Rotor vibration outbound coefficient design method based on bearing dynamic strain test data

Abstract

The invention provides a rotor vibration outbound coefficient design method based on support dynamic strain test data. The method comprises the following steps: step 1, carrying out support structure deformation calculation considering bolt connection; step 2, carrying out deformation calculation on the rigidly connected supporting structure; step 3, acquiring a connection rigidity correction coefficient according to the step 1 and the step 2; step 4, according to the connection rigidity correction coefficient, obtaining an average stress calculation result at the patch; step 5, according to a result of the step 4, obtaining an average stress measurement result of the patch and engine external vibration actual measurement data; step 6, obtaining a vibration load of the rotor supporting structure; and 7, calculating a rotor vibration outward transmission coefficient according to the vibration load of the rotor supporting structure. According to the method, the mathematical relationship between the vibration load borne by the rotor support and the vibration response of the external casing of the engine is established, a technical approach can be provided for quantitative evaluation of the safety of the support structure of the engine and quantitative prediction of the external vibration response, and the method has practical engineering significance for the safety design of the aero-engine.

Description

Technical Field

[0001] The invention relates to the technical field of aeroengines, and in particular to a method for designing a rotor vibration transmission coefficient based on support dynamic strain test data. Background Art

[0002] Aircraft engines are characterized by high load, high speed and light weight. When encountering severe working conditions such as blade loss and foreign object damage, the safety of the supporting structure becomes the key to determining the survivability of aircraft engines. Under the extreme state of blade loss, the rotor system of the aircraft engine is subjected to impact loads and large unbalanced loads. The loads are transmitted to the supporting structure through the rotor structure, causing serious damage to the supporting structure and seriously threatening the bearing capacity of the supporting structure. Therefore, it is necessary to study the safety of the supporting structure of the aircraft engine bearing-support structure under extreme loads.

[0003] At present, there are few studies on the quantitative evaluation of the safety of the support structure. The difficulty lies in the fact that due to space limitations, the load of the engine support structure is usually difficult to obtain. For aircraft engines, loads such as unbalanced excitation during the operation of the rotor are transmitted to the external casing, mounting joints, etc. through the rotor fulcrum and load-bearing frame. The vibration response at the casing is usually installed with monitoring sensors and is easy to obtain. However, the internal vibration load of the rotor support structure is difficult to obtain in the whole machine state. This paper provides a method for evaluating the rotor vibration transmission coefficient based on the support dynamic strain test data. Using this method, on the one hand, the rotor support load can be obtained by inversely deducing the external vibration of the casing that is easily measured, so as to perform a quantitative evaluation of the safety of the support structure; on the other hand, the external vibration response of the engine can be predicted through the actual load of the rotor support structure or the simulation data of the rotor unbalance response, which has practical engineering significance for the safety design of the aircraft engine support structure. Summary of the invention

[0004] In view of this, the present invention provides a method for designing the rotor vibration transmission coefficient based on the support dynamic strain test data, so as to provide technical support for the quantitative evaluation of the safety of the engine support structure and the quantitative evaluation and prediction of the external vibration response.

[0005] The present invention provides the following technical solution: a method for designing a rotor vibration transmission coefficient based on support dynamic strain test data, comprising: step 1, performing support structure deformation calculation considering bolt connection; step 2, performing support structure deformation calculation of rigid connection; step 3, obtaining a connection stiffness correction coefficient according to step 1 and step 2; step 4, obtaining an average stress calculation result at a patch according to the connection stiffness correction coefficient; step 5, obtaining an average stress measurement result at the patch and actual engine external vibration data according to the result of step 4; step 6, obtaining a rotor support structure vibration load; step 7, calculating a rotor vibration transmission coefficient according to the rotor support structure vibration load.

[0006] Furthermore, step 1 is specifically as follows: Establish a finite element model of the supporting structure with bolted connections; Apply load to the finite element model of the support structure with bolt connection to perform static strength calculation, obtain the first deformation result of the support structure, and obtain the first deformation S away from the load application position and displacement constraint position 1 .

[0007] Furthermore, step 2 is specifically as follows: Use rigid connection to replace bolt connection and establish finite element model of rigid connection supporting structure; Apply load to the finite element model of the rigidly connected support structure to perform static strength calculation, obtain the second deformation result of the support structure, and obtain the second deformation S away from the load application position and displacement constraint position. 2 And the initial elastic modulus of the material at the rigid connection location .

[0008] Furthermore, step 3 is specifically as follows: Change the elastic modulus of the rigid connection position, apply load and perform static strength iteration calculation until , obtain the material elastic modulus of the rigid connection position at this time ; By formula Get the connection stiffness correction factor .

[0009] Furthermore, step 4 is specifically as follows: Considering the connection stiffness correction coefficient, the elastic modulus of the material at the bolt connection position is corrected, and the rigid connection finite element model of the supporting structure at different support points is established; Apply the rotor lateral vibration load F to perform simulation calculations and obtain the stress distribution results of the supporting structure; According to the stress distribution results of the supporting structure, select the finite element nodes within the range of the strain gauge patch position grid; The average stress of the finite element node is used to calculate the average stress at the support structure patch. .

[0010] Furthermore, step 5 is specifically as follows: The actual vibration response data of the casing is measured by vibration test equipment ; By formula , get the average stress measurement result at the patch ,in, is the dynamic strain data of the support, and E is the mechanical property data of the material.

[0011] Furthermore, step 6 is specifically as follows: According to the formula , obtain the vibration load of the rotor support structure , F is the rotor lateral vibration load.

[0012] Furthermore, step 6 is specifically as follows: By formula Get the single rotor vibration transmission coefficient ; By formula , and the final rotor vibration transmission coefficient is obtained .

[0013] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above-mentioned technical solutions adopted by the present invention include at least the following: the present invention establishes a mathematical relationship between the vibration load borne by the rotor support and the vibration response of the external casing of the engine, which can provide a technical approach for the quantitative evaluation of the safety of the engine support structure and the quantitative prediction of the external vibration response, and has practical engineering significance for the safety design of aircraft engines. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 It is a flowchart of an embodiment of the present invention.

[0016] Figure 2 Schematic diagram of patch positions according to an embodiment of the present invention. DETAILED DESCRIPTION

[0017] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0018] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0019] like Figure 1 As shown, an embodiment of the present invention provides a method for designing a rotor vibration transmission coefficient based on support dynamic strain test data, which specifically includes the following steps: Step 1 Consider the deformation calculation of the support structure with bolt connection. Consider the influence of bolt connection on the rigidity of the engine casing and establish a finite element model of the support structure with bolt connection. Apply a force F of magnitude to the rotor support structure model. 0 The static strength calculation is performed with the load to obtain the deformation result of the supporting structure and record the deformation of the calculation model away from F. 0 Deformation at the load application location and displacement constraint location .

[0020] Among them, the original geometric model of the bolt entity needs to remove the threads and chamfers to simplify the bolt; in the finite element model, rigid connections are used between the screw and the connector, the nut and the connector, and the nut and the screw, and friction contact is used between the contact surfaces of the connector.

[0021] Step 2: Calculate the deformation of the rigidly connected support structure. Remove the bolts and replace the bolted connection with a rigid connection to establish a finite element model of the rigidly connected support structure. Apply a force F of magnitude to the rotor support structure model. 0 Perform static strength calculation on the load to obtain the deformation result of the supporting structure and record the deformation at the same position as step 1 and the initial elastic modulus of the material at the rigid connection position .

[0022] Step 3: Calculate the connection stiffness correction factor. For the finite element model of the rigidly connected supporting structure, change the elastic modulus of the connection part and apply a value of F 0 The load is iterated until , record the elastic modulus of the material at the rigid connection position at this time . Connection stiffness correction factor .

[0023] Step 4 obtains the average stress calculation result at the patch. Considering the connection stiffness correction coefficient, the material elastic modulus at the bolt connection position is corrected, and a rigid connection finite element model of the support structure at different fulcrums is established. Then the rotor lateral vibration load F is applied for simulation calculation to obtain the stress distribution result of the support structure. According to the finite element simulation stress distribution result of the support structure, the finite element nodes within the grid range of the strain gauge patch position are selected, and the average stress of the finite element nodes in these areas is calculated to obtain the average stress calculation result at the support structure patch. .

[0024] Step 5: Obtain the average stress measurement results at the patch and the actual measured data of the engine external vibration. Paste the strain gauge on the support structure at the rotor fulcrum, and measure the dynamic strain data of the support through the strain testing equipment. Install a vibration sensor on the engine casing and use vibration test equipment to measure the actual vibration response data of the casing. According to the dynamic strain test results of the supporting structure and the mechanical properties data of the material, the stress-strain theory formula is used , get the average stress measurement result at the patch , E is the mechanical properties data of the material.

[0025] Step 6 Obtain the vibration load of the rotor support structure. Based on the stress measurement results at the support patch and the support deformation simulation calculation results, the vibration load of the rotor support structure is calculated. , the calculation formula is , F is the rotor lateral vibration load.

[0026] Step 7 Calculate the rotor vibration transmission coefficient. According to the vibration load of the rotor support structure , and the corresponding measured vibration response data of the casing , calculate the single rotor vibration transmission coefficient , the calculation formula is For details, please refer to the following Table 1. The rotor vibration transmission coefficient of multiple test processes at multiple measuring points is mathematically averaged to obtain the final rotor vibration transmission coefficient , the calculation formula is .

[0027] Table 1 Calculation results of rotor vibration transmission coefficient

[0028] The above is only a specific embodiment of the present invention, and cannot be used to limit the scope of the invention. Therefore, the replacement of equivalent components, or equivalent changes and modifications made according to the scope of protection of the patent of the present invention, should still fall within the scope of this patent. In addition, the technical features of the present invention can be freely combined with each other, with each other, and with each other.

Claims

1. A method for designing rotor vibration transmission coefficient based on support dynamic strain test data, characterized in that: include: Step 1, perform deformation calculation of the supporting structure considering bolt connection; Step 2, calculating the deformation of the rigidly connected supporting structure; Step 3, obtaining the connection stiffness correction coefficient according to step 1 and step 2; Step 4: Obtain the average stress calculation result at the patch according to the connection stiffness correction coefficient; Step 5: According to the result of step 4, the average stress measurement result at the patch and the actual measured data of the external vibration of the engine are obtained; Step 6, obtaining the vibration load of the rotor support structure; Step 7: Calculate the rotor vibration transmission coefficient based on the vibration load of the rotor support structure.

2. The rotor vibration transmission coefficient design method based on support dynamic strain test data according to claim 1 is characterized in that: The step 1 is specifically as follows: Establish a finite element model of the supporting structure with bolted connections; A load is applied to the finite element model of the support structure with bolt connection to perform static strength calculation, thereby obtaining a first deformation result of the support structure and a first deformation amount S1 away from the load application position and the displacement constraint position.

3. The rotor vibration transmission coefficient design method based on support dynamic strain test data according to claim 2 is characterized in that: The step 2 is specifically as follows: Use rigid connection to replace bolt connection and establish finite element model of rigid connection supporting structure; Apply load to the finite element model of the rigidly connected support structure to perform static strength calculation, obtain the second deformation result of the support structure, and obtain the second deformation S2 away from the load application position and the displacement constraint position and the initial elastic modulus of the material at the rigid connection position .

4. The rotor vibration transmission coefficient design method based on support dynamic strain test data according to claim 3 is characterized in that: The step 3 is specifically as follows: Change the elastic modulus of the rigid connection position, apply the load and perform static strength iteration calculation until , obtain the material elastic modulus of the rigid connection position at this time ; By formula Get the connection stiffness correction factor .

5. The rotor vibration transmission coefficient design method based on support dynamic strain test data according to claim 4 is characterized in that: The step 4 is specifically as follows: Considering the connection stiffness correction coefficient, the elastic modulus of the material at the bolt connection position is corrected, and the rigid connection finite element model of the supporting structure at different support points is established; Apply the rotor lateral vibration load F to perform simulation calculations and obtain the stress distribution results of the supporting structure; According to the stress distribution results of the supporting structure, select the finite element nodes within the range of the strain gauge patch position grid; The average stress of the finite element node is used to calculate the average stress at the support structure patch. .

6. The rotor vibration transmission coefficient design method based on support dynamic strain test data according to claim 5 is characterized in that: The step 5 is specifically as follows: The actual vibration response data of the casing is measured by vibration test equipment ; By formula , get the average stress measurement result at the patch ,in, is the dynamic strain data of the support, and E is the mechanical property data of the material.

7. The rotor vibration transmission coefficient design method based on support dynamic strain test data according to claim 6 is characterized in that: The step 6 is specifically as follows: According to the formula , obtain the vibration load of the rotor support structure , where F is the rotor lateral vibration load.

8. The rotor vibration transmission coefficient design method based on support dynamic strain test data according to claim 7 is characterized in that: The step 6 is specifically as follows: By formula Get the single rotor vibration transmission coefficient ; By formula , and the final rotor vibration transmission coefficient is obtained .

Images