CN113032892B - Skin panel parameter optimization method based on stability algorithm - Google Patents

Abstract

The invention discloses a skin panel parameter optimization method based on a stability algorithm, which comprises the following steps: step 1, calculating equivalent stress and critical buckling stress of a skin unit according to an initial model of a skin panel structure of a metal wing, and calculating a stress ratio of the skin unit; step 2, when the stress ratio of the skin unit is greater than or equal to 1, setting a thickness increasing coefficient for increasing the thickness of the skin unit; and 3, determining to adopt the thickness increasing coefficient or the minimum amount of the skin thickness processing technology to carry out thickness increasing treatment on the skin units according to the comparison of the thickness increasing amount formed by the skin units by adopting the thickness increasing coefficient set in the step 2 and the minimum amount of the skin thickness processing technology. The embodiment of the invention solves the problems that the traditional skin panel parameter optimization method highly depends on the experience of designers and has huge manual parameter adjustment workload because the stability is only checked and does not participate in initiative in the parameterization process of the traditional skin panel.

Description

A Stability Algorithm-Based Parameter Optimization Method for Skin Panels

technical field

The invention relates to, but is not limited to, the technical field of aircraft structure design and strength analysis, in particular to a method for optimizing skin panel parameters based on a stability algorithm.

Background technique

In the process of traditional aircraft metal wing skin panel parameter optimization, the optimization idea is as follows: the thickness parameter of the skin panel is used as the optimization variable, and the full stress level is the constraint condition under the constraints of the manufacturing process, and then the stability of the panel is checked. , the final optimization goal is to minimize the weight of the siding.

In the above method of optimizing the panel parameters, the panel stability is only used as a passive strength check, not as an active design reference; and the existing parameterization process can only manually modify the thickness parameters of a single element that does not meet the stability requirements. , the change basis needs strong experience, completely depends on the subjective experience of the designer, and the workload of parameter adjustment is large.

SUMMARY OF THE INVENTION

The purpose of the present invention is as follows: the embodiment of the present invention provides a method for optimizing the parameters of the skin panel based on the stability algorithm, so as to solve the problem that in the process of parameterization of the traditional skin panel, the stability is only checked and does not participate in the initiative. This makes the traditional skin panel parameter optimization method highly dependent on the designer's experience and the huge workload of manual parameter adjustment.

The technical solution of the present invention is as follows: the embodiment of the present invention provides a method for optimizing the parameters of a skin panel based on a stability algorithm, including:

Step 1, according to the initial model of the metal wing skin panel structure, calculate the equivalent stress σ and the critical instability stress σ _c of the skin element, and calculate the stress ratio σ/σ _c of the skin element;

Step 2, when the stress ratio σ/σ _c of the skin unit is greater than or equal to 1, set a thickness increase coefficient for increasing the thickness of the skin unit;

Step 3, according to the comparison between the thickness increase amount formed by the thickness increase coefficient set in step 2 and the minimum amount of the skin thickness processing technology for the skin unit, determine to use the thickness increase coefficient or skin thickness processing The skin element is thickened with a minimum amount of process.

Optionally, in the above-mentioned method for optimizing the parameters of the skin panel based on the stability algorithm, the method for setting the thickness increase coefficient in the step 2 is:

Set the thickness increase factor to (σ/σ _c ) ^1/3 ; where, for each individual skin element, after the thickness is increased by (σ/σ _c ) ^1/3 , the equivalent stress σ of the corresponding skin element is equal to Critical buckling stress σ _c .

Optionally, in the above-mentioned method for optimizing the parameters of the skin panel based on the stability algorithm, the method for obtaining the thickness increase of the skin unit in the step 3 is:

Step 31: Calculate the thickness increase amount ((σ/σ _c ) ^1/3 -1)t formed by increasing the thickness of the skin unit by using the thickness increase coefficient (σ/σ _c ) ^1/3 ; wherein, t is the wall thickness of the skin unit.

Optionally, in the above-mentioned method for optimizing the parameters of the skin panel based on the stability algorithm, in the step 3, the method of increasing the thickness of the skin unit is determined, including:

Step 32, determine whether the thickness increase is greater than or equal to 0.2mm, and 0.2mm is the minimum amount of the skin thickness processing technology;

Step 33, when the thickness increase is greater than or equal to 0.2 mm, use the thickness increase coefficient to increase the thickness of the skin unit;

Step 34 , when the thickness increase amount is less than 0.2 mm, increase the thickness of the skin unit by taking 0.2 mm as the thickness increase amount.

Optionally, in the above-mentioned method for optimizing the parameters of the skin panel based on the stability algorithm, the method of increasing the thickness of the skin unit by using the thickness increase coefficient in the step 33 includes:

An acceleration factor k is set for the thickness increase coefficient, the thickness increase coefficient (σ ^/ σ _{c )} ^1/3 is amplified by k times by the acceleration factor k, and the The thickness of the skin element is increased.

Optionally, in the above-mentioned method for optimizing the parameters of the skin panel based on the stability algorithm, the method further includes:

Step 4, by repeating steps 2 to 3 to increase the thickness of the skin element, specifying that the stress ratio σ/σ _c of the skin element is less than 1.

Optionally, in the above-mentioned method for optimizing the parameters of the skin panel based on the stability algorithm, the value of the acceleration factor k is between 1 and 2;

In the process of performing step 2 to step 3 each time in the method for optimizing the parameters of the skin panel, by setting the value of the acceleration factor k, the thickness increase of the skin unit is adjusted, so as to adjust the optimization of the parameters of the skin panel. speed.

Optionally, in the above-mentioned method for optimizing the parameters of the skin panel based on the stability algorithm, the method further includes:

Step 2a, when the stress ratio σ/ _σc of the skin element is less than 1, the corresponding skin element conforms to the stability control, and the optimization ends.

The beneficial effects of the present invention are: compared with the traditional method for optimizing the parameters of the skin panel of a metal wing, the embodiment of the present invention provides a method for optimizing the parameters of the skin panel based on the stability algorithm. Engineering experience proposes an accelerated optimization method for skin panel parameters, creatively deduces stability check control as stability active design, and the derived increase coefficient points out the optimization direction for panel parameter optimization stability control; another On the one hand, the setting of the acceleration factor greatly reduces the number of optimization iterations, shortens the manual adjustment work of traditional optimization methods from several hours to several minutes, and greatly improves the optimization efficiency. The skin panel parameter optimization method based on the stability algorithm provided by the embodiment of the present invention introduces the stability design as an active design factor into the optimization process, designs the accelerated iteration coefficient, and realizes the rapid optimization of parameters. .

Description of drawings

The accompanying drawings are used to provide a further understanding of the technical solutions of the present invention, and constitute a part of the specification. They are used to explain the technical solutions of the present invention together with the embodiments of the present application, and do not limit the technical solutions of the present invention.

1 is a flowchart of a method for optimizing skin panel parameters based on a stability algorithm according to an embodiment of the present invention;

FIG. 2 is a flowchart of another method for optimizing parameters of a skin panel based on a stability algorithm according to an embodiment of the present invention.

specific embodiment

In order to make the objectives, technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, the embodiments in the present application and the features in the embodiments may be arbitrarily combined with each other if there is no conflict.

It has been explained in the above background art that the stability of the panel is only used as a passive strength check function, rather than as an active design reference; and the existing parameterization process can only manually modify the thickness parameters of a single unit that does not meet the stability. Changes are based on strong experience, completely relying on the subjective experience of designers, and the workload of parameter adjustment is large.

Based on the above problems, embodiments of the present invention provide a skin panel parameter optimization method based on a stability algorithm, which incorporates stability design as an active design factor into the optimization process, designs accelerated iteration coefficients, and realizes rapid parameter optimization.

The present invention provides the following specific embodiments that can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments.

FIG. 1 is a flowchart of a method for optimizing parameters of a skin panel based on a stability algorithm according to an embodiment of the present invention. The skin panel parameter optimization method based on the stability algorithm provided by the embodiment of the present invention may include the following steps:

Step 1, according to the initial model of the metal wing skin panel structure, calculate the equivalent stress σ and critical instability stress σ _c of the skin element, and calculate the stress ratio σ/σ _c of the skin element;

Step 2, when the stress ratio σ/σ _c of the skin element is greater than or equal to 1, set a thickness increase coefficient for increasing the thickness of the skin element;

Step 3: According to the comparison between the thickness increase amount formed by the skin unit using the thickness increase coefficient set in step 2 and the minimum amount of the skin thickness processing technology, determine the thickness increase coefficient or the minimum amount of the skin thickness processing technology. Increase the thickness of the skin elements.

In step 2 of the embodiment of the present invention, the implementation manner of setting the thickness increase coefficient is as follows:

Set the thickness increase factor to (σ/σ _c ) ^1/3 ; where, for each individual skin element, after the thickness is increased by (σ/σ _c ) ^1/3 , the equivalent stress σ of the corresponding skin element is equal to Critical buckling stress σ _c .

The implementation manner of obtaining the thickness increase of the skin unit in step 3 of the embodiment of the present invention includes:

Step 31: Calculate the thickness increase amount ((σ/σ _c ) ^1/3 -1)t formed by increasing the thickness of the skin element by using the thickness increase coefficient (σ/σ _c ) ^1/3 ; where t is The thickness of the siding of the skinned element.

In the step 3 of the embodiment of the present invention, the implementation manner of determining to increase the thickness of the skin unit includes:

Step 32, determine whether the thickness increase is greater than or equal to 0.2mm, and 0.2mm is the minimum amount of the skin thickness processing technology;

Step 33, when the thickness increase is greater than or equal to 0.2mm, use the thickness increase coefficient to increase the thickness of the skin unit;

Step 34 , when the thickness increase is less than 0.2 mm, the thickness of the skin unit is increased by taking 0.2 mm as the thickness increase.

In step 33 of the embodiment of the present invention, the method of increasing the thickness of the skin unit by the thickness increase coefficient includes:

The acceleration factor k is set for the thickness increase factor, the thickness increase factor (σ/σ _c ) ^1/3 is amplified by k times through the acceleration factor k, and the thickness of the skin element is increased by k(σ/σ _c ) ^1/3 . Increase; in the embodiment of the present invention, the acceleration factor k is set to reduce the number of iterations for parameter optimization of the skin panel.

The skin panel parameter optimization method provided by the embodiment of the present invention may further include the following steps:

Step 4, by repeating steps 2 to 3, the thickness of the skin element is increased, and the stress ratio σ/σ _c of the specified skin element is less than 1.

It should be noted that the value of the acceleration factor k in the embodiment of the present invention is between 1 and 2; in addition, the parameter optimization method of the skin panel sets the acceleration factor during each execution of steps 2 to 3. The value of k adjusts the thickness increase of the skin unit, thereby adjusting the speed of the optimization of the parameters of the skin panel.

The skin panel parameter optimization method provided by the embodiment of the present invention may further include the following steps:

Step 2a, when the stress ratio σ/ _σc of the skin element is less than 1, the corresponding skin element conforms to the stability control, and the optimization ends.

Compared with the traditional metal wing skin panel parameter optimization method, the skin panel parameter optimization method based on the stability algorithm provided by the embodiment of the present invention, on the one hand, combines theory and engineering experience to propose a skin panel parameter optimization method. The acceleration optimization method creatively deduces the stability check control as the stability active design, and the derived increase coefficient points out the optimization direction for the optimization stability control of the panel parameters; on the other hand, the setting of the acceleration factor greatly affects The number of optimization iterations is reduced, and the manual adjustment work of traditional optimization methods is shortened from several hours to several minutes, which greatly improves the optimization efficiency. The skin panel parameter optimization method based on the stability algorithm provided by the embodiment of the present invention introduces the stability design as an active design factor into the optimization process, designs the accelerated iteration coefficient, and realizes the rapid optimization of parameters.

The derivation method of the thickness increase coefficient (σ/σ _c ) ^1/3 in the embodiment of the present invention will be described below.

Before using the method provided by the embodiment of the present invention for optimization, let the equivalent stress be σ ₀ , the critical buckling stress σ _c0 , and the equivalent stress σ ₀ satisfies the following relationship:

Among them, F is the compressive load of the skin element, b is the width of the loaded edge of the skin element; the equivalent stress σ ₀ and the critical buckling stress σ _c0 satisfy the following relationship:

In the above formula, K _c is the compressive critical stress coefficient, E is the elastic model of the material, and μ is the elastic Poisson's ratio of the material.

Assuming that the thickness of the skin element is increased by X times, the theoretical equivalent stress of the skin element is equal to the critical buckling stress, and the optimized equivalent stress is σ ₁ , and the critical buckling stress is σ _c1 , according to the formula:

σ _c1 =σ _c0 *X ² ;

It can be deduced that the two are equal:

X=(σ ₀ /σ _c0 ) ^1/3 .

The specific implementation of the method for optimizing the parameters of the skin panel based on the stability algorithm provided by the embodiment of the present invention will be described in detail below through an implementation example.

As shown in FIG. 1, it is a method for optimizing the parameters of a skin panel based on a stability algorithm provided by an embodiment of the present invention. FIG. 1 is a flowchart of a method for fast attribute mapping from a CAD model to a CAE model. In this implementation example, the skin The specific realization principle of the panel parameter optimization method is as follows:

1. For the initial model of the metal wing skin panel structure, in the parameter optimization process, the skin thickness t is selected as the optimization variable, and the equivalent stress σ of the skin cell is calculated. According to the full stress and stability constraints, the present invention The emphasis is on stability control and stability feedback design, calculating the critical buckling stress σ _c of the skin cell, and judging the ratio σ/σ _c ;

2. If the above ratio σ/σ _c is less than 1, it means that the skin unit meets the stability control, meets the design requirements, and the optimization ends;

3. If the above ratio σ/σ _c is greater than or equal to 1, it means that the skin element will be unstable, the skin element needs to be thickened, and the design thickness increase factor (σ/σ _c ) ^1/3 ;

It should be noted that the design principle of the increase factor is that the equivalent stress σ∝t ^-1 , the critical instability stress σ _c ∝t ² (known formula), theoretically, for each individual skin element, the thickness increases After increasing (σ/σ _c ) ^1/3 , the equivalent stress σ of the skin element is equal to the critical buckling stress σ _c ;

4. Considering the manufacturing process, determine whether the thickness increase ((σ/σ _c ) ^1/3 -1)t is greater than or equal to 0.2mm, if it is greater than or equal to 0.2mm, it can be increased according to step 3, if it is less than 0.2 When it is mm, it is increased by 0.2mm; the minimum amount of skin thickness processing technology in the manufacturing process of this step;

5. In the actual optimization process, in order to speed up the optimization process of the parameters of the skin panel, the acceleration factor k can be designed, and the (σ ^/ σ _{c )} ^1/3 is enlarged by k times, and the The thickness of the pico elements is increased, which greatly reduces the number of iterations.

The following describes the implementation of the optimization using the acceleration factor in the embodiment of the present invention. As shown in FIG. 2, it is a flowchart of another method for optimizing the parameters of the skin panel based on the stability algorithm provided by the embodiment of the present invention. This process specifically illustrates the influence of the setting of the acceleration factor k on the process.

Set the initial optimization stage, k is 1;

The number of iterations is 0: calculate the number of skin cells m that the initial module does not meet the stability control;

The number of iterations is 1: calculate the number n of skin cells that do not meet the stability control after the first optimization;

If n/m is greater than m ^-0.125 , it is considered that the optimization cannot be completed after 8 iterations, then the acceleration factor k is set, and the value is in the interval (1, 2) depending on the optimization accuracy requirements. The larger the value, the faster the optimization speed. The lower the optimization precision.

Although the embodiments disclosed in the present invention are as above, the described contents are only the embodiments adopted to facilitate the understanding of the present invention, and are not intended to limit the present invention. Any person skilled in the art to which the present invention belongs, without departing from the spirit and scope disclosed by the present invention, can make any modifications and changes in the form and details of the implementation, but the scope of the patent protection of the present invention still needs to be The scope defined by the appended claims shall prevail.

Claims (3)

1. A skin panel parameter optimization method based on a stability algorithm is characterized by comprising the following steps:

step 1, calculating the equivalent stress sigma and the critical instability stress sigma of a skin unit according to an initial model of a skin panel structure of a metal wing _c And calculating the stress ratio sigma/sigma of the skin unit _c ；

Step 2, stress ratio sigma/sigma of the skin unit _c When the thickness of the skin unit is greater than or equal to 1, setting a thickness increasing coefficient for increasing the thickness of the skin unit;

step 3, determining that the thickness increasing coefficient or the minimum amount of the skin thickness processing technology is used for performing thickness increasing treatment on the skin unit according to the comparison between the thickness increasing amount formed by the skin unit and the minimum amount of the skin thickness processing technology by using the thickness increasing coefficient set in the step 2;

step 4, the thickness of the skin units is increased by repeatedly executing the steps 2 to 3, and the stress ratio sigma/sigma of the skin units is specified _c Less than 1;

wherein, the thickness increasing coefficient is set in the step 2 in a manner that:

setting the thickness increase coefficient to (sigma/sigma) _c ) ^1/3 (ii) a Wherein the thickness increases (σ/σ) for each individual skin cell _c ) ^1/3 Then, the equivalent stress σ of the corresponding skin unit is equal to the critical buckling stress σ _c ；

The manner of obtaining the thickness increase amount of the skin unit in the step 3 is as follows:

step 31, calculating the thickness increase coefficient (sigma/sigma) _c ) ^1/3 An increased thickness amount ((sigma/sigma) formed by increasing the thickness of the skin unit _c ) ^1/3 -1) t; wherein t is the thickness of the wall plate of the skin unit;

determining a thickness increasing mode of the skin unit in the step 3 includes:

step 32, judging whether the thickness increase is greater than or equal to 0.2mm, wherein 0.2mm is the minimum amount of the skin thickness processing technology;

step 33, when the thickness increase is greater than or equal to 0.2mm, adopting the thickness increase coefficient to increase the thickness of the skin unit;

step 34, when the thickness increment is smaller than 0.2mm, the thickness increment is carried out on the skin unit by taking 0.2mm as the thickness increment;

in the step 33, the increasing the thickness of the skin unit by using the thickness increase coefficient includes:

setting an acceleration factor k to the thickness increasing coefficient by which the thickness increasing coefficient (σ/σ) is increased _c ) ^1/3 Amplifying by k times and passing k (sigma/sigma) _c ) ^1/3 And increasing the thickness of the skin unit.

2. The stability algorithm-based skin panel parameter optimization method of claim 1, wherein the acceleration factor k has a value between 1 and 2;

in the process of executing the steps 2 to 3 each time, the skin panel parameter optimization method adjusts the thickness increase amount of the skin unit by setting the value of the acceleration factor k, so that the skin panel parameter optimization speed is adjusted.

3. The stability algorithm-based skin panel parameter optimization method of claim 1, further comprising:

step 2a, stress ratio sigma/sigma of the skin unit _c When less than 1, the corresponding maskAnd (5) the skin unit accords with stability control, and optimization is finished.

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