Fatigue performance testing device

Abstract

The application relates to the technical field of fatigue test, and discloses a fatigue performance test device which comprises a supporting table, a mounting seat, a rotor, an exciting unit and a to-be-tested piece. The mounting seat is arranged on the supporting table, the mounting seat is provided with a mounting through hole, and the mounting through hole extends along a first direction. The rotor is coaxially arranged in the mounting through hole and at least partially located in the mounting through hole. The exciting unit is connected to and supported at two ends of the rotor, and the exciting unit is suitable for forming an exciting force field at the two ends of the rotor. The to-be-tested piece is sleeved on the rotor and located in the mounting through hole. The to-be-tested piece is provided with a first boss located in an inner ring and a second boss located in an outer ring. The exciting force field is applied to the to-be-tested piece through the rotor. Thus, the mechanical transmission process in an actual engine is restored.

Description

Technical Field

[0001] This invention relates to the field of structural fatigue testing technology, and more specifically to a fatigue performance testing device. Background Technology

[0002] Elastic support structures are typically used in aero-engine rotor systems to improve bearing performance and reduce engine vibration. High speed, high power-to-weight ratio, high power, high load, and flexible rotors are key characteristics of small and medium-sized aero-engines. The use of elastic support structures in rotor systems can suppress rotor vibration through support deformation and the internal damping effect of the material. Furthermore, when the engine rapidly passes through the critical speed, the elastic support squeezes the oil film damper to limit the vibration amplitude of the rotor beyond the critical speed. However, during engine engineering development, it was found that elastic supports exhibit significant stress concentration and may exceed their load-bearing limits during rotor load transmission, leading to fatigue damage, fatigue cracks, or even fatigue fracture. Therefore, it is necessary to obtain the fatigue performance of the elastic support structure during the product development phase to evaluate whether the elastic support structure meets the strength requirements of the product design.

[0003] The existing testing methods simulate rotor force paths that are completely opposite to the actual force transmission paths of the engine. This makes it impossible to accurately reproduce the real working conditions where the rotor excitation force field directly acts on the test piece. Consequently, it affects the accuracy of obtaining the key parameters required for evaluating fatigue performance in real time during the test, resulting in a large deviation between the test results and the actual operating conditions of the engine. This makes it impossible to effectively verify the fatigue strength of the steel ring elastic support structure. Summary of the Invention

[0004] This invention provides a fatigue performance testing device to solve the above-mentioned technical problems.

[0005] This invention provides a fatigue performance testing device, comprising: Support platform; Mounting base, the mounting base is disposed on the support platform, the mounting base has a mounting through hole, the mounting through hole extends along a first direction; A rotor, which coaxially passes through the mounting through hole and is at least partially located within the mounting through hole; A vibration excitation unit is connected to and supported at both ends of the rotor, and the vibration excitation unit is adapted to generate a vibration force field at both ends of the rotor; The test piece is sleeved on the rotor and located in the mounting through hole. The test piece has a first boss located on its inner ring and a second boss located on its outer ring. The excitation force field is applied to the test piece through the rotor.

[0006] Beneficial effects: Therefore, by applying forces synchronously at both ends of the rotor through the excitation unit, a combined excitation force field is generated. This force field first acts on the rotor, and then the rotor acts as the main force-applying body, transmitting the force sequentially from the inside to the outside to the first boss of the inner ring and the second boss of the outer ring of the test piece. Finally, it is supported by the reaction force of the mounting seat. This restores the mechanical transmission process in the actual engine, so that the deformation trend, stress concentration location and stress state of the test piece during the test process are highly consistent with the actual working state of the engine.

[0007] In one alternative embodiment, the rotor has a first end and a second end, and the excitation unit includes a first exciter and a second exciter. The first exciter is adapted to apply an excitation force along a first axial direction to the first end and the second end, and the second exciter is adapted to apply an excitation force along a second axial direction to the first end and the second end. Both the first axial direction and the second axial direction are perpendicular to the first direction, and the first axial direction and the second axial direction are perpendicular.

[0008] Beneficial effects: Therefore, the above structure enables the input of dynamic excitation loads with independently adjustable initial phase, amplitude, and frequency to both ends of the rotor in two mutually perpendicular dimensions. By vector synthesis of the excitation force fields applied to both ends of the shaft by the first and second exciters, the motion trajectory of the rotor's center of mass can be controlled, thereby faithfully reproducing the dynamic characteristics of the aero-engine rotor system during actual operation under test conditions.

[0009] In one alternative implementation, the first exciter has a first vibration period, and the second exciter has a second vibration period, wherein the first vibration period and the second vibration period are the same.

[0010] Beneficial effects: Therefore, the above settings ensure that the excitation forces in the two orthogonal directions maintain a high degree of synchronization and frequency consistency in the time dimension, thus providing the necessary time and frequency basis for synthesizing a stable and continuous excitation force field on the rotor.

[0011] In one alternative embodiment, the first exciter has a first amplitude and a first initial phase, and the second exciter has a second amplitude and a second initial phase, wherein the first amplitude and the second amplitude are equal, and the first initial phase and the second initial phase differ by 90°.

[0012] Beneficial effects: Therefore, the composite trajectory of the rotor's center of mass can be a circle.

[0013] In one optional embodiment, the test piece includes a limiting structure that engages with the mounting base to limit the rotation of the test piece relative to the mounting base.

[0014] Beneficial effects: Therefore, the present invention restricts the rotation of the test piece relative to the mounting base, ensuring that the circumferential position of the test piece remains stable during the process of being subjected to high-frequency excitation load, and effectively preventing unexpected rotation or position drift of the test piece due to vibration torque or inertia.

[0015] In one optional embodiment, the fatigue performance testing device includes strain gauges, and along the circumference of the test piece, there are bonding positions with the minimum stress gradient between adjacent external protrusions. The strain gauges are bonded at any bonding position, and the strain gauges are suitable for feeding back the stress at the bonding position.

[0016] Beneficial effects: Therefore, the strain gauge can collect and record the local stress state of its area under the action of a dynamic rotating excitation field in real time, and calculate the limit stress level at the maximum stress position of the test piece through a pre-set sensitivity coefficient, thereby evaluating the fatigue life and performance indicators of the test piece.

[0017] In one optional embodiment, the inner side of the mounting through hole is provided with a recess, the strain gauge is located radially between the recess and the test piece, and the strain gauge has a lead terminal connected to a cable. The fatigue performance testing device further includes a receiving unit, which is electrically connected to the lead terminal via the cable.

[0018] Beneficial effects: Therefore, by specifically designing a cable outlet recess (notch) on the mounting base, sufficient radial clearance and cable outlet space are provided for the strain gauge, adhesive layer and lead terminals with a certain thickness, so that the strain gauge can be placed between the test piece and the mounting base.

[0019] In one optional embodiment, the excitation unit includes a first exciter and a second exciter, and the excitation unit further includes a first force transmission structure and a second force transmission structure, wherein the first force transmission structure extends along a first axial direction, the second force transmission structure extends along a second axial direction, and the first axial direction and the second axial direction are perpendicular to each other. The first force transmission structure has a first connecting end and a second connecting end, which are respectively connected to the two ends of the rotor; the second force transmission structure has a third connecting end and a fourth connecting end, which are respectively connected to the two ends of the rotor.

[0020] Beneficial effects: Therefore, the present invention can achieve the same excitation force applied to both ends of the excitation rotor by a single exciter, thereby effectively avoiding rotor axial deviation, warping or additional bending moment that may be caused by single-end loading, and ensuring that the rotor can maintain perfect spatial parallel movement or controlled orbital motion when subjected to high-frequency excitation.

[0021] In one optional embodiment, the fatigue performance testing device further includes a first detection unit, the measurement unit being adapted to measure the excitation displacement at both ends of the rotor.

[0022] Beneficial effects: The first detection unit can directly detect the dynamic displacement of the fixed base, thereby accurately characterizing the macroscopic displacement trajectory of the rotor, and then reflecting the excitation load level applied by the exciter to the test piece through displacement data.

[0023] In one optional embodiment, the fatigue performance testing device further includes a second detection unit adapted to measure the acceleration at both ends of the rotor.

[0024] Beneficial effects: Therefore, the displacement at the fixed seat obtained by acceleration integration can accurately and realistically reflect the true macroscopic displacement of the rotor as a whole in the corresponding excitation direction, thus providing richer dynamic data support for comprehensively evaluating the stress and deformation of the test piece under complex dynamic force field. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a front view of a fatigue performance testing device according to an embodiment of the present invention; Figure 2 for Figure 1 Top view of the fatigue performance testing device shown; Figure 3 This is a top-view perspective view of a fatigue performance testing device according to an embodiment of the present invention; Figure 4 This is a partial cross-sectional schematic diagram of a fatigue performance testing device according to an embodiment of the present invention; Figure 5 for Figure 4 A schematic diagram of the three-dimensional structure; Figure 6 This is a schematic diagram of the structure of the part under test; Figure 7 This is a side view of the part to be tested; Figure 8 This is a schematic diagram of the mating structure of the part under test; Figure 9 This is a top-view, partially enlarged, three-dimensional schematic diagram of a fatigue performance testing device according to an embodiment of the present invention; Figure 10 This is a schematic diagram of a positioning bushing structure applied in a fatigue performance testing device according to an embodiment of the present invention; Figure 11 Force analysis and stress distribution diagram of the test piece; Figure 12 A diagram simulating the rotor excitation force signal; Figure 13 A diagram simulating rotor acceleration signals; Figure 14 The composite image of the motion trajectory of the rotor's geometric center.

[0027] Explanation of reference numerals in the attached figures: 100. Support platform; 110. Annular structure; 120. Adapter seat; 121. Annular fixing protrusion; 130. Support frame; 200, Mounting base; 210, Mounting through hole; 220, Limiting groove; 230, Extension; 240, Retaining ring; 250, Annular limiting protrusion; 300, Rotor; 310, First end; 320, Second end; 330, Force transmission boss; 400, Vibration unit; 410, First vibrator; 420, Second vibrator; 430, First force transmission structure; 431, First connecting end; 432, Second connecting end; 440, Second force transmission structure; 441, Third connecting end; 442, Fourth connecting end; 450, Fixing base; 460, Vibration control system; 500, Part to be tested; 510, First boss; 520, Second boss; 530, Limiting boss; 600, strain gauge; 700, Positioning bushing. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] As can be seen from the above, existing fatigue testing technologies for elastic support structures of aero-engines generally suffer from a fundamental mechanical defect: current testing devices typically use external excitation equipment to directly apply excitation loads to the outermost support ring. In this traditional loading mode, the external excitation force is first forcibly applied to the outer structure of the elastic ring, and then forced to be transmitted to the inner structure, forming a force transmission path "from the outside to the inside".

[0030] However, in real-world aero-engine operation, centrifugal force and alternating vibration loads originate from the high-speed rotating rotor system inside. These loads are transmitted sequentially from the internal rotor to the outer bearings, elastic rings, and finally to the external casing or bearing housing. Therefore, the actual force transmission process is necessarily "from the inside out." Consequently, because the "from the outside in" force application method in related technologies is completely opposite to the actual "from the inside out" force transmission path of a real engine, this inevitably leads to severe distortion of the stress point, deformation trend, and overall stress distribution of the elastic ring during testing. This makes it impossible to accurately reproduce the stress state under real-world conditions, resulting in significant deviations in the final fatigue life assessment data.

[0031] Therefore, for reference Figures 1 to 10 The fatigue performance testing device shown includes a support platform 100, a mounting base 200, a rotor 300, a vibration unit 400, and a test piece 500. The mounting base 200 is mounted on the support platform 100.

[0032] Among them, attention Figure 1 and Figure 2 The support platform 100 serves as the mounting base for the entire testing device, providing stable load-bearing capacity and ensuring the overall structural rigidity. The mounting base 200 is disposed on the support platform 100, as shown in the reference... Figure 3 As shown in Figure 4, the mounting base 200 has a mounting through hole 210 extending in the first direction to provide an outer ring assembly positioning surface and radial constraint for the test piece 500, thereby simulating the bearing housing structure of a real aero-engine.

[0033] Among them, reference Figure 2 and Figure 4 The rotor 300 is coaxially inserted into the mounting through hole 210 and is at least partially located within the mounting through hole 210. The rotor 300 serves as the internal force transmission core in the experiment, effectively simulating the rotor system under the actual operating conditions of an engine. The excitation unit 400 is connected to and supported at both ends of the rotor 300, and is suitable for forming an excitation force field at both ends of the rotor 300 to simulate the dynamic excitation force field conditions of an engine operating at high speed.

[0034] Among them, reference Figure 4 and Figure 5 The test piece 500 is sleeved on the rotor 300 and located within the mounting through hole 210, combined with... Figure 6 The test piece 500 has a first boss 510 located on its inner ring and a second boss 520 located on its outer ring, thus having a structure similar to the elastic annular ring on an engine. (Reference) Figures 3 to 5 The excitation force field is directly applied to the test piece 500 through the rotor 300, so that the external load can be accurately introduced from the rotor 300 to the inner ring first boss 510 of the test piece 500, and then transmitted outward to the mounting base 200 through the outer ring second boss 520. This ensures that the test piece 500 is subjected to fatigue testing in a simulated real assembly constraint and stress environment, thereby constructing a rotation path "from the inside out".

[0035] Therefore, in this embodiment, the excitation unit 400 synchronously applies forces to both ends of the rotor 300 to synthesize an excitation force field. This force field first acts on the rotor 300, and then the rotor 300 acts as the main force-applying body, transmitting the force from the inside to the outside to the inner ring first boss 510 and outer ring second boss 520 of the test piece 500. Finally, it is supported by the reaction force of the mounting seat 200, thereby restoring the mechanical transmission process in the actual engine, so that the deformation trend, stress concentration location and stress state of the test piece 500 during the test process are highly consistent with the actual working state of the engine.

[0036] Therefore, the fatigue performance testing device provided in this embodiment constructs a testing system that transmits rotational excitation force from the inside out through a support platform 100, a mounting base 200, a rotor 300, two-end excitation units 400, and a test piece 500 with an inner and outer double boss structure. This fundamentally solves the technical problems of reversed force transmission paths and distorted force deformation in existing test methods, making the fatigue parameters obtained in real time during the test more realistic and effective. It significantly improves the accuracy, reliability, and engineering application value of high-cycle fatigue strength verification and life assessment of steel ring elastic support structures.

[0037] In this embodiment, a clearance fit can be used between the test piece 500 and the rotor 300, while a transition fit can be used between the test piece 500 and the mounting base 200. Furthermore, depending on the testing requirements, in other embodiments, the fit can be flexibly adjusted, with a clearance fit between the test piece 500 and the mounting base 200, and a transition fit between the test piece 500 and the rotor 300. This configuration aims to simulate the localized load conditions borne by the elastic support structure during actual operation of an aero-engine. Specifically, among the multiple second protrusions 520 on the test piece 500, only the circumferential half-circumferential region contacts the mounting base 200 and bears the load, while the remaining half-circumference is in a non-contact state. Therefore, the load distribution borne by the test piece 500 exhibits a semi-sine shape.

[0038] Therefore, in this embodiment, when the rotor 300 generates a rotational excitation force field under the drive of the excitation unit 400 and transmits it to the test piece 500, due to the objective existence of the gap, the test piece 500 only makes extrusion contact with the mating surface and bears the load in the radial direction in a local area on the force-bearing side, while on the opposite side in the force direction, it remains dynamically separated from the contact surface, so as to construct a half-cycle force state that changes synchronously and periodically with the excitation force field. In this way, the mechanical response characteristics of the engine in real operation are reproduced with high fidelity under the test environment, which greatly improves the authenticity of the simulation test and the reliability of the conclusion.

[0039] Further, refer to Figure 4 and Figure 5 The test piece 500 is mounted on the force transmission boss 330 of the rotor 300.

[0040] Further, refer to Figure 1 and Figure 2 The support platform 100 may include a rectangular base plate and a rigid support frame 130 extending upward from the base plate, the top of which is a ring structure 110.

[0041] Further, refer to Figure 3 and Figure 4 The top annular structure 110 of the support frame 130 and the mounting base 200 can be fixedly connected via an adapter 120. Specifically, the adapter 120 is fastened to the top end face of the support frame 130 by bolts distributed along its circumference. An annular fixing protrusion 121 is provided on the end face of the adapter 120 opposite to the support frame 130, and the mounting base 200 is fixed to the annular fixing protrusion 121 by bolts distributed along its circumference.

[0042] In addition, refer to Figure 4 and Figure 5 The mounting base 200 may have an extension 230 extending into the inner ring space of the support frame 130. The aforementioned mounting through hole 210 is formed in the extension 230, so that the mounting through hole 210 is completely sunk into and located in the inner ring space of the support frame 130, and remains coaxial with the inner ring space.

[0043] In an optional embodiment, refer to Figures 5 to 8 The test piece 500 may also include a limiting structure, which can cooperate with the mounting base 200 to limit the rotation of the test piece 500 relative to the mounting base 200, ensuring that the position of the test piece 500 remains stable during the process of bearing high-frequency excitation load, and effectively preventing the unexpected rotation or position drift of the test piece 500 due to vibration torque or inertia.

[0044] Furthermore, refer to 4 and Figure 5An annular limiting protrusion 250 is formed on the inner side of the mounting hole, for reference. Figure 4 The elastic ring abuts against the annular limiting protrusion 250. (Review) Figure 5 Furthermore, a retaining ring 240 can be provided on the mounting base 200, combined with... Figure 9 The retaining ring 240 can be fixed to the end of the extension 230, so that the test piece 500 is clamped and fixed between the retaining ring 240 and the limiting protrusion.

[0045] Further, refer to Figure 5 The inner end face of the annular limiting protrusion 250 forms a limiting groove 220, which can penetrate the annular limiting protrusion 250 along the first direction. Correspondingly, refer to Figure 7 The edge of the test piece 500 forms a limiting protrusion 530, combined with Figure 8 The limiting protrusion 530 engages with the limiting groove 220, thereby restricting the rotation of the test piece 500 relative to the mounting base 200.

[0046] In an optional embodiment, refer to Figure 2 and Figure 3 The rotor 300 has a first end 310 and a second end 320 disposed opposite to each other. The excitation unit 400 specifically includes a first exciter 410 and a second exciter 420. The first exciter 410 is adapted to apply an excitation force along a first axial direction to the first end 310 and the second end 320 of the rotor 300; the second exciter 420 is adapted to apply an excitation force along a second axial direction to the first end 310 and the second end 320 of the rotor 300. Both the first axial direction and the second axial direction are perpendicular to the axial extension direction of the rotor 300, and the first axial direction and the second axial direction are orthogonally distributed, i.e., perpendicular to each other.

[0047] Therefore, this embodiment, through the above structure, can achieve the input of dynamic excitation loads with independently adjustable initial phase, amplitude, and frequency to both ends of the rotor 300 in two mutually perpendicular dimensions. By vector synthesis of the excitation force fields applied to both ends of the shaft by the first exciter 410 and the second exciter 420, the motion trajectory of the rotor 300's center of mass can be controlled, thereby faithfully reproducing the dynamic characteristics of the aero-engine rotor system during actual operation under experimental conditions.

[0048] It is understandable that when the first exciter 410 and the second exciter 420 act synchronously on both ends of the rotor 300 with a preset frequency, phase difference and amplitude, the resultant force generated will guide the center of mass of the rotor 300 to produce a circular rotation or elliptical trajectory.

[0049] Therefore, this embodiment achieves precise input of dynamic loads at both ends of the rotor 300 by using a first exciter 410 and a second exciter 420 that are perpendicular to each other. Furthermore, through force field synthesis technology, the motion trajectory of the rotor 300's center of mass can flexibly simulate the actual motion process of the engine under various extreme and complex working conditions.

[0050] Specifically, refer to Figures 1 to 3 In this embodiment, the initial phase, amplitude and frequency of the vibrator can be adjusted by the vibration control system 360 to control the motion trajectory of the rotor 300's center of mass.

[0051] Furthermore, combined Figure 14 The first exciter 410 has a first vibration period, and the second exciter 420 has a second vibration period, the first vibration period and the second vibration period being the same. The first exciter 410 having a first vibration period and the second exciter 420 having a second vibration period, and the first vibration period being the same as the second vibration period, ensures that the excitation forces in the two orthogonal directions maintain a high degree of synchronization and frequency consistency in the time dimension, thereby providing the necessary time and frequency basis for synthesizing a stable and continuous excitation force field on the rotor 300.

[0052] Therefore, in this embodiment, by making the working cycles of the first exciter 410 and the second exciter 420 completely equal, the rotor 300 is subjected to harmonic excitation with completely consistent frequencies in two mutually perpendicular axes. (Reference) Figure 14 According to the theory of vibration synthesis, when two simple harmonic vibrations that are perpendicular to each other and have the same frequency are superimposed, the trajectory of the end of their resultant force vector will form a stable closed curve.

[0053] Therefore, under the premise of frequency synchronization, this embodiment can accurately generate the required circular or elliptical rotating force vector trajectory by further adjusting the phase difference between the two. If the periods of the two exciters are inconsistent, the synthesized force field will produce phase drift or beat frequency phenomenon, causing the trajectory of the applied load to evolve disorderly over time, making it impossible to truly simulate the force state of the engine during steady-state operation.

[0054] Furthermore, the first exciter 410 has a first amplitude and a first initial phase, and the second exciter 420 has a second amplitude and a second initial phase. The first amplitude and the second amplitude are equal, and the first initial phase and the second initial phase differ by 90°. Thus, the composite motion trajectory of the center of mass of the rotor 300 can be circular.

[0055] The specific principles are as follows: Two exciters apply the excitation force to the elastic ring via a simulated rotor 300, wherein the excitation force is adjusted by the exciter control system to regulate the amplitude, frequency and phase of the excitation force.

[0056] The expression for the excitation force is as follows: Exciter excitation force: (1) Exciter excitation force: (2) In the formula, The excitation force of the first exciter. This is the excitation force for the second exciter; The amplitude of the first excitation force. This is the second excitation force amplitude; This is the initial phase of the first excitation force. ω is the initial phase of the second excitation force; ω is the excitation angular frequency of the exciter (i.e., the excitation period).

[0057] The test system is approximated as a forced vibration of a single-degree-of-freedom system, and the excitation forces of the two exciters are defined by the vibration differential equation of the system: (3) (4) In the formula, , To simulate the excitation displacement of rotor 300; , The structural damping coefficient is the system's vibration direction. , To simulate the support stiffness between rotor 300 and the elastic ring, m is the moving mass of the test system.

[0058] Solving equation (3) for vibration differential equation yields a complete solution including a general solution. and a special solution .

[0059] General solution The solution corresponding to the homogeneous equation for damped free vibration, in the underdamped state, is a damped vibration, a transient vibration that quickly decays and stops. Particular solution. For excitation force Forced vibrations are generated under excitation, and the particular solution can be expressed as: (5) In the formula, To simulate rotor 300 in Amplitude under excitation To simulate the phase difference between the rotor's 300 vibration displacement and the excitation force.

[0060] Similarly, the particular solution of equation (4) can be obtained. : (6) , This refers to the parameters that need to be achieved when adjusting the load on the vibrator. These parameters can be obtained through acceleration or displacement sensors. During the test, the vibration control system 460 controls and adjusts the excitation force amplitude of the two vibrators. , Excitation frequency ω, initial phase This causes the simulated rotor 300 to undergo excitation displacement. , The required values ​​for the experiment were achieved.

[0061] Therefore, the excitation force of the two exciters , Simultaneously acting on the simulated rotor 300 , This is equivalent to simulating rotor 300 undergoing simple harmonic motion with a frequency of ω in two mutually perpendicular directions. When , When the amplitudes are not equal, the trajectory of the center of mass of the simulated rotor 300 is as follows Figure 14 The ellipse in the middle. Therefore, when , The amplitudes are exactly equal and and When the phase difference is 90°, the motion trajectory of the center of mass of the simulated rotor 300 is circular. Therefore, this embodiment can utilize the excitation force of two exciters. , A rotational force field is simulated to be applied to the simulated rotor 300.

[0062] In an optional embodiment, refer to Figure 6 , Figure 9 and Figure 11 The fatigue performance testing device further includes a strain gauge 600. Along the circumferential direction of the test piece 500, there are bonding positions with the minimum stress gradient in the region between adjacent second bosses 520 (i.e., outer bosses), and the strain gauge 600 is bonded at any of these bonding positions.

[0063] The strain gauge 600 can collect and record the local stress state of its area under the action of a dynamic rotating excitation force field in real time, and calculate the limit stress level at the maximum stress location of the test piece 500 through a pre-set sensitivity coefficient, thereby evaluating the fatigue life and performance indicators of the test piece 500.

[0064] Specifically, the test piece 500 has an inner ring first boss 510 and an outer ring second boss 520. When subjected to rotational excitation force, the rounded transition area at the root of the bosses experiences significant stress concentration due to structural abrupt changes, becoming the most stressful and fatigue-damage-prone area in the overall structure. However, the stress gradient at this point of maximum stress is extremely high. If the strain gauge 600 is directly attached at this location, even a small positional deviation or attachment angle error will lead to significant distortion of the measurement results. At the same time, the extremely high local strain extreme value can also easily cause fatigue damage or detachment of the strain gauge 600 during high-frequency excitation.

[0065] It should be noted that different structures have different sensitivity coefficients. Therefore, it is necessary to analyze the specific structure to determine the corresponding sensitivity coefficient. To this end, this embodiment uses appropriate methods such as finite element simulation or experimental calibration to predetermine the stress ratio between the low-stress gradient pasting area and the maximum stress point of the fillet, and defines it as the sensitivity coefficient.

[0066] Therefore, in this embodiment, the strain gauge 600 acquires stable vibration stress signals in the low stress gradient region in real time. Since this region is insensitive to the accuracy of the bonding position and avoids high strain areas, it not only ensures extremely high repeatability and stability of the test data but also significantly extends the service life of the strain gauge 600, avoiding test interruptions due to sensor failure. Subsequently, based on the pre-calibrated sensitivity coefficient, the acquired stress values ​​can be accurately converted to derive the true ultimate stress level at the maximum stress point, which can then be used to evaluate the fatigue life and performance indicators of the test piece 500.

[0067] In an optional embodiment, refer to Figure 9 The mounting base 200 has a recess on its 250 side. The strain gauge 600 is located between the recess and the test piece 500 along the radial direction of the test piece 500, so as to leave space for the strain gauge 600 and other structures.

[0068] Specifically, refer to Figure 9 The strain gauge 600 has lead terminals connected to cables. The fatigue performance testing device also includes a receiving unit electrically connected to the lead terminals via the cables. The aforementioned recess provides ample installation and clearance space for the strain gauge 600 and its lead terminals and other auxiliary structures within a limited assembly gap, thereby ensuring the integrity and safety of the entire signal acquisition circuit.

[0069] Further, refer to Figure 9The recess can be specifically constructed as a notch formed on the body of the mounting base 200. This notch can be located on the extension 230 of the mounting base. The geometry, opening size, and specific distribution position of the notch on the mounting base 200 can be adaptively designed and flexibly adjusted according to the actual physical specifications, wiring paths, and assembly clearance space requirements of the strain gauge 600 and other structures. This application does not impose strict limitations on these aspects.

[0070] Furthermore, the aforementioned receiving unit can specifically be a dynamic strain gauge, a high-frequency data acquisition card, or an industrial control computer with integrated signal amplification and processing functions. Its main function is to receive the weak electrical signals (such as changes in resistance or voltage) generated by the strain gauge 600 under stress and deformation, and then connect them to the system via cables for signal amplification, analog-to-digital conversion, and real-time recording. Ultimately, the electrical signals are accurately converted into intuitive stress or strain curves for testing personnel to analyze the stress and fatigue performance of the test piece 500.

[0071] It should be mentioned that, due to the combined physical thickness of the strain gauge 600 itself, the strain adhesive used for fixing, and the lead terminals of the connecting cables, this total thickness is very likely to exceed the height of the second protrusion 520 on the outer ring of the test piece 500 after actual mounting. This means that the strain gauge 600 and related structures will protrude beyond the outer contour surface of the test piece 500. If no corresponding clearance or lead-out space is designed on the external mounting base 200, the protruding part of the test piece 500 with the strain gauge 600 will inevitably cause strong mechanical interference with the inner wall of the mounting base 200 when it is inserted into the mounting through hole 210.

[0072] Therefore, this embodiment provides sufficient radial clearance and cable lead-out space for the strain gauge 600, adhesive layer and lead terminal with a certain thickness by specifically designing a cable outlet recess (notch) on the mounting base 200, thereby enabling the strain gauge 600 to be placed between the test piece and the mounting base 200.

[0073] In an optional embodiment, the first force transmission structure 430 has a first connecting end 431 and a second connecting end 432, which are respectively connected to the opposite ends of the rotor 300; similarly, the second force transmission structure 440 has a third connecting end 441 and a fourth connecting end 442, which are also respectively connected to the opposite ends of the rotor 300.

[0074] Specifically, in this embodiment, both the first force transmission structure 430 and the second force transmission structure 440 can be constructed as force transmission fork structures. Taking the first force transmission structure 430 as an example, the main body end of the force transmission fork is connected to the vibration end of the aforementioned first exciter 410 to receive the excitation force, and the side away from the exciter branches out into two parallel branch arms. The ends of these two branch arms respectively constitute the aforementioned first connecting end 431 and second connecting end 432. Similarly, the second force transmission structure 440 also adopts a force transmission fork structure, and the ends of the two branch arms formed by its branching form the aforementioned third connecting end 441 and fourth connecting end 442.

[0075] Therefore, this embodiment can achieve the same excitation force applied to both ends of the excitation rotor 300 by a single exciter, thereby effectively avoiding the axial deviation, warping or additional bending moment of the rotor 300 that may be caused by single-end loading, and ensuring that the rotor 300 can maintain perfect spatial parallel movement or controlled orbital motion when subjected to high-frequency excitation.

[0076] Furthermore, both ends of the rotor 300 are fixed with mounting bases 450, each mounting base 450 having a through hole for the ends of the rotor 300 to pass through. The portion of the rotor 300 passing through the mounting base 450 is secured with bolts. The mounting base 450 includes a first end 310 surface and a second end 320 surface arranged at a perpendicular angle. The first connecting end 431 and the third connecting end 441 are respectively fixed to the first end 310 surface and the second end 320 surface of the mounting base 450 at the first end 310 of the rotor 300 with bolts. Correspondingly, the second connecting end 432 and the fourth connecting end 442 are respectively fixed to the first end 310 surface and the second end 320 surface of the mounting base 450 at the second end 320 of the rotor 300 with bolts.

[0077] Furthermore, both ends of the rotor 300 are fixed with mounting bases 450, and each mounting base 450 has a through hole for the corresponding end of the rotor 300 to pass through. The portion of the rotor 300 that passes through the mounting base 450 is secured with bolts to achieve a reliable rigid connection between the rotor 300 and the mounting base 450. In addition, the outer periphery of the mounting base 450 includes a first end surface 310 and a second end surface 320 arranged at a perpendicular angle.

[0078] Furthermore, the fixing base 450 can be in the form of a cube. In this case, its two adjacent sides can be adapted to be the first end 310 face and the second end 320 face.

[0079] In conjunction with the aforementioned force transmission fork structure, the first connecting end 431 of the first force transmission structure 430 and the third connecting end 441 of the second force transmission structure 440 can be fixed to the first end 310 surface and the second end 320 surface of the fixing seat 450 of the first end 310 of the rotor 300 by bolts respectively; correspondingly, the second connecting end 432 of the first force transmission structure 430 and the fourth connecting end 442 of the second force transmission structure 440 can be fixed to the first end 310 surface and the second end 320 surface of the fixing seat 450 of the second end 320 of the rotor 300 by bolts respectively.

[0080] Furthermore, there is a gap between the fixed base 450 and the first force transmission structure 430 and the second force transmission structure 440. In this embodiment, an adjusting shim can be installed in the gap, and this shim adjustment process is equivalent to self-aligning between the front and rear supports on the engine.

[0081] Further, refer to Figure 1 and Figure 2 Force sensors are installed on both the first force transmission structure 430 and the second force transmission structure 440. The magnitude of the excitation force field formed by the two mutually perpendicular exciters is detected by the force sensor 800. The operator can use the data measured by the force sensor 800 as follows: Figure 12 The data shown is used to further adjust the exciter so that the magnitude of the excitation force field formed by the two reaches the preset value.

[0082] In an optional embodiment, the fatigue performance testing device further includes a first detection unit adapted to measure the excitation displacement at both ends of the rotor 300. In a specific implementation, the first detection unit is preferably a laser displacement sensor, symmetrically arranged on both sides of the support frame 130 along a first direction.

[0083] refer to Figures 2 to 5 Since the aforementioned fixed base 450 is rigidly fixed to the end of the rotor 300, the first detection unit can directly detect the dynamic displacement of the fixed base 450, thereby accurately characterizing the macroscopic displacement trajectory of the rotor 300, and further reflecting the excitation load level applied by the exciter to the test piece 500 through displacement data. During the test, this embodiment can adjust the input parameters such as the excitation frequency and amplitude of the exciter so that the excitation displacement at both fixed bases 450 reaches the preset value required by the test, thereby achieving control of the excitation state.

[0084] Furthermore, the first detection unit may include a displacement sensor.

[0085] However, it should be noted that the excitation displacement parameters obtained from the aforementioned fixed base 450 can only represent the overall motion response of the rotor 300. Considering the unavoidable assembly gaps on the force transmission path and structural mating surfaces, the macroscopic excitation displacement of the rotor 300 cannot directly and equivalently reflect the actual stress and local deformation of the test component 500 (i.e., the elastic ring). Therefore, this embodiment can combine the displacement data measured by the first detection unit with the microscopic local stress data measured by the aforementioned strain gauge 600 to comprehensively and accurately reflect and restore the actual stress and deformation state of the test component 500 under complex vibration environment.

[0086] In an optional embodiment, the fatigue performance testing device further includes a second detection unit, which is adapted to measure the acceleration at both ends of the rotor 300. In a specific implementation, when using an acceleration measurement scheme to obtain displacement, the second detection unit is preferably a triaxial vibration accelerometer. This triaxial vibration accelerometer is respectively mounted on the corresponding fixed bases 450 at both ends of the rotor 300 to acquire vibration acceleration data in the corresponding excitation direction of the vibrator in real time, for example... Figure 13 The corresponding data shown in the document.

[0087] After the test system acquires the acceleration signal, it can perform two time integration calculations on the acceleration data using built-in analysis software to obtain the excitation displacement of the fixed seat in the excitation direction of 450°.

[0088] Furthermore, since the fixed base 450 and the end of the rotor 300 are rigidly and securely connected without gaps through bolts or other structures, they maintain absolute consistency in motion during vibration. Therefore, the displacement at the fixed base 450 obtained by acceleration integration can accurately and realistically reflect the true macroscopic displacement of the rotor 300 as a whole in the corresponding excitation direction, thus providing richer dynamic data support for comprehensively evaluating the stress and deformation of the test piece 500 under complex dynamic force fields. Of course, in this embodiment, this displacement data is combined with the microscopic local stress data measured by the aforementioned strain gauge 600 to comprehensively and accurately reflect and restore the actual stress and deformation state of the test piece 500 under complex excitation environment.

[0089] Therefore, this embodiment can determine the fatigue limit of the test piece 500 by measuring the force and deformation of the test piece 500, thereby determining the performance of the test piece 500.

[0090] In an optional embodiment, refer to Figure 10 The fatigue performance testing device is equipped with a positioning bushing 700 for auxiliary assembly positioning.

[0091] The positioning bushing 700 has a ring-shaped structure with an assembly positioning structure that corresponds to the part to be tested 500. It can be fastened to the mounting base 200 by bolts. This application does not strictly limit the specific model or geometric dimensions of the positioning bushing 700. In practical applications, those skilled in the art can select or customize the bushing based on the outer diameter of the actual rotor 300 of the engine to be simulated and the inner diameter of the mounting through hole 210 of the mounting base 200.

[0092] refer to Figure 10 In the pre-assembly stage before the formal installation of the test piece 500, the positioning bushing 700 is fixedly installed on the mounting base 200 by bolts, and the part of it that forms an assembly positioning structure corresponding to the test piece 500 extends into the space where the test piece 500 will be installed, thus serving as a reference for installing the rotor 300.

[0093] To make the structural features and engineering implementation process of the present invention clearer, this embodiment further explains the assembly method of the fatigue performance testing device.

[0094] First, the test platform, the first exciter 410 and the second exciter 420, the force sensor, the first force transmission structure 430 and the second force transmission structure 440 are mechanically connected and rigidly fixed to form a stable power output and force transmission link; at the same time, the adapter 120 and the mounting base 200 are connected and fixed in sequence.

[0095] Subsequently, the positioning bushing 700 is assembled onto the mounting base 200, and a portion of it having the same structure as the test piece 500 is temporarily placed within the mounting through hole 210 of the mounting base 200. After this is completed, the rotor 300 is inserted through the mounting through hole 210, so that the force transmission boss in the middle of the rotor 300 is axially limited by the positioning bushing 700, thereby initially establishing the spatial reference position of the rotor 300. Based on this, the fixing bases 450 are respectively installed at both ends of the rotor 300, and the fitting clearance between the end face of the fixing base 450 and the first force transmission structure 430 and the second force transmission structure 440 is measured using measuring tools such as feeler gauges. According to the measurement results, adjusting shims of matching thickness are configured at the corresponding clearances to achieve clearance compensation and system alignment, thereby eliminating manufacturing and assembly accumulated tolerances and avoiding parasitic bending moments introduced by initial misalignment, ensuring that the excitation load can be stably and without distortion transmitted to the rotor 300 along the preset direction.

[0096] After completing the above position calibration and relationship solidification, the positioning bushing 700 is removed from the mounting base 200, and the test piece 500 is installed in the corresponding position. At the same time, the upper limit protrusion 530 of the test piece 500 is embedded in the limiting groove 220 of the mounting base 200 to form a circumferential limiting constraint. Finally, the test piece 500 is axially locked and fixed by the retaining ring 240, thereby completing the entire assembly process.

[0097] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A fatigue performance testing apparatus, characterized by, include: Support platform (100); Mounting base (200), the mounting base (200) is disposed on the support platform (100), the mounting base (200) has a mounting through hole (210) extending along a first direction; A rotor (300) coaxially passes through the mounting through hole (210) and is at least partially located within the mounting through hole (210); Excitation unit (400), the excitation unit (400) is connected to and supported at both ends of the rotor (300), the excitation unit (400) is adapted to form an excitation force field at both ends of the rotor (300); The test piece (500) is sleeved on the rotor (300) and located in the mounting through hole (210). The test piece (500) has a first boss (510) located on its inner ring and a second boss (520) located on its outer ring. The excitation force field is applied to the test piece (500) through the rotor (300).

2. The fatigue performance testing apparatus of claim 1, wherein, The rotor (300) has a first end (310) and a second end (320), and the excitation unit (400) includes a first exciter (410) and a second exciter (420). The first exciter (410) is adapted to apply an excitation force along a first axial direction to the first end (310) and the second end (320), and the second exciter (420) is adapted to apply an excitation force along a second axial direction to the first end (310) and the second end (320). The first axial direction and the second axial direction are both perpendicular to the first direction, and the first axial direction and the second axial direction are perpendicular.

3. The fatigue performance testing apparatus of claim 2, wherein, The first exciter (410) has a first vibration period, and the second exciter (420) has a second vibration period, the first vibration period and the second vibration period are the same.

4. The fatigue performance testing apparatus of claim 3, wherein, The first exciter (410) has a first amplitude and a first initial phase, and the second exciter (420) has a second amplitude and a second initial phase. The first amplitude and the second amplitude are equal, and the first initial phase and the second initial phase are 90° apart.

5. The fatigue performance testing apparatus according to any one of claims 1 to 4, characterized by, The test piece (500) includes a limiting structure that engages with the mounting base (200) to limit the rotation of the test piece (500) relative to the mounting base (200).

6. The fatigue performance testing apparatus according to any one of claims 1 to 4, characterized by The fatigue performance testing device includes strain gauges (600). Along the circumference of the test piece (500), there are bonding positions with the minimum stress gradient between adjacent outer protrusions. The strain gauges (600) are bonded at any bonding position. The strain gauges (600) are suitable for feeding back the stress at the bonding position.

7. The fatigue performance testing apparatus of claim 6, wherein, The inner side of the mounting through hole (210) is provided with a recess. The strain gauge (600) is located between the recess and the test piece (500) along the radial direction of the test piece (500). The strain gauge (600) has a lead terminal, and the lead terminal is connected to a cable. The fatigue performance testing device also includes a receiving unit, which is electrically connected to the lead terminal through the cable.

8. The fatigue performance testing apparatus according to any one of claims 1 to 4, characterized by The excitation unit (400) includes a first exciter (410) and a second exciter (420). The excitation unit (400) also includes a first force transmission structure (430) and a second force transmission structure (440). The first force transmission structure (430) extends along a first axial direction, and the second force transmission structure (440) extends along a second axial direction. The first axial direction and the second axial direction are perpendicular to each other. The first force transmission structure (430) has a first connecting end (431) and a second connecting end (432), which are connected to the two ends of the rotor (300) respectively; the second force transmission structure (440) has a third connecting end (441) and a fourth connecting end (442), which are connected to the two ends of the rotor (300) respectively.

9. The fatigue performance testing apparatus of claim 8, wherein, The fatigue performance testing device also includes a first detection unit, which is suitable for measuring the excitation displacement at both ends of the rotor (300).

10. The fatigue performance testing apparatus of claim 8, wherein, The fatigue performance testing device also includes a second detection unit, which is suitable for measuring the acceleration at both ends of the rotor (300).

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