Virtual vibration test method for engine fuel accessory

Abstract

The invention relates to the technical field of virtual vibration testing, and particularly discloses an engine fuel accessory virtual vibration testing method which comprises the following steps: S1, establishing a simulation database and a modeling tool library, and setting model material attributes and boundary conditions; s2, building a simulation model and test result comparison environment; and S3, searching an optimal position and an optimal method of the control point. According to the engine fuel accessory virtual vibration test method, an aero-engine fuel control system accessory is used as an object, and a virtual vibration test platform is used; various vibration conditions of accessories are simulated in a simulation environment, main factors (unreasonable vibration clamp design, unreasonable control point selection and unreasonable structure design) influencing vibration test failure are eliminated in a simulation stage, the factors are prevented from flowing into manufacturing and testing links, time and economic cost are saved, model vibration test success is assisted, and the test efficiency is improved. And the one-time success rate of a power-assisted vibration test reaches 93.94%.

Description

Technical Field

[0001] The invention relates to the technical field of virtual vibration testing, and in particular to a virtual vibration testing method for engine fuel accessories. Background Art

[0002] Virtual vibration test technology is a method of simulating the vibration behavior of real objects in a computer environment. By studying high-precision modeling technology, simulation correction technology, and optimal control strategy technology, a virtual vibration test platform is built as a research carrier and tool for virtual vibration test technology.

[0003] The components of the aircraft engine fuel control system are very complex in structure and need to have strong vibration resistance to meet the strength assessment requirements. Vibration test is the most critical environmental mechanical test for assessing structural strength. Figure 2 As shown in the figure, statistics of vibration test data from 2019 to 2022 show that the success rate of vibration tests is less than 50%. Analysis of the reasons for failure shows that 84% of the failures are due to three aspects: first, the design of the vibration test fixture is unreasonable; second, the vibration test method (control point selection) is unreasonable; third, the structural strength of the test piece itself does not meet the requirements. Faced with the current situation of increasing model development tasks and tight time, it is imperative to improve the success rate of vibration tests and ensure that the success rate of the test is not less than 90%.

[0004] For example Figure 3 The three simulation methods shown clearly show that the conventional vibration simulation method does not introduce the influence of the vibration table, resulting in a large error between the calculated results and the test data. By comparing the consistency between the simulation results and the test results, it can be seen that by considering the vibration table and further detailing the modeling parameters, a more accurate simulation of the product's response in a vibration environment can be achieved. Therefore, it is very important to carry out research on virtual vibration test technology. Summary of the invention

[0005] The purpose of the present invention is to provide a virtual vibration test method for engine fuel accessories, which can eliminate the main factors affecting the failure of vibration test (irrational vibration fixture design, unreasonable control point selection, unreasonable structural design) in the simulation stage, avoid flowing into the manufacturing and testing links, and save time and economic costs.

[0006] To achieve the above object, the present invention provides a virtual vibration test method for an engine fuel accessory, comprising the following steps:

[0007] S1. Establish simulation database, modeling tool library, and set model material properties and boundary conditions;

[0008] S2, build a simulation model and test results comparison environment;

[0009] S3. Find the optimal position and method of control points.

[0010] Preferably, S1 specifically establishes a mechanical property library of special materials for aviation fuel accessories; and models a bolt connection setting tool for rapid calculation and setting of bolt preload.

[0011] Preferably, in S1, during modeling, the vibration table body is set as a rigid body model, and the table top is set as a flexible body model. The vibration table body and the table top are connected by a movable pair. The distributed mass of the table top can be increased due to model simplification. The connection relationship between the table body and the table top is established by adding spring units, and a finite element model of the vibration table support is established.

[0012] Preferably, S2 specifically includes the following steps:

[0013] S21. Input test data, form deviation values, perform modeling parameter sensitivity analysis and model optimization, and improve the confidence of vibration simulation response;

[0014] S22. With the goal of reducing the deviation of vibration results, select the modeling parameters that have a greater impact on the results, and iterate and correct them to automatically display the error between the parameter correction results, simulation results and test data.

[0015] Preferably, in S22, the vibration results include frequency, displacement and acceleration amplitude, and the modeling parameters include spring support stiffness, damping and material properties.

[0016] Preferably, the specific process of S3 is as follows:

[0017] Output the response list of pre-selected control points, determine the maximum response, minimum response, average response and node position of the pre-selected control points, output the vibration response value of any node in the model, and determine the size of the vibration response value of the selected node, and find the optimal position and optimal method of the control point through the vibration control implementation method.

[0018] Preferably, the vibration control includes maximum value control, minimum value control and weighted average control.

[0019] Therefore, the present invention adopts the above-mentioned virtual vibration test method for engine fuel accessories, and the beneficial effects are as follows:

[0020] (1) The present invention takes the accessories of the fuel control system of an aircraft engine as the object, uses a virtual vibration test platform, and simulates various vibration conditions of the accessories in a simulation environment. For the accessories themselves, a three-dimensional model is obtained through high-precision modeling technology. The displacement, acceleration, strain and other result data of key positions on the accessories can be obtained by simulation, which provides an important basis for the analysis and optimization of the accessory structure.

[0021] (2) The method provided by the present invention can simulate the installation environment of the accessory on the engine as much as possible for the vibration test fixture, thereby ensuring the correctness of the test fixture.

[0022] (3) For vibration tests, the method provided by the present invention determines the position of the vibration test control point through the optimal control strategy technology, thereby ensuring the authenticity of the acceleration amplitude response result data at the key position on the accessory.

[0023] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is an overall flow chart of an embodiment of a virtual vibration test method for an engine fuel accessory of the present invention;

[0025] Figure 2 It is a project background diagram of the background technology of a virtual vibration test method for engine fuel accessories of the present invention, wherein (a) is a statistical diagram of the causes of failure of vibration tests, and (b) is a diagram of improving the success rate of vibration tests in one time;

[0026] Figure 3 It is a schematic diagram of the virtual vibration test reason of a virtual vibration test method background technology of an engine fuel accessory of the present invention, wherein (a) is a virtual vibration test without considering the vibration table and under default binding, (b) is a virtual vibration test with considering the vibration table and under default binding, (c) is a virtual vibration test with considering the vibration table and detailed modeling parameters, (d) is a virtual vibration test response curve, and (e) is a virtual vibration test simulation and experimental result consistency comparison result;

[0027] Figure 4 Schematic diagram of virtual vibration failure factors of an embodiment of a virtual vibration test method for an engine fuel accessory of the present invention, wherein (a) is a high confidence modeling technology, (b) is a founder correction technology, and (c) is an optimization control strategy technology;

[0028] Figure 5 1 is a schematic diagram of parameterization of a virtual vibration table model of an embodiment of a virtual vibration test method for an engine fuel accessory of the present invention, wherein (a) is a mechanical property library of 140 special materials for aviation fuel accessories established, (b) is a bolt connection setting tool, (c) is a welding connection setting tool, (d) is a contact setting tool, and (e) is a schematic diagram of vibration table parameter modeling;

[0029] Figure 6 It is a schematic diagram of the calibration of the virtual vibration test bench actual measurement and virtual test parameters in an embodiment of the virtual vibration test method for engine fuel accessories of the present invention, wherein (a) is a physical modal test diagram of the vibration test bench, (b) is a schematic diagram of the calibration result comparison process, and (c) is a schematic table of the test frequency interpolation method;

[0030] Figure 7It is a schematic diagram of comparison between a virtual vibration test bench and measured modal data of an embodiment of a virtual vibration test method for an engine fuel accessory of the present invention;

[0031] Figure 8 It is a schematic diagram of a simulation correction process based on measured data of an embodiment of a virtual vibration test method for an engine fuel accessory of the present invention, wherein (a) is a flow chart, and (b) is a schematic diagram of RLB fuel pump sweep frequency simulation-experimental consistency comparison test results;

[0032] Fig. 9 It is a schematic diagram of an engine fuel accessory virtual vibration test method embodiment of the present invention, which guides the rapid selection of the optimal position of the control point and the optimal control method;

[0033] Fig.10 1 is a hierarchical decomposition diagram of a virtual experimental object of a first embodiment of a virtual vibration test method for an engine fuel accessory of the present invention, wherein (a) is a first-level decomposition diagram, and (b) is a second-level decomposition diagram;

[0034] Fig.11 It is a simulation diagram of the contact surface of the bushing unit fixture in the first embodiment of the virtual vibration test method for the engine fuel accessories of the present invention;

[0035] Fig.12 It is a modeling diagram of a bolt connection unit in Embodiment 1 of a virtual vibration test method for an engine fuel accessory of the present invention;

[0036] Fig.13 It is a beam unit modeling diagram of a simulated bolt connection in Embodiment 1 of a virtual vibration test method for engine fuel accessories of the present invention, wherein (a) is a simulation diagram of the connection screws between the fixture flange and the center vertical plate, and (b) is a simulation diagram of the connection screws between the fixture bottom plate and the vertical plate;

[0037] Fig.14 It is a fixture beam modeling diagram of embodiment 1 of a virtual vibration test method for an engine fuel accessory of the present invention, wherein (a) is a beam unit modeling diagram when R=11 mm, and (b) is a beam unit modeling diagram when R=7 mm;

[0038] Fig.15 It is a schematic diagram of modal parameter extraction based on Polymax in Embodiment 1 of a virtual vibration test method for an engine fuel accessory of the present invention;

[0039] Fig.16 It is a schematic diagram of a modal confidence criterion MAC matrix of a first embodiment of a virtual vibration test method for an engine fuel accessory of the present invention;

[0040] Fig.17It is a schematic diagram of a simulated modal vibration shape of a fuel pump fixture in Embodiment 1 of a virtual vibration test method for engine fuel accessories of the present invention;

[0041] Fig.18 It is a schematic diagram of parameter correction results of a first embodiment of a virtual vibration test method for an engine fuel accessory of the present invention;

[0042] Fig.19 It is a schematic diagram of modal correction of a first embodiment of a virtual vibration test method for an engine fuel accessory of the present invention;

[0043] Fig. 20 It is a schematic diagram of the sweep frequency vibration results of the first embodiment of a virtual vibration test method for an engine fuel accessory of the present invention;

[0044] Fig.21 It is a schematic diagram of a virtual-real comparison curve of measuring point 3 in Embodiment 1 of a virtual vibration test method for an engine fuel accessory of the present invention;

[0045] Fig. 22 It is a schematic diagram of random vibration PSD spectrum extraction of a first embodiment of a virtual vibration test method for an engine fuel accessory of the present invention;

[0046] Fig.23 It is a schematic diagram of linear representation of random vibration PSD spectrum of embodiment 1 of a virtual vibration test method for engine fuel accessories of the present invention;

[0047] Fig.24 It is a schematic diagram of virtual-real comparison of random power spectrum density in Embodiment 1 of a virtual vibration test method for engine fuel accessories of the present invention;

[0048] Fig.25 It is a schematic diagram of setting up a high-order unit in Embodiment 1 of a virtual vibration test method for an engine fuel accessory of the present invention;

[0049] Fig.26 It is a schematic diagram of contact algorithm setting of a first embodiment of a virtual vibration test method for an engine fuel accessory of the present invention;

[0050] Fig. 27 1 is a schematic diagram of the equivalent connection of a model of a first embodiment of a virtual vibration test method for an engine fuel accessory of the present invention, wherein (a) is a schematic diagram of the equivalent connection of a beam unit with R=2.2m, and (b) is a schematic diagram of the equivalent connection of a beam unit with R=3m;

[0051] Fig.28It is a schematic diagram of a modal vibration shape distribution list of embodiment 1 of a virtual vibration test method for an engine fuel accessory of the present invention, wherein (a) is a first-order modal vibration shape distribution list, (b) is a second-order modal vibration shape distribution list, (c) is a third-order modal vibration shape distribution list, (d) is a fourth-order modal vibration shape distribution list, (e) is a fifth-order modal vibration shape distribution list, and (f) is a sixth-order modal vibration shape distribution list. DETAILED DESCRIPTION

[0052] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0053] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0054] In order to help the vibration test succeed once, the main factors that affect the failure of the vibration test are eliminated in the calculation stage to avoid flowing into the manufacturing and testing links, saving time and economic costs. We have specially carried out research on virtual vibration test technology and built a virtual vibration test platform to break the lag of physical verification; improve the accuracy of "product level → fixture level → vibration system level" digital model calculation to ensure the confidence of vibration simulation; output the pre-selected control point response list to guide the rapid selection of the optimal position of the control point and improve the confidence of the vibration test implementation. See the key technical content for details. Figure 4 .

[0055] In order to eliminate the problems of unreasonable structural design, unreasonable fixture design, unreasonable control point selection, etc., the confidence of vibration simulation and vibration implementation is improved. The present invention establishes and integrates simulation models of vibration table, fixture and product through software environment, and completes the vibration environment test tasks that are the same or similar to the physical vibration test through multidisciplinary joint simulation technology. It mainly involves three aspects: the first is the virtualization of the test means, that is, the instruments and equipment required for the test; the second is the virtualization and simulation of the test object; the third is the virtualization and simulation of the test environment.

[0056] The virtual vibration test platform software is used to conduct vibration test simulation analysis, test result prediction, and test model correction on the tested object to enhance the product forward design and development capabilities. By conducting vibration test simulation of the tested object (including products, fixtures, etc.) model, and through model verification, sensitivity analysis, parameter correction and other methods, the confidence of the virtual vibration test results is improved to guide the vibration simulation analysis and technical research of the product. The research results are mainly used for vibration test simulation of aviation engine fuel control system accessories, to assist product forward design and development, and to achieve a successful product vibration test in one go.

[0057] In the research of high-confidence modeling technology, on the one hand, by establishing a simulation database, a library of mechanical properties of more than 140 types of special materials for aviation fuel accessories was formed. At the same time, various modeling tools were developed to realize functions such as rapid calculation and setting of bolt preload, rapid establishment of assembly welding, and automatic identification of gap detection, further improving the model's material properties, boundary conditions and other key factors. On the other hand, the parametric modeling of the vibration table was completed to identify the risks of coupling between the vibration table and the assembly, so as to more accurately simulate the vibration response of the product and increase the confidence level to more than 95%.

[0058] On the other hand, in the research of simulation correction technology for measured data, by building a simulation model and comparing the test results, inputting the test data, and performing correlation error calculation, a deviation value is formed. With the goal of reducing the deviation value, the modeling parameter sensitivity analysis and model optimization are automatically performed to achieve iterative correction and improve the confidence of vibration simulation response.

[0059] In the research on optimal control strategy technology, a new function of outputting the response list of pre-selected control points has been added, and the maximum response, minimum response, average response and node position of the pre-selected control points have been automatically determined. Combined with the vibration control implementation method (maximum value control, minimum value control, weighted average control), it guides the selection and optimization of control points and the implementation of control methods.

[0060] The technical requirements for virtual vibration testing, the development of virtual vibration testing research technical tools (virtual vibration testing platform), modal testing and virtual vibration testing research of test objects (virtual vibration testing platform, typical pump products, typical regulator products), comparison and optimization of virtual test results with physical tests, etc. have been completed. The technical methods of each link of virtual testing have been solidified and applied in practice to form a research result - virtual vibration test specification. 33 vibration tests have been carried out in 2023-2024, and virtual vibration test technology has been successfully used in more than 20 vibration tests, helping the first-time success rate of vibration tests reach 93.94%.

[0061] like Figure 1 As shown, a virtual vibration test method for an engine fuel accessory comprises the following steps:

[0062] High confidence modeling

[0063] S1. Establish a simulation database and modeling tool library, set and improve key factors such as model material properties and boundary conditions, specifically establish a mechanical property library for 140 types of aviation fuel accessories; model bolt connection setting tools to achieve rapid calculation and setting of bolt preload. Identify the resonance coupling effect of the vibration table on the product vibration test; more accurately simulate the response of the product in a vibration environment, with a confidence level of ≥95%, such as Figure 5 shown.

[0064] During modeling, the vibration table body is set as a rigid model (rigid), the table top is set as a flexible model (Flexible), the vibration table body and the table top are connected by a translational pair (Translational), and the table top can increase the distributed mass due to model simplification. By adding spring units (spring-element), the connection between the table body and the table top can be established, and the vibration table support finite element model can be established. In this way, the guide support, coil electromagnetic force, and lower introductory air chamber support on the vibration table are simulated. In order to ensure the accuracy of the simulation results, it is necessary to conduct physical tests on the vibration table dynamic coil to obtain modal data, such as Figure 6-Figure 7 shown.

[0065] Through the above method, the modal consistency between the vibration table dynamic coil model and the physical vibration table dynamic coil is achieved, and the model connection parameters, equivalent mass, vibration table air spring stiffness, etc. are calibrated. This is the basis and prerequisite for ensuring the confidence of the virtual vibration response quantity in the next step.

[0066] Simulation correction based on measured data

[0067] S2. Build a simulation model and test result comparison environment, which specifically includes the following steps:

[0068] S21. Input test data, form deviation values, automatically perform modeling parameter sensitivity analysis and model optimization, and improve the confidence of vibration simulation response;

[0069] S22, with the goal of reducing the deviation of vibration results, the vibration results include frequency, displacement and acceleration amplitude; screen the modeling parameters that have a greater impact on the results, the modeling parameters include spring support stiffness, damping and material properties, iterative correction automatically displays the parameter correction results, the error between the simulation results and the test data. After correction, the confidence level of a fuel pump vibration response reached 98.6%. The specific test process is shown in Figure 8 .

[0070] S3, find the optimal position and optimal method of the control point. The specific process is as follows:

[0071] Output the response list of pre-selected control points, automatically determine the maximum response, minimum response, average response and node position of the pre-selected control points, guide the selection and optimization of control points and the implementation of control methods, output the vibration response value of any node in the model, and automatically determine the size of the vibration response value of the selected node. By combining the vibration control implementation method, guide the rapid search for the optimal position and optimal method of the control point. Vibration control includes maximum value control, minimum value control and weighted average control. The specific process is shown in Fig. 9 .

[0072] Embodiment 1

[0073] The application analysis is explained by taking the virtual vibration confidence improvement of a fuel pump as an example. The test object, a fuel pump, is divided into layers, such as Fig.10 shown.

[0074] 1. Improvement of fixture modal confidence

[0075] Since the use of common node modeling will lead to excessive connection stiffness, which will cause the simulation results to be inconsistent with the experimental test, as shown in Table 1 and Table 2, Figure 11-Figure 14 As shown in the figure, the Bushing unit is considered for modeling. The Bushing unit provides connection stiffness in six directions, where Kx, Ky and Kz are stiffness in the x-direction, y-direction and z-direction respectively, and Rx, Ry and Rz are stiffness around the x-axis, y-axis and z-axis respectively. The contact characteristics of the fixture are simulated by adjusting the connection stiffness. The bolt connection is equivalent to the beam188 beam unit.

[0076] Table 1 Beam unit modeling parameters

[0077] Serial number Kx(N / mm Ky(N / mm) Kz(N / mm) Rx(N / mm) Ry(N / mm) Rz(N / mm) Bushing_1 <![CDATA[5e 5 ]]> <![CDATA[5e 5 ]]> <![CDATA[5e 5 ]]> <![CDATA[5e 5 ]]> <![CDATA[5e 5 ]]> <![CDATA[5e 5 ]]> Bushing_2 5e5 5e5 5e5 5e5 5e5 5e5

[0078] Table 2 Beam unit modeling parameters

[0079] Serial number Parameter name Bolt diameter(mm) R(mm) 1 R_1 M10 5 2 R_2 M12 6 3 R_3 M20 11

[0080] The modal parameters of the frequency response curves of each measuring point of the fixture are extracted based on polynomials, and the curves are smoothed, such as Fig.15 The modal test frequency and damping results of a fuel pump fixture are shown in Table 3.

[0081] Table 3 Test results list

[0082] Degree Modal frequency (Hz) Damping ratio % Degree Modal frequency (Hz) Damping ratio % 1 807.371 0.38 6 2051.829 0.61 2 1010.504 0.34 7 2185.807 0.71 3 1301.716 0.38 8 2480.512 0.77 4 1352.081 0.37 9 2976.613 0.40 5 1783.083 0.92 10 3285.451 0.22

[0083] The test vibration results of each order are as follows: Fig.16 As shown in the figure, it can be seen from the MAC matrix that the maximum MAC value between each mode is 0.56, which proves that each mode is independent of each other, the test quality is good, and the result is credible.

[0084] Simulation and test modal correlation analysis. Based on the modal correction software module, the simulation results and test results are analyzed for correlation. The simulation model file and the test result file are imported into the modal correction software module to calculate the correlation between the two. Fig.17 is the simulation mode matrix.

[0085] Based on the MAC vibration correlation algorithm and frequency deviation algorithm, the consistency of the two is calculated. The calculation results are shown in the following table. It can be seen that the deviation of the two frequencies is within 5%. The vibration consistency is greater than 95%. The two have good consistency. No model correction is required.

[0086] Parameter model correction, after completing a sensitivity analysis, perform FEA finite element model correction. Model correction can continue to use the correction parameters and correction targets set during sensitivity analysis, or modify the new parameter settings and then perform model correction. After setting the number of correction iterations, errors and correction algorithms, click "Start" to correct the finite element model. Generally, the default parameter settings can meet the requirements for model correction, or they can be manually modified according to actual needs. The model correction results include: a three-dimensional histogram of the MAC matrix of the data after model correction, the convergence curves of each correction parameter in each correction iteration process, the convergence curves of each corrected modal frequency in each correction iteration process, a list of changes in correction parameters, and a list of corrected modal frequencies and MAC values ​​and a corrected MAC matrix, such as Fig.18 , Fig.19 The frequency error Diff (difference) of finite element simulation analysis FEA and laboratory modal analysis EMA is shown in the following table:

[0087] Table 4 Comparison between simulation and experiment

[0088] Serial number FEA Hz EMA Hz Diff(%) 1 801.74 807.37 -0.7 2 2 1045.24 2 1010.5 3.44 3 3 1309.29 3 1301.72 0.58 4 4 1363.55 4 1352.1 0.85 5 5 1798.83 5 1783.1 0.88 6 6 2317.1 6 2185.8 6.01 7 7 2501.28 7 2480.5 0.84 8 8 3017.78 8 2976.6 1.38

[0089] Through correction, the modal frequencies of a fuel pump fixture are within 3.5% except for the sixth order, the error of the sixth order is 6.01%, and all frequencies within 2000Hz are within 5% of the target value.

[0090] 2. Improved confidence in fixture virtual vibration testing

[0091] Fixture sweep frequency test. According to the test standard, the load condition of a fuel pump fixture sweep frequency vibration test is: 5~2000Hz. Acceleration 2g sweep frequency. According to the control response spectrum, the actual load is inverted - sweep frequency vibration analysis is performed - electrical, such as Fig. 20 shown.

[0092] Comparison between frequency response fixture sweep vibration simulation and test. Compare the simulation results of the monitoring point data of interest (i.e., the data collected by sensor 3) with the test requirements: the acceleration response at the first-order and second-order frequencies is within the 10% error range, as shown in Table 5 below:

[0093] Table 5 Error comparison between simulation results and test results

[0094] frequency test simulation error 148Hz 10.439g 10.751g 2.99％ 603Hz 9.903g 10.388g 4.67％

[0095] Fixture random vibration test according to Fig. 22 The PSD response curve of a fuel pump fixture is as follows: Fig.23 As shown: the output PSD curves in the range of 5-500Hz are smooth and have good transmission efficiency.

[0096] Comparison between fixture random vibration simulation and test. Consistent with the test, the power spectrum density function of the corresponding measurement point is output in the simulation model and the two are compared, such as Fig.24 shown.

[0097] The above DataMaching tool is used to compare and analyze the virtual and real curves. The consistency correlation coefficient of the random PSD curve is 0.945 and the standard deviation is 0.055. When a fuel pump fixture is subjected to random vibration, the power spectrum density of the reference spectrum can be transmitted to the product without loss. The results of the random vibration simulation parameters set above can accurately predict the random vibration response of a fuel pump fixture.

[0098] 3. Improvement of modal confidence of a fuel pump

[0099] A fuel pump free modal test. In terms of model simplification and geometric cleanup, there are some small fillets on the fuel pump product, which affect the size of the mesh division. In order to divide the high-quality mesh, the geometric cleanup is verified to remove the influence of these small fillets and other tiny features on the modal results, and remove the hole chamfers and fillets and right angles less than or equal to 2mm. Based on previous modal simulation experience, the second-order unit is directly selected for simulation analysis, such as Fig.25 shown.

[0100] Contact setting: The internal parts of the fuel pump are installed using the bonded contact setting (Bonded), and the MPC multi-point contact algorithm is used for contact calculation, such as Fig.26 shown.

[0101] A fuel pump assembly is fixed with bolts. Its finite element modeling uses Beam units to model the equivalent connection of the model by adjusting the bolt connection diameter. Fig. 27 shown.

[0102] The list of modeling parameters is as follows:

[0103] Table 6 Beam unit modeling parameters

[0104] Serial number Parameter name Bolt diameter(mm) R(mm) 1 R_5 M6 3 2 R_6 M4 2.2 3 R_7 M4 2.2

[0105] Modal results of a fuel pump:

[0106] Table 7 Modal frequency list

[0107] Degree Frequency (Hz) Degree Frequency (Hz) 1 629.31 4 1720.4 2 850.27 5 1782 3 1090.4 6 2056.8

[0108] After the constraint modal calculation of a fuel pump fixture is completed, the post-processing results are extracted as follows Fig.28 As shown, the modal analysis of the product is compared with the test modal consistency, and the natural frequency comparison list and test frequency are as follows:

[0109] Table 8 Comparison with test results

[0110] Serial number Simulation(Hz) Test (Hz) error(%) 1 629.31 630.12 0.129 2 850.27 895.837 4.015 3 1090.4 1073.98 -1.529 4 1720.4 1698..80 -1.271 5 1782 1769.433 -0.710 6 2056.8 2022.86 -1.678

[0111] Constrained modal test of a fuel pump. The constrained modal test of a fuel pump is installed with a fixture and fixedly connected to the fixture through a clamp. The fixture and the vibration table are fixed by bolts. The constrained modal analysis uses a fixed vibration table fixed coil, and the moving coil is connected to the fixture. The model uses free meshing, and the mesh size Size = 5mm.

[0112] Therefore, the present invention adopts the above-mentioned virtual vibration test method for engine fuel accessories to eliminate the main factors affecting the failure of the vibration test (unreasonable vibration fixture design, unreasonable control point selection, unreasonable structural design) in the simulation stage, avoiding flowing into the manufacturing and testing links, saving time and economic costs.

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A virtual vibration test method for engine fuel accessories, characterized in that: Includes the following: S1. Establish simulation database, modeling tool library, and set model material properties and boundary conditions; S2, build a simulation model and test results comparison environment; S3. Find the optimal position and method of control points.

2. The virtual vibration test method for engine fuel accessories according to claim 1 is characterized in that: S1 is specifically for establishing a mechanical property library of special materials for aviation fuel accessories; modeling bolt connection setting tools for rapid calculation and setting of bolt preload.

3. The virtual vibration test method for engine fuel accessories according to claim 2 is characterized in that: In S1, the vibration table body is set as a rigid body model, and the table top is set as a flexible body model during modeling. The vibration table body and the table top are connected by a moving pair. The distributed mass of the table top can be increased due to model simplification. The connection relationship between the table body and the table top is established by adding spring units, and the vibration table support finite element model is established.

4. The virtual vibration test method for engine fuel accessories according to claim 3 is characterized in that: S2 specifically includes the following steps: S21. Input test data, form deviation values, perform modeling parameter sensitivity analysis and model optimization, and improve the confidence of vibration simulation response; S22. With the goal of reducing the deviation of vibration results, select the modeling parameters that have a greater impact on the results, and iterate and correct them to automatically display the error between the parameter correction results, simulation results and test data.

5. The virtual vibration test method for engine fuel accessories according to claim 4 is characterized in that: In S22, the vibration results include frequency, displacement and acceleration amplitude, and the modeling parameters include spring support stiffness, damping and material properties.

6. The virtual vibration test method for engine fuel accessories according to claim 5 is characterized in that: The specific process of S3 is as follows: Output the response list of pre-selected control points, determine the maximum response, minimum response, average response and node position of the pre-selected control points, output the vibration response value of any node in the model, and determine the size of the vibration response value of the selected node, and find the optimal position and optimal method of the control point through the vibration control implementation method.

7. The virtual vibration test method for engine fuel accessories according to claim 6 is characterized in that: The vibration control includes maximum value control, minimum value control and weighted average control.

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