Aircraft rivet load prediction method, device, equipment and medium

Abstract

The invention discloses an aircraft rivet load prediction method and device, equipment and a medium, and the method comprises the steps: generating a finite element model based on a to-be-riveted part, obtaining a first coordinate of a first riveting hole corresponding to an initial state, adding a connection unit to a second riveting hole, enabling a first connection part to meet a first preset state, and enabling the first connection part to meet a second preset state; the node force of the connecting unit in the corresponding second riveting hole is obtained, under the condition that the node force meets the preset condition, the second coordinate of the first riveting hole in the first state is obtained, and then the displacement load corresponding to the first riveting hole is calculated through the first coordinate and the second coordinate; the corresponding displacement load is added to each first riveting hole, the bearing reaction force corresponding to the first riveting holes and the bearing reaction force corresponding to the second riveting holes are obtained, and therefore the riveting load of the rivet corresponding to the to-be-riveted part is obtained. According to the method, the technical problem that errors are large when the load of the rivet for assembling the interference part is predicted through experience judgment and an equivalent test method can be solved.

Description

Technical Field

[0001] The present application relates to the field of aircraft assembly, and in particular to an aircraft rivet load prediction method, device, equipment and medium. Background Art

[0002] An aircraft is an assembly composed of a large number of parts that are connected by riveting, welding and other connection methods. Due to the large number of parts on an aircraft and the fact that most of the parts have complex shapes and weak rigidity, manufacturing errors are easily generated during the production process, causing its appearance to often deviate from the theoretical shape. Ultimately, interference between adjacent parts will occur during the assembly process, which is also called assembly interference.

[0003] During the assembly of aircraft parts, forced assembly is often used to assemble parts with assembly interference. Forced assembly will inevitably introduce additional loads. If the additional loads introduced are too large, it will seriously affect the overall quality of the aircraft. In order to accurately control the additional loads introduced by forced assembly, identify the risks of forced assembly, and ensure assembly quality, it is necessary to determine the loads after forced assembly for different interfering parts. When there is interference between parts and adjacent parts due to processing errors during aircraft assembly, the prior art predicts the additional loads of rivets after forced assembly of interfering parts through empirical judgment and equivalent test methods.

[0004] However, there is a defect of large error in predicting the load of rivets of interference parts through empirical judgment and equivalent test methods. Summary of the invention

[0005] The main purpose of the present application is to provide a method, device, equipment and medium for predicting aircraft rivet loads, aiming to solve the technical problem that there is a large error in predicting the load of rivets of interference parts through empirical judgment and equivalent test methods.

[0006] To achieve the above object, the present application provides a method for predicting aircraft rivet loads, the method comprising the following steps:

[0007] Generate a finite element model according to the structural features of the part to be riveted; wherein the part to be riveted includes a first connecting portion and a second connecting portion, the first connecting portion is provided with at least one first rivet hole for connecting with a first assembly part, and the second connecting portion is provided with at least one second rivet hole for connecting with a second assembly part;

[0008] Acquire the first coordinates of the first rivet holes, and add a connection unit to each of the second rivet holes;

[0009] When the first connection portion is in a first preset state and the node force of the connection unit meets a preset condition, acquiring a second coordinate corresponding to the first riveting hole;

[0010] Acquire a displacement load according to the first coordinate and the second coordinate, and apply a corresponding displacement load to each of the first rivet holes;

[0011] The riveting load is acquired and outputted, where the riveting load is the support reaction force at each of the first riveting hole and the second riveting hole.

[0012] Optionally, the first preset state is a state in which the first connection portion is in contact with the first assembly part. Before the first connection portion is in the first preset state, the method further includes:

[0013] The first connecting part is placed in a second preset state by applying an external force load to the first connecting part; wherein the external force load is configured to eliminate assembly interference of the first connecting part; when the first connecting part is in the second preset state, the first connecting part is separated from the first assembly part;

[0014] Removing the external force load places the first connecting portion in a first preset state.

[0015] Optionally, before the node force of the connection unit meets a preset condition, the method further includes:

[0016] Obtaining the allowable stress of the connection unit; wherein the allowable stress includes allowable tensile stress and allowable shear stress;

[0017] Obtaining the node force of the connection unit, and converting the node force into the actual stress of the connection unit; wherein the actual stress is obtained by synthesizing the node force;

[0018] The value of the actual stress is compared with the value of the allowable stress.

[0019] Optionally, the preset condition is that the value of the actual stress is less than or equal to the value of the allowable stress;

[0020] The allowable stress includes the allowable tensile stress and the allowable shear stress corresponding to the rivet being riveted at the second rivet hole.

[0021] Optionally, after the step of comparing the value of the actual stress with the value of the allowable stress, the method further comprises:

[0022] When the value of the actual stress is greater than the value of the allowable stress, removing the connection unit corresponding to the actual stress;

[0023] Thereafter, when the first connection portion is in a first preset state and the node force of the connection unit meets a preset condition, the second coordinate corresponding to the first riveting hole is reacquired.

[0024] Optionally, before the step of acquiring the first coordinates of the first rivet hole, the method further includes:

[0025] Setting a reference point at the center of each of the first riveting holes;

[0026] The first coordinate and the second coordinate are both obtained based on the coordinate of the reference point.

[0027] Optionally, the step of adding a connection unit to each of the second riveting holes includes:

[0028] Acquire an actual connection state corresponding to the second connection portion; wherein the actual connection state includes a position of the second rivet hole for connecting the rivet;

[0029] A connecting unit is added to the second riveting hole at a corresponding position.

[0030] In addition, to achieve the above-mentioned purpose, the present application also provides an aircraft rivet load prediction device, the device comprising:

[0031] The model generation module is configured to generate a finite element model according to the structural features of the part to be riveted; wherein the part to be riveted includes a first connecting portion and a second connecting portion, the first connecting portion is provided with at least one first rivet hole for connecting with a first assembly part, and the second connecting portion is provided with at least one second rivet hole for connecting with a second assembly part;

[0032] A model initialization module is configured to obtain a first coordinate of the first rivet hole and add a connection unit to each of the second rivet holes;

[0033] A coordinate acquisition module, configured to acquire a second coordinate corresponding to the first riveting hole when the first connection portion is in a first preset state and the node force of the connection unit meets a preset condition;

[0034] an interference adjustment module, configured to obtain a displacement load according to the first coordinate and the second coordinate, and apply a corresponding displacement load to each of the first riveting holes;

[0035] The load output module is configured to obtain and output a riveting load, where the riveting load is a support reaction force at each of the first riveting holes and the second riveting holes.

[0036] In addition, to achieve the above-mentioned purpose, the present application also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0037] Generate a finite element model according to the structural features of the part to be riveted; wherein the part to be riveted includes a first connecting portion and a second connecting portion, the first connecting portion is provided with at least one first rivet hole for connecting with a first assembly part, and the second connecting portion is provided with at least one second rivet hole for connecting with a second assembly part;

[0038] Acquire the first coordinates of the first rivet holes, and add a connection unit to each of the second rivet holes;

[0039] When the first connection portion is in a first preset state and the node force of the connection unit meets a preset condition, acquiring a second coordinate corresponding to the first riveting hole;

[0040] Acquire a displacement load according to the first coordinate and the second coordinate, and apply a corresponding displacement load to each of the first rivet holes;

[0041] The riveting load is acquired and outputted, where the riveting load is the support reaction force at each of the first riveting hole and the second riveting hole.

[0042] In addition, to achieve the above-mentioned purpose, the present application also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

[0043] Generate a finite element model according to the structural features of the part to be riveted; wherein the part to be riveted includes a first connecting portion and a second connecting portion, the first connecting portion is provided with at least one first rivet hole for connecting with a first assembly part, and the second connecting portion is provided with at least one second rivet hole for connecting with a second assembly part;

[0044] Acquire the first coordinates of the first rivet holes, and add a connection unit to each of the second rivet holes;

[0045] When the first connection portion is in a first preset state and the node force of the connection unit meets a preset condition, acquiring a second coordinate corresponding to the first riveting hole;

[0046] Acquire a displacement load according to the first coordinate and the second coordinate, and apply a corresponding displacement load to each of the first rivet holes;

[0047] The riveting load is acquired and outputted, where the riveting load is the support reaction force at each of the first riveting hole and the second riveting hole.

[0048] The beneficial effects that can be achieved by this application.

[0049] A method, device, equipment and medium for predicting aircraft rivet loads proposed in the embodiments of the present application can achieve the purpose of simplifying the predicted loads of complex aircraft components and interference parts by generating a finite element model based on the parts to be riveted, by obtaining the first coordinate of the first riveting hole corresponding to the initial state, adding a connecting unit to the second riveting hole at the same time, and making the first connecting part satisfy the first preset state, obtaining and judging whether the node force of the connecting unit in the corresponding second riveting hole satisfies the preset conditions, and obtaining the second coordinate of the first riveting hole in the first state when the node force satisfies the preset conditions, and then calculating the displacement load of the corresponding first riveting hole through the first coordinate and the second coordinate; the first preset state corresponds to the state in which the parts to be riveted reach contact with the first assembly part and the second assembly part in actual production, which is equivalent to the state in which the applied external force is cancelled after the parts to be riveted contact with the first assembly part and the second assembly part. By applying a displacement load, the first connecting portion reaches a first preset state, and by adding a corresponding displacement load to each first rivet hole and obtaining the corresponding support reaction force of the first rivet hole and the second rivet hole, the riveting load of the rivet corresponding to the part to be riveted is obtained, thereby improving the accuracy of obtaining the predicted load at the rivet, and also being able to evaluate the quality of the product after assembly, thereby achieving the purpose of ensuring reliable assembly of parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 A schematic diagram of the flow chart of the aircraft rivet load prediction method provided in this application;

[0051] Figure 2 A schematic diagram of the overall flow of the aircraft rivet load prediction method provided in this application;

[0052] Figure 3 for Figure 2 A detailed flow chart of the step of adding a connection unit to each of the second riveting holes;

[0053] Figure 4 for Figure 2 A detailed flow chart of the step of placing the first connecting portion in a first preset state;

[0054] Figure 5 for Figure 2 A detailed flow chart of the steps in which the node force of the connecting unit meets the preset conditions;

[0055] Figure 6 A schematic diagram of the functional modules of the aircraft rivet load prediction device provided in this application.

[0056] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0057] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0058] The main solution of the embodiment of the present application is: by generating a finite element model based on the parts to be riveted, the purpose of simplifying the predicted load of the parts interfering with the complex parts of the aircraft can be achieved; by obtaining the first coordinate of the first riveting hole corresponding to the initial state, adding a connecting unit to the second riveting hole, and making the first connecting part meet the first preset state, obtaining and judging whether the node force of the connecting unit in the corresponding second riveting hole meets the preset condition; when the node force meets the preset condition, obtaining the second coordinate of the first riveting hole in the first state, and then calculating the displacement load of the corresponding first riveting hole through the first coordinate and the second coordinate; by applying the displacement load, the first connecting part reaches the first preset state, by adding the corresponding displacement load to each first riveting hole, and obtaining the corresponding support reaction force of the first riveting hole and the second riveting hole, the riveting load of the rivet corresponding to the part to be riveted is obtained, thereby improving the accuracy of obtaining the predicted load at the rivet, and at the same time being able to evaluate the quality of the product after assembly, thereby achieving the purpose of ensuring reliable assembly of parts.

[0059] In the prior art, the prediction of the load of assembly parts through empirical judgment requires high process experience, and this method is usually applicable to parts with simple shapes such as thin plates. However, the number of parts on an aircraft is extremely large and the structural shapes are very complex. Relying on empirical judgment will result in large errors and is difficult to apply in the assembly process of aircraft parts. The method of using equivalent tests to predict the load of assembly parts is also more effective for parts with simple shapes. However, in the actual production process, the shapes of aircraft parts are mostly spatial curved surfaces with irregular shapes and complex connection relationships. The equivalent test method will take a lot of time. At the same time, if equivalent tests are used for different assembly part structures on the aircraft, it will lead to increased costs.

[0060] The present application provides a solution, which can simplify the predicted load of the interference parts of the aircraft complex parts by generating a finite element model based on the parts to be riveted, obtain the first coordinate of the first riveting hole corresponding to the initial state, add a connecting unit to the second riveting hole, and make the first connecting part meet the first preset state, obtain and judge whether the node force of the connecting unit in the corresponding second riveting hole meets the preset condition, and when the node force meets the preset condition, obtain the second coordinate of the first riveting hole in the first state, and then calculate the displacement load of the corresponding first riveting hole by the first coordinate and the second coordinate; apply the displacement load to make the first connecting part reach the first preset state, add the corresponding displacement load to each first riveting hole, and obtain the corresponding support reaction force of the first riveting hole and the second riveting hole, so as to obtain the riveting load of the rivet corresponding to the part to be riveted, thereby improving the accuracy of obtaining the predicted load at the rivet, and at the same time can evaluate the quality of the product after assembly, so as to achieve the purpose of ensuring the reliable assembly of parts.

[0061] Reference Figure 1 and Figure 2 , an embodiment of the present application provides a method for predicting aircraft rivet loads, the method comprising the following steps: step S10, step S20, step S30, step S40 and step S50.

[0062] Step S10, generating a finite element model according to the structural features of the part to be riveted; wherein the part to be riveted includes a first connecting portion and a second connecting portion, the first connecting portion is provided with at least one first rivet hole for connecting to a first assembly part, and the second connecting portion is provided with at least one second rivet hole for connecting to a second assembly part.

[0063] In this embodiment, the finite element model is obtained by modeling the parts to be riveted in the assembly interference state. The finite element model can be used to predict the force applied to its surface and predict the process of the structural offset in the model and the influence of the stress inside it. Due to the geometric error of the parts to be riveted, interference occurs with the first assembly part or the second assembly part during the assembly process. In this case, the structural characteristics of the parts to be riveted need to be obtained. By establishing a finite element model similar to the structure of the parts to be riveted, it is convenient to correspond the deformation degree and the applied force of the finite element model, so as to output the stress load corresponding to the parts to be riveted.

[0064] The characteristic dimensions of the riveted parts with geometric errors are length l, width w and height h. The local geometric model is intercepted from the combined overall geometric model with the position of the riveted parts as the center. The interfaces formed by the interception are S1, S2...Sm; and the characteristic dimensions of the local geometric model obtained by interception are length L, width W, and height H. The characteristic dimensions of the local geometric model and the characteristic dimensions of part 1 meet the following conditions: L≥2.5l, W≥2.5w, H≥2.5h.

[0065] Exemplarily, the characteristic dimensions of the parts to be riveted in the embodiment of the present application are as follows: l=25mm, w=16mm, h=25mm; it can be seen that the boundary representation of the size of the local geometric model obtained according to the corresponding relationship is as follows: L=70mm, W=50mm, H=70mm.

[0066] Then, a finite element model is established according to the assembly interference state of the parts to be riveted, so that the contact surface between the parts to be riveted and the second assembly part is fitted. At the same time, the parts to be riveted overlap with the first assembly part, and the overlapping part is the interference position of the parts to be riveted. The reference interference amount between the parts to be riveted and the first assembly part is obtained. The reference interference amount is expressed as δ0. The reference interference amount can be obtained by comparing the established geometric model or by measuring the three-dimensional digital model under the interference state. In this embodiment, the reference interference amount δ0=1mm is obtained by comparing the established geometric model.

[0067] Step S20, obtaining the first coordinates of the first rivet holes, and adding a connection unit to each of the second rivet holes.

[0068] The first coordinate is the coordinate of the first rivet hole in the assembly interference state. The value corresponding to the first coordinate is obtained by measuring the position of each first rivet hole in the finite element model. At the same time, a connecting unit is added to the second connecting hole, and a contact property is set between the second connecting part and the second assembly part through the connecting unit. The first connecting part and the first assembly part are in a non-contact state.

[0069] Exemplarily, the connection unit corresponds to a rivet passing through the second riveting hole, the connection unit is set as a one-dimensional unit, the connection unit is used to ensure that the second connection part and the second assembly part remain in a fitted state, and the size of the connection unit is the same as the size of the rivet, the radius of the connection unit is represented by r, and the length is represented by L ’ In this embodiment, the connection unit can be represented by a beam unit, r = 1.5 mm, L ’ =1.5mm.

[0070] Step S30: when the first connection portion is in a first preset state and the node force of the connection unit meets a preset condition, obtaining a second coordinate corresponding to the first riveting hole.

[0071] The first preset state is a state in which the first connection portion of the corresponding finite element model reaches contact with the first assembly part. The stress load borne by the corresponding finite element model when it moves to the first preset state can be obtained by finite element analysis. At the same time, after the node force connected at the second rivet hole is judged by preset conditions, the second coordinate of the first rivet hole after the corresponding assembly is completed is obtained, which can facilitate the prediction of the load borne by the rivet in the first rivet hole and the second rivet hole to a certain extent, so as to improve the accuracy of predicting the load borne by the rivet used to connect the parts to be riveted.

[0072] Step S40: obtaining a displacement load according to the first coordinate and the second coordinate, and applying a corresponding displacement load to each of the first rivet holes.

[0073] The displacement load represents the external force that needs to be applied to eliminate the assembly interference state of the first connection part. At the same time, since the first connection part is connected to the first assembly part through the first rivet hole, the purpose of eliminating the assembly interference state of the first connection part can be achieved by applying the displacement load at the first rivet hole.

[0074] The first coordinate corresponds to the first connection part in the interference state, and the second coordinate corresponds to the first connection part in the normal assembly state. The displacement load corresponding to the first connection part can be obtained through the first coordinate and the second coordinate. By applying the displacement load to each first rivet hole, the first connection part is deformed to the normal installation state, so as to facilitate the subsequent measurement of the support reaction force at the first rivet hole and the second rivet hole, thereby improving the probability of obtaining the accuracy of the predicted load corresponding to the rivet on the part to be riveted after actual assembly.

[0075] Step S50, acquiring and outputting a riveting load, where the riveting load is a support reaction force at each of the first riveting holes and the second riveting holes.

[0076] By obtaining the support reaction force of the first rivet hole and the second rivet hole corresponding to the normal assembly state, the support reaction force corresponds to the parts to be riveted after normal assembly. At the same time, the support reaction force at the first rivet hole and the second rivet hole is equivalent to the load borne by the rivet after the parts to be riveted are normally assembled. This can improve the accuracy of predicting the rivet load connected to the parts to be riveted.

[0077] By generating a finite element model based on the parts to be riveted, the purpose of simplifying the predicted load of the interference parts of the complex aircraft parts can be achieved. By obtaining the first coordinate of the first riveting hole corresponding to the initial state, adding a connecting unit to the second riveting hole, and making the first connecting part meet the first preset state, it is obtained and judged whether the node force of the connecting unit in the corresponding second riveting hole meets the preset condition. When the node force meets the preset condition, the second coordinate of the first riveting hole in the first state is obtained, and then the displacement load of the corresponding first riveting hole is calculated by the first coordinate and the second coordinate; the first connecting part reaches the first preset state by applying the displacement load, and the corresponding displacement load is added to each first riveting hole, and the corresponding support reaction force of the first riveting hole and the second riveting hole is obtained, so as to obtain the riveting load of the rivet corresponding to the part to be riveted, thereby improving the accuracy of obtaining the predicted load at the rivet, and at the same time, it is also possible to evaluate the quality of the product after assembly, so as to achieve the purpose of ensuring reliable assembly of parts.

[0078] In some embodiments, before the step of obtaining the first coordinates of the first rivet holes, the method further includes: setting a reference point at the center of each of the first rivet holes; and both the first coordinates and the second coordinates are obtained based on the coordinates of the reference point.

[0079] A reference point is established by using coupling constraints between the center of the first riveting hole and the hole wall. The reference point is used to obtain the displacement degree of the first connecting part after eliminating assembly interference, so as to facilitate the subsequent acquisition of the load borne by the rivet after the corresponding riveted parts are assembled based on the displacement degree of the first connecting part.

[0080] In some embodiments, reference Figure 3 The step of adding a connection unit to each of the second riveting holes includes: step S201 and step S202.

[0081] Step S201, obtaining an actual connection state corresponding to the second connection portion; wherein the actual connection state includes a position of the second rivet hole for connecting the rivet.

[0082] Since there is no one-to-one correspondence between the second rivet hole and the rivet connected to the second connecting part during the actual assembly process, the accuracy of predicting the assembly of the rivet at the second rivet hole and the second assembly part can be greatly improved by obtaining the actual rivet corresponding position of the second connecting part during the assembly process.

[0083] Step S202: adding a connection unit to the second riveting hole at a corresponding position.

[0084] The connection unit is used to simulate the state of the rivet connecting the second connection part during the actual assembly process, so as to reduce the probability of errors in the subsequent prediction process of the parts to be riveted, and improve the accuracy of predicting the load-bearing capacity of the rivet connecting the parts to be riveted.

[0085] In some embodiments, reference Figure 4 The first preset state is a state in which the first connection portion is in contact with the first assembly part. Before the first connection portion is in the first preset state, the method further includes: step S301 and step S302.

[0086] Step S301, applying an external force load to the first connection part to put the first connection part in a second preset state, wherein the external force load is configured to eliminate assembly interference of the first connection part; when the first connection part is in the second preset state, the first connection part is separated from the first assembly part.

[0087] In the second preset state, the first connection part and the first assembly part are separated and do not interfere with each other, while in the first preset state, the first connection part contacts and does not interfere with the first assembly part due to its own elasticity, thereby facilitating subsequent analysis of the load of the first connection part.

[0088] Step S302, removing the external force load to place the first connection portion in a first preset state.

[0089] The assembly interference state between the first connection part and the first assembly part is eliminated by applying an external force load, the external force load applied in this process is expressed as δ, and the relationship between the external force load and the reference interference amount is expressed as δ0<δ≤1.2δ0. In this embodiment, the external force load δ=1.2mm, and the direction of the external force load is away from the assembly interference area of ​​the first connection part, and the external force load is perpendicular to the surface of the interference area of ​​the first connection part.

[0090] Applying an external force load can separate the assembly interference area between the first connection part and the first assembly part, facilitate the contact between the first connection part and the first assembly part without interference, and further realize the simulation of the assembly state of the first connection part and the first assembly part, which is convenient for the subsequent analysis of the load borne on the surface of the first connection part.

[0091] In the actual production process, after the first connection part is connected to the first assembly part under the action of external force, the first connection part can be placed in a natural state by removing the external force on the surface of the first connection part, which further facilitates the subsequent mechanical analysis of the finite element model, thereby reducing the impact of external force loads on the accuracy of load analysis on the surface of the finite element model.

[0092] In some embodiments, reference Figure 5Before executing the step of ensuring that the node force of the connection unit meets a preset condition, the method provided in the present application includes: step S303, step S304 and step S305.

[0093] Step S303, obtaining the allowable stress of the connection unit; wherein the allowable stress includes the allowable tensile stress and the allowable shear stress.

[0094] The allowable stress is the allowable tensile stress and the allowable shear stress of the rivet corresponding to the connection unit after riveting, and the allowable stress can be calculated by the process specification, the allowable tensile stress is expressed as [σ], and the allowable shear stress is expressed as [τ]. For example, [σ] = 80MPa, [τ] = 50MPa.

[0095] When the first connection part is in the first preset state, the load borne by the connection unit is verified by the obtained allowable stress, thereby achieving the accuracy of simulating the reliable connection of the second connection part through the connection unit, which facilitates the subsequent analysis of the load borne by the first connection part.

[0096] Step S304, obtaining the node force of the connection unit, and converting the node force into the actual stress of the connection unit; wherein the actual stress is obtained by synthesizing the node force.

[0097] The node force of the connection unit is obtained by measuring the finite element model, and the component forces of the node force of the connection unit are expressed as Fix, Fiy and Fiz, where i = 1, 2...k. i represents the number of connection units between the part to be riveted and the first assembly part; the directions of Fix, Fiy and Fiz are perpendicular to each other, and any direction of Fix, Fiy and Fiz is parallel to the axial direction of the connection unit. The actual stress includes the actual tensile stress and the actual shear stress.

[0098] The relationship between the actual stress and node force corresponding to each connection unit is expressed as:

[0099]

[0100] Where i represents the serial number of the connection unit; σ i It is represented by the actual tensile stress borne by the connection unit at the i-th second rivet hole; σ i It is represented by the actual shear stress borne by the connection unit at the second rivet hole of the i-th node; subscript 1 represents the direction in x, y, z that is the same as the axial direction of the 1D unit, and subscripts 2 and 3 represent the other two directions of the component of the node force; r represents the radius of the connection unit; L ’ Indicates the length of the connection unit.

[0101] Step S305, comparing the value of the actual stress with the value of the allowable stress.

[0102] By comparing the actual stress value with the allowable stress value, it is possible to determine whether the connection unit provided at the second riveting hole has failed by using the allowable stress. When all the connection units are valid, it is convenient to obtain the displacement load of the first connection part, and to predict the load borne by the rivet used to connect the parts to be riveted.

[0103] In some embodiments, the preset condition is that the value of the actual stress is less than or equal to the value of the allowable stress; wherein the allowable stress includes the allowable tensile stress and the allowable shear stress corresponding to the rivet after being riveted at the second rivet hole.

[0104] After the step of comparing the value of the actual stress with the value of the allowable stress, the method provided in the present application further includes: when the value of the actual stress is greater than the value of the allowable stress, removing the connection unit corresponding to the actual stress; when the first connection part is in a first preset state and the node force of the connection unit meets a preset condition, obtaining a second coordinate corresponding to the first rivet hole.

[0105] By using the allowable stress to verify the load borne by the connection unit, when the actual stress borne by the connection unit is greater than the allowable stress, it indicates that the corresponding connection unit has failed. Therefore, the connection unit at the corresponding position where the actual stress is greater than the allowable stress is removed, and when the first connection part is restored to the first preset state and the node force of the connection unit meets the preset conditions, the second coordinate corresponding to the first rivet hole is obtained.

[0106] In some embodiments, when the first connection portion is in the first preset state, the node force of the connection unit obtained by measurement is expressed as Table 1, which is as follows:

[0107] Table 1

[0108]

[0109] The node force of the connection unit obtained by the corresponding expression of the actual stress and the node force corresponding to each connection unit is expressed as Table 2. Table 2 is as follows:

[0110] Table 2

[0111] Second rivet hole number 1 2 3 4 <![CDATA[σ i (MPa)]]> 96 15 14 1 <![CDATA[τ i (MPa)]]> 37 7 34 21

[0112] When the actual stress of the connection unit is checked by the allowable stress, since [σ] = 80 MPa and [τ] = 50 MPa, the actual tensile stress of the connection unit corresponding to the second rivet hole numbered 1 is greater than the allowable tensile stress. By removing the connection unit at the second rivet hole numbered 1 and when the first connection part is in the first preset state again, the node force of the connection unit is re-obtained and expressed as Table 3. Table 3 is as follows:

[0113] Table 3

[0114]

[0115] The node force of the connection unit obtained by the corresponding expression of the relationship between the actual stress and the node force corresponding to each connection unit is expressed as Table 4. Table 4 is as follows:

[0116] Table 4

[0117]

[0118]

[0119] In summary, after removing the connection unit at the second rivet hole numbered 1, the remaining connection units set at the second rivet holes all meet the preset conditions, so the second coordinate of the first rivet hole is obtained, and the second coordinate is expressed as U0, and the expression is as follows:

[0120]

[0121] Wherein, p represents the number of first rivet holes between the part to be riveted and the first assembly part.

[0122] At the same time, the first coordinate is represented as U1, and the expression is as follows:

[0123]

[0124] Wherein, p represents the number of first rivet holes between the part to be riveted and the first assembly part.

[0125] The displacement load is obtained through the first coordinate and the second coordinate. The displacement load is expressed as U and the expression is as follows:

[0126]

[0127] Wherein, p represents the number of first rivet holes between the part to be riveted and the first assembly part.

[0128] In some embodiments, the number of first rivet holes obtained is 6, and the second coordinates U0 corresponding to all first rivet holes obtained are expressed as:

[0129]

[0130] The first coordinate U1 is expressed as:

[0131]

[0132] The corresponding displacement load is therefore:

[0133]

[0134] Since the connecting unit at the second rivet hole numbered 1 is removed, a load of (0,0,0) is applied to the corresponding second rivet hole, so as to obtain the nodal force borne by the first rivet hole and the second rivet hole on the part to be riveted, thereby improving the accuracy of predicting the load at the rivet after the interference state of the part to be riveted is eliminated.

[0135] In some embodiments, the support reaction forces at the first rivet hole and the second rivet hole obtained by applying a displacement load to each first rivet hole are shown in Table 5. Table 5 is as follows:

[0136] Table 5

[0137]

[0138] The obtained support reaction force is the load borne by the corresponding rivets of the first riveting hole and the second riveting hole after the interference state is eliminated.

[0139] In addition, to achieve the above purpose, refer to Figure 6 The present application also provides an aircraft rivet load prediction device, which includes: a model generation module 610, a model initialization module 620, a coordinate acquisition module 630, an interference adjustment module 640 and a load output module 650.

[0140] The model generation module 610 is configured to generate a finite element model according to the structural features of the part to be riveted; wherein the part to be riveted includes a first connecting portion and a second connecting portion, the first connecting portion is provided with at least one first rivet hole for connecting to a first assembly part, and the second connecting portion is provided with at least one second rivet hole for connecting to a second assembly part.

[0141] The finite element model is obtained by modeling the parts to be riveted in the assembly interference state. The finite element model can be used to predict the force applied to its surface and the process of predicting the influence of the structural offset in the model and the stress inside it. Due to the geometric error of the parts to be riveted, they interfere with the first assembly part or the second assembly part during the assembly process. In this case, it is necessary to obtain the structural characteristics of the parts to be riveted. By establishing a finite element model similar to the structure of the parts to be riveted, it is convenient to correspond the deformation degree and the applied force of the finite element model, so as to output the stress load corresponding to the parts to be riveted.

[0142] The characteristic dimensions of the riveted parts with geometric errors are length l, width w and height h. The local geometric model is intercepted from the combined overall geometric model with the position of the riveted parts as the center. The interfaces formed by the interception are S1, S2...Sm; and the characteristic dimensions of the local geometric model obtained by interception are length L, width W, and height H. The characteristic dimensions of the local geometric model and the characteristic dimensions of part 1 meet the following conditions: L≥2.5l, W≥2.5w, H≥2.5h.

[0143] Then, a finite element model is established according to the assembly interference state of the part to be riveted through the model generation module 610, so that the contact surface between the part to be riveted and the second assembly part fits together. At the same time, the part to be riveted overlaps with the first assembly part, and the overlapping part is the interference position of the part to be riveted. The reference interference amount between the part to be riveted and the first assembly part is obtained. The reference interference amount is expressed as δ0. The reference interference amount can be obtained by comparing the established geometric model, or by measuring the three-dimensional digital model under the interference state.

[0144] The model initialization module 620 is in communication connection with the model generation module 610 , and the model initialization module 620 is configured to obtain the first coordinates of the first rivet holes and add a connection unit to each of the second rivet holes.

[0145] The first coordinate is the coordinate of the first rivet hole in the assembly interference state. The value corresponding to the first coordinate is obtained by measuring the position of each first rivet hole in the finite element model. At the same time, a connection unit is added to the second connection hole through the model initial module 620. The contact property is set between the second connection part and the second assembly part through the connection unit, and the first connection part and the first assembly part are in a non-contact state.

[0146] Exemplarily, the connecting unit corresponds to a rivet passing through the second riveting hole, the connecting unit is set as a one-dimensional unit, and the connecting unit is used to ensure that the second connecting part and the second assembly part remain in a fitted state. At the same time, the size of the connecting unit is the same as the size of the rivet. The radius of the connecting unit is represented by r, and the length is represented by L'.

[0147] The coordinate acquisition module 630 is in communication connection with the model initialization module 620 , and is configured to acquire a second coordinate corresponding to the first rivet hole when the first connection portion is in a first preset state and the node force of the connection unit meets a preset condition.

[0148] The first preset state is a state in which the first connection portion of the corresponding finite element model reaches contact with the first assembly part. The stress load borne by the corresponding finite element model when it moves to the first preset state can be obtained by finite element analysis. At the same time, after the node force connected at the second rivet hole is judged by preset conditions, the second coordinate of the first rivet hole after the corresponding assembly is completed is obtained, which can facilitate the prediction of the load borne by the rivet in the first rivet hole and the second rivet hole to a certain extent, so as to improve the accuracy of predicting the load borne by the rivet used to connect the parts to be riveted.

[0149] The interference adjustment module 640 is in communication connection with the coordinate acquisition module 630 and the model initialization module 620; the interference adjustment module 640 is configured to obtain a displacement load according to the first coordinate and the second coordinate, and apply a corresponding displacement load to each of the first riveting holes.

[0150] The displacement load represents the external force that needs to be applied to eliminate the assembly interference state of the first connection part. At the same time, since the first connection part is connected to the first assembly part through the first rivet hole, the purpose of eliminating the assembly interference state of the first connection part can be achieved by applying a displacement load at the first rivet hole through the interference adjustment module 640.

[0151] The first coordinate corresponds to the first connection part in the interference state, and the second coordinate corresponds to the first connection part in the normal assembly state. The displacement load corresponding to the first connection part can be obtained through the first coordinate and the second coordinate. The displacement load is applied to each first rivet hole through the interference adjustment module 640, so that the first connection part is deformed to the normal installation state, so as to facilitate the subsequent measurement of the support reaction force at the first rivet hole and the second rivet hole, thereby improving the probability of obtaining the accuracy of the predicted load corresponding to the rivet on the part to be riveted after actual assembly.

[0152] The load output module 650 is in communication connection with the interference adjustment module 640 , and the load output module 650 is configured to obtain and output the support reaction force at each of the first rivet holes and the second rivet holes.

[0153] The support reaction force of the first rivet hole and the second rivet hole corresponding to the normal assembly state is obtained through the load output module 650. At the same time, the support reaction force at the first rivet hole and the second rivet hole is equivalent to the load borne by the rivet after the parts to be riveted are normally assembled, which can improve the accuracy of predicting the rivet load connected to the parts to be riveted.

[0154] In some embodiments, the present application further provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the aircraft rivet load prediction method of the above-mentioned various embodiments when executing the computer program.

[0155] In some embodiments, the present application further provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the aircraft rivet load prediction method of the above-mentioned various embodiments is implemented.

[0156] The present application can achieve the purpose of simplifying the predicted load of the interference parts of the complex aircraft parts by generating a finite element model based on the parts to be riveted. By obtaining the first coordinate of the first riveting hole corresponding to the initial state, adding a connecting unit to the second riveting hole, and making the first connecting part meet the first preset state, obtaining and judging whether the node force of the connecting unit in the corresponding second riveting hole meets the preset condition, and when the node force meets the preset condition, obtaining the second coordinate of the first riveting hole in the first state, and then calculating the displacement load of the corresponding first riveting hole through the first coordinate and the second coordinate; applying the displacement load to make the first connecting part reach the first preset state, adding the corresponding displacement load to each first riveting hole, and obtaining the corresponding support reaction force of the first riveting hole and the second riveting hole, the riveting load of the rivet corresponding to the part to be riveted is obtained, thereby improving the accuracy of obtaining the predicted load at the rivet, and also being able to evaluate the quality of the product after assembly, thereby achieving the purpose of ensuring the reliable assembly of parts.

[0157] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for predicting aircraft rivet loads, characterized in that: The method comprises the following steps: Generate a finite element model according to the structural features of the part to be riveted; wherein the part to be riveted includes a first connecting portion and a second connecting portion, the first connecting portion is provided with at least one first rivet hole for connecting with a first assembly part, and the second connecting portion is provided with at least one second rivet hole for connecting with a second assembly part; Acquire the first coordinates of the first rivet holes, and add a connection unit to each of the second rivet holes; When the first connection portion is in a first preset state and the node force of the connection unit meets a preset condition, acquiring a second coordinate corresponding to the first riveting hole; Acquire a displacement load according to the first coordinate and the second coordinate, and apply a corresponding displacement load to each of the first rivet holes; The riveting load is acquired and outputted, where the riveting load is the support reaction force at each of the first riveting hole and the second riveting hole.

2. The aircraft rivet load prediction method according to claim 1, characterized in that: The first preset state is a state in which the first connection portion is in contact with the first assembly part. Before the first connection portion is in the first preset state, the method further includes: The first connecting part is placed in a second preset state by applying an external force load to the first connecting part; wherein the external force load is configured to eliminate assembly interference of the first connecting part; when the first connecting part is in the second preset state, the first connecting part is separated from the first assembly part; Removing the external force load places the first connecting portion in a first preset state.

3. The aircraft rivet load prediction method according to claim 1, characterized in that: Before the node force of the connection unit meets a preset condition, the method further includes: Obtaining the allowable stress of the connection unit; wherein the allowable stress includes allowable tensile stress and allowable shear stress; Obtaining the node force of the connection unit, and converting the node force into the actual stress of the connection unit; wherein the actual stress is obtained by synthesizing the node force; The value of the actual stress is compared with the value of the allowable stress.

4. The aircraft rivet load prediction method according to claim 3, characterized in that: The preset condition is that the value of the actual stress is less than or equal to the value of the allowable stress; The allowable stress includes the allowable tensile stress and the allowable shear stress corresponding to the rivet being riveted at the second rivet hole.

5. The aircraft rivet load prediction method according to claim 4, characterized in that: After the step of comparing the value of the actual stress with the value of the allowable stress, the method further comprises: When the value of the actual stress is greater than the value of the allowable stress, removing the connection unit corresponding to the actual stress; Thereafter, when the first connection portion is in a first preset state and the node force of the connection unit meets a preset condition, the second coordinate corresponding to the first riveting hole is reacquired.

6. The method for predicting aircraft rivet loads according to any one of claims 1 to 5, characterized in that: Before the step of obtaining the first coordinates of the first rivet hole, the method further includes: Setting a reference point at the center of each of the first riveting holes; The first coordinate and the second coordinate are both obtained based on the coordinate of the reference point.

7. The aircraft rivet load prediction method according to any one of claims 1 to 5, characterized in that: The step of adding a connection unit to each of the second riveting holes comprises: Acquire an actual connection state corresponding to the second connection portion; wherein the actual connection state includes a position of the second rivet hole for connecting the rivet; A connecting unit is added to the second riveting hole at a corresponding position.

8. An aircraft rivet load prediction device, characterized in that: The device comprises: A model generation module (610) is configured to generate a finite element model according to the structural features of the part to be riveted; wherein the part to be riveted comprises a first connecting portion and a second connecting portion, the first connecting portion is provided with at least one first rivet hole for connecting with a first assembly part, and the second connecting portion is provided with at least one second rivet hole for connecting with a second assembly part; A model initialization module (620) is configured to obtain the first coordinates of the first rivet holes and add a connection unit to each of the second rivet holes; A coordinate acquisition module (630) is configured to acquire a second coordinate corresponding to the first riveting hole when the first connection portion is in a first preset state and the node force of the connection unit meets a preset condition; An interference adjustment module (640) is configured to obtain a displacement load according to the first coordinate and the second coordinate, and apply a corresponding displacement load to each of the first riveting holes; The load output module (650) is configured to obtain and output a riveting load, wherein the riveting load is a support reaction force at each of the first riveting holes and the second riveting holes.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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