Topological optimization structure design method and system for intermediate case of aero-engine

Abstract

The invention relates to the technical field of structural design and manufacturing of aero-engines, and discloses a topological optimization structural design method and system for an intermediate case of an aero-engine. Mechanical responses of the intermediate case under different working conditions are accurately captured, mechanical parameters are used as input, finite element analysis is carried out on an initial model of the intermediate case, and a topological optimization structure of the intermediate case is obtained. The initial flexibility and the flexibility weight coefficient of the intermediate case under each examination working condition are obtained; and finally, by taking the artificial pseudo density of the intermediate case analysis model as a design variable and taking the axial force, the torque, the runner cavity pressure and the bearing cavity pressure on the inner side of an inner ring wall plate under each examination working condition as input, realizing the minimization of the weighted flexibility of the intermediate case under the condition of meeting the preset volume fraction constraint of the intermediate case, and finally, realizing the optimal design of the intermediate case. Therefore, the topological optimization configuration of the intermediate case is obtained, and the structural weight of the case is remarkably reduced on the basis of ensuring the strength and rigidity of the intermediate case.

Description

Technical Field

[0001] 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 case. Background Art

[0002] The intermediate case is the main load-bearing framework of the engine. At the same time, it is the overall design and assembly benchmark of the engine, transmitting thrust, torque, etc. to the aircraft, and also undertaking 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, the thrust and torque of the engine, etc., as well as large maneuvering overload, vibration, etc.

[0003] The intermediate case is large in size, thin-walled, and complex in structure. Generally, six to eight hollow webs 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 webs are usually of semi-closed cavity structure. The inner surface of the outer ring wall plate and the outer surface of the splitter ring form the initial section of the engine's outer bypass duct, and the inner surface of the splitter ring and the outer surface of the inner ring wall plate form the inner bypass main flow duct of the engine.

[0004] The intermediate case is a key part in an aero-engine, which has an important impact 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 topology 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, thereby obtaining the topology optimization configuration of the intermediate case, and significantly reducing 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: A topology optimization structure design method for an aero-engine intermediate case, comprising: 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 for dividing 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 the inner ring wall plate is provided with an inner ring bracket for mating connection with the bearing chamber housing. 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 inner ring wall plate inner side bearing cavity pressure of the intermediate casing under multiple assessment conditions. Taking the axial force, torque, flow passage cavity pressure and inner ring wall plate inner side bearing cavity pressure 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. 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. According to the compliance correction values under all assessment conditions, the compliance weight coefficient of each assessment condition is analyzed and obtained. 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 inner ring wall plate inner side bearing cavity pressure under each assessment 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 assessment conditions as the design goal, the analysis model is topologically optimized to obtain the topological optimization configuration of the intermediate casing.

[0008] Furthermore, the surface fitting method is used to reconstruct the topologically optimized model to make the intermediate casing structure smooth and continuous.

[0009] 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 system cubic lattice with equal rod diameters is used to fill the lattice in the circumferential area of the installation seat. The lattice filling area range is the area between the outer edge of the installation seat and the nearest rib 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.

[0010] Furthermore, 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 of the rest of the design domain is not greater than the second preset volume fraction ratio.

[0011] Furthermore, 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, 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 assessment condition.

[0012] To achieve the above technical effects, the present invention also provides an aeroengine intermediate casing topology optimization structure design system, including: A model construction module for obtaining 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 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 chamber housing; A simulation analysis module for simulating and analyzing the initial model by using the finite element analysis method to obtain the axial force, torque, flow channel chamber pressure and inner ring wall plate inner side bearing chamber pressure of the intermediate casing under multiple assessment conditions; A compliance analysis module for taking the axial force, torque, flow channel chamber pressure and inner ring wall plate inner side bearing chamber pressure under each assessment condition as inputs to simulate and analyze the initial model to obtain the initial compliance of the intermediate casing under each assessment condition; A compliance correction module for 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 the compliance correction value corresponding to the assessment condition; A weight coefficient analysis module for analyzing and obtaining the compliance weight coefficient of each assessment condition according to the compliance correction values under all assessment conditions; A topology optimization module, which uses the artificial pseudo-density of the intermediate casing analysis model as the design variable, takes the axial force, torque, flow passage cavity pressure, and inner ring wall plate inner bearing cavity pressure under each assessment condition as inputs, and takes the volume fraction of the intermediate casing not exceeding a preset volume fraction ratio as the constraint condition, and takes the minimum weighted compliance of the intermediate casing under all assessment conditions as the design goal to perform topology optimization on the analysis model, and obtain the topology optimization configuration of the intermediate casing.

[0013] Furthermore, it further includes a model reconstruction module, which is used to reconstruct the topology-optimized model by using the surface fitting method to make the intermediate casing structure smooth and continuous.

[0014] Furthermore, 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 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 does not exceed 1 / 2 of the casing wall thickness, forming a lattice + skeleton structure.

[0015] Furthermore, 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 of the remaining part of the design domain does not exceed the second preset volume fraction ratio.

[0016] Furthermore, in the topology 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 th assessment condition obtained by simulation, is the structure factor, The value range is 0.8 to 1.5, is the axial force of the intermediate casing under the design point condition, is the th assessment condition of the intermediate casing

[0017] 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 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 coefficients of the intermediate casing under each assessment working condition; 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 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 achieved, thereby obtaining the topology optimization configuration of the intermediate casing, significantly reducing the structural weight of the casing while ensuring the strength and stiffness of the intermediate casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a flow chart of the topology optimization structural design method for the intermediate casing of an aero-engine in Embodiment 1; Figure 2 It is a structural schematic diagram of the intermediate casing in Embodiment 1 or 2; Figure 3 It is a structural block diagram of the topology optimization structural design system for the intermediate casing of an aero-engine in Embodiment 1; Figure 4 It is a flow chart of the topology optimization structural design method for the intermediate casing of an aero-engine in Embodiment 2; Figure 5 It is a structural schematic diagram of the stiffening rib and the lattice filling area in Embodiment 1 or 2; Wherein, 1. Outer ring wall plate; 2. Shunt ring; 3. Inner ring wall plate; 4. Load-bearing support plate; 5. Outer flow passage; 6. Inner flow passage; 7. Inner ring support; 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

[0019] The present invention will be further described in detail below in conjunction with the embodiments and the 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.

[0020] Embodiment 1 Referring to Figure 1 、 Figure 2 、 Figure 3 and Figure 5 , a topology optimization structural design method for an intermediate casing of an aero-engine includes: 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 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 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 plate 3 and the outer ring wall plate 1 along the radial direction of the intermediate casing, and an inner ring bracket 7 for mating connection with the bearing chamber housing is arranged on the inner ring wall plate 3; The initial model is simulated and analyzed by using the finite element analysis method to obtain the axial force, torque, flow passage chamber pressure, and bearing chamber pressure on the inner side of the inner ring wall plate 3 of the intermediate casing under multiple assessment conditions; Taking the axial force, torque, flow passage chamber pressure, and bearing chamber pressure on the inner side of the inner ring wall plate 3 under each assessment condition as inputs, the initial compliance of the intermediate casing under each assessment condition is obtained by simulating and analyzing the initial model; 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; According to the compliance correction values under all assessment conditions, the compliance weight coefficient of each assessment condition is analyzed and obtained; Taking the artificial pseudo-density of the intermediate casing analysis model as the design variable, taking the axial force, torque, flow passage chamber pressure, and 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 greater than the 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 topology optimization of the analysis model is carried out to obtain the topology optimization configuration of the intermediate casing.

[0021] In this embodiment, the axial force, torque, flow passage cavity pressure, and the bearing cavity pressure on the inner side of the inner ring wall plate 3 of the intermediate casing are obtained through simulation under multiple assessment conditions, accurately capturing the mechanical responses 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 through normalization of the compliance correction value. Finally, taking the artificial pseudo-density of the intermediate casing analysis model as the design variable and using the axial force, torque, flow passage cavity pressure, and the bearing cavity pressure on the inner side of the inner ring wall plate 3 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 structural weight of the casing while ensuring the strength and stiffness of the intermediate casing.

[0022] Based on the same inventive concept, this embodiment also provides a topology optimization structural design system for an aero-engine intermediate casing, including: A model construction module 10, 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 1, the flow splitting ring 2, the inner ring wall plate 3, and the load-bearing support plate 4 of the intermediate casing; the flow splitting 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. 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 the bearing cavity pressure on the inner side of the inner ring wall plate 3 of the intermediate casing under multiple assessment conditions; 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 the bearing cavity pressure on the inner side of the inner ring wall plate 3 under each assessment condition as inputs to obtain the initial compliance of the intermediate casing under each assessment condition; 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; 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; The topology optimization module 15 is configured to use the artificial pseudo-density of the intermediate casing analysis model as the design variable, take the axial force, torque, flow passage cavity pressure, and the inner ring wall plate 3 inner bearing cavity pressure under each assessment condition as inputs, take the volume fraction of the intermediate casing not being greater than a preset volume fraction ratio as the constraint condition, and take the minimum weighted compliance of the intermediate casing under all assessment conditions as the design objective to perform topology optimization on the analysis model, so as to obtain the topology optimization configuration of the intermediate casing.

[0023] In this embodiment, a model reconstruction module 16 is further included, which is configured to reconstruct the topologically optimized model by using the surface fitting method, so that the intermediate casing structure is smooth and continuous.

[0024] In this embodiment, a lattice filling module 17 is further included, which is configured to set a mounting seat 8 for fixing the intermediate casing according to the outer wall surface of the outer ring wall plate 1 of the intermediate casing, fill the lattice in the circumferential area of the mounting seat 8 with a homogeneous system cubic lattice with equal rod diameters, and the range of the lattice filling area 18 is the area between the outer edge of the mounting seat 8 and the stiffener 9 closest to the outer edge of the mounting seat 8. 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, so as to form a lattice + skeleton structure.

[0025] Embodiment 2 See Figure 2 、 Figure 4 and Figure 5 This embodiment takes the structural design of the intermediate casing of a certain type of aero-engine as an example to elaborate in detail on the method flow of the topology optimization structural design of the aero-engine intermediate casing of the present invention. Among them, the intermediate casing is made of TA15 titanium alloy material, and the specific design steps are as follows: 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 plate 1, the splitter ring 2, the inner ring wall plate 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 plate 3 and the outer ring wall plate 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 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 cooperating and connecting with the bearing cavity housing. In this embodiment, the typical structure of the intermediate casing is as Figure 2 shown. According to the differences in force and function, the outer ring wall plate 1, the splitter ring 2, the inner ring wall plate 3, and the load-bearing support plate 4 of the intermediate casing are split. The tetrahedral elements of the finite element software Hypermesh are used to perform mesh division on the three-dimensional geometric solid models of the split parts; in this embodiment, the tetrahedral unit size is set to 2 mm.

[0026] Then endow the optimized design area with the material properties of TA15 titanium alloy, and the material properties mainly include elastic modulus, density, Poisson's ratio, etc. at different temperatures.

[0027] 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 ring wall plate 3 inner bearing cavity pressure of the intermediate casing under multiple assessment conditions; where: a) Flow passage cavity pressure: Apply it on the surface of the inner flow passage 6 of the outer ring wall plate 1, the inner and outer wall surfaces of the shunt ring 2, and the outer flow passage 5 surface of the inner ring wall plate 3; b) Bearing cavity pressure: Apply it on the inner surface of the inner ring wall plate 3; c) Axial force: The axial force acts on the mounting flange; to ensure the uniformity of loading, couple all the loading nodes together, and use the rbe3 element in Hypermesh to load the cross-section. Select all the nodes on the mounting flange 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; d) Torque: The torque acts on the mounting flange; take the engine axis as the X-axis, the intersection point of the main mounting plane and the axis as the coordinate origin, and the counterclockwise direction as positive.

[0028] Step 3: Take the axial force, torque, flow passage cavity pressure, and inner ring wall plate 3 inner bearing cavity pressure under each assessment condition as inputs, and perform simulation analysis on the initial model to obtain the initial compliance of the intermediate casing under each assessment condition.

[0029] 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; In this embodiment, the compliance correction value of the th assessment condition is , 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 the value range of is 0.8 - 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

[0030] Step 5: According to the compliance correction values under all assessment conditions, analyze and obtain the compliance weight coefficient for each assessment condition; In this embodiment, the Compliance weight coefficient for each assessment condition 。

[0031] Step 6: Using the artificial pseudo-density of the intermediate casing analysis model as the design variable, taking the axial force, torque, flow passage cavity pressure, and inner ring wall plate 3 inner bearing cavity pressure under each assessment condition as inputs, and 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 assessment conditions as the design goal, perform topology optimization on the analysis model to obtain the topology optimization configuration of the intermediate casing; In this embodiment, the artificial pseudo-density of the material in the design unit is used as the design variable, and the goal is to minimize the overall compliance of the intermediate casing. That is, the objective function of the topology optimization is ; where ; Then, apply the constraint conditions for 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 plate 3 not being greater than the first preset volume fraction ratio, and the volume fraction of the remaining part of the design domain not being greater than 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.

[0032] In addition, the constraint conditions in this embodiment also include: Apply the periodic cyclic symmetry constraint, and the number of periods is equal to the number of struts; 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 channel, the struts in the inner channel 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.

[0033] Finally, use the finite element software Hyperworks to complete the topology optimization calculation for the above model.

[0034] Step 7: Use the surface fitting method to reconstruct the model after topology optimization so that the intermediate casing structure is smooth and continuous; In this embodiment, use the UGNX software to reconstruct the model of the intermediate casing after topology optimization, and use the surface fitting method to reconstruct the model after topology optimization so that the stiffening structure is uniform, smooth, and continuous; it is also possible to adjust the fillet at the position where the fillet is too small after local stiffening, and the fillet is set to not be less than R2.0 mm.

[0035] Step 8: An outer wall surface of the outer ring wall plate 1 of the intermediate casing is provided with a mounting seat 8 for fixing the intermediate casing. A homogeneous system cubic lattice with an equal rod diameter is used to fill the lattice in the circumferential area of the mounting seat 8. The range of the lattice filling area 18 is the area between the outer edge of the mounting seat 8 and the stiffener 9 closest to the outer edge of the mounting seat 8. The filling depth is not greater than 1 / 2 of the casing wall thickness, forming a lattice + framework structure; In this embodiment, the topological configuration of the intermediate casing is a periodic cyclic symmetric stiffener 9 structure, and there are obvious stiffener 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 mounting seat 8 area where the stress level is relatively low. In this embodiment, according to the force analysis and process constraints, a lattice filling area 18 can be set in the mounting seat 8 area, and an equal-rod-diameter homogeneous lattice is used for filling. A lattice structure scheme is formed by the shelling method, and no lattice is filled between the mounting seat 8 and the mounting edge of the intermediate casing, so as to obtain an intermediate casing configuration of "lattice + framework", as Figure 5 shown.

[0036] Based on the obtained intermediate casing configuration of "lattice + framework", 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 additive manufacturing process simulation of the intermediate casing model is carried out by using the finite element simulation software. Process supports are set at the positions between the stress-concentrated stiffeners 9 and the stiffeners 9. Process supports are added between the outer ring wall plate 1, the splitter 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 parts.

[0037] In this embodiment, the intermediate casing is further prepared by using the selective laser melting additive manufacturing process scheme. The obtained TA15 titanium alloy intermediate casing with a "lattice + framework" 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.

[0038] The above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A topological optimization structure design method for an aero-engine intermediate case, characterized in that Including: Obtain the initial model of the intermediate casing according to the design structure and aerodynamic shape of the intermediate casing; The initial model includes the outer ring wall plate, the diverter ring, the inner ring wall plate and the 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, 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 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 chamber housing; Use the finite element analysis method to simulate and analyze the initial model, and 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; Taking the axial force, torque, flow channel cavity pressure and inner ring wall plate inner side bearing cavity pressure 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; 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; According to the compliance correction values under all assessment conditions, analyze and obtain the compliance weight coefficient of each assessment condition; Taking the artificial pseudo-density of the intermediate casing analysis model as the design variable, taking the axial force, torque, flow channel cavity pressure and inner ring wall plate inner side bearing cavity pressure under each assessment condition as inputs, taking the volume fraction of the intermediate casing not greater than the 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, 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 aero-engine according to claim 1, wherein, Use the surface fitting method to reconstruct the model after topology optimization 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, characterized in that 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 equal rod diameters is used to fill the lattice in the circumferential area of the installation seat. The lattice filling area range 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 aero-engine according to claim 1, characterized in that, 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 of the rest 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 aero-engine according to claim 1, wherein The weighted compliance of the intermediate casing under all evaluation conditions , where , is the total number of evaluation conditions, is the compliance weight coefficient of the th evaluation condition, ; is the compliance correction value of the th evaluation condition, , is the initial compliance of the intermediate casing obtained by simulation under the th evaluation condition, is the structure factor, whose 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 th evaluation condition.

6. A topological optimization structure design system for an aeroengine intermediate case, characterized in that, Including: A model construction module for obtaining the initial model of the intermediate casing according to the design structure and aerodynamic shape of the intermediate casing; The initial model includes the outer ring wall plate, the diverter ring, the inner ring wall plate and the 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, 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 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 chamber housing; A simulation analysis module, used to simulate and analyze the initial model using a finite element analysis method, to obtain the axial force, torque, flow channel cavity pressure and the bearing cavity pressure on the inner side of the inner ring wall plate of the intermediate casing under multiple assessment conditions; A compliance analysis module is used to perform simulation analysis on the initial model using the axial force, torque, flow channel cavity pressure and the bearing cavity pressure on the inner side of the inner ring wall plate under each test condition as input to obtain the initial compliance of the intermediate casing under each test condition; A 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, so as to obtain a compliance correction value under the corresponding assessment condition; A weight coefficient analysis module, used to analyze and obtain the compliance weight coefficient of each assessment condition according to the compliance correction value under all assessment conditions; A topology optimization module is used to use the artificial pseudo-density of the intermediate casing analysis model as the design variable, the axial force, torque, flow channel cavity pressure and the inner bearing cavity pressure of the inner ring wall plate under each assessment condition as input, the volume ratio of the intermediate casing not being greater than the preset volume ratio as a constraint condition, and the weighted compliance of the intermediate casing under all assessment conditions being minimized as the design goal to perform topological optimization on the analysis model, so as to obtain the topological optimization configuration of the intermediate casing.

7. The topology optimization structural design system of the intermediate casing of an aeroengine according to claim 6, characterized in that, It also includes a model reconstruction module, which is used to reconstruct the topology optimized model using a surface fitting method, so that the intermediate casing structure is smooth and continuous.

8. The aeroengine intermediate casing topology optimization structure design system according to claim 6, characterized in that It also 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 use a homogeneous cubic lattice with equal rod diameter to fill the lattice in the circumferential area of ​​the mounting seat. The lattice filling area ranges from the outer edge of the mounting seat to the area between the reinforcing rib closest to the outer edge of the mounting seat. The filling depth is not more than 1 / 2 of the casing wall thickness, forming a lattice + skeleton structure.

9. The aero-engine intermediate case topology optimization structure design system according to claim 6, characterized in that, In the topology optimization module, the preset volume ratio of the intermediate casing is: the volume ratio within the lower wall surface of the inner ring wall panel is not greater than the first preset volume ratio, and the volume ratio of the remaining design domain is not greater than the second preset volume ratio.

10. The aero-engine intermediate casing topology optimization structure design system according to claim 6, characterized in that, In the topology 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 -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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