A device for inverting damping performance of rubber cover layer by using hole cavity

Abstract

The application provides a device for inverting damping performance of a rubber cover layer by using a hole cavity, which comprises a hole cavity, a sample sticking plate, an accelerometer, a rubber damping layer, a probe group, a cable, a Tesla coil, a first power supply, an electrode belt, a magnetic pole belt and a second power supply; the sample sticking plate is installed on the side of the hole cavity; the accelerometer is installed on the back of the sample sticking plate; the rubber damping layer is installed on the back of the hole cavity; the probe group is located on the outer surface of the rubber damping layer; the hole cavity and the rubber damping layer are connected with one end of the Tesla coil through the cable; the other end of the Tesla coil is connected with the first power supply; the electrode belt is located on the front end of the hole cavity; the magnetic pole belt is located on the front end of the hole cavity; and the electrode belt is connected with the second power supply; the device uses heavy oil filled in the hole cavity wall plate to reduce the excitation of the coming flow to the hole cavity wall plate, uses plasma technology to suppress the tail vortex shedding effect of the hole cavity, and uses electromagnetic force to reduce the stagnation point effect of the rubber cover layer when it meets the flow, so that the signal-to-noise ratio of the damping performance test is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a device for inverting the damping performance of a rubber covering layer by using a hole cavity, belonging to the field of acoustic measurement. BACKGROUND

[0002] At present, when testing the damping performance of a rubber covering layer, an electromagnetic exciter or a broadband pulse exciter is generally used as a vibration source to excite the rubber covering layer, and an accelerometer is used to measure the vibration level difference of the rubber covering layer to evaluate the vibration suppression ability of the rubber covering layer. The corresponding standards are ASTM-E756 / Standard Test Method for Measuring the Damping Characteristics of Materials, GB / T-16406(1996) / Bending Resonance Test Method for Damping Performance of Acoustic Materials, and GB / T-18258(2000) / Test Method for Damping Performance of Damping Materials. In these standards, the resonant frequency and the half-power bandwidth of the material need to be measured to evaluate the damping performance of the material.

[0003] Since the rubber covering layer is subjected to the impact of external fluid in addition to the vibration of the main auxiliary machine and other equipment in application, when the fluid hits the rubber covering layer, the surface will undergo changes such as laminar flow-transition-turbulent flow, and the vibration characteristics generated by the turbulent vortex excitation of the rubber layer are significantly different from the vibration characteristics tested by the cantilever beam in the above standards or specifications, because the turbulent vortex excitation is a random excitation force that can only be processed by statistical averaging, and the evaluation method of vibration and noise attenuation may not be consistent with the processing method in the above standards or specifications. At the same time, since vibration attenuation may not lead to noise attenuation, it is not accurate to evaluate the damping performance of the rubber covering layer by vibration alone, and the ability of the rubber covering layer to suppress radiated noise cannot be accurately evaluated. Because vibration is a local quantity that can be achieved by relying on excitation structure alone, while noise is a propagation quantity that depends on space medium. For example, an object that vibrates in a vacuum can achieve vibration, but cannot radiate noise. Therefore, it is a key problem to be solved to evaluate the acoustic vibration performance of the rubber covering layer under turbulent excitation conditions, especially to use what kind of device to invert the damping performance of the rubber covering layer. SUMMARY

[0004] The purpose of the present application is to provide a device for inverting the damping performance of a rubber covering layer by using a hole cavity, which reduces the excitation of the cavity wall by the incoming flow by filling the cavity wall with heavy oil, suppresses the vortex shedding effect of the hole cavity by using plasma technology, and reduces the stagnation point effect of the rubber covering layer when encountering the flow by using electromagnetic force, greatly improving the signal-to-noise ratio of the damping performance test.

[0005] The purpose of the present application is achieved by comprising a hole cavity, a sample sticking plate, an accelerometer, a rubber damping layer, a probe group, a cable, a Tesla coil, a first power supply, an electrode belt, a magnetic pole belt, a second power supply, the sample sticking plate is installed on the side of the hole cavity, the accelerometer is installed on the back of the sample sticking plate, the rubber damping layer is installed behind the hole cavity, the probe group is located on the outer surface of the rubber damping layer, the hole cavity and the rubber damping layer are connected with one end of the Tesla coil through the cable, the other end of the Tesla coil is connected with the first power supply, the electrode belt is located at the front end of the hole cavity, the magnetic pole belt is located at the front end of the hole cavity, the electrode belt is connected with the second power supply, and the Tesla coil is used for transforming low voltage into high voltage.

[0006] The opening of the hole cavity is triangular, the hole cavity is composed of a first wall plate, a second wall plate, a third wall plate and a fourth wall plate, the first wall plate and the second wall plate are perpendicular to each other, the first wall plate and the third wall plate are perpendicular to each other, the second wall plate and the third wall plate are perpendicular to each other, the third wall plate and the fourth wall plate are perpendicular to each other, the first wall plate is a composite structure, the outer layer is a steel plate, the inner layer is also a steel plate, the cavity formed by the outer layer and the inner layer is filled with heavy oil, the second wall plate is a composite structure, the outer layer is a steel plate, the inner layer is also a steel plate, the cavity formed by the outer layer and the inner layer is filled with heavy oil, the third wall plate is a single-layer steel plate, and the fourth wall plate is a single-layer steel plate.

[0007] Further, the sample sticking plate is a single-layer steel plate, one side of the sample sticking plate is a smooth plane structure, and the other side of the sample sticking plate is a concave-convex structure.

[0008] Further, the accelerometer is installed on the back of the sample sticking plate through the through hole of the fourth wall plate.

[0009] Further, the rubber damping layer is installed on the outer surface of the second wall plate of the hole cavity, and the rubber damping layer is embedded with a metal mesh inside.

[0010] Further, the probe group is composed of a plurality of probes and located on the outer surface of the rubber damping layer, and the embedded part of the probe group is connected with the nodes of the metal mesh inside the rubber damping layer.

[0011] Further, the cable is a double-strand insulated cable, one end of the first strand of the cable is connected with the metal mesh of the rubber damping layer, one end of the second strand of the cable is connected with the second wall plate of the hole cavity, and the other end of the cable is connected with the Tesla coil.

[0012] Further, the first power supply is an alternating current power supply, and the second power supply is a direct current power supply.

[0013] Further, the electrode belt is made of steel and installed at the front of the fourth wall plate of the hole cavity, the magnetic pole belt is made of ferrous boron magnet and installed at the front of the fourth wall plate of the hole cavity, and the electrode belt and the magnetic pole belt are staggered and arranged, i.e. the positive electrode of the electrode belt, the N pole of the magnetic pole belt, the negative electrode of the electrode belt and the S pole of the magnetic pole belt are arranged in sequence.

[0014] Compared with the prior art, the present application has the advantages that: first, the fourth wall plate of the hole cavity is at a certain angle of attack with the incoming flow after the sample adhesive plate is installed, the turbulence generated by exciting the rubber covering layer is picked up by the accelerometer, and the vibration reduction performance of the rubber covering layer can be obtained by comparing with the standard sample (such as a steel plate). Since the vibration reduction performance data of the rubber covering layer obtained under the fluid excitation condition is an extension of the performance test of the damping material in the current national standard GB / T-18258 (2000), it makes up for the deficiency that the vibration reduction performance test of the rubber covering layer under the flow condition cannot be performed in the national standard; second, the first wall plate of the hole cavity is a composite structure, and the cavity formed between the inner and outer layers is filled with heavy oil. Since heavy oil is a material with large viscosity and large damping attenuation coefficient, it can absorb the vibration generated by the first wall plate of the hole cavity excited by the incoming flow, and reduce the influence of the vibration and radiation noise of the first wall plate of the hole cavity excited by the flow on the measurement results; third, the second wall plate of the hole cavity is a composite structure, and the cavity formed between the inner and outer layers is filled with heavy oil. Since heavy oil is a material with large viscosity and large damping attenuation coefficient, it can absorb the vibration caused by the wake vortex shedding effect generated after the hole cavity is excited by the incoming flow, and reduce the influence of the vibration and radiation noise of the second wall plate of the hole cavity caused by the wake vortex shedding on the measurement results; finally, after the rubber damping layer is attached to the outer surface of the second wall plate of the hole cavity, since it is a flexible material, when the shedding wake vortex excites the rubber damping layer after the incoming flow passes through the hole cavity, the excitation force of the shedding wake vortex is well absorbed by the flexible material, which further reduces the vibration and radiation noise generated by the incoming flow exciting the hole cavity, and improves the signal-to-noise ratio of the test.

[0015] The application has the advantages that: first, the electrode belt and the magnetic pole belt at the front end of the fourth wall plate of the hole cavity generate electromagnetic force, which has the advantages of not generating noise of any frequency, but making the incoming flow tightly adhere to the surface of the fourth wall plate, so that the incoming flow at the front end of the rubber covering layer is in a laminar flow state, and the fluid undergoes the laminar flow-transition-turbulent flow process after passing through the rubber covering layer, so that this flow state is relatively similar to the flow-induced vibration state of the rubber covering layer in practice, improving the similarity between the model test and the engineering application, and the electromagnetic force can be turned off at any time, which is very convenient; second, the probe group, the metal mesh in the rubber damping layer, and the Tesla coil form a plasma discharge device, which can supplement the energy of the shedding vortex passing through the hole cavity, and improve the temperature of the shedding vortex, reduce the viscosity of water and reduce the flow resistance, so as to further suppress the vibration and radiation noise generated by the excitation hole cavity due to the shedding vortex, and improve the signal-to-noise ratio of the test; third, the place where the sample sticking plate contacts the rubber covering layer is a concave-convex structure, which improves the ability of the rubber covering layer to adhere to the sample sticking plate, so that the rubber covering layer is not easy to be blown off by the incoming flow during the test, especially under high flow conditions, improving the test efficiency; finally, the opening of the hole cavity is triangular, and the shape of the cross section of the hole cavity is also triangular, when testing the vibration reduction performance of the rubber covering layer under different attack angle conditions, the length of the first wall plate, the second wall plate, and the third wall plate and the fourth wall plate need to be adjusted according to the set incoming flow attack angle, and after the hole cavity model is completed, it can be repeatedly used, improving the performance-price ratio of the hole cavity model manufacturing. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a schematic diagram of a device for inverting the vibration reduction performance of a rubber covering layer;

[0017] Figure 2 It is a schematic diagram of a hole cavity;

[0018] Figure 3 It is a schematic diagram of a sample sticking plate;

[0019] Figure 4 It is a schematic diagram of a first wall plate of a hole cavity;

[0020] Figure 5 It is a schematic diagram of a second wall plate of a hole cavity;

[0021] Figure 6 It is a schematic diagram of a rubber damping layer;

[0022] Figure 7 It is a schematic diagram of the fourth wall plate of the hole cavity to which the electrode belt and the magnetic pole belt are attached;

[0023] Wherein, 1 is a cavity, 2 is a sample bonding plate, 3 is an accelerometer, 4 is a rubber damping layer, 5 is a probe group, 6 is a cable, 7 is a Tesla coil, 8 is a first power supply, 9 is an electrode belt, 10 is a magnetic pole belt, 11 is a second power supply, 101 is a first wall plate, 102 is a second wall plate, 103 is a third wall plate, 104 is a fourth wall plate, 41 is a metal mesh. DETAILED DESCRIPTION

[0024] The application will be further described in detail below in combination with the drawings and specific embodiments.

[0025] The application comprises a cavity 1, a sample bonding plate 2, an accelerometer 3, a rubber damping layer 4, a probe group 5, a cable 6, a Tesla coil 7, a first power supply 8, an electrode belt 9, a magnetic pole belt 10, and a second power supply 11. The sample bonding plate 2 is installed on the side of the cavity 1, the accelerometer 3 is installed on the back of the sample bonding plate 2, the rubber damping layer 4 is installed on the back of the cavity 1, the probe group 5 is located on the outer surface of the rubber damping layer 4, the cavity 1 and the rubber damping layer 4 are connected with one end of the Tesla coil 7 through the cable 6, the other end of the Tesla coil 7 is connected with the first power supply 8, the electrode belt 9 is located at the front end of the cavity 1, the magnetic pole belt 10 is located at the front end of the cavity 1, and the electrode belt 9 is connected with the second power supply 11.

[0026] The opening of the cavity 1 of the application is triangular, and the cavity is composed of a first wall plate 101, a second wall plate 102, a third wall plate 103, and a fourth wall plate 104. The first wall plate 101 is perpendicular to the second wall plate 102, the first wall plate 101 is perpendicular to the third wall plate 103, the second wall plate 102 is perpendicular to the third wall plate 103, the third wall plate 103 is perpendicular to the fourth wall plate 104. The first wall plate 101 is a composite structure, the outer layer is a steel plate, the inner layer is also a steel plate, and the cavity composed of the outer layer and the inner layer is filled with heavy oil. The second wall plate 102 is a composite structure, the outer layer is a steel plate, the inner layer is also a steel plate, and the cavity composed of the outer layer and the inner layer is filled with heavy oil. The third wall plate 103 is a single-layer steel plate, and the fourth wall plate 104 is a single-layer steel plate. A through hole is formed in the middle part of the fourth wall plate 104.

[0027] The sample bonding plate 2 of the application is a single-layer steel plate. One side of the sample bonding plate 2 is a smooth plane structure, and the other side of the sample bonding plate 2 is a concave-convex structure, so as to facilitate the rubber covering layer to be firmly attached to the outer surface of the sample bonding plate 2.

[0028] The accelerometer 3 of the application is installed on the back of the sample bonding plate 2 through the through hole of the fourth wall plate 104. The model of the accelerometer 3 is ZC1002, and the working principle is a vibration sensor. It is passive, wide frequency response, high sensitivity, and good dynamic characteristics, and is used to obtain the vibration performance of the rubber covering layer under flow excitation conditions.

[0029] The rubber damping layer 4 of the application is installed on the outer surface of the second wall plate 102 of the hole cavity 1, the rubber damping layer 4 is embedded with the metal net 41, the rubber damping layer 4 is a white silica gel damping block made of GJ001, and the metal net 41 is embedded when the white silica gel damping block is cured, the metal net 41 is closer to one side of the rubber damping layer 4 when embedded, and each node of the metal net 41 can be seen under the sunlight.

[0030] The probe group 5 of the application is composed of multiple probes, is made of titanium alloy, is located on the outer surface of the rubber damping layer 4, and the part of the probe group 5 embedded in the rubber damping layer 4 is connected with the nodes of the metal net 41.

[0031] The cable 6 of the application is a double-stranded cable line with a copper core, and the model is BVVB2x6; the first strand of one end of the cable 6 is connected with the metal net 41 in the damping layer 4, the second strand of one end of the cable 6 is connected with the wall surface 102 of the hole cavity 1, and the other end of the cable 6 is connected with the Tesla coil 7.

[0032] The Tesla coil 7 of the application is used for voltage transformation of a power supply, a resonant transformer is used for lifting the voltage of the power supply to 5-30 kV, is used for driving the probe group 5 embedded in the rubber damping layer 4 to discharge, and is used for forming a plasma device to realize a plasma effect.

[0033] The first power supply 8 of the application is an alternating power supply, the voltage is 220 V, and the frequency is 50 Hz.

[0034] The electrode belt 9 of the application is made of stainless steel and is installed on the front of the fourth wall plate 104 of the hole cavity 1.

[0035] The magnetic pole belt 10 of the application is made of a ferrous boron magnet and is installed on the front of the fourth wall plate 104 of the hole cavity 1.

[0036] The electrode belt 9 and the magnetic pole belt 10 of the application are staggered, that is, the positive electrode of the electrode belt 9, the N pole of the magnetic pole belt 10, the negative electrode of the electrode belt 9, and the S pole of the magnetic pole belt 10 are arranged in sequence.

[0037] The second power supply 11 of the application is a direct current power supply, the model is KPS series, the brand is WANPTEK, and the direct current provided is 20 V-300 V, so as to provide current for the electrode belt 9 to realize electromagnetic force.

Claims

1. An apparatus for inverting the damping performance of a rubber cover layer using a bore cavity, characterized by: The application relates to a sample sticking plate, an acceleration meter, a rubber damping layer, a probe group, a cable, a Tesla coil, a first power supply, an electrode belt and a magnetic pole belt. The opening of the hole cavity is triangular, the hole cavity is composed of a first wall plate, a second wall plate, a third wall plate and a fourth wall plate, the first wall plate is perpendicular to the second wall plate, the first wall plate is perpendicular to the third wall plate, the second wall plate is perpendicular to the third wall plate, the third wall plate is perpendicular to the fourth wall plate, the first wall plate is a composite structure, the outer layer is a steel plate, the inner layer is also a steel plate, the cavity formed by the outer layer and the inner layer is filled with heavy oil, the second wall plate is a composite structure, the outer layer is a steel plate, the inner layer is also a steel plate, the cavity formed by the outer layer and the inner layer is filled with heavy oil, the third wall plate is a single-layer steel plate, and the fourth wall plate is a single-layer steel plate; a through hole is formed in the middle part of the fourth wall plate. The rubber damping layer is installed on the outer surface of the second wall plate of the hole cavity, and metal mesh is embedded in the rubber damping layer; the electrode belt is made of steel and is installed at the front part of the fourth wall plate of the hole cavity; the magnetic pole belt is made of a boron magnet and is installed at the front part of the fourth wall plate of the hole cavity; the electrode belt and the magnetic pole belt are staggered, that is, the positive electrode of the electrode belt, the N-pole of the magnetic pole belt, the negative electrode of the electrode belt and the S-pole of the magnetic pole belt are arranged in sequence.

2. The device for inverting the damping performance of a rubber cover layer using a hole cavity according to claim 1, characterized in that: The sample sticking plate is a single-layer steel plate, one side of the sample sticking plate is a smooth plane structure, and the other side of the sample sticking plate is a concave-convex structure.

3. The device for inverting the damping performance of a rubber cover layer using a hole cavity according to claim 1, characterized in that: The acceleration meter is installed on the back surface of the sample sticking plate through the through hole of the fourth wall plate.

4. The device for inverting the damping performance of a rubber cover layer using a hole cavity according to claim 1, characterized in that: The probe group is composed of multiple probes and is located on the outer surface of the rubber damping layer; the embedded part of the probe group is connected with the nodes of the metal mesh in the rubber damping layer.

5. The device for inverting the damping performance of a rubber cover layer using a hole cavity according to claim 1, characterized in that: The cable is a double-strand insulated cable, the first strand of the cable is connected with the metal mesh of the rubber damping layer, the second strand of the cable is connected with the second wall plate of the hole cavity, and the other end of the cable is connected with the Tesla coil.

6. The device for inverting the damping performance of a rubber cover layer using a hole cavity according to claim 1, characterized in that: The first power supply is an alternating current power supply, and the second power supply is a direct current power supply.

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