A neutral surface construction method for spatial interpolation of aircraft wing strain data

Abstract

The present application belongs to the technical field of strain data processing in a ground strength test of an aircraft wing, and specifically relates to a neutral surface construction method for spatial interpolation of strain data of an aircraft wing, comprising: step one, extracting nodes of an upper wing surface and a lower wing surface; step two, using the extracted nodes of the upper wing surface and the lower wing surface to generate multiple groups of spatial discrete points located between the upper wing surface and the lower wing surface; step three, from the multiple groups of spatial discrete points, selecting a group with the smallest distance deviation from the upper wing surface and the lower wing surface as a neutral surface fitting point; step four, dividing the neutral surface fitting point into multiple segments according to the curvature of the upper wing surface and the lower wing surface; step five, fitting the neutral surface fitting points of each segment to obtain multiple fitting surfaces; step six, splicing the various fitting surfaces to obtain a neutral surface.

Description

Technical Field

[0001] The present application belongs to the technical field of strain data processing for aircraft wing ground strength test, and in particular relates to a neutral surface construction method for spatial interpolation of aircraft wing strain data. Background Art

[0002] During ground testing of aircraft wings, a large number of strain gauges are attached to the upper and lower wing surfaces to measure, monitor and record the strain data on the wing surface to assist in test decision-making.

[0003] Traditionally, the analysis of wing surface strain mostly records the position coordinates of strain gauges attached to the upper and lower surfaces of the wing on a two-dimensional plane and displays the corresponding measured data. This technical solution is difficult to present the strain distribution on the wing surface intuitively and in real time, and cannot effectively assist in experimental decision-making.

[0004] With the development of computer-aided testing technology, technicians can display the strain measurement data on the digital prototype model of the wing during the test, thereby presenting the strain distribution on the wing surface intuitively and in real time. This greatly facilitates the technicians' analysis of the strain distribution on the wing surface and improves the efficiency of auxiliary test decision-making.

[0005] However, the strain measurement data is only displayed on the wing digital prototype model, and the amount of data is relatively limited. In order to improve the utilization of the strain measurement data, the design performs spatial interpolation on the strain measurement data and uses the neutral surface for spatial interpolation of the strain measurement data. The specific implementation is as follows:

[0006] Construct a neutral surface between the upper and lower wing surfaces, and construct a mesh on the neutral surface;

[0007] The strain measurement data on the upper and lower wing surfaces are projected onto the neutral plane, and interpolation calculations are performed on the neutral plane according to the grid nodes;

[0008] The strain data is obtained by interpolation calculation on the neutral plane and back-projected onto the upper and lower surfaces of the wing for display.

[0009] Currently, when the neutral surface is used for spatial interpolation of wing strain measurement data, the neutral surface used is mostly a planar neutral surface, such as Figure 1 As shown in the figure, the distance between this neutral plane and the upper and lower wing surfaces is different, and it will interfere with the upper and lower wing surfaces, which seriously affects the calculation accuracy of the spatial interpolation of the wing strain measurement data.

[0010] This application is proposed in view of the above-mentioned technical defects. Summary of the invention

[0011] The purpose of the present application is to provide a neutral surface construction method for spatial interpolation of aircraft wing strain data, so as to overcome or alleviate at least one aspect of the known technical defects.

[0012] The technical solution of this application is:

[0013] A neutral surface construction method for spatial interpolation of aircraft wing strain data, comprising:

[0014] Step 1, extracting nodes of the upper wing surface and the lower wing surface;

[0015] Step 2: using the extracted nodes of the upper wing surface and the lower wing surface, generate multiple groups of spatial discrete points between the upper wing surface and the lower wing surface;

[0016] Step 3: From multiple groups of spatial discrete points, select the group with the smallest distance deviation from the upper wing surface and the lower wing surface as the neutral plane fitting point;

[0017] Step 4: Divide the neutral plane fitting points into multiple segments according to the curvature of the upper wing surface and the lower wing surface;

[0018] Step 5: Fit the fitting points of each segment of the neutral surface to obtain multiple fitting surfaces;

[0019] Step 6: Connect the various fitting surfaces to obtain the neutral surface.

[0020] Optionally, in the above-mentioned neutral surface construction method for spatial interpolation of aircraft wing strain data, in step one, all nodes of the upper wing surface and the lower wing surface are extracted, or some nodes of the upper wing surface and the lower wing surface are extracted.

[0021] Optionally, in the above-mentioned neutral surface construction method for spatial interpolation of aircraft wing strain data, in step three, the least squares method is used to calculate, and from multiple groups of spatial discrete points, the group with the smallest distance deviation from the upper wing surface and the lower wing surface is selected as the neutral surface fitting point.

[0022] Optionally, in the above-mentioned neutral surface construction method for spatial interpolation of aircraft wing strain data, in step 4, the neutral surface fitting points are divided into three sections corresponding to the wing root area, the wing mid-area, and the wing tip area.

[0023] Optionally, in the above-mentioned neutral surface construction method for spatial interpolation of aircraft wing strain data, in step five, the Lagrangian algorithm or the Euler algorithm is used to fit the fitting points of each segment of the neutral surface to obtain multiple fitting surfaces.

[0024] Optionally, the neutral surface construction method for spatial interpolation of aircraft wing strain data further includes:

[0025] Step 7: Determine whether the neutral surface is smooth and continuous. If not, correct the neutral surface to make it smooth and continuous.

[0026] Optionally, in the above-mentioned neutral surface construction method for spatial interpolation of aircraft wing strain data, in step seven, the partial derivative of the neutral surface is obtained, and by judging the continuity of the partial derivative, it is judged whether the neutral surface is smooth and continuous;

[0027] The neutral surface is corrected to make it smooth and continuous, which is achieved by re-extracting the nodes of the upper wing surface and the lower wing surface and repeating steps 2 to 7, or correcting the non-smooth and continuous areas.

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

[0029] Provided is a neutral surface construction method for spatial interpolation of aircraft wing strain data. The method is designed to utilize nodes of an upper wing surface and a lower wing surface to generate multiple groups of spatial discrete points located between the upper wing surface and the lower wing surface, and select a group with the smallest distance deviation from the upper wing surface and the lower wing surface as the neutral surface fitting point. The group is divided into multiple sections according to the curvature of the upper wing surface and the lower wing surface, and fitting is performed. The obtained multiple fitting surfaces are spliced ​​to obtain a neutral surface. The neutral surface is a curved surface, has a small distance deviation from the upper wing surface and the lower wing surface, is consistent with the curvature of the upper wing surface and the lower wing surface, and does not interfere with the upper wing surface and the lower wing surface. The wing strain measurement data is spatially interpolated by the neutral surface, and the calculation accuracy can be effectively guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the existing method of using a plane neutral plane to perform spatial interpolation on the wing strain measurement data;

[0031] Figure 2 is a schematic diagram of a neutral surface construction method for spatial interpolation of aircraft wing strain data provided in an embodiment of the present application;

[0032] Figure 3 It is a schematic diagram of a curved surface neutral surface constructed by using a neutral surface construction method for spatial interpolation of aircraft wing strain data provided in an embodiment of the present application.

[0033] In order to better illustrate the present embodiment, some contents of the drawings may be omitted, enlarged or reduced, which is only used for illustrative purposes and should not be construed as limiting the present application. DETAILED DESCRIPTION

[0034] In order to make the technical solution and advantages of the present application clearer, the technical solution of the present application will be described in further detail in detail and in detail with reference to the accompanying drawings. It can be understood that the specific embodiments described here are only partial embodiments of the present application, which are only used to explain the present application, not to limit the present application. It should be noted that, for the convenience of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design.

[0035] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of this application should be the common meanings understood by those skilled in the art in the field to which this application belongs. The term "include" used in the description of this application means that the concepts appearing before the term include the concepts listed after the term and their equivalents, without excluding other related concepts.

[0036] A neutral surface construction method for spatial interpolation of aircraft wing strain data, such as Figure 1 shown.

[0037] Step 1: Extract the nodes of the upper and lower wing surfaces.

[0038] All nodes or part of the nodes of the upper wing surface and the lower wing surface can be extracted. When the performance of the relevant equipment allows, all nodes of the upper wing surface and the lower wing surface can be extracted. In order to ensure calculation efficiency, only part of the nodes of the upper wing surface and the lower wing surface can be extracted.

[0039] Step 2: Using the extracted nodes of the upper wing surface and the lower wing surface, generate multiple groups of spatial discrete points between the upper wing surface and the lower wing surface.

[0040] Step 3: From multiple groups of spatial discrete points, select the group with the smallest distance deviation from the upper wing surface and the lower wing surface as the neutral plane fitting point.

[0041] Specifically, the least square method can be used for calculation, and from multiple groups of spatial discrete points, the group with the smallest distance deviation from the upper wing surface and the lower wing surface is selected as the neutral surface fitting point.

[0042] Step 4: Divide the neutral plane fitting points into multiple segments according to the curvature of the upper wing surface and the lower wing surface.

[0043] Specifically, the neutral plane fitting points in the area where the curvatures of the upper and lower wing surfaces are close can be divided into one section. In practice, the neutral plane fitting points can usually be divided into three sections, corresponding to the wing root area, the wing middle area, and the wing tip area, respectively.

[0044] Step 5: Fit the fitting points of each segment of the neutral surface to obtain multiple fitting surfaces.

[0045] Specifically, the Lagrange algorithm, the Euler algorithm or other feasible algorithms can be used to fit the fitting points of each segment of the neutral surface to obtain multiple fitting surfaces.

[0046] According to the curvature of the upper and lower wing surfaces, the neutral surface fitting points are divided into multiple segments and fitted separately. On the one hand, the difficulty of surface fitting can be reduced. On the other hand, the conformity of the fitting surface with the curvature of the upper and lower wing surfaces can be ensured, so that the obtained neutral surface is consistent with the curvature of the upper and lower wing surfaces, thereby ensuring the accuracy of spatial interpolation of strain measurement data.

[0047] Step 6: Connect the various fitted surfaces to obtain a neutral surface, which is a curved surface.

[0048] Step 7: Determine whether the neutral surface is smooth and continuous. If not, correct the neutral surface to make it smooth and continuous.

[0049] Since the neutral surface is composed of multiple fitting surfaces, there are bends at the splicing boundaries, that is, it is not smooth and continuous. The existence of such parts will cause the spatial interpolation of the strain measurement data, and there will be obvious mutations on the upper and lower wing surfaces. Therefore, it is necessary to judge whether the obtained neutral surface is smooth and continuous. If it is not smooth and continuous, the neutral surface needs to be further corrected to make it smooth and continuous.

[0050] To determine whether the neutral surface is smooth and continuous, the partial derivative of the neutral surface can be obtained. By determining the continuity of the partial derivative, it can be determined whether the neutral surface is smooth and continuous. If the partial derivative is discontinuous, it is considered that the neutral surface is not smooth and continuous.

[0051] The neutral surface is corrected to make it smooth and continuous. This can be achieved by re-extracting the nodes of the upper wing surface and the lower wing surface and repeating steps 2 to 7. It can also be achieved by only correcting the non-smooth and continuous areas.

[0052] The neutral surface construction method for spatial interpolation of aircraft wing strain data disclosed in the above embodiment can be performed in the overall coordinate system of the aircraft and constructed with the overall coordinate system of the aircraft as a reference. In a specific example, the neutral surface constructed is as follows: Figure 3 shown.

[0053] In the neutral surface construction method for spatial interpolation of aircraft wing strain data disclosed in the above embodiment, the nodes of the upper wing surface and the lower wing surface are designed to generate multiple groups of spatial discrete points located between the upper wing surface and the lower wing surface, and the group with the smallest distance deviation from the upper wing surface and the lower wing surface is selected as the neutral surface fitting point, and is divided into multiple sections according to the curvature of the upper wing surface and the lower wing surface, and fitting is performed. The multiple fitting surfaces obtained are spliced ​​to obtain the neutral surface. The neutral surface is a curved surface with a small distance deviation between the upper wing surface and the lower wing surface, and is consistent with the curvature of the upper wing surface and the lower wing surface, and will not interfere with the upper wing surface and the lower wing surface. The wing strain measurement data is spatially interpolated with it, which can effectively ensure the calculation accuracy.

[0054] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the scope of protection of the present application.

Claims

1. A neutral surface construction method for spatial interpolation of aircraft wing strain data, characterized in that: include: Step 1, extracting nodes of the upper wing surface and the lower wing surface; Step 2: using the extracted nodes of the upper wing surface and the lower wing surface, generate multiple groups of spatial discrete points between the upper wing surface and the lower wing surface; Step 3: From multiple groups of spatial discrete points, select the group with the smallest distance deviation from the upper wing surface and the lower wing surface as the neutral plane fitting point; Step 4: Divide the neutral plane fitting points into multiple segments according to the curvature of the upper wing surface and the lower wing surface; Step 5: Fit the fitting points of each segment of the neutral surface to obtain multiple fitting surfaces; Step 6: Connect the various fitting surfaces to obtain the neutral surface.

2. The neutral surface construction method for spatial interpolation of aircraft wing strain data according to claim 1, characterized in that: In step 1, all nodes of the upper wing surface and the lower wing surface are extracted, or some nodes of the upper wing surface and the lower wing surface are extracted.

3. The neutral surface construction method for spatial interpolation of aircraft wing strain data according to claim 2, characterized in that: In step three, the least squares method is used to calculate and select the group with the smallest distance deviation from the upper wing surface and the lower wing surface from multiple groups of spatial discrete points as the neutral surface fitting point.

4. The neutral surface construction method for spatial interpolation of aircraft wing strain data according to claim 3 is characterized in that: In step 4, the neutral surface fitting points are divided into three sections corresponding to the wing root area, the wing mid-area, and the wing tip area.

5. The neutral surface construction method for spatial interpolation of aircraft wing strain data according to claim 4, characterized in that: In step five, the Lagrangian algorithm or the Euler algorithm is used to fit the fitting points of each segment of the neutral surface to obtain multiple fitting surfaces.

6. The neutral surface construction method for spatial interpolation of aircraft wing strain data according to claim 5, characterized in that: Also includes: Step 7: Determine whether the neutral surface is smooth and continuous. If not, correct the neutral surface to make it smooth and continuous.

7. The neutral surface construction method for spatial interpolation of aircraft wing strain data according to claim 6, characterized in that: In step 7, the partial derivative of the neutral surface is obtained, and by judging the continuity of the partial derivative, it is determined whether the neutral surface is smooth and continuous; The neutral surface is corrected to make it smooth and continuous, which is achieved by re-extracting the nodes of the upper wing surface and the lower wing surface and repeating steps 2 to 7, or correcting the non-smooth and continuous areas.

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