Bionic supporting structure and optimization design method thereof

Abstract

According to the bionic supporting structure and the optimization design method thereof, an extra inerter is installed in an X-shaped support to achieve coupling of nonlinear rigidity and the damping effect, so that the vibration suppression performance is enhanced, the influence of various parameters of the structure is comprehensively researched, parameter optimization design is conducted in a targeted mode, and the design method is suitable for the design of the bionic supporting structure. The supporting structure has ideal non-linear rigidity, non-linear damping and non-linear mass inertia force, the ultra-low inherent frequency of the structure can be achieved, and the vibration isolation performance is improved.

Description

[Technical field]

[0001] The invention relates to the technical field of shock absorbers, and in particular to a bionic support structure and an optimization design method thereof. [Background technology]

[0002] Among various structural vibrations, ultra-low frequency vibration is an important form of vibration. It may cause resonance of engineering structures, resulting in excessive amplitude and exposing engineering systems to the risk of failure. Effective vibration control methods are essential to improving the safety and stability of structures.

[0003] In the related art, a linear vibration isolation system is set up to perform vibration reduction. In order to enable the structure to obtain a wider vibration isolation frequency range and achieve ultra-low frequency vibration isolation, it is necessary to reduce the natural frequency of the vibration isolation system, which will lead to a reduction in its stiffness and weaken its bearing capacity. Based on this, the related literature has proposed a quasi-zero stiffness (QZS) isolator with nonlinear high static and low dynamic stiffness, so that the structure has low dynamic stiffness while maintaining a high static bearing capacity. However, the QZS characteristics of the quasi-zero stiffness isolator may produce unsafe strong nonlinear phenomena (such as bifurcation, instability, subharmonic and superharmonic resonance) under large excitation. Therefore, it is necessary to provide a bionic support structure with an inertia container to optimize the vibration reduction design method to solve the above problems. [Summary of the invention]

[0004] The technical problem to be solved by the present invention is to provide a bionic support structure and an optimization design method thereof, by installing an additional inertia container inside the X-shaped support to achieve the coupling of nonlinear stiffness and damping effect, thereby enhancing the vibration suppression performance; and by comprehensively studying the influence of various parameters of the structure, targeted parameter optimization design is carried out, so that the support structure has ideal nonlinear stiffness, nonlinear damping and nonlinear mass inertia, which can achieve ultra-low natural frequency of the structure and improve vibration isolation performance.

[0005] To achieve the above object, the technical solution of the present invention is:

[0006] A bionic support structure comprises a base plate, an X-shaped support assembly, a connecting rod, a mass block, a first connecting member and a second connecting member, wherein the X-shaped support assembly comprises at least one X-shaped support unit arranged in a vertical direction, wherein the top of each X-shaped support unit is provided with two first connecting points, and the bottom of each X-shaped support unit is provided with two second connecting points; the number of the connecting rods is four, and the lengths of the four connecting rods are equal, and the four connecting rods are divided into two upper connecting rods and two lower connecting rods, wherein the tops of the two upper connecting rods are hinged to the same hinge point on the mass block, and the bottoms are respectively hinged to the two first connecting points at the top of the X-shaped support assembly; the bottoms of the two lower connecting rods are hinged to the same hinge point on the base plate, and the tops are respectively hinged to the two second connecting points at the bottom of the X-shaped support assembly; in each X-shaped support unit, one of the first connecting member and the second connecting member is connected between the two first connecting points, and the other of the first connecting member and the second connecting member is connected between the two second connecting points, wherein the first connecting member is an inertia container, and the second connecting member comprises a horizontal spring and a damper arranged in parallel.

[0007] Preferably, the X-shaped supporting unit comprises two force arms arranged crosswise in an X shape, and the middle of the two force arms are hinged.

[0008] Preferably, the inertia container comprises a shell, a first gear, a second gear, a third gear, a flywheel and a rack; the shell forms a receiving space, and the first gear, the second gear, the third gear and the flywheel are all received in the receiving space; the first gear and the second gear are fixed, the third gear and the flywheel are fixed, the second gear and the third gear are meshed, the rack is meshed with the first gear, and the end of the rack passes through the shell and is exposed to form a first connection point; a second connection point is provided at one end of the shell away from the first connection point, and the inertia container is connected to the first connection member through the first connection point and the second connection point.

[0009] Preferably, the axes of the first gear and the second gear are located on the same straight line, and the axes of the third gear and the flywheel are located on the same straight line.

[0010] The present invention also provides an optimization design method for the above-mentioned bionic support structure, comprising the following steps:

[0011] S1: constructing a dynamic model of the bionic support structure, selecting θ, L, and n as parameters to be optimized, wherein θ represents the initial angle of the connecting rod relative to the horizontal plane, L is the length of the connecting rod, and n is the number of the X-shaped support monomers;

[0012] S2: The three parameters are divided into two static parameters and one dynamic parameter by using the control variable method, a fixed value is assigned to the static parameter, the value of the dynamic parameter is adjusted within the design range, and the stiffness force F of the bionic support structure is output based on the dynamic model. k The displacement y1 of the mass block is k -y1 curve, traverses the entire design range of the dynamic parameters, and obtains F under different values ​​of the dynamic parameters k -y1 curve, select the F with the best forward nonlinear result k -The dynamic parameter value corresponding to the y1 curve is taken as the optimal value, and the classification of static parameters and dynamic parameters is adjusted to obtain the optimal values ​​of the three parameters respectively.

[0013] S3: Construct a displacement transfer model of the bionic support structure, expressed as:

[0014]

[0015] In the formula, |·| represents the norm, A is the amplitude of the bionic support structure, φ is the phase angle, A0 is the basic excitation amplitude, Ω is the dimensionless excitation frequency, τ is dimensionless time, τ=ω1t, ω is the basic excitation frequency, ω1 is the natural frequency of the bionic support structure, ξ n is the equivalent damping ratio of the bionic support structure, c is the damping coefficient of the damper, and f c is the nonlinear damping of Taylor series expansion, M represents the mass of the mass block;

[0016] S4: Use the best value Complete the construction of the dynamic model, adjust the value of c, and calculate the structural displacement transfer rate T of the bionic support structure under different values. d , and the structural displacement transmissibility T is obtained d The curve with the smallest resonance peak and the lowest resonance frequency is selected as the optimal value of c, which is expressed as the optimal value Complete the process of optimizing design.

[0017] Preferably, the kinetic model is expressed as:

[0018]

[0019] In the formula, represents the vertical acceleration of the mass block, represents the vertical velocity of the mass block, represents the base excitation acceleration of the mass block, k represents the stiffness of the horizontal spring, F in1 and F in2represents the inertial force of the bionic support structure, F c is the damping force of the bionic support structure, F k is the stiffness force of the bionic support structure, β is the ratio of the effective mass of the inertia container to the mass of the mass block, and y1 represents the displacement of the mass block.

[0020] Compared with the related art, the beneficial effects of the present invention are:

[0021] The invention achieves the coupling of nonlinear stiffness and damping effect by installing an additional inertia container inside the X-shaped support, so as to enhance the vibration suppression performance. Moreover, through a comprehensive study on the influence of various parameters of the structure, the parameter optimization design is carried out in a targeted manner, so that the support structure has ideal nonlinear stiffness, nonlinear damping and nonlinear mass inertia, and the ultra-low natural frequency of the structure can be achieved, thereby improving the vibration isolation performance.

Brief Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0023] Figure 1 A three-dimensional diagram of the bionic support structure provided by the present invention;

[0024] Figure 2 A schematic diagram of a bionic support structure provided by the present invention;

[0025] Figure 3 A schematic diagram of a bionic support structure of two layers of X-shaped support monomers provided by the present invention;

[0026] Figure 4 for Figure 1 Reference diagram of the bionic support structure in use;

[0027] Figure 5 It is the structural diagram of the inertia container;

[0028] Figure 6 The structural parameters θ, L, n and F k -y1 nonlinear influence curve;

[0029] Figure 7 is the displacement transmissibility curve under different c;

[0030] Figure 8 A comparison curve between the bionic support structure provided by the present invention and a traditional vibration isolator. [Specific implementation method]

[0031] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention and to make the above-mentioned purposes, features and advantages of the present invention more obvious and understandable, the specific implementation modes of the present invention are further described below in conjunction with the drawings of the present application.

[0032] Please refer to Figure 1-8 The present invention provides a bionic support structure 100, including a base plate 10, an X-shaped support assembly 20, a connecting rod 30, a mass block 40, a first connecting member 50 and a second connecting member 60.

[0033] The X-shaped support assembly 20 includes at least one X-shaped support unit 21 arranged in a vertical direction. The X-shaped support unit 21 includes two force arms arranged in an X-shape, and the middle of the two force arms is hinged. When the X-shaped support unit 21 is subjected to force, the two force arms can rotate around the hinge point.

[0034] Each of the X-shaped supporting units 21 has two first connection points at the top and two second connection points at the bottom.

[0035] Please refer to Figure 1 and Figure 2 , the number of the connecting rods 30 is four, the lengths of the four connecting rods 30 are equal, the four connecting rods 30 are divided into two upper connecting rods 31 and two lower connecting rods 32, the top ends of the two upper connecting rods 31 are hinged to the same hinge point on the mass block 40, and the bottom ends are respectively hinged to the two first connection points at the top of the X-shaped support assembly 20; the bottom ends of the two lower connecting rods 32 are hinged to the same hinge point on the base plate 10, and the top ends are respectively hinged to the two second connection points at the bottom of the X-shaped support assembly 20; in each of the X-shaped support monomers 21, one of the first connecting members 50 and the second connecting members 60 is connected between the two first connection points, and the other of the first connecting members 50 and the second connecting members 60 is connected between the two second connection points, wherein the first connecting member 50 is an inertia container, and the second connecting member 60 includes a horizontal spring 61 and a damper 62 arranged in parallel.

[0036] by Figure 2 For example, after the connecting rods 30 are installed, the connecting rods 30 located at the upper and lower ends of the X-shaped support assembly 20 are symmetrical to each other, and the connecting rods 30 located at the left and right sides of the X-shaped support assembly 20 are symmetrical to each other.

[0037] Please refer to Figure 2 and Figure 3 , Figure 2 The number of the X-shaped support monomer 21 is 1, that is, the number of layers of the X-shaped support assembly 20 is 1; Figure 3 The number of the X-shaped support monomers 21 is 2, that is, the number of layers of the X-shaped support assembly 20 is 2. The number of layers of the X-shaped support assembly 20 is selected according to actual needs. When the number of the X-shaped support assembly 20 is multiple layers, it is only necessary to connect the first connection point of the lower X-shaped support monomer to the second connection point of the upper X-shaped support monomer correspondingly, and the connection method is hinged.

[0038] See also Figure 5 The inertia container 50 includes a housing 51 , a first gear 52 , a second gear 53 , a third gear 54 , a flywheel 55 and a rack 56 .

[0039] The housing 51 forms a receiving space, and the first gear 52 , the second gear 53 , the third gear 54 and the flywheel 55 are all received in the receiving space.

[0040] The first gear 52 and the second gear 53 are fixed, the third gear 54 and the flywheel 55 are fixed, and the second gear 53 and the third gear 54 are meshed. Preferably, the axes of the first gear 52 and the second gear 53 are located on the same straight line, and the axes of the third gear 54 and the flywheel 55 are located on the same straight line. The rack 56 is meshed with the first gear 52, and the end of the rack 56 is exposed through the housing 51 to form a first connection point. The housing 51 is provided with a second connection point at one end away from the first connection point. The inertia container 50 is connected to one end of the X-shaped support monomer 21 through the first connection point and the second connection point.

[0041] When a load is applied to the mass block 40, the X-shaped support assembly 20 is compressed, and the force arm in the X-shaped support unit 21 rotates around the hinge point. When the force arm moves, the states of the inertia container 50, the horizontal spring 61 and the damper 62 are all changed. Figure 4 For example, the dotted line represents the initial state of the bionic support structure 100, and the solid line represents the state of the bionic support structure 100 after being subjected to load. At this time, the mass block 40 generates a displacement of y1 downward. At this time, the X-shaped support monomer 21 is compressed, the distance between the two first connection points increases, and the distance between the two second connection points also increases. The inertia container 50, the horizontal spring 61 and the damper 62 are all stretched.

[0042] When the inertia container 50 is stretched, the rack 56 in the inertia container 50 moves outward, drives the first gear 52 to rotate, drives the second gear 53 and the third gear 54, and finally drives the flywheel 55 to rotate. The flywheel 55 has a large mass. The inertia container 50 converts the linear motion of the mass block 40 into the rotation of the flywheel 55, thereby utilizing the inertia generated by the flywheel 55 to transfer and consume energy from the system. When the inertia container 50 is compressed, the various components in the inertia container 50 move in the opposite direction, and can also drive the flywheel 55 to rotate to consume energy. Through the setting of the inertia container 50, the coupling of the nonlinear stiffness and damping effect of the system is achieved, thereby enhancing the vibration suppression performance.

[0043] The present invention also provides an optimization design method for the above bionic support structure, comprising the following steps:

[0044] S1: constructing a dynamic model of the bionic support structure, selecting θ, L, and n as parameters to be optimized, wherein θ represents the initial angle of the connecting rod relative to the horizontal plane, L is the length of the connecting rod, and n is the number of the X-shaped support monomers;

[0045] The kinetic model is expressed as:

[0046]

[0047]

[0048] In the formula, represents the vertical acceleration of the mass block, represents the vertical velocity of the mass block, represents the basic excitation acceleration of the mass block, c represents the damping coefficient of the damper, k represents the stiffness of the horizontal spring, F in1 and F in2 represents the inertial force of the bionic support structure, F c is the damping force of the bionic support structure, F k is the stiffness force of the bionic support structure, β is the ratio of the effective mass of the inertia container to the mass of the mass block, and y1 represents the displacement of the mass block.

[0049] S2: The three parameters are divided into two static parameters and one dynamic parameter by using the control variable method, a fixed value is assigned to the static parameter, the value of the dynamic parameter is adjusted within the design range, and the stiffness force F of the bionic support structure is output based on the dynamic model. k The displacement y1 of the mass block is k -y1 curve, traverses the entire design range of the dynamic parameters, and obtains F under different values ​​of the dynamic parameters k-y1 curve, select the F with the best forward nonlinear result k -The dynamic parameter value corresponding to the y1 curve is taken as the optimal value, and the classification of static parameters and dynamic parameters is adjusted to obtain the optimal values ​​of the three parameters respectively.

[0050] S3: Construct a displacement transfer model of the bionic support structure, expressed as:

[0051]

[0052]

[0053] In the formula, |·| represents the norm, A is the amplitude of the bionic support structure, φ is the phase angle, A0 is the basic excitation amplitude, Ω is the dimensionless excitation frequency, τ is dimensionless time, τ=ω1t, ω is the basic excitation frequency, ω1 is the natural frequency of the bionic support structure, ξ n is the equivalent damping ratio of the bionic support structure, f c is the nonlinear damping expanded by Taylor series, c is the damping coefficient of the damper, and M represents the mass of the mass block;

[0054] S4: Use the best value Complete the construction of the dynamic model, adjust the value of c, and calculate the structural displacement transfer rate T of the bionic support structure under different values. d , and the structural displacement transmissibility T is obtained d The curve with the smallest resonance peak and the lowest resonance frequency is selected as the optimal value of c, which is expressed as the optimal value Complete the process of optimizing design.

[0055] The bionic support structure obtained according to the parameters of the optimized combination has good nonlinear inertia, nonlinear damping, nonlinear stiffness and low natural frequency, and at the same time has a small displacement transmission rate, thereby ensuring stable performance of the structure under large excitation and improving the overall vibration isolation performance.

[0056] Example 1

[0057] In this embodiment, β=0.2, the design range of L is (0.075, 0.1, 0.125), and the design range of θ is The design range of n is (2, 3, 4), and the design range of c is (20, 30, 40, 50).

[0058] Let L = 0.1, n = 2, adjust the value of θ, and get F k -y1 curve such as Figure 6 As shown in (a), Figure 6It can be seen from (a) that when When the corresponding curve has the best positive nonlinear performance, so the optimal value is selected

[0059] make n=2, adjust the value of L within the design range, and obtain F k -y1 curve such as Figure 6 As shown in (b), Figure 6 As can be seen from (b), when L = 0.1, the corresponding curve has the best positive nonlinear performance, so the optimal value is selected

[0060] Let L = 0.1, Adjust the value of n to get F k -y1 curve such as Figure 6 As shown in (c), from Figure 6 As can be seen from (c), when n = 2, the corresponding curve has the best positive nonlinear performance, so the optimal value is selected

[0061] Using β = 0.2, After completing the construction of the kinetic model, take A0 = 0.5, adjust the value of c within the design range, and obtain T d -Ω curve is as follows Figure 7 As shown, from Figure 7 It can be seen that when c = 50, the corresponding curve resonance frequency and resonance peak are the smallest, so the optimal value is selected

[0062] See also Figure 8 , Figure 8 To use the optimal value The corresponding curve comparison diagram of the produced bionic support structure and the traditional shock absorber shows from the response curve that the bionic support structure provided by the present invention can maintain stable seismic isolation performance under large amplitude excitation. Under the same cubic stiffness and the same excitation amplitude, the traditional QZS isolator exhibits obvious nonlinear phenomena that are not conducive to vibration reduction, such as jumping and bistability, which leads to a considerable unstable area in the vibration isolation frequency domain, resulting in a reduction in the bandwidth of the vibration isolation frequency band, and a significant reduction in the vibration isolation performance in the ultra-low frequency region, endangering the stability of the structure. In contrast, the vibration isolation performance of the bionic support structure of the present invention has been significantly enhanced. In short, the proposed optimized vibration reduction design of a bionic support structure equipped with an inertial container enables the structure to have a wider isolation frequency range, a lower resonance amplitude, ensure stability, adjustable load capacity and resonance frequency, and show superior vibration isolation performance.

[0063] Compared with the related art, the beneficial effects of the present invention are:

[0064] The present invention installs an additional inertia container inside the X-shaped support to achieve the coupling of nonlinear stiffness and damping effect, thereby enhancing the vibration suppression performance. By comprehensively studying the influence of various parameters of the structure, the parameter optimization design is carried out in a targeted manner, so that the support structure has ideal nonlinear stiffness, nonlinear damping and nonlinear mass inertia, and the ultra-low natural frequency of the structure can be achieved, thereby improving the vibration isolation performance.

[0065] The embodiments of the present invention are described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations made to these embodiments without departing from the principles and spirit of the present invention are still within the protection scope of the present invention.

Claims

1. A bionic support structure, characterized in that: The invention comprises a bottom plate, an X-shaped support assembly, a connecting rod, a mass block, a first connecting member and a second connecting member, wherein the X-shaped support assembly comprises at least one X-shaped support monomer arranged in a vertical direction, wherein the top of each X-shaped support monomer is provided with two first connecting points, and the bottom of each X-shaped support monomer is provided with two second connecting points; the number of the connecting rods is four, and the lengths of the four connecting rods are equal, and the four connecting rods are divided into two upper connecting rods and two lower connecting rods, wherein the tops of the two upper connecting rods are hinged to the same hinge point on the mass block, and the bottoms are respectively hinged to the two first connecting points at the top of the X-shaped support assembly; the bottoms of the two lower connecting rods are hinged to the same hinge point on the bottom plate, and the tops are respectively hinged to the two second connecting points at the bottom of the X-shaped support assembly; in each X-shaped support monomer, one of the first connecting member and the second connecting member is connected between the two first connecting points, and the other of the first connecting member and the second connecting member is connected between the two second connecting points, wherein the first connecting member is an inertia container, and the second connecting member comprises a horizontal spring and a damper arranged in parallel.

2. The bionic support structure according to claim 1, characterized in that: The X-shaped support monomer includes two force arms arranged crosswise in an X shape, and the middle of the two force arms is hinged.

3. The bionic support structure according to claim 1, characterized in that: The inertia container includes a shell, a first gear, a second gear, a third gear, a flywheel and a rack. The shell forms a receiving space, and the first gear, the second gear, the third gear and the flywheel are all received in the receiving space; the first gear and the second gear are fixed, the third gear and the flywheel are fixed, the second gear and the third gear are meshed, the rack is meshed with the first gear, and the end of the rack passes through the shell and is exposed to form a first connection point. A second connection point is provided at one end of the shell away from the first connection point, and the inertia container is connected to the first connection member through the first connection point and the second connection point.

4. The bionic support structure according to claim 3, characterized in that: The axes of the first gear and the second gear are located on the same straight line, and the axes of the third gear and the flywheel are located on the same straight line.

5. An optimization design method for a bionic support structure according to any one of claims 1 to 4, characterized in that: The steps include: S1: constructing a dynamic model of the bionic support structure, selecting θ, L, and n as parameters to be optimized, wherein θ represents the initial angle of the connecting rod relative to the horizontal plane, L is the length of the connecting rod, and n is the number of the X-shaped support monomers; S2: The three parameters are divided into two static parameters and one dynamic parameter by using the control variable method, a fixed value is assigned to the static parameter, the value of the dynamic parameter is adjusted within the design range, and the stiffness force F of the bionic support structure is output based on the dynamic model. k The displacement y1 of the mass block is k -y1 curve, traverses the entire design range of the dynamic parameters, and obtains F under different values ​​of the dynamic parameters k -y1 curve, select the F with the best forward nonlinear result k -The dynamic parameter value corresponding to the y1 curve is taken as the optimal value, and the classification of static parameters and dynamic parameters is adjusted to obtain the optimal values ​​of the three parameters respectively. S3: Construct a displacement transfer model of the bionic support structure, expressed as: In the formula, |·| represents the norm, A is the amplitude of the bionic support structure, φ is the phase angle, A0 is the basic excitation amplitude, Ω is the dimensionless excitation frequency, τ is dimensionless time, τ=ω1t, ω is the basic excitation frequency, ω1 is the natural frequency of the bionic support structure, ξ n is the equivalent damping ratio of the bionic support structure, c is the damping coefficient of the damper, and f c is the nonlinear damping of Taylor series expansion, M represents the mass of the mass block; S4: Use the best value Complete the construction of the dynamic model, adjust the value of c, and calculate the structural displacement transfer rate T of the bionic support structure under different values. d , and the structural displacement transmissibility T is obtained d The curve with the smallest resonance peak and the lowest resonance frequency is selected as the optimal value of c, which is expressed as the optimal value Complete the process of optimizing design.

6. The optimization design method according to claim 5, characterized in that: The kinetic model is expressed as: In the formula, represents the vertical acceleration of the mass block, represents the vertical velocity of the mass block, represents the base excitation acceleration of the mass block, k represents the stiffness of the horizontal spring, F in1 and F in2 represents the inertial force of the bionic support structure, F c is the damping force of the bionic support structure, F k is the stiffness force of the bionic support structure, β is the ratio of the effective mass of the inertia container to the mass of the mass block, and y1 represents the displacement of the mass block.

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