Mechanical test frame for simulating fretting fatigue of tenon connection structure of aero-engine

Abstract

The invention discloses a mechanical test frame for simulating fretting fatigue of a tenon connection structure of an aero-engine, and belongs to the field of fretting fatigue tests. The channel specifically comprises a longitudinal main channel and a transverse auxiliary channel. The transverse beam, the stand column and the base achieve fixation of a longitudinal structure of the testing machine, the vertical actuating cylinder is a main load loading channel, and the transverse beam moves up and down to drive the vertical actuating cylinder to move longitudinally. The upper portion of the base is connected with the left supporting frame and the right supporting frame through sliding rails, the two horizontal actuating cylinders are fixed to the left supporting frame and the right supporting frame respectively and serve as secondary load loading channels, the left supporting frame and the right supporting frame are driven by the sliding rails to move face to face or relative to each other, and therefore the two horizontal actuating cylinders are driven to be combined or opened. The vertical actuating cylinder and the horizontal actuating cylinder adopt independent hydraulic controllers, so that respective adjustment of a longitudinal space and a transverse space is realized, and the fretting fatigue test requirements of test pieces with different sizes and shapes are met. Meanwhile, the test frame is simple in structure, reliable in rigidity and convenient to debug.

Description

Technical Field

[0001] The present invention belongs to the field of fretting fatigue tests, and particularly relates to a mechanical test frame for simulating the fretting fatigue of a tenon connection structure of an aero-engine. Background Art

[0002] In modern aero-engines, tenon connection structures are widely used to tightly connect blades and disks. Due to the operation of these key components in a high-stress and high-speed rotation environment, with minute relative motion and contact stress concentration, the tenon connection structure is extremely prone to fretting fatigue.

[0003] Fretting fatigue refers to fatigue damage caused by surface friction slip under small-amplitude vibration or contact friction conditions. This phenomenon not only causes local wear of materials but also induces the initiation and propagation of cracks, ultimately possibly leading to the failure of the tenon connection structure, seriously threatening the safety and reliability of the engine.

[0004] Existing fatigue test methods are difficult to accurately capture and control the complex stress state and fretting behavior of structures. Fretting fatigue is affected by the combined action of multiple factors, such as contact pressure, relative slip amplitude, frequency, temperature, and load spectrum, etc.

[0005] Therefore, a single test method often cannot comprehensively reflect the fretting fatigue characteristics of structures. In order to better simulate the fretting fatigue behavior of structures, it is necessary to design a special mechanical test frame, so as to facilitate the adjustment of fretting test conditions, accurately control the contact pressure and cyclic load, and be convenient for observing and recording the test state. Summary of the Invention

[0006] In view of the above problems, the present invention proposes a mechanical test frame for simulating the fretting fatigue of a tenon connection structure of an aero-engine, to study the fretting fatigue of mechanical structures in a laboratory environment. Through a bidirectional orthogonally adjustable actuator cylinder, external load is applied in two directions, namely the horizontal and vertical directions, so as to carry out experimental research on the fretting fatigue of components.

[0007] The mechanical test frame for simulating the fretting fatigue of a tenon connection structure of an aero-engine includes a longitudinal main channel and a transverse auxiliary channel; the longitudinal main channel includes: a cross beam, columns, a base, and a vertical actuator cylinder; the transverse auxiliary channel includes: a support frame, a stable bridge frame, a limit frame, and a horizontal actuator cylinder.

[0008] The cross beam, columns, and base realize the fixation of the longitudinal structure of the testing machine. The two columns are symmetrically and vertically fixed on the base, and the cross beam is placed on the top of the columns. A vertical actuator cylinder is vertically built in the middle of the cross beam. The vertical actuator cylinder is the main load loading channel, and the longitudinal movement of the vertical actuator cylinder is driven by the up and down movement of the cross beam;

[0009] Above the base, it is connected to the bottom of the support frame through a slide rail. There are two symmetrical left and right support frames, which are respectively parallel to the planes of the two columns. Two horizontal actuating cylinders are fixed on the left and right support frames on the opposite side, serving as the secondary load loading channels. The left and right support frames are driven to move towards / away from each other through the slide rail, thereby driving the two horizontal actuating cylinders to merge or open.

[0010] Openings are reserved at the top of the support frame for passing through the stable bridge. The stable bridge fits against the left and right sides of the horizontal actuating cylinder respectively. One end of the stable bridge is fixed to the left / right support frame, and the other end can be adjusted according to the lateral distance between the right / left support frames; a vertical building limit frame is fixed above the stable bridge, which fits against the top of the horizontal actuating cylinder. The limit frame combines the two stable bridges to restrict the horizontal actuating cylinder and prevent the follow-up deformation of the horizontal actuating cylinder in the vertical and front-back directions during the test.

[0011] The vertical actuating cylinder and the horizontal actuating cylinder adopt independent hydraulic controllers, and the size, frequency, displacement amplitude, etc. of the cyclic load are all independently controlled and adjusted; the longitudinal space and the lateral space are respectively adjusted, meeting the micro-motion fatigue test requirements of test pieces with different sizes and shapes.

[0012] Furthermore, the mechanical test frame of the present invention realizes the composite loading of longitudinal and transverse orthogonal loads, and the loads in the two directions are independently controlled without interference.

[0013] For the mechanical test frame of the present invention, the longitudinal space adjustment can be achieved by longitudinally adjusting the position of the cross beam or adding adjustment pads at the bottom of the support frame.

[0014] The advantages of the present invention are as follows:

[0015] 1. The mechanical test frame for simulating the micro-motion fatigue of the tenon connection structure of an aero-engine of the present invention considers the orthogonal load loading scheme, designs the vertical actuating cylinder and the horizontal actuating cylinder, and realizes the load loading and control in two directions;

[0016] 2. The mechanical test frame for simulating the micro-motion fatigue of the tenon connection structure of an aero-engine of the present invention has a simple structure, reliable stiffness, and is convenient for debugging;

[0017] 3. The mechanical test frame for simulating the micro-motion fatigue of the tenon connection structure of an aero-engine of the present invention has sufficient lateral and longitudinal spaces and adjustable positions of the actuating cylinders, meeting the micro-motion fatigue test requirements of different sizes and shapes. Description of the Drawings

[0018] Figure 1 a shows the force condition of a typical tenon connection structure under actual working conditions in the prior art.

[0019] Figure 1b is the external force load requirement of the micro-motion fatigue test piece for the mortise connection structure in the prior art.

[0020] Figure 2 This is a schematic diagram of the micro-motion fatigue mechanical test frame of the present invention.

[0021] Figure 3 This is a schematic diagram of the setting, installation and fixation scheme of the horizontal actuator cylinder of the present invention.

[0022] Figure 4 a is the longitudinal adjustment schematic diagram of the micro-motion fatigue test frame of the present invention.

[0023] Figure 4 b is the transverse adjustment schematic diagram of the micro-motion fatigue test frame of the present invention.

[0024] Figure 5 This is the application of the micro-motion fatigue test frame in various tests. Detailed implementation manners

[0025] The present invention will be further described in detail below with reference to the accompanying drawings.

[0026] A mechanical test frame for simulating the micro-motion fatigue of the mortise connection structure of an aero-engine according to the present invention can realize orthogonal load loading, and more conveniently and adjustably carry out micro-motion fatigue tests on test pieces such as mortise connection structures and indenter-plate structures;

[0027] As Figure 2 shown, it includes a longitudinal main channel and a transverse auxiliary channel; the longitudinal main channel includes: a cross beam, columns, a base and a vertical actuator cylinder; the transverse auxiliary channel includes: a support frame, a stable bridge, a limit frame and a horizontal actuator cylinder.

[0028] The cross beam, columns and base are similar to those of a traditional mechanical fatigue testing machine, and their main function is to fix the longitudinal structure of the testing machine; the vertical actuator cylinder is the main load loading channel, and the upper limit of the lateral loading force needs to be at least greater than 5000 N; the upper limit of the longitudinal main tensile force needs to be at least greater than 80000 N in the force output range and the corresponding displacement output range to realize the loading of the main longitudinal load of the component;

[0029] The two columns are symmetrically and vertically fixed on the base, the cross beam is erected on the top of the columns, and the vertical actuator cylinder is vertically erected in the middle of the cross beam. The vertical actuator cylinder is the main load loading channel, and the longitudinal movement of the vertical actuator cylinder is driven by the up and down movement of the cross beam;

[0030] The support frames are two symmetrical left and right ones, respectively parallel to the plane of the two columns, playing a role in supporting the equipment of the transverse auxiliary channel, and are connected to the base through slide rails at the bottom, and the lateral distance can be adjusted to meet the test requirements of test pieces of different sizes;

[0031] Two horizontal actuating cylinders are fixed on the left and right support frames on the opposite side, serving as the secondary load loading channels, with a force output range of 0 - 10,000 N and a corresponding displacement output range, to achieve the loading of the lateral load of the component. The left and right support frames are driven by the slide rail to move towards / opposite to each other, thereby driving the two horizontal actuating cylinders to merge or open.

[0032] Openings are reserved at the top of the support frame for passing through the stable bridge frame. The stable bridge frame fits against the left and right sides of the horizontal actuating cylinder respectively. One end of the stable bridge frame is fixed to the left / right support frame, and the other end can be adjusted according to the lateral distance between the right / left support frames; A vertical erection limit frame is fixed above the stable bridge frame, which fits against the top of the horizontal actuating cylinder. The limit frame combines the two stable bridge frames to restrict the horizontal actuating cylinder and prevent the follow-up deformation of the horizontal actuating cylinder in the vertical direction and the front-back direction during the test.

[0033] The vertical actuating cylinder and the horizontal actuating cylinder adopt independent hydraulic controllers, and the magnitude, frequency, displacement amplitude, etc. of the cyclic load are all independently controlled and adjusted; Based on this, the fretting fatigue tests with different load ratios and loading methods can be designed to further explore the influencing factors of fretting fatigue.

[0034] Furthermore, the mechanical test frame of the present invention not only realizes the separate adjustment of the longitudinal space and the lateral space, meeting the requirements of the fretting fatigue test for test pieces of different sizes and shapes. Moreover, it can also realize the composite loading of the longitudinal and lateral orthogonal loads, and the loads in the two directions are independently controlled and do not interfere with each other.

[0035] For the mechanical test frame of the present invention, the adjustment of the longitudinal space can be achieved by longitudinally adjusting the position of the cross beam or adding adjustment pads at the bottom of the support frame.

[0036] The so-called fretting refers to the small relative sliding generated between multiple components during the external force loading process. The fatigue failure life caused by fretting will be much smaller than the conventional fatigue life;

[0037] The fretting fatigue test carried out by the present invention in the laboratory environment designs a bridge-type flat fretting fatigue structure, and creates the fretting phenomenon in the contact area through the tight contact between the bridge-type indenter and the flat test; The specific process is as follows:

[0038] First, the flat specimen is connected and fixed to the vertical actuating cylinder through a fixture, and the two bridge-type indenters are respectively connected and fixed to the two horizontal actuating cylinders through fixtures;

[0039] Then, move the vertical actuating cylinder to lower the center of the flat specimen to the horizontal connection line of the two bridge-type indenters; And apply a lateral force to the preset load magnitude of the test plan to complete the tight fit between the bridge-type indenter and the flat specimen;

[0040] Next, according to the test plan, apply cyclic force loads to the vertical channel until the test piece undergoes fatigue fracture; record the fretting fatigue test life and remove and save the specimen after fracture.

[0041] By replacing with a new flat specimen or adjusting the magnitude of the applied lateral force, conduct the experiment again and record and save the results.

[0042] Example 1: Fretting fatigue test of a simulated tenon joint structure

[0043] As Figure 1 shown in a, it is a schematic diagram of the radial and circumferential stress distributions of a disk under the actual working conditions of an aeroengine; for a single tenon joint structure, the blade generates a centrifugal force due to rotation, and the disk simultaneously bears the radial centrifugal force and the circumferential tensile stress. As Figure 1 shown in b, it is a simplified designed simulated tenon joint structure, which can be used to conduct fretting fatigue tests in a laboratory environment. Apply an external force load F longitudinally a to simulate the radial force received by the tenon joint structure, and apply an external force load F transversely t to simulate the circumferential force received by the tenon joint structure.

[0044] As Figure 2 shown, it is the mechanical framework of the fretting fatigue test proposed by the present invention that is applicable to the above-mentioned bidirectional loading requirements. Among them, 1 is the crossbeam, 2 is the column, 3 is the limit frame, 4 is the stable bridge frame, 5 is the support frame, 6 is the base, 7 is the vertical actuator cylinder, and 8 is the horizontal actuator cylinder.

[0045] Specifically, a limit frame is provided on the horizontal actuator cylinder, and the limit frame is connected to the support frame through the stable bridge frame, as Figure 3 shown. Due to the close contact between components, sticky slip may occur between the test pieces during the test, which may affect the position of the horizontal actuator cylinder. The main purpose of the limit frame is to limit the follow-up deformation of the horizontal actuator cylinder during longitudinal loading.

[0046] Furthermore, according to the fretting fatigue test framework proposed by the present invention, composite loading of longitudinal and transverse orthogonal loads can be achieved, and the loads in the two directions are independently controlled and do not interfere with each other. For example, keep the longitudinal load unchanged and change the magnitude of the transverse load to study the variation law of the fatigue life.

[0047] Furthermore, according to the fretting fatigue test framework proposed by the present invention, separate adjustment of the longitudinal space and the transverse space can be achieved. As Figure 4 shown in a, it is a schematic diagram of the longitudinal adjustment of the fretting fatigue test framework. The longitudinal space adjustment can be achieved by longitudinally adjusting the position of the crossbeam or adding adjustment pads at the bottom of the support frame. As Figure 4As shown in Fig. b, it is a schematic diagram of the lateral adjustment of the fretting fatigue test frame. The bottom of the support frame is connected to the base through a slide rail, and the position of the support frame can be adjusted and changed, so as to achieve lateral space adjustment. Based on the design proposed in the present invention, the proposed fretting fatigue test frame has sufficient degrees of freedom in space and can meet the requirements of fretting fatigue tests with different sizes and shapes.

[0048] Furthermore, the fretting fatigue test frame proposed in the present invention has reliable stiffness and a simple structure. There is sufficient space outside the test frame, and equipment such as sensors and recorders required in the test can be built separately, which is convenient for real-time monitoring and data recording during the test process.

[0049] As Figure 5 shown, it is the extended application of the fretting fatigue test frame in various tests. In addition to the fretting fatigue test of the mortise connection structure mentioned in Embodiment 1, the fretting fatigue basic test and the orthogonal cross multi-axis test can also be carried out. The test frame proposed in the present invention has the characteristics of bidirectional orthogonal independent loading, and a suitable cross test piece can be designed for multi-axis fatigue test. The four ends of the cross test piece are respectively fixed on the vertical actuator cylinder and the horizontal actuator cylinder, and different longitudinal loads and lateral loads, such as tension and torsion, are given through the console to explore the multi-axis fatigue characteristics and failure behaviors of the component.

[0050] In summary, the present invention provides a design of a mechanical frame for fretting fatigue test carried out in a laboratory environment, considering orthogonal loading, introducing a horizontal actuator cylinder, and realizing independent adjustment and control of bidirectional loads. At the same time, the test system has a simple structure, reliable stiffness, convenient debugging, and has good application significance and test value.

Claims

1. A mechanical test framework for simulating fretting fatigue of a tenon connection structure of an aero-engine, characterized in that It includes a longitudinal main channel and a transverse auxiliary channel; The longitudinal main channel includes: cross beams, columns, pedestals, and vertical actuating cylinders; the transverse auxiliary channel includes: support frames, stable bridge frames, limit frames, and horizontal actuating cylinders; The columns are fixed on the pedestals, and cross beams are mounted on the tops. A vertical actuating cylinder is vertically built in the middle of the cross beam. The vertical actuating cylinder is the main load loading channel, and the longitudinal movement of the vertical actuating cylinder is driven by the up and down movement of the cross beam; Above the pedestal, it is connected to the bottom of the support frame through a slide rail. There are two symmetrical left and right support frames, and each fixes a horizontal actuating cylinder respectively, which is the secondary load loading channel. The left and right support frames are driven to move towards / opposite each other through the slide rail, so as to drive the two horizontal actuating cylinders to merge or open.

2. The mechanical test frame for simulating fretting fatigue of a tenon connection structure of an aero-engine as claimed in claim 1, wherein, The said support frames are respectively parallel to the planes of the two columns.

3. A mechanical test frame for simulating fretting fatigue of a tenon connection structure of an aero-engine, as claimed in claim 1, wherein Openings are reserved at the tops of the said support frames for passing through the stable bridge frames. The stable bridge frames are respectively attached to the left and right sides of the horizontal actuating cylinders. A limit frame is vertically fixed above the stable bridge frames and is attached to the top of the horizontal actuating cylinder. The limit frame combines the two stable bridge frames to limit the horizontal actuating cylinder and prevent the follow-up deformation of the horizontal actuating cylinder in the vertical direction and the front and back directions during the test.

4. A mechanical test frame for simulating fretting fatigue of a tenon connection structure of an aero-engine as described in claim 3, characterized in that One end of the said stable bridge frame is fixed to the left / right support frame, and the other end can be adjusted according to the transverse distance between the right / left support frames.

5. A mechanical test frame for simulating fretting fatigue of a tenon connection structure of an aero-engine, as claimed in claim 1, wherein The said vertical actuating cylinder and horizontal actuating cylinder adopt independent hydraulic controllers, and the magnitude, frequency, and displacement amplitude of the cyclic load are independently controlled and adjusted; the separate adjustment of the longitudinal space and the transverse space is realized, meeting the requirements of the fretting fatigue test for test pieces of different sizes and shapes.

6. A mechanical test frame for simulating fretting fatigue of a tenon connection structure of an aero-engine, as described in any one of claims 1-5, characterized in that The said mechanical test frame realizes the composite loading of longitudinal and transverse orthogonal loads, and the loads in the two directions are independently controlled and do not interfere with each other.

7. A mechanical test frame for simulating fretting fatigue of a tenon connection structure of an aero-engine, as described in any one of claims 1-5, characterized in that For the said mechanical test frame, the adjustment of the longitudinal space is realized by longitudinally adjusting the position of the cross beam or adding adjustment pads at the bottom of the support frame.

8. A mechanical test frame for simulating fretting fatigue of a tenon connection structure of an aero-engine, as claimed in claim 1, wherein Sensors and recorder devices required in the test are separately built outside the test frame to facilitate the real-time monitoring and data recording during the test process.

9. A mechanical test frame for simulating fretting fatigue of a tenon connection structure of an aero-engine, as claimed in claim 1, wherein, The said mechanical test frame has the characteristics of bidirectional orthogonal independent loading, and a multi-axis fatigue test is carried out by designing a suitable cross test piece.

10. A mechanical test frame for simulating fretting fatigue of a tenon connection structure of an aero-engine, as claimed in claim 9, wherein The four ends of the cross test piece are respectively fixed on the vertical actuating cylinder and the horizontal actuating cylinder, and different longitudinal loads and transverse loads are given through the console to explore the multi-axis fatigue characteristics and failure behaviors of the component.

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