A chiral origami honeycomb optimization design method

Abstract

The application belongs to the field of honeycomb design, and relates to a chiral origami honeycomb optimization design method, which comprises the following steps: step one, determining design parameters of the chiral origami honeycomb and a value range of the design parameters; step two, selecting model calculation samples in the value range of the design parameters of the chiral origami honeycomb; step three, establishing an electromagnetic calculation model of the chiral origami honeycomb in electromagnetic analysis software, calculating the model calculation samples, and obtaining corresponding total effective anti-reflection bandwidth EAB; step four, establishing a characteristic calculation model of the chiral origami honeycomb in finite element analysis software, calculating the model calculation samples, and obtaining corresponding equivalent stiffness E and equivalent density Density; step five, establishing an EAB-E-Density approximate calculation model of the chiral origami honeycomb; and step six, taking the maximum total effective anti-reflection bandwidth EAB as a target, performing optimization in the value range of the design parameters of the chiral origami honeycomb under the constraints of the equivalent stiffness E and the equivalent density Density, and obtaining optimized design parameters.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of honeycomb design, and particularly relates to a chiral origami honeycomb optimization design method. BACKGROUND

[0002] Honeycomb structures have good bearing capacity and anti-reflection performance, and are widely used in aircraft structures such as fuselage panels and partitions.

[0003] In honeycomb structures, regular hexagonal honeycombs are usually used. The regular hexagonal honeycomb has poor rigidity and poor anti-reflection bandwidth adjustability, and has been difficult to meet the current requirements of aircraft structure design for multi-band coverage, efficient bearing and lightweight.

[0004] Chiral origami has good axial and torsional coupling and has a multi-stable state. By embedding chiral origami into a honeycomb to form a boundary constraint and replacing a hexagonal honeycomb, a chiral origami honeycomb is obtained, as shown in Figure 1 , which is arranged in a periodic array to construct a chiral origami honeycomb structure, as shown in Figure 2 .

[0005] The chiral origami honeycomb can produce an electric field aggregation effect, and an induced current is formed between the gaps crossed by electromagnetic waves, which can effectively improve the poor side anti-reflection performance of the regular hexagonal honeycomb. When subjected to pressure, the chiral origami honeycomb can rotate and fold while producing wrinkle buckling, and preferentially deforms and absorbs energy before being damaged. Therefore, the chiral origami honeycomb has better bearing capacity than the regular hexagonal honeycomb and can be better applied in aircraft structures.

[0006] The chiral origami honeycomb has more design parameters than the regular hexagonal honeycomb. When the height h is constant, the typical design parameters include the large regular hexagonal edge length R1 at both ends, the small regular hexagonal edge length R2 in the middle, the torsion angle φ between the large regular hexagonal edge at both ends and the small regular hexagonal edge in the middle, and the wall thickness t. The chiral origami honeycomb has good adjustability in terms of structural rigidity and anti-reflection bandwidth.

[0007] However, when designing the chiral origami honeycomb, only the design of structural rigidity or anti-reflection bandwidth is often considered, and the current requirements of aircraft structure design for multi-band coverage, efficient bearing and lightweight cannot be well met.

[0008] The present application is proposed in view of the above technical defects. SUMMARY

[0009] The purpose of the present application is to provide a chiral origami honeycomb optimization design method to overcome or alleviate at least one aspect of the known technical defects.

[0010] The technical solution of the present application is:

[0011] A chiral origami honeycomb optimization design method comprises:

[0012] Step one, determine the design parameters of chiral origami honeycomb and its value range;

[0013] Step two, select model calculation samples in the value range of chiral origami honeycomb design parameters;

[0014] Step three, in the electromagnetic analysis software, establish the electromagnetic calculation model of chiral origami honeycomb, calculate the model calculation samples to obtain the corresponding total effective anti-reflection bandwidth EAB;

[0015] Step four, in the finite element analysis software, establish the characteristic calculation model of chiral origami honeycomb, calculate the model calculation samples to obtain the corresponding equivalent stiffness E and equivalent density Density;

[0016] Step five, establish the EAB-E-Density approximate calculation model of chiral origami honeycomb with the model calculation samples and their corresponding total effective anti-reflection bandwidth EAB, equivalent stiffness E and equivalent density Density;

[0017] Step six, take the maximum total effective anti-reflection bandwidth EAB as the target, constrain the equivalent stiffness E and equivalent density Density, calculate the total effective anti-reflection bandwidth EAB, equivalent stiffness E and equivalent density Density of chiral origami honeycomb by using the EAB-E-Density approximate calculation model, optimize in the value range of design parameters to obtain the optimized design parameters.

[0018] Optionally, in the chiral origami honeycomb optimization design method, in step one, the design parameters of chiral origami honeycomb include the length R1 of the large regular hexagon at both ends, the length R2 of the small regular hexagon in the middle, the twist angle φ between the large regular hexagon at both ends and the small regular hexagon in the middle, and the wall thickness t.

[0019] Optionally, in the chiral origami honeycomb optimization design method, in step one, the length R1 of the large regular hexagon at both ends is in the range of 3mm-6mm, the length R2 of the small regular hexagon in the middle is in the range of 2mm-6mm, the twist angle φ between the large regular hexagon at both ends and the small regular hexagon in the middle is in the range of -60°-60°, the wall thickness t is in the range of 0.4mm-1mm, and R2≤R1.

[0020] Optionally, in the chiral origami honeycomb optimization design method, in step two, optimal Latin hypercube sampling is performed in the value range of chiral origami honeycomb design parameters to select model calculation samples.

[0021] Optionally, in the chiral origami honeycomb optimization design method, in step five, the equivalent stiffness E and equivalent density Density are constrained, specifically:

[0022] E_0;

[0023] Density≤Density _0;

[0024] Wherein,

[0025] E_0 is the constraint value of equivalent stiffness, taking 1200MPa;

[0026] Density _0 is the constraint value of equivalent density, taking 500 kg / m³.

[0027] Optionally, in the chiral origami honeycomb optimization design method, in step five, the multi-island genetic algorithm is used to optimize in the value range of the chiral origami honeycomb design parameters to obtain the optimized design parameters.

[0028] The present application has at least the following beneficial technical effects:

[0029] The present application provides a chiral origami honeycomb optimization design method, which takes the maximum total effective anti-reflection bandwidth EAB as the target, and constrains the equivalent stiffness E and the equivalent density Density. The EAB-E-Density approximate calculation model is used to calculate the total effective anti-reflection bandwidth EAB, the equivalent stiffness E and the equivalent density Density of the chiral origami honeycomb, and the optimization is performed in the value range of the design parameters to obtain the optimized design parameters, so that the chiral origami honeycomb optimization design is realized. The process is simple and efficient, and is applied to the aircraft structure design, which can well adapt to the current requirements of multi-frequency coverage, efficient bearing and light weight for aircraft structure design. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a configuration diagram of the existing chiral origami honeycomb;

[0031] Figure 2 is a perspective view of the existing chiral origami honeycomb structure;

[0032] Figure 3 is a flowchart of the chiral origami honeycomb optimization design method provided by the present application;

[0033] Figure 4 is a comparison diagram of the electromagnetic wave reflection loss of the chiral origami honeycomb before and after the optimization design in the frequency range of 1-18GHz.

[0034] In order to better illustrate the present application, some contents in the drawings may be omitted, enlarged or reduced, which are only used for exemplary description and cannot be understood as a limitation of the present application. DETAILED DESCRIPTION

[0035] In order to make the technical solutions of the present application and its advantages clearer, the technical solutions of the present application will be further clearly and completely described below in combination with the drawings. It should be understood that the specific embodiments described herein are only part of the embodiments of the present application, which are only used to explain the present application, but not to limit the present application. It should be noted that, for the purpose of description, only parts related to the present application are shown in the drawings, and other related parts can be referred to the general design.

[0036] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of the present application should be the general meanings understood by the general skilled person in the field to which the present application belongs. In the description of the present application, "including" indicates that the concept appearing before the word covers the concepts listed after the word and its equivalents, without excluding other related concepts.

[0037] A chiral origami honeycomb optimization design method, as shown in Figure 3 .

[0038] Step one, determine the design parameters of the chiral origami honeycomb and its value range.

[0039] In the case of fixing the height h of the chiral origami honeycomb to 30mm, the design parameters of the chiral origami honeycomb can be determined, including the edge length R1 of the large regular hexagon at both ends, the edge length R2 of the small regular hexagon in the middle, the twist angle φ between the large regular hexagon at both ends and the small regular hexagon in the middle, and the wall thickness t, wherein the value range of the edge length R1 of the large regular hexagon at both ends can be determined as 3mm ~ 6mm, the value range of the edge length R2 of the small regular hexagon in the middle can be determined as 2mm ~ 6mm, the value range of the twist angle φ between the large regular hexagon at both ends and the small regular hexagon in the middle can be determined as -60° ~ 60°, the value range of the wall thickness t can be determined as 0.4mm ~ 1mm, and R2≤R1.

[0040] For the chiral origami honeycomb, a composite wire material can be prepared by carbon nanotube and polyether ether ketone melt blending, and integrated molding by melt deposition 3D printing, wherein the weight percentage of carbon nanotube is 5% ~ 10%.

[0041] Step two, select model calculation samples within the value range of the design parameters of the chiral origami honeycomb.

[0042] Within the value range of the design parameters of the chiral origami honeycomb, optimal Latin hypercube sampling is performed to select model calculation samples, and specifically 107 model calculation samples uniformly distributed in the design space can be obtained.

[0043] Step three, in the electromagnetic analysis software, an electromagnetic calculation model of the chiral origami honeycomb is established, the model calculation samples are calculated, and the corresponding total effective anti-reflection bandwidth EAB is obtained.

[0044] In electromagnetic analysis software CST, the electromagnetic calculation model of chiral origami honeycomb is established, the electromagnetic parameters of chiral origami honeycomb material are input, the X-axis and Y-axis directions are defined as the unit period boundary, the Z-axis positive direction is defined as the electromagnetic wave incidence direction, the frequency range of electromagnetic wave is set to 1-18GHz, and the electromagnetic wave bandwidth with a reflection loss less than-4dB in the 1-2GHz frequency band is set as the effective anti-reflection bandwidth, the electromagnetic wave bandwidth with a reflection loss less than-6dB in the 2-4GHz frequency band is set as the effective anti-reflection bandwidth, the electromagnetic wave bandwidth with a reflection loss less than-10dB in the 4-8GHz frequency band is set as the effective anti-reflection bandwidth, the electromagnetic wave bandwidth with a reflection loss less than-13dB in the 8-12GHz frequency band is set as the effective anti-reflection bandwidth, and the electromagnetic wave bandwidth with a reflection loss less than-11dB in the 12-18GHz frequency band is set as the effective anti-reflection bandwidth, and then the model calculation sample is calculated to obtain the total effective anti-reflection bandwidth EAB corresponding to each frequency band.

[0045] Step four, in the finite element analysis software, the characteristic calculation model of chiral origami honeycomb is established, the model calculation sample is calculated, and the corresponding equivalent stiffness E and equivalent density Density are obtained.

[0046] In the finite element analysis software, the characteristic calculation model of chiral origami honeycomb is established, the characteristic parameters of chiral origami honeycomb material are input, and the periodic boundary condition is applied, and then the model calculation sample is calculated to obtain the corresponding equivalent stiffness E and equivalent density Density.

[0047] The electromagnetic calculation model and the characteristic calculation model of chiral origami honeycomb are used to calculate the model calculation sample to obtain the corresponding total effective anti-reflection bandwidth EAB, equivalent stiffness E and equivalent density Density, which mostly meet the requirements of chiral origami honeycomb response, and tend to a straight line without large-scale fluctuation, indicating that the model calculation sample selected by optimal Latin hypercube sampling is reasonable and effective.

[0048] Step five, the EAB-E-Density approximate calculation model of chiral origami honeycomb is established based on the model calculation sample and the corresponding total effective anti-reflection bandwidth EAB, equivalent stiffness E and equivalent density Density.

[0049] The design parameters in the model calculation sample have different unit dimensions, which will affect the results of data analysis. In order to eliminate the influence of dimension, Min-Max standardization processing method can be used to linearly transform the value of design parameters and map them to [0, 1].

[0050] Based on RBF radial basis function, the EAB-E-Density approximate calculation model of chiral origami honeycomb is established.

[0051] To ensure the accuracy of the EAB-E-Density approximate calculation model of chiral origami honeycomb, a fitting evaluation coefficient is introduced The EAB-E-Density approximate calculation model is evaluated, The closer to 1 indicates that the EAB-E-Density approximate calculation model is more reliable, and the specific design The EAB-E-Density approximate calculation model is considered reliable, otherwise, the EAB-E-Density approximate calculation model calculation is modified.

[0052] The final calculation of the total effective anti-reflection bandwidth EAB is 0.971, the equivalent stiffness E is 0.993, and the equivalent density Density is 0.997, all greater than 0.95 and very close to 1, indicating that the fitting effect of the EAB-E-Density approximate calculation model of chiral origami honeycomb is good, the reliability is high, and the calculation of the total effective anti-reflection bandwidth EAB, equivalent stiffness E, and equivalent density Density of chiral origami honeycomb is more accurate.

[0053] Step six, taking the maximum total effective anti-reflection bandwidth EAB as the target, constraining the equivalent stiffness E and the equivalent density Density, using the EAB-E-Density approximate calculation model, calculating the total effective anti-reflection bandwidth EAB, equivalent stiffness E, and equivalent density Density of chiral origami honeycomb, and optimizing in the value range of the design parameters to obtain the optimized design parameters and realize the optimization design of chiral origami honeycomb.

[0054] The expression for optimizing in the value range of the design parameters of chiral origami honeycomb is:

[0055] Find {R1, R2, φ, t};

[0056] Max EAB;

[0057] s.t. E> E_0;

[0058] Density≤Density _0;

[0059] Wherein,

[0060] E_0 is the constraint value of equivalent stiffness, which can be specifically taken as 1200MPa;

[0061] Density _0 is the constraint value of equivalent density, which can be specifically taken as 500 kg / m³.

[0062] The multi-island genetic algorithm can be used, the sub-population is set to 40, the island number is 20, the genetic evolution generation is 30 generations, the total generation number is 24000 times, the optimization is carried out in the value range of the design parameters of the chiral origami honeycomb, and the optimized design parameters are obtained.

[0063] After iterative calculation, the optimized design parameters of the chiral origami honeycomb are R1=5.4mm, R2=4.4mm, φ=-6° and t=1mm.

[0064] The comparison of electromagnetic wave reflection loss of the chiral origami honeycomb before and after optimization design in the frequency range of 1-18GHz is shown in the figure Figure 4 It can be seen from the figure that the optimized chiral origami honeycomb has greater improvement in electromagnetic wave reflection loss and electromagnetic wave absorption degree, the total effective anti-reflection bandwidth EAB is larger, and has better anti-reflection bandwidth. The optimization design is made under the constraint of equivalent stiffness E and equivalent density Density, and can well balance the bearing and lightweight, and is applied to the aircraft structure design, and can well adapt to the current requirements of multi-frequency coverage, efficient bearing and lightweight for aircraft structure design.

[0065] The technical scheme of the application has been described in combination with the preferred embodiments shown in the drawings, and those skilled in the art should understand that the protection scope of the application is obviously not limited to these specific embodiments, and those skilled in the art can make equivalent changes or replacements to the related technical features without departing from the principles of the application, and the technical scheme after the changes or replacements will fall within the protection scope of the application.

Claims

1. A method for optimizing the design of chiral origami honeycomb, characterized in that, include: Step 1: Determine the design parameters and value range of the chiral origami honeycomb; Step 2: Within the range of values ​​for the chiral origami honeycomb design parameters, select a model calculation sample; Step 3: In the electromagnetic analysis software, establish the electromagnetic calculation model of the chiral origami honeycomb, calculate the model calculation sample, and obtain the corresponding total effective anti-reflection bandwidth EAB; Step 4: In the finite element analysis software, establish a characteristic calculation model of the chiral origami honeycomb, calculate the model calculation sample, and obtain the corresponding equivalent stiffness E and equivalent density Density. Step 5: Calculate the sample and its corresponding total effective anti-reflection bandwidth EAB, equivalent stiffness E, and equivalent density Density using the model, and establish an approximate calculation model of EAB-E-Density for chiral origami honeycomb. Step 6: With the goal of maximizing the total effective anti-reflection bandwidth EAB, constrain the equivalent stiffness E and equivalent density Density. Using the EAB-E-Density approximation calculation model, calculate the total effective anti-reflection bandwidth EAB, equivalent stiffness E, and equivalent density Density of the chiral origami honeycomb. Optimize within the range of design parameter values ​​to obtain the optimized design parameters.

2. The chiral origami honeycomb optimization design method according to claim 1, characterized in that, In step one, the design parameters for the chiral origami honeycomb include the side length R1 of the large regular hexagons at both ends, the side length R2 of the small regular hexagon in the middle, the twist angle φ between the large regular hexagons at both ends and the small regular hexagon in the middle, and the wall thickness t.

3. The chiral origami honeycomb optimization design method according to claim 2, characterized in that, In step one, the side length R1 of the two large regular hexagons is determined to be in the range of 3 mm to 6 mm, the side length R2 of the middle small regular hexagon is determined to be in the range of 2 mm to 6 mm, the torsion angle φ between the two large regular hexagons and the middle small regular hexagon is determined to be in the range of -60° to 60°, the wall thickness t is determined to be in the range of 0.4 mm to 1 mm, and R2 ≤ R1.

4. The chiral origami honeycomb optimization design method according to claim 3, characterized in that, In step two, within the range of chiral origami honeycomb design parameters, optimal Latin hypercube sampling is performed, and model calculation samples are selected.

5. The chiral origami honeycomb optimization design method according to claim 4, characterized in that, In step five, constraints are imposed on the equivalent stiffness E and the equivalent density Density, specifically as follows: E> E_0; Density ≤ Density _0; in, E_0 is the constraint value of the equivalent stiffness, which is taken as 1200MPa; Density _0 is the constraint value for the equivalent density, which is taken as 500 kg / m³.

6. The chiral origami honeycomb optimization design method according to claim 5, characterized in that, In step five, a multi-island genetic algorithm is used to find the optimal design parameters within the range of chiral origami honeycomb design parameters.

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