Double-deformation-mode vibration isolation honeycomb cylindrical shell

Abstract

The invention discloses a double-deformation-mode vibration isolation honeycomb cylindrical shell which comprises a hollow cylindrical shell body composed of an inner skin and an outer skin, a honeycomb interlayer is arranged between the inner skin and the outer skin, the honeycomb interlayer comprises a plurality of honeycomb unit cells, the honeycomb unit cells are stretched quadrangular star-shaped honeycomb unit cells, and the honeycomb unit cells are arranged in the hollow cylindrical shell body. A pair of short oblique ligaments are symmetrically arranged on the inner concave corners of the two long edges of each honeycomb unit cell respectively, a pair of long oblique ligaments are symmetrically arranged on the inner concave corners of the two short edges of each honeycomb unit cell respectively, and the honeycomb unit cells are arranged in a bending mode according to the circumferential curvature of the hollow cylindrical shell. Two-stage deformation is achieved through the stretched quadrangular star-shaped structure and the eight oblique ligaments, reverse stretching traction loads are provided, the inward concave trend of a main body supporting honeycomb is hindered, part of vertical loads are borne, and the overall bearing performance is improved; through the stretched quadrangular star-shaped structure and the eight oblique ligaments, the honeycomb structure has customizable circumferential and radial vibration isolation performance.

Description

Technical Field

[0001] The invention relates to the technical field of honeycomb materials, and in particular to a double-deformation mode vibration-isolating honeycomb cylindrical shell. Background Art

[0002] The cylindrical shell structure is the most widely used structural unit in engineering, and the vibration isolation design for the vibration transmission path based on it has great application potential. Thanks to its excellent static mechanics and lightweight properties, the traditional grid structure has been widely used. Since the lightweight and thin-walled components in the grid structure are easily excited by external excitation and vibrate violently, the dynamic mechanical properties of the traditional grid structure are often poor. The introduction of the phononic crystal band theory provides a new solution for the vibration reduction and noise reduction design of periodic grid structures. Based on the traditional grid structure, a series of honeycomb configurations with excellent vibration characteristics have been proposed.

[0003] Negative Poisson's ratio and negative stiffness effects have been widely verified to have excellent potential for vibration isolation applications. Applying the honeycomb configuration of negative Poisson's ratio materials to cylindrical shell structures can greatly increase the performance of cylindrical shell structures. However, negative Poisson's ratio and negative stiffness honeycomb configurations often contain concave, chiral and curved beam structures. These flexible components greatly hinder the overall static stiffness of the honeycomb and are prone to instability when the structure is deformed by force, which greatly affects the honeycomb's bearing performance, thereby limiting actual engineering scenarios, especially its application as a honeycomb cylindrical shell unit component. Summary of the invention

[0004] The embodiment of the present invention provides a dual deformation mode vibration isolation honeycomb cylindrical shell to solve the problem in the prior art that the honeycomb configuration structure is very easy to become unstable when subjected to force deformation, which greatly affects the honeycomb bearing performance and leads to limitations in actual engineering scenarios.

[0005] On the one hand, an embodiment of the present invention provides a dual deformation mode vibration isolation honeycomb cylindrical shell, comprising:

[0006] An inner skin, an outer skin and a honeycomb interlayer, wherein the inner skin and the outer skin form a hollow cylindrical shell, the inner skin is arranged on the inner side of the hollow cylindrical shell, the outer skin is arranged on the outer side of the hollow cylindrical shell, the honeycomb interlayer is arranged between the inner skin and the outer skin, the honeycomb interlayer comprises a plurality of honeycomb cells, the honeycomb cells are stretched four-pointed star-shaped honeycomb cells, a pair of short oblique ligaments are symmetrically arranged on the concave angles of the two long sides of the honeycomb cells, a pair of long oblique ligaments are symmetrically arranged on the concave angles of the two short sides of the honeycomb cells, and the honeycomb cells are bent according to the circumferential curvature of the hollow cylindrical shell.

[0007] In a possible implementation, the length of the honeycomb unit cell is L, the height of the honeycomb unit cell is H, the short oblique ligaments of the honeycomb unit cell are symmetrically arranged on the concave angles of the two long sides at a distance g from the vertical midline of the honeycomb unit cell, and the long oblique ligaments of the honeycomb unit cell are symmetrically arranged on the concave angles of the two short sides at a distance h from the horizontal midline of the honeycomb unit cell.

[0008] In a possible implementation, the end of the short oblique ligament is at a distance e from the vertical midline of the honeycomb unit cell, and the end of the long oblique ligament is at a distance f from the horizontal midline of the honeycomb unit cell.

[0009] In a possible implementation, the distance from the top of the concave angles of the two long sides to the horizontal midline of the honeycomb cell is a, and the distance from the top of the concave angles of the two short sides to the vertical midline of the honeycomb cell is d.

[0010] In a possible implementation, the two oblique sides of the inner concave angles of the two long sides are deformed and bent at a position 1 / 6L away from the vertical center line of the honeycomb unit cell. After deformation and bending, the two oblique sides are horizontally parallel to the horizontal center line of the honeycomb unit cell. The horizontal length of the two oblique sides after deformation and bending is b. The vertical distance between the two oblique sides and the end of the short oblique ligament is c. L = 4H = 6b, and e <g,f<h,d<2b,a<1 / 2H-c。

[0011] A double deformation mode vibration isolation honeycomb cylindrical shell in the present invention has the following advantages:

[0012] (1) The two-level deformation is achieved through the stretched four-pointed star structure and eight oblique ligaments, which provides a reverse tensile traction load, hinders the concave trend of the main supporting honeycomb, bears part of the vertical load, and improves the overall bearing performance.

[0013] (2) The stretched four-pointed star structure and eight oblique ligaments give the honeycomb configuration customizable circumferential and radial vibration isolation performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 A schematic diagram of a honeycomb unit cell structure of a double deformation mode vibration isolation honeycomb cylindrical shell provided in an embodiment of the present invention;

[0016] Figure 2A schematic diagram of a periodic honeycomb cylindrical shell of a double deformation mode vibration isolation honeycomb cylindrical shell provided by an embodiment of the present invention;

[0017] Figure 3 A schematic diagram of honeycomb unit cell curvature modeling of a double deformation mode vibration isolation honeycomb cylindrical shell provided in an embodiment of the present invention;

[0018] Figure 4 A quasi-static compression model diagram of a honeycomb unit cell in double deformation mode of a double deformation mode vibration isolation honeycomb cylindrical shell provided by an embodiment of the present invention;

[0019] Figure 5 A static compression force-displacement curve diagram of a honeycomb unit cell of a double deformation mode vibration isolation honeycomb cylindrical shell provided in an embodiment of the present invention;

[0020] Figure 6 A schematic diagram of a corresponding node deformation mode of a honeycomb structure of a double deformation mode vibration isolation honeycomb cylindrical shell provided by an embodiment of the present invention;

[0021] Figure 7 A schematic diagram of a three-dimensional model of a double deformation mode vibration isolation honeycomb cylindrical shell provided in an embodiment of the present invention;

[0022] Figure 8 A cylindrical shell radial vibration transmissibility curve diagram of a double deformation mode vibration isolation honeycomb cylindrical shell provided in an embodiment of the present invention;

[0023] Fig. 9 A curve diagram of the circumferential vibration transmissibility of a cylindrical shell of a double deformation mode vibration isolation honeycomb cylindrical shell provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Figure 1 A schematic structural diagram of a dual-deformation mode vibration isolation honeycomb cylindrical shell provided in an embodiment of the present invention; an embodiment of the present invention provides a dual-deformation mode vibration isolation honeycomb cylindrical shell, comprising:

[0026] An inner skin 1, an outer skin 2 and a honeycomb interlayer 3, wherein the inner skin 1 and the outer skin 2 form a hollow cylindrical shell, the inner skin 1 is arranged on the inner side of the hollow cylindrical shell, the outer skin 2 is arranged on the outer side of the hollow cylindrical shell, the honeycomb interlayer 3 is arranged between the inner skin 1 and the outer skin 2, the honeycomb interlayer 3 includes a plurality of honeycomb cells 4, the honeycomb cells 4 are stretched four-pointed star-shaped honeycomb cells, a pair of short oblique ligaments 5 are symmetrically arranged on the concave angles of the two long sides of the honeycomb cells 4, a pair of long oblique ligaments 6 are symmetrically arranged on the concave angles of the two short sides of the honeycomb cells 4, the honeycomb cells 4 are bent according to the circumferential curvature of the hollow cylindrical shell, the length of the honeycomb cells 4 is L, the height of the honeycomb cells 4 is H, the short oblique ligaments 5 of the honeycomb cells 4 are symmetrically arranged on the concave angles of the two long sides at a distance g from the vertical midline of the honeycomb cells 4 , the long oblique ligament 6 of the honeycomb unit cell 4 is symmetrically arranged on the concave angles of the two short sides at a distance h from the horizontal midline of the honeycomb unit cell 4, the end of the short oblique ligament 5 is at a distance e from the vertical midline of the honeycomb unit cell 4, the end of the long oblique ligament 6 is at a distance f from the horizontal midline of the honeycomb unit cell 4, the distance from the top of the concave angle of the two long sides to the horizontal midline of the honeycomb unit cell 4 is a, the distance from the top of the concave angle of the two short sides to the vertical midline of the honeycomb unit cell 4 is d, the two hypotenuses of the concave angles of the two long sides are deformed and bent at a position 1 / 6L away from the vertical midline of the honeycomb unit cell 4, the two hypotenuses are horizontally parallel to the horizontal midline of the honeycomb unit cell 4 after deformation and bending, the horizontal part length of the two hypotenuses after deformation and bending is b, the vertical distance between the two hypotenuses and the end of the short oblique ligament 5 after horizontalization is c, L=4H=6b, e <g,f<h,d<2b,a<1 / 2H-c。

[0027] For example, in order to overcome the problem of insufficient static bearing capacity of the current vibration isolation honeycomb configuration, the present invention flattens the upper and lower contact areas of the traditional four-pointed star honeycomb to improve the internal deformation contact properties, and uses two oblique ligaments to replace the conventional single straight ligament connection to improve the deformation stability. According to the phononic crystal band theory, without changing the designed honeycomb topology configuration, the band gap of the target vibration isolation frequency band is obtained through geometric parameter design, so that the vibration isolation frequency band of the invented vibration isolation honeycomb cylindrical shell can be adjusted. The default initial parameters of the honeycomb unit cell 4 are as shown in the following table and Figure 1 As shown:

[0028] Table 1. Initial geometric parameters of honeycomb unit cell 4 in dual deformation mode

[0029] parameter L a c d e f g h <![CDATA[t h ]]> <![CDATA[t c ]]> Value(mm) 120 9 2 27 3.5 5 15 8 1.5 1

[0030] The honeycomb unit cell 4 is bent according to the circumferential curvature of the hollow cylindrical shell. The honeycomb unit cell 4 with the same curvature as the cylindrical shell should be obtained by modeling first, as follows:

[0031] like Figure 2 , 3 As shown in the figure, the geometry of a periodic honeycomb cylindrical shell with n layers of radial unit cells is given, where the longitudinal dimension of the honeycomb corresponds to the radial dimension of the curvature honeycomb, that is, the radial dimension of the structure after bending is consistent with the longitudinal dimension before bending. From this, the radial dimension expression of the periodic honeycomb cylindrical shell can be deduced:

[0032] R ti -R bi =H(i=1,2,...,n),R outer -R innner =nH

[0033] Among them, H is the longitudinal dimension of the honeycomb before bending deformation, i is the number of layers corresponding to the unit cell, and R ti and R bi They correspond to the inner and outer diameters of the outer contour of the single cell after the bending deformation of the i-th layer of honeycomb structure, R inner and R outer The inner diameter and outer diameter of the periodic honeycomb cylindrical shell are respectively. Based on this formula, combined with the longitudinal dimension relationship of each part of the initial structure (see Table 1), the radial dimensions of each part of the curvature structure can be obtained.

[0034] Different from radial dimensions, the circumferential dimensions of the curvature honeycomb are expressed in circular angles. The nodes of the initial structure located on the same vertical line are located on the same circular angle ray after bending deformation. The bottom dimension of the first layer of honeycomb is used as the deformation reference, i.e. L b1 =L, the conversion formula between horizontal dimension and circular angle is as follows:

[0035] θ s =L / R inner

[0036] Among them, θ s is the circumferential angle corresponding to the outer contour of a single honeycomb, and L is the transverse dimension of the honeycomb before bending and deformation. Based on this formula, combined with the transverse dimension relationship of each part of the initial structure, the circumferential dimensions of each part of the curvature structure can be obtained.

[0037] In summary, the spatial coordinates of each node inside the periodic honeycomb cylindrical shell are represented by the corresponding circular angle and radial size of the curvature unit cell.

[0038] The base material parameters of honeycomb unit cell 4 are as follows:

[0039] Density: 2700kg / m3, Young's modulus: 70GPa, Poisson's ratio 0.33.

[0040] In a possible embodiment, the quasi-static compressive mechanical response of the honeycomb configuration in the double deformation mode is simulated using the ABAQUS / EXPLICT display dynamics module. The compression model is shown as follows: Figure 4 As shown, the composition includes a main periodic honeycomb structure and upper and lower plates. Considering the honeycomb size effect, the main periodic honeycomb structure has 5 layers of unit cells in the horizontal direction and 10 layers of unit cells in the vertical direction, and the out-of-plane size is 6mm. The simulation uses aluminum as the matrix material. Since the strain sensitivity of aluminum is very low, the ideal plasticity model is selected for the material aluminum here, which obeys the Mises yield criterion. Its physical properties are: density ρ = 2700kg / m3, Young's modulus E = 68GPa, Poisson's ratio υ = 0.3, and yield stress σy = 255MPa. Define global general contact, set the tangential contact friction coefficient to 0.2, and set the normal contact behavior to hard contact. In the model initialization stage, the upper and lower plates are defined as rigid bodies, such as Figure 4 As shown in the figure, its degrees of freedom are bound to reference points RP-1 and RP-2 respectively, all degrees of freedom of reference point RP-2 are constrained, and only the translational degree of freedom in the y direction is opened at reference point RP-1. In addition, to ensure that the MDM honeycomb only undergoes in-plane deformation, all out-of-plane degrees of freedom of the structure are constrained.

[0041] like Figure 5 As shown, it can be seen intuitively that the designed honeycomb configuration has two obvious deformation stages. There is a linear elastic stage at the beginning of deformation stages I and II, and the corresponding structural stiffnesses are 144.6kN / m and 1215.6kN / m respectively. In addition, the maximum support reaction forces in deformation stages I and II are 0.52kN and 6.78kN respectively. Therefore, the bearing capacity of honeycomb deformation stage II is significantly improved compared with stage I. In order to reveal the transformation mechanism of the proposed honeycomb mechanical response, Figure 6 The honeycomb deformation mode of the corresponding deformation stage is further given. It can be seen that in deformation stage I, the upper and lower main body supporting honeycombs are not in contact. At this time, the upper and lower connecting oblique ligaments of the honeycomb play the main supporting role; in deformation stage II, the upper and lower main body supporting honeycombs are in contact. At this time, the main body supporting honeycombs replace the connecting oblique ligaments to play a supporting role, which is intuitively reflected in the surge of deformation support reaction force. In addition, under the action of the deformation coordination mechanism, the concave angle of the main body supporting honeycomb will shrink inward under the action of the vertical compression load, while the connecting oblique ligaments on both sides provide reverse tensile traction loads, hindering the concave trend of the main body supporting honeycomb, and to a certain extent bearing part of the vertical load, which also has a positive effect on improving the bearing capacity of the structure. In summary, the proposed honeycomb benefits from the change of deformation mode, and the overall bearing performance is greatly improved.

[0042] In a possible embodiment, Figure 7 As shown in the figure, a three-dimensional model of a honeycomb cylindrical shell with double deformation mode is given. The model has 8 honeycomb cells arranged in the circumferential direction. The specific geometry is shown in Table 2.

[0043] Table 2 Geometric parameters of shell samples

[0044] parameter <![CDATA[H0]]> <![CDATA[R outer ]]> <![CDATA[R inner ]]> <![CDATA[t outer ]]> <![CDATA[t inner ]]> <![CDATA[t h ]]> <![CDATA[t c ]]> <![CDATA[t p ]]> <![CDATA[l p ]]> Value(mm) 250.0 228.4 165.9 3.0 2.0 2.0 1.5 2.0 30.0

[0045] Among them, H0 is the axial dimension of the shell sample, R inner and R outer are the inner and outer diameters of the shell sample, respectively, t inner and t outer are the inner skin thickness and outer skin thickness of the shell sample, t h and t c are the honeycomb wall thickness of the sandwich body support and the wall thickness of the connecting oblique ligament of the shell sample, t p and l p The height and bottom length of the square boss of the shell sample vibration monitoring are respectively. The F1, F2, and F3 are the excitation positions of the force application.

[0046] The experimental shell sample was prepared by stereolithography. The base material of the shell sample is photosensitive resin, and its material properties are as follows: density ρ = 1150 kg / m3, Young's modulus E = 2.60 GPa, Poisson's ratio υ = 0.42. Using the exciter as the excitation source, a sweep frequency experiment was carried out to obtain the vibration transmissibility of the prepared shell sample under different frequency excitations. In keeping with the experimental equipment, a numerical simulation model was established to calculate the vibration transmission response of the shell. The experimental and simulation results of the radial and circumferential vibration transmissibility of the shell are shown in Figure 8 , 9 . It can be seen intuitively that the simulation results are highly consistent with the experimental results, both showing that the shell has obvious radial and circumferential vibration isolation frequency bands, verifying the excellent vibration isolation performance of the invented shell. In addition, the circumferential vibration isolation frequency band has a high degree of overlap with the circumferential band gap calculated by the energy band theory, indicating the effectiveness of the vibration reduction honeycomb configuration design. That is, the overall vibration isolation frequency band of the shell can be pre-designed theoretically to ensure that the final shell has the vibration isolation capability required by the corresponding working frequency band.

[0047] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0048] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A double deformation mode vibration isolation honeycomb cylindrical shell, characterized in that: include: An inner skin (1), an outer skin (2) and a honeycomb interlayer (3), wherein the inner skin (1) and the outer skin (2) form a hollow cylindrical shell, wherein the inner skin (1) is arranged on the inner side of the hollow cylindrical shell, and the outer skin (2) is arranged on the outer side of the hollow cylindrical shell, and the honeycomb interlayer (3) is arranged between the inner skin (1) and the outer skin (2), and the honeycomb interlayer (3) comprises a plurality of honeycomb cells (4), wherein the honeycomb cells (4) are stretched four-pointed star-shaped honeycomb cells, and a pair of short oblique ligaments (5) are symmetrically arranged on the inner concave corners of the two long sides of the honeycomb cells (4), and a pair of long oblique ligaments (6) are symmetrically arranged on the inner concave corners of the two short sides of the honeycomb cells (4), and the honeycomb cells (4) are bent according to the circumferential curvature of the hollow cylindrical shell.

2. A double deformation mode vibration isolation honeycomb cylindrical shell according to claim 1, characterized in that: The honeycomb unit cell (4) is L in length and H in height. The short oblique ligaments (5) of the honeycomb unit cell (4) are symmetrically arranged on the concave corners of the two long sides at a distance g from the vertical center line of the honeycomb unit cell (4). The long oblique ligaments (6) of the honeycomb unit cell (4) are symmetrically arranged on the concave corners of the two short sides at a distance h from the horizontal center line of the honeycomb unit cell (4).

3. The double deformation mode vibration isolation honeycomb cylindrical shell according to claim 2, characterized in that: The end of the short oblique ligament (5) is at a distance e from the vertical midline of the honeycomb unit cell (4), and the end of the long oblique ligament (6) is at a distance f from the horizontal midline of the honeycomb unit cell (4).

4. The double deformation mode vibration isolation honeycomb cylindrical shell according to claim 3, characterized in that: The distance from the top of the indented angles of the two long sides to the horizontal midline of the honeycomb unit cell (4) is a, and the distance from the top of the indented angles of the two short sides to the vertical midline of the honeycomb unit cell (4) is d.

5. The double deformation mode vibration isolation honeycomb cylindrical shell according to claim 4, characterized in that: The two oblique sides of the inner concave angles of the two long sides are deformed and bent at a position 1 / 6L away from the vertical center line of the honeycomb unit cell (4). After deformation and bending, the two oblique sides are horizontally parallel to the horizontal center line of the honeycomb unit cell (4). The length of the horizontal part of the two oblique sides after deformation and bending is b. The vertical distance between the two oblique sides and the end of the short oblique ligament (5) after being horizontal is c. L = 4H = 6b, and e <g,f<h,d<2b,a<1 / 2H-c。

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