A viscoelastic damper based on 3D printed auxetic metamaterial

Abstract

The present invention proposes a viscoelastic damper based on 3D printed auxetic metamaterial, comprising an upper steel plate, an intermediate steel plate, a 3D printed auxetic metamaterial, and a lower steel plate. The intermediate steel plate is located between the upper steel plate and the lower steel plate, and there are two 3D printed auxetic metamaterials, which are respectively located between the upper steel plate and the intermediate steel plate, and between the lower steel plate and the intermediate steel plate. Among them, the 3D printed auxetic metamaterial is composed of a plurality of auxetic structural units, which are printed and formed by laser sintering using 3D printed polyurethane powder. And it is vulcanized with the steel plate at a suitable temperature. The 3D printed auxetic metamaterial can adjust the hole size and wall thickness of the lattice unit through the intelligent topology optimization characteristics to adjust the mechanical properties, damping and stiffness of the damper.

Description

Technical Field

[0001] The present invention belongs to the field of structural control and additive manufacturing technology, and specifically relates to a viscoelastic damper based on 3D printed traction metamaterial. Background Art

[0002] Viscoelastic dampers are widely used in earthquake (vibration) resistance of high-rise buildings because they have good shock absorption effect under large and small deformations. They are mainly composed of steel plates and viscoelastic materials, and viscoelastic materials are the core of vibration control. Existing studies have shown that the damage site of frame structures under earthquakes is mainly located at the beam-column nodes. In response to this problem, some experts and scholars have proposed a node viscoelastic damper. Installing this damper at the node can better protect the node and reduce the occupied building space. However, the viscoelastic damper itself has a certain stiffness. The viscoelastic damper installed at the node will increase the node stiffness of the frame structure to a certain extent. Although it has a good limiting effect on the inter-story displacement caused by earthquakes, the control effect on the acceleration of the frame structure is unclear, and it may even increase the acceleration of the structure, affecting the safe use of the building.

[0003] According to the literature, the vibration control effect of some node-type viscoelastic dampers on structures is only reflected in interlayer displacement and interlayer shear force, and the suppression of structural acceleration has not been mentioned. There are problems such as unclear control effect or poor suppression effect. The reason may be related to the high stiffness of the damping material used in the damper. The material used in the above dampers is usually ordinary rubber material. Ordinary rubber materials have problems such as insufficient mechanical properties and uncontrollable shock absorption effect.

[0004] 3D printed auxetic metamaterials have mechanical properties that ordinary rubber does not have, such as high energy absorption efficiency and controllable mechanical behavior. Applying auxetic metamaterials to the design of node dampers can not only greatly improve the shock absorption performance of the node, but also solve the technical problems of traditional rubber dampers such as large deformation capacity, low natural frequency, and long service life, which is of great significance. Therefore, a viscoelastic damper based on 3D printed auxetic metamaterials is developed to realize the production of complex structural damping devices more quickly and intelligently, and it is easy to adjust the damper parameters, and then apply it to the field of vibration control. Summary of the invention

[0005] In response to the technical problems mentioned in the background technology, the present invention provides a viscoelastic damper based on 3D printed auxetic metamaterial.

[0006] In order to achieve the above purpose, the following technical solutions are provided:

[0007] A viscoelastic damper based on a 3D printed auxetic metamaterial, characterized in that it comprises an upper steel plate (1), an intermediate steel plate (2), a 3D printed auxetic metamaterial (3), and a lower steel plate (4); the intermediate steel plate (2) is located between the upper steel plate (1) and the lower steel plate (4); the 3D printed auxetic metamaterial (3) has two pieces, one piece is located between the upper steel plate (1) and the intermediate steel plate (2), and the other piece is located between the lower steel plate (4) and the intermediate steel plate (2); the angle between the long side of the intermediate steel plate (2) and the long sides of the upper steel plate (1) and the lower steel plate (4) is a right angle.

[0008] Furthermore, the 3D printed auxetic metamaterial (3) is composed of a plurality of auxetic structural units (5).

[0009] Furthermore, the tensile structural unit (5) is manufactured by 3D printing, and the units are printed layer by layer to form a viscoelastic material layer.

[0010] Furthermore, the 3D printed auxetic metamaterial (3) is a 3D printed polyurethane material, which is printed layer by layer by laser sintering.

[0011] Beneficial effects:

[0012] The present invention provides a viscoelastic damper based on 3D printed traction metamaterial, which is a type of node damper and has the advantages of small space occupation and good protection of building nodes. At the same time, the energy-consuming material of the present invention is a 3D printed product, which can realize the diversification, rapidity and precision of the production of energy-consuming materials. Traditional rubber production is subtractive manufacturing, which requires traditional tools, fixtures and rollers, which easily causes great waste of raw materials and rubber products. The 3D printed traction metamaterial proposed in the present invention is quickly and accurately manufactured on a single device through three-dimensional CAD data processing and layer-by-layer accumulation. It can well control costs and reduce unnecessary waste.

[0013] Furthermore, the traction structure has good energy absorption. Ordinary rubber node-type viscoelastic dampers will increase the stiffness of the building nodes, resulting in unclear shock absorption control effects on the frame structure under earthquakes, and may even amplify acceleration. Due to the presence of pores, the viscoelastic material layer of the traction structure unit can be adjusted according to actual working conditions compared to the viscoelastic damper based on traditional rubber. At the same time, based on the intelligent characteristics of 3D printing, by adjusting the opening size and wall thickness of the traction lattice unit designed in the software, and then performing topological optimization on it, the dynamic characteristics of the 3D printed product can change with the designed style, thereby obtaining the required target values ​​of dynamic parameters such as stiffness and damping of the viscoelastic damper. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1It is a structural schematic diagram of the present invention;

[0015] Figure 2 A material layer diagram of a 3D auxetic metamaterial of the present invention;

[0016] Figure 3 A three-dimensional view of a auxetic lattice unit cell of the present invention;

[0017] Figure 4 A front view and a plan view of a auxetic lattice unit cell of the present invention;

[0018] Figure 5 It is a split diagram of the auxetic lattice structure unit of the present invention;

[0019] In the figure, there are: 1-upper steel plate; 2-middle steel plate; 3-3D printed auxetic metamaterial; 4-lower steel plate; 5-auxetic lattice unit. DETAILED DESCRIPTION

[0020] The present invention will be described in more detail below in conjunction with the schematic diagram, wherein the preferred embodiment of the present invention is shown, and it should be understood that those skilled in the art can modify the present invention described herein, and still achieve the beneficial effects of the present invention. Therefore, the following description should be understood as being widely known to those skilled in the art, and not as a limitation of the present invention.

[0021] Implementation example Figures 1 to 5 As shown, the present invention provides a viscoelastic damper based on 3D printed traction metamaterial, comprising an upper steel plate, a middle steel plate, a 3D printed traction metamaterial, and a lower steel plate.

[0022] The middle steel plate is located between the upper steel plate and the lower steel plate. There are two 3D printed traction metamaterials, one is located between the upper steel plate and the middle steel plate, and the other is located between the lower steel plate and the middle steel plate. The long side of the middle steel plate is at a right angle to the long sides of the upper steel plate and the lower steel plate.

[0023] The 3D printed auxetic metamaterial is composed of a plurality of auxetic structural units. The auxetic structural units are made by 3D printing, and the units are integrally printed to form an energy-consuming material layer. The 3D printed auxetic metamaterial is a 3D printed polyurethane powder, which is printed layer by layer and formed by laser sintering.

[0024] In this embodiment, the auxetic structural unit is a box-shaped three-dimensional structure, and each corner of the structure has a certain arc angle. Among them, the area of ​​the lower surface of the unit body (the connection surface with the steel plate) is larger than the upper surface of the opposite unit body (the connection surface with another unit), so as to increase the contact area with the steel plate and thus improve the bonding effect. There is a cylindrical opening in the center of each surface of the structural unit and penetrates the unit body, forming a box-shaped three-dimensional structural unit with a hollow structure.

[0025] The viscoelastic material used is a 3D printed traction metamaterial, whose base material is polyurethane powder. The basic properties are: density is 1.21g / cm 3 ; The density of the molding powder package is 0.5g / cm 3 ; The tensile elongation is greater than 350%; the particle size D50 is 65μm; the tensile strength and Shore hardness are 20MPa and 85~90A respectively; the material melting point is 160~170℃.

[0026] The viscoelastic damper proposed in the present invention is a node-type damper, which is installed at the beam-column node of the frame structure. The relative deformation of the beams and columns at the nodes under the action of earthquake or wind vibration causes the steel plate of the damping device to rotate and displace, thereby driving the 3D printed tensile metamaterial of the viscoelastic damper to shear deformation, thereby exerting the damping energy dissipation characteristics of the damper, absorbing and dissipating the energy transmitted to the building structure, thereby protecting the frame structure.

[0027] What is shown in the accompanying drawings of the present invention is only one of the embodiments of the present invention. The actual 3D printed shock-absorbing structure is not limited to that shown in the drawings, the number of layers of the 3D printed tensile metamaterial is not limited to two layers, and the type of viscoelastic damping material is not limited to thermoplastic powdered polyurethane material. Other similar types of viscoelastic damping devices also fall within the protection scope of the present invention.

Claims

1. A viscoelastic damper based on 3D printed auxetic metamaterials, Features: The invention comprises an upper steel plate (1), a middle steel plate (2), a 3D printed traction metamaterial (3), and a lower steel plate (4); the middle steel plate (2) is located between the upper steel plate (1) and the lower steel plate (4); the 3D printed traction metamaterial (3) has two pieces, one piece is located between the upper steel plate (1) and the middle steel plate (2), and the other piece is located between the lower steel plate (4) and the middle steel plate (2); the angle between the long side of the middle steel plate (2) and the long sides of the upper steel plate (1) and the lower steel plate (4) is a right angle; The 3D printed auxetic metamaterial (3) is composed of a plurality of auxetic structural units (5); The traction structural unit (5) is a box-shaped three-dimensional structure, and each corner of the structure has a certain arc angle, wherein the area of ​​the connection surface between the traction structural unit (5) and the steel plate is larger than the area of ​​the connection surface between the traction structural units (5), so as to increase the contact area with the steel plate and thus improve the bonding effect. There is a cylindrical opening at the center of each surface of the traction structural unit (5) and penetrates the unit body, forming a box-shaped three-dimensional structural unit with a hollow structure.

2. A viscoelastic damper based on 3D printing auxetic metamaterial according to claim 1, Features: The traction structural unit (5) is manufactured by 3D printing, and the units are printed as a whole to form a viscoelastic material layer.

3. A viscoelastic damper based on 3D printed auxetic metamaterial according to claim 1, Features: The 3D printed auxetic metamaterial (3) is a 3D printed polyurethane material, which is printed layer by layer by laser sintering.

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