A shrink-connected rod-like hybrid dot lattice structure and a simply supported beam structure thereof

Abstract

This invention discloses a shrinking-connected rod-shaped hybrid lattice structure and its simply supported beam structure, comprising multiple lattice unit cells arranged in a periodic array in three-dimensional space and shrinking-connected structures connecting lattice unit cells of different types of structures. The shrinking-connected structure is a transitional structure adopted for compression projection when connecting two different types of lattice structures. This invention introduces spatial projection into the formation of the connection structure, thereby ensuring the invariance of boundary connections for lattice structures of arbitrary spatial shapes. This facilitates the design of shrinking-connected structures, allowing even inexperienced designers to complete the design of hybrid structures. The lattice hybrid structure exhibits good mechanical properties when applied to simply supported beams and is easy to process and manufacture.

Description

Technical Field

[0001] This invention relates to the field of material structure research, and in particular to the field of topology optimization of rod-shaped lattice structures. The simply supported beam structure has the characteristics of being lightweight, having high load-bearing capacity, and being easy to process. The connection between different types of lattice structures is effective and reliable, so that each lattice unit cell structure can give full play to its performance. Background Technology

[0002] Lattice structures, as lightweight components, promote performance improvement, provide new means for vibration and noise reduction, and advance medical advancements as bone implants. Traditional single-topological lattice structures have significant limitations. To fully utilize the design space offered by additive manufacturing, it is necessary to overcome the limitations of single-morphological structures. Heterogeneous structures achieved through the hybridization of different structures, made from a single material, offer a wider range of substrate choices, enabling broader performance designs and enhancements. Rod-based lattice structures are difficult to express mathematically, and connections between heterogeneous structures are challenging. Therefore, many current hybrid structures can only be chosen from configurations with similar nodal features that facilitate connection. Hybridizing OCT and BCC structures, both having connection points at the eight vertices of a cube (as described in the paper "3D printing of dual phase-strengthened microlattices for lightweight micro aerial vehicles"), can yield high-performance supports for micro-drones. Such hybridization typically requires connections within a complete unit cell; otherwise, disconnections are likely to occur. Researchers have proposed methods such as diameter interpolation, geometric interpolation, and merging adjacent unit cells into transitional unit cells to achieve heterogeneous interface connections (e.g., in the paper "Optimal and continuous multilattice embedding"). However, these methods are highly structure-dependent and require considerable experience to implement. Currently, finding effective connections at arbitrary spatial interfaces for all rod-shaped lattice structures remains a challenge. Summary of the Invention

[0003] The purpose of this invention is to innovatively propose a shrinkage connection structure suitable for rod-shaped hybrid lattice, which makes full use of the spatial projection at the connection of two different lattice structures to achieve a transition connection through unit cell compression. This invention provides a hybrid lattice structure that is easy to design and has good processing performance, as well as a simply supported beam structure that can be filled with different rod-shaped lattice structures according to the load-bearing requirements.

[0004] The present invention discloses a shrinking connection rod-shaped hybrid lattice structure comprising multiple lattice unit cells periodically arrayed in three-dimensional space and shrinking connection structures connecting lattice unit cells of different types; the lattice unit cells include FCC lattice unit cells, BCC lattice unit cells, Cubic lattice unit cells, and OCT lattice unit cells, whose eight vertices respectively exhibit face-centered cubic, body-centered cubic, cubic face-centered, and regular octahedral distributions; the shrinking connection structure is formed by spatially projecting the two lattice structures to be connected onto the connection interface, compressing the two unit cells along the projection direction, and then connecting them together.

[0005] Furthermore, two lattice unit cells with different rod diameters are connected by a transition unit cell designed with a gradient rod diameter.

[0006] Furthermore, the contraction connection structure is formed by compressing the original cubic spatial topology to the spatial projection topology formed by the connection interface and the original boundary, and then connecting the two compressed structures to form a hybrid transition unit cell.

[0007] Furthermore, when there is no overlap between the two lattice structures at the connection point, a supplementary three-dimensional structure is added to the lattice unit cell that was originally not connected at the connection interface, thereby creating a connected interface and realizing the heterogeneous connection of the lattice structures.

[0008] Furthermore, the lattice unit cell is made from photosensitive resin C6202 and fabricated using photopolymerization 3D printing technology.

[0009] Furthermore, the photopolymerization laser power is 900mW, the layer thickness is 0.1mm, the support scanning speed is 5000mm / s, the contour scanning speed is 4000mm / s, and the scanning line spacing is 0.08mm.

[0010] The present invention also discloses a shrink-connected rod-shaped hybrid lattice simply supported beam structure. The simply supported beam structure is divided into different regions with different relative densities according to the stress distribution of the structure. Each region is filled with different types of lattice unit cells, and the shrink-connected structure is used to connect the different types of lattice unit cells.

[0011] Furthermore, the simply supported beam structure is divided into a vertically symmetrical triangular region and a horizontally symmetrical wing-shaped region; the triangular region is filled with a Cubic lattice structure; the upper part of the wing-shaped region is filled with a hybrid lattice structure I formed by an FCC lattice structure, a BCC lattice structure, and a contraction connection structure connecting the two; the middle part of the wing-shaped region is filled with a hybrid lattice structure II formed by a BCC lattice structure with different rod diameters and a transition lattice structure; the four corners of the wing-shaped region are filled with a hybrid lattice structure III formed by an FCC lattice structure, an OCT lattice structure, and a contraction connection structure connecting the two.

[0012] The beneficial effects of this invention are:

[0013] 1. The shrinkage connection structure in this invention is simple in structure. By reasonably adjusting the parameters of the connection structure, the failure of the structure can be controlled to prevent it from occurring at the connection point, thus giving full play to the effect of the hybrid structure.

[0014] 2. The simply supported beam structure of the present invention is lightweight and has good mechanical properties. By filling the lattice structure according to the actual load conditions, it can meet more working conditions.

[0015] 3. The connection strategy adopted in this invention has wide applicability in rod-based hybrid structures, which can help the hybrid structure maximize its advantages and enrich the design of personalized hybrid structures. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] Figure 1 Schematic diagram of a simply supported beam structure with a rod-shaped hybrid lattice for shrinkage connection;

[0018] Figure 2 (a) is a schematic diagram of the FCC lattice unit cell structure in the prior art;

[0019] Figure 2 (b) is a schematic diagram of the BCC lattice unit cell structure in the prior art;

[0020] Figure 2 (c) is a schematic diagram of the Cubic lattice unit cell structure in the prior art;

[0021] Figure 2 (d) is a schematic diagram of the OCT lattice unit cell structure in the prior art;

[0022] Figure 3 This is a schematic diagram of the shrinkage connection structure when the diameter of adjacent lattice structures changes abruptly in this invention;

[0023] Figure 4 This is a schematic diagram of the shrinking connection structure when adjacent lattice structures are disconnected but their projections intersect in this invention;

[0024] Figure 5 This is a schematic diagram of the shrinkage connection structure when adjacent lattice structures are disconnected in this invention;

[0025] Figure 6 This is a schematic diagram of the bending test results of the simply supported beam structure with shrinkage connection in the rod-shaped hybrid lattice in this invention; Detailed Implementation

[0026] Example 1: Shrink-connected rod-shaped hybrid lattice structure

[0027] The shrinking connection rod-shaped hybrid lattice structure of this embodiment includes multiple lattice unit cells arranged in a periodic array in three-dimensional space and shrinking connection structures connecting lattice unit cells of different types of structures. The lattice unit cells include FCC lattice unit cells, BCC lattice unit cells, Cubic lattice unit cells, and OCT lattice unit cells, whose eight vertices respectively present a face-centered cubic distribution, a body-centered cubic distribution, a cubic face-centered distribution, and a regular octahedral distribution. The shrinking connection structure is formed by spatially projecting the two lattice structures to be connected onto the connection interface, compressing the two unit cells along the projection direction, and then connecting them to each other. The connection interface is a shared interface between adjacent lattice structures, that is, a plane centered between the two lattice unit cells to be connected.

[0028] To demonstrate the invention's generality, body-centered cubic (BCC), face-centered cubic (FCC), cubic face-centered (Cubic), and octahedral (OCT) lattices, all widely representative, were selected, with a unit cell size of 5×5×5 mm³ and a rod diameter of 2 mm. Figure 2 (a) to (d) respectively show the existing FCC, BCC, Cubic and OCT lattice unit cell structures.

[0029] The shrink-fit connection structure of the present invention can be used in any type of hybrid porous structure, which can be divided into three cases. First, as... Figure 3 When two adjacent BCC lattice structures 2-2 and 2-3 with different rod diameters are connected, the transition unit cell is composed of round rods with a gradient change in rod diameter from BCC lattice structure 2-2 to BCC lattice structure 2-3. The rod diameter of this transition unit cell gradually decreases from the connection end with BCC lattice structure 2-2 to the connection end with BCC lattice structure 2-3, thus forming transition unit cell 3-1 for a smooth transition. Secondly, as shown... Figure 4 When the adjacent FCC lattice structure 2-1 and BCC lattice structure 2-2 are disconnected but overlap at their connection point, the lattice structure is compressed from its original cubic spatial topology to a spatial projection topology formed by the connection interface and the original boundary by changing the position of the nodes in the unit cells of FCC lattice structure 2-1 and BCC lattice structure 2-2. Then, the two compressed structures are connected to form a transition unit cell. Since the unit cell structure is complete, the connection characteristics of the boundary are maintained. If the rod diameters of adjacent structures are not equal, a gradient rod diameter variation design is used to connect the adjacent structures. Finally, the compressed hybrid transition unit cell forms a contracted connection structure 4-1 to complete the connection. Finally, as... Figure 5When the adjacent Cubic lattice structure 2-4 and OCT lattice structure 2-5 are completely disconnected, and there is no overlap between the two lattice structures at the connection point, the transition unit cell is composed of the Cubic lattice structure 2-4 and the OCT lattice structure 2-5 after being compressed to half size. Since there is no overlap between the Cubic lattice structure 2-4 and the OCT lattice structure 2-5 at the connection point, a cross-shaped rod with the same diameter as the OCT lattice structure 2-5 is added to the Cubic lattice structure 2-4, which originally had no connection, at the connection interface. The cross-shaped rod is then used to connect the Cubic lattice structure 2-4 to the OCT lattice structure 2-5, forming a shrinkage connection structure 5-1, thereby realizing the heterogeneous connection of the lattice structures.

[0030] Therefore, the shrinking connection rod-shaped hybrid lattice structure of this embodiment projects spatially onto the connection interface formed by two different types of lattice structures. By adjusting the rod diameter, the performance of the connection part can be fine-tuned, making it suitable for effective connection of lattice structures of different shapes with arbitrary cross-sections. This shrinking connection structure has wide adaptability in rod-based hybrid structures and is easy to prepare and process, enriching the personalized design of hybrid lattice structures. The sample was processed using photosensitive resin C6202 for photocuring, with a laser power of 900mW, a layer thickness of 0.1mm, a support scanning speed of 5000mm / s, a contour scanning speed of 4000mm / s, and a scanning line spacing of 0.08mm.

[0031] Example 2: Shrink-connected rod-shaped hybrid lattice simply supported beam structure

[0032] The shrink-connected rod-shaped hybrid lattice simply supported beam structure of this embodiment is divided into different regions with different relative densities according to the stress distribution of the structure. Each region is filled with different types of lattice unit cells, and the shrink-connected structure is used to connect the different types of lattice unit cells.

[0033] like Figure 1As shown, the simply supported beam structure is divided into a vertically symmetrical triangular region and a horizontally symmetrical wing-shaped region. The triangular region bears the highest stress and is filled with a Cubic lattice structure. The wing-shaped region has a moderate stress distribution and is filled with a hybrid lattice structure I, consisting of an FCC lattice structure, a BCC lattice structure, and a contraction connection structure connecting the two. The middle of the wing-shaped region is filled with a hybrid lattice structure II, consisting of BCC lattice structures of different diameters and a transition lattice structure. The four corners of the wing-shaped region bear the lowest stress, ensuring the simply supported beam structure is as lightweight as possible. These corners are filled with a hybrid lattice structure III, consisting of an FCC lattice structure, an OCT lattice structure, and a contraction connection structure connecting the two. Contraction connections are used to connect different structures, resulting in a simply supported beam structure filled with a hybrid lattice. For experimental convenience, shims 2 are added at the supports, and solid structures 1 are added at the stress application points to prevent indentation. A bending test is conducted at a loading speed of 5 mm / min to observe the response of the connection method in its application.

[0034] Experimental results are as follows Figure 6 As shown, the stiffness of the simply supported beam filled with the hybrid lattice structure is 809.5±2.8 N / mm, which is 5.8 times and 1.9 times that of the single BCC and single Cubic structures, respectively. The ultimate load is 3260.4±36.5 N, which is 3.6 times and 1.9 times, respectively. These data all demonstrate the excellent performance of the hybrid structure and allow it to fully leverage its advantages.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A shrink-connected rod-like hybrid dot lattice structure, characterized by: It includes multiple lattice unit cells arranged in a periodic array in three-dimensional space and contraction connection structures connecting lattice unit cells of different types; the lattice unit cells include FCC lattice unit cells, BCC lattice unit cells, Cubic lattice unit cells and OCT lattice unit cells with eight vertices respectively exhibiting face-centered cubic distribution, body-centered cubic distribution, cubic face-centered distribution and regular octahedral distribution. The shrinkage connection structure is formed by spatially projecting the two lattice structures to be connected onto the connection interface, compressing the two unit cells along the projection direction, and then connecting them together. The contraction connection structure is formed by compressing the original cubic spatial topology to the spatial projection topology formed by the connection interface and the original boundary, and then connecting the two compressed structures to form a hybrid transition unit cell. When forming the contraction connection structure through spatial projection, the principle of minimum short distance is taken into account at its projection interface. The symmetry of the original spatial projection is considered to supplement the connection part. A supplementary three-dimensional structure is added to the transition unit cell obtained on the spatial projection plane. The interface that does not have connectivity is stitched together to create a connectivity interface, thereby realizing the heterogeneous connection of the lattice structure.

2. The shrink-connected rod-like hybrid dot lattice structure of claim 1, wherein: Two lattice unit cells with different rod diameters are connected by a transition unit cell designed with gradient rod diameters.

3. The shrink-connected rod-like hybrid dot lattice structure of claim 1, wherein: The lattice unit cells are made from photosensitive resin C6202 and fabricated using photopolymerization 3D printing technology.

4. The shrink-connected rod-like hybrid dot lattice structure of claim 3, wherein: The photopolymerization laser has a power of 900mW, a layer thickness of 0.1mm, a support scanning speed of 5000 mm / s, a contour scanning speed of 4000 mm / s, and a scanning line spacing of 0.08mm.

5. A simply supported beam structure employing the shrink-connected rod-like hybrid dot lattice structure according to any one of claims 1 to 4, characterized by: The simply supported beam structure is divided into different regions with different relative densities according to the stress distribution of the structure. Each region is filled with different types of lattice unit cells, and the different types of lattice unit cells are connected by the shrinkage connection structure. The simply supported beam structure is divided into a vertically symmetrical triangular region and a horizontally symmetrical wing-shaped region. The triangular region is filled with a Cubic lattice structure; the area above the wing-shaped region is filled with a hybrid lattice structure I formed by an FCC lattice structure, a BCC lattice structure, and a contraction connection structure connecting the two. The central part of the wing-shaped area is filled with a hybrid lattice structure II, which is formed by BCC lattice structures with different rod diameters and transition lattice structures; The four corners of the wing-shaped area are filled with a hybrid lattice structure III, which consists of an FCC lattice structure, an OCT lattice structure, and a shrinking connection structure connecting the two.

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