A method for determining a node load of a component fatigue test loading

Abstract

The application belongs to the technical field of component fatigue test loading node load determination, and particularly relates to a component fatigue test loading node load determination method, which comprises the following steps: determining a component fatigue test loading node; equivalently taking each loading node as a plurality of loading points, wherein one loading point corresponds to a plurality of loading nodes; determining loading loads corresponding to each loading point under each working condition; constructing a component fatigue test finite element model; constructing a component theoretical state finite element model; taking the loading loads of each loading point corresponding to each working condition as variables, taking a theoretical total load and a total moment as equality constraints, taking a control section error as inequality constraints, limiting the upper and lower limits of the loading loads of each loading point, taking a target response error under the component fatigue test and the theoretical state finite element model as a target variable, obtaining the loading loads of each loading point, and further obtaining the loading loads of each loading node.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of determining loading node load of component fatigue test, and particularly relates to a method for determining loading node load of component fatigue test. BACKGROUND

[0002] There are a large number of structural components in an airplane, and fatigue test on the components is an important means for checking the performance of the components.

[0003] In the fatigue test on the components, the theoretical load borne by the components under each working condition needs to be accurately converted into test loading node load, and a set of loading is applied to simulate the load of all working conditions on the components by determining the loading node distribution ratio, at present, for determining the loading node load of component fatigue test, a large number of repeated iterations and repeated calculations are needed, which is low in efficiency and difficult to ensure the control requirements of the response error (joint load, node displacement, element stress and strain error) of each working condition structure.

[0004] The present application is proposed in view of the above technical defects.

[0005] It should be noted that the disclosure of the above background art is only used to assist in understanding the inventive concept and technical solutions of the present application, and it does not necessarily belong to the prior art of the present patent application. In the absence of explicit evidence that the above content has been disclosed on the filing date of the present application, the above background art should not be used to evaluate the novelty and inventiveness of the present application. SUMMARY

[0006] The purpose of the present application is to provide a method for determining loading node load of component fatigue test, so as to overcome or alleviate at least one aspect of the technical defects known to exist.

[0007] The technical solution of the present application is:

[0008] A method for determining loading node load of component fatigue test, comprising:

[0009] determining the loading node of the component fatigue test;

[0010] equivalent each loading node to a plurality of loading points, wherein one loading point corresponds to a plurality of loading nodes;

[0011] determining the loading load corresponding to each working condition of each loading point;

[0012] constructing a finite element model of component fatigue test;

[0013] constructing a finite element model of component theoretical state;

[0014] The loading load corresponding to each loading point of each working condition is taken as a variable, the theoretical total load and total moment are taken as an equation constraint, the cross section error is taken as an inequality constraint, the upper and lower limits of the loading load of each loading point are limited, the component fatigue test and the target response error under the theoretical state finite element model are taken as target variables, the optimal loading load of each loading point is obtained, and then the loading load of each loading node is obtained.

[0015] According to at least one of the embodiments of the present application, in the component fatigue test loading node load determination method, the component fatigue test loading node is determined as follows:

[0016] The component fatigue test loading node is determined according to the structure form of the component and the theoretical load distribution under the typical working condition.

[0017] According to at least one of the embodiments of the present application, in the component fatigue test loading node load determination method, the equivalent of each loading node to a plurality of loading points is as follows:

[0018] The distribution proportion of each loading node is determined according to the load distribution under the typical working condition, the component is divided into load zones by controlling the cross section error, the loading nodes in each load zone are equivalent to a plurality of loading points, the position of the fatigue test loading point is determined, and the distribution proportion of each loading node in each loading point is obtained.

[0019] According to at least one of the embodiments of the present application, in the component fatigue test loading node load determination method, the target response includes joint support reaction force, node displacement, element strain and stress on the component.

[0020] According to at least one of the embodiments of the present application, in the component fatigue test loading node load determination method, the loading load corresponding to each loading point of each working condition is taken as a variable, the theoretical total load and total moment are taken as an equation constraint, the cross section error is taken as an inequality constraint, the upper and lower limits of the loading load of each loading point are limited, the component fatigue test and the target response error under the theoretical state finite element model are taken as target variables, the loading load of each loading point is obtained, and then the loading load of each loading node is obtained, and the genetic algorithm is used for calculation.

[0021] According to at least one of the embodiments of the present application, in the component fatigue test loading node load determination method, when the target response error under the component fatigue test and the theoretical state finite element model cannot meet the requirements, the target response error weighting matrix is set or adjusted, the target response weight is adjusted, the main target response is ensured to meet the requirements, and the error requirement can be appropriately relaxed for the secondary target response.

[0022] According to at least one embodiment of the present application, in the component fatigue test loading node load determination method described above, when the non-examination area local strain is added to the examination target, the examination target response error under the component fatigue test and the theoretical state finite element model meets the requirements, but the local strain of the non-examination area is too large. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 FIG. 1 is a flowchart of a component fatigue test loading node load determination method provided by an embodiment of the present application.

[0024] In order to better illustrate the present embodiment, some components in the drawings may be omitted, enlarged or reduced, and do not represent the actual size of the product. In addition, the drawings are only used for illustrative description and cannot be understood as a limitation of the present patent. DETAILED DESCRIPTION

[0025] In order to make the technical solutions of the present application and the advantages thereof clearer, the technical solutions of the present application will be further clearly and completely described below with reference to the drawings. It should be understood that the specific embodiments described herein are only part of the embodiments of the present application, and are only used to explain the present application, but not to limit the present application. It should be noted that, for the purpose of description, only parts related to the present application are shown in the drawings, and other related parts can be referred to the general design. In the case of no conflict, the embodiments in the present application and the technical features in the embodiments can be combined to obtain new embodiments.

[0026] In addition, unless otherwise defined, the technical terms or scientific terms used in the present application description should be understood as the general meaning understood by the general technical personnel in the field to which the present application belongs. The words such as "up", "down", "left", "right", "center", "vertical", "horizontal", "inner", "outer" and the like used in the present application description only indicate the relative direction or position relationship, and not the absolute position of the device or element, and the relative position relationship may also change accordingly when the absolute position of the described object changes, therefore, it cannot be understood as a limitation of the present application. The "first", "second", "third" and the like used in the present application description are only for the purpose of description, and are used to distinguish different components, and cannot be understood as indicating or implying relative importance. The "one", "an" or "the" and the like used in the present application description should not be understood as the absolute limitation of the quantity, but should be understood as the existence of at least one. The "include" or "contain" and the like used in the present application description means that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, and do not exclude other elements or objects.

[0027] In addition, it needs to be explained that, unless otherwise explicitly specified and limited, the "installation", "connection", "connection" and similar words used in the description of the present application should be understood broadly, for example, the connection can be fixed connection, or detachable connection, or integrally connected; can be mechanical connection, or electrical connection; can be directly connected, or indirectly connected through intermediate medium, or the internal communication of two elements, and the person skilled in the art can understand the specific meaning of the present application according to the specific situation.

[0028] The following will be combined with the attached Figure 1 The present application is further described in detail.

[0029] A component fatigue test loading node load determination method, comprising:

[0030] Determine the component fatigue test loading node, that is, the setting position of the rubber belt or the tension and pressure pad when the component fatigue test is carried out, which can be matched with the action cylinder to load the component at the position;

[0031] Each loading node is equivalent to a plurality of loading points, wherein one loading point corresponds to a plurality of loading nodes;

[0032] Determine the loading load of each loading point corresponding to each working condition;

[0033] Construct a component fatigue test finite element model;

[0034] Construct a component theoretical state finite element model;

[0035] Take the loading load of each loading point corresponding to each working condition as a variable, take the theoretical total load moment as an equality constraint, take the control section error as an inequality constraint, limit the upper and lower limits of the loading load of each loading point, take the target response error under the component fatigue test and the theoretical state finite element model as a target variable, obtain the loading load of each loading point, and further obtain the loading load of each loading node.

[0036] For the component fatigue test loading node load determination method disclosed in the above embodiment, the person skilled in the art can understand that it is equivalent to a plurality of loading points, and the loading load of each loading point corresponding to each working condition is taken as a variable, the theoretical total load moment is taken as an equality constraint, the control section error is taken as an inequality constraint, the upper and lower limits of the loading load of each loading point are limited, the target response error of the finite element analysis under the component fatigue test and the theoretical state finite element model is taken as a target variable, the loading load of each loading point is obtained, and further the loading load of each loading node is obtained. The calculation converges faster, and the loading load of each loading node can be efficiently obtained. On the basis of ensuring the total load moment and controlling the section error control requirements, the consistency of the structure target response is ensured, and further the reliability of the fatigue test evaluation is ensured.

[0037] In some optional embodiments of the method for determining the loading node of the component fatigue test, the loading node of the component fatigue test is determined in particular as follows:

[0038] The loading node of the component fatigue test is determined according to the theoretical load distribution of the component under typical working conditions.

[0039] In some optional embodiments of the method for determining the loading node of the component fatigue test, each loading node is equivalently converted into a plurality of loading points in particular as follows:

[0040] The loading node of the component fatigue test is determined according to the theoretical load distribution of the component under typical working conditions.

[0041] In some optional embodiments of the method for determining the loading node of the component fatigue test, the target for examination includes the joint reaction force, the node displacement, the element strain and the stress on the component.

[0042] In some optional embodiments of the method for determining the loading node of the component fatigue test, the loading load of each loading point corresponding to each working condition is taken as a variable, the total theoretical load moment is taken as an equation constraint, the cross section error is taken as an inequality constraint, the inequality constraint of the bending moment, shear force and torque error of the cross section is included, the upper and lower limits of the loading load of each loading point are limited, the response error of the target for examination under the component fatigue test and the theoretical state finite element model is taken as a target variable, the loading load of each loading point is obtained, and then the loading load of each loading node is obtained, the genetic algorithm is used for calculation, the finite element model load card is iterated for each generation of the loading load population, the finite element analysis of the component fatigue test finite element model is performed by using the MSC. Nastran software, the target for examination data is extracted from the result file, a new generation of the loading load population is generated through the selection, crossover and mutation of the loading load population, the component fatigue test finite element model is iterated and analyzed, and the target for examination data is extracted, and the loading load of each working condition loading point is gradually converged to the optimal solution.

[0043] In some optional embodiments of the method for determining the loading node of the component fatigue test, when the response error of the target for examination under the component fatigue test and the theoretical state finite element model cannot meet the requirements, the response error weighting matrix of the target for examination is set or adjusted, the response weight of the target for examination is adjusted, the response of the main target for examination is ensured to meet the requirements, and the error requirement can be appropriately relaxed for the secondary target for examination.

[0044] In some optional embodiments, in the above-described method for determining the load at each loading node in a component fatigue test, when the response error of the assessment target meets the requirements under the component fatigue test and the theoretical state finite element model, but there is excessive local strain in the non-assessment area, the local strain in the non-assessment area is added to the assessment target. Under this assessment target, the loading load corresponding to each loading point under each working condition is used as a variable, and the theoretical total load moment is used for equality constraints, while the control profile error is used for inequality constraints to limit the upper and lower limits of the loading load at each loading point. The response error of the assessment target under the component fatigue test and the theoretical state finite element model is used as the target variable to obtain the loading load at each loading point, and then obtain the loading load at each loading node. This can avoid the situation of excessive local strain during component fatigue testing and ensure the safety of the test.

[0045] The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0046] The technical solution of this 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 this application is obviously not limited to these specific embodiments. Without departing from the principles of this 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 scope of protection of this application.

Claims

1. A method for determining the loading node load in a component fatigue test, characterized in that, include: Determine the loading points for component fatigue testing; Each loading node is equivalent to multiple loading points, where one loading point corresponds to multiple loading nodes; Determine the load at each loading point corresponding to each working condition; Construct a finite element model for component fatigue testing; Construct a finite element model of the theoretical state of the component; Using the loading load corresponding to each loading point under each working condition as variables, the theoretical total load and total moment are used for equality constraints, and the control profile error is used for inequality constraints to limit the upper and lower limits of the loading load at each loading point. The target response error under component fatigue test and theoretical state finite element model is used as the target variable to obtain the loading load at each loading point, and then obtain the loading load at each loading node. The process of equating each loading node with multiple loading points specifically involves: The load distribution ratio of the loading nodes is determined based on typical working conditions. The load section is divided into load zones for the component. The loading nodes in each load zone are equivalent to multiple loading points. The location of the loading point for fatigue test is determined, and the distribution ratio of each loading node in each loading point is obtained. The assessment targets include the reaction force of the joint support on the component, the nodal displacement, the element strain and its stress.

2. The method for determining the loading node load in component fatigue testing according to claim 1, characterized in that, The specific details of determining the fatigue test loading node for the component are as follows: Based on the component's structural form and the theoretical load distribution under typical working conditions, the loading nodes for the component fatigue test are determined.

3. The method for determining the loading node load in component fatigue testing according to claim 1, characterized in that, The loading load at each loading point corresponding to each working condition is used as a variable. Equality constraints are applied using the theoretical total load moment, and inequality constraints are applied using the control profile error. The upper and lower limits of the loading load at each loading point are limited. The target response error under component fatigue test and theoretical state finite element model is used as the target variable to obtain the loading load at each loading point, and then the loading load at each loading node is obtained. The genetic algorithm is used for calculation.

4. The method for determining the loading node load in component fatigue testing according to claim 1, characterized in that, When the response error of the assessment target cannot meet the requirements under component fatigue test and theoretical state finite element model, set or adjust the weighting matrix of the assessment target response error, adjust the weight of the assessment target response, and ensure that the response of the main assessment target meets the requirements. For secondary assessment targets, the error requirements can be appropriately relaxed.

5. The method for determining the loading node load in component fatigue testing according to claim 1, characterized in that, If the response error of the assessment target meets the requirements under component fatigue test and theoretical state finite element model, but there is excessive local strain in non-assessment area, the local strain in non-assessment area will be added to the assessment target.

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