A method for testing and inverse calculation of intrinsic electromagnetic parameters of each component of an absorbing honeycomb

Abstract

A method for testing and inversely calculating the intrinsic electromagnetic parameters of each component of an absorbing honeycomb is disclosed. This method addresses the problem of being unable to accurately measure the intrinsic electromagnetic parameters of these components when only a finished absorbing honeycomb sandwich structure is available but the raw materials are unavailable. The method first sequentially measures the cross-sectional geometric dimensions of a honeycomb core structure without and with an absorbing coating, as well as the equivalent relative complex electromagnetic parameters of the overall structure. The method then inversely calculates the intrinsic electromagnetic parameters of the honeycomb core material and the absorbing coating. This method belongs to the technical field of material electromagnetic property testing.

Description

Technical Field

[0001] The invention relates to a testing and inversion calculation method, and belongs to the technical field of material electromagnetic performance testing. Background Art

[0002] The absorbing honeycomb sandwich structure has the ability to absorb electromagnetic waves, and therefore has important applications in structural stealth design and other aspects. The absorbing honeycomb core structure is made by impregnating the surface of the honeycomb core material with an absorbing coating, and contains three different components: air, honeycomb core material, and absorbing coating. Clarifying the electromagnetic parameters of these different components is crucial for guiding the optimal design of the absorbing honeycomb core structure and its repair design after damage. Traditional methods usually rely on the raw materials of the honeycomb core material and the absorbing coating to prepare test samples of specific sizes, and use testing methods such as the transmission line method to determine the intrinsic electromagnetic parameters of each component. However, in actual applications, when only the finished product of the absorbing honeycomb sandwich structure is available but the raw materials cannot be obtained, how to accurately measure the intrinsic electromagnetic parameters of these components has become a technical problem that needs to be solved urgently. Summary of the Invention

[0003] The present invention aims to solve the problem of being unable to accurately measure the intrinsic electromagnetic parameters of components when only a finished product of an absorbing honeycomb sandwich structure is available but its raw materials cannot be obtained, and further proposes a method for testing and inversely calculating the intrinsic electromagnetic parameters of each component of the absorbing honeycomb.

[0004] The technical solution adopted by the present invention to solve the above problems is: the steps of the present invention include:

[0005] Step 1: Measure the geometric parameters of the interfaces of the components of the honeycomb core structure without the absorbing coating, and calculate the volume ratio of the honeycomb core material to the honeycomb core structure.

[0006] Step 2: Measure and obtain the equivalent electromagnetic parameters of the honeycomb core structure;

[0007] Step 3: Based on the relative electromagnetic parameter ε of air 11 =1 and μ 11 =1, inverse calculation of the relative complex dielectric constant ε of the honeycomb core material 12 =ε1′2–jε1″2 and relative complex permeability μ 12 =μ1′2-jμ1″2;

[0008] Step 4: Measure the cross-sectional geometric parameters of each component of the absorbing honeycomb core structure containing the absorbing coating, and calculate the volume ratio of the honeycomb core material and the absorbing coating to the absorbing honeycomb core structure. and

[0009] Step 5: Measure and obtain the equivalent electromagnetic parameters of the wave-absorbing honeycomb core structure;

[0010] Step 6: Consider the air and absorbing coating of the absorbing honeycomb core structure as equivalent structures, and calculate the relative electromagnetic parameters ε of the honeycomb core material. 22 =ε 12 =ε2′2-jε2″2=ε1′2-jε1″2, μ 22 =μ 12 =μ2′2-jμ2″2=μ1′2-jμ1″2, inverse calculation of the relative complex dielectric constant ε of the equivalent structure 24 =ε2′4-jε2″4 and relative complex permeability μ 24 =μ2′4-jμ2″4;

[0011] Step 7: Calculate the volume ratio of the absorbing coating in the absorbing honeycomb core structure to the equivalent structure Then the relative complex dielectric constant ε of the absorbing coating is calculated by inversion 23 =ε2′3-jε2″3 and relative complex permeability μ 23 =μ2′3-μ2″3.

[0012] Furthermore, in step 2, the equivalent electromagnetic parameters of the honeycomb core structure are measured using a transmission line method or a free space method.

[0013] Furthermore, the equivalent electromagnetic parameters in step 2 include relative complex permittivity ε1=ε1′-jε1″ and relative complex permeability μ1=μ1′-jμ1″.

[0014] Furthermore, the calculation formula in step 3 is as follows:

[0015]

[0016] Furthermore, in step 5, the equivalent electromagnetic parameters of the absorbing honeycomb core structure are measured using the transmission line method or the free space method, and the equivalent electromagnetic parameters include the relative dielectric constant ε2=ε2′-jε2″ and the relative magnetic permeability μ2=μ2′-jμ2″.

[0017] Furthermore, the calculation formula in step 6 is:

[0018]

[0019] Furthermore, the calculation formula in step 7 is:

[0020]

[0021] The beneficial effects of the present invention are as follows: the present invention provides a method for inverting and calculating the intrinsic electromagnetic parameters of each component in the wave-absorbing honeycomb core structure by testing the equivalent electromagnetic parameters of the entire wave-absorbing honeycomb core structure; the present invention only needs to test the already prepared honeycomb core structure and the wave-absorbing honeycomb core structure, and there is no need to additionally prepare single material samples of the raw materials of each component, which not only removes the restrictions on the acquisition of component raw materials, but also significantly reduces the cost and complexity of testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the honeycomb core structure;

[0023] Figure 2 It is a schematic diagram of the structure of the wave-absorbing honeycomb core;

[0024] Figure 3 It is a schematic diagram of the equivalent structure of the wave-absorbing honeycomb core structure;

[0025] Figure 4 Schematic diagram of the real part ε1′, ε2′ and the imaginary part ε1″, ε2″ of the equivalent dielectric constant of the honeycomb core structure and the wave-absorbing honeycomb core structure;

[0026] Figure 5 It is a schematic diagram of the inverse calculation of the real part ε1′2, ε2′3 and the imaginary part ε1″2, ε2″3 of the relative complex dielectric constant of the honeycomb core material and the absorbing coating;

[0027] Figures 1 to 3 In the figure, 1-honeycomb core structure, 11-air, 12-honeycomb core material, 2-wave-absorbing honeycomb core structure, 21-air, 22-honeycomb core material, 23-wave-absorbing coating, and 24-equivalent structure. DETAILED DESCRIPTION

[0028] Specific implementation method 1: Figures 1 to 3 As shown, a method for testing and inversely calculating the intrinsic electromagnetic parameters of each component of a wave-absorbing honeycomb is used to measure the interface geometric parameters of each component of a honeycomb core structure 1 without a wave-absorbing coating, and to calculate the volume ratio of the honeycomb core material 12 to the honeycomb core structure 1.

[0029] Step 2: Using a transmission line method or a free space method to measure and obtain equivalent electromagnetic parameters of the honeycomb core structure 1, the equivalent electromagnetic parameters including relative complex permittivity ε1=ε1′-jε1″ and relative complex permeability μ1=μ1′-jμ1″;

[0030] Step 3: Based on the relative electromagnetic parameter ε of the air 11 11 =1 and μ 11 =1, inverse calculation of the relative complex dielectric constant ε of the honeycomb core material 12 =ε1′2–jε1″2 and relative complex permeability μ 12=μ1′2-jμ1″2; the calculation formula is as follows:

[0031]

[0032] Step 4: Measure the cross-sectional geometric parameters of each component of the absorbing honeycomb core structure 2 containing the absorbing coating, and calculate the volume ratio of the honeycomb core material 22 and the absorbing coating 23 to the absorbing honeycomb core structure 2. and

[0033] Step 5: Use the transmission line method or the free space method to measure and obtain the equivalent electromagnetic parameters of the absorbing honeycomb core structure 2, wherein the equivalent electromagnetic parameters include the relative dielectric constant ε2=ε2′-jε2″ and the relative magnetic permeability μ2=μ2′-jμ2″;

[0034] Step 6: The air 21 and the absorbing coating 23 of the absorbing honeycomb core structure 2 are regarded as equivalent structures 24, and the relative electromagnetic parameters ε of the honeycomb core material are calculated. 22 =ε 12 =ε2′2-jε2″2=ε1′2-jε1″2, μ 22 =μ 12 =μ2′2-jμ2″2=μ1′2-jμ1″2, inverse calculation of the relative complex dielectric constant ε of the equivalent structure 24 24 =ε2′4-jε2″4 and relative complex permeability μ 24 =μ2′4-jμ2″4; the calculation formula is:

[0035]

[0036] Step 7: Calculate the volume ratio of the absorbing coating 23 in the absorbing honeycomb core structure 2 to the equivalent structure 24 Then the relative complex dielectric constant ε of the absorbing coating 23 is inversely calculated 23 =ε2′3-jε2″3 and relative complex permeability μ 23 =μ2′3-μ2″3; the calculation formula is:

[0037]

[0038] Example

[0039] Taking a honeycomb core structure made of Nomex core material and an absorbing honeycomb core structure impregnated with an absorbing coating as examples, the testing and calculation process of the intrinsic electromagnetic parameters of each component is described in detail. Since each component of this absorbing honeycomb core is non-magnetic (relative permeability is 1), only the intrinsic relative complex permittivity of each component is inverted and calculated.

[0040] Measure the cross-sectional geometric parameters of the honeycomb core structure 1 composed of Nomex core material, and calculate the volume ratio of the honeycomb core material 12 to the honeycomb core structure 1 The real part ε1′ and imaginary part ε1″ of the equivalent dielectric constant of the honeycomb core structure 1 are measured as follows: Figure 4 Based on the calculation process of step 3, the real part ε1′2 and imaginary part ε1″2 of the relative complex dielectric constant of the honeycomb core material are inversely calculated as follows: Figure 5 shown.

[0041] Measure the cross-sectional geometric parameters of each component of the wave-absorbing honeycomb core structure 2, and calculate the volume ratio of the honeycomb core material 22 and the wave-absorbing coating 23 to the wave-absorbing honeycomb core structure 2. and The real part ε2′ and imaginary part ε2″ of the equivalent dielectric constant of the absorbing honeycomb core structure 2 are measured as follows: Figure 4 Based on the calculation process of steps 5 and 6, the real part ε2′3 and the imaginary part ε2″3 of the relative complex dielectric constant of the absorbing coating are inversely calculated as follows: Figure 5 shown.

[0042] In the present invention, the honeycomb core material of the honeycomb structure without coating and the honeycomb core material of the wave-absorbing honeycomb structure with wave-absorbing coating are made of the same material.

[0043] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the present profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical content disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement of the above embodiments made according to the technical essence of the present invention, within the spirit and principles of the present invention, without departing from the content of the technical solution of the present invention, shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for testing and inversely calculating the intrinsic electromagnetic parameters of each component of an absorbing honeycomb, characterized in that: The specific steps include: Step 1: Measure the cross-sectional geometric parameters of each component of the honeycomb core structure (1) without the absorbing coating, and calculate the volume ratio of the honeycomb core material (12) to the honeycomb core structure (1). ; Step 2: measuring and obtaining equivalent electromagnetic parameters of the honeycomb core structure (1); Step 3: Based on the relative electromagnetic parameters of air (11) and , inverse calculation of the relative complex dielectric constant of the honeycomb core material and relative complex permeability ; Step 4: Measure the cross-sectional geometric parameters of each component of the absorbing honeycomb core structure (2) containing the absorbing coating, and calculate the volume ratio of the honeycomb core material (22) and the absorbing coating (23) to the absorbing honeycomb core structure (2). and ; Step 5, measuring and obtaining the equivalent electromagnetic parameters of the wave-absorbing honeycomb core structure (2); Step 6: Consider the air (21) and the absorbing coating (23) of the absorbing honeycomb core structure (2) as an equivalent structure (24), and calculate the relative electromagnetic parameters of the honeycomb core material. , , inverse calculation of the relative complex permittivity of the equivalent structure (24) and relative complex permeability ; Step 7: Calculate the volume ratio of the absorbing coating (23) in the absorbing honeycomb core structure (2) to the equivalent structure (24). φ 234 = φ 23 / (1– φ 22 ), and then inversely calculate the relative complex dielectric constant of the absorbing coating (23) and relative complex permeability .

2. The method for testing and inversely calculating the intrinsic electromagnetic parameters of each component of an absorbing honeycomb according to claim 1, characterized in that: In step 2, the equivalent electromagnetic parameters of the honeycomb core structure (1) are measured using a transmission line method or a free space method.

3. The method for testing and inversely calculating the intrinsic electromagnetic parameters of each component of an absorbing honeycomb according to claim 1, characterized in that: The equivalent electromagnetic parameters described in step 2 include the relative complex permittivity and relative complex permeability .

4. The method for testing and inversely calculating the intrinsic electromagnetic parameters of each component of an absorbing honeycomb according to claim 3, characterized in that: The calculation formula in step 3 is as follows: 。 5. The method for testing and inversely calculating the intrinsic electromagnetic parameters of each component of an absorbing honeycomb according to claim 1, characterized in that: In step 5, the equivalent electromagnetic parameters of the absorbing honeycomb core structure (2) are measured using the transmission line method or the free space method. The equivalent electromagnetic parameters include the relative dielectric constant and relative magnetic permeability .

6. The method for testing and inversely calculating the intrinsic electromagnetic parameters of each component of an absorbing honeycomb according to claim 5, characterized in that: The calculation formula in step 6 is: 。 7. The method for testing and inversely calculating the intrinsic electromagnetic parameters of each component of a microwave-absorbing honeycomb according to claim 1, characterized in that: The calculation formula in step 7 is: 。

Images