CN-122020875-A - Additive manufacturing double-layer cylinder structure and modeling method thereof

CN122020875ACN 122020875 ACN122020875 ACN 122020875ACN-122020875-A

Abstract

The invention relates to a double-layer cylinder structure for additive manufacturing and a modeling method thereof, belongs to the field of additive manufacturing, and aims to solve the problems that when a traditional integral topology optimization design double-layer cylinder structure is adopted, the optimization efficiency is low due to huge calculation scale, and the lightweight performance of the structure, the feasibility of an additive manufacturing process and the integral regularity are difficult to synchronously guarantee. The structure comprises an inner sleeve, an outer sleeve and a sandwich structure formed by a periodic array of topological optimization units therebetween, wherein the units are provided with connecting walls and symmetrical supporting frameworks which are obtained through multi-constraint synchronous optimization. The modeling method generates the structure through parameterized input, unit division, multi-constraint synchronous optimization, array and integral iteration steps. The invention realizes high-efficiency design and directly manufactures the regularized double-layer cylinder structure with light weight, high bearing capacity and excellent manufacturability, and remarkably improves the design efficiency and the comprehensive performance of products.

Inventors

SU JIANGZHOU
HAN WEIQUN
WANG ZHIMIN
WANG YIMENG
CHE LEI
WANG YUJIAN
YANG CHENG
ZHAO WENZHENG
JIA XU
LI PENG

Assignees

北京航星机器制造有限公司

Dates

Publication Date: 20260512
Application Date: 20251229

Claims (10)

1. The additive manufacturing double-layer cylinder structure is characterized by comprising an inner sleeve (1), an outer sleeve (2) and a sandwich structure (3) which are coaxially arranged; The sandwich structure (3) is composed of a plurality of topological optimization units which are periodically arrayed in the circumferential direction and the axial direction; Each topology optimization unit is a sector block and comprises an inner connecting wall (7) connected with the outer wall of the inner sleeve (1), an outer connecting wall (8) connected with the inner wall of the outer sleeve (2), and a filling structure (6) connected between the inner connecting wall (7) and the outer connecting wall (8).
2. Additive manufacturing double-layer cylinder structure according to claim 1, characterized in that the filling structure (6) is an integrated supporting framework (9), and the included angle between the outer surface of the supporting framework (9) and the vertical direction of the additive manufacturing is not smaller than a preset minimum self-forming angle θ min .
3. Additive manufacturing double-layer cylinder structure according to claim 2, characterized in that the supporting framework (9) is in an X-shaped cross supporting configuration and comprises a main bearing rib (9-1) extending along the radial direction of the sector block and at least one pair of auxiliary bearing ribs (9-2) extending from the main bearing rib (9-1) symmetrically and obliquely, and the joint of the main bearing rib (9-1) and the auxiliary bearing rib (9-2) and the joint of the inner connecting wall (7) and the outer connecting wall (8) are provided with transition fillets (11).
4. Additive manufacturing double-layer cartridge structure according to claim 2, wherein the supporting skeleton (9) is in a tree topology configuration, comprising a main bearing rib (9-1) extending axially along the segment, and a plurality of auxiliary bearing ribs (9-2) extending symmetrically and obliquely from the main bearing rib (9-1) and connected to the inner and outer engagement walls (7, 8), respectively.
5. An additive manufacturing double-layer cylinder structure according to any one of claims 1 to 4, wherein the topological optimization unit has an axial height d/b, a circumferential outer arc length 2 pi R/a, and satisfies the constraint that d/b is equal to or greater than 2 pi R/a, wherein d is the axial length of the double-layer cylinder, R is the outer radius of the outer sleeve (2), a is the number of circumferential arrays, and b is the number of axial arrays.
6. A additive manufactured double layer cartridge structure according to any of claims 1-3, characterized in that the sandwich structure (3) has no completely closed cavities inside or that the existing closed cavities are provided with dust or dust removal holes.
7. A parametric modeling method for generating the additive manufactured dual layer cartridge structure of any one of claims 1-6, comprising the steps of: Inputting an inner radius R, an outer radius R and an axial length d of the double-layer cylinder structure, setting the corresponding areas of the inner sleeve (1) and the outer sleeve (2) as non-design areas, and setting the area between the inner sleeve and the outer sleeve as design areas for generating the sandwich structure (3); Step 2, dividing the design domain into a multiplied by b identical sector unit matrixes based on a preset circumferential division number a and an axial division number b; step 3, unit constraint topology optimization, namely performing topology optimization calculation aiming at the single fan-shaped unit matrix by taking the material volume minimization as a target, and synchronously applying the following constraint conditions in the optimization process: a) Functional constraint, namely applying working condition load and limiting that the maximum stress of the optimized structure does not exceed the allowable stress of the material and/or the maximum displacement does not exceed an allowable value; b) Defining the included angle between the normal vectors of all surfaces of the optimized structure and the vertical additive manufacturing direction to be not smaller than the minimum self-forming angle theta min ; c) Geometric symmetry constraint, namely enabling the unit structure obtained after optimization to be symmetrical in the fan-shaped unit matrix about at least one coordinate plane; step 4, array modeling, namely carrying out array on the unit structure obtained through optimization in the step 3 according to the circumferential segmentation quantity a and the axial segmentation quantity b, and generating a complete digital model of the sandwich structure (3) through Boolean union operation; And 5, integrally verifying and iterating, namely checking mechanical properties of an integral digital model comprising the sandwich structure (3), the inner sleeve (1) and the outer sleeve (2), outputting a final structural model if a checking result meets design requirements, and otherwise, returning to the step 3 to adjust optimization parameters or returning to the step 2 to adjust segmentation parameters a and b to perform iterative design.
8. The parametric modeling method of claim 7, wherein the geometric symmetry constraint in step3 is specifically that the optimized cell structure is symmetric about the XZ plane and the XY plane of the fan-shaped cell matrix.
9. A design method of a lightweight double-layer cylinder structure is characterized by comprising the steps of dividing a design domain and a non-design domain, dividing the design domain into periodic minimum units for topology optimization, combining an optimized design domain unit array and a non-design domain unit array to form an integral structure, performing strength check on the integral structure, and returning to adjust optimization parameters or unit structures to perform iterative optimization if a check result does not meet design requirements.
10. The method of claim 9, further comprising inspecting and processing the closed cavity in the model after obtaining the dual-layer cartridge structure model.

Description

Additive manufacturing double-layer cylinder structure and modeling method thereof Technical Field The invention relates to the technical field of additive manufacturing, in particular to a double-layer cylinder structure for additive manufacturing and a modeling method thereof. Background Additive manufacturing technology is based on stacking materials layer by a digital model, and provides revolutionary means for manufacturing complex lightweight structures. The double-layer tube is taken as a typical engineering component, and the innovative design of the sandwich structure is the core for improving the overall performance. At present, the lightweight design of the structure mainly depends on topological optimization. A common approach is to perform a monolithic topological optimization of the entire sandwich region, or to introduce some of the manufacturing constraints in the optimization. However, these existing methods have significant drawbacks. Firstly, the integral optimization involves massive design variables, is high in calculation cost and long in time consumption, and is difficult to meet the actual requirements of engineering on design efficiency. Second, even if process constraints are considered, optimizing the resulting structure tends to be morphologically complex and irregular, lacking in geometric periodicity and regularity. The irregular structure may not only cause unpredictable local stress concentration, but also obviously increase the difficulty of thermal deformation control in the additive manufacturing process and the difficulty of cleaning residual powder after forming, and finally influence the forming quality and manufacturing reliability of the part. Disclosure of Invention In view of the above analysis, the present invention aims to provide an additive manufacturing dual-layer cylinder structure and a modeling method thereof, which are used for at least solving one of the problems that in the prior art, the design efficiency is low due to the adoption of integral topology optimization, and the structure lightweight performance, the feasibility of the additive manufacturing process and the integral regularity are difficult to be ensured synchronously. On one hand, the embodiment of the invention provides an additive manufacturing double-layer cylinder structure, which comprises an inner sleeve, an outer sleeve and a sandwich structure, wherein the inner sleeve and the outer sleeve are coaxially arranged, the sandwich structure is formed by a plurality of topological optimization units which are periodically arrayed in the circumferential direction and the axial direction, each topological optimization unit is a fan-shaped block body and comprises an inner connecting wall connected with the outer wall of the inner sleeve, an outer connecting wall connected with the inner wall of the outer sleeve and a filling structure connected between the inner connecting wall and the outer connecting wall. Furthermore, the filling structure is an integrated supporting framework, and the included angles between the outer surface of the supporting framework and the vertical direction of additive manufacturing are not smaller than a preset minimum self-forming angle theta min. Further, the supporting framework is in an X-shaped cross supporting configuration and comprises a main bearing rib extending along the radial direction of the fan-shaped block body and at least one pair of auxiliary bearing ribs extending from the main bearing rib in a symmetrical and oblique mode, and transition fillets are arranged at the joint of the main bearing rib and the auxiliary bearing rib and the joint of the main bearing rib and the inner connecting wall and the outer connecting wall. Further, the supporting framework is in a tree topology configuration and comprises a main bearing rib extending along the axial direction of the sector block body and a plurality of auxiliary bearing ribs extending symmetrically and obliquely from the main bearing rib and respectively connected to the inner connecting wall and the outer connecting wall. Further, the axial height of the topological optimization unit is d/b, the circumferential outer arc length is 2 pi R/a, and the constraint condition is met, wherein d/b is equal to or greater than 2 pi R/a, d is the axial length of the double-layer cylinder, R is the outer radius of the outer sleeve, a is the number of circumferential arrays, and b is the number of axial arrays. Furthermore, the sandwich structure is internally provided with no completely closed cavity, or a clear powder hole or a clear liquid hole is formed in the existing closed cavity. The invention also provides a parameterized modeling method for generating the additive manufacturing double-layer cylinder structure, which comprises the following steps of: step 1, parameter input and domain division, namely inputting an inner radius R, an outer radius R and an axial length d of the double-layer cylinder s