Topological Optimization Method, Device, Equipment and Medium for Complex Load Conditions of Aircraft Landing Gear

Abstract

Embodiments of the present application disclose a topology optimization method, device, equipment, and medium for complex load conditions of an aircraft landing gear, belonging to the technical field of structural topology optimization. The method includes: regarding the outer cylinder and the rotating sleeve as a whole, according to different strokes of the piston rod, by the principle of static equilibrium, translating the loads received by the drag strut, piston rod, wheel axle, and torsion arm to the corresponding points on the outer cylinder to obtain the load situation after the force system is simplified; constructing an outer cylinder model, expanding the design domain of the outer cylinder model, dividing the design domain and the non-designable domain, and performing mesh division to obtain multiple mesh regions, adding loads and boundary conditions to the design domain in the mesh regions according to the load situation after the force system is simplified, and performing optimization settings with the minimum compliance as the optimization goal, and then obtaining the topology optimization result based on finite element analysis. The present application can meet the overall performance requirements of complex mechanism systems.

Description

Technical Field

[0001] The present application relates to a topology optimization method, device, equipment and medium for complex load conditions of an aircraft landing gear, and belongs to the technical field of structural topology optimization. Background Art

[0002] The landing gear mechanism bears complex load conditions at the moment of aircraft landing, especially high impact loads at the moment of touchdown. Its main components include an outer cylinder, a piston rod, a rotating sleeve, upper and lower torque arms, a drag strut, a wheel axle and a tire, etc., all of which need to have extremely high strength and durability to ensure structural safety and reliability. Traditional topology optimization methods usually focus on the optimization of individual components, and it is difficult to meet the overall performance requirements of complex mechanism systems. Summary of the Invention

[0003] To solve the above technical problems, the present application provides a topology optimization method, device, equipment and medium for complex load conditions of an aircraft landing gear to meet the overall performance requirements of complex mechanism systems.

[0004] Other features and advantages of the present application will become apparent through the following detailed description, or be learned in part through the practice of the present application.

[0005] According to one aspect of the present application, there is provided a topology optimization method for complex load conditions of an aircraft landing gear. The aircraft landing gear includes an outer cylinder, a rotating sleeve, a drag strut, a torque arm, a piston rod and a tire. The torque arm includes an upper torque arm and a lower torque arm. The rotating sleeve is arranged outside the outer cylinder. The drag strut is arranged outside the outer cylinder. The rotating sleeve connects the piston rod through the upper torque arm and the lower torque arm. The piston rod is movably arranged inside the outer cylinder. One end of the piston rod is arranged on the wheel axle of the tire. The method includes:

[0006] Regarding the outer cylinder and the rotating sleeve as a whole, according to different strokes of the piston rod, by the principle of static equilibrium, translate the loads received by the drag strut, the piston rod, the wheel axle and the torque arm to the corresponding points of the outer cylinder to obtain the load situation after force system simplification;

[0007] Based on the aircraft landing gear, construct an outer cylinder model, and expand the design domain of the outer cylinder model while retaining the necessary structural parameters of the structure;

[0008] According to the outer cylinder model after expanding the design domain, divide the design domain and the non-design domain;

[0009] Mesh the outer cylinder model that divides the design domain and the non-design domain to obtain multiple mesh regions. Add loads and boundary conditions to the design domain in the mesh regions according to the load conditions after the force system is simplified, and perform optimization settings with the minimum compliance as the optimization goal;

[0010] After the optimization settings are completed, perform finite element analysis to obtain the topology optimization result;

[0011] When performing finite element analysis, implement semi-automatic addition of boundary conditions based on the TCL language.

[0012] Furthermore, regard the outer cylinder and the rotating sleeve as a whole. According to different strokes of the piston rod, based on the principle of static equilibrium, translate the loads received by the resistance strut, the piston rod, the wheel axle, and the torsion arm to the corresponding points on the outer cylinder to obtain the load conditions after the force system is simplified, including:

[0013] According to the principle of static equilibrium and the principle of translation of forces, seven equations are obtained by calculating the main vector balance and the main moment balance, namely the first equation, the second equation, the third equation, the fourth equation, the fifth equation, the sixth equation, and the seventh equation; among them:

[0014] Take the piston rod for analysis to obtain the first equation, the second equation, and the third equation, which are respectively expressed as:

[0015] ;

[0016] In the formula, P 1 represents the load at the contact part between the piston rod and the upper part of the outer cylinder, P 2 represents the load at the contact part between the piston rod and the lower part of the outer cylinder, F kx represents the X-direction load at the wheel axle loading point, F 1x represents the X-direction load at the hinge point between the wheel axle and the lower torsion arm, F O represents the load on the top end face of the piston rod, F ky represents the Y-direction load at the wheel axle loading point, F 1y represents the Y-direction load at the hinge point between the wheel axle and the lower torsion arm, Y p1k represents the distance in the Y direction between the contact part between the piston rod and the upper part of the outer cylinder and the wheel axle loading point, Y p2k represents the distance in the Y direction between the contact part between the piston rod and the lower part of the outer cylinder and the wheel axle loading point, X ok represents the distance in the X direction between the top end face of the piston rod and the wheel axle loading point, Y 1kIt represents the distance in the Y direction between the hinge point of the wheel axle and the lower torsion arm and the wheel axle loading point. X 1k It represents the distance in the X direction between the hinge point of the wheel axle and the lower torsion arm and the wheel axle loading point;

[0017] Through overall analysis, the fourth equation, the fifth equation, and the sixth equation are obtained, which are respectively expressed as:

[0018] ;

[0019] In the formula, F 3x It represents the X-direction load at the hinge point of the upper torsion arm and the rotating sleeve, F 3y It represents the Y-direction load at the hinge point of the upper torsion arm and the rotating sleeve, Y 3k It represents the distance in the Y direction between the hinge point of the upper torsion arm and the rotating sleeve and the wheel axle loading point, X 3k It represents the distance in the X direction between the hinge point of the upper torsion arm and the rotating sleeve and the wheel axle loading point;

[0020] The seventh equation is expressed as:

[0021] ;

[0022] In the formula, Y 23 It represents the distance in the Y direction between the hinge point of the upper torsion arm and the lower torsion arm and the hinge point of the upper torsion arm and the rotating sleeve, X 23 It represents the distance in the X direction between the hinge point of the upper torsion arm and the lower torsion arm and the hinge point of the upper torsion arm and the rotating sleeve;

[0023] Based on the above seven equations, the load condition after the force system is simplified is solved.

[0024] Furthermore, with the minimum flexibility as the optimization objective, the optimization settings are as follows:

[0025] Set the element density of the elements within the design domain as a variable;

[0026] Set constraints, with the upper limit of the volume fraction being 0.3;

[0027] With the minimum flexibility as the optimization objective, construct an optimization formulation;

[0028] Based on the optimization formulation and the set constraints, set optimization parameters to perform optimization to obtain the optimal element density of the elements within the design domain; among them, the optimization parameters include the minimum size of the optimization and the penalty factor.

[0029] Furthermore, the optimization formulation is expressed as:

[0030] ;

[0031] wherein, min represents minimization, represents flexibility, U T represents the transpose matrix of the global displacement matrix, U represents the global displacement matrix, K represents the stiffness matrix, represents the element number, N represents the number of elements, represents the design variable, P represents the penalty factor, represents the transpose matrix of the element displacement matrix, represents the element displacement matrix, represents the element stiffness matrix, represents the optimized volume, represents the volume of the design domain, f represents the volume fraction, F represents the load vector, x min represents the minimum relative density of the element.

[0032] Further, the optimized minimum size is 6 times the element size.

[0033] Further, after the optimization settings are completed, finite element analysis is performed to obtain the topology optimization result, including:

[0034] Based on the finite element model, the loads and analysis steps of multiple working conditions are set, and the finite element solver is used to perform topology optimization on the model to obtain the topology optimization result.

[0035] Further, when performing finite element analysis, semi-automatic addition of boundary conditions is realized based on the TCL language, including:

[0036] Performing tetrahedral mesh division on the imported outer cylinder model;

[0037] Creating different materials and properties and assigning the properties to the corresponding tetrahedral meshes;

[0038] Creating different composites, load collectors and load steps;

[0039] Creating rigid connection elements corresponding to the buffer stroke in the corresponding composite;

[0040] Creating loads corresponding to the corresponding working conditions on the corresponding rigid connection elements.

[0041] According to an aspect of the present application, there is also provided a topology optimization device for complex load conditions of an aircraft landing gear. The aircraft landing gear includes an outer cylinder, a rotating sleeve, a drag strut, a torque arm, a piston rod, and a tire. The torque arm includes an upper torque arm and a lower torque arm. The rotating sleeve is disposed outside the outer cylinder. The drag strut is disposed outside the outer cylinder. The rotating sleeve connects the piston rod through the upper torque arm and the lower torque arm. The piston rod is movably disposed within the outer cylinder. One end of the piston rod is disposed on the axle of the tire. The device includes:

[0042] A force system simplification module configured to regard the outer cylinder and the rotating sleeve as an integral body, and according to different strokes of the piston rod, by the principle of static equilibrium, translate the loads received by the drag strut, the piston rod, the axle, and the torque arm to the corresponding points of the outer cylinder to obtain the load situation after the force system is simplified;

[0043] A topology optimization module configured to construct an outer cylinder model based on the aircraft landing gear, expand the design domain of the outer cylinder model while retaining the necessary structural parameters of the structure; divide the design domain and the non-designable domain according to the outer cylinder model after expanding the design domain; perform mesh division on the outer cylinder model divided into the design domain and the non-designable domain to obtain a plurality of mesh regions, add loads and boundary conditions to the design domain in the mesh regions according to the load situation after the force system is simplified, and perform optimization settings with the minimum compliance as the optimization goal; after the optimization settings are completed, perform finite element analysis to obtain the topology optimization result;

[0044] A boundary addition module configured to semi-automatically add boundary conditions based on the TCL language when performing finite element analysis.

[0045] According to an aspect of the present application, there is also provided an electronic device, including: a controller; a memory for storing one or more programs, and when the one or more programs are executed by the controller, the controller implements the topology optimization method for complex load conditions of the aircraft landing gear described above.

[0046] According to an aspect of the present application, there is also provided a computer-readable storage medium, on which computer-readable instructions are stored, and when the computer-readable instructions are executed by a processor of a computer, the computer executes the topology optimization method for complex load conditions of the aircraft landing gear described above.

[0047] In the technical solution provided by the present application, there are at least the following advantages:

[0048] This application aims at complex landing gear mechanisms, derives the load transfer path through theoretical mechanics methods, and applies it to the outer cylinder of key components, thereby achieving a more reasonable load distribution and topology optimization in the overall system. Additionally, during the optimization process, a self-written TCL language script is introduced to apply boundary conditions more efficiently and quickly, effectively improving the calculation efficiency and simplifying the operation process. This optimization method not only enhances the accuracy of the overall design but also significantly improves the load-bearing performance and structural lightweight level of the landing gear.

[0049] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit this application. Brief Description of the Drawings

[0050] The drawings herein are incorporated into the specification and form a part of this specification, showing embodiments consistent with this application, and are used together with the specification to explain the principles of this application. Obviously, the drawings in the following description are only some embodiments of this application, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts. In the drawings:

[0051] Figure 1 is a three-dimensional structural diagram of an aircraft landing gear according to the prior art; wherein, 101 is the outer cylinder, 102 is the rotating sleeve, 103 is the drag strut, 104 is the piston rod, 105 is the tire, 106 is the upper torque arm, and 107 is the lower torque arm.

[0052] Figure 2 is the overall flowchart of the topology optimization method for complex load conditions of an aircraft landing gear shown in an exemplary embodiment of this application.

[0053] Figure 3 is a schematic diagram of the system load and boundary conditions of an aircraft landing gear shown in an exemplary embodiment of this application.

[0054] Figure 4 is a mechanical schematic diagram of the piston rod, torque arm, and wheel axle shown in an exemplary embodiment of this application; wherein, X 、 Y 、 Z are respectively the three coordinate axes of the space coordinate system, O is the top end face of the piston rod, P 1z is the Z-direction load at the contact part of the piston rod and the upper part of the outer cylinder, P 1x is the X-direction load at the contact part of the piston rod and the upper part of the outer cylinder, P 2x is the X-direction load at the contact part of the piston rod and the lower part of the outer cylinder, P 2zis the Z - direction load at the contact part between the piston rod and the lower part of the outer cylinder. a , b , c All represent rods, corresponding to the piston rod, the upper torsion arm, and the lower torsion arm respectively; O 1 is the lower end face of the piston rod, 1 is the hinge point between the axle and the lower torsion arm, 2 is the hinge point between the upper torsion arm and the lower torsion arm, 3 is the hinge point between the upper torsion arm and the rotating sleeve, k is the axle loading point.

[0055] Figure 5 is a schematic structural diagram of the outer cylinder model after expanding the design domain shown in an exemplary embodiment of the present application.

[0056] Figure 6 is the model structure diagram after dividing the design domain and non - design domain shown in an exemplary embodiment of the present application; among them, (a) is the overall drawing of the design area division, and (b) is the sectional view of the design area division.

[0057] Figure 7 is the topology optimization result diagram shown in an exemplary embodiment of the present application; among them, (a) represents the overall result, (b) represents the upper - half result, and (c) represents the lower - half result.

[0058] Figure 8 is the optimized unit density cloud diagram shown in an exemplary embodiment of the present application; among them, (a) and (b) respectively represent the unit density cloud diagrams with different unit density sizes.

[0059] Figure 9 is the structural diagram of a topology optimization device for complex load conditions of an aircraft landing gear shown in an exemplary embodiment of the present application; among them, 91 is the force system simplification module, 92 is the topology optimization module, and 93 is the boundary addition module. Detailed implementation manners

[0060] Here, the exemplary embodiments will be described in detail, and the examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the present application. On the contrary, they are merely examples of the devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0061] The block diagrams shown in the drawings are only functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0062] The flowcharts shown in the accompanying drawings are merely illustrative and not necessarily include all content and operations / steps, nor are they necessarily executed in the described order. For example, some operations / steps can be decomposed, while some operations / steps can be combined or partially combined. Therefore, the actual execution order may change according to the actual situation.

[0063] As used in this application, "a plurality of" means two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0064] Please refer to Figure 1 , Figure 1 is a three-dimensional structure diagram of an aircraft landing gear according to the prior art. As Figure 1 shown, this aircraft landing gear is the front landing gear of the aircraft, including an outer cylinder 101, a rotating sleeve 102, a drag strut 103, a piston rod 104, a torsion arm, and a tire 105. The torsion arm includes an upper torsion arm 106 and a lower torsion arm 107. One end of the piston rod 104 is connected to the axle of the tire 105. The piston rod 104 is movable only within the outer cylinder 101. The drag strut 103 is hinged to the outside of the outer cylinder 101 to play a supporting role. The rotating sleeve 102 is sleeved on the outside of the outer cylinder 101. The rotating sleeve 102 is connected to the piston rod 104 through the upper torsion arm 106 and the lower torsion arm 107. By rotating the rotating sleeve 102, force is transmitted through the upper torsion arm 106 and the lower torsion arm 107, causing the piston rod 104 to move up and down inside the outer cylinder 101, thereby realizing the lifting of the tire 105.

[0065] It should be noted that although the piston rod 104 extends and retracts in the outer cylinder 101, in fact, there are only two places, the upper and lower, where the piston rod 104 contacts the outer cylinder 101, and there is no interaction between the entire outer surface of the piston rod 104 and the entire inner surface of the outer cylinder 101.

[0066] The embodiment of the present application provides a topology optimization method for complex load conditions of an aircraft landing gear. This topology optimization method can be applied to the aircraft landing gear as Figure 1 shown. It can be understood that the method proposed in the present application is not limited to the application of the aircraft landing gear as Figure 1 shown. It can also be extended to aircraft landing gears with other structural forms. This is only an example here and not a limitation to the present application. Please refer to Figure 2 , which is the overall flowchart of the topology optimization method for complex load conditions of an aircraft landing gear shown in an exemplary embodiment of the present application. This method includes steps S10 to step S30, which are introduced in detail as follows.

[0067] S10: Simplification of spatial force system.

[0068] In this embodiment, the specific way to realize the simplification of the spatial force system in step S10 is as follows: Regarding the outer cylinder and the rotating sleeve as a whole, according to different strokes of the piston rod, by the principle of static equilibrium, the loads received by the resistance strut, the piston rod, the wheel axle, and the torsion arm are translated to the corresponding points on the outer cylinder, and the load condition after the force system is simplified is obtained.

[0069] Exemplarily, based on Figure 1 the shown aircraft landing gear, the system loads and boundary conditions of the aircraft landing gear are as Figure 3 shown. In order to simplify the simulation of the force condition of the outer cylinder, when performing finite element analysis on the outer cylinder 101, the outer cylinder 101 and the rotating sleeve 102 are regarded as a whole, and based on the outer cylinder 101 and the support model, according to different strokes of the piston rod 104, by the principle of static equilibrium, the loads received by components such as the resistance strut 103, the piston rod 104, the wheel axle, and the torsion arm are translated to the corresponding points on the outer cylinder 101, and the mechanical schematic diagrams of the piston rod, the torsion arm, and the wheel axle as shown in Figure 4 are obtained, so as to more quickly and simply simulate the actual loaded condition.

[0070] It can be known from Figure 3 that when the load direction only exists in the xOy plane, according to the principle of static equilibrium and the principle of force translation, seven equations are obtained by calculating the main vector equilibrium and the main moment equilibrium, which are the first equation, the second equation, the third equation, the fourth equation, the fifth equation, the sixth equation, and the seventh equation respectively.

[0071] Among them:

[0072] Taking the piston rod for analysis, the first equation, the second equation, and the third equation are obtained, which are respectively expressed as:

[0073] ;

[0074] In the formula, P 1 represents the load at the contact part between the piston rod and the upper part of the outer cylinder, P 2 represents the load at the contact part between the piston rod and the lower part of the outer cylinder, F kx represents the X-direction load at the wheel axle loading point, F 1x represents the X-direction load at the hinge point between the wheel axle and the lower torsion arm, F O represents the load on the top end face of the piston rod, F ky represents the Y-direction load at the wheel axle loading point, F 1y represents the Y-direction load at the hinge point between the wheel axle and the lower torsion arm, Y p1kIt represents the distance in the Y direction between the contact part of the piston rod and the upper part of the outer cylinder and the wheel axle loading point. Y p2k It represents the distance in the Y direction between the contact part of the piston rod and the lower part of the outer cylinder and the wheel axle loading point. X ok It represents the distance in the X direction between the top end face of the piston rod and the wheel axle loading point. Y 1k It represents the distance in the Y direction between the hinge point of the wheel axle and the lower torsion arm and the wheel axle loading point. X 1k It represents the distance in the X direction between the hinge point of the wheel axle and the lower torsion arm and the wheel axle loading point.

[0075] It should be noted that, please combine Figure 3 and Figure 4 As shown, the load of the contact part of the piston rod and the upper part of the outer cylinder P 1 is composed of the Z-direction load P 1z of the contact part of the piston rod and the upper part of the outer cylinder and the X-direction load P 1x of the contact part of the piston rod and the upper part of the outer cylinder; the load P 2 of the contact part of the piston rod and the lower part of the outer cylinder is composed of the X-direction load P 2x of the contact part of the piston rod and the lower part of the outer cylinder and the Z-direction load P 2z of the contact part of the piston rod and the lower part of the outer cylinder.

[0076] Through overall analysis, the fourth equation, the fifth equation and the sixth equation are obtained, which are respectively expressed as:

[0077] ;

[0078] In the formula, F 3x represents the X-direction load of the hinge point of the upper torsion arm and the rotating sleeve, F 3y represents the Y-direction load of the hinge point of the upper torsion arm and the rotating sleeve, Y 3k represents the distance in the Y direction between the hinge point of the upper torsion arm and the rotating sleeve and the wheel axle loading point, X 3k represents the distance in the X direction between the hinge point of the upper torsion arm and the rotating sleeve and the wheel axle loading point.

[0079] At this time, through mechanical analysis, it is known that rod c is a two-force member, so the seventh equation can be obtained and expressed as:

[0080] ;

[0081] In the formula,Y 23 It represents the distance in the Y direction between the hinge point of the upper torsion arm and the lower torsion arm and the hinge point of the upper torsion arm and the rotating sleeve. X 23 It represents the distance in the X direction between the hinge point of the upper torsion arm and the lower torsion arm and the hinge point of the upper torsion arm and the rotating sleeve.

[0082] Solve the above seven equations to obtain the load condition after the force system is simplified.

[0083] Meanwhile, according to Figure 3 , when there is a Z-direction load, for the Z-direction load at the wheel axle loading point k , first, by the principle of translation of forces, translate the Z-direction load at the wheel axle loading point k along the xOz plane to the yOz plane, and a P 1z , P 2z in the same plane can be obtained. Meanwhile, a moment on the rod is obtained. Apply a Z-direction load F a at the hinge point 3 of the upper torsion arm and the rotating sleeve. This 3z , this F 3z the moment on the rod a is equivalent to the F kz translated moment . Calculate the Z-direction loads P 1z , P 2z at the contact part P1 between the piston rod and the upper part of the outer cylinder and the contact part P2 between the piston rod and the lower part of the outer cylinder according to the principle of static equilibrium and the principle of translation of forces. Thus, the processing of the Z-direction load at the wheel axle loading point k is completed.

[0084] When there is a Z-direction load at the hinge point 2 of the upper torsion arm and the lower torsion arm, the Z-direction load at the hinge point 2 of the upper torsion arm and the lower torsion arm can be transferred to the hinge point 3 of the upper torsion arm and the rotating sleeve by the moment equivalence of the rod a .

[0085] Based on the solutions obtained above and according to the actual situation, convert the loads on the contact part P1 between the piston rod and the upper part of the outer cylinder, the contact part P2 between the piston rod and the lower part of the outer cylinder, the top end face O of the piston rod, and the hinge point 3 of the upper torsion arm and the rotating sleeve into pressure or reaction force acting on the outer cylinder and the support.

[0086] S20: Topological optimization of the outer cylinder of the aircraft landing gear.

[0087] In this embodiment, the specific process of the topology optimization of the outer cylinder of the aircraft landing gear is as follows: Based on the aircraft landing gear, an outer cylinder model is constructed. While retaining the necessary structural parameters of the structure, the design domain of the outer cylinder model is expanded; according to the outer cylinder model after expanding the design domain, the design domain and the non-design domain are divided; the outer cylinder model with the design domain and the non-design domain divided is meshed to obtain a plurality of mesh regions. Loads and boundary conditions are added to the design domain in the mesh regions according to the load conditions after the force system is simplified, and optimization settings are carried out with the minimum compliance as the optimization goal; after the optimization settings are completed, finite element analysis is performed to obtain the topology optimization result.

[0088] In an exemplary embodiment, while retaining the necessary structural parameters of the structure, the design domain of the model is expanded, and the structure of the expanded model is as Figure 5 shown.

[0089] While retaining the necessary structural parameters of the structure (such as the size and position of the holes on the large lugs of the outer cylinder, etc.), the design domain and the non-design domain are divided according to the model of the expanded design domain, and the structure of the divided model is as Figure 6 shown.

[0090] Subsequently, the following steps S21 to S25 are used to perform optimization settings on the divided model structure as Figure 6 shown:

[0091] S21: Define design variables: In this optimization, the design variables are defined as the element densities of the elements within the design domain of the outer cylinder.

[0092] S22: Constraint setting: The upper limit of the constrained volume fraction is set to 0.3.

[0093] S23: Define the optimization goal: The minimum compliance is the optimization goal.

[0094] S24: Determine the optimization formulation:

[0095] ;

[0096] In the formula, min represents minimization, represents compliance, U T represents the transpose matrix of the global displacement matrix, U represents the global displacement matrix, K represents the stiffness matrix, represents the element number, N represents the number of elements, represents the design variable, P represents the penalty factor, represents the transpose matrix of the element displacement matrix, represents the element displacement matrix, represents the element stiffness matrix, Denotes the optimized volume, Denotes the design domain volume, f Denotes the volume fraction, F Denotes the load vector, x min Denotes the minimum relative density of the element.

[0097] Among the above optimization formulations, Denotes the volume constraint, which is used to ensure that the optimized volume is not greater than a set percentage of the volume before optimization.

[0098] Is an optimized control equation, which gives a range of element densities between 0 and 1. If the design variable is 0, the elements in this part do not exist; if the design variable is 1, all these elements exist.

[0099] S25: Optimization parameter settings: The minimum size for this optimization is set to 18 mm (6 times the element size); the penalty factor is 3.

[0100] After completing the above steps S21 to S25, based on the finite element model, set the corresponding analysis steps to complete the load and analysis step settings for 31 working conditions. Using the OptiStruct solver, perform topology optimization on the model, and the optimization results are as Figure 7 shown, and the element density of the optimized outer cylinder is as Figure 8 shown. From Figure 7 and Figure 8 it can be seen that the material is concentrated in the middle and lower sections of the outer cylinder because the outer cylinder mainly bears bending loads under these working conditions. And the connection between the upper end of the outer cylinder and the body is connected by a straight rib plate structure at a certain angle. This material distribution can minimize the use of materials to the greatest extent while meeting the usage conditions.

[0101] S30: Realize semi-automatic addition of boundary conditions based on TCL language.

[0102] The landing gear will experience various load conditions during the landing process, and the stroke of the piston rod varies under different load conditions. Therefore, multiple modelings are required in finite element analysis, and this repeated modeling is prone to errors and time-consuming. To address this issue, in this embodiment, TCL language is used to perform secondary development on HyperMesh, and a semi-automatic load and stroke addition function is designed, which can quickly adapt to the topology optimization requirements under different strokes and load conditions. This tool significantly reduces the modeling workload and the incidence of human errors, and improves the analysis efficiency and design accuracy.

[0103] Specifically, step S30 can be implemented by the following steps S31 to S35.

[0104] S31: Perform tetrahedral mesh generation on the imported outer cylinder model;

[0105] S32: Create different materials and properties, and assign the properties to the corresponding meshes;

[0106] S33: Create different composites, load collectors, and load steps;

[0107] S34: Create rigid connection units corresponding to the buffer stroke in the corresponding composite;

[0108] S35: Create loads corresponding to the working conditions on the corresponding rigid connection units.

[0109] It should be noted that the rigid connection unit (or RBE3 unit) is a special type of connection unit used in finite element analysis. It is used to describe the relationship between multiple nodes and constrain the displacements and rotations of multiple nodes together.

[0110] Please refer to Figure 9 , Figure 9 which is the structural diagram of a topology optimization device for complex load conditions of an aircraft landing gear shown in an exemplary embodiment of the present application. On the other hand, an embodiment of the present invention also provides a topology optimization device for complex load conditions of an aircraft landing gear. The aircraft landing gear includes an outer cylinder, a rotating sleeve, a drag strut, a torque arm, a piston rod, and a tire. The torque arm includes an upper torque arm and a lower torque arm. The rotating sleeve is disposed outside the outer cylinder. The drag strut is disposed outside the outer cylinder. The rotating sleeve connects the piston rod through the upper torque arm and the lower torque arm. The piston rod is movably disposed within the sleeve. One end of the piston rod is disposed on the axle of the tire. The device includes:

[0111] A force system simplification module 91, configured to regard the outer cylinder and the rotating sleeve as a whole, and according to different strokes of the piston rod, translate the loads received by the drag strut, the piston rod, the axle, and the torque arm to the corresponding points on the outer cylinder through the principle of static equilibrium to obtain the load situation after force system simplification;

[0112] A topology optimization module 92, configured to construct an outer cylinder model based on the aircraft landing gear, expand the design domain of the outer cylinder model while retaining the necessary structural parameters of the structure; divide the design domain and the non-design domain according to the expanded outer cylinder model; perform mesh division on the outer cylinder model divided into the design domain and the non-design domain to obtain multiple mesh regions, add loads and boundary conditions on the design domain in the mesh regions according to the load situation after force system simplification, and perform optimization settings with the minimum compliance as the optimization goal; after the optimization settings are completed, perform finite element analysis to obtain the topology optimization result;

[0113] A boundary addition module 93, configured to semi-automatically add boundary conditions based on the TCL language when performing finite element analysis.

[0114] It should be noted that the topology optimization device for complex load conditions of an aircraft landing gear provided in the above embodiments and the topology optimization method for complex load conditions of an aircraft landing gear provided in the foregoing embodiments belong to the same concept. The specific manners of performing the steps have been described in detail in the method embodiments and will not be elaborated here.

[0115] On the other hand, the present application also provides an electronic device, including: a controller; a memory for storing one or more programs, which, when executed by the controller, are configured to execute the topology optimization method for complex load conditions of an aircraft landing gear in the above various embodiments.

[0116] Specifically, according to the embodiments of the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments of the present application include a computer program product, which includes a computer program carried on a computer-readable medium. The computer program includes a computer program for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through the communication part and / or installed from a removable medium. When the computer program is executed by a central processing unit (CPU), various functions defined in the system of the present application are executed.

[0117] It should be noted that the computer-readable medium shown in the embodiments of the present application may be a computer-readable signal medium, a computer-readable storage medium, or any combination of the two. A computer-readable storage medium may be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples of the computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, the computer-readable storage medium may be any tangible medium that contains or stores a program, and the program may be used by or in conjunction with an instruction execution system, apparatus, or device. In the present application, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, which carries a computer-readable computer program. Such a propagated data signal may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device. The computer program contained on the computer-readable medium may be transmitted by any appropriate medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0118] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments of the present application. Among them, each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and the above module, program segment, or part of code contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in an order different from that marked in the accompanying drawings. For example, two consecutive blocks shown may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram or flowchart, as well as the combination of blocks in the block diagram or flowchart, may be implemented by a dedicated hardware-based system for performing the specified functions or operations, or may be implemented by a combination of dedicated hardware and computer instructions.

[0119] The modules / units involved in the embodiments of the present application can be implemented in software or in hardware, and the described units can also be provided in a processor. Among them, the names of these modules / units do not, in some cases, constitute a limitation on the modules / units themselves.

[0120] Another aspect of the present application also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the topological optimization method for complex load conditions of an aircraft landing gear as described above. The computer-readable storage medium may be included in the electronic device described in the above embodiments, or may exist independently and not be assembled into the electronic device.

[0121] Another aspect of the present application also provides a computer program product or a computer program. The computer program product or the computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. The processor of the computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the topological optimization method for complex load conditions of an aircraft landing gear provided in the above various embodiments.

[0122] According to one aspect of the embodiments of the present application, a computer system is also provided, including a central processing unit (CPU). The CPU can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) or a program loaded from a storage section into a random access memory (RAM), such as executing the method in the above embodiments. In the RAM, various programs and data required for system operation are also stored. The CPU, ROM, and RAM are connected to each other through a bus. An input / output (I / O) interface is also connected to the bus.

[0123] The following components are connected to the I / O interface: an input section including a keyboard, a mouse, etc.; an output section including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage section including a hard disk, etc.; and a communication section including a network interface card such as a LAN (Local Area Network) card, a modem, etc. The communication section performs communication processing via a network such as the Internet. A drive is also connected to the I / O interface as needed. A removable medium such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc. is installed on the drive as needed so that a computer program read therefrom is installed in the storage section as needed.

[0124] The above content is only a preferred exemplary embodiment of the present application and is not used to limit the implementation of the present application. Those of ordinary skill in the art can easily make corresponding adaptations or modifications according to the main concept and spirit of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope required by the claims.

Claims

1. A topological optimization method for complex load conditions of an aircraft landing gear, the aircraft landing gear comprising an outer tube, a rotating sleeve, a resistance strut, a torque arm, a piston rod and a tire, the torque arm comprising an upper torque arm and a lower torque arm, the rotating sleeve is arranged on the outside of the outer tube, the resistance strut is arranged on the outside of the outer tube, the rotating sleeve is connected to the piston rod through the upper torque arm and the lower torque arm, the piston rod is movably arranged in the outer tube, one end of the piston rod is arranged on the wheel axle of the tire, characterized in that, The method comprises: The outer cylinder and the rotating sleeve are regarded as one body. According to the different strokes of the piston rod, the loads on the resistance support rod, the piston rod, the axle and the torque arm are translated to the corresponding points of the outer cylinder through the principle of static balance to obtain the load situation after the force system is simplified. An outer cylinder model is constructed based on the aircraft landing gear, and a design domain of the outer cylinder model is expanded while retaining necessary structural parameters of the structure; According to the outer cylinder model after the design domain is expanded, the design domain and the non-designable domain are divided; Meshing the outer cylinder model that divides the design domain and the non-designable domain to obtain a plurality of mesh regions, adding loads and boundary conditions to the design domain in the mesh regions according to the load conditions after the force system is simplified, and performing optimization settings with minimum flexibility as the optimization goal; After the optimization settings are completed, finite element analysis is performed to obtain topology optimization results; When performing finite element analysis, boundary conditions are semi-automatically added based on TCL language; The outer cylinder and the rotating sleeve are considered as one body. According to the different strokes of the piston rod, the loads on the resistance support rod, piston rod, axle and torque arm are translated to the corresponding points of the outer cylinder through the principle of static balance, and the load situation after the force system is simplified is obtained, including: According to the principle of static balance and the principle of force translation, seven equations are obtained by calculating the principal vector balance and the principal moment balance, namely the first equation, the second equation, the third equation, the fourth equation, the fifth equation, the sixth equation and the seventh equation; among them: Taking the piston rod analysis, we get the first equation, the second equation and the third equation, which are expressed as: ； In the formula, P 1 represents the load at the contact point between the piston rod and the upper part of the outer tube. P 2 represents the load at the contact point between the piston rod and the lower part of the outer tube. F kx represents the X-direction load at the axle loading point, F 1x Indicates the X-direction load at the hinge point between the wheel axle and the lower torque arm, F O Indicates the end load on the piston rod top. F ky represents the Y-axis load at the axle loading point, F 1y Indicates the Y-axis load at the hinge point between the wheel axle and the lower torque arm, Y p1k Indicates the distance between the contact point between the piston rod and the upper part of the outer cylinder and the axle loading point in the Y direction. Y p2k Indicates the distance between the contact point between the piston rod and the lower part of the outer cylinder and the axle loading point in the Y direction. X ok Indicates the distance between the top end of the piston rod and the axle loading point in the X direction, Y 1k Indicates the distance between the hinge point between the wheel axle and the lower torque arm and the wheel axle loading point in the Y direction, X 1k Indicates the distance between the hinge point between the wheel axle and the lower torque arm and the wheel axle loading point in the X direction; Overall analysis yields the fourth, fifth, and sixth equations, which are expressed as: ； In the formula, F 3x Indicates the X-axis load at the hinge point between the upper torque arm and the rotating sleeve, F 3y Indicates the Y-axis load at the hinge point between the upper torque arm and the rotating sleeve, Y 3k Indicates the distance between the upper torque arm and the rotating sleeve hinge point and the axle loading point in the Y direction, X 3k Indicates the distance between the hinge point of the upper torque arm and the rotating sleeve and the axle loading point in the X direction; The seventh equation is expressed as: ； In the formula, Y 23 Indicates the distance between the hinge point of the upper torque arm and the lower torque arm and the hinge point of the upper torque arm and the rotating sleeve in the Y direction, X 23 Indicates the distance between the hinge point of the upper torque arm and the lower torque arm and the hinge point of the upper torque arm and the rotating sleeve in the X direction; Based on the seven equations, the load condition of the simplified force system is obtained.

2. The topology optimization method for complex load conditions of aircraft landing gear according to claim 1, characterized in that: The optimization setting is carried out with the minimum flexibility as the optimization goal, including: Set the cell density of the cells in the design domain as a variable; Set constraints, and the upper limit of the constraint volume fraction is 0.3; Taking the minimum flexibility as the optimization goal, the optimization formula is constructed; Based on the optimization formula and the set constraints, the optimization parameters are set for optimization to obtain the optimal cell density of the cells in the design domain; wherein the optimization parameters include the minimum size of the optimization and the penalty factor.

3. The topology optimization method for complex load conditions of aircraft landing gear according to claim 2, characterized in that: The optimization column is expressed as: ； In the formula, min means minimization, Indicates softness, U T represents the transposed matrix of the overall displacement matrix, U represents the overall displacement matrix, K represents the stiffness matrix, Indicates the unit number, N Indicates the number of units, represents the design variable, P represents the penalty factor, represents the transposed matrix of the unit displacement matrix, represents the unit displacement matrix, represents the element stiffness matrix, Represents the optimized volume, represents the design domain volume, f represents the volume fraction, F represents the load vector, x min Indicates the minimum relative density of the unit.

4. The topology optimization method for complex load conditions of aircraft landing gear according to claim 2, characterized in that: The optimized minimum size is 6 times the cell size.

5. The topology optimization method for complex load conditions of aircraft landing gear according to claim 1, characterized in that: After the optimization settings are completed, finite element analysis is performed to obtain topology optimization results, including: On the basis of the finite element model, the loads and analysis steps of various working conditions are set, and the model is topologically optimized using the finite element solver to obtain the topological optimization results.

6. The topology optimization method for complex load conditions of aircraft landing gear according to claim 5, characterized in that: When performing finite element analysis, boundary conditions are semi-automatically added based on TCL language, including: Perform tetrahedral meshing on the imported outer cylinder model; Create different materials, properties, and assign the properties to the corresponding tetrahedral meshes; Create different complexes, load collectors, and load steps; Creating a rigid connection unit corresponding to the buffer stroke in the corresponding complex; Create loads for the corresponding load cases on the corresponding rigid connection elements.

7. A topological optimization device for complex load conditions of an aircraft landing gear, the aircraft landing gear comprising an outer tube, a rotating sleeve, a resistance strut, a torque arm, a piston rod and a tire, the torque arm comprising an upper torque arm and a lower torque arm, the rotating sleeve is arranged on the outside of the outer tube, the resistance strut is arranged on the outside of the outer tube, the rotating sleeve is connected to the piston rod through the upper torque arm and the lower torque arm, the piston rod is movably arranged in the outer tube, one end of the piston rod is arranged on the wheel axle of the tire, characterized in that, The device comprises: The force system simplification module is configured to regard the outer cylinder and the rotating sleeve as one body. According to the different strokes of the piston rod, the loads on the resistance support rod, the piston rod, the wheel axle and the torque arm are translated to the corresponding points of the outer cylinder through the principle of static balance to obtain the load situation after the force system is simplified. A topology optimization module is configured to construct an outer cylinder model based on the aircraft landing gear, expand the design domain of the outer cylinder model while retaining the necessary structural parameters of the structure; divide the design domain and the non-design domain according to the outer cylinder model after the design domain is expanded; mesh the outer cylinder model divided into the design domain and the non-design domain to obtain multiple mesh areas, add loads and boundary conditions to the design domain in the mesh area according to the load conditions after the force system is simplified, and perform optimization settings with minimum flexibility as the optimization goal; after the optimization settings are completed, perform finite element analysis to obtain topology optimization results; A boundary adding module is configured to implement semi-automatic addition of boundary conditions based on TCL language when performing finite element analysis; The force system simplification module is further configured to obtain seven equations by calculating the principal vector balance and the principal moment balance according to the principle of static force balance and the principle of force translation, namely, the first equation, the second equation, the third equation, the fourth equation, the fifth equation, the sixth equation and the seventh equation; wherein: Taking the piston rod analysis, we get the first equation, the second equation and the third equation, which are expressed as: ； In the formula, P 1 represents the load at the contact point between the piston rod and the upper part of the outer tube. P 2 represents the load at the contact point between the piston rod and the lower part of the outer tube. F kx represents the X-direction load at the axle loading point, F 1x Indicates the X-direction load at the hinge point between the wheel axle and the lower torque arm, F O Indicates the end load on the piston rod top. F ky represents the Y-axis load at the axle loading point, F 1y Indicates the Y-axis load at the hinge point between the wheel axle and the lower torque arm, Y p1k Indicates the distance between the contact point between the piston rod and the upper part of the outer cylinder and the axle loading point in the Y direction. Y p2k Indicates the distance between the contact point between the piston rod and the lower part of the outer cylinder and the axle loading point in the Y direction. X ok Indicates the distance between the top end of the piston rod and the axle loading point in the X direction, Y 1k Indicates the distance between the hinge point between the wheel axle and the lower torque arm and the wheel axle loading point in the Y direction, X 1k Indicates the distance between the hinge point between the wheel axle and the lower torque arm and the wheel axle loading point in the X direction; Overall analysis yields the fourth, fifth, and sixth equations, which are expressed as: ； In the formula, F 3x Indicates the X-axis load at the hinge point between the upper torque arm and the rotating sleeve, F 3y Indicates the Y-axis load at the hinge point between the upper torque arm and the rotating sleeve, Y 3k Indicates the distance between the upper torque arm and the rotating sleeve hinge point and the axle loading point in the Y direction, X 3k Indicates the distance between the hinge point of the upper torque arm and the rotating sleeve and the axle loading point in the X direction; The seventh equation is expressed as: ； In the formula, Y 23 Indicates the distance between the hinge point of the upper torque arm and the lower torque arm and the hinge point of the upper torque arm and the rotating sleeve in the Y direction, X 23 Indicates the distance between the hinge point of the upper torque arm and the lower torque arm and the hinge point of the upper torque arm and the rotating sleeve in the X direction; Based on the seven equations, the load condition of the simplified force system is obtained.

8. An electronic device, characterized in that: include: Controller; A memory for storing one or more programs, which, when executed by the controller, enables the controller to implement the topology optimization method for complex load conditions of an aircraft landing gear as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that: Computer-readable instructions are stored thereon, and when the computer-readable instructions are executed by a processor of a computer, the computer is caused to execute the topology optimization method for complex load conditions of an aircraft landing gear according to any one of claims 1 to 6.

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