A device and method for measuring the axial acceleration sensitivity of a cylindrical hydrophone

Abstract

The application relates to a kind of axial acceleration sensitivity measuring device and measuring method of circular pipe hydrophone, including base, harf, end cover, to be measured circular pipe hydrophone, top cover, preamplifier, accelerometer and exciter;Wherein, base includes bottom disc and the semicircular pipe of being protruded in the center of bottom disc, a plurality of mounting holes of different sizes are formed in bottom disc, to cooperate with the exciter of different interfaces for installation;Semicircular pipe top is provided with a lead slot;Harf is semicircular pipe structure and its pipe diameter is adapted to the semicircular pipe in the center of bottom disc, multiple screw holes are arranged in the middle of inner wall of harf along the height direction interval.This application can be compared to show the axial acceleration response of circular pipe hydrophone by reasonable structure design and the structure integrated design of preamplifier circuit of first hydrophone, and provides important basis for performance evaluation and application of circular pipe hydrophone.

Description

Technical fields:

[0001] This invention belongs to the field of hydrophone testing technology, and relates to a device and method for measuring the axial acceleration sensitivity of a circular tube hydrophone. Background technology:

[0002] Circular tube hydrophones are ideal for towed linear array systems due to their high sensitivity and wide bandwidth response. However, during acoustic detection, they are affected by axial and radial vibration signals. Therefore, acceleration sensitivity, as one of the important performance indicators of circular tube hydrophones, reflects the hydrophone's response characteristics under acceleration. Measuring the acceleration sensitivity of a hydrophone is therefore crucial for evaluating its performance in water.

[0003] Currently, testing cylindrical hydrophones of different sizes requires changing multiple sets of fixtures, making the process complex. Furthermore, the preamplifier circuit of the hydrophone is typically located on the outside during testing, resulting in relatively poor electromagnetic shielding. Additionally, existing testing methods are often only applicable to cylindrical hydrophones of a single size, and changing different fixtures during comparative hydrophone performance testing is inefficient and inconsistent. Summary of the Invention:

[0004] The technical problem to be solved by the present invention is to provide a device and method for measuring the axial acceleration sensitivity of a circular tube hydrophone. Through a reasonable structural design and an integrated design of the first-stage hydrophone and the preamplifier circuit, the axial acceleration response of the circular tube hydrophone can be compared and characterized, providing an important basis for the performance evaluation and application of the circular tube hydrophone.

[0005] The technical solution of this invention is to provide an axial acceleration sensitivity measuring device for a circular tube hydrophone, comprising a base, a ferrule, an end cap, a circular tube hydrophone to be tested, a top cap, a preamplifier, an accelerometer, and a vibrator; wherein,

[0006] The base includes a chassis and a semi-circular tube protruding from the center of the chassis. The chassis has several mounting holes of different sizes to accommodate vibrators with different interfaces. A lead wire groove is opened at the top of the semi-circular tube.

[0007] The Hafu has a semi-circular tube structure and its diameter is adapted to the semi-circular tube in the center of the chassis. Multiple threaded holes are spaced along the height direction in the middle of the inner wall of the Hafu.

[0008] The diameter of the end cap is adapted to the outer diameter of the semi-circular tube, and the end cap is installed on the top of the semi-circular tube by fasteners.

[0009] The test tube hydrophone is integrally cast and fixed inside the tube formed by the semi-circular tube and the ferrule.

[0010] The top cover is a cylinder with an outer diameter smaller than the inner diameter of the Huff. There are two top covers, which are installed at the upper and lower ends of the hydrophone under test. The end of the top cover facing the hydrophone under test has a recessed hole with the same size as the outer diameter of the hydrophone under test. The end of the hydrophone under test is located in the recessed hole and is interference-fitted with the top cover. The top of the top cover at the upper end also has a lead wire hole. The lead wire of the hydrophone under test passes through the lead wire hole and is connected to the input terminal of the preamplifier.

[0011] The preamplifier is externally encapsulated in a metal shell, and internally contains the preamplifier circuit. The preamplifier is placed above the hydrophone under test and fixed inside the circular tube formed by the semi-circular tube and the Hafu. The wires led out from the output end of the preamplifier are clamped by the end cap.

[0012] The vibrator is installed on the corresponding chassis mounting holes;

[0013] The accelerometer is connected to the exciter to ensure that the hydrophone under test and the accelerometer maintain the same amplitude during vibration;

[0014] Both the base and the hood are made of metal.

[0015] Based on the accelerometer method, this invention, through reasonable structural design, can be adapted to hydrophones of different sizes. The preamplifier is placed inside a metal cavity, ensuring that the acceleration response signal output process is all inside the shielding layer. The structure is simple and the test is stable, which can effectively avoid the design defects existing in the existing solutions.

[0016] Preferably, the semi-circular tube and the ferrule are joined together to form a circular tube and then fastened with screws.

[0017] Preferably, a protrusion with an inner diameter of 11.8 mm and an angle of 120° extends from the middle of the inner wall of the semi-circular tube. This avoids direct contact and contact between the internal hydrophone to be tested and its inner wall.

[0018] As a preferred option, the installation position is selected according to the length of the cylindrical hydrophone to be tested. Long screws are used to pass through the corresponding screw holes on the side wall of the Huff to tighten the top cover, so that the Huff as a whole is separated from the cylindrical hydrophone to be tested. The remaining screw holes that are not filled with long screws are sealed with screws.

[0019] Preferably, the base, hub, end cap, and top cap are made of aluminum alloy.

[0020] Preferably, the preamplifier circuit operates in the frequency range of 10Hz to 10kHz, outputs in a differential form, and has an amplification of 40dB.

[0021] As a preferred option, the accelerometer 7 has a sensitivity of 100 mv / g.

[0022] Preferably, when using the accelerometer, one side is connected to the accelerometer power supply, and the analog signal is connected to the oscilloscope.

[0023] This invention also provides a measurement method for the axial acceleration sensitivity measuring device of a circular tube hydrophone as described above. The accelerometer and chassis of the measuring device are fixed on the surface of a rigid vibration table. The accelerometer measures the axial vibration acceleration experienced by the circular tube hydrophone under test. A low-voltage power supply and an accelerometer power supply are respectively supplied to the circular tube hydrophone under test and the accelerometer. The vibration table maintains vertical vibration. A sinusoidal signal of a specific frequency is emitted by a signal source and amplified by a power amplifier before being transmitted to the vibration table. The circular tube hydrophone under test then converts the acquired sound pressure information into an electrical signal, which is input to a preamplifier and filter for further processing. The peak-to-peak voltage U of the processed circular tube hydrophone and the accelerometer is then compared. H with U a The open-circuit voltage at the output terminal is displayed on the oscilloscope; finally, the axial acceleration sensitivity M of the hydrophone under test can be obtained according to equation (1). a :

[0024]

[0025] In the formula, M ar This refers to the sensitivity of a standard accelerometer.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] This invention proposes a method for measuring the axial acceleration sensitivity of a circular tube hydrophone. The method employs an accelerometer to measure acceleration sensitivity. Under simulated acceleration conditions, the hydrophone under test and the preamplifier circuit are placed in the same electromagnetically shielded environment. The circular tube hydrophone under test is rigidly connected to the test platform to ensure no extraneous signal interference or vibration loss. This device is adaptable to circular tube hydrophones of different sizes, and the testing process is fast, accurate, and stable. Attached image description:

[0028] Figure 1 This is a partial structural diagram of the present invention;

[0029] Figure 2 This is a schematic diagram of the device of the present invention in use;

[0030] Figure 3 This is a schematic diagram illustrating the measurement principle of the present invention. Detailed implementation method:

[0031] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0032] The axial acceleration sensitivity measuring device of the present invention mainly includes a base 1, a humb 2, an end cap 3, a hydrophone for the test tube 4, a top cover 5, a preamplifier 6, an accelerometer 7, and a vibrator 8.

[0033] like Figure 1 , 2 In this embodiment, the base 1 is made of aluminum alloy. The base includes a bottom chassis, which is a cylinder with a diameter of φ64mm and a thickness of 10mm. Circular mounting holes of φ4.5mm and φ9.5mm are opened at positions φ40mm and φ50mm respectively to accommodate exciters 8 with different interfaces. A semi-circular tube with an outer diameter of φ28mm and an inner diameter of φ14mm, raised 120mm from the center of the chassis, has a lead-in groove at the top and two M4 threaded holes on both sides. The wires leading from the output of the preamplifier 6 are clamped by the end cap 3. A 11.8mm inner diameter, 120° protrusion extends from the middle of the inner wall of the semi-circular tube. The hydrophone 4 to be tested and the preamplifier 6 are positioned vertically and placed inside the semi-circular tube of the base 1, and then fixed to the semi-circular tube and the preamplifier 2 by screws on the auger 2. Six M4 threaded holes are opened on the side of the semi-circular tube, which are tightened to the auger 2 with screws during installation. During installation and use, the axial direction of the test tube hydrophone 4 should be aligned with the vibration direction of the exciter 8.

[0034] In this embodiment, the Hafu 2 is made of aluminum alloy. It has a semi-circular tubular structure with an outer diameter of φ28mm, an inner diameter of φ14mm, and a height of 85mm, allowing it to be joined with the semi-circular tube to form a circular tube. Twelve M3 threaded holes are located in the middle of the inner wall of the Hafu 2. The installation position is selected according to the length of the hydrophone. The top cover 5 is tightened using long M3 screws, ensuring that the Hafu 2 does not contact the hydrophone under test. The remaining holes are sealed with short M3 screws when not in use. Six φ4.5mm through holes are opened on the side for tightening with the base 1.

[0035] In this embodiment, the end cap 3 is made of aluminum alloy. The end cap has a diameter of φ28mm and a height of 4mm. Two through holes with a diameter of φ4.5mm are opened on the surface to clamp the signal line of the hydrophone 4 under test to the base 1 with screws.

[0036] In this embodiment, the hydrophone under test 4 is integrally molded. During use, it is rigidly connected to the cavity formed by the semi-circular tube and the ferrule 2. Both the base 1 and the ferrule 2 are made of metal, thus creating an internal shielded environment to prevent the introduction of external interference. There are two pins on the upper surface of the component, representing the positive and negative signals of the hydrophone under test, which are connected to the input terminal of the preamplifier 6.

[0037] In this embodiment, the top cover 5 is made of aluminum alloy. It is a cylindrical shape with an outer diameter of φ11.8mm. There are two top covers 5, installed at the upper and lower ends of the hydrophone 4 under test. The end of the top cover 5 facing the hydrophone 4 has a recessed countersunk hole of the same size as the outer diameter of the hydrophone 4. The end of the hydrophone 4 under test is located in the countersunk hole and is press-fitted with the top cover 5. The top cover 5 is fixed at both ends of the hydrophone to avoid the sensing part of the hydrophone 4, and a lead hole is provided for connecting the preamplifier 6. The inner diameter of the countersunk hole can be adapted to different hydrophone sizes.

[0038] In this embodiment, the preamplifier 6 is externally encapsulated in a metal shell, and internally contains the preamplifier circuit, which is connected via pin leads. The preamplifier circuit operates in the frequency range of 10Hz to 10kHz, outputs differentially, and has an amplification of 40dB.

[0039] In this embodiment, the sensitivity of the accelerometer 7 is 100 mV / g. The accelerometer 7 is rigidly connected to the exciter 8 to ensure that the hydrophone 4 under test and the accelerometer 7 maintain the same amplitude during vibration. In use, one side is connected to the accelerometer power supply, and the analog signal is connected to the oscilloscope.

[0040] The measurement principle diagram used in this invention is as follows: Figure 3 The measurement system includes a signal source, power amplifier, device under test (DUT), accelerometer, exciter, filter, oscilloscope, accelerometer power supply, and low-voltage power supply for the hydrophone. The accelerometer and the DUT are fixed together on a rigid vibration table (exciter). The accelerometer measures the axial vibration acceleration experienced by the DUT. During measurement, the low-voltage power supply and accelerometer power supply respectively power the DUT and the accelerometer. The vibration table vibrates vertically. A sinusoidal signal of a specific frequency is emitted by the signal source, amplified by the power amplifier, and transmitted to the vibration table. The DUT then converts the acquired sound pressure information into an electrical signal, which is input to a preamplifier and filter for further processing. Finally, the peak-to-peak voltage U0 of the DUT and the accelerometer is compared. H with U a The open-circuit voltage at the output terminal is displayed on the oscilloscope. Finally, the axial acceleration sensitivity M of the test tube hydrophone can be obtained according to equation (1). a :

[0041]

[0042] In the formula, M ar This refers to the sensitivity of a standard accelerometer.

[0043] The above testing scheme can also employ laser vibration measurement, where a laser beam from a laser probe is focused onto a surface along the direction of the hydrophone's vibration. The reflected laser beam returns to the laser probe, and the vibration acceleration of the hydrophone is directly measured by the laser vibration meter decoder. Then, based on the open-circuit voltage U output by the hydrophone... H The acceleration sensitivity M of the hydrophone under test can then be obtained. a .

[0044] The mounting structure of this invention incorporates a fixed top cover to accommodate cylindrical hydrophones of different sizes, and the metal end caps are rigidly connected to the hydrophone and vibration platform to ensure lossless vibration transmission. The preamplifier circuit is also placed within an electromagnetically shielded environment to prevent the introduction of unwanted interference. This allows for precise comparison of the axial acceleration response of the cylindrical hydrophone at different frequencies, and the test results provide data for hydrophone performance evaluation.

[0045] The above description only illustrates preferred embodiments of the present invention and should not be construed as limiting the scope of the claims. Any equivalent procedural modifications made using this specification are included within the patent protection scope of this invention.

Claims

1. A device for measuring the axial acceleration sensitivity of a circular tube hydrophone, characterized in that: Includes a base, a humping chamber, end caps, a hydrophone under test (tube), a top cover, a preamplifier, an accelerometer, and an exciter; among which, The base includes a chassis and a semi-circular tube protruding from the center of the chassis. The chassis has several mounting holes of different sizes to accommodate vibrators with different interfaces. A lead wire groove is opened at the top of the semi-circular tube. The Hafu has a semi-circular tube structure and its diameter is adapted to the semi-circular tube in the center of the chassis. Multiple threaded holes are spaced along the height direction in the middle of the inner wall of the Hafu. The diameter of the end cap is adapted to the outer diameter of the semi-circular tube, and the end cap is installed on the top of the semi-circular tube by fasteners. The test tube hydrophone is integrally cast and fixed inside the tube formed by the semi-circular tube and the ferrule. The top cover is a cylinder with an outer diameter smaller than the inner diameter of the Huff. There are two top covers, which are installed at the upper and lower ends of the hydrophone under test. The end of the top cover facing the hydrophone under test has a recessed hole with the same size as the outer diameter of the hydrophone under test. The end of the hydrophone under test is located in the recessed hole and is press-fitted with the top cover. The top of the top cover at the upper end also has a lead wire hole. The lead wire of the hydrophone under test passes through the lead wire hole and is connected to the input terminal of the preamplifier. The preamplifier is externally encapsulated in a metal shell, and internally contains the preamplifier circuit. The preamplifier is placed above the hydrophone under test and fixed inside the circular tube formed by the semi-circular tube and the Hafu. The wires led out from the output end of the preamplifier are clamped by the end cap. The vibrator is installed on the corresponding chassis mounting holes; The accelerometer is connected to the exciter to ensure that the hydrophone under test and the accelerometer maintain the same amplitude during vibration; Both the base and the hood are made of metal.

2. The axial acceleration sensitivity measuring device for a circular tube hydrophone according to claim 1, characterized in that: The semi-circular tube and the ferrule are joined together to form a circular tube, which is then secured with screws.

3. The axial acceleration sensitivity measuring device for a circular tube hydrophone according to claim 2, characterized in that: A protrusion with an inner diameter of 11.8 mm and an angle of 120° extends from the middle of the inner wall of the semi-circular tube.

4. The axial acceleration sensitivity measuring device for a circular tube hydrophone according to claim 1, characterized in that: Select the installation position according to the length of the cylindrical hydrophone to be tested, and use a long screw to pass through the corresponding screw hole on the side wall of the HFU to tighten the top cover, so that the HFU as a whole is separated from the cylindrical hydrophone to be tested. Seal the remaining screw holes that are not filled with long screws with screws.

5. The axial acceleration sensitivity measuring device for a circular tube hydrophone according to claim 1, characterized in that: The base, hub, end caps, and top cap are made of aluminum alloy.

6. The axial acceleration sensitivity measuring device for a circular tube hydrophone according to claim 1, characterized in that: The preamplifier circuit operates in the frequency range of 10Hz to 10kHz, outputs differentially, and has an amplification of 40dB.

7. The axial acceleration sensitivity measuring device for a circular tube hydrophone according to claim 1, characterized in that: The sensitivity of the accelerometer (7) is 100 mv / g.

8. The axial acceleration sensitivity measuring device for a circular tube hydrophone according to claim 7, characterized in that: When using the accelerometer, connect one side to the accelerometer power supply and connect the analog signal to the oscilloscope.

9. The measurement method of the axial acceleration sensitivity measuring device for a circular tube hydrophone as described in any one of claims 1-8, characterized in that: The accelerometer and chassis of the measuring device are fixed on the platform of a rigid vibration table. The accelerometer measures the axial vibration acceleration experienced by the test circular tube hydrophone. Power is supplied to the test circular tube hydrophone and the accelerometer via a low-voltage power supply and an accelerometer power supply, respectively. The vibration table vibrates vertically. A sinusoidal signal of a specific frequency is emitted by a signal source, amplified by a power amplifier, and then transmitted to the vibration table. The test circular tube hydrophone then converts the acquired sound pressure information into an electrical signal, which is input to a preamplifier and filter for further processing. The peak-to-peak voltage U of the processed test circular tube hydrophone and the accelerometer is then compared. H with U a The open-circuit voltage at the output terminal is displayed on the oscilloscope; finally, the axial acceleration sensitivity M of the hydrophone under test can be obtained according to equation (1). a : In the formula, M ar This refers to the sensitivity of a standard accelerometer.

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