CN-122026114-A - Two-dimensional concave configuration zero thermal expansion metamaterial cell structure, array structure and method

CN122026114ACN 122026114 ACN122026114 ACN 122026114ACN-122026114-A

Abstract

The invention discloses a two-dimensional indent-configuration zero thermal expansion metamaterial cell structure, an array structure and a method, wherein the cell structure comprises m matrix straight parts and m bent double-layer metal beams which are sequentially and alternately connected end to form a closed two-dimensional indent configuration; the double-layer metal beam comprises a bending outer side layer and a bending inner side layer, wherein the thermal expansion coefficient of the bending outer side layer is larger than that of the bending inner side layer, and the cell structure shows zero thermal expansion characteristic in the vertical direction and/or the horizontal direction. When the cell structure is used as a basic module for repeated arrangement and combination, the cell structure can be naturally spliced into a seamless plane or curved surface to form a complete closed bearing structure without additional skin. Provides a novel metamaterial core layer or a main structure solution with high performance and easy integration for the fields of aerospace, precise instruments and the like.

Inventors

ZHANG XIAO
WEI ZHIBO
CAI YAWEN
WANG XIAOYONG
WU JUN

Assignees

天津大学

Dates

Publication Date: 20260512
Application Date: 20251229

Claims (8)

1. The zero thermal expansion metamaterial cell structure with the two-dimensional concave structure is characterized by comprising m matrix straight line parts and m bent double-layer metal beams which are sequentially and alternately connected end to form a closed two-dimensional concave structure, wherein m is a positive integer; The double-layer metal beam comprises a bending outer side layer and a bending inner side layer, and the thermal expansion coefficient of the bending outer side layer is larger than that of the bending inner side layer; When the ambient temperature changes, the double-layer metal beam generates inward or outward bending thermal deformation to drive the cell structure to shrink or expand so as to counteract the thermal expansion or shrinkage of the matrix straight line part material, so that the cell structure presents zero thermal expansion characteristic in the vertical direction and/or the horizontal direction.
2. The two-dimensional indent-configured zero thermal expansion metamaterial cell structure according to claim 1, wherein the material of the curved outer layer is manganese-nickel-copper alloy, the material of the curved inner layer is invar alloy, the components of the manganese-nickel-copper alloy are Mn 75 Ni 15 Cu 10 , the thermal expansion coefficient is 41×10 -6 K -1 , the invar alloy is Ni 36 , and the thermal expansion coefficient is 1.2×10 - 6 K -1 .
3. The two-dimensional concave configuration zero thermal expansion metamaterial cell structure according to claim 1, wherein the cell structure has 12 matrix straight portions and 12 curved double-layer metal beams, and comprises: A first base straight line portion (A1) and a seventh base straight line portion (A7) that are opposed and parallel in the vertical direction; A tenth base straight line portion (a 10) and a fourth base straight line portion (A4) which are opposed and parallel in the vertical direction; And four connection assemblies connected between the first matrix straight line portion, the seventh matrix straight line portion, the tenth matrix straight line portion and the fourth matrix straight line portion, each connection assembly including two matrix straight line portions and three double-layer metal beams; The double-layer metal Liang Bu is arranged at the corner joint between the straight parts of each matrix.
4. A two-dimensional concave configuration zero thermal expansion array structure, characterized in that the array structure is formed by connecting a plurality of cell structures as defined in any one of claims 1 to 3 as basic building units in a manner of sharing boundaries.
5. The two-dimensional concave configuration zero thermal expansion array structure according to claim 4, wherein the array structure is arranged in any of the following ways: The single-column linear arrangement is characterized in that a plurality of cell structures are sequentially arranged along the vertical direction or the horizontal direction, and the linear parts of the adjacent cell structures relative to the matrix are aligned and connected; a plurality of cell structures are arranged in a two-dimensional plane manner, a plurality of cell structures are arrayed in the vertical direction and the horizontal direction to form a plane structure, and the bending directions of the double-layer metal beams of the cell structures are kept consistent; The cell structures are arranged in an annular mode, the cell structures in single-column linear arrangement are bent, folded and connected end to end, and the cell structures are connected through angle connectors to form an annular structure; The annular structures are arranged in a spherical mode, and the two annular structures which are perpendicular to each other are overlapped and combined; and the annular structures are arranged in a cylindrical shape and are correspondingly connected up and down along the axial direction.
6. The two-dimensional concave configuration zero thermal expansion array structure according to claim 4, wherein the bending direction of the double-layer metal beams of each cell structure is kept consistent when the cell structures are arranged in an array, so as to ensure that the zero thermal expansion performance of the whole structure is consistent.
7. A method of designing a zero thermal expansion structure based on the cell structure of any one of claims 1-3, comprising: constructing a two-dimensional concave configuration model, and determining motion constraint conditions of the model in the vertical and horizontal directions; Arranging double-layer metal beams at corners of the two-dimensional concave configuration, and selecting a material with a high thermal expansion coefficient as a bending outer layer and a material with a low thermal expansion coefficient as a bending inner layer; According to the difference of thermal expansion coefficients of the material of the bending outer side layer and the material of the bending inner side layer, the arc length of the double-layer metal beam is designed to enable the bending deformation degree to be matched with the movement angle of the two-dimensional concave configuration, and thermal deformation coordination of each part is realized, so that the macroscopic zero thermal expansion characteristic is obtained; the cell structures are combined according to a predetermined arrangement mode to form a zero thermal expansion structure.
8. A method of manufacturing a cell structure according to any one of claims 1-3, comprising: Nickel alloy with high thermal expansion coefficient is used as a bending outer layer material of the double-layer metal beam, invar alloy with low thermal expansion coefficient is used as a bending inner layer material of the double-layer metal beam; The two materials are combined through lamination, welding or bonding processes and are connected with the straight line part of the matrix, so that the zero thermal expansion cell structure with a closed two-dimensional concave configuration is formed.

Description

Two-dimensional concave configuration zero thermal expansion metamaterial cell structure, array structure and method Technical Field The invention belongs to the technical field of zero-thermal-expansion metamaterial configurations, and particularly relates to a two-dimensional concave-configuration zero-thermal-expansion metamaterial cell structure, an array structure and a method. Background In the fields of precision instruments, aerospace and the like, the thermal stability of a structure is important. In the prior art, the way of realizing zero thermal expansion or near zero thermal expansion mainly has the bottleneck that firstly, based on the scheme of a single compound (such as invar alloy) or a traditional composite material (such as fiber/particle reinforced composite material), the problems of narrow applicable temperature area, high material density, obvious anisotropism and the like exist, and the problem of poor long-term reliability due to mismatch of thermal expansion of a reinforcing phase and a matrix is easy to generate interface cracking and delamination failure in a temperature alternating environment. Secondly, although a new thought is provided based on the scheme of metamaterial microstructure design, the inherent contradiction exists in the configuration, for example, the concave or chiral structure which depends on bending deformation can realize negative thermal expansion, but the structural rigidity and bearing capacity of the structure are generally poor, and the stretching dominant lattice structure with higher rigidity is limited by the limited thermal expansion coefficient difference between the existing metal/polymer component materials, so that the macroscopic negative thermal expansion coefficient regulation range is narrow, and the positive thermal expansion of the matrix material is difficult to precisely match and completely offset to realize extremely low net thermal expansion rate. The existing zero expansion structure is mostly of an open design in the manufacturing and integration layers, a closed bearing space cannot be formed by the existing zero expansion structure, the additional skin is needed, the weight and the process complexity are increased, meanwhile, the zero expansion structure depends on a precise hinge and pre-tightening assembly, the risk of performance drift caused by pre-tightening force relaxation exists, the manufacturing cost is high, and large-scale application is difficult. In addition, the difficulties of interfacial bonding strength, manufacturing defect control, accurate testing of extremely low thermal expansion coefficients, and the like faced by multi-material metamaterials have also prevented the development of engineering practices from theoretical design. Therefore, there is a strong need in the art for a new solution that can achieve a very low thermal expansion in a wide temperature range, high structural rigidity, self-sealing properties, no need for pre-tightening and precision hinges, and easy processing and integration in arrays, so as to overcome the above-mentioned systematic technical bottlenecks. Disclosure of Invention The invention aims to overcome the defects in the prior art, solve the contradiction of the prior zero expansion structure and the defect that a closed bearing space cannot be formed, and provide a two-dimensional indent-configuration zero thermal expansion metamaterial cell structure, an array structure and a method, wherein the cell structure is a two-dimensional indent-configuration zero thermal expansion unit with thermal expansion rates smaller than a certain value in a certain temperature range and in vertical and horizontal directions, so that the cell structure can directly replace the traditional aluminum alloy and titanium alloy honeycomb core materials while keeping the closed cross section and the arraying capability, solve the defects that the prior zero expansion structure contradiction and the closed bearing space cannot be formed, and provide a next-generation metamaterial core layer solution for aerospace, precise instruments and thermal protection systems. The invention aims at realizing the following technical scheme: A two-dimensional indent-configuration zero thermal expansion metamaterial cell structure comprises m matrix straight line parts and m bent double-layer metal beams which are sequentially and alternately connected end to form a closed two-dimensional indent configuration, wherein m is a positive integer; The double-layer metal beam comprises a bending outer side layer and a bending inner side layer, and the thermal expansion coefficient of the bending outer side layer is larger than that of the bending inner side layer; When the ambient temperature changes, the double-layer metal beam generates inward or outward bending thermal deformation to drive the cell structure to shrink or expand so as to counteract the thermal expansion or shrinkage of the matrix straight line part mat