A design method and system for topological optimization of an intermediate casing of an aeroengine

Abstract

The present invention relates to the technical field of aero-engine structure design and manufacturing, and discloses a topology optimization structure design method and system for an aero-engine intermediate casing. By accurately capturing the mechanical responses of the intermediate casing under different working conditions and using these mechanical parameters as inputs, a finite element analysis is performed on the initial model of the intermediate casing to obtain the initial compliance and compliance weight coefficient of the intermediate casing under each assessment working condition; finally, taking the artificial pseudo-density of the intermediate casing analysis model as the design variable and taking the axial force, torque, flow passage cavity pressure, and inner ring wall plate inner bearing cavity pressure under each assessment working condition as inputs, under the condition of satisfying the preset volume fraction ratio constraint of the intermediate casing, the minimization of the weighted compliance of the intermediate casing is realized, thereby obtaining the topology optimization configuration of the intermediate casing, and significantly reducing the casing structure weight on the basis of ensuring the strength and stiffness of the intermediate casing.

Description

Technical Field

[0001] The present invention relates to the technical field of aero-engine structure design and manufacturing, and discloses a topological optimization structure design method and system for an aero-engine intermediate case. Background Art

[0002] The intermediate case is the main load-bearing frame of the engine, and at the same time is the overall design and assembly reference of the engine. It transmits thrust, torque, etc. to the aircraft, and at the same time undertakes functions such as connecting the fan and the compressor, installing accessories, and bleeding air from the air system. The service loads mainly include chamber pressure, high temperature, and the thrust and torque of the engine, as well as large maneuvering overloads, vibrations, etc.

[0003] The intermediate case is large in size, thin in wall, and complex in structure. Generally, six to eight hollow struts connect the outer ring wall plate, the splitter ring, and the inner ring wall plate into a whole. There are multiple mounting bosses on the ring surface, and the struts are usually semi-closed cavity structures. The inner surface of the outer ring wall plate and the outer surface of the splitter ring form the initial section of the outer bypass duct of the engine, and the inner surface of the splitter ring and the outer surface of the inner ring wall plate form the inner main flow passage of the engine.

[0004] The intermediate case is a key part in an aero-engine, and it has an important influence on the performance, life, and reliability of the engine. The intermediate case parts need to have high strength and stiffness, and at the same time reduce the weight as much as possible.

[0005] The traditional intermediate case is formed by titanium alloy casting + welding or integral precision casting. Due to the limitations of the casting and welding forming methods, the wall thickness of the intermediate case is relatively thick (controlled above 3 mm), and the castings usually have problems such as large dimensional deformation, overweight structure, and long manufacturing cycle. Summary of the Invention

[0006] The purpose of the present invention is to provide a topological optimization structure design method and system for an aero-engine intermediate case, which can minimize the weighted compliance of the intermediate case under the condition of meeting the preset volume fraction constraint of the intermediate case, so as to obtain the topological optimization configuration of the intermediate case, and significantly reduce the weight of the case structure on the basis of ensuring the strength and stiffness of the intermediate case.

[0007] In order to achieve the above technical effects, the technical solution adopted by the present invention is:

[0008] A topological optimization structure design method for an aero-engine intermediate case, comprising:

[0009] According to the design structure and aerodynamic shape of the intermediate casing, an initial model of the intermediate casing is obtained; the initial model includes the outer ring wall plate, the splitter ring, the inner ring wall plate and the load-bearing support plate of the intermediate casing; the splitter ring is coaxially arranged in the flow passage formed by the inner ring wall plate and the outer ring wall plate and is used to divide the flow passage of the intermediate casing into an outer flow passage and an inner flow passage; the load-bearing support plate is arranged in the flow passage formed by the inner ring wall plate and the outer ring wall plate along the radial direction of the intermediate casing, and an inner ring bracket for cooperating and connecting with the bearing chamber housing is arranged on the inner ring wall plate.

[0010] The finite element analysis method is used to simulate and analyze the initial model to obtain the axial force, torque, flow passage cavity pressure and bearing cavity pressure on the inner side of the inner ring wall plate of the intermediate casing under multiple evaluation conditions.

[0011] Taking the axial force, torque, flow passage cavity pressure and bearing cavity pressure on the inner side of the inner ring wall plate under each evaluation condition as inputs, the initial compliance of the intermediate casing under each evaluation condition is obtained by simulating and analyzing the initial model.

[0012] According to the ratio of the axial force under each evaluation condition to the axial force of the intermediate casing under the design point condition, the initial compliance of the intermediate casing under each evaluation condition is corrected to obtain the compliance correction value corresponding to the evaluation condition.

[0013] According to the compliance correction values under all evaluation conditions, the compliance weight coefficient of each evaluation condition is analyzed and obtained.

[0014] Taking the artificial pseudo-density of the intermediate casing analysis model as the design variable, taking the axial force, torque, flow passage cavity pressure and bearing cavity pressure on the inner side of the inner ring wall plate under each evaluation condition as inputs, taking the volume fraction of the intermediate casing not being greater than the preset volume fraction ratio as the constraint condition, and taking the minimum weighted compliance of the intermediate casing under all evaluation conditions as the design goal, the topology optimization of the analysis model is carried out to obtain the topology optimization configuration of the intermediate casing.

[0015] Furthermore, the surface fitting method is used to reconstruct the model after topology optimization to make the structure of the intermediate casing smooth and continuous.

[0016] Furthermore, an installation seat for fixing the intermediate casing is arranged on the outer wall surface of the outer ring wall plate of the intermediate casing, and a homogeneous cubic lattice with equal rod diameters is used to fill the lattice in the circumferential area of the installation seat. The range of the lattice filling area is the area between the outer edge of the installation seat and the stiffener closest to the outer edge of the installation seat, and the filling depth is not greater than 1 / 2 of the casing wall thickness, forming a lattice + skeleton structure.

[0017] Further, the preset volume fraction ratio of the intermediate casing is as follows: the volume fraction within the lower wall surface of the inner ring wall plate is not greater than the first preset volume fraction ratio, and the volume fraction ratio of the remaining design domain is not greater than the second preset volume fraction ratio.

[0018] Further, the weighted compliance of the intermediate casing under all assessment conditions , where , is the total number of assessment conditions, is the compliance weight coefficient of the th assessment condition, ; is the compliance correction value of the th assessment condition, , is the initial compliance of the th assessment condition obtained by simulation, is the structure factor, The value range is 0.8 - 1.5, is the axial force of the intermediate casing under the design point condition, is the th axial force of the intermediate casing under the assessment condition.

[0019] To achieve the above technical effects, the present invention also provides a topology optimization structure design system for an aeroengine intermediate casing, including:

[0020] A model construction module, configured to obtain the initial model of the intermediate casing according to the design structure and aerodynamic styling of the intermediate casing; the initial model includes the outer ring wall plate, the splitter ring, the inner ring wall plate, and the load-bearing support plate of the intermediate casing; the splitter ring is coaxially arranged in the flow channel formed by the inner ring wall plate and the outer ring wall plate, and is used to divide the flow channel of the intermediate casing into an outer flow channel and an inner flow channel; the load-bearing support plate is radially arranged in the flow channel formed by the inner ring wall plate and the outer ring wall plate, and the inner ring wall plate is provided with an inner ring bracket for cooperating and connecting with the bearing chamber housing;

[0021] A simulation analysis module, configured to perform simulation analysis on the initial model by using the finite element analysis method to obtain the axial force, torque, flow channel cavity pressure, and inner ring wall plate inner side bearing cavity pressure of the intermediate casing under multiple assessment conditions;

[0022] A compliance analysis module, configured to take the axial force, torque, flow channel cavity pressure, and inner ring wall plate inner side bearing cavity pressure under each assessment condition as inputs, perform simulation analysis on the initial model, and obtain the initial compliance of the intermediate casing under each assessment condition;

[0023] A flexibility correction module is used to correct the initial flexibility of the intermediate casing under each assessment condition according to the ratio of the axial force under each assessment condition to the axial force of the intermediate casing under the design point condition, so as to obtain the flexibility correction value corresponding to each assessment condition;

[0024] A weight coefficient analysis module is used to analyze and obtain the flexibility weight coefficient of each assessment condition according to the flexibility correction values under all assessment conditions;

[0025] A topology optimization module is used to take the artificial pseudo-density of the intermediate casing analysis model as the design variable, take the axial force, torque, flow passage cavity pressure, and inner ring wall plate inner bearing cavity pressure under each assessment condition as inputs, take the volume fraction of the intermediate casing not being greater than the preset volume fraction ratio as the constraint condition, and take the minimum weighted flexibility of the intermediate casing under all assessment conditions as the design goal to perform topology optimization on the analysis model, so as to obtain the topology optimization configuration of the intermediate casing.

[0026] Further, it further includes a model reconstruction module, which is used to reconstruct the topologically optimized model by using the surface fitting method, so that the structure of the intermediate casing is smooth and continuous.

[0027] Further, it further includes a lattice filling module, which is used to set a mounting seat for fixing the intermediate casing according to the outer wall surface of the outer ring wall plate of the intermediate casing, and fill the lattice in the circumferential area of the mounting seat by using a homogeneous system cubic lattice with equal rod diameters. The lattice filling area range is the area between the outer edge of the mounting seat and the stiffener closest to the outer edge of the mounting seat, and the filling depth is not greater than 1 / 2 of the casing wall thickness, so as to form a lattice + skeleton structure.

[0028] Further, in the topology optimization module, the preset volume fraction ratio of the intermediate casing is: the volume fraction within the lower wall surface of the inner ring wall plate is not greater than the first preset volume fraction ratio, and the volume fraction ratio of the remaining part of the design domain is not greater than the second preset volume fraction ratio.

[0029] Further, in the topology optimization module, the weighted flexibility of the intermediate casing under all assessment conditions , where , is the total number of assessment conditions, is the flexibility weight coefficient of the th assessment condition, ; is the flexibility correction value of the th assessment condition, , is the initial flexibility of the th assessment condition obtained by simulation, is the structure factor, The value range is 0.8 to 1.5, which is the axial force of the intermediate casing under the design point operating condition, and is the axial force of the intermediate casing under the

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows: By accurately capturing the mechanical responses of the intermediate casing under different operating conditions and using these mechanical parameters as inputs, a finite element analysis is performed on the initial model of the intermediate casing to obtain the initial compliance and compliance weight coefficient of the intermediate casing under each test operating condition; Finally, taking the artificial pseudo-density of the intermediate casing analysis model as the design variable and taking the axial force, torque, flow passage cavity pressure, and inner ring wall plate inner bearing cavity pressure under each test operating condition as inputs, under the condition of satisfying the preset volume fraction ratio constraint of the intermediate casing, the minimization of the weighted compliance of the intermediate casing is achieved, thereby obtaining the topology optimization configuration of the intermediate casing, and significantly reducing the structural weight of the casing while ensuring the strength and stiffness of the intermediate casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is the flow chart of the topology optimization structural design method for the intermediate casing of an aeroengine in Embodiment 1;

[0032] Figure 2 is the structural schematic diagram of the intermediate casing in Embodiment 1 or 2;

[0033] Figure 3 is the structural block diagram of the topology optimization structural design system for the intermediate casing of an aeroengine in Embodiment 1;

[0034] Figure 4 is the flow chart of the topology optimization structural design method for the intermediate casing of an aeroengine in Embodiment 2;

[0035] Figure 5 is the structural schematic diagram of the stiffening rib and lattice filling area in Embodiment 1 or 2;

[0036] Wherein, 1, outer ring wall plate; 2, splitter ring; 3, inner ring wall plate; 4, load-bearing support plate; 5, outer flow passage; 6, inner flow passage; 7, inner ring bracket; 8, mounting seat; 9, stiffening rib; 10, model construction module; 11, simulation analysis module; 12, compliance analysis module; 13, compliance correction module; 14, weight coefficient analysis module; 15, topology optimization module; 16, model reconstruction module; 17, lattice filling module; 18, lattice filling area. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] The present invention will be further described in detail below in conjunction with embodiments and the accompanying drawings. However, it should not be understood that the scope of the above-mentioned subject matter of the present invention is limited to the following embodiments. Any technology implemented based on the content of the present invention belongs to the scope of the present invention.

[0038] Embodiment 1

[0039] Refer to Figure 1 、 Figure 2 、 Figure 3 and Figure 5 , a topological optimization structure design method for an intermediate casing of an aeroengine, comprising:

[0040] According to the design structure and aerodynamic styling of the intermediate casing, an initial model of the intermediate casing is obtained; the initial model includes an outer ring wall plate 1, a splitter ring 2, an inner ring wall plate 3, and a load-bearing support plate 4 of the intermediate casing; the splitter ring 2 is coaxially arranged in the flow passage formed by the inner ring wall plate 3 and the outer ring wall plate 1 for dividing the flow passage of the intermediate casing into an outer flow passage 5 and an inner flow passage 6; the load-bearing support plate 4 is arranged radially in the flow passage formed by the inner ring wall plate 3 and the outer ring wall plate 1, and an inner ring bracket 7 for cooperating and connecting with a bearing chamber housing is arranged on the inner ring wall plate 3;

[0041] The initial model is simulated and analyzed by using the finite element analysis method to obtain the axial force, torque, flow passage cavity pressure, and the bearing chamber pressure on the inner side of the inner ring wall plate 3 of the intermediate casing under multiple assessment conditions;

[0042] Taking the axial force, torque, flow passage cavity pressure, and the bearing chamber pressure on the inner side of the inner ring wall plate 3 under each assessment condition as inputs, the initial model is simulated and analyzed to obtain the initial compliance of the intermediate casing under each assessment condition;

[0043] According to the ratio of the axial force under each assessment condition to the axial force of the intermediate casing under the design point condition, the initial compliance of the intermediate casing under each assessment condition is corrected to obtain the compliance correction value corresponding to the assessment condition;

[0044] According to the compliance correction values under all assessment conditions, the compliance weight coefficient of each assessment condition is analyzed and obtained;

[0045] Taking the artificial pseudo-density of the intermediate casing analysis model as the design variable, taking the axial force, torque, flow passage cavity pressure, and the bearing chamber pressure on the inner side of the inner ring wall plate 3 under each assessment condition as inputs, taking the volume fraction of the intermediate casing not being greater than a preset volume fraction ratio as the constraint condition, and taking the minimum weighted compliance of the intermediate casing under all assessment conditions as the design goal, the analysis model is topologically optimized to obtain the topological optimization configuration of the intermediate casing.

[0046] In this embodiment, the axial force, torque, flow passage cavity pressure, and inner ring wall plate 3 inner bearing cavity pressure of the intermediate casing under multiple assessment conditions are obtained through simulation, accurately capturing the mechanical response of the intermediate casing under different conditions. Using these mechanical parameters as inputs, a finite element analysis is performed on the initial model of the intermediate casing to obtain the initial compliance of the intermediate casing under each assessment condition. Then, a fatigue correction coefficient conversion is performed using the axial force that affects the low-cycle fatigue load to correct the initial compliance of each assessment condition and obtain the corresponding compliance correction value. The compliance weight coefficient under each assessment condition is obtained by normalizing the compliance correction value. Finally, with the artificial pseudo-density of the intermediate casing analysis model as the design variable and the axial force, torque, flow passage cavity pressure, and inner ring wall plate 3 inner bearing cavity pressure under each assessment condition as inputs, under the condition of satisfying the preset volume fraction ratio constraint of the intermediate casing, the weighted compliance of the intermediate casing is minimized, thereby obtaining the topology optimization configuration of the intermediate casing, significantly reducing the casing structure weight while ensuring the strength and stiffness of the intermediate casing.

[0047] Based on the same inventive concept, this embodiment also provides an aero-engine intermediate casing topology optimization structural design system, including:

[0048] A model construction module 10, configured to obtain the initial model of the intermediate casing according to the intermediate casing design structure and aerodynamic styling; the initial model includes an outer ring wall plate 1, a splitter ring 2, an inner ring wall plate 3, and a load-bearing support plate 4 of the intermediate casing; the splitter ring 2 is coaxially arranged in the flow passage formed by the inner ring wall plate 3 and the outer ring wall plate 1 for dividing the flow passage of the intermediate casing into an outer flow passage 5 and an inner flow passage 6; the load-bearing support plate 4 is arranged in the flow passage formed by the inner ring wall plate 3 and the outer ring wall plate 1 along the radial direction of the intermediate casing, and the inner ring wall plate 3 is provided with an inner ring bracket 7 for mating connection with the bearing cavity housing;

[0049] A simulation analysis module 11, configured to perform a simulation analysis on the initial model by using a finite element analysis method to obtain the axial force, torque, flow passage cavity pressure, and inner ring wall plate 3 inner bearing cavity pressure of the intermediate casing under multiple assessment conditions;

[0050] A compliance analysis module 12, configured to perform a simulation analysis on the initial model with the axial force, torque, flow passage cavity pressure, and inner ring wall plate 3 inner bearing cavity pressure under each assessment condition as inputs to obtain the initial compliance of the intermediate casing under each assessment condition;

[0051] A compliance correction module 13, configured to correct the initial compliance of the intermediate casing under each assessment condition according to the ratio of the axial force under each assessment condition to the axial force of the intermediate casing under the design point condition to obtain the compliance correction value corresponding to the assessment condition;

[0052] A weight coefficient analysis module 14, configured to analyze and obtain the compliance weight coefficient of each assessment condition according to the compliance correction values under all assessment conditions;

[0053] A topology optimization module 15, configured to use the artificial pseudo-density of the intermediate casing analysis model as a design variable, use the axial force, torque, flow passage cavity pressure, and inner ring wall 3 inner bearing cavity pressure under each assessment condition as inputs, and use the condition that the volume fraction of the intermediate casing is not greater than a preset volume fraction ratio as a constraint condition, and perform topology optimization on the analysis model with the minimum weighted compliance of the intermediate casing under all assessment conditions as the design goal to obtain the topology optimization configuration of the intermediate casing.

[0054] In this embodiment, it further includes a model reconstruction module 16, configured to reconstruct the topologically optimized model by using the surface fitting method, so that the intermediate casing structure is smooth and continuous.

[0055] In this embodiment, it further includes a lattice filling module 17, configured to set a mounting seat 8 for fixing the intermediate casing according to the outer wall surface of the outer ring wall 1 of the intermediate casing, fill the lattice in the circumferential area of the mounting seat 8 with a homogeneous cubic lattice with equal rod diameters, and the lattice filling area 18 ranges from the outer edge of the mounting seat 8 to the area between the outer edge of the mounting seat 8 and the nearest stiffener 9. Among them, no lattice is filled between the mounting seat 8 and the intermediate casing mounting edge, and the filling depth is not greater than 1 / 2 of the casing wall thickness, forming a lattice + skeleton structure.

[0056] Embodiment 2

[0057] See Figure 2 、 Figure 4 and Figure 5 , taking the structural design of the intermediate casing of a certain type of aero-engine as an example, this embodiment details the process of the topology optimization structural design method of the aero-engine intermediate casing of the present invention. The intermediate casing is made of TA15 titanium alloy material, and the specific design steps are as follows:

[0058] Step 1: Obtain the initial model of the intermediate casing according to the intermediate casing design structure and aerodynamic styling; the initial model includes the outer ring wall 1, the splitter ring 2, the inner ring wall 3, and the load-bearing support plate 4 of the intermediate casing; the splitter ring 2 is coaxially arranged in the flow passage formed by the inner ring wall 3 and the outer ring wall 1, and is used to divide the flow passage of the intermediate casing into an outer flow passage 5 and an inner flow passage 6; the load-bearing support plate 4 is arranged in the flow passage formed by the inner ring wall 3 and the outer ring wall 1 along the radial direction of the intermediate casing, and the inner ring wall 3 is provided with an inner ring bracket 7 for mating and connecting with the bearing cavity housing.

[0059] In this embodiment, the typical structure of the intermediate casing is as Figure 2As shown. According to the differences in force and function, the outer ring wall plate 1 of the intermediate casing, the flow dividing ring 2, the inner ring wall plate 3, and the load-bearing support plate 4 are disassembled. Using the tetrahedral elements of the finite element software Hypermesh, the three-dimensional geometric entity models of the disassembled parts are meshed; in this embodiment, the tetrahedral unit size is set to 2 mm.

[0060] Then, the material properties of TA15 titanium alloy are assigned to the optimized design area. The material properties mainly include elastic modulus, density, Poisson's ratio, etc. at different temperatures.

[0061] Step 2: Use the finite element analysis method to simulate and analyze the initial model to obtain the axial force, torque, flow passage cavity pressure, and inner bearing cavity pressure of the inner ring wall plate 3 of the intermediate casing under multiple assessment conditions; where:

[0062] a) Flow passage cavity pressure: Applied on the surface of the inner flow passage 6 of the outer ring wall plate 1, the inner and outer wall surfaces of the flow dividing ring 2, and the outer flow passage 5 surface of the inner ring wall plate 3;

[0063] b) Bearing cavity pressure: Applied on the inner surface of the inner ring wall plate 3;

[0064] c) Axial force: The axial force acts on the mounting edge; to ensure the uniformity of loading, all loading nodes are coupled together, and the rbe3 element in Hypermesh is used to load the cross-section. Select all nodes on the mounting edge as the master nodes, the calculation nodes as the slave nodes, generate the rbe3 element, and apply the axial force (unit: N) on this rbe3 element;

[0065] d) Torque: The torque acts on the mounting edge; with the engine axis as the X-axis, the intersection of the main mounting plane and the axis as the coordinate origin, and the counterclockwise direction as positive.

[0066] Step 3: Using the axial force, torque, flow passage cavity pressure, and inner bearing cavity pressure of the inner ring wall plate 3 under each assessment condition as inputs, simulate and analyze the initial model to obtain the initial compliance of the intermediate casing under each assessment condition.

[0067] Step 4: According to the ratio of the axial force under each assessment condition to the axial force of the intermediate casing under the design point condition, correct the initial compliance of the intermediate casing under each assessment condition to obtain the compliance correction value corresponding to the assessment condition;

[0068] In this embodiment, the compliance correction value of the th assessment condition , where is the total number of assessment conditions, is the initial compliance of the th assessment condition obtained by simulation in Step 3, is the structure factor, and its value range is 0.8 to 1.5, is the axial force of the intermediate casing under the design point condition, is the axial force of the intermediate casing under the

[0069] Step Five: Analyze and obtain the compliance weight coefficient for each assessment condition according to the compliance correction values under all assessment conditions;

[0070] In this embodiment, the compliance weight coefficient of the th assessment condition .

[0071] Step Six: Using the artificial pseudo-density of the intermediate casing analysis model as the design variable, with the axial force, torque, flow passage cavity pressure, and inner ring wall 3 inner bearing cavity pressure under each assessment condition as inputs, and with the volume fraction of the intermediate casing not exceeding the preset volume fraction ratio as the constraint condition, and with the weighted compliance of the intermediate casing under all assessment conditions being minimized as the design objective, perform topology optimization on the analysis model to obtain the topology optimization configuration of the intermediate casing;

[0072] In this embodiment, the artificial pseudo-density of the material in the design unit is used as the design variable, and the overall compliance of the intermediate casing is minimized as the optimization objective, that is, the objective function of the topology optimization is ; where ;

[0073] Then, apply the constraint conditions of the topology optimization design, mainly including: taking the volume fraction of each design domain as the optimization constraint, with the volume fraction within the lower wall surface of the inner ring wall 3 not exceeding the first preset volume fraction ratio, and the volume fraction of the remaining part of the design domain not exceeding the second preset volume fraction ratio; in this embodiment, the first preset volume fraction ratio is taken as 0.2, and the second preset volume fraction ratio is taken as 0.3.

[0074] In addition, the constraint conditions in this embodiment also include:

[0075] Apply periodic cyclic symmetry constraints, and the number of periods is equal to the number of struts;

[0076] Set the minimum size constraint to 8 mm and the maximum size constraint to 16 mm for the upper and lower walls of the inner flow path, the struts in the inner flow path part, and the internal brackets. For the remaining parts, set the minimum size constraint to 6 mm and the maximum size constraint to 12 mm.

[0077] Finally, use the finite element software Hyperworks to complete the topology optimization calculation of the above model.

[0078] Step 7: Reconstruct the topologically optimized model using the surface fitting method to make the intermediate casing structure smooth and continuous;

[0079] In this embodiment, the UG NX software is used to reconstruct the model of the topologically optimized intermediate casing. The surface fitting method is used to reconstruct the topologically optimized model to make the stiffening structure uniform, smooth and continuous. The fillets can also be adjusted at the positions where the fillets are too small after local stiffening, and the fillet is set to be not less than R2.0 mm.

[0080] Step 8: An installation seat 8 for fixing the intermediate casing is provided on the outer wall surface of the outer ring wall plate 1 of the intermediate casing. A homogeneous system cubic lattice with equal rod diameters is used to fill the lattice in the circumferential area of the installation seat 8. The range of the lattice filling area 18 is the area between the outer edge of the installation seat 8 and the stiffening rib 9 closest to the outer edge of the installation seat 8. The filling depth is not greater than 1 / 2 of the casing wall thickness, forming a lattice + skeleton structure;

[0081] In this embodiment, the topological configuration of the intermediate casing is a periodic cyclic symmetric stiffening rib 9 structure, and there are obvious stiffening rib 9 structures on each wall surface (the outer side of the outer ring wall plate 1 or the inner side of the inner ring wall plate 3). The intermediate casing has a large strength reserve in the installation seat 8 area with a relatively low stress level. In this embodiment, according to the force analysis and process constraints, a lattice filling area 18 can be set in the installation seat 8 area, and a homogeneous lattice with equal rod diameters is used for filling. A lattice structure scheme is formed by the shelling method. The lattice is not filled between the installation seat 8 and the installation edge of the intermediate casing, so as to obtain an intermediate casing configuration of "lattice + skeleton", as Figure 5 shown.

[0082] Based on the obtained intermediate casing configuration of "lattice + skeleton" in this embodiment, the finite element software ANSYS is used to analyze the strength of the intermediate casing. The static strength and fatigue life of the intermediate casing meet the design requirements. In addition, the finite element simulation software is used to simulate the additive manufacturing process of the intermediate casing model. Process supports are set at the positions between the stress-concentrated stiffening ribs 9 and the middle of the stiffening ribs 9. Process supports are added between the outer ring wall plate 1, the diverter ring 2, and the inner ring wall plate 3 of the intermediate casing, and process supports are added between the load-bearing support plates 4 to reduce the deformation of the side walls of the part.

[0083] In this embodiment, the laser selective melting additive manufacturing process plan is further used to prepare the intermediate casing. The obtained TA15 titanium alloy intermediate casing with a "lattice + skeleton" structure has a density of the solid part ≥ 99.5% after testing. Its weight is 67.2 Kg, which is 20.0% lighter than the traditional cast intermediate casing (84.0 Kg); and the manufacturing cycle is reduced from 2.5 months of the casting to 1.5 months, shortening the manufacturing cycle.

[0084] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A design method for the topological optimization structure of an aero-engine intermediate casing, characterized in that, Including: Obtaining an initial model of the intermediate casing according to the design structure and aerodynamic shape of the intermediate casing; The initial model includes an outer ring wall plate, a diverter ring, an inner ring wall plate and a load-bearing support plate of the intermediate casing; the diverter ring is coaxially arranged in the flow channel formed by the inner ring wall plate and the outer ring wall plate for dividing the flow channel of the intermediate casing into an outer flow channel and an inner flow channel; the load-bearing support plate is arranged in the flow channel formed by the inner ring wall plate and the outer ring wall plate along the radial direction of the intermediate casing, and the inner ring wall plate is provided with an inner ring bracket for cooperating and connecting with the bearing cavity housing; Performing simulation analysis on the initial model by using a finite element analysis method to obtain the axial force, torque, flow channel cavity pressure and bearing cavity pressure on the inner side of the inner ring wall plate of the intermediate casing under multiple assessment conditions; Taking the axial force, torque, flow channel cavity pressure and bearing cavity pressure on the inner side of the inner ring wall plate under each assessment condition as inputs, performing simulation analysis on the initial model to obtain the initial compliance of the intermediate casing under each assessment condition; Correcting the initial compliance of the intermediate casing under each assessment condition according to the ratio of the axial force under each assessment condition to the axial force of the intermediate casing under the design point condition to obtain a compliance correction value corresponding to the assessment condition; Analyzing and obtaining the compliance weight coefficient of each assessment condition according to the compliance correction values under all assessment conditions; Taking the artificial pseudo-density of the intermediate casing analysis model as a design variable, taking the axial force, torque, flow channel cavity pressure and bearing cavity pressure on the inner side of the inner ring wall plate under each assessment condition as inputs, taking the volume fraction ratio of the intermediate casing not being greater than a preset volume fraction ratio as a constraint condition, and taking the minimum weighted compliance of the intermediate casing under all assessment conditions as a design goal to perform topology optimization on the analysis model to obtain the topology optimization configuration of the intermediate casing.

2. The topological optimization structural design method of the intermediate casing of an aeroengine according to claim 1, wherein Reconstructing the topologically optimized model by using a surface fitting method to make the structure of the intermediate casing smooth and continuous.

3. The topological optimization structural design method of the intermediate casing of an aeroengine according to claim 1, wherein An installation seat for fixing the intermediate casing is arranged on the outer wall surface of the outer ring wall plate of the intermediate casing, and a homogeneous system cubic lattice with an equal rod diameter is used to fill the lattice in the circumferential area of the installation seat. The range of the lattice filling area is the area between the outer edge of the installation seat and the stiffener closest to the outer edge of the installation seat, and the filling depth is not greater than 1 / 2 of the casing wall thickness, forming a lattice + skeleton structure.

4. The topological optimization structural design method of the intermediate casing of an aeroengine according to claim 1, wherein The preset volume fraction ratio of the intermediate casing is: the volume fraction ratio within the lower wall surface of the inner ring wall plate is not greater than the first preset volume fraction ratio, and the volume fraction ratio of the remaining part of the design domain is not greater than the second preset volume fraction ratio.

5. The topological optimization structural design method of the intermediate casing of an aeroengine according to claim 1, characterized in that, The weighted compliance of the intermediate casing under all test conditions , where , is the total number of test conditions, is the compliance weight coefficient of the th test condition, ; is the compliance correction value of the th test condition, , is the initial compliance of the intermediate casing obtained by simulation for the th test condition, is the structure factor, with a value range of 0.8 to 1.5, is the axial force of the intermediate casing under the design point condition, is the axial force of the intermediate casing under the th test condition.

6. A topological optimization structure design system for an aeroengine intermediate case, characterized in that, Including: A model construction module for obtaining an initial model of the intermediate casing according to the design structure and aerodynamic shape of the intermediate casing; The initial model includes an outer ring wall plate, a diverter ring, an inner ring wall plate and a load-bearing support plate of the intermediate casing; the diverter ring is coaxially arranged in the flow channel formed by the inner ring wall plate and the outer ring wall plate for dividing the flow channel of the intermediate casing into an outer flow channel and an inner flow channel; the load-bearing support plate is arranged in the flow channel formed by the inner ring wall plate and the outer ring wall plate along the radial direction of the intermediate casing, and the inner ring wall plate is provided with an inner ring bracket for cooperating and connecting with the bearing cavity housing; The simulation analysis module is used to perform simulation analysis on the initial model by using the finite element analysis method to obtain the axial force, torque, flow passage cavity pressure, and inner ring wall plate inner bearing cavity pressure of the intermediate casing under multiple assessment conditions; The compliance analysis module is used to perform simulation analysis on the initial model with the axial force, torque, flow passage cavity pressure, and inner ring wall plate inner bearing cavity pressure under each assessment condition as inputs to obtain the initial compliance of the intermediate casing under each assessment condition; The compliance correction module is used to correct the initial compliance of the intermediate casing under each assessment condition according to the ratio of the axial force under each assessment condition to the axial force of the intermediate casing under the design point condition to obtain the compliance correction value corresponding to the assessment condition; The weight coefficient analysis module is used to analyze and obtain the compliance weight coefficient of each assessment condition according to the compliance correction values under all assessment conditions; The topology optimization module is used to perform topology optimization on the analysis model with the artificial pseudo-density of the intermediate casing analysis model as the design variable, the axial force, torque, flow passage cavity pressure, and inner ring wall plate inner bearing cavity pressure under each assessment condition as inputs, the volume fraction of the intermediate casing not exceeding the preset volume fraction ratio as the constraint condition, and the minimum weighted compliance of the intermediate casing under all assessment conditions as the design goal to obtain the topology optimization configuration of the intermediate casing.

7. The aero-engine intermediate casing topology optimization structure design system according to claim 6, characterized in that, It further includes a model reconstruction module, which is used to reconstruct the topologically optimized model by using the surface fitting method to make the structure of the intermediate casing smooth and continuous.

8. The aero-engine intermediate case topology optimization structure design system according to claim 6, characterized in that, It further includes a lattice filling module, which is used to set a mounting seat for fixing the intermediate casing according to the outer wall surface of the outer ring wall plate of the intermediate casing, and fill the lattice in the circumferential area of the mounting seat with a homogeneous cubic lattice with equal rod diameters. The lattice filling area ranges from the outer edge of the mounting seat to the area between the outer edge of the mounting seat and the nearest reinforcing rib, and the filling depth does not exceed 1 / 2 of the casing wall thickness to form a lattice + skeleton structure.

9. The aeroengine intermediate casing topology optimization structure design system according to claim 6, characterized in that, In the topology optimization module, the preset volume fraction ratio of the intermediate casing is: the volume fraction within the lower wall surface of the inner ring wall plate does not exceed the first preset volume fraction ratio, and the volume fraction ratio of the remaining part of the design domain does not exceed the second preset volume fraction ratio.

10. The aero-engine intermediate casing topology optimization structure design system according to claim 6, characterized in that, In the topological optimization module, the weighted compliance of the intermediate casing under all assessment conditions , where , is the total number of assessment conditions, is the compliance weight coefficient of the th assessment condition, ; is the compliance correction value of the th assessment condition, , is the initial compliance of the[[ID=2l]] th assessment condition obtained by simulation, is the structure factor, ranges from 0.8 to 1.5, is the axial force of the intermediate casing under the design point condition, is the axial force of the intermediate casing under the th assessment condition.

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