A magneto-rheological elastomer vibration isolation system with rigid-flexible coupling self-sensing function

Abstract

The application discloses a magnetorheological elastomer vibration isolation system with rigid-flexible coupling self-sensing function, which comprises a rigid-flexible coupling structure, a magnetic field generating device and a friction nanogenerator vibration sensor. In a vibration environment, the friction nanogenerator vibration sensor generates a voltage signal, and a single-chip microcomputer collects the signal to analyze a vibration frequency to control the application of the magnetic field, so that intelligent modulation of the vibration is realized. The application provides a magnetorheological elastomer with a rigid-flexible coupling structure, improves the compression bearing capacity of the magnetorheological elastomer, and makes the frequency shift range of the rigid-flexible coupling magnetorheological elastomer vibration isolator wider and the vibration reduction effect better than that of a pure MRE vibration isolator. The friction nanogenerator is integrated in the vibration isolation system as a vibration sensor to monitor external vibration and realize self-sensing function, without the need of an external sensor and power supply, so that the system complexity and cost are reduced. The application has the characteristics of simple structure, high bearing capacity, wide monitoring range and obvious vibration reduction effect.

Description

Technical Field

[0001] This invention belongs to the field of smart material vibration isolation, and in particular, it is a magnetorheological elastomer vibration isolation system with rigid-flexible coupling self-sensing function. Background Technology

[0002] Vibration is a common phenomenon in nature and an unavoidable problem in the field of engineering. Vibration is fundamental to the operation of communications, broadcasting, television, and radar. It can be used to sort items of different weights and sizes, and beneficial vibrations can improve working conditions and bring great convenience. However, in many cases, vibration brings more adverse effects. Vibration can affect the function of precision instruments and equipment, reduce machining accuracy and surface finish, and exacerbate component fatigue and wear. Vibration can also cause large structural deformations; some buildings and bridges have collapsed due to vibration. Beneficial vibrations should be utilized to improve labor productivity, while harmful vibrations should be avoided or even eliminated as much as possible.

[0003] To minimize the harm caused by harmful vibrations, vibration isolation devices can be placed between the vibration source and the vibrating mechanical system to reduce the system's response to vibration. Currently, vibration isolation can be mainly divided into passive, active, and semi-active vibration isolation. Passive vibration isolation, such as using rubber pads or springs, reduces the transmission of vibration and noise, but its effectiveness decreases significantly with changes in vibration conditions, resulting in poor adaptability. Some active vibration isolation systems, in order to achieve better vibration isolation and broaden the isolation frequency band, use sensors to monitor external vibration information. This leads to increased system complexity and space costs, and places higher demands on the control system. Semi-active vibration reduction is a method between active and passive vibration reduction. It uses a control system to regulate vibration, utilizing smart materials or controllers to control the stiffness and damping coefficient of the vibration damper, thereby reducing vibration. This method is more energy-efficient than active vibration reduction and has a better vibration reduction effect than passive vibration reduction.

[0004] Magnetorheological elastomers (MEAs), as intelligent materials with variable modulus, can precisely adjust their stiffness and natural frequency using an external magnetic field. Therefore, mechanical systems subjected to vibration can effectively avoid resonance with external vibration sources after a magnetic field is applied, achieving vibration reduction. Semi-active vibration isolators based on MEAs have been widely used in buildings, bridges, vehicles, and other fields. The vibration reduction effect of vibration modulation systems is closely related to the performance of MEAs. Currently, the load-bearing capacity of MEA vibration isolators is limited by the matrix material used, and the stiffness variation and frequency shift range are restricted, making it difficult to efficiently adjust the resonant frequency of the isolator. Furthermore, to achieve better vibration reduction, vibration isolators generally need to be combined with external sensors to collect external vibration information and the vibration state of the isolator itself. Without external sensors, it is difficult to achieve self-monitoring and control of vibration. How to improve load-bearing capacity and collect external vibration information to achieve better vibration isolation effects is an urgent problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a magnetorheological elastomer vibration isolation system with rigid-flexible coupling self-sensing function, so as to improve the load-bearing capacity of the magnetorheological elastomer, broaden the frequency shift range of the vibration isolation system, and improve the vibration isolation effect of the vibration isolation system.

[0006] The technical solution to achieve the purpose of this invention is as follows:

[0007] A magnetorheological elastic vibration isolation system with rigid-flexible coupling self-sensing function includes a rigid-flexible coupling structure, a magnetic field generating device, and a triboelectric nanogenerator vibration sensor, wherein:

[0008] The rigid-flexible coupling structure includes a magnetorheological elastomer and an octagonal structure filled within the magnetorheological elastomer.

[0009] The magnetic field generating device includes a magnetic core, a copper coil, and an outer housing. The magnetic core is placed on the upper and lower sides of a rigid-flexible coupling structure composed of an octagonal structure and a magnetorheological elastic body, and is fixed to the rigid-flexible coupling structure. The copper coil is built into the interior of the outer housing.

[0010] The triboelectric nanogenerator vibration sensor is composed of an electropositive material and an electronegative material. One material is wrapped around the rigid-flexible coupling structure and the magnetic core, while the other material is used as the winding of the copper coil. The two materials constitute a set of triboelectric nanogenerators, which can generate relative frictional motion in a vibration environment to generate voltage signals.

[0011] The magnetic core and outer shell are used to form a closed magnetic circuit. When the copper coil is energized, it can generate a magnetic field parallel to the vibration direction, and the magnetic field direction is perpendicular to the upper and lower planes of the magnetorheological elastic body.

[0012] The significant advantages of this invention compared to existing technologies are:

[0013] (1) By adding an octet structure to the magnetorheological elastomer to prepare a rigid-flexible coupled magnetorheological elastomer, the compressive bearing capacity of the sample can be improved.

[0014] (2) The frequency shift range of the magnetorheological elastomer vibration isolator with rigid-flexible coupling structure is larger than that of the pure magnetorheological elastomer vibration isolator, and the vibration isolation effect is better.

[0015] (3) The triboelectric nanogenerator is integrated inside the vibration isolation system as a vibration sensor. It can generate a voltage signal when vibrating. The voltage signal is collected by a microcontroller and the frequency is analyzed. It can realize the perception of external vibration and achieve intelligent vibration isolation. The triboelectric nanogenerator is self-powered and does not require a power supply. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the magnetorheological elastomer vibration isolation system with rigid-flexible coupling self-sensing function of the present invention.

[0017] Figure 2 This is a schematic diagram of the flexible-rigid-flexible coupled magnetorheological elastic body and octagonal body structure of the present invention.

[0018] Figure 3 This is a schematic diagram showing the hydrostatic test results of the rigid-flexible coupled magnetorheological elastomer and the pure magnetorheological elastomer of the present invention.

[0019] Figure 4 This is a schematic diagram showing the experimental results of the frequency shift characteristics of the rigid-flexible coupled magnetorheological elastomer vibration isolator and the pure magnetorheological elastomer vibration isolator of the present invention.

[0020] Figure 5 This is a flowchart illustrating the operation of the magnetorheological elastomer vibration isolation system with rigid-flexible coupling self-sensing function of the present invention.

[0021] In the diagram: 1. Octagonal structure; 2. Magnetorheological elastomer; 3. Magnetic core; 4. Copper coil; 5. Outer shell; 6. Copper foil; 7. PTFE mold; 8. Microcontroller; 9. MOSFET; 10. DC power supply; 11. Accelerometer; 12. Data acquisition card; 13. Computer Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0023] Please see Figures 1-5 The present invention provides a technical solution: a magnetorheological elastomer vibration isolation system with rigid-flexible coupling self-sensing function, which integrates a magnetorheological elastomer with rigid-flexible coupling structure and a triboelectric nanogenerator sensor. Figure 1This is a schematic diagram of the magnetorheological elastomer vibration isolation system with rigid-flexible coupling self-sensing function of the present invention. The vibration isolation system can be divided into three parts: a rigid-flexible coupling structure, a magnetic field generating device, and a triboelectric nanogenerator sensor, wherein:

[0024] See Figure 1 and Figure 2 The rigid-flexible coupling structure includes an octagonal structure 1 and a magnetorheological elastomer 2. The octagonal structure 1 is printed using photopolymerization 3D printing, and then embedded in the magnetorheological elastomer 2. After curing and demolding, the rigid-flexible magnetorheological elastomer is prepared. (See also...) Figure 1 and Figure 3 The magnetic field generating device includes a magnetic core 3, a copper coil 4, and an outer shell 5. The magnetic core 3 is placed on the upper and lower sides of a rigid-flexible coupling structure composed of an octet structure 1 and a magnetorheological elastomer 2, and is fixed with silicone rubber. The copper coil 4 is built into the outer shell 5. The triboelectric nanogenerator vibration sensor is composed of electropositive and electronegative materials. One material is wrapped around the rigid-flexible coupling structure and the magnetic core, with copper foil 6 selected as the positive electrode. The other material is used as the winding mold for the copper coil, with PTFE mold 7 selected as the negative electrode. Under vibration, the copper foil 6 and PTFE mold 7 undergo relative frictional motion to generate a voltage signal, which is led out using wires on the surface of the copper foil 6.

[0025] The described magnetorheological elastomer vibration isolation system with rigid-flexible coupling self-sensing function has a rigid-flexible coupling structure at the center of the entire system, a magnetic field generating device on the outermost side, and a triboelectric nanogenerator vibration sensor placed between the two. The octagonal structure 1 in the rigid-flexible coupling structure has a high modulus and is a metamaterial structure with tensile and compressive properties. Under compression, it can deform and absorb energy, playing a "rigid" role in the rigid-flexible coupling structure. The magnetorheological elastomer 2 uses silicone rubber with a low elastic modulus as the elastomer matrix, playing a "flexible" role in the rigid-flexible coupling structure. The outer beam of the octagonal structure 1 has a length L, the inner beam has a length l, and the rod diameter is D, with an aspect ratio L / D ranging from 15 to 30. Oct-MRE-15 is used to denote a rigid-flexible coupled magnetorheological elastomer with an aspect ratio L / D of 15, and so on. See also... Figure 3 The static pressure test results showed that, compared with pure magnetorheological elastomers, the three rigid-flexible coupled magnetorheological elastomers exhibited larger normal forces under the same compressive strain, indicating that the rigid-flexible coupled magnetorheological elastomers had better compressive bearing capacity. (See also...) Figure 4The frequency shift characteristic experiment results show that, under the same current, the three rigid-flexible coupled magnetorheological elastomers have a larger frequency shift range, which is beneficial to improving the vibration isolation effect of the vibration isolator. In the magnetic field generating device, the copper coil 4 is uniformly wound on the polytetrafluoroethylene mold 7. The magnetic core 3 and the outer shell 5 form a closed magnetic circuit, and can generate an approximately uniform magnetic field in the central part, parallel to the vibration direction and perpendicular to the upper and lower planes of the magnetorheological elastomer 2. During vibration modulation, the magnitude of the magnetic field acting on the magnetorheological elastomer 2 can remain stable. (See also...) Figure 1 The magnetorheological elastomer vibration isolation system with rigid-flexible coupling self-sensing function integrates a triboelectric nanogenerator sensor. It relies on external vibration to force the copper foil 6 and the polytetrafluoroethylene mold 7 to rub against each other, generating a voltage signal that can be used to analyze the external vibration state. Moreover, the triboelectric nanogenerator vibration sensor does not require an external power supply.

[0026] The working principle of this invention is as follows:

[0027] Please see Figure 1 and Figure 5The specific working principle of this invention is as follows: External vibration forces the copper foil 6 and the polytetrafluoroethylene mold 7 in the vibration isolation system to move relative to each other. The two materials have different electronegativity, forming a set of triboelectric nanogenerators. Under external vibration, these nanogenerators can output voltage signals, thus serving as vibration sensors. The vibration signal is acquired by the GPIO port of the microcontroller 8. The specific sampling pin is determined based on the input pin of the digital-to-analog converter module, and this port is defined as the analog input. The sampling frequency and sampling time are set. According to the Nyquist sampling theorem, for a continuous-time signal with finite bandwidth, the sampling frequency must be at least twice the signal bandwidth to accurately recover the original signal. The current vibration frequency is obtained by calling the Fast Fourier Transform function, and the application of a magnetic field for vibration modulation is controlled based on the frequency. When the external vibration frequency is the resonant frequency, the entire system is in a resonant state, and the energy transmitted into the system is large. The microcontroller 8 analyzes and collects the signal, calculates the vibration frequency as the resonant frequency, and outputs a high-level signal to turn on the MOSFET 9. The DC power supply 10 supplies power to the copper coil 4, providing a magnetic field. An approximately uniform magnetic field is formed at the rigid-flexible coupled magnetorheological elastic body, changing the stiffness to shift the resonant frequency of the vibration isolation system to the right, avoiding resonance and thus achieving vibration modulation. The microcontroller 8 can monitor the external vibration state in real time by collecting the signal from the triboelectric nanogenerator. When the external vibration moves away from the resonant frequency, the microcontroller 8 outputs a low-level signal to turn off the MOSFET 9, the DC power supply 10 stops supplying power, and the magnetic field disappears. The vibration isolation system can perform intelligent vibration isolation control according to the external vibration frequency. In this invention, an accelerometer 11 can be used above the vibration isolation system to connect to a data acquisition card 12 to collect acceleration signals before and after vibration modulation, which can then be connected to a computer 13 for display to observe the vibration isolation effect.

Claims

1. A magnetorheological elastic body vibration isolation system with rigid-flexible coupling self-sensing function, characterized in that, This includes a rigid-flexible coupling structure, a magnetic field generating device, a triboelectric nanogenerator vibration sensor, and a microcontroller, among which: The rigid-flexible coupling structure includes a magnetorheological elastomer and an octagonal structure filled within the magnetorheological elastomer. The magnetic field generating device includes a magnetic core, a copper coil, and an outer shell. The magnetic core is placed on the upper and lower sides of a rigid-flexible coupling structure composed of an octagonal body structure and a magnetorheological elastic body, and is fixed to the rigid-flexible coupling structure. The copper coil is built into the outer shell. The triboelectric nanogenerator vibration sensor is composed of an electropositive material and an electronegative material. One material is wrapped around the rigid-flexible coupling structure and the magnetic core, while the other material serves as the winding mold for the copper coil. The two materials constitute a set of triboelectric nanogenerators, which can generate relative frictional motion in a vibration environment to produce a voltage signal. The microcontroller is used to acquire the voltage signal generated by the triboelectric nanogenerator vibration sensor to obtain the current vibration frequency. The magnetic core and outer shell are used to form a closed magnetic circuit. When the copper coil is energized, it can generate a magnetic field parallel to the vibration direction, and the magnetic field direction is perpendicular to the upper and lower planes of the magnetorheological elastic body.

2. The magnetorheological elastic vibration isolation system with rigid-flexible coupling self-sensing function according to claim 1, characterized in that, It also includes MOSFETs and DC power supplies; When the external vibration frequency is at the resonant frequency, the microcontroller outputs a signal to turn on the MOSFET, and the DC power supply powers the copper coil to generate a magnetic field. When the external vibration moves away from the resonant frequency, the microcontroller outputs a signal to turn off the MOSFET, the DC power supply stops supplying power, and the magnetic field disappears.

3. The magnetorheological elastic vibration isolation system with rigid-flexible coupling self-sensing function according to claim 1, characterized in that, The octagonal structure was printed using photopolymerization 3D printing, and then embedded in a magnetorheological elastomer. After curing and demolding, a rigid-flexible coupled magnetorheological elastomer was prepared.

4. The magnetorheological elastic vibration isolation system with rigid-flexible coupling self-sensing function according to claim 1, characterized in that, The electropositive material is made of copper foil, and the electronegative material is made of polytetrafluoroethylene.

5. The magnetorheological elastic vibration isolation system with rigid-flexible coupling self-sensing function according to claim 1, characterized in that, The outer beam of the octagonal structure has a length of L, the inner beam has a length of l, and the length-to-diameter ratio L / D is between 15 and 30, where D is the diameter of the beam.

6. The magnetorheological elastic vibration isolation system with rigid-flexible coupling self-sensing function according to claim 1, characterized in that, It also includes an accelerometer, a data acquisition card, and a computer connected in sequence; The accelerometer is used to detect acceleration signals before and after vibration modulation, and transmits them to a computer via a data acquisition card to display the vibration isolation effect.

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