Virtual test method and system for evaluating static strength of airborne external stores

Abstract

The present application relates to the technical field of virtual and real combined simulation test, and discloses a virtual test method and system for evaluating the static strength of airborne external stores, which is used to replace physical static test to realize efficient, low-cost and reliable static strength evaluation. The method comprises the following steps: modifying an ideal finite element model according to deviation information to obtain a finite element model of the airborne external stores for a virtual static test system; using a virtual material method to equivalently process the contact stiffness between the finite element model of the airborne external stores and the finite element model of a test fixture; selecting sampling points for the virtual static test within a gap range, and fitting a three-dimensional mapping relationship among the sleeve joint depth gap, load and maximum strain or maximum displacement according to the sampling data of the virtual simulation; performing an actual static test and checking the three-dimensional mapping relationship to obtain the sleeve joint depth gap of the actual test environment, and then obtaining the final virtual parameters of the equivalent assembly error of the thin layer element in the virtual material method for subsequent virtual static test system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of virtual-real combined simulation test, and in particular to a virtual test method and system for static strength evaluation of airborne external stores. BACKGROUND

[0002] Airborne external stores refer to objects hung on aircraft and play a very important role in various mission profiles of the aircraft. With the upgrading of modern mission scenarios, higher requirements are put forward for the functional diversity of airborne external store products and the rapid development and iteration of products. In response to the requirements of the times, modularization and serialization have become one of the mainstream trends in the development of modern airborne external stores. Modularized and serialized airborne external store products have the need to be assembled with multiple models, and therefore the products need to face more complex and diversified service task load environments. In order to ensure the structural safety and reliability of the products under various complex load conditions, multiple static tests are usually required to verify the structural static strength reliability of the products under different models and load conditions.

[0003] However, the traditional physical static test method has two defects: first, during the static test process, only a limited number of strain and displacement sensors can be used to obtain the local mechanical response of the product, and the full-field mechanical response of the tested product cannot be obtained in real time. For the positions where the sensors are limited to install on the product, the response information cannot be obtained, which may lead to the failure to collect the mechanical response of the high-risk area (high strain and high displacement area) of the product and to timely discover the local failure of the product; second, due to the complex and diverse load conditions of modularized and serialized products, the number of static test rounds of the products is significantly increased, which leads to long test cycle and high test cost of the physical static test, and seriously affects the product development efficiency.

[0004] With the development of new generation information technology and the improvement of virtual simulation modeling technology, virtual test technology and virtual-real combined test technology have been developed and have become an important static test verification tool. However, the existing virtual test technology focuses on improving the refinement and intelligence of physical static test, mainly applied to checking whether the physical static test tool design is reasonable, and visualizing the test mechanical response and other auxiliary functions, lacks research and methods for improving the fidelity and accuracy of the virtual test system itself, and cannot replace the physical static test to perform high-fidelity static strength evaluation of the product, and cannot truly and effectively reduce the static test amount of modularized and serialized products. SUMMARY

[0005] The present application aims to disclose a virtual test method and system for static strength evaluation of airborne external stores to replace physical static test and achieve efficient, low-cost and reliable static strength evaluation.

[0006] To achieve the above-mentioned purpose, the virtual test method and system for static strength evaluation of airborne external stores disclosed by the present application comprises:

[0007] Step S1: Perform a topographic scan on the airborne external store test product to obtain noise-reduced source point cloud data. Align the source point cloud data with the target point cloud of the airborne external store physical finite element model using a three-dimensional rigid body transformation matrix. Compare the aligned source point cloud data and target point cloud data to determine the deviation information of the airborne external store test product during the manufacturing process. Then, revise the physical finite element model according to the deviation information to obtain the airborne external store finite element model used in the virtual static test system.

[0008] Step S2: In the virtual static test system constructed based on the actual static test system, the contact stiffness between the finite element model of the airborne external attachment and the finite element model of the test clamp is equivalently represented by the virtual material method. The first virtual material parameters of the thin-layer unit between the finite element model of the airborne external attachment and the finite element model of the test clamp under ideal assembly conditions are obtained.

[0009] Step S3: Without applying a load to the actual static test system, measure the range of gaps caused by assembly errors in the fitting depth between the airborne external attachment and the test fixture.

[0010] Step S4: Select sampling points for the virtual static test within the gap range. Correct the first virtual material parameters of each sampling point according to the ratio between the actual fitting depth and the ideal fitting depth to obtain the second virtual parameters. Then, conduct virtual static tests based on each of the second virtual parameters to obtain the maximum strain or maximum displacement of the airborne external attachment under different loads. Finally, fit the sampling data to obtain the three-dimensional mapping relationship between the fitting depth gap, load, and maximum strain or maximum displacement. The actual fitting depth is the difference between the ideal fitting depth and the assembly gap.

[0011] Step S5: Conduct an actual static test. Based on the difference between the measured mechanical response data at the measurement points and the virtual test data, use RBF interpolation to correct the virtual mechanical response and obtain the maximum strain or maximum displacement of the measured environment under a specific load.

[0012] Step S6: Based on the three-dimensional mapping relationship, find the sleeve depth gap corresponding to the maximum strain or maximum displacement of the measured environment under a specific load. Then, based on the ratio between the actual sleeve depth and the ideal sleeve depth corresponding to the search result, correct the first virtual material parameters of each sampling point to obtain the final virtual parameters of the equivalent assembly error of the thin-layer unit for use in the subsequent virtual static test system.

[0013] Preferably, after step S6, the method further includes:

[0014] Step S7, performing a secondary actual static test, and determining whether the difference between the measured mechanical response data of the measuring points and the test data obtained from the virtual static test system after considering the equivalent assembly error of the thin layer unit is within the preset error range, if yes, confirming that the reliability of the virtual static test system meets the requirements, if no, outputting a notification to the user to return to step S4 after adjustment.

[0015] Preferably, the virtual static test system further comprises, after considering the equivalent assembly error of the thin layer unit:

[0016] The manufacturing tolerance of the airborne external object product is analyzed, and the finite element model is adjusted based on the upper limit or lower limit value of the tolerance to minimize the static strength.

[0017] Preferably, adjusting the finite element model based on the upper limit or lower limit value of the tolerance to minimize the static strength comprises reducing the wall thickness of the finite element model to the lower limit value of the tolerance and / or reducing the size of the inspection window in the finite element model to the upper limit value of the tolerance.

[0018] Preferably, the virtual material parameters of the thin layer unit include thickness, area, elastic modulus and shear modulus, and the formula for correcting the ideal virtual material parameters of each sampling point according to the ratio between the actual fitting depth and the ideal fitting depth is:

[0019] The thickness remains unchanged, and the area is times of the ideal case, wherein, is the ideal fitting depth, is the gap caused by the assembly error, and the elastic modulus and the shear modulus are times of the ideal case.

[0020] To achieve the above purpose, the present application further discloses a virtual test system for evaluating the static strength of an airborne external object, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor executes the computer program to realize the above method.

[0021] The present application has the following advantages:

[0022] The high-fidelity manufacturing deviation information is recorded in the finite element model of the airborne external object, and on the basis of the existing virtual material method, the sampling points of the virtual static test are selected in the gap range, then the first virtual material parameters of each sampling point are corrected to obtain the corresponding second virtual parameters under each gap according to the ratio between the actual joint depth and the ideal joint depth corresponding to the sampling points in the gap range, and then the three-dimensional mapping relationship among the joint depth gap, load and maximum strain or maximum displacement is fitted according to the sampling data of the virtual simulation; finally, the actual static test is carried out, and the joint depth gap of the measured environment is obtained by searching the three-dimensional mapping relationship, and then the final virtual parameters of the equivalent assembly error of the thin layer element in the virtual material method are obtained to be used for the subsequent virtual static test system. The logic of each step is echoed, and the many troubles caused by inaccurate assembly error measurement to the virtual static test are reliably solved, so that the static strength evaluation can be realized efficiently, at low cost and reliably instead of the physical static test.

[0023] The application will be described in further detail below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application, and are incorporated in and constitute a part of this application. The embodiments of the application illustrated in the drawings are used to explain the application and are not intended to limit the application. In the drawings:

[0025] Figure 1 is a schematic diagram of the virtual test method for static strength evaluation of the airborne external object according to the embodiment of the application. DETAILED DESCRIPTION

[0026] The embodiments of the application will be described in detail below with reference to the drawings, but the application can be implemented in various different ways limited and covered by the claims.

[0027] Embodiment 1

[0028] This embodiment takes a certain airborne external object adopting a cabin structure as an example for illustration, and discloses a virtual test method for static strength evaluation of the airborne external object, including the following steps:

[0029] Step 1: Establish a high-fidelity digital model of the airborne external object.

[0030] The specific implementation of this step can be as follows: First, calibrate the laser scanner to ensure its accuracy meets the standards. Second, attach marker points to the structure to facilitate subsequent laser patch scanning. For larger structural components where it is difficult to complete the morphological scanning of the test piece in one go, use lasers of the same frequency to scan each area of ​​the test piece separately, and stitch together the point clouds of each area, removing redundant point clouds after stitching, and saving the point clouds as files for output. Subsequently, denoise the original point cloud. The scanned 3D point cloud data is usually extremely large and discretized, so a hash function raster method is used to denoise the 3D point cloud. To ensure that the scanned point cloud is consistent with the theoretical position, a registration method based on corresponding points is used to register the scanned point cloud and the theoretical position point cloud, obtaining matching pairs between each point in the source point cloud and the target point cloud. Based on the singular value decomposition solution method, the 3D rigid body transformation matrix is ​​obtained using the matching point pairs, thereby realizing the conversion from the source data point cloud to the target point cloud. By comparing the transformed source point cloud and target point cloud, manufacturing geometric deviation information can be determined. A deviation introduction algorithm is used to adjust the finite element model and establish a high-precision numerical model containing measured geometric deviations.

[0031] Step Two: Construct the Static Testing System. Based on the static testing outline, construct the static testing system. The static testing system consists of the tested airborne external attachment, test fixtures, loading tools, and test measuring devices (such as sensors), and assemble these components into an assembly according to the requirements of the testing outline.

[0032] Step 3: Establish a high-precision virtual static test system. The specific steps are as follows:

[0033] 3.1. Based on the ideal positional relationship between the test sample and each part of the test system (including test fixtures, loading fixtures, etc.), establish an ideal assembly model of the virtual test system.

[0034] 3.2. The contact stiffness (i.e., constraint relationship) between the test specimen and the test fixture is accurately equivalently represented using the virtual material method. This involves establishing a thin-layer unit between the model and the test fixture, and assigning virtual material parameters to this thin-layer unit. The contact stiffness between the test specimen and the test fixture is then represented by this thin-layer unit. The parameters of the virtual material include: virtual material thickness h, virtual material area S, virtual material elastic modulus E, and virtual material shear modulus G.

[0035] 3.3 Calculate the virtual material parameters under ideal assembly conditions.

[0036] In the ideal assembly condition, the calculation method of the virtual material parameters between the test product and the test fixture is relatively mature, which can be referred to many existing technologies. For example, according to the technology disclosed in the paper “A Virtual Material Modeling Method Based on Interface Damping Characterization” published by Tian Biao et al. in the 42nd volume of the 7th issue of the mechanical design block of China Network, combined with the surface roughness scanning of the fixture, the thickness parameter, area parameter and elastic modulus parameter of the virtual material in the ideal assembly condition are calculated respectively. The specific steps are as follows:

[0037] 3.3.1, Fractal parameters are parameters used to describe the profile characteristics of rough surfaces to characterize the roughness of the interface, including fractal dimension D and fractal roughness parameter G. Calculating fractal parameters is the cornerstone of calculating the parameters of the virtual material method, therefore, the fractal parameter values of the connecting interface are calculated first. Through the roughness of the test fixture and the two surfaces in contact, combined with electron microscope scanning, the fractal dimension D and the fractal roughness parameter G of the test fixture and the two surfaces in contact can be obtained. This technology is relatively mature and will not be described here.

[0038] 3.3.2, Calculate the thickness parameter of the virtual material.

[0039] Through electron microscope scanning results of the surface of the test product and the surface of the test fixture, according to the thickness parameter calculation formula (Wherein, is the average line height of the rough surface, is the rough surface height deviation, is the thickness of the virtual material), the thickness of the virtual material of the contact surface and the contact surface of the test fixture is calculated respectively, and the total thickness of the virtual material thin layer unit is obtained by summing the two thicknesses.

[0040] 3.3.3, Calculate the area parameter of the virtual material.

[0041] The area of the virtual material is determined according to the effective contact area with the test fixture. According to the assembly relationship with the test fixture, in the ideal assembly condition, the effective contact area with the fixture is S=πdL. Wherein, d is the diameter of the end face, and L is the sleeve depth of the outer hanging object and the test fixture in the ideal assembly.

[0042] 3.3.4, Calculate the elastic modulus and shear modulus of the virtual material according to the calculation formula of the elastic modulus and shear modulus of the virtual material respectively.

[0043] 3.4, Analyze the assembly error of the real assembly body, and introduce the assembly error function. The assembly error of the test assembly body (i.e. the test system) mainly refers to the deviation of the actual relative position between the test product and the test fixture from the ideal assembly position. In the test assembly body, the assembly form of the external object and the fixture is a sleeve joint, and the main assembly error is the assembly gap j with the fixture. For the assembly gap error, the assembly error function can be established: the sleeve joint depth under the ideal assembly condition is L, and the end face is in contact with the end face of the fixture. Due to the influence of the screw pre-tightening force, the manufacturing deviation of the product itself, burr and other factors, there is a gap j between the end face and the fixture in the actual assembly. The sleeve joint depth under the actual assembly condition is L-j, wherein j is the assembly gap length.

[0044] 3.5, Analyze the influence of the assembly error on the virtual material parameters, and establish the calculation method of the virtual material parameters after introducing the assembly error. Through the analysis of the parameters of the virtual material, the parameters affected by the fixture assembly error are the area S of the virtual material, the elastic modulus E of the virtual material and the shear modulus G of the virtual material. After introducing the assembly error, the area of the virtual material is , the elastic modulus of the virtual material is , and the shear modulus of the virtual material is .

[0045] 3.6, Adjust the parameters of the virtual material, and establish a high-precision virtual static test system. Measure the assembly error of the actual assembly body, adjust the parameters of the virtual material according to the established calculation method of the virtual material parameters after introducing the assembly error, and establish a high-precision virtual test system (i.e. a virtual test assembly body) with contact equivalent after introducing the assembly error.

[0046] Note that the adjustment of this step is used to preliminarily determine the range of each virtual material parameter, and the parameters of the virtual material can be adjusted according to the manually measured assembly error. Since the assembly gap j relies on measurement and there are inevitable errors due to many reasons, the virtual material parameters of the virtual test system need to be further accurately valued according to the measured data of the physical test.

[0047] 3.7, Perform assembly error sensitivity analysis. Adjust the assembly gap j in a small range, and calculate the virtual material parameter values (S, E, G, wherein the thickness remains unchanged) under different assembly gaps. Then input different virtual material parameters into the assembly body model and perform simulation test, and the output is the simulation results such as the maximum displacement and the maximum strain corresponding to a specific load.

[0048] The essence of this step is: selecting sampling points of virtual static test within the gap range, correcting the ideal first virtual material parameters of each sampling point according to the ratio between the actual joint depth and the ideal joint depth to obtain the second virtual parameters considering the joint depth gap (wherein the parameters of each sampling point under ideal conditions are consistent, but the correction calculations are independent of each other and differ from each other); then based on each second virtual parameter, a virtual static test is performed to obtain the maximum strain or maximum displacement of the airborne external object under different loads, and then a three-dimensional mapping relationship between the joint depth gap, the load and the maximum strain or the maximum displacement is fitted according to the sampling data.

[0049] In this embodiment, the virtual material parameters are inherent characteristics of the virtual simulation system and do not change with external load changes. However, the relationship between load and strain and displacement satisfies Hooke's law, so in this embodiment, only one of the maximum strain and the maximum displacement needs to be selected in the process of fitting the three-dimensional mapping relationship, and the results of the corresponding final virtual parameters tend to be consistent.

[0050] Step four: Perform virtual test system static test simulation analysis. According to the load conditions in the static test outline, load the product to be tested in the virtual test system for static test, and perform simulation analysis to obtain the full-field virtual mechanical response under test load. In the virtual test system, the load is loaded step by step from 30% design load, and is loaded in turn to 100% according to 10% gradient, and the full-field mechanical response (including displacement, strain cloud map, stress cloud map) is obtained by simulation analysis.

[0051] Step five: Implement physical static test and realize real-time monitoring of the test. According to the requirements of the static test outline, implement the product static test, load the test load step by step according to the 10% gradient, and collect the measured mechanical response data of the product test measurement points in real time through strain gauges and displacement sensors. Fuse the physical static test data and the full-field virtual mechanical response, based on the difference between the measured response data and the virtual test data, use RBF (Radial basis function, Radial basis function) interpolation to construct an additive bridge function, correct the virtual mechanical response, so that it accurately matches the test data at the measurement points and maintains high accuracy in the full-field response, and generate high-fidelity full-field real-time mechanical response of the product under test. Through real-time monitoring of the test site large screen, the full-field mechanical response (including the full-field strain cloud map of the product under test) of the product under test at the current load level under step-by-step loading is monitored in real time, and the high-strain and high-displacement areas of the product under test are detected in real time. Real-time display of static test results and real-time monitoring and early warning of high-risk areas of the product under test are realized.

[0052] In this step, the additive bridge function is a kind of bridge function, and is a key link for realizing the fusion of finite element and strain gauge data. It is assumed that two groups of sample data are known, one group of sample data is the full-field virtual mechanical response of the product under test under the test load, and the other group of sample data is the measured mechanical response data of the product under test at the measurement points under the test load. , ) are large in number, low in cost, but the sample accuracy is relatively low, such as finite element field. Another group of samples ( , ) are small in number, high in cost, but the sample accuracy is high, such as strain gauge data. By using data fusion method, the advantages of the two groups of data samples are connected, and the global response field with the advantages of the two groups of sample data is obtained, such as digital twin field .

[0053] In this embodiment, as an equivalent replacement, the additive bridge function can also be replaced by a multiplicative bridge function or a hybrid bridge function.

[0054] The multiplicative bridge function was first proposed by Haftka based on the multiplicative scaling factor The digital twin field can be represented as: ; wherein, is a surrogate model constructed based on sample points ( , ), is a surrogate model constructed based on variable and the multiplicative scaling factor , can be represented as: .

[0055] When the sample response is close to 0, the multiplicative bridge function tends to fail, and the additive bridge function is developed based on the additive scaling factor The digital twin field can be represented as: ; wherein, is a surrogate model constructed based on variable and the additive scaling factor , can be represented as: .

[0056] Further, Gano proposed a hybrid bridge function to establish a digital twin field , which can be represented as: ; wherein, δ (0≤δ≤1) is a weight coefficient adjusting the contribution of the multiplicative bridge function and the additive bridge function. For different actual engineering problems, the determination of the δ coefficient is crucial to the accuracy of the digital twin field. When the weight coefficient δ=0, the hybrid bridge function method degenerates into the additive bridge function. When the weight coefficient δ=1, the hybrid bridge function method degenerates into the multiplicative bridge function.

[0057] The essence of this step is to perform an actual static test, and to correct the virtual mechanical response by using RBF interpolation according to the difference between the measured mechanical response data of the measuring points and the virtual test data, so as to obtain the maximum strain or maximum displacement of the measured environment under a specific load.

[0058] Step six: calibrate the virtual test system. The specific process is as follows: according to the three-dimensional mapping relationship described above, find the corresponding sleeve joint depth gap of the maximum strain or maximum displacement of the measured environment under a specific load, and then correct the first virtual material parameters of each sampling point according to the ratio between the actual sleeve joint depth corresponding to the search result and the ideal sleeve joint depth to obtain the final virtual parameters of the thin layer element equivalent assembly error for the subsequent virtual static test system; wherein the specific correction formula is the same as step 3.5 above, that is: the thickness remains unchanged, the area is times of the ideal situation, and the elastic modulus and shear modulus are times of the ideal situation.

[0059] Step seven: product manufacturing tolerance analysis. Organize the structure tolerances, and statistically analyze the common uncontrollable manufacturing deviations in the manufacturing process to obtain the structure geometric deviation information. Analyze the influence of each deviation on the static strength of the product one by one.

[0060] Step eight: adjust the size parameters and shape parameters in the virtual test system, adjust the feature size beneficial to the static strength of the structure such as the wall thickness to the lower limit value of the tolerance, and adjust the features not beneficial to the static strength of the structure such as the size of the inspection window to the upper limit value of the tolerance, so that the static strength of the tested product in the virtual test system is the lowest in the product, and the final static strength evaluation virtual test system is formed. Thus, it can be ensured that the airborne external store product verified in the virtual test system of the embodiment is qualified in strength, and even if the product has various deviations in actual manufacturing, the static strength can still be qualified.

[0061] Preferably, after step S6, the following step S7 can be further included.

[0062] Step S7, perform a second actual static test, and determine whether the difference between the measured mechanical response data of the measuring points and the test data obtained by the virtual static test system considering the equivalent assembly error of the thin layer element is within the preset error range. If yes, it is confirmed that the reliability of the virtual static test system meets the requirements; if no, output a notification to the user to return to step S4 after adjustment.

[0063] In this step, the preset error range can be set to 5%.

[0064] Example 2

[0065] Corresponding to the above-mentioned embodiments, the present embodiments disclose an airborne external object static strength evaluation virtual test system, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the method of the above-mentioned embodiments when executing the computer program, which at least comprises the following steps as shown in the accompanying drawings. Figure 1

[0066] Step S1, a topographic scan is performed on the airborne external object test product, and after denoising, source point cloud data is obtained, the source point cloud data is aligned with target point cloud data of an ideal finite element model of the airborne external object through a three-dimensional rigid body transformation matrix, the deviation information of the airborne external object test product in the manufacturing process is determined by comparing the aligned source point cloud data and the target point cloud data, and then the ideal finite element model is trimmed according to the deviation information to obtain an airborne external object finite element model for a virtual static test system.

[0067] Step S2, in the virtual static test system constructed according to the actual static test system, the contact stiffness between the airborne external object finite element model and the test fixture finite element model is equivalent by the virtual material method, and the first virtual material parameters of the thin layer element between the airborne external object finite element model and the test fixture finite element model under ideal assembly condition are calculated.

[0068] Step S3, under the condition that no load is applied to the actual static test system, the gap range caused by the assembly error of the mating depth between the airborne external object and the test fixture is measured.

[0069] Step S4, sampling points for virtual static test are selected within the gap range, the first virtual material parameters of each sampling point are corrected according to the ratio between the actual mating depth and the ideal mating depth to obtain second virtual parameters, virtual static tests are respectively performed based on each of the second virtual parameters to obtain the maximum strain or the maximum displacement of the airborne external object under different loads, and then a three-dimensional mapping relationship between the mating depth gap, the load and the maximum strain or the maximum displacement is fitted according to the sampling data; the actual mating depth is the difference between the ideal mating depth and the assembly gap.

[0070] Step S5, an actual static test is performed, the maximum strain or the maximum displacement of the measured environment under a specific load is obtained by correcting the virtual mechanical response by RBF interpolation according to the difference between the measured mechanical response data of the measuring point and the virtual test data.

[0071] Step S6, the maximum strain or the maximum displacement of the measured environment under a specific load is searched according to the three-dimensional mapping relationship corresponding to the mating depth gap, and then the first virtual material parameters of each sampling point are corrected according to the ratio between the actual mating depth corresponding to the search result and the ideal mating depth to obtain the final virtual parameters of the equivalent assembly error of the thin layer element for subsequent virtual static test system.​

[0072] Similarly, after step S6, further comprising the following step S7.

[0073] Step S7, performing secondary actual static test, according to the difference between the measured mechanical response data of the measuring point and the test data obtained by the virtual static test system considering the equivalent assembly error of the thin layer element, whether in the preset error range, if yes, confirming that the reliability of the virtual static test system meets the requirements, if not, outputting the notification of returning to step S4 after adjustment to the user.

[0074] The specific implementation details of each step are referred to the above-mentioned embodiments, and will not be repeated.

[0075] In summary, the method and system disclosed in the above two embodiments of the present application have at least the following beneficial effects:

[0076] The high-fidelity manufacturing deviation information is recorded in the finite element model of the airborne external object, and on the basis of the existing virtual material method, the sampling points of the virtual static test are selected within the gap range, then according to the ratio between the actual nesting depth and the ideal nesting depth corresponding to the sampling points within the gap range, the first virtual material parameters of each sampling point are corrected to obtain the corresponding second virtual parameters under each gap, and then the three-dimensional mapping relationship between the nesting depth gap, load and maximum strain or maximum displacement is fitted according to the sampling data of the virtual simulation; finally, the actual static test is performed and the three-dimensional mapping relationship is obtained to obtain the nesting depth gap of the measured environment, and then the final virtual parameter of the equivalent assembly error of the thin layer element in the virtual material method is obtained for the subsequent virtual static test system. The logic of each step is echoed and the problem caused by inaccurate assembly error measurement in the virtual static test is reliably solved, so that the static strength evaluation can be realized efficiently, at low cost and reliably instead of the physical static test.

[0077] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A virtual test method for evaluating the static strength of airborne external stores, characterized in that, include: Step S1: After scanning the shape of the airborne external store test product and reducing noise, the source point cloud data is obtained. The source point cloud data is aligned with the target point cloud of the airborne external store physical finite element model through a three-dimensional rigid body transformation matrix. The aligned source point cloud data and target point cloud data are compared to determine the deviation information of the airborne external store test product during the manufacturing process. Then, the airborne external store finite element model is obtained by modifying the physical finite element model according to the deviation information. Step S2: In the virtual static test system constructed based on the actual static test system, the contact stiffness between the finite element model of the airborne external attachment and the finite element model of the test clamp is equivalently represented by the virtual material method. The first virtual material parameters of the thin-layer unit between the finite element model of the airborne external attachment and the finite element model of the test clamp under ideal assembly conditions are obtained. Step S3: Without applying a load to the actual static test system, measure the range of gaps caused by assembly errors in the fitting depth between the airborne external attachment and the test fixture. Step S4: Select sampling points for the virtual static test within the gap range. Correct the first virtual material parameters of each sampling point according to the ratio between the actual fitting depth and the ideal fitting depth to obtain the second virtual parameters. Then, conduct virtual static tests based on each of the second virtual parameters to obtain the maximum strain or maximum displacement of the airborne external attachment under different loads. Finally, fit the sampling data to obtain the three-dimensional mapping relationship between the fitting depth gap, load, and maximum strain or maximum displacement. The actual fitting depth is the difference between the ideal fitting depth and the assembly gap. Step S5: Conduct an actual static test. Based on the difference between the measured mechanical response data at the measurement points and the virtual test data, use RBF interpolation to correct the virtual mechanical response and obtain the maximum strain or maximum displacement of the measured environment under a specific load. Step S6: Based on the three-dimensional mapping relationship, find the sleeve depth gap corresponding to the maximum strain or maximum displacement of the measured environment under a specific load. Then, based on the ratio between the actual sleeve depth and the ideal sleeve depth corresponding to the search result, correct the first virtual material parameters of each sampling point to obtain the final virtual parameters of the equivalent assembly error of the thin-layer unit for use in the subsequent virtual static test system.

2. The virtual test method for static strength assessment of airborne external stores according to claim 1, characterized in that, The process after step S6 also includes: Step S7: Conduct a second actual static test. Check whether the difference between the measured mechanical response data at the measurement point and the test data obtained by the virtual static test system after considering the equivalent assembly error of the thin-layer unit is within the preset error range. If yes, confirm that the reliability of the virtual static test system meets the requirements; if no, output a notification to the user to return to step S4 after adjustment.

3. The virtual test method for static strength assessment of airborne external stores according to claim 1, characterized in that, After considering the equivalent assembly error of thin-layer units, the virtual static test system also includes: The manufacturing tolerances of airborne external stores are analyzed, and the finite element model is adjusted based on the upper or lower limits of the tolerances to minimize static strength.

4. The virtual test method for static strength assessment of airborne external stores according to claim 3, characterized in that, Adjusting the finite element model based on the upper or lower tolerance limit to minimize static strength includes adjusting the wall thickness of the finite element model to the lower tolerance limit and / or adjusting the size of the inspection window in the finite element model to the upper tolerance limit.

5. The virtual test method for static strength assessment of airborne external stores according to any one of claims 1 to 4, characterized in that, The virtual material parameters of the thin-layer unit include: thickness, area, elastic modulus, and shear modulus. The formula for correcting the ideal virtual material parameters of each sampling point based on the ratio between the actual fitting depth and the ideal fitting depth is as follows: The thickness remains constant, and the area is as ideal as possible. times, of which, For ideal socket depth, For gaps caused by assembly errors, the elastic modulus and shear modulus are as they would be under ideal conditions. times.

6. A virtual test system for evaluating the static strength of airborne external stores, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method described in any one of claims 1 to 5.

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