A stiffness matching design method for aero-engine casing static test

Abstract

The application provides an aero-engine casing static test rigidity matching design method, comprising the following steps: ① simulating and calculating the stress and deformation of the key positions of the casing under the engine state, and then calculating the strength reserve and rigidity of the key positions; ② designing a switching casing connected with the casing, simulating and calculating the stress and deformation of the casing under the test state, and correcting the test load according to the stress results of the key positions. The application can realize the rigidity matching design in the aero-engine casing design process, facilitate the rigidity matching research on the casing static test, and ensure that the strength reserve of the casing under the test state is consistent with the engine state through the stress correction, and the deformation of the casing is also consistent with the engine state through the rigidity matching.

Description

Technical Field

[0001] This invention relates to a static test stiffness matching design method for an aero-engine casing, belonging to the field of aero-engine power mechanism design technology. Background Technology

[0002] As a crucial component of the engine, the engine casing, along with other components, forms the airflow channel and is also a vital load-bearing and force-transmitting structure. The thrust generated by the engine is transmitted to the aircraft through mounting joints installed on the casing. For pressurized gas components, the intermediate casing and the outer bypass casing are the two most critical load-bearing and force-transmitting casings, and their static strength and stiffness directly affect the engine's proper functioning. During the engine design process, static stress tests on the casing are necessary to ensure that the engine casing meets strength requirements.

[0003] The engine casing connects to the preceding and following components on the engine, forming the engine's power transmission system. Therefore, the loads on the casing itself are extremely complex. The quality of the casing's structural design directly affects the engine's aerodynamic performance, safety, reliability, durability, and thrust-to-weight ratio. During engine development and use, examples of engine failures caused by the casing are common, such as cracking of the intermediate casing support plate or mounting edge. The strength design of casing components is crucial for ensuring the engine's normal operation and safety. In engine development, static strength of the casing is a fundamental requirement, necessitating static testing. However, static testing cannot fully simulate the constraints and stresses experienced by the casing under engine conditions. Therefore, static testing must be conducted according to the actual test conditions. For example, the intermediate casing is the most important load-bearing casing in the engine, with multiple mounting edges connecting to components such as the fan casing, compressor casing, outer bypass casing, bearing housing, and main mounting section. The loads transmitted from these components are transferred to the aircraft through the mounting sections on the intermediate casing. In engine mode, the intermediate casing mounting section is fixedly connected to the aircraft, with the other mounting edges transmitting loads. However, this constraint cannot be achieved under test conditions, necessitating a change in the constraint method. Typically, the load is applied to the other mounting edges and mounting sections by constraining the shunt ring mounting edge. Furthermore, since the components connected to the intermediate casing possess a certain rigidity, directly applying loads to the intermediate casing mounting edges would be inconsistent with actual conditions and could cause excessive casing deformation. Therefore, a transition casing needs to be designed to simulate the rigidity of the connected components during testing. Currently available standards and literature typically only define the length and thickness requirements of the transition casing, without addressing stiffness matching. Therefore, conducting stiffness matching research for static casing tests is essential. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method for stiffness matching design in static testing of an aero-engine casing. This method enables stiffness matching design during the aero-engine casing design process, facilitating stiffness matching studies in static testing of the casing.

[0005] The present invention is achieved through the following technical solutions.

[0006] This invention provides a static test stiffness matching design method for an aero-engine casing, comprising the following steps:

[0007] ① The stress and deformation of key parts of the computer box under engine conditions are simulated, and then the strength reserve and stiffness of key parts are calculated.

[0008] ② Design an adapter housing connected to the main housing, simulate the stress and deformation of the computer housing under test conditions, and correct the test load based on the stress results of key parts;

[0009] ③ After multiplying the initial load under test conditions by the load correction factor α, the deformation results of the key parts are calculated, and then the stiffness of the casing under test conditions is calculated.

[0010] ④ Analyze and compare the stiffness of key parts of the casing under engine condition and test condition. If the stiffness values ​​are consistent, proceed to the next step; otherwise, return to step ②.

[0011] ⑤ Iterative calculations show that the stress and deformation distribution of the casing under test conditions tend to be consistent with that of the engine.

[0012] Key components of the casing include the bearing housing and the mounting edge.

[0013] In step ②, the goal of the test load correction is to ensure that the strength reserve of the casing remains consistent.

[0014] In step ①, the strength reserve of the key components is calculated according to the following formula:

[0015]

[0016] In the formula, n1 represents the strength reserve of key components under engine conditions, and σ 1max σ0 represents the maximum stress in the critical component under engine conditions, and σ0 represents the allowable stress of the material in the critical component under engine conditions.

[0017] The stiffness of the critical components is calculated based on the deformation rate, which includes the deformation rate of the critical components under engine conditions and the rate of change of the torsional angle of the critical components under engine conditions. The deformation rate is calculated according to the following formula:

[0018]

[0019]

[0020] In the formula, k1 is the deformation rate of the key parts under engine conditions, and δ 1max θ0 represents the maximum deformation of the critical component under engine conditions, l0 represents the initial axial length of the casing under engine conditions, and θ1 represents the rate of change of the torsional angle of the critical component under engine conditions. This represents the maximum stress in critical components under engine conditions.

[0021] In step ④, when returning to step ②, the design parameters of the adapter box are adjusted.

[0022] The design parameters include the thickness and length of the adapter casing.

[0023] The design parameters also include the support plate depth and support plate width of the adapter casing.

[0024] In step ②, the stress of the casing under test conditions needs to be calculated, including bending stiffness, torsional stiffness and axial stiffness.

[0025] In step ②, the deformation of the casing under test conditions needs to be calculated, including radial deformation, torsional deformation and axial deformation.

[0026] The beneficial effects of this invention are as follows: it enables stiffness matching design in the design process of aero-engine casing, facilitating stiffness matching research in static tests of the casing; by simulating the stress and deformation of the casing under engine and test conditions, stress correction ensures that the strength reserve of the casing under test conditions is consistent with that under engine conditions, and at the same time, stiffness matching ensures that the deformation of the casing is also consistent with that under engine conditions. Attached Figure Description

[0027] Figure 1 This is a flowchart illustrating at least one embodiment of the present invention;

[0028] Figure 2 yes Figure 1 Installation diagram of the middle casing. Detailed Implementation

[0029] The technical solution of the present invention is further described below, but the scope of protection is not limited to what is described.

[0030] Example 1

[0031] like Figure 1 The method for static test stiffness matching design of an aero-engine casing, as shown, includes the following steps:

[0032] ① The stress and deformation of key parts of the computer box under engine conditions are simulated, and then the strength reserve and stiffness of key parts are calculated.

[0033] ② Design an adapter housing connected to the main housing, simulate the stress and deformation of the computer housing under test conditions, and correct the test load based on the stress results of key parts;

[0034] ③ After multiplying the initial load under test conditions by the load correction factor α, the deformation results of the key parts are calculated, and then the stiffness of the casing under test conditions is calculated.

[0035] ④ Analyze and compare the stiffness of key parts of the casing under engine condition and test condition. If the stiffness values ​​are consistent, proceed to the next step; otherwise, return to step ②.

[0036] ⑤ Iterative calculations show that the stress and deformation distribution of the casing under test conditions tend to be consistent with that of the engine.

[0037] Example 2

[0038] Based on Embodiment 1, the key components of the casing include the bearing housing and the mounting edge, such as... Figure 2 As shown.

[0039] Furthermore, in step ①, the strength reserve of key components is calculated according to the following formula:

[0040]

[0041] In the formula, n1 represents the strength reserve of key components under engine conditions, and σ 1max σ0 represents the maximum stress in the critical component under engine conditions, and σ0 represents the allowable stress of the material in the critical component under engine conditions.

[0042] Furthermore, the stiffness of critical components is calculated based on the deformation rate, which includes the deformation rate of critical components under engine conditions and the rate of change of torsional angle of critical components under engine conditions. The deformation rate is calculated according to the following formula:

[0043]

[0044]

[0045] In the formula, k1 is the deformation rate of the key parts under engine conditions, and δ 1max θ0 represents the maximum deformation of the critical component under engine conditions, l0 represents the initial axial length of the casing under engine conditions, and θ1 represents the rate of change of the torsional angle of the critical component under engine conditions. This represents the maximum stress in critical components under engine conditions.

[0046] Example 3

[0047] Based on Example 1, in step ②, the goal of performing test load correction is to ensure consistent casing strength reserves.

[0048] In step ②, the stress of the casing under test conditions needs to be calculated, including bending stiffness, torsional stiffness and axial stiffness.

[0049] In step ②, the deformation of the casing under test conditions needs to be calculated, including radial deformation, torsional deformation and axial deformation.

[0050] Example 4

[0051] Based on Example 1, in step ④, when returning to step ②, the design parameters of the adapter box are adjusted.

[0052] Design parameters include the thickness and length of the adapter casing.

[0053] The design parameters also include the depth and width of the adapter housing support plate.

[0054] Example 5

[0055] Based on the above embodiments, the specific steps are as follows:

[0056] 1. Simulate the stress and deformation of the computer housing under engine conditions to obtain the stress and deformation of key parts of the housing (bearing housing, mounting edge, etc.). Then, calculate the strength reserve and stiffness of the key parts based on the stress and deformation. The strength reserve and stiffness are calculated according to the following formula:

[0057]

[0058]

[0059]

[0060] In equation (1), n1 represents the strength reserve of key components under engine conditions, and σ 1max σ0 represents the maximum stress in the critical component under engine conditions, and σ1 represents the allowable stress of the material in the critical component under engine conditions; in equation (2), k1 represents the deformation rate of the critical component under engine conditions, and δ0 represents the allowable stress of the material in the critical component under engine conditions. 1max The maximum deformation of the key parts under engine conditions is given by θ1, and l0 is the initial axial length of the casing under engine conditions. In equation (3), θ1 is the rate of change of the torsional angle of the key parts under engine conditions. l0 represents the maximum stress in the critical parts under engine conditions, and l0 represents the initial axial length of the casing under engine conditions.

[0061] 2. A preliminary design of the adapter casing connected to the main casing was performed. The stress and deformation of the casing under test conditions were simulated. Test load corrections were made based on the stress results of key components to ensure consistent strength reserve of the casing. The strength reserve was calculated using the following formula:

[0062]

[0063] n1=αn2…………………………(5)

[0064] In equation (4), n2 is the strength reserve of key parts under engine conditions, and σ 2max σ0 represents the maximum stress in the critical part under engine conditions, and σ0 represents the allowable stress of the material in the critical part under engine conditions; in equation (5), α is the load correction factor.

[0065] 3. After multiplying the initial load under test conditions by the load correction factor α, calculate the deformation results of the key parts, and then calculate the stiffness of the casing under test conditions. The stiffness is calculated according to the following formula:

[0066]

[0067]

[0068] In equation (6), k2 is the deformation rate of the key parts under engine conditions, and δ 2max The maximum deformation of the key parts under engine conditions is given by θ2, and l0 is the initial axial length of the casing under engine conditions. In equation (7), θ2 is the rate of change of the torsional angle of the key parts under engine conditions. l0 represents the maximum stress in the critical parts under engine conditions, and l0 represents the initial axial length of the casing under engine conditions.

[0069] 4. Analyze and compare the stiffness of key parts of the casing under engine condition and test condition. If the stiffness values ​​are inconsistent, the design parameters such as the thickness and length of the adapter casing need to be adjusted, and then stress and deformation analysis should be carried out again.

[0070] 5. Through iterative calculation, the stress and deformation distribution of the casing under test conditions are found to be consistent with those of the engine under test conditions, and the error is within the acceptable range for engineering, i.e., k1 = k2 and θ1 = θ2.

Claims

1. A method for designing the stiffness matching of aero-engine casing in static testing, characterized in that: Includes the following steps: ① The stress and deformation of key parts of the computer box under engine conditions are simulated, and then the strength reserve and stiffness of key parts are calculated. ② Design an adapter housing connected to the main housing, simulate the stress and deformation of the computer housing under test conditions, and correct the test load based on the stress results of key parts; ③ Multiply the initial load under test conditions by the load correction factor. Then, the deformation results of the key parts are calculated, and then the stiffness of the casing under test conditions is calculated. ④ Analyze and compare the stiffness of key parts of the casing under engine condition and test condition. If the stiffness values ​​are consistent, proceed to the next step; otherwise, return to step ②. ⑤ Iterative calculations show that the stress and deformation distribution of the casing under test conditions tend to be consistent with that of the engine. The key components of the casing include the bearing housing and the mounting edge; in step ②, the goal of the test load correction is to ensure consistent casing strength reserves; in step ④, when returning to step ②, the design parameters of the adapter casing are adjusted. In step ①, the strength reserve of the key components is calculated according to the following formula: In the formula, This provides strength reserves for critical components in engine mode. This represents the maximum stress in critical components under engine conditions. This refers to the allowable stress of materials in key components under engine conditions. The stiffness of the critical components is calculated based on the deformation rate, which includes the deformation rate of the critical components under engine conditions and the rate of change of the torsional angle of the critical components under engine conditions. The deformation rate is calculated according to the following formula: In the formula, This represents the deformation rate of key components under engine conditions. This represents the maximum deformation of key components when the engine is in operation. This represents the initial axial length of the casing in engine mode. This represents the rate of change of torsional angle at key components under engine conditions. This represents the maximum stress in critical components under engine conditions.

2. The static test stiffness matching design method for aero-engine casing as described in claim 1, characterized in that: The design parameters include the thickness and length of the adapter casing.

3. The static test stiffness matching design method for aero-engine casing as described in claim 2, characterized in that: The design parameters also include the support plate depth and support plate width of the adapter casing.

4. The static test stiffness matching design method for aero-engine casing as described in claim 1, characterized in that: In step ②, the deformation of the casing under test conditions needs to be calculated, including radial deformation, torsional deformation and axial deformation.

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