Constraint point load calculation method considering deformation of test piece

Abstract

The invention belongs to the technical field of airplane structure strength test, and particularly relates to a constraint point load calculation method considering test piece deformation, which comprises the following steps: step 1, calculating displacement data of each loading point under different load levels through a virtual test technology; step 2, performing consistency evaluation and correction on the displacement data of each loading point calculated by a virtual test technology according to the displacement data of each loading point obtained by the low-load pre-test test to obtain the displacement data of each loading point under different load levels, which accords with the actual condition; step 3, establishing a test piece loading point loading coordinate and load component calculation model according to the displacement data of each loading point under different load levels, and further calculating to obtain loading coordinates and load components of each loading point under different load levels; and step 4, the loading coordinates and the load components of each loading point under different load levels are substituted into a constraint point load calculation program, and the load of each constraint point is calculated.

Description

Technical Field

[0001] This application belongs to the technical field of aircraft structural strength tests, and specifically relates to a method for calculating constraint point loads considering the deformation of test pieces. Background Art

[0002] In aircraft structural strength tests, a six-degree-of-freedom suspended statically determinate constraint form is usually used to support the test piece. Taking the test piece as the research object, all the active loads applied to the test piece, the weights of the test piece and the loading equipment, and the passive balance loads borne by each constraint point of the test piece together constitute a set of balanced loads to maintain the force and moment balance of the test piece throughout the test process.

[0003] In aircraft structural static / fatigue tests, especially for complex full-aircraft working conditions, the constraint point loads can reflect the real situation of the test, and the constraint point load errors are important data reflecting the overall error size of the test system, which are crucial for data monitoring and decision-making during the test process.

[0004] Currently, for the calculation of the constraint point loads of the test piece, the deformation of the test piece is usually ignored, and the test piece is assumed to be a rigid body. The coordinates and force line directions of each loading point are given theoretically, and this assumption is obviously inconsistent with the actual situation.

[0005] During actual tests, especially when the local deformation of the test piece is large and the force line is short, since the loading equipment is installed at fixed points, when the test piece undergoes obvious deformation, the force line will deviate or deflect greatly from the theoretical direction, resulting in inaccurate loading point load directions and generating additional load components in the additional direction, seriously affecting the accuracy of the calculation of the constraint point loads of the test piece.

[0006] In view of the existence of the above technical defects, this application is proposed. Summary of the Invention

[0007] The purpose of this application is to provide a method for calculating constraint point loads considering the deformation of the test piece, so as to solve the problem that in aircraft structural strength tests, under the suspended statically determinate constraint of the test piece, due to the deformation of the test piece under load, the force lines of each loading point deviate or deflect, resulting in inaccurate calculation of the constraint point loads of the test piece.

[0008] The technical solution of this application is as follows:

[0009] A method for calculating constraint point loads considering the deformation of the test piece includes:

[0010] Step 1: Calculate the displacement data of each loading point at different load levels through virtual test technology;

[0011] Step 2: Use the displacement data of each loading point obtained from the low-load preliminary test to evaluate and correct the displacement data of each loading point calculated by virtual test technology, and obtain the displacement data of each loading point at different load levels that conforms to the actual situation;

[0012] Step 3: Use the displacement data of each loading point at different load levels to establish a calculation model for the loading coordinates and load components of the test piece loading points, and then calculate the loading coordinates and load components of each loading point at different load levels;

[0013] Step 4: Substitute the loading coordinates and load components of each loading point at different load levels into the constraint point load calculation program to calculate each constraint point load.

[0014] According to at least one embodiment of the present application, in the above constraint point load calculation method considering the deformation of the test piece, Step 1 is specifically:

[0015] Use the multi-point distributed load of the loading point and the constraint conditions of the test piece to establish a displacement simulation analysis model for the test piece loading points. Through strength analysis simulation calculation, obtain the structural stress and displacement of the test piece at different load levels, and then extract the displacement data of each loading point at different load levels.

[0016] According to at least one embodiment of the present application, in the above constraint point load calculation method considering the deformation of the test piece, Step 2 is specifically:

[0017] Use the displacement data of each loading point obtained from the low-load preliminary test to evaluate the consistency of the displacement data of each loading point calculated by virtual test technology. When the consistency evaluation does not meet the requirements, analyze the differences between the displacement simulation analysis model of the test piece loading points and the physical model of the preliminary test, and correct the displacement simulation analysis model of the test piece loading points until the consistency evaluation meets the requirements;

[0018] Use the corrected displacement simulation analysis model of the test piece loading points to simulate and calculate the displacement data of each loading point at different load levels.

[0019] According to at least one embodiment of the present application, in Step 2 of the above constraint point load calculation method considering the deformation of the test piece, when using the displacement data of each loading point obtained from the low-load preliminary test to evaluate the consistency of the displacement data of each loading point calculated by virtual test technology, the situation where the consistency evaluation does not meet the requirements means that the displacement data of each loading point calculated by virtual test technology deviates greatly from the displacement data of each loading point obtained from the low-load preliminary test, exceeding the set threshold.

[0020] According to at least one embodiment of the present application, in Step 2 of the above constraint point load calculation method considering the deformation of the test piece, the set threshold is taken as ±1%.

[0021] The present application has at least the following beneficial technical effects:

[0022] A method for calculating the constraint point load considering the deformation of the test piece is provided. The displacement data of each loading point obtained from the low-load preliminary test is used to evaluate and correct the displacement data of each loading point calculated by virtual test technology, so as to obtain the displacement data of each loading point at different load levels that conforms to the actual situation. A calculation model for the loading coordinates and load components of the loading points of the test piece is established, and the loading coordinates and load components of each loading point at different load levels are calculated. Then, they are substituted into the constraint point load calculation program to calculate each constraint point load. Considering the influence of the deviation or deflection of the force lines of each loading point caused by the load deformation of the test piece on the calculation of the constraint point load of the test piece, the constraint point load data that conforms to the actual test situation is obtained. Description of the Drawings

[0023] Figure 1 It is a schematic diagram of the method for calculating the constraint point load considering the deformation of the test piece provided by the embodiment of the present application.

[0024] To better illustrate this embodiment, some contents of the drawings will be omitted, enlarged or reduced, and are only used for exemplary illustration and should not be construed as a limitation to the present application. Detailed Embodiments

[0025] To make the technical solutions and their advantages of the present application clearer, the technical solutions of the present application will be further described clearly and completely in conjunction with the drawings. It can 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 and are not a limitation to 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 drawings, and other related parts can refer to the general design.

[0026] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of the present application should have the ordinary meaning understood by those of ordinary skill in the art to which the present application belongs. The "including" used in the description of the present application means that the concept appearing before this word covers the concepts listed after this word and their equivalents, without excluding other related concepts.

[0027] In addition, the terms indicating directions used in the description of this application are only used to represent relative directions or positional relationships. When the absolute position of the object being described changes, its relative positional relationship may also change accordingly. It should also be noted that unless otherwise clearly specified and limited, terms such as "installation" and "connection" used in the description of this application should be understood in a broad sense. For example, connection can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. Those skilled in the art can understand its specific meaning in this application according to specific circumstances.

[0028] A method for calculating the constraint point load considering the deformation of the test piece, as Figure 1 shown.

[0029] Step 1: Calculate the displacement data of each loading point at different load levels through virtual test technology.

[0030] Adopt the multi-point distributed load of the loading point and the constraint conditions of the test piece to establish a simulation analysis model for the displacement of the loading point of the test piece. Through strength analysis simulation calculation, obtain the structural stress and displacement of the test piece at different load levels, and then extract the displacement data of each loading point at different load levels.

[0031] Step 2: Use the displacement data of each loading point obtained from the low-load pretest to evaluate and correct the displacement data of each loading point calculated through virtual test technology, and obtain the displacement data of each loading point at different load levels that conforms to the actual situation.

[0032] Use the displacement data of each loading point obtained from the low-load pretest to evaluate the consistency of the displacement data of each loading point calculated through virtual test technology. When the consistency evaluation does not meet the requirements, that is, the deviation between the displacement data of each loading point calculated through virtual test technology and the displacement data of each loading point obtained from the low-load pretest is large and exceeds the set threshold, such as 1%, analyze the differences between the simulation analysis model of the displacement of the loading point of the test piece and the physical model of the pretest, and correct the simulation analysis model of the displacement of the loading point of the test piece until the consistency evaluation meets the requirements to ensure that the overall trend of the displacement data after the test piece is loaded is consistent.

[0033] Use the corrected simulation analysis model of the displacement of the loading point of the test piece to simulate and calculate the displacement data of each loading point at different load levels.

[0034] The low-load pretest is a pretest carried out with a relatively low load, using no more than half of the maximum test load, and generally can have considerable safety.

[0035] Step 3: Based on the displacement data of each loading point at different load levels, establish a calculation model for the loading coordinates and load components of the test piece at the loading points, and then calculate the loading coordinates and load components of each loading point at different load levels.

[0036] Step 4: Substitute the loading coordinates and load components of each loading point at different load levels into the constraint point load calculation program to calculate each constraint point load.

[0037] The constraint point load calculation method considering the deformation of the test piece disclosed in the above embodiment uses the displacement data of each loading point obtained from the low-load pre-test to evaluate and correct the displacement data of each loading point calculated by the virtual test technology, and obtains the displacement data of each loading point at different load levels that conforms to the actual situation. Establish a calculation model for the loading coordinates and load components of the test piece at the loading points, calculate the loading coordinates and load components of each loading point at different load levels, substitute them into the constraint point load calculation program, calculate each constraint point load, and consider the influence of the offset or deflection of the force lines at each loading point caused by the deformation of the test piece under load on the calculation of the constraint point load of the test piece, so as to obtain the constraint point load data that conforms to the actual test situation.

[0038] In the aircraft structural strength test, the constraint point load calculation method considering the deformation of the test piece disclosed in the above embodiment can accurately predict the change trend of the constraint point load during the test, obtain the load of each constraint point, and can more truly reflect the actual loading situation and balance state of the test piece, which is beneficial to the judgment of the overall loading error of the test system during the test and the decision-making of the test. It can provide more accurate data basis and support for the data monitoring and decision-making during the test, improve the real-time monitoring and decision-making ability during the test, improve the test efficiency, reduce the test risk, and is beneficial to the analysis of the final test error after the test.

[0039] The constraint point load calculation method considering the deformation of the test piece disclosed in the above embodiment can also be applied to the strength tests of other types of structures, and has high generality.

[0040] So far, the technical solution of the present application has been described in combination with the preferred embodiments shown in the drawings. Those skilled in the art should understand that the protection scope of the present application is obviously not limited to these specific embodiments. Without departing from the principle 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 all fall within the protection scope of the present application.

Claims

1. A method for calculating the constraint point load considering the deformation of the test piece, characterized in that: include: Step 1: Calculate the displacement data of each loading point under different load levels through virtual test technology; Step 2: Using the displacement data of each loading point obtained from the low-load pre-test, the displacement data of each loading point calculated by the virtual test technology is evaluated and corrected for consistency, so as to obtain the displacement data of each loading point at different load levels that are consistent with the actual situation; Step 3: Using the displacement data of each loading point at different load levels, a calculation model for the loading coordinates and load components of the loading points of the test piece is established, and then the loading coordinates and load components of each loading point at different load levels are calculated; Step 4: Bring the loading coordinates and load components of each loading point at different load levels into the constraint point load calculation program to calculate the load of each constraint point.

2. The method for calculating the constraint point load considering the deformation of the test piece according to claim 1, characterized in that: Step 1 is as follows: Using the multi-point distributed loads at the loading points and the constraints of the test piece, a displacement simulation analysis model for the loading points of the test piece is established. The structural stress and displacement of the test piece at different load levels are obtained through strength analysis simulation calculations, and then the displacement data of each loading point at different load levels are extracted.

3. The method for calculating the constraint point load considering the deformation of the test piece according to claim 2, characterized in that: Step 2 is as follows: The displacement data of each loading point obtained from the low-load pre-test is used to conduct consistency assessment on the displacement data of each loading point calculated by the virtual test technology. When the consistency assessment does not meet the requirements, the difference between the displacement simulation analysis model of the loading point of the test piece and the physical model of the pre-test is analyzed, and the displacement simulation analysis model of the loading point of the test piece is corrected until the consistency assessment meets the requirements; Using the modified displacement simulation analysis model of the test piece loading point, the displacement data of each loading point under different load levels are obtained through simulation calculation.

4. The method for calculating the constraint point load considering the deformation of the test piece according to claim 3 is characterized in that: In step 2, the displacement data of each loading point obtained from the low-load pre-test is used to perform a consistency assessment on the displacement data of each loading point calculated by the virtual test technology. Failure to meet the consistency assessment requirement means that the displacement data of each loading point calculated by the virtual test technology deviates greatly from the displacement data of each loading point obtained from the low-load pre-test, exceeding the set threshold.

5. The method for calculating the constraint point load considering the deformation of the test piece according to claim 4, characterized in that: In step 2, the threshold is set to ±1%.

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