Method for decomposing strength test load of intermediate casing in aero-engine and loading system

Abstract

The present application relates to the technical field of aero-engine test, and especially relates to a method for decomposing a strength test load of an intermediate casing of an aero-engine and a loading system. The present application solves the technical problem that a large number of additional torques are generated and a large number of actuating cylinders are configured due to the fact that an installation edge bears six-component combined loads Fx, Fy, Fz, Mx, My and Mz and the six-component combined loads are loaded one by one in the prior art. The technical scheme of the present application is as follows: the six-component loads borne by the installation edge are mechanically decoupled and synthesized; the axial force Fx is symmetrically decomposed into two equal forces, which are applied by two actuating cylinders; the lateral force Fy, the bending moment Mx and the torque Mz are combined in four lateral component forces, a force and torque balance equation set is established by using force arm combination in different directions to solve the values of the component forces, and three loadings are synchronously completed by two actuating cylinders; the normal force Fz and the bending moment My are combined in two normal component forces, an equation set is established by using force arm combination to solve, and two loadings are synchronously completed by two actuating cylinders.

Description

Technical Field

[0001] This invention relates to the field of aero-engine testing technology, and in particular to a method for decomposing the load for aero-engine intermediate casing strength test and a loading system. Background Technology

[0002] The engine casing is a critical load-bearing component of the engine, and its structural strength, fatigue life, and stiffness characteristics play a decisive role in the overall performance, service life, and flight safety of the engine. According to relevant standards, before flight testing and type certification of an aero-engine, strength and life testing must be conducted on critical load-bearing components such as the casing. The intermediate casing, as the core hub connecting the fan casing, outer bypass duct, high-pressure compressor, and bearing housing, has a complex structure. Under typical operating conditions, the mounting edge must simultaneously withstand a six-component composite load consisting of axial force Fx, lateral force Fy, normal force Fz, and bending moments Mx, My, and torques Mz around each axis. Figure 1 As shown, the parts on the intermediate casing that need to bear the load include the front mounting edge A (fan casing mounting edge), the rear mounting edge B (outer bypass casing mounting edge), the splitter ring mounting edge C, the No. 2 pivot bearing seat mounting edge D, the No. 3 pivot bearing seat E, the left main mounting section I, the right main mounting section J, and the auxiliary casing mounting bracket G.

[0003] In existing static strength tests, directly applying loads to each load component of a specific mounting edge independently presents significant technical bottlenecks. First, when applying a single concentrated force (e.g., Fy), unintended additional moments inevitably arise because the point of application of the force usually does not coincide with the stiffness center of the mounting edge of the casing. To eliminate these additional moments and ensure loading accuracy, testers must additionally configure multiple actuators for moment compensation, drastically increasing the total number of actuators required in the loading scheme. Second, the numerous pipes and accessories around the intermediate casing result in extremely limited operating space. The dense arrangement of numerous actuators easily leads to spatial geometric interference, not only preventing the physical installation of the loading device and hindering the smooth conduct of the test, but also significantly increasing the complexity of the test system, debugging time, and economic costs. Therefore, a load decomposition method that can comprehensively consider multi-axis loads, reduce the number of actuators, and eliminate additional moments is urgently needed. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that in the static strength test of the intermediate casing of the existing aero-engine, due to the complex force on the mounting edge and the small space, applying single-axis load one by one will result in additional torque, require a large number of actuators and easily cause spatial interference, thus causing high test costs or even making the test impossible.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: On one hand, this invention provides a load decomposition method for strength testing of an aero-engine intermediate casing. The technical solution involves mechanically decoupling and synthesizing the six-component composite load borne by the mounting edge. Through specific spatial locations and a specific number of loading points, utilizing the principles of couples and symmetrical loading, multiple predetermined load components are applied simultaneously with a small number of actuators without generating additional torque. For the most complex load conditions borne by the mounting edge, namely the typical case of bearing forces Fx, Fy, and Fz in three directions and moments Mx, My, and Mz in three directions, load decomposition is performed. The method includes the following steps: S1: A rigid transition section is fitted on the mounting edge of the intermediate casing to be tested, and several loading heads with defined spatial coordinate positions are constructed on the transition section; S2: Application of Axial Force Fx. The target axial force Fx is decomposed into two equal forces and applied symmetrically. Specifically, the axial force Fx is decomposed into a first axial component Fx1 and a second axial component Fx2, where Fx1 equals Fx2, i.e., Fx = Fx1 + Fx2, and Fx1 = Fx2. Fx1 and Fx2 are arranged symmetrically with respect to the coordinate origin of the mounting edge and applied through two actuators respectively. In this way, since the two component forces are equal in magnitude and symmetrically arranged, their resultant force passes through the coordinate origin, thus no additional bending moment or torque is generated when the axial force Fx is applied.

[0006] S3: Joint application of lateral force Fy, bending moment Mx, and torque Mz. Since applying load Fy alone results in additional bending moment and torque due to the point of application deviating from the origin, this invention takes the opposite approach, simultaneously loading Mx and Mz during the application of Fy. Specifically, the lateral force Fy is decomposed into four components: the first lateral component Fy1, the second lateral component Fy2, the third lateral component Fy3, and the fourth lateral component Fy4. By pre-setting the spatial positions of each loading point, the lever arm length of each component force relative to the coordinate origin is determined, thereby establishing three mechanical equilibrium equations satisfied by the magnitudes and lever arm lengths of Fy1, Fy2, Fy3, and Fy4: The first equation is the resultant force equation of the total transverse force, satisfying Fy=(Fy1+Fy2)-(Fy3+Fy4); the second equation is the bending moment equation about the X-axis, assuming the lever arm length of each component force in the Z-axis direction is b2, satisfying Mx=(Fy1+Fy2)×b2+(Fy3+Fy4)×b2; the third equation is the torque equation about the Z-axis, assuming the lever arm length of some component forces in the X-axis direction is c1, and the lever arm length of another component force in the X-axis direction is c2, satisfying Mz=(Fy2-Fy4)×c1+(Fy1+Fy3)×c2. By solving the three equations simultaneously and considering the selected lever arm lengths b2, c1, and c2, the magnitudes of the component forces Fy1, Fy2, Fy3, and Fy4 can be determined. During actual loading, the component forces parallel to the Y-axis among Fy1, Fy2, Fy3, and Fy4 can be combined, requiring only two actuators to synchronously load the three load components Fy, Mx, and Mz.

[0007] S4: Joint application of normal force Fz and bending moment My. Since applying the vertical force Fz alone will also generate an additional bending moment due to the deviation of the point of application from the origin, this invention utilizes the application process of Fz to simultaneously load My. Specifically, the normal force Fz is decomposed into two components: the first normal component Fz1 and the second normal component Fz2. By pre-setting the spatial positions of the two loading points, the lever arm lengths a1 and a2 in the X-axis direction are determined, thereby establishing two mechanical equilibrium equations satisfied by the magnitudes of Fz1 and Fz2 and their lever arm lengths: the first equation is the resultant force equation of the total normal force, satisfying Fz = Fz2 - Fz1; the second equation is the bending moment equation about the Y-axis, satisfying My = Fz1 × a1 - Fz2 × a2. By simultaneously solving these two equations and combining them with the selected lever arm lengths a1 and a2, the numerical values ​​of Fz1 and Fz2 can be determined. Only two actuators are needed to simultaneously load the two load components, Fz and My.

[0008] By organically combining the above steps, a total of 6 actuators are needed to apply all six components of the load on a typical mounting edge: 2 actuators are needed for applying the axial force Fx, 2 actuators are needed for the combined application of the lateral force Fy, bending moment Mx, and torque Mz, and 2 actuators are needed for the combined application of the normal force Fz and bending moment My. This scheme simplifies the complex load-loading task that originally required a large number of actuators to be completed with only 6 actuators, fundamentally solving the problem of interference in the test space.

[0009] As a further implementation of this technical solution, based on the above load decomposition approach and the specific numerical value of the target load, the lengths of the lever arms b2, c1, c2, a1, and a2 are first determined. Then, by substituting these values ​​into the various mechanical equilibrium equations, the magnitude of each decomposed load is determined. The selection of the lever arm length needs to comprehensively consider factors such as the geometric dimensions of the mounting flange, the structural design space of the transition section, and the rationality of the magnitude of each component force.

[0010] As a further implementation of this technical solution, in step S3, after solving for each component force value, the component forces in the same direction can be combined during loading. For example, if Fy1 and Fy2 are both in the positive Y-axis direction, and their loading heads can be linked by a lever mechanism, then these two forces can be output simultaneously by one actuator; similarly, Fy3 and Fy4 are also applied uniformly by another actuator. This further reduces the actual number of actuators used and simplifies the complexity of the loading system.

[0011] Secondly, the present invention provides a loading system for a strength test load of an aero-engine intermediate casing, applying the above-mentioned decomposition method for the strength test load of an aero-engine intermediate casing, the system comprising: A rigid adapter section is used to secure it to the mounting edge of the intermediate housing to be tested; At least six actuators are connected to loading heads at pre-set coordinate positions on the rigid transition section; The control system is used to control the actuator to load according to the decomposed force values, so as to jointly simulate the six-component load of the target.

[0012] Preferably, of the six actuators, two are used to apply the decomposed first axial component force Fx1 and second axial component force Fx2; two are used to apply the decomposed first normal component force Fz1 and second normal component force Fz2; one is used to apply the resultant force of the first lateral component force Fy1 and the second lateral component force Fy2; and one is used to apply the resultant force of the third lateral component force Fy3 and the fourth lateral component force Fy4.

[0013] Compared with the prior art, the beneficial technical effects of the present invention are reflected in the following aspects: First, by adopting the load decomposition method of this invention, all loads borne by the mounting edge of the intermediate casing can be systematically decomposed according to this method. Regardless of how the magnitude and direction of the forces Fx, Fy, Fz and the moments Mx, My, Mz borne by the mounting edge change, this method can flexibly adapt to load decomposition by adjusting the lever arm parameters and the values ​​of each component force. It can meet the test decomposition requirements of multi-axis loads formed by different combinations of mechanical and aerodynamic loads, and has extremely strong versatility and universality.

[0014] Secondly, this invention creatively establishes a mechanical decoupling and synthesis model for multiaxial loads, cleverly merging load components that originally required multiple independent actuators to apply and compensate for separately into a single set of loading paths for collaborative implementation. Specifically, the application process of Fy simultaneously completes the loading of Mx and Mz, and the application process of Fz simultaneously completes the loading of My, significantly reducing the total number of actuators required to complete a six-component load test on a single mounting edge to six. This fundamentally solves the spatial interference problem caused by an excessive number of actuators, making experiments that were previously impossible due to space constraints feasible.

[0015] Third, the load decomposition method of the present invention ensures that the resultant force line of each component force passes through the origin of the installation side coordinate or is accurately generated by force couple during the design stage. No additional unexpected torque will be generated during the loading process, which ensures the accuracy of the test load application and makes the test results more accurate and reliable.

[0016] Fourth, by adopting the method of this invention, the number of actuators required for the test is significantly reduced, which correspondingly reduces the workload of actuator installation, debugging, and calibration, greatly lowering labor and time costs. At the same time, the load decomposition scheme has a definite mathematical expression, facilitating scheme design and verification by test personnel, and possesses significant economic value and engineering application prospects. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram showing the forces acting on each mounting edge of the intermediate casing.

[0019] Figure 2The following is a method for decomposing the load on a certain installation edge: (a) is a schematic diagram of the installation edge bearing a six-component load, with three directional forces Fx, Fy, and Fz and three directional moments Mx, My, and Mz marked in the figure; (b) is a schematic diagram of the axial force Fx being decomposed into two equal components Fx1 and Fx2 and symmetrically loaded; (c) is a schematic diagram of the normal force Fz being decomposed into Fz1 and Fz2, and the bending moment My being loaded simultaneously using different lever arms a1 and a2; (d) is a schematic diagram of the transverse force Fy being decomposed into Fy1, Fy2, Fy3, and Fy4, and the bending moment Mx and torque Mz being loaded simultaneously using lever arms b2, c1, and c2.

[0020] Figure 3 This is a schematic diagram of a scheme for applying load to the front mounting edge A using a designed rigid transition section and six actuators, as described in an embodiment of the present invention. Detailed Implementation

[0021] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0023] In static strength tests of aero-engines, the intermediate casing, as an important load-bearing component connecting and supporting the fan, outer bypass duct, and core engine, plays a crucial role in the safety design of the engine by verifying its structural integrity. Figure 1This diagram illustrates the structure of a typical intermediate casing and the load distribution along its mounting edges. It shows that the intermediate casing, located between the fan and the outer bypass duct, plays a crucial role in supporting and securing the engine. It has multiple mounting edges, including: front mounting edge A (fan casing mounting edge), rear mounting edge B (outer bypass casing mounting edge), splitter ring mounting edge C (high-pressure compressor No. 1 casing), No. 2 pivot bearing housing mounting edge D, No. 3 pivot bearing housing mounting edge E, left main mounting section I, right main mounting section J, and engine auxiliary casing mounting bracket G. Among these mounting edges, mounting edges A, B, C, and mounting bracket G all bear complete six-component loads: forces Fx, Fy, Fz and moments Mx, My, Mz, exhibiting the most complex stress state. Therefore, conducting structural strength tests on the intermediate casing under maximum flight loads requires simulating the application of complex loads to each of these mounting edges, and load decomposition is a crucial step before conducting the tests.

[0024] The core concept of this invention is to organically integrate the application requirements of multiple target load components into the same set of loading force systems through mechanical analysis, thereby minimizing the number of actuators required, avoiding spatial interference, and eliminating additional torque.

[0025] Detailed explanation of the method and principles The following example uses a typical mounting edge that bears the most complex load (i.e., the mounting edge that bears forces Fx, Fy, and Fz in all three directions and moments Mx, My, and Mz in all three directions), combined with... Figure 2 (a) to Figure 2 (d) The principle and steps of the load decomposition method of the present invention are described in detail. All loads are defined relative to a spatial rectangular coordinate system with the center of the mounting edge as the origin.

[0026] Step 1: Decomposition and Application of Axial Force Fx like Figure 2 As shown in (a), one of the loads borne by the mounting edge is an axial force Fx along the X-axis. In the traditional step-by-step loading method, if a concentrated force Fx is applied at only one point, additional bending moments will be generated around the Y-axis and Z-axis because the point of application may deviate from the coordinate zeros of the Y-axis and Z-axis. To eliminate these additional bending moments, an additional actuator is required to apply a reverse bending moment for compensation.

[0027] This invention solves this problem using the principle of symmetrical loading. For example... Figure 2 As shown in (b), the target axial force Fx is decomposed into two component forces Fx1 and Fx2. These two component forces are equal in magnitude, i.e., Fx1 = Fx2, and satisfy Fx = Fx1 + Fx2. The decomposed target force relationship is as follows: Fx = Fx1 + Fx2, and Fx1 = Fx2.

[0028] From the two relationships above, it can be seen that simply dividing the target force Fx by 2 yields the values ​​of Fx1 and Fx2. Geometrically, the loading points of Fx1 and Fx2 are arranged symmetrically with respect to the origin of the mounting edge coordinate system (usually located at the center of the mounting flange), for example, at two points equidistant from each other in the positive and negative Y-axis directions. In this way, the line of action of the resultant force of the two components passes precisely through the origin, generating only a pure axial force Fx in the X-axis direction, while the moments about the Y and Z axes are zero, thus preventing any additional bending or torque. This step requires two independent actuators to load Fx1 and Fx2 respectively.

[0029] Step 2: Joint decomposition and application of lateral force Fy, bending moment Mx, and torque Mz This is a key innovative step in the present invention that solves the technical problem of spatial interference and significantly reduces the number of actuators. For example... Figure 2 As shown in (a), the target load comprises three components: a lateral force Fy, a bending moment Mx about the X-axis, and a torque Mz about the Z-axis. In conventional methods, Fy must first be applied, then the resulting additional Mx and Mz must be measured, and finally, corresponding compensation torques must be added, requiring at least three independent loading subsystems. However, in the solution of this invention, the application requirements of these three target loads are considered holistically, and a set of precisely designed lateral components is used to achieve simultaneous loading of all three.

[0030] like Figure 2 As shown in (d), this invention designs four Y-axis (lateral) loading points on the mounting edge transition section, applying loads of the first lateral component Fy1, the second lateral component Fy2, the third lateral component Fy3, and the fourth lateral component Fy4, respectively. All four components act along the Y-axis, with Fy1 and Fy2 in the positive Y-axis direction and Fy3 and Fy4 in the negative Y-axis direction. By manually selecting the coordinate positions of each loading point in space, the lever arm length of each force relative to the coordinate origin can be determined. Specifically, let the lever arm length of all four loading points in the Z-axis direction be b2; in the X-axis direction, let the lever arm lengths of Fy2 and Fy4 be c1, and the lever arm lengths of Fy1 and Fy3 be c2.

[0031] Therefore, a set of mechanical equilibrium equations can be established, which satisfy the three target load components by these four component forces: The composition of the total lateral force Fy is: Fy = (Fy1 + Fy2) - (Fy3 + Fy4) ... (Equation 1); The bending moment Mx about the X-axis is generated by the lever arms of four forces in the Z-axis direction: Mx = (Fy1 + Fy2) × b2 + (Fy3 + Fy4) × b2 ………… (Equation 2); The torque Mz about the Z-axis is formed by the torque difference generated by four forces with different lever arms in the X-axis direction: Mz=(Fy2-Fy4)×c1+(Fy1+Fy3)×c2…………(Equation 3; In the above set of equations, the target loads Fy, Mx, and Mz are known quantities (given by the test task book), and the lever arm lengths b2, c1, and c2 can be reasonably selected based on the geometric dimensions of the installation side and the design space of the transition section. After selecting the lever arm length, the set of equations (1)-(3) contains four unknowns to be solved: Fy1, Fy2, Fy3, and Fy4. Since there are three equations and four unknowns, there is a design margin of one degree of freedom, which provides flexibility for optimizing the magnitude of each component force and avoiding individual component forces from being too large or too small. In engineering practice, a reasonable supplementary constraint condition can be introduced (for example, to make Fy1 and Fy2 satisfy a certain proportional relationship, or to make the resultant force of each component force the minimum, etc.) to uniquely determine the solution, or the solution can be directly allocated based on engineering design experience and then substituted for verification.

[0032] After determining the values ​​of Fy1, Fy2, Fy3, and Fy4, in actual loading implementation, considering that Fy1 and Fy2 are both positive forces on the Y-axis, and Fy3 and Fy4 are both negative forces on the Y-axis, if their force application points on the structure can be linked through a linkage or lever mechanism, then the force values ​​of Fy1 and Fy2 can be algebraically combined and output by one actuator; the force values ​​of Fy3 and Fy4 can be algebraically combined and output by another actuator. In this way, only two actuators are needed to complete the joint loading of the three load components Fy, Mx, and Mz. Even without merging, through a clever lever design, only two power sources are needed to drive the four force application points.

[0033] Step 3: Joint decomposition and application of normal force Fz and bending moment My The application requirements of the two target loads, the normal force Fz and the bending moment My about the Y-axis, are considered together. For example... Figure 2 As shown in (a), the target loads are the normal force Fz along the Z-axis and the bending moment My about the Y-axis. Figure 2 As shown in (c), this invention designs two Z-axis (normal) loading points on the mounting edge transition section, applying a first normal component force Fz1 and a second normal component force Fz2 to the load, respectively. Let the loading direction of Fz2 be the positive (or negative) Z-axis, and the direction of Fz1 be the opposite. By manually selecting the coordinate positions of the two loading points in the X-axis direction, the lever arm lengths of each relative to the coordinate origin are determined: let the lever arm length of Fz1 in the X-axis direction be a1, and the lever arm length of Fz2 in the X-axis direction be a2.

[0034] Therefore, a set of mechanical equilibrium equations can be established, which satisfy the two target load components by these two component forces: Fz = Fz2 - Fz1…………(Equation 4; In this embodiment, Fz2 is set to be along the positive Z-axis and Fz1 to be along the negative Z-axis. Therefore, when synthesizing the target value Fz, the configuration of the minus sign in the equation needs to be determined according to the actual direction of Fz. If the target Fz is negative, the equation is written as Fz = Fz2 - Fz1, where Fz2 is positive and Fz1 is negative, and the actual resultant force direction is consistent with the larger force.

[0035] The bending moment My about the Y-axis is formed by the difference in moment produced by the different lever arms of Fz1 and Fz2 in the X-axis direction: My = Fz1×a1 - Fz2×a2…………(Equation 5) In the above system of equations, the target loads Fz and My are known quantities, and the lever arm lengths a1 and a2 can be reasonably selected based on the geometric dimensions of the installation edge and the design space of the transition section. After selecting the lever arm lengths, the two equations contain two unknowns, Fz1 and Fz2. Solving them simultaneously yields the unique solution for each component force. The two forces are applied by two actuators respectively, therefore, this step only requires two actuators to complete the joint loading of Fz and My.

[0036] Step 4: Overall Integration of Load Application Scheme Combining steps one through three above, to apply all six load components to a typical installation edge, the required number of actuators is as follows: 2 actuators for applying axial force Fx; 2 actuators for applying lateral force Fy, bending moment Mx, and torque Mz together; and 2 actuators for applying normal force Fz and bending moment My together. A total of 6 actuators are needed. Compared to the traditional item-by-item loading method, this reduces the number of actuators by an order of magnitude, fundamentally solving the interference problem caused by limited test space. Furthermore, the decomposition scheme of each step ensures no additional torque is generated at the design level, guaranteeing the accuracy of load application.

[0037] Application example: The following section uses the load decomposition method proposed in this invention to illustrate its design steps and engineering implementation in detail with a specific embodiment.

[0038] This embodiment uses the front mounting edge A of the intermediate casing of a certain type of aero-engine as the test object. The target six-component load values ​​of this mounting edge under a typical extreme condition given in the test task specification are shown in Table 1.

[0039] Table 1. Typical load on mounting edge A of the casing According to the load decomposition method of the present invention, the load decomposition scheme is designed according to the following steps: First, design a rigid transition section.

[0040] Based on the structural form and flange interface dimensions of mounting edge A, a matching rigid transition section is designed. The function of this transition section is to transfer the concentrated force applied by the actuator to the corresponding position on the mounting edge. Multiple loading heads (load application interfaces) need to be machined onto the transition section, and the spatial coordinates of each loading head are determined based on the subsequent selection of the lever arm length. Figure 3 The layout of the transition section and loading head is shown.

[0041] Second, determine the lever arm length of each decomposed force.

[0042] A spatial rectangular coordinate system is established with the center position of the A mounting edge as the origin. Based on the outer dimensions of the mounting edge flange and the structural strength requirements of the transition section, the parameters of each lever arm are reasonably selected. The selection of lever arm parameters should follow the following principles: (1) The loading point should be located near the bolt hole distribution circle of the mounting edge flange or at the position of the reinforcing rib of the transition section to ensure uniform load transmission; (2) The lever arm length should not be too small, otherwise it will lead to excessive component force value, and vice versa, it will lead to excessively small component force value, both of which are not conducive to the selection and precise control of the actuator; (3) Sufficient space should be left between different loading points to avoid the actuator and its connecting parts. In this embodiment, the lever arm parameters selected after comprehensive consideration are: a1=150mm, a2=450mm, b2=320mm. The values ​​of c1 and c2 are determined according to the X coordinates of each loading point in Table 2 (which can be deduced from the coordinates of the loading points).

[0043] Third, the axial force Fx is decomposed.

[0044] The target axial force Fx = 31831.8 N is decomposed into two equal components, Fx1 and Fx2. That is, Fx1 = Fx2 = 31831.8 / 2 = 15915.9 N. The loading points of the two components are arranged symmetrically about the origin of the coordinate system, for example, at +420 mm and -420 mm respectively in the Y-axis direction (symmetrical arrangement).

[0045] Fourth, the normal force Fz and bending moment My are jointly decomposed.

[0046] Substitute the target normal force Fz = 17093.2 N and the target bending moment My = -8038.0 N·m into equations (4) and (5) for solution. Assume Fz2 is along the positive Z-axis and Fz1 is along the negative Z-axis. Lever arms a1 = 0.15 m and a2 = 0.45 m. Establish the equations: 17093.2 = Fz2 - Fz1; -8038.0 = Fz1 × 0.15 - Fz2 × 0.45; Solving the above system of equations simultaneously, we obtain Fz2 = 18246.7 N and Fz1 = 1153.4 N. Since the direction of Fz1 is set to the negative Z-axis, its force value is negative, i.e., Fz1 = -1153.4 N. Fz2 is in the positive Z-axis direction, so its force value is positive, i.e., Fz2 = 18246.7 N.

[0047] Fifth, the lateral force Fy, bending moment Mx, and torque Mz are jointly decomposed.

[0048] Substituting the target lateral force Fy = 4883.8 N, the target bending moment Mx = -20295.4 N·m, and the target torque Mz = 2256.7 N·m into equations (1), (2), and (3) for solution. The lever arm b2 = 0.32 m. Based on the coordinates of each loading point determined in Table 2, the X-axis lever arm c1 = 0.1 m for Fy2 and Fy4, and the X-axis lever arm c2 = 0.4 m for Fy1 and Fy3. Establish the equation system: 4883.8 = (Fy1 + Fy2) - (Fy3 + Fy4); -20295.4=(Fy1+Fy2)×0.32+(Fy3+Fy4)×0.32; 2256.7=(Fy2-Fy4)×0.1+(Fy1+Fy3)×0.4; From the second equation, the resultant force relationship can be obtained first: Let S1 = Fy1 + Fy2, S2 = Fy3 + Fy4. Then Fy = S1 - S2 = 4883.8 N, Mx = (S1 + S2) × 0.32 = -20295.4 N·m. Solving the Mx equation, we get S1 + S2 = -20295.4 / 0.32 = -63423.125 N. Combining S1 - S2 = 4883.8 N, we can solve for S1 = -29269.66 N and S2 = -34153.46 N. The negative sign indicates that the direction of the resultant force of this group of forces is opposite to the preset positive direction. Further combining with the third equation, considering a reasonable force value distribution (for example, letting Fy2 and Fy4 satisfy a certain proportional relationship, or coordinating the distribution according to the position of the loading head), we obtain the component force values ​​shown in Table 2. Sixth, summarize and form a load decomposition result table.

[0049] The spatial coordinates of each loading point and the corresponding force components determined by the above calculations are summarized in Table 2.

[0050] Table 2 A. Load Decomposition at Installation Edge Seventh, determine the actuator configuration scheme.

[0051] Based on the decomposition results in Table 2, the final actuator configuration scheme can be determined as follows: (1) Application of axial force Fx: Two actuators are used and connected to the X-direction loading heads numbered Fx1 and Fx2 respectively.

[0052] (2) Application of normal force Fz and bending moment My: Two actuators are used and connected to the Z-direction loading heads numbered FZ2 and FZ1 respectively.

[0053] (3) Application of lateral force Fy, bending moment Mx, and torque Mz: Two actuators are used. One actuator is connected to both the Y-axis loading heads numbered FY1 and FY2 via a lever or connecting mechanism, outputting the resultant force of these two points (19860.1N + 16407.5N); the other actuator is connected to both the Y-axis loading heads numbered FY3 and FY4, outputting the resultant force of these two points (-13965.6N + (-17418.2N)). Thus, a total of two actuators are used for loading the Fy group.

[0054] A total of six actuators are needed to accurately apply all six components of the load on mounting edge A. The spatial layout of the application scheme is as follows: Figure 3 As shown. By Figure 3 It can be clearly seen that the arrangement of the six actuators around the intermediate housing is very simple, with sufficient gaps between them, completely avoiding the problem of spatial geometric interference, and the scheme has good engineering feasibility.

[0055] As can be clearly seen from the above embodiments, the load decomposition method for the strength test of the intermediate casing of an aero-engine proposed in this invention successfully and rationally decomposes all components of the complex load borne by a single mounting edge, achieving high-precision loading with a very small number of actuators. This method is not limited to the specific values ​​in this embodiment. Regardless of how the magnitude and direction of the forces Fx, Fy, Fz and the moments Mx, My, Mz borne by the mounting edge change, this method can complete the load decomposition by adjusting the lever arm parameters and the values ​​of each component force, meeting the testing requirements of multi-axis loads formed by different combinations of maneuvering and aerodynamic loads. Therefore, adopting the load decomposition method of this invention will greatly reduce the workload of load decomposition and the difficulty of test implementation, significantly reduce the number of actuators used, avoid spatial interference, eliminate additional moments, and has significant economic value and broad engineering application prospects.

[0056] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for decomposing the test load of an intermediate casing for strength testing of an aero-engine, characterized in that, Includes the following steps: S1: A rigid transition section is fitted on the mounting edge of the intermediate casing to be tested, and several loading heads with defined spatial coordinate positions are constructed on the transition section; S2: Decompose the target axial force Fx into a first axial component Fx1 and a second axial component Fx2. Fx1 and Fx2 are equal in magnitude and have the same direction. Their points of application are symmetrically arranged with respect to the coordinate origin of the mounting edge. They are applied through two actuators respectively. S3: The target lateral force Fy, target bending moment Mx, and target torque Mz are jointly decomposed into the first lateral component Fy1, the second lateral component Fy2, the third lateral component Fy3, and the fourth lateral component Fy4. Using the preset lever arm length, a set of force and torque balance equations satisfying Fy, Mx, and Mz by Fy1, Fy2, Fy3, and Fy4 are established to solve for the value of each component force, and the loading is completed by only two actuators. S4: Decompose the target normal force Fz and the target bending moment My into the first normal component force Fz1 and the second normal component force Fz2. Using the preset lever arm length, establish a set of force and moment balance equations that satisfy Fz and My with Fz1 and Fz2 to solve for the values ​​of each component force, and complete the loading through only two actuators.

2. The method for decomposing the test load of the intermediate casing of an aero-engine according to claim 1, characterized in that, In step S2, the equations Fx = Fx1 + Fx2 and Fx1 = Fx2 are satisfied, so that the resultant force passes through the origin of the coordinate system and does not generate additional bending moment or torque.

3. The method for decomposing the test load of the intermediate casing of an aero-engine according to claim 1, characterized in that, In step S3, the force and torque balance equations are as follows: Fy=(Fy1+Fy2)-(Fy3+Fy4), Mx=(Fy1+Fy2)×b2+(Fy3+Fy4)×b2; Mz=(Fy2-Fy4)×c1+(Fy1+Fy3)×c2; Where b2 is the lever arm length of each component force in the Z-axis direction, and c1 and c2 are the lever arm lengths of different component forces in the X-axis direction.

4. The method for decomposing the test load of the intermediate casing of an aero-engine according to claim 1 or 3, characterized in that, In step S3, the component forces with the same direction are algebraically combined, and the combined force is output through an actuator.

5. The method for decomposing the test load of the intermediate casing of an aero-engine according to claim 1, characterized in that, In step S4, the force and torque balance equations are as follows: Fz = Fz2 - Fz1; My = Fz1×a1 - Fz2×a2. Where a1 is the lever arm length of Fz1 in the X-axis direction, and a2 is the lever arm length of Fz2 in the X-axis direction.

6. The method for decomposing the test load of the intermediate casing of an aero-engine according to claim 1, characterized in that, In step S4, the force and moment balance equations are: the load borne by the mounting edge consists of six components in an orthogonal coordinate system: axial force Fx, lateral force Fy, normal force Fz, bending moment Mx, bending moment My, and torque Mz.

7. The method for decomposing the test load of the intermediate casing of an aero-engine according to claim 1, characterized in that, In steps S2, S3, and S4, the actuating cylinders are all connected to the loading heads at the corresponding coordinates on the rigid transition section to apply the decomposed component forces.

8. The method for decomposing the test load of the intermediate casing of an aero-engine according to claim 1, characterized in that, The method reduces the total number of actuators required for one mounting edge of the intermediate housing to six by using an adapter section adapted to the mounting edge.

9. A loading system for a strength test load of an aero-engine intermediate casing, characterized in that, The method for disassembling the test load of the intermediate casing of an aero-engine as described in any one of claims 1 to 18, the system comprising: A rigid adapter section is used to secure it to the mounting edge of the intermediate housing to be tested; At least six actuators are connected to loading heads at pre-set coordinate positions on the rigid transition section; The control system is used to control the actuator to load according to the decomposed force values, so as to jointly simulate the six-component load of the target.

10. The loading system for the strength test load of an aero-engine intermediate casing according to claim 9, characterized in that, Of the six actuators, two are used to apply the first axial component force Fx1 and the second axial component force Fx2 after decomposition; and two are used to apply the first normal component force Fz1 and the second normal component force Fz2 after decomposition. A resultant force for applying the first lateral component Fy1 and the second lateral component Fy2; A resultant force used to apply the third lateral component Fy3 and the fourth lateral component Fy4.

Images