Special-shaped structure optimization design method based on additive manufacturing

Abstract

The invention discloses a special-shaped structure optimization design method based on additive manufacturing, and the method is characterized in that the method comprises the following steps: S1, designing and obtaining an optimization space model of a special-shaped structure; s2, adding material attributes to the design space model, considering a gravity environment and a full-period load environment of the special-shaped structure, fixing constraints, and applying a load according to a load condition; s3, target lightweight optimization analysis is completed; s4, according to an optimization result, completing model reconstruction by utilizing a reconstruction module, and performing structural performance analysis on the reconstructed model through a structural performance analysis module to verify related performance indexes of the model; and S5, the special-shaped part is manufactured, three-dimensional scanning of the manufactured special-shaped part entity is completed through the three-dimensional scanning technology, and comparison and analysis of size and form and position deviation are conducted on the scanning result and the design model so as to check whether the special-shaped part meets the design requirement or not. According to the invention, the design and inspection requirements of rapid structure, high performance, integration and light weight based on additive manufacturing are met.

Description

Technical Field

[0001] The present invention relates to the field of aerospace equipment installation, and in particular to an optimization design method for special-shaped structures based on additive manufacturing. Background Art

[0002] In the aerospace field, the equipment installation structure is used to connect the equipment with the main structure of the cabin, and ensures a certain rigidity and strength in the active launch section to ensure the safety of the equipment. With the increasingly strong demand for high performance of products in the aerospace field, the weight of aircraft parts has become an important factor affecting the performance and benefits of the entire aircraft. The rapid, efficient and lightweighting of aircraft parts can not only significantly improve the performance of the product and break through certain technical bottlenecks, but also reduce the consumption of energy resources during the production and processing of parts and subsequent service, and achieve an all-round upgrade of the performance of the final product.

[0003] The existing lightweight optimization design methods for complex parts usually have multiple parts, increased overall manufacturing time and overall manufacturing costs, and it is difficult to meet the different performance requirements of each part. The development of emerging processes such as additive manufacturing has reduced the manufacturing restrictions on special-shaped topological optimization structures. The field expects a special-shaped structure optimization design method based on additive manufacturing, which can achieve high-performance integrated design of the structure and lightweight structure at the same time. Summary of the invention

[0004] The purpose of the present invention is to provide a special-shaped structure optimization design method based on additive manufacturing to meet the requirements of fast, high-performance, integrated and lightweight design and inspection of special-shaped structures based on additive manufacturing.

[0005] Specifically, the present invention provides a method for optimizing the design of special-shaped structures based on additive manufacturing, which is characterized by comprising the following steps:

[0006] S1. Using a three-dimensional modeling module or CAD software, design and obtain an optimized spatial model of the special-shaped structure;

[0007] S2, add material properties to the design space model, consider the gravity environment and the full-cycle load environment of the special-shaped structure, fix the constraints and apply the load according to the load conditions;

[0008] S3. Complete the target lightweight optimization analysis according to the minimum mass method or maximum stiffness method as the optimization target;

[0009] S4. Based on the optimization results, the reconstruction module is used to complete the model reconstruction. The structural performance analysis module is used to analyze the structural performance of the reconstructed model to verify its relevant performance indicators. When reconstructing the model, rounded arc transition is used to avoid the angle between the overhanging structure and the horizontal plane being greater than 45°, and thin-walled structures and small hole structures are avoided;

[0010] S5. After the special-shaped structure is verified and qualified, the special-shaped parts are obtained based on additive manufacturing according to the reconstructed model. The three-dimensional scanning of the manufactured special-shaped parts is completed through three-dimensional scanning technology, and the scanning model and data are obtained. The scanning results of different parts of the special-shaped parts are compared with the design model for size and shape deviation analysis to check whether the special-shaped parts meet the design requirements.

[0011] Furthermore, the thin-walled structure in step S4 refers to a surface structural feature with a ratio of height to wall thickness greater than 40, and is thus designed so that the wall thickness ≮0.5 mm and the pore diameter ≮1 mm.

[0012] Furthermore, the deviation comparison analysis based on the scanning result and the design model in step S5 includes: agreeing on a reference R-hole reference coordinate system for the special-shaped part, selecting a reference reference plane for the special-shaped part, making a section of the part every 20 to 30 mm along the normal direction of this plane, selecting 10 to 15 points for each independent section in the section, connecting all the above points with the agreed reference R-hole coordinate system, and taking the projection dimensions in three directions of the R-hole coordinate system as measurement data, obtaining the dimension data of all points to the R-hole coordinate system in the three directions of X, Y, and Z, and performing dimensional deviation analysis on the data obtained by the same method with the three-dimensional design model, and using the dimensional deviation to determine whether the special-shaped part meets the design requirements.

[0013] Furthermore, the step S1 includes: confirming the layout status of the device connected to the special-shaped structure, the layout status includes the device layout installation position, layout polarity, confirming the available space of the special-shaped structure, mainly completing the interference check with the surrounding devices or structures, confirming the correctness of the connection interface between the special-shaped structure and the main structure and the connected device, and then using a three-dimensional modeling module or CAD software to complete the design of the available space model of the special-shaped structure to obtain the optimized space model of the special-shaped structure, and the layout polarity includes the field of view that needs to be confirmed by the optical or measurement and control facilities, and the plume effect that needs to be confirmed by the engine.

[0014] Furthermore, step S2 includes: adding material properties to the design space model, setting the gravity direction based on the X, Y, and Z directions of the coordinate system of the special-shaped structure, setting a concentrated mass point on the special-shaped structure, fixing constraints and applying overloads in various directions according to the coordinate system.

[0015] Furthermore, step S3 includes: setting the minimum value of the fundamental frequency of the part, the thickness, and the minimum safety factor, and completing the target lightweight optimization analysis according to the minimum mass method as the optimization target, that is, the part obtains the lightest mass while meeting the minimum stiffness; or under the maximum stiffness principle, in order to obtain the minimum mass under the condition of maximum stiffness, the percentage of the inherent volume of the optimized space model is used as the optimization target, and the minimum value of the fundamental frequency of the part and the thickness are set at the same time to complete the target lightweight optimization analysis.

[0016] Furthermore, the special-shaped structure is an equipment installation bracket, and the device connected to the special-shaped structure is a main structure and the equipment to be installed.

[0017] Furthermore, in step S5, the measured dimensional deviation is judged to be qualified according to GB / T1804-m standard.

[0018] Furthermore, the dimensional deviations of the X, Y, and Z dimensions of all points to the R-hole coordinate system in three directions should comply with the GB / T1804-m standard.

[0019] Furthermore, in step S3, the lower limit of the fundamental frequency of the component is 100 Hz.

[0020] The beneficial effects of the present invention are:

[0021] The special-shaped structure optimization design method based on additive manufacturing of the present invention takes into account the characteristics of additive manufacturing, and incorporates a new inspection method for special-shaped structure products, providing a design method that meets the requirements of high performance, integration, lightweight and rapidity based on additive manufacturing. In this method, the minimum mass method is used as the optimization target, and the minimum fundamental frequency and minimum safety factor of the parts are set to ensure lightweight design that meets performance requirements. Based on the additive manufacturing process, it is proposed that arc transitions should be used in structural design to avoid overhang structures with an angle greater than 45° with the horizontal plane, thin-walled structures (surface structures with a height to wall thickness ratio greater than 40 are called thin-walled structures, and the wall thickness is not less than 0.5mm) and small hole structures (not less than 1mm); in addition, a new inspection method for special-shaped structure products is proposed to realize the acceptance of the size and shape deviation of the mounting surface, mounting holes and intermediate structures of special-shaped parts.

[0022] The additive manufacturing-based special-shaped structure optimization design method of the present invention realizes rapid, integrated, lightweight design and verification of the effectiveness of the special-shaped structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The figure is a flow chart of a preferred embodiment of the present invention.

[0024] Figure 2 It is a schematic diagram of the implementation of a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0025] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

[0026] The present invention discloses a method for optimizing the design of special-shaped structures based on additive manufacturing. The method utilizes a three-dimensional modeling module (or CAD software) to complete the design of the optimization space, obtain a model of the optimization space of the special-shaped structure, add material properties to the design space model, consider the gravity environment and the full-cycle load environment of the bracket, complete the setting of constraint conditions and load conditions, take the minimum mass method or the maximum stiffness method as the optimization target, complete the target lightweight optimization analysis, and according to the optimization result, use a reconstruction module to complete the model reconstruction, use a structural performance analysis module to perform structural performance analysis on the reconstructed parts to verify their relevant performance indicators, and use a three-dimensional scanning technology to complete the three-dimensional scanning analysis of the special-shaped parts manufactured by additive manufacturing, obtain the scanning model and data, and compare the scanning results of different parts of the special-shaped parts with the design model to analyze the size and shape deviations to check whether the special-shaped parts meet the design requirements.

[0027] The present invention meets the requirements for rapid, high-performance, integrated, and lightweight design and inspection of special-shaped structures based on additive manufacturing.

[0028] Specifically, the method for optimizing the design of special-shaped structures based on additive manufacturing of the present invention adopts a technical solution comprising the following steps:

[0029] S1. Using a three-dimensional modeling module (or CAD software), design and obtain an optimized spatial model of a special-shaped structure, wherein the special-shaped structure is used to connect the main structure and the connected device;

[0030] Specifically, confirm the layout status of the device connected to the special-shaped structure, which includes the device layout installation position, layout polarity (optical or measurement and control facilities need to confirm the field of view, and the engine needs to confirm the plume impact), confirm the available space of the special-shaped structure, mainly complete the interference check with the surrounding devices or structures, confirm the correctness of the connection interface between the special-shaped structure and the main structure and the connected device, and then use the three-dimensional modeling module (or CAD software) to complete the design of the available space model of the special-shaped structure to obtain the optimized space model of the special-shaped structure.

[0031] In one embodiment, the special-shaped structure is a mounting bracket for a certain type of measurement and control equipment, and the device connected to the special-shaped structure is the main structure and the equipment to be installed. Considering the spatial position of the two mounting surfaces with the main structure and the one connection surface with the equipment to be installed, and considering the maximum available envelope that does not interfere with the surrounding thermal control radiators and other equipment, the optimized spatial model of the bracket is designed using Pro / E. The equipment to be installed connected to the special-shaped structure is the directional antenna of the measurement and control subsystem. At this time, the layout position of the equipment confirms the layout polarity as the field of view analysis of the antenna, and the field of view is not blocked by the surrounding equipment.

[0032] S2, add material properties to the design space model, consider the gravity environment and the full-cycle load environment of the special-shaped structure, fix the constraints and apply the load according to the load conditions;

[0033] Specifically, material properties are added to the design space model, the gravity direction is set based on the X, Y, and Z directions of the coordinate system of the special-shaped structure, a concentrated mass point is set on the special-shaped structure, constraints are fixed, and overloads are applied in various directions according to the coordinate system.

[0034] In one embodiment, when the special-shaped structure is a device mounting bracket, the concentrated mass point is set at the far end of the mounting hole on one side of the bracket. According to the calculation and analysis requirements, reasonable constraints on movement and rotation in different directions are set. For example, fixed constraints are set for 10 mounting holes on the bottom mounting surface of a certain bracket, and point loads, line loads or surface distributed loads are set at appropriate positions. For example, an overload of 10g in each direction is set at the concentrated mass point of a certain bracket.

[0035] S3. Complete the target lightweight optimization analysis according to the minimum mass method or maximum stiffness method as the optimization target;

[0036] Specifically, the minimum value of the fundamental frequency of the part, the thickness, and the minimum safety factor are set, and the target lightweight optimization analysis is completed according to the minimum mass method as the optimization goal. That is, the part obtains the lightest mass while meeting the minimum stiffness.

[0037] The maximum stiffness method mainly refers to the fundamental frequency of the parts meeting certain requirements. Under the maximum stiffness principle, in order to obtain the minimum mass under the condition of maximum stiffness, the percentage of the inherent volume of the optimized space model is used as the optimization target (the percentage of volume represents the value of a mass), and the minimum value of the fundamental frequency of the parts, thickness, etc. are set at the same time, and the target lightweight optimization analysis is completed.

[0038] In one embodiment, the minimum mass method is used as the optimization target, and the stiffness index of the part is taken into consideration. The lower limit of the fundamental frequency of the part is preferably 100Hz. If it is set too high, the weight will increase significantly. If it is set too low, the stiffness requirement of the task cannot be met. The thickness setting can be made according to actual needs, for example, it can be set to 4mm. The thinner the thickness, the longer the calculation time required to achieve the expected stiffness with the minimum mass, so it is usually necessary to consider these situations and set it reasonably. The minimum safety factor can be set as needed, for example, it can be set to 1.5 times.

[0039] S4. Based on the optimization results, the reconstruction module is used to complete the model reconstruction, and the structural performance analysis module is used to perform structural performance analysis on the reconstructed model to verify its relevant performance indicators;

[0040] Taking into account the characteristics of the additive manufacturing process, when reconstructing the model, try to use rounded arc transitions, avoid overhanging structures with an angle greater than 45° with the horizontal plane, avoid thin-walled structures (surface structures with a height to wall thickness ratio greater than 40 are called thin-walled structures, so that the wall thickness ≮0.5mm) and small hole structures (so that the hole diameter ≮1mm).

[0041] The processing angle is 90° (forming direction), which can obtain the best forming accuracy and surface accuracy. If the forming angle of the designed part is not greater than 45°, the forming angle is between 30° and 45°, or even less than 30°, as the processing angle deviates from the processing direction, the processing processability of the structure deteriorates, and it is easy to form collapse, slag, serious warping deformation and forming failure, and the surface roughness of the processed surface will deteriorate.

[0042] S5. After the special-shaped structure is verified and qualified, the special-shaped part is obtained based on additive manufacturing according to the reconstructed model, and the three-dimensional scanning of the manufactured special-shaped part is completed by three-dimensional scanning technology, and the scanning model and data are obtained. The scanning results of different parts of the special-shaped part are compared with the design model for size and shape deviation to check whether the special-shaped part meets the design requirements. Due to the special structure of special-shaped parts, it is impossible to perform comparative analysis through conventional technical measurements. Therefore, the inventors have designed a new analysis and comparison method based on three-dimensional scanning technology. Specifically, the deviation comparison analysis between the scanning results and the design model includes the following steps:

[0043] The reference R-hole datum coordinate system is agreed upon for special-shaped parts, and the datum reference plane of the special-shaped parts is selected. The parts are sectioned every 20 to 30 mm along the normal direction of this plane. 10 to 15 points are selected for each independent section in the section. All the above points are connected with the agreed datum R-hole coordinate system, and the projection dimensions in three directions of the R-hole coordinate system are used as measurement data. The dimensional data of all points to the R-hole coordinate system in the X, Y, and Z directions are obtained, and the dimensional deviation analysis is performed with the data obtained by the same method with the 3D design model to determine whether the special-shaped parts meet the design requirements.

[0044] In one embodiment, the special-shaped part is a bracket, and the mounting surface of the bracket and the main structure (or the equipment) is used as the reference surface. The part is cut every 20 to 30 mm along the normal direction of this surface. 10 to 15 points are selected for each independent section in the section. All the above points are connected to the agreed reference R-hole coordinate system, and the projection dimensions in three directions of the R-hole coordinate system are used as measurement data. The measurement data and the data obtained by the same method from the designed three-dimensional model are analyzed for dimensional deviation. The dimensional deviation should comply with the GB / T1804-m standard, and the dimensional deviations of all points to the X, Y, and Z dimensions of the R-hole coordinate system in three directions should comply with the standards specified above.

[0045] The following will be combined Figure 1 and Figure 2 The preferred embodiments of the present invention are described in further detail.

[0046] Figure 1 The present invention provides a design method for optimizing special-shaped structures based on additive manufacturing, which optimizes space design, sets safety boundary constraints, takes frequency index and minimum mass as optimization targets, and uses a model reconstruction module to quickly generate lightweight special-shaped brackets for 3D printing.

[0047] like Figure 1 As shown, the special-shaped structure optimization design method based on additive manufacturing of the present invention is carried out in the following steps:

[0048] (1) Determine the design domain, build the optimization space model, and define the design and non-design spaces;

[0049] (2) Add material properties to the spatial model, clarify load constraints, and set them according to the most stringent working conditions;

[0050] (3) Optimize the design with frequency and minimum mass as the objective function;

[0051] (4) Optimize the solution, read the results, and perform model reconstruction and strength and stiffness verification;

[0052] (5) Perform 3D scanning analysis on the physical parts manufactured by additive manufacturing and conduct deviation analysis with the design model to determine whether the requirements are met.

[0053] Figure 2 Schematic diagram of the implementation of the preferred embodiment of the present invention. The specific operation process of the present invention is as follows Figure 2 shown.

[0054] The embodiments of the present invention described above are only used to help explain the present invention. These embodiments are selected and specifically described in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and changes can be made according to the content of this specification, which all belong to the protection scope of the present invention.

Claims

1. A method for optimizing the design of special-shaped structures based on additive manufacturing, characterized in that: The steps include: S1. Using a three-dimensional modeling module or CAD software, design and obtain an optimized spatial model of the special-shaped structure; S2, add material properties to the design space model, consider the gravity environment and the full-cycle load environment of the special-shaped structure, fix the constraints and apply the load according to the load conditions; S3. Complete the target lightweight optimization analysis according to the minimum mass method or maximum stiffness method as the optimization target; S4. Based on the optimization results, the reconstruction module is used to complete the model reconstruction. The structural performance analysis module is used to analyze the structural performance of the reconstructed model to verify its relevant performance indicators. When reconstructing the model, rounded arc transition is used to avoid the angle between the overhanging structure and the horizontal plane being greater than 45°, and thin-walled structures and small hole structures are avoided; S5. After the special-shaped structure is verified and qualified, the special-shaped parts are obtained based on additive manufacturing according to the reconstructed model. The three-dimensional scanning of the manufactured special-shaped parts is completed through three-dimensional scanning technology, and the scanning model and data are obtained. The scanning results of different parts of the special-shaped parts are compared with the design model for size and shape deviation analysis to check whether the special-shaped parts meet the design requirements.

2. The method for optimizing the design of special-shaped structures based on additive manufacturing according to claim 1, characterized in that: The thin-walled structure in step S4 refers to a surface structural feature with a ratio of height to wall thickness greater than 40, so the design makes the wall thickness ≮0.5 mm and the pore diameter ≮1 mm.

3. The method for optimizing the design of special-shaped structures based on additive manufacturing according to claim 1, characterized in that: The deviation comparison analysis based on the scanning result and the design model in step S5 includes: agreeing on a reference R-hole reference coordinate system for the special-shaped part, selecting a reference reference plane for the special-shaped part, making a section of the part every 20 to 30 mm along the normal direction of this plane, selecting 10 to 15 points for each independent section in the section, connecting all the above points with the agreed reference R-hole coordinate system, and taking the projection dimensions in three directions of the R-hole coordinate system as measurement data, obtaining the dimension data of all points to the R-hole coordinate system in three directions of X, Y, and Z, and performing a dimension deviation analysis with the data obtained by the same method with the three-dimensional design model, and judging whether the special-shaped part meets the design requirements by the dimension deviation.

4. The method for optimizing the design of special-shaped structures based on additive manufacturing according to claim 1, characterized in that: The step S1 includes: confirming the layout status of the device connected to the special-shaped structure, the layout status includes the device layout installation position, layout polarity, confirming the available space of the special-shaped structure, mainly completing the interference check with the surrounding devices or structures, confirming the correctness of the connection interface between the special-shaped structure and the main structure and the connected device, and then using a three-dimensional modeling module or CAD software to complete the design of the available space model of the special-shaped structure to obtain the optimized space model of the special-shaped structure. The layout polarity includes the field of view that needs to be confirmed by the optical or measurement and control facilities, and the plume influence that needs to be confirmed by the engine.

5. The method for optimizing the design of special-shaped structures based on additive manufacturing according to claim 1, characterized in that: The step S2 includes: adding material properties to the design space model, setting the gravity direction based on the X, Y, and Z directions of the coordinate system of the special-shaped structure, setting a concentrated mass point on the special-shaped structure, fixing constraints, and applying overloads in various directions according to the coordinate system.

6. The method for optimizing the design of special-shaped structures based on additive manufacturing according to claim 1, characterized in that: The step S3 includes: setting the minimum value of the fundamental frequency of the part, the thickness, and the minimum safety factor, and completing the target lightweight optimization analysis according to the minimum mass method as the optimization target, that is, the part obtains the lightest mass while satisfying the minimum stiffness; or under the maximum stiffness principle, in order to obtain the minimum mass under the condition of maximum stiffness, the percentage of the inherent volume of the optimized space model is used as the optimization target, and the minimum value of the fundamental frequency of the part and the thickness are set at the same time to complete the target lightweight optimization analysis.

7. The method for optimizing the design of special-shaped structures based on additive manufacturing according to claim 1, characterized in that: The special-shaped structure is an equipment installation bracket, and the device connected to the special-shaped structure is a main structure and equipment to be installed.

8. The method for optimizing the design of special-shaped structures based on additive manufacturing according to claim 3, characterized in that: In step S5, the measured dimensional deviation is judged to be qualified according to the GB / T1804-m standard.

9. The method for optimizing the design of special-shaped structures based on additive manufacturing according to claim 8, characterized in that: The dimensional deviations of the X, Y and Z dimensions of all points to the R hole coordinate system in three directions shall comply with the GB / T1804-m standard.

10. The method for optimizing the design of special-shaped structures based on additive manufacturing according to claim 8, characterized in that: In step S3, the lower limit of the fundamental frequency of the component is 100 Hz.

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