Non-contact small-caliber corrugated pipe modal characteristic testing device

Abstract

The invention relates to the technical field of non-contact small-caliber corrugated pipe modal characteristic testing, in particular to a non-contact small-caliber corrugated pipe modal characteristic testing device. According to the device, force hammer excitation is applied to the small-caliber corrugated pipe to be detected, part of external sound field noise interference is effectively isolated through the wedge type silencing box, response data are synchronously collected through the multiple sound pressure sensors, and modal characteristic parameters of the small-caliber corrugated pipe can be accurately obtained after calculation and analysis. Measurement deviation caused by additional rigidity and mass of a traditional vibration exciter and a traditional contact sensor is overcome, testing precision and reliability are remarkably improved, installation difficulty and complexity of the traditional contact sensor on the small-caliber corrugated pipe are avoided, and an effective means is provided for scientific prediction of modal characteristics of the small-caliber corrugated pipe.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-contact corrugated pipe modal characteristic test, in particular to a non-contact corrugated pipe modal characteristic test device. BACKGROUND

[0002] Small-diameter corrugated pipes, as a typical periodic thin-walled flexible structure, are widely used in aviation, aerospace, and instrument and metering systems. The modal characteristics of the small-diameter corrugated pipes are directly related to the structural stability and fatigue life during service. However, due to the extremely thin wall thickness and complex geometry of the small-diameter corrugated pipes, the traditional modal test method has obvious deficiencies in application. The additional mass and stiffness of the exciter and the contact sensor can significantly change the structural dynamics characteristics. It is difficult and cumbersome to install the contact sensor on some small-diameter corrugated pipes, and in extreme cases, it is even impossible to arrange the contact sensor. Although the non-contact laser vibration meter can avoid the mass addition effect, the equipment cost is high, and the installation and preparation process of the test is also very complex. Therefore, a corrugated pipe modal test method based on the principle of acoustic vibration reciprocity is proposed, and its applicability and engineering value are systematically evaluated.

[0003] The existing test method cannot accurately obtain the modal characteristics of the small-diameter corrugated pipe, therefore, in view of the deficiencies in the prior art, it is very necessary to provide a non-contact small-diameter corrugated pipe modal characteristic test device to solve the deficiencies in the prior art.

[0004] At present, the modal test of the corrugated pipe is mostly carried out using the contact sensor, without considering the influence of the additional mass and stiffness of the contact sensor on the modal characteristics of the corrugated pipe, and in some cases with small wave distance and straight edge, the contact sensor cannot be arranged.

[0005] The corrugated pipe structure has high symmetry. Even if the contact sensor can be effectively arranged by the traditional force hammer-contact sensor system, the contact sensor cannot capture the double root modal parameters of the corrugated pipe, because the additional mass of the contact sensor also changes the symmetry of the structure, and further destroys the double root modal parameters of the symmetrical structure, especially in the measurement of the double root modal parameters of the small-diameter corrugated pipe.

[0006] The existing test method cannot accurately obtain the double root modal parameters of the small-diameter corrugated pipe, and cannot avoid the cumbersome installation and preparation process of the contact sensor.

[0007] Therefore, in view of the deficiencies in the prior art, it is very necessary to provide a non-contact small-diameter corrugated pipe modal characteristic test device to solve the deficiencies in the prior art. SUMMARY

[0008] The present application aims to avoid the shortcomings of the prior art and provides a non-contact small-diameter corrugated pipe modal characteristic test device, which tests the small-diameter corrugated pipe through hammer excitation, measures the response data of the sound pressure sensor in the wedge-shaped sound absorbing box, and can accurately obtain the modal characteristic parameters of the small-diameter corrugated pipe to be tested after calculation, can avoid the influence of the additional mass and stiffness of the exciter and the contact sensor on the measurement accuracy, has higher test accuracy, and compared with the laser vibration tester which is also non-contact, not only reduces the cost, but also the installation and preparation process of the test is very efficient.

[0009] The above-mentioned object of the present application is achieved by the following technical means.

[0010] The present application provides a non-contact small-diameter corrugated pipe modal characteristic test device, which comprises a hammer, a sound pressure sensor and a fixed flat base, four lifting cylinders are installed at the corners of the upper surface of the fixed flat base, an axial positioning plate is installed on the four lifting cylinders, an axial actuator is fixedly installed on the axial positioning plate, an upper flange plate is fixedly installed at the output end of the axial actuator, a fixed platform is installed on the fixed flat base, a connecting rod is installed on the fixed platform, a lower flange plate is fixedly installed at the top end of the connecting rod, and a corrugated pipe body is flange-mounted between the upper flange plate and the lower flange plate.

[0011] A wedge-shaped sound absorbing box is installed on the fixed base, a movable sealing door is hingedly installed on the side of the wedge-shaped sound absorbing box, cut-in grooves are formed at the top and bottom of the wedge-shaped sound absorbing box and matched with the output end of the axial actuator, the cut-in grooves extend from the movable sealing door to the central part of the wedge-shaped sound absorbing box, sound insulation positioning grooves are arranged at the top and bottom of the movable sealing door, sound insulation cover plates are bolted in the sound insulation positioning grooves, and the sound insulation cover plates movably cover the outside of the cut-in grooves.

[0012] Specifically, an air pipe and a water pipe are movably installed at the bottom of the lower flange plate, an air pump is installed on the air pipe, a water pump is installed on the water pipe, the air pipe is connected to external ventilation equipment through the air pump, the water pipe is connected to an external water tank through the water pump, and the air pipe and the water pipe movably pass through the bottom of the wedge-shaped sound absorbing box.

[0013] Specifically, a hammer force sensor is installed in the hammer, a sound pressure sensor is arranged near the corrugated pipe body, the sound pressure sensor and the hammer force sensor are electrically connected to a signal acquisition instrument, and the signal acquisition instrument is electrically connected to a computer.

[0014] The present application tests the small-diameter corrugated pipe through hammer excitation, measures the sound pressure response parameters of the sound pressure sensors at both ends of the small-diameter corrugated pipe, and can accurately obtain the modal characteristics of the corrugated pipe after calculation, has higher test accuracy, can avoid the influence of the additional mass and stiffness of the exciter and the contact sensor on the measurement accuracy, and can more accurately obtain the vibration isolation performance parameters of the corrugated pipe. BRIEF DESCRIPTION OF DRAWINGS

[0015] The application is further described with the drawings, but the content in the drawings does not constitute any limitation to the application.

[0016] Figure 1 is a perspective structural schematic diagram of a non-contact small-bore corrugated pipe modal characteristic test device of the application Figure 1 .

[0017] Figure 2 is an internal structural schematic diagram of a wedge-shaped sound-absorbing box of a non-contact small-bore corrugated pipe modal characteristic test device of the application.

[0018] Figure 3 is a side view sectional view of a non-contact small-bore corrugated pipe modal characteristic test device of the application.

[0019] Figure 4 is a connection schematic diagram of a signal acquisition instrument, a computer, a hammer force sensor and a sound pressure sensor of a non-contact small-bore corrugated pipe modal characteristic test device of the application.

[0020] Figure 5 is a perspective structural schematic diagram of a wedge-shaped sound-absorbing box of a non-contact small-bore corrugated pipe modal characteristic test device of the application.

[0021] Figure 6 is a principle schematic diagram of partial power conversion of a volume sound source of a non-contact small-bore corrugated pipe modal characteristic test device of the application into structure vibration.

[0022] From the Figures 1 to 5 , comprising:

[0023] 1. a corrugated pipe body;

[0024] 2. a force hammer;

[0025] 3. a sound pressure sensor;

[0026] 4. a signal acquisition instrument;

[0027] 5. a computer;

[0028] 6. a positioning support device;

[0029] 7. a lower flange plate;

[0030] 8. a fixed base;

[0031] 9. an adjusting connecting rod;

[0032] 10. an air pipe;

[0033] 11. an air pump;

[0034] 12. Wedge-shaped silencer box;

[0035] 13. Axial positioning plate;

[0036] 14. Axial actuator;

[0037] 15. Axial force sensor;

[0038] 16. Movable sealed door;

[0039] 17. Axial servo valve;

[0040] 18. Columns;

[0041] 19. Upper flange;

[0042] 20. Lifting cylinder;

[0043] 21. Sound-absorbing wedge;

[0044] 22. Water pump;

[0045] 23. Water pipes;

[0046] 24. Movable hinge plate;

[0047] 25. Fix the flat base;

[0048] 26. Signal acquisition instrument;

[0049] 27. Computer;

[0050] 28. Lifting block;

[0051] 29. Axial force sensor;

[0052] 30. Axial servo valve;

[0053] 31. Observation slot

[0054] 32. Soundproof cover

[0055] 33. Cut-in groove Detailed Implementation

[0056] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the present invention will be further described below with reference to the following embodiments. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0057] like Figures 1-6As shown, a non-contact small-bore corrugated pipe modal characteristic test device includes a force hammer 2, a fixed flat base 25, a positioning support 6 beside the fixed flat base 25, the positioning support 6 extending above the fixed flat base 25, a fixed base 8 installed on the fixed flat base 25, four lifting oil cylinders 20 installed at the four corners of the upper surface of the fixed flat base 25, an axial positioning plate 13 installed on the four lifting oil cylinders 20, an axial actuator 14 fixedly installed on the axial positioning plate 13, an upper flange plate 19 fixedly installed at the output end of the axial actuator 14, a fixed base 8 installed on the fixed flat base 25, an adjusting connecting rod 9 installed on the fixed base 8, a lower flange plate 7 fixedly installed at the top end of the adjusting connecting rod 9, a corrugated pipe body 1 flange-mounted between the upper flange plate 19 and the lower flange plate 7, and the bottom of the adjusting connecting rod 9 connected to the fixed base 8.

[0058] 34. The positioning support 6 is slidably installed with a sharp split type muffler box 12, the movable sealing door 16 is hingedly installed on the side of the sharp split type muffler box 12, the top and bottom of the sharp split type muffler box 12 are provided with cut-in grooves 33 which are movably matched with the output end of the axial actuator 14 and the adjusting connecting rod 9, the cut-in grooves 33 extend from the movable sealing door 16 to the central part of the sharp split type muffler box 12, the top and bottom of the sharp split type muffler box 12 are provided with cut-in grooves 33, the movable sealing door 16 is connected with the sharp split type muffler box 12, and the movable sealing door 16 is connected with the sharp split type muffler box 12.

[0059] The moving direction of the sharp split type muffler box 12 is vertical, and the corrugated pipe body 1 moves and outputs at two sides, respectively, the output of the lifting oil cylinder 5 can adjust the height of the axial positioning plate 6 and then roughly adjust the height of the axial actuator 14, and then the axial actuator 14 is started according to the length and other parameters of the corrugated pipe to realize precise adjustment of the displacement of the axial upper flange plate 19, the lower flange plate 7 is fixed through the adjusting connecting rod 9 and the fixed base 8, and then the corrugated pipe body 1 is positioned.

[0060] The bottom of the lower flange plate 7 is movably installed with an air pipe 10 and a water pipe 23, the air pump 11 is installed on the air pipe 10, the water pump 25 is installed on the water pipe 23, the air pipe 10 is connected to the external ventilation equipment through the air pump 11, the water pipe 23 is connected to the external water tank through the water pump 25, and the air pipe 10 and the water pipe 23 movably pass through the bottom of the sharp split type muffler box 12.

[0061] The bottom of the lower flange plate 7 can realize the working condition of the corrugated pipe body 1 under the air pressure or water pressure state through the air pipe 10 and the water pipe 23, and the gas or water can be introduced into the inside of the corrugated pipe body 1, and the air pipe 10 and the water pipe 23 also movably pass through the sharp split type muffler box 12.

[0062] The hammer 2 is internally provided with a hammer force sensor, the corrugated pipe body 1 is provided with a sound pressure sensor 3 near both ends of the upper flange plate 19 and the lower flange plate 7, the sound pressure sensor 3 and the hammer force sensor are electrically connected to a signal acquisition instrument 4, and the signal acquisition instrument 4 is electrically connected to a computer 5.

[0063] In the specific test, the force hammer 2 is used for excitation, the force hammer 2 is of a model of PCB086C04, a measurement range is 250KN, a sensitivity is 2.34Pc / N, the sound pressure sensor 3 is of a range of 10e4 m / s2, a charge amplifier is of a model of GSTYE5852B, voltage / IEPE input, impedance is greater than 100Ω, noise is less than 5μV, accuracy is ±1%, and the signal acquisition instrument 4 is a multi-channel signal acquisition instrument 4 (Synergy16V) with 24 channels, each having an independent 64-bit analog-to-digital converter, a bandwidth of 25MHz, and a model analysis software of LMS Test.Lab, which can perform control and various data analysis functions required. The sound pressure response of the corrugated pipe body 1 is obtained through the sound pressure sensor 3, the modal characteristic parameters can be obtained in the LMS Test.Lab, and precise tests can be performed in combination with a modal purification algorithm.

[0064] The axial actuator 14 is of an Instron8874, an axial load capacity is +25kN, and an actuator stroke is 100mm.

[0065] The sound pressure sensor 3 is of a range of 10e4 m / s2, a charge amplifier is of a model of

[0066] GSTYE5852B, voltage / IEPE input, impedance is greater than 100Ω, noise is less than 5μV, and accuracy is ±1%.

[0067] The air pump 11 is of a power of 3W-2.4 / 40, an air inlet pressure is 0.1034mpa (standard atmospheric pressure), and an exhaust volume is 2.4m 3 / min.

[0068] The non-contact small-diameter corrugated pipe modal characteristic test device provided in the embodiment is based on the sound-vibration reciprocity principle, a plurality of sound pressure sensors 3 are used as response sensors for non-contact measurement, there is no additional mass influence, modal frequencies, dampings and vibration modes of the small-diameter corrugated pipe can be obtained, and meanwhile, the small-diameter corrugated pipe is not damaged. The sound pressure sensor 3 can replace a sound pressure sensor array.

[0069] The present application can obtain the modal characteristic parameters through the force hammer 2 exciting the test small caliber corrugated pipe, the sound pressure response parameters of the sound pressure sensor 3 at both ends of the corrugated pipe, and the LMS Test.Lab, the precision of the test is higher, the influence of the additional mass and the stiffness of the contact type sensor on the measurement precision can be avoided, the isolation performance parameters of the corrugated pipe can be quickly and accurately obtained, and the cumbersome fixing and on-site wiring work of the contact type sensor during the modal test is solved.

[0070] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A non-contact modal characteristic testing device for small-diameter corrugated pipes, characterized in that: The device includes a hammer and a fixed flat base. The fixed flat base is further equipped with a positioning support and a fixed base. The fixed base extends above the fixed flat base. Lifting cylinders are installed at the four corners of the upper surface of the fixed flat base. An axial positioning plate is installed on each of the four lifting cylinders. An axial actuator is fixedly installed on the axial positioning plate. An upper flange is fixedly installed at the output end of the axial actuator. The positioning support is also installed on the fixed flat base. A connecting rod is installed on the fixed base. A lower flange is fixedly installed on the connecting rod. A bellows body is installed between the upper flange and the lower flange. A wedge-shaped silencer is fixedly installed on the positioning support. A movable sealing door is hinged to the side of the wedge-shaped silencer. The top and bottom of the wedge-shaped silencer are provided with cutting grooves that movably cooperate with the output end of the axial actuator and the connecting rod. The cutting grooves extend from the movable sealing door to the center of the wedge-shaped silencer. The movable sealing door is provided with a soundproof cover plate, which can cover the same horizontal axis as the cutting groove.

2. The non-contact small-diameter corrugated pipe modal characteristic testing device according to claim 1, characterized in that: The hammer is equipped with a hammer force sensor inside, and sound pressure sensors are installed at both ends of the bellows body near the upper and lower flanges. The sound pressure sensors and the hammer force sensors are electrically connected to a signal acquisition device, which is electrically connected to a computer.

3. The non-contact small-diameter corrugated pipe modal characteristic testing device according to claim 2, characterized in that: An air pipe and a water pipe are movably installed at the bottom of the lower flange. An air pump is installed on the air pipe, and a water pump is installed on the water pipe. The air pipe is connected to an external ventilation device through the air pump, and the water pipe is connected to an external water tank through the water pump. The air pipe and the water pipe movably pass through the bottom of the wedge-shaped silencer box.

4. The non-contact small-diameter corrugated pipe modal characteristic testing device according to claim 4, characterized in that: The internal sound-absorbing body of the wedge-shaped silencer has a wedge-shaped structure, and the sound-absorbing wedge adopts a gradually changing wedge shape.

5. The non-contact small-diameter corrugated pipe modal characteristic testing device according to claim 4, characterized in that: An axial force sensor and an axial servo valve are installed on the axial actuator, and a radial force sensor and a radial servo valve are installed on the radial actuator.

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