishing a glass fiber woven structure model by utilizing COMSOL; 2) The conductivity and the dielectric coefficient of the glass fiber and the carbon nano tube calculated in the S2 are brought into an AC/DC module, so that the wave absorbing performance of the glass fiber system with the carbon nano tube is obtained; 3) A representative volume element of the glass fiber weave structural model is calculated, wherein the distance and arrangement between the glass fibers are adjustable. As a preferred scheme of the method for simulating the wave absorbing performance of the carbon nanotube-covered fabric composite material, in the step S2, a distance function of endpoints of the finite element mesh in the system is as follows: , Wherein, the For the van der waa