Particle-elastomer coupled vibration system local phase state identification method and experimental device

Abstract

The invention provides a particle-elastomer coupled vibration system local phase state identification method and an experimental device, and relates to the technical field of particle-elastomer coupled vibration. According to the method, the particle medium is locally driven by applying constant-amplitude frequency sweeping excitation to the elastomer, and meanwhile, the immersed elastomer serves as a probe / sensor and is used for judging the phase state change of the particle medium. Through establishment of a coupling system theoretical model and experimental verification, the dynamic parameters such as the dynamic effective mass of the vibration elastomer in the immersed particles and the particle local phase calibration relation are obtained, and therefore the purpose that the elastomer serves as a driving-sensing integrated device to recognize the particle local phase is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of particle-elastic body coupling vibration, and in particular to a local phase state identification method and an experimental device for a particle-elastic body coupling vibration system. Background Art

[0002] Existing studies have shown that when a fluid vibrates in coupling with a structure, it can be simplified as an added mass effect. However, compared with fluid media, when granular matter vibrates in coupling with an elastic body, the elastic body and its neighboring granular media often exhibit very complex dynamic characteristics. Researchers' studies on the dynamic behavior of granular matter mostly input energy from the outside through vibration or shear of rigid boundaries. When granular matter vibrates in coupling with an elastomer, especially an immersed elastomer, it will exhibit more complex additional effects or nonlinear behaviors, and the local phase characteristics inside the three-dimensional granular matter cannot be directly observed by experimental means.

[0003] In the field of engineering, the effect of particles on the dynamic performance of elastic structures, such as particle dampers and foundation beams, is a widely-regarded issue, but there is still a lack of a unified theoretical model and experimental verification. Therefore, it is very difficult to establish a simple and effective model for the particle-elastic coupling system to identify and detect the local phase state of the system. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a method and experimental device for identifying the local phase state of a particle-elastomer coupled vibration system; the method is implemented through an integrated drive-sensor approach, and the local phase state characteristics or local phase state changes of the particle material are identified through the strain signal of the elastomer. Therefore, for the study of the local phase state characteristics of the particle material, the vibrating elastomer is both a driver, driving the particle material to undergo local phase changes, and a sensor, detecting the local phase state characteristics of the particle material through its own signal.

[0005] Driving is achieved by applying simple harmonic excitations at different force amplitudes and frequencies to the elastic body, causing the elastic body to vibrate and drive neighboring particles. Sensing is achieved by identifying the local phase characteristics of particles through the elastic body vibration morphology (strain-displacement reconstruction method) and nonlinear vibration characteristics (jump, chaos, bifurcation, etc.) obtained by the dynamic strain signal on the elastic body (which can be a certain number of evenly distributed strain sensors). Elastic bodies, such as beams, need to be calibrated as sensors. The DEM-FEM coupled numerical calculation method is used, combined with experiments, to verify each other to calibrate specific elastic bodies.

[0006] The technical solution of the present invention is as follows:

[0007] On the one hand, an experimental device for local phase identification of a particle-elastic body coupled vibration system includes a glass box, a particle medium, a hollow elastic body, a wireless force sensor, a wireless acceleration sensor, and a wireless remote control linear motor;

[0008] The wireless remote control linear motor is installed inside the hollow elastic body, the wireless force sensor is installed inside the hollow elastic body and above the wireless remote control linear motor, and the wireless acceleration sensor is installed on the lower surface inside the hollow elastic body;

[0009] The outer surface of the hollow elastic body is regular;

[0010] The glass box is firmly connected to the workbench, and the hollow elastic body is placed in the glass box as a free boundary;

[0011] The hollow elastic body is a split structure, and the outer shell of the hollow elastic body is formed by buckling two identical parts;

[0012] On the other hand, a method for identifying a local phase state of a particle-elastic body coupled vibration system is implemented based on the above-mentioned particle-elastic body coupled vibration system local phase state identification experimental device, and specifically includes the following steps:

[0013] Step 1: Use DEM-FEM coupling calculation method to establish a numerical simulation model;

[0014] Step 2: Get the calibration dataset:

[0015] Step 2.1: Under the same particle size and particle layer thickness, control the amplitude of the exciting force on the hollow elastic body, adjust the exciting frequency from small to large and from large to small, obtain the amplitude-frequency characteristic curves of the two frequency sweep paths, and extract the effective friction coefficient μ, inertia number I and elastic body strain of the granular medium during the vibration process;

[0016] Step 2.2: Change the excitation force amplitude, repeat step 2.1, and perform two sets of repeated experiments;

[0017] Step 2.3: Change the thickness of the particle layer and repeat steps 2.1-2.2;

[0018] Step 2.4: Change the particle size and repeat steps 2.1 to 2.3;

[0019] Step 2.5: Construct a calibration data set using the obtained elastic body strain, effective friction coefficient, and inertia number data;

[0020] Step 3: According to the elastic body strain, effective friction coefficient μ and inertia number I extracted from each working condition and the corresponding excitation, data fitting is performed to form a relationship function or curve between excitation-elastic body strain-particle rheology, and the local phase state of the particle is detected by strain.

[0021] The beneficial effects of adopting the above technical solution are:

[0022] 1. A method for measuring the local phase state of granular media is proposed, which solves the problem of difficulty in obtaining the phase state of particles when the elastic body and particles are coupled to vibrate;

[0023] 2. Drive-sensor integration: The hollow beam is both a drive and a sensor. Integrating the sensor inside the drive will not change the state of the particle system under local drive, eliminating the system error caused by implanting the sensor in conventional testing;

[0024] 3. Use wireless sensor design to reduce the impact of additional boundaries and sensor connections on granular media brought by wired design, improve recognition accuracy and reduce errors;

[0025] 4. Numerical simulation and physical experiments are used simultaneously to verify each other, making the method more reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of a physical experiment model in an embodiment of the present invention;

[0027] In the figure, 1-glass box, 2-glass beads, 3-hollow beam;

[0028] Figure 2 The internal structure of the hollow beam in the embodiment of the present invention;

[0029] In the figure, 4-wireless remote control linear motor;

[0030] Figure 3 A schematic diagram of a numerical simulation model in an embodiment of the present invention;

[0031] Figure 4 The amplitude-frequency characteristic curve and μ-I rheological relationship diagram in the prior art research in the embodiment of the present invention;

[0032] in Figure 4 (a) is the amplitude-frequency characteristic curve, Figure 4 (b) is the μ-I rheological relationship diagram; DETAILED DESCRIPTION

[0033] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0034] This experimental method mainly studies the nonlinear vibration of the particle-beam coupling system by focusing on parameters such as the exciting force amplitude, exciting force frequency, thickness of the particle layer in the beam area, and particle size. Among them, the elastic body not only implements local oscillation on the neighboring particles, but also serves as a probe to identify the additional effects of the granular medium and its phase state.

[0035] On the one hand, an experimental device for local phase identification of a particle-elastic body coupled vibration system includes: a glass box, a particle medium, a hollow elastic body (a soft metal or composite material plate, a beam, etc.), a wireless force sensor, a wireless acceleration sensor, and a wireless remote control linear motor;

[0036] The wireless remote control linear motor is installed inside the hollow elastic body, the wireless force sensor is installed inside the hollow elastic body and above the wireless remote control linear motor, and the wireless acceleration sensor is installed on the lower surface inside the hollow elastic body;

[0037] The outer surface of the hollow elastomer is regular, and there is no additional boundary such as measuring instruments to change the shape of the outer surface of the elastomer, which will not affect the state of the granular medium, and is convenient for theoretical modeling.

[0038] The glass box is firmly connected to the workbench, and the hollow elastic body is placed in the glass box as a free boundary;

[0039] The hollow elastic body acts as a driver to locally drive the granular medium. The elastic body drives the neighboring particles through its own vibration, which is different from the vibration of the entire box to drive the particle system. It also acts as a probe / sensor to qualitatively determine the phase change of the granular medium.

[0040] The hollow elastic body is a split structure, and the outer shell of the hollow elastic body is formed by buckling two identical parts, which is convenient for disassembling and assembling the linear motor. The wireless remote control linear motor is fixed inside the hollow elastic body through ribs.

[0041] The experimental setup in this example is as follows Figure 1 As shown in Figure 1, the basic framework of the particle-elastic body coupling vibration system experiment is shown. The hollow elastic body uses a hollow beam 3, such as Figure 2 As shown, the granular medium uses glass beads 2, the wireless remote-controlled linear motor 4 uses a linear vibrator, and the hollow beam is horizontally placed in the center of the glass box 1; in order to explore the size effect of the granular medium, three different sizes of glass beads are used in the experiment, and the particle size approximately obeys the normal distribution.

[0042] The linear exciter fixed in the hollow beam applies simple harmonic excitation in the vertical direction to the hollow beam, with a sweep frequency range from 0Hz to 500Hz; a wireless force sensor is installed on the upper surface of the hollow beam, just above the linear exciter, to measure the force signal; a wireless acceleration sensor is installed at the bottom of the hollow beam cavity just below the linear exciter to measure the acceleration signal; the force signal and acceleration signal are recorded and analyzed through the signal receiver and computer. Among them, the mass of the wireless remote control linear motor, wireless force sensor and wireless acceleration sensor is taken into account in the numerical modeling of the beam, thereby improving the calculation accuracy of the numerical model.

[0043] On the other hand, a method for identifying a local phase state of a particle-elastic body coupled vibration system is implemented based on the above-mentioned particle-elastic body coupled vibration system local phase state identification experimental device, and specifically includes the following steps:

[0044] Step 1: Use DEM-FEM coupling calculation method to establish a numerical simulation model;

[0045] The numerical simulation model in this embodiment is as follows Figure 3 As shown in the figure, the effectiveness of the numerical simulation results is verified by comparing with the test results of typical working conditions.

[0046] Step 2: Get the calibration dataset:

[0047] Step 2.1: Under the same particle size and particle layer thickness, control the amplitude of the exciting force on the hollow elastic body, adjust the exciting frequency from small to large and from large to small, obtain the amplitude-frequency characteristic curves of the two frequency sweep paths, and extract the effective friction coefficient μ, inertia number I and elastic body strain of the granular medium during the vibration process;

[0048] Step 2.2: Change the excitation force amplitude, repeat step 2.1, and perform two sets of repeated experiments;

[0049] Step 2.3: Change the thickness of the particle layer and repeat steps 2.1-2.2;

[0050] Step 2.4: Change the particle size and repeat steps 2.1 to 2.3;

[0051] Step 2.5: Construct a calibration data set using the obtained elastic body strain, effective friction coefficient, and inertia number data;

[0052] Step 3: According to the elastic body strain, effective friction coefficient μ and inertia number I extracted from each working condition and the corresponding excitation, data fitting is performed to form a relationship function or curve between excitation-elastic body strain-particle rheology, and the local phase state of the particle is detected by strain. Figure 4 In this embodiment, the amplitude-frequency characteristic curve is as follows: Figure 4 (a) shows the μ-I rheological relationship diagram. Figure 4 (b) as shown.

[0053] The above description is only a preferred embodiment of the present disclosure and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the embodiments of the present disclosure is not limited to the technical solutions formed by a specific combination of the above-mentioned technical features, but should also cover other technical solutions formed by any combination of the above-mentioned technical features or their equivalent features without departing from the above-mentioned inventive concept. For example, the above-mentioned features are replaced with the technical features with similar functions disclosed in the embodiments of the present disclosure (but not limited to) to form a technical solution.

Claims

1. An experimental device for identifying local phase states of a particle-elastic body coupled vibration system, characterized in that: Including glass box, granular medium, hollow elastic body, wireless force sensor, wireless acceleration sensor, wireless remote control linear motor; The wireless remote control linear motor is installed inside the hollow elastic body, the wireless force sensor is installed inside the hollow elastic body and above the wireless remote control linear motor, and the wireless acceleration sensor is installed on the lower surface inside the hollow elastic body.

2. The local phase state identification experimental device of a particle-elastic body coupled vibration system according to claim 1 is characterized in that: The outer surface of the hollow elastic body is regular.

3. The local phase state identification experimental device of a particle-elastic body coupled vibration system according to claim 1 is characterized in that: The hollow elastic body is a split structure.

4. The local phase state identification experimental device of a particle-elastic body coupled vibration system according to claim 3 is characterized in that: The split structure is that the hollow elastic body is formed by buckling two identical parts.

5. The local phase state identification experimental device of a particle-elastic body coupled vibration system according to claim 1, characterized in that: The wireless remote control linear motor is fixed inside the hollow elastic body through ribs.

6. The local phase state identification experimental device of a particle-elastic body coupled vibration system according to claim 1, characterized in that: The glass box is firmly connected to the workbench, and the hollow elastic body is placed in the glass box as a free boundary.

7. An experimental method for identifying the local phase state of a particle-elastic body coupled vibration system, implemented based on the experimental device for identifying the local phase state of a particle-elastic body coupled vibration system according to claim 1, characterized in that: The specific steps include: Step 1: Use DEM-FEM coupling calculation method to establish a numerical simulation model; Step 2: Get the calibration dataset: Step 3: According to the elastic body strain, effective friction coefficient μ and inertia number I extracted from each working condition and the corresponding excitation, data fitting is performed to form a relationship function or curve between excitation-elastic body strain-particle rheology, and the local phase state of the particle is detected by strain.

8. The local phase state identification experimental method of a particle-elastic body coupled vibration system according to claim 7, characterized in that: The step 2 specifically includes the following steps: Step 2.1: Under the same particle size and particle layer thickness, control the amplitude of the exciting force on the hollow elastic body, adjust the exciting frequency from small to large and from large to small, obtain the amplitude-frequency characteristic curves of the two frequency sweep paths, and extract the effective friction coefficient μ, inertia number I and elastic body strain of the granular medium during the vibration process; Step 2.2: Change the excitation force amplitude, repeat step 2.1, and perform two sets of repeated experiments; Step 2.3: Change the thickness of the particle layer and repeat steps 2.1-2.2; Step 2.4: Change the particle size and repeat steps 2.1 to 2.3; Step 2.5: Construct a calibration data set using the obtained elastic body strain, effective friction coefficient, and inertia number data.

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