A ribbed plate structure and a design method thereof

Abstract

The application discloses a rib lattice plate structure and a design method thereof, which takes into account bearing and thermal stress release, and belongs to the field of wall plate structures. The wall plate structure comprises a wall plate base body and rib lattice units distributed on the wall plate base body. The rib lattice units are connected with each other and form a continuous rib lattice network on the surface of the wall plate base body. The topological configuration, geometric parameters and spatial arrangement of the rib lattice network are adaptively adjusted according to the bearing and thermal stress release requirements of the region where the wall plate base body is located. Through the topological configuration and geometric parameters of the rib lattice network, the deep integration of the bearing structure and the thermal stress release function is realized, the contradiction between bearing and thermal deformation in the traditional design is overcome, the structural efficiency is improved, and the integrated design of bearing and thermal stress release is realized.

Description

Technical Field

[0001] This invention relates to the field of wall panel structure design technology for aerospace equipment, specifically to a ribbed grating structure and its design method that takes into account both load-bearing capacity and thermal stress relief. Background Technology

[0002] In aerospace and other fields, the wall panel structures of airframes, engine nacelles, and propulsion systems (such as air intakes and exhaust nozzles) face increasingly severe multi-physics coupled service environments involving force, heat, and sound. These structures not only need to act as load-bearing components, withstanding mechanical loads such as aerodynamic pressure and airframe loads to maintain precise aerodynamic shapes, but are also exposed to high-temperature environments caused by high-speed airflow and engine radiation. Under these conditions, traditional structural design methods face a structural design challenge: the contradiction between structural load-bearing capacity and thermal stress. To meet high load-bearing requirements, the stiffness of the structure must be increased, but this will strengthen the thermal expansion constraint of the material, leading to a significant increase in thermal stress. Conversely, if a flexible structure is designed to release the constraint in order to reduce thermal stress, its load-bearing capacity and stability will be weakened. This contradiction is particularly prominent when using homogeneous thin plates or traditional stiffened wall panels.

[0003] In the existing technology, the main ways to alleviate thermal stress include: (1) material approach, using high temperature alloys, ceramic matrix composites, etc., but the cost is high and the processability is limited; (2) thermal insulation approach, adding thermal insulation coatings or thermal insulation layers, but it will occupy space or relatively increase the weight; (3) structural approach, setting thermal expansion gaps, sliding supports, etc., but it will interrupt the main force transmission path, weaken the structural integrity, and may introduce sealing or vibration problems; In addition, traditional designs usually use homogeneous thin plates or regular stiffened plates, and rely on additional thermal insulation layers or reserved expansion gaps for thermal protection; This functional separation design mode leads to low structural efficiency, increased weight, and difficulty in effectively alleviating the local thermal stress concentration caused by the combined effect of material thermal expansion and boundary constraints, which can easily lead to structural buckling, fatigue or even failure.

[0004] With the development of advanced forming technologies such as additive manufacturing, it has become a reality to manufacture integrated lightweight structures with complex spatial topologies. However, there is currently a lack of systematic design methods to fully harness this manufacturing freedom and to integrate load-bearing performance and thermal deformation control capabilities through topological innovation in integrated collaborative design.

[0005] Therefore, there is an urgent need for an integrated grating structure and its design method that can adaptively adjust stiffness and thermal deformation capacity according to load and temperature field distribution, and can be deeply integrated with advanced manufacturing processes, so as to achieve synergistic optimization of load-bearing and thermal stress release functions. Summary of the Invention

[0006] To address the aforementioned shortcomings of existing technologies, this invention provides a stiffened lattice structure and its design method that balances load-bearing capacity and thermal stress release, enabling differentiated design of the structure's spatial stiffness and thermal deformation capacity, thereby achieving both high load-bearing efficiency and low thermal stress levels under high-temperature-mechanical coupling conditions.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, a ribbed panel structure that balances load-bearing capacity and thermal stress relief is provided. This structure is a wall panel structure, comprising: a wall panel substrate and ribbed units protruding and distributed on the wall panel substrate. The ribbed units are interconnected and form a continuous ribbed network on the surface of the wall panel substrate. The topology, geometric parameters, and spatial arrangement of the ribbed network are adaptively adjusted according to the load-bearing capacity and thermal stress relief requirements of the area where the wall panel substrate is located.

[0008] Furthermore, the geometric parameters of the lattice network include one or more of the cross-sectional shape, height, width, spacing, orientation, and network distribution density of the lattice elements.

[0009] Furthermore, the topology of the lattice network includes periodically arranged units, the cross-sectional shape of which is rectangular, trapezoidal, I-shaped, T-shaped, circular, sinusoidal, cap-shaped, or a custom-defined curved convex shape.

[0010] Furthermore, the spatial arrangement of the rib network on the wall panel substrate is either a periodic arrangement with equal density or a variable density grid arrangement with gradient changes.

[0011] Furthermore, the rib unit protrudes from one or both sides of the wall panel substrate.

[0012] Furthermore, the wall panel substrate and the rib grid unit are integrally formed structures.

[0013] Furthermore, the wall panel structure is made of metal or composite materials.

[0014] Secondly, a design method for a stiffened lattice structure that balances load-bearing capacity and thermal stress relief is provided, comprising the following steps: S1. Requirements and Operating Conditions Definition: Analyze and determine the mechanical load, temperature field distribution, and stiffness requirements of the target wall panel structure; S2. Rib grid network topology design: Plan the topology type and initial network layout of the rib grid units within the design domain of the wall panel substrate; S3. Parametric Modeling and Performance Design: Parametric modeling of the initial network layout is performed. Based on the requirements of step S1, the topology, geometric parameters and spatial arrangement of the rib grid units are adjusted in a differentiated manner to customize the stiffness and thermal stress release capability of the wall panel substrate in different directions. S4. Multiphysics Simulation and Iterative Optimization: Establish a thermo-mechanical coupling simulation model, evaluate the structural performance, and iteratively optimize the design parameters in step S3 based on the evaluation results. S5. Manufacturing Adaptability Adjustment and Output: Adjust the manufacturing process constraints of the optimized wall panel structure and output the final design model.

[0015] Furthermore, the differential adjustments in step S3 specifically include: In directions with high load-bearing requirements, the equivalent stiffness in that direction can be improved by increasing the moment of inertia of the stiffened grid elements, increasing their density, or using a more rigid cross-sectional shape. In directions where thermal stress needs to be released, controllable thermal deformation channels can be provided by optimizing the orientation of the rib grid elements or reducing the network connection stiffness. To improve out-of-plane stiffness, one can change the height of the cross-section protrusion, introduce other topological configurations based on the in-plane mesh, or add vertical components.

[0016] Furthermore, in step S4, a thermo-mechanical coupled finite element analysis is used for performance evaluation, and the optimization process includes parameter sensitivity analysis and multi-objective optimization.

[0017] The beneficial effects of this invention are as follows: 1. This scheme achieves a deep integration of load-bearing structure and thermal stress relief function through the topology and geometric parameter design of the rib grid network. It overcomes the contradiction between load-bearing and thermal deformation in traditional design, improves structural efficiency, and realizes the integrated design of load-bearing and thermal stress relief.

[0018] 2. This solution can differentiate and adjust the topology, geometric parameters and spatial arrangement of the ribbed network according to the mechanical load and temperature field distribution of the specific region, so as to achieve precise matching of anisotropic stiffness and thermal expansion coefficient, and realize customized performance design.

[0019] 3. This solution provides a complete design methodology from requirements analysis, topology selection, parametric design, simulation optimization to manufacturing adaptation, ensuring optimal overall performance of the structure under complex force-thermal environments. At the same time, this solution is applicable to advanced forming processes such as hot stamping, incremental forming, and additive manufacturing, and is particularly compatible with digital manufacturing technologies such as 3D printing, enabling efficient one-piece forming of complex ribbed structures.

[0020] 4. Compared with traditional stiffened wall panels, this solution has higher load-bearing efficiency, lower thermal stress peak and better thermal fatigue life under the same weight, and is particularly suitable for high reliability and lightweight applications such as aerospace, with significant improvement in overall performance. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. The above and other objects, features, and advantages of the present invention will become clearer through the accompanying drawings. The same reference numerals indicate the same parts in all the drawings. The drawings are not intentionally drawn to scale to actual dimensions; the focus is on illustrating the main points of the invention.

[0022] Figure 1 This is a three-dimensional schematic diagram of the grating in this design.

[0023] Figure 2 This is a plan view of the grating in this design.

[0024] Figure 3 for Figure 2 A cross-sectional view of region AA in the middle.

[0025] Figure 4 The diagrams show the structures of schemes 1-6.

[0026] Figure 5 The diagram shows the structure of 7-12 schemes and the baseline scheme.

[0027] Figure 6 This is a comparison chart of the relative deformations of the 12 schemes.

[0028] Figure 7 The diagram shows the stress distribution and deformation after performance adjustment.

[0029] Figure 8 A schematic diagram of the structure of the grating after adjustment and optimization.

[0030] Figure 9 This is a structural diagram of a rubber-reinforced grid panel.

[0031] Figure 10 This is a schematic diagram of a large-size integral fuselage rib plate structure.

[0032] Among them, 1. wall panel base, 2. rib grid unit. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0035] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0036] Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0037] like Figures 1 to 3 As shown, the ribbed panel structure of this scheme, which balances load-bearing capacity and thermal stress relief, is a wall panel structure, comprising: a wall panel base 1 and ribbed units 2 protruding from the wall panel base 1. The ribbed units 2 are interconnected and form a continuous ribbed network on the surface of the wall panel base 1. The topology, geometric parameters, and spatial arrangement of the ribbed network are adaptively adjusted according to the load-bearing capacity and thermal stress relief requirements of the area where the wall panel base 1 is located. Wherein, W is the width of the ribbed unit 2, H is the height of the ribbed unit 2, and D is the spacing between the ribbed units 2. θ Let be the tilt angle of the rib grid element 2, where ± θ D and W can affect the equivalent shear stiffness and equivalent thermal expansion coefficient of the stiffened grating; H can affect the equivalent normal stiffness of the stiffened grating.

[0038] In specific implementation, the geometric parameters of the ribbed network include one or more of the following: cross-sectional shape, height, width, spacing, orientation, and network distribution density of the ribbed unit 2; the topological configuration of the ribbed network includes periodically arranged units, and the cross-sectional shape of the units is rectangular, trapezoidal, I-shaped, T-shaped, circular, sinusoidal, cap-shaped, or a custom-defined curved protrusion; the spatial arrangement of the ribbed network on the wall panel substrate 1 is either a periodically arranged grid with equal density or a gradient-changing grid arrangement; the ribbed unit 2 protrudes from one or both sides of the wall panel substrate 1; the wall panel substrate 1 and the ribbed unit 2 are integrally formed structures; the wall panel structure is made of metal or composite materials.

[0039] The design process of a certain fuselage skin panel structure is given below: This solution targets the skin panel of a certain fuselage. Based on the analysis of its force transmission path, it mainly bears the shear force transmitted by the fuselage and is in a relatively uniform temperature field environment.

[0040] S1: Define Design Requirements: Based on the application location of the design object on the aircraft, analyze its load-bearing characteristics and define its design requirements; This embodiment belongs to the aircraft fuselage skin panel, which mainly bears the shear force generated by fuselage torque, the distributed aerodynamic load (i.e., out-of-plane normal load), and the thermal load generated by aerodynamic heat. It does not bear axial load, which is mainly borne by the longitudinal main load-bearing structure of the fuselage; Based on the application environment of the skin panel, the design goal of this panel is to have good shear stiffness or close to the shear stiffness of a flat plate, a certain normal stiffness, and to be able to withstand the distributed aerodynamic load without the normal deformation exceeding the overall requirements. In this embodiment, the aerodynamic load is set to 50 kPa; the ambient temperature is set to 200℃.

[0041] S2: Material Selection and Dimension Determination: Based on the arrangement of the longitudinal beams of the main load-bearing structure of the fuselage and the design object of the fuselage skin panels, the dimensions of the fuselage skin panels are determined. Furthermore, the local coordinate system of the fuselage skin panels is determined according to the aircraft coordinate system to clarify the equivalent stiffness of the fuselage skin panels in different directions, such as axial tensile and compressive stiffness. Since this is the exploration stage, it can be simplified to a flat plate. The dimensions of this embodiment are 840mm*640mm. The material selection of the panels is determined according to the application environment. Considering the load-bearing and temperature requirements, titanium alloy material is used in this embodiment.

[0042] S3: Conceptual Topology Selection: Based on the load-bearing characteristics of the skin panel, which mainly transmits shear loads, an orthogonal or oblique grid topology structure is proposed as the overall scheme for the skin panel. The grid unit cross-section is grooved, which enhances the normal stiffness of the panel on the one hand, and plays a role in releasing thermal stress on the other.

[0043] S4: Scheme Comparison and Selection: Based on the overall scheme and its derivative schemes proposed in step S3, other possible schemes are added, and the performance of all the above schemes is compared and selected. The selection method is to apply unit tensile / compressive load, unit shear load, unit normal uniformly distributed load, and 200℃ temperature load to all the above possible schemes respectively. Taking the total deformation of a plate of the same size under the above loads as the benchmark, the equivalent stiffness of the above possible schemes relative to the plate structure in different directions is calculated. The equivalent stiffness includes equivalent tensile / compressive stiffness, equivalent shear stiffness, equivalent normal stiffness, and equivalent thermal expansion deformation. The scheme that simultaneously possesses good equivalent shear stiffness, small equivalent tensile / compressive stiffness, certain equivalent normal stiffness, and small equivalent thermal expansion deformation is selected as the optimal scheme.

[0044] In practice, it includes: S41: Determining Possible Solutions: This embodiment proposes several possible solutions. One is based on the overall scheme of orthogonal or oblique meshes, proposing several refined schemes. Based on the overall scheme of the wall panel structure, this embodiment extracts typical features and designs a series of sample points according to the range of typical feature parameters. In this embodiment, for the topological structure of the oblique mesh, the typical feature parameters are the mesh deflection angle and the mesh spacing. Based on this, the proposed sample point structure schemes are 45°-60-15-7, 45°-80-15-7, 45°-100-15-7, 45°-120-15-7, 45°-140-15-7, 45°-160-15-7, 15°-100-15-7, 30°-100-15-7, 60°-100-15-7, 75°-100-15-7, (mesh deflection angle...). θ - Mesh spacing D - Mesh height H - Mesh cell groove width W), Additionally, several other possible solutions are provided: a broken-rib design and a corrugated plate design; a total of 12 possible solutions; the structural diagrams for the 12 solutions are shown below. Figure 4 and Figure 5 As shown.

[0045] S42: Equivalent stiffness analysis of all possible solutions: Numerical simulation models were established for each of the above schemes. Unit tensile or compressive loads, unit shear loads, unit uniformly distributed normal loads, and 200℃ were applied individually. The total deformation of each structural scheme under each load was obtained through numerical simulation, namely the total tensile and compressive deformation under tensile and compressive loads, the total shear deformation under shear loads, the total normal deformation under uniformly distributed normal loads, and the normal deformation at 200℃. At the same time, based on the mechanical properties of the plate structure, a numerical simulation model of the plate was established. Through analysis, the total tensile and compressive deformation under tensile and compressive loads, the total shear deformation under shear loads, the total normal deformation under uniformly distributed normal loads, and the normal deformation at 200℃ were obtained. Based on the total deformation of the plate, the relative deformation of all the above possible schemes was obtained to reflect the equivalent stiffness characteristics of the relative plate performance.

[0046] S43: Scheme selection: Scheme selection is carried out from two aspects, namely based on equivalent stiffness and thermal stress distribution.

[0047] Based on equivalent stiffness: According to the formula "relative equivalent stiffness = 1 / relative deformation", the optimal solution can be selected based on the comparison of relative deformation. The selection criteria are: large relative equivalent shear stiffness, small relative equivalent tensile / compressive stiffness, large relative equivalent normal stiffness, and small relative normal deformation due to thermal expansion. A comparison of relative deformation is shown in the diagram. Figure 6As shown in the figure; the abscissa in the figure represents 12 schemes, and the four curves represent the relative deformation of the 12 schemes under a certain load; it can be seen from the figure that the optimal scheme selected is Scheme 7, that is, the relative equivalent tensile-compressive stiffness is small, the relative equivalent shear stiffness is large, the relative equivalent normal stiffness is large, and the thermal expansion relative to the normal deformation is small; the structural form of Scheme 7 is 75°-100-15-7.

[0048] Based on the thermal stress release effect: In this embodiment, by comparing the thermal stress distributions of the above 12 schemes at a temperature of 200 °C, the better schemes are selected, and the maximum stress without boundary influence, the average stress of the ribs on the rib grid, the average stress of the grid cells of the rib grid, etc. are compared respectively; through comparison, the scheme with a lower thermal stress level is selected as the optimal scheme, which is also the 75°-100-15-7 scheme.

[0049] S5: Performance adjustment: Through appropriate adjustment, reinforce its performance; in this embodiment, by analyzing the preferred scheme, it is found that the overall normal deformation is relatively large under the action of uniform normal aerodynamic load, so the normal stiffness is insufficient, and the design needs to be adjusted to enhance its normal stiffness; the method adopted in this embodiment is to reduce the size of the rib grid plate and at the same time increase the moment of inertia of the cross-section to enhance its normal stiffness; therefore, several improved schemes are proposed based on the above preferred scheme, namely the "day" grid, "field" grid, and "eye" grid schemes. The geometric shapes, stress distributions, and deformation conditions of the above schemes are as Figure 7 shown; it can be seen that the normal deformation of the initial preferred scheme is 17.6 mm. Through the improvement of different schemes, the normal deformation is decreasing. The final improved scheme is the "eye" grid scheme, and the structural parameters of the "eye" grid scheme are adjusted and optimized. Finally, the maximum normal deformation of the rib grid plate structure is 5.94 mm, meeting the design requirements of the normal stiffness; therefore, the structural form and structural parameters of the scheme are determined, as shown in Figure 8 shown.

[0050] S6: Structural parameter adjustment considering manufacturing process: S61: Since the scheme proposed in step S5 is not convenient for processing, it is necessary to make adjustments adapted to the processing technology; that is, chamfer the right angles on the structure and determine the structural parameters that meet the processing requirements.

[0051] S62: Since the thermal stamping processing technology is adopted in this embodiment, a process simulation analysis software is used to perform process simulation analysis on the structural scheme determined in step S61 to determine the thickness distribution of the skin panel structure after processing and manufacturing and the overall deformation after processing.

[0052] S63: Evaluate the above simulation results to evaluate whether the thickness distribution and processing deformation affect the use of the structure itself; in this embodiment, according to the processing technology requirements, the final structural scheme after adjustment is as Figure 9 shown.

[0053] In addition, such as Figure 10 As shown, to simplify the structural form and reduce the structural weight, its large-size, modular design has advantages such as quick disassembly, replacement, and convenient maintenance. The fuselage skin panels of this solution are large-size integral panels, which are connected to the main load-bearing structure of the fuselage through a quick disassembly and assembly method, thereby realizing the rapid assembly and replacement of the entire fuselage skin panel structure to meet the requirements of the top layer of the aircraft. The entire fuselage panel is assembled from several large-size integral panels, and the size of each panel is determined by the arrangement of the main load-bearing components of the fuselage. The large-size integral panels are installed on the main load-bearing structural components of the fuselage through quick connection structures / mechanisms.

[0054] Although the specific embodiments of the invention have been described in detail with reference to the accompanying drawings, this should not be construed as limiting the scope of protection of this patent; various modifications and variations that can be made by a person skilled in the art without inventive effort within the scope described in the claims are still within the scope of protection of this patent.

Claims

1. A ribbed panel structure that balances load-bearing capacity and thermal stress relief, being a wall panel structure, characterized in that, include: The wall panel substrate and the rib grid units protruding on the wall panel substrate are interconnected and form a continuous rib grid network on the surface of the wall panel substrate; the topology, geometric parameters and spatial arrangement of the rib grid network are adaptively adjusted according to the load-bearing and thermal stress release requirements of the area where the wall panel substrate is located. The geometric parameters of the ribbed network include one or more of the following: cross-sectional shape, height, width, spacing, orientation, and network distribution density of the ribbed elements. The topology of the lattice network includes periodically arranged units, and the cross-sectional shape of the units is rectangular, trapezoidal, I-shaped, T-shaped, circular, sinusoidal, cap-shaped, or a custom-defined curved convex shape. The rib network is arranged in a periodic arrangement with equal density or a variable density grid arrangement with gradient variation on the wall panel substrate. In directions with high load-bearing requirements, the equivalent stiffness in that direction can be improved by increasing the moment of inertia of the stiffened grid elements, increasing their density, or using a more rigid cross-sectional shape. In directions where thermal stress needs to be released, controllable thermal deformation channels can be provided by optimizing the orientation of the rib grid elements or reducing the network connection stiffness. To improve out-of-plane stiffness, the height of the cross-section protrusions is changed, and other topological configurations are introduced on the basis of the in-plane mesh.

2. The ribbed lattice structure that combines load-bearing capacity and thermal stress relief according to claim 1, characterized in that, The rib unit protrudes from one or both sides of the wall panel substrate.

3. The ribbed lattice structure that combines load-bearing capacity and thermal stress relief according to claim 1, characterized in that, The wall panel base and the rib grid unit are integrally formed structures.

4. The ribbed grating structure that combines load-bearing capacity and thermal stress relief according to claim 1, characterized in that, The wall panel structure is made of metal or composite materials.

5. A design method for a stiffened lattice structure that combines load-bearing capacity and thermal stress relief as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Requirements and Operating Conditions Definition: Analyze and determine the mechanical load, temperature field distribution, and stiffness requirements of the target wall panel structure; S2. Rib grid network topology design: Plan the topology type and initial network layout of the rib grid units within the design domain of the wall panel substrate; S3. Parametric Modeling and Performance Design: Parametric modeling of the initial network layout is performed. Based on the requirements of step S1, the topology, geometric parameters and spatial arrangement of the rib grid units are adjusted in a differentiated manner to customize the stiffness and thermal stress release capability of the wall panel substrate in different directions. S4. Multiphysics Simulation and Iterative Optimization: Establish a thermo-mechanical coupling simulation model, evaluate the structural performance, and iteratively optimize the design parameters in step S3 based on the evaluation results. S5. Manufacturing Adaptability Adjustment and Output: Adjust the manufacturing process constraints of the optimized wall panel structure and output the final design model.

6. The design method according to claim 5, characterized in that, In step S4, a thermo-mechanical coupled finite element analysis is used for performance evaluation. The optimization process includes parameter sensitivity analysis and multi-objective optimization.

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