Variable-curvature shell broadband V-shaped flextensional transducer, method for radiating sound waves in water and Cymbal array

Abstract

The invention relates to the technical field of underwater acoustic transducers, in particular to a variable curvature shell broadband V-shaped flextensional transducer, a method for radiating sound waves in water and a Cymbal array, comprising: an upper shell 1 comprising a protruding portion 11, a recessed portion 12, a pre-tightening portion 13 and a fixing portion 14, the protruding portion 11 providing a positive curvature radiating surface and having a convex surface extending from the inside of the shell to the outside of the shell, the recessed portion 12 being provided with a convex surface extending from the inside of the shell to the outside of the shell, and the pre-tightening portion 13 being provided with a convex surface extending from the inside of the shell to the outside of the shell; the concave part 12 provides a negative curvature radiation surface, is in transition connection between the convex part 11 and the pre-tightening part 13 and is provided with an arc-shaped section, the arc-shaped circle center is located outside the shell, the fixed part 14 comprises a plurality of parts extending outwards in different radial directions of the pre-tightening part 13, and the parts are arranged in the circumferential direction of the pre-tightening part 13 and connected with the pre-tightening part 13; the structure of the lower shell 2 and the upper shell 1 are in mirror symmetry along the horizontal plane; the pre-tightening part 13 of the lower shell 2 and the pre-tightening part 13 of the upper shell 1 abut against each other and are detachably connected. And the vibrator is arranged in the upper shell 1 and the lower shell 2 and is fixedly connected with the upper shell 1 and the lower shell 2.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater acoustic transducers, and particularly to a broadband V-type flextensional transducer with a variable curvature shell, a method for radiating acoustic waves in water, and a Cymbal array. Background Art

[0002] As a typical flextensional transducer, the traditional V-type flextensional transducer has the characteristics of low frequency and high power, and is widely used in underwater sound sources or small platforms such as UUVs. However, due to its large mechanical Q value, the peak of its response curve is relatively sharp and the bandwidth is narrow, so it can only transmit single-frequency signals. If a higher transmission response and non-distorted signal waveform are required in underwater signal transmission, broadband signals need to be transmitted. Therefore, how to achieve broadband transmission is the main optimization direction of the V-type flextensional transducer.

[0003] The Cymbal transducer is a typical small-size flextensional transducer after the light-weighting and miniaturization of the V-type transducer. By arranging it in a dense array, good directivity or receiving performance can be achieved. However, because its vibration form is similar to that of the traditional V-type flextensional transducer, the problem of narrow bandwidth has still not been well solved.

[0004] The main vibration mode of the traditional V-type flextensional / Cymbal transducer is that the vibration of the internal oscillator drives the bending vibration of the external shell. Its narrowband characteristic causes the transducer to only radiate acoustic waves in water through the first-order bending vibration mode of the shell. In the emission response curve, there is a relatively deep trough between its first-order vibration response peak and the subsequent second-order, third-order, etc. response peaks. Therefore, how to use the multi-modal coupling technology to couple multiple different vibration modes of the V-type flextensional transducer to form broadband characteristics has become the main technical problem. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problem in the prior art that the traditional V-type flextensional transducer cannot achieve broadband transmission due to the trough in the acoustic radiation response curves of the first-order bending axisymmetric vibration and the subsequent higher-order bending axisymmetric vibrations. Thus, a broadband V-type flextensional transducer with a variable curvature shell, a method for radiating acoustic waves in water, and a Cymbal array are provided. By changing the second-order bending axisymmetric vibration mode, it can be coupled with the first-order mode, thereby eliminating the trough in the response curve and achieving broadband transmission characteristics. Thus, a variable curvature shell V-type flextensional transducer, a working method, and a Cymbal array with the characteristics of both low frequency, small size, high power, and broadband transmission are realized.

[0006] To solve the above technical problems, the broadband V-type flextensional transducer with a variable curvature shell provided by the technical solution of the present invention includes:

[0007] A shell, comprising: an upper shell 1 and a lower shell 2; wherein the upper shell 1 comprises a protruding portion 11, a recessed portion 12, a pre-tightening portion 13 and a fixing portion 14; wherein the protruding portion 11 provides a positive curvature radiation surface, having a convex surface extending from the inside of the shell to the outside of the shell; the recessed portion 12 provides a negative curvature radiation surface, transitionally connected between the protruding portion 11 and the pre-tightening portion 13, having an arc-shaped cross-section, and the center of the arc is located outside the shell; the fixing portion 14 comprises a plurality of portions extending outwardly in different radial directions of the pre-tightening portion 13, each portion being arranged in a circumferential direction of the pre-tightening portion 13 and connected to the pre-tightening portion 13; the structure of the lower shell 2 is mirror-symmetrical with the upper shell 1 along a horizontal plane; the pre-tightening portion 13 of the lower shell 2 and the pre-tightening portion 13 of the upper shell 1 abut against each other and are detachably connected; and

[0008] The vibrator is disposed in the upper shell 1 and the lower shell 2 and is fixedly connected to the upper shell 1 and the lower shell 2.

[0009] As an improvement of the above-mentioned transducer, each part of the fixing portion 14 is provided with a threaded hole 15 and a through hole 16 along the axial direction of the pre-tightening portion 13; the pre-tightening portion 13 of the lower shell 2 is detachably connected to the pre-tightening portion 13 of the upper shell 1 by bolts, and the bolts penetrate into the threaded hole 15 of the pre-tightening portion 13 and the threaded hole 15 of the pre-tightening portion 13 of the upper shell 1; the shell is connected to an external device through the through hole 16, or the through hole is used as a fulcrum for hoisting.

[0010] As an improvement of the above transducer, the protruding portion 11, the recessed portion 12, the pre-tightening portion 13 and the fixing portion 14 of the upper shell 1 are integrally formed; the protruding portion 11, the recessed portion 12, the pre-tightening portion 13 and the fixing portion 14 of the lower shell 2 are integrally formed.

[0011] As an improvement of the above transducer, the protruding portion 11, the recessed portion 12 and the pre-tightening portion 13 are all axisymmetric rotational body structures.

[0012] As an improvement of the above transducer, the curvature radius of the convex surface of the protruding portion 11 is greater than the curvature radius of the arc-shaped cross section of the recessed portion 12 .

[0013] As an improvement of the above transducer, the fixing portion 14 includes four parts; the four parts of the fixing portion 14 form a circular array on the periphery of the pre-tightening portion 13, and the angle between two adjacent parts is 90°.

[0014] As an improvement of the above transducer, it further includes a silicone pad 4, which is arranged on the periphery of the vibrator and connected to the fixing parts 14 of the upper shell 1 and the lower shell 2, so as to seal the shell.

[0015] As an improvement of the above transducer, the types of the vibrators include: a piezoelectric circular-ring vibrator 3, a piezoelectric disk vibrator, and a rare-earth Terfenol-D vibrator; among them, the piezoelectric circular-ring vibrator 3 includes a piezoelectric ceramic mosaic ring 31 and epoxy glass fiber 32; wherein, the piezoelectric ceramic mosaic ring 31 is formed by splicing a plurality of piezoelectric ceramic strips along the circumferential direction, and every two piezoelectric ceramic strips are connected in a manner of mechanical series and electrical parallel. After the piezoelectric ceramic mosaic ring 31 is spliced, it is wound and fixed by the epoxy glass fiber 32.

[0016] To achieve another object of the present invention, the present invention also provides a method for radiating sound waves in water, which uses the variable-curvature shell broadband V-type flextensional transducer as described above, and includes the following steps:

[0017] Apply alternating signals with different frequencies to the piezoelectric circular-ring vibrator 3 through an external cable. The piezoelectric circular-ring vibrator 3 performs radial expansion and contraction movements inside the upper shell 1 and the lower shell 2, drives the pre-tightening part 13 to perform radial expansion and contraction movements, and then transmits the vibration to the protruding part 11 and the concave part 12, realizing the displacement amplification effect, converting the small vibration displacement of the piezoelectric circular-ring vibrator 3 into the large vibration displacement of the upper shell 1 and the lower shell 2, and realizing the overall expansion and contraction movement in water, thereby radiating sound waves in water.

[0018] As another object of the present invention, the present invention also provides a Cymbal array, which includes the variable-curvature shell broadband V-type flextensional transducer as described above. Among them, the transducer is miniaturized by using a small driving vibrator to form a Cymbal transducer and form an array.

[0019] Compared with the prior art, the advantages of the present invention are as follows: The variable-curvature shell broadband V-type flextensional transducer, the method for radiating sound waves in water, and the Cymbal array of the present invention have the following advantages:

[0020] 1. The variable-curvature shell broadband V-type flextensional transducer provided by the present invention comprises: an upper shell 1, including a protruding portion 11, a recessed portion 12, a pre-tightening portion 13 and a fixing portion 14. The recessed portion 12 is located on the periphery of the protruding portion 11 and is connected to the pre-tightening portion 13. The fixing portion 14 extends outward from four directions of the pre-tightening portion 13 into four parts, and each part is provided with a threaded hole 15 and a through hole 16; a lower shell 2, which is symmetrically arranged with the upper shell 1 up and down and has the same features as the upper shell 1; a piezoelectric circular ring vibrator 3, including a piezoelectric ceramic mosaic circular ring 31 and epoxy glass fiber 32. The piezoelectric circular ring vibrator 3 is arranged inside the upper shell 1 and the lower shell 2 and is fixedly connected to the upper shell 1 and the lower shell 2; a silica gel pad 4, which is arranged on the periphery of the piezoelectric circular ring vibrator 3 and is fixedly connected to the upper shell 1 and the lower shell 2. By applying an alternating signal to the piezoelectric circular ring vibrator 3, the piezoelectric circular ring vibrator 3 expands and contracts radially inside the upper shell 1 and the lower shell 2, driving the pre-tightening portion 13 to expand and contract radially. The vibration will be transmitted to the protruding portion 11 and the recessed portion 12 of the shell, realizing the displacement amplification effect, converting the small vibration displacement of the piezoelectric circular ring vibrator 3 into the large vibration displacement of the upper shell 1 and the lower shell 2, and thus radiating sound waves in water. The upper and lower shell 2 parts of the variable-curvature shell broadband V-type flextensional transducer adopt a combination of the protruding portion 11 and the recessed portion 12, and the recessed portion 12 is on the periphery of the protruding portion 11. By this design method, it replaces the structure in which the whole shell of the traditional V-type flextensional transducer is the protruding portion 11. Without changing the overall structural mode of the traditional V-type flextensional transducer, the upper and lower shells 2 are artificially divided into two radiation surfaces with opposite positive and negative curvatures. This structure can change the second-order bending vibration axisymmetric mode of the traditional V-type flextensional transducer. The second-order vibration mode of the traditional V-type flextensional transducer is that the whole protruding radiation surface is divided into two parts and expands and contracts respectively, with a phase inversion region. However, the changed second-order vibration mode becomes an overall expansion or contraction mode with the recessed portion 12 radiation surface as the main radiation region, which is opposite to the phase of the traditional second-order mode. Therefore, it can be coupled with the first-order mode and the third-order mode of the transducer to realize the coupling of the first three-order bending axisymmetric vibrations to form broadband characteristics.

[0021] 2. In the variable-curvature shell broadband V-type flextensional transducer provided by the present invention, the protruding portion 11, the recessed portion 12 and the pre-tightening portion 13 included in the upper and lower shells 2 are all axisymmetric of revolution structures. Since the variable-curvature V-type flextensional transducer only changes the protruding portion 11 and the recessed portion 12 of the radiation surface part of the upper and lower shells 2, and its overall structure has not changed greatly compared with the traditional V-type flextensional transducer (such as shell thickness, oscillator assembly, etc.), its first-order bending axisymmetric vibration is basically the same as that of the traditional V-type flextensional transducer in the prior art in terms of vibration mode and radiation ability, and does not reduce the low-frequency and high-power characteristics of the traditional V-type flextensional transducer in the first-order vibration mode.

[0022] 3. The broadband V-type flextensional transducer with a variable-curvature housing provided by the present invention has a larger radius of curvature of the convex portion 11 than that of the concave portion 12. Since the second-order bending axisymmetric vibration mode of the broadband V-type flextensional transducer with a variable-curvature housing is a vibration with the concave portion 12 as the main radiation area, in order to achieve good broadband emission characteristics, the design of the radius of curvature of the concave portion 12 is crucial. If the concave portion 12 is too small, the broadband V-type flextensional transducer with a variable-curvature housing will return to the structure of a traditional V-type; if the concave portion 12 is too large, the emission response peak of the second-order vibration will also be relatively high. Even if it can be coupled with the first-order vibration, it is difficult to achieve a smooth broadband characteristic. Therefore, when the radius of curvature of the convex portion 11 is greater than that of the concave portion 12, the broadband V-type flextensional transducer with a variable-curvature housing can additionally increase the broadband radiation characteristic without losing the low-frequency and high-power characteristics.

[0023] 4. The broadband V-type flextensional transducer with a variable-curvature housing provided by the present invention has a piezoelectric ceramic mosaic ring 31 formed by splicing a plurality of piezoelectric ceramic strips along the circumferential direction, and every two piezoelectric ceramic strips are connected in a manner of mechanical series and electrical parallel. Since the present invention improves the broadband emission performance by changing the structure of the radiation surface of the V-type flextensional transducer housing, and the advantages brought by the structural optimization have less relevance to what kind of driving oscillator is inside, it can be driven by different types of oscillators, and different transducers and applications can also be realized by changing the transducer size. For example: reducing the larger housing in proportion, performing miniaturization processing, and then driving it with a small piezoelectric cylinder 5 or a piezoelectric disc 6, a small-sized Cymbal transducer can be formed, and the broadband performance of the Cymbal transducer can also be improved. Then, by performing a close-packed array design on it, it can be used for more applications such as reception or directivity.

[0024] 5. The broadband V-type flextensional transducer with a variable-curvature housing provided by the present invention has a body in a rotary body structure, and the lower housing 2 and the upper housing 1 are symmetrically arranged, making it easier for the transducer to generate an axisymmetric and excitable bending vibration mode, and reducing redundant and unnecessary bending vibration modes.

[0025] 6. The broadband V-type flextensional transducer with a variable-curvature housing provided by the present invention has the convex portion 11, the concave portion 12, the pre-tightening portion 13, and the fixing portion 14 of the upper housing 1 and the lower housing 2 as integrally formed parts, ensuring the overall stability of the housing, avoiding nodes at the connection of the convex portion 11 and the concave portion 12 of multiple split structures, and thus ensuring the accuracy of the broadband V-type flextensional transducer with a variable-curvature housing.

[0026] The summary of the invention is provided to introduce a selection of concepts in a simplified form, which will be further described in the detailed implementation manners below. The summary of the invention is not intended to identify the important features or essential features of the present disclosure, nor is it intended to limit the scope of the present disclosure. Brief Description of the Drawings

[0027] Figure 1 is a schematic diagram of the overall structure of the variable-curvature shell broadband V-type flextensional transducer provided by the present invention;

[0028] Figure 2 is Figure 1 an explosion diagram of;

[0029] Figure 3 is Figure 1 a sectional view of;

[0030] Figure 4 is the wiring method of the built-in piezoelectric ceramic mosaic ring of the variable-curvature shell broadband V-type flextensional transducer provided by the present invention;

[0031] Figure 5 is a comparison diagram of the structures and curvatures of the variable-curvature shell broadband V-type flextensional transducer and the traditional V-type flextensional transducer in the two-dimensional axisymmetric plane provided by the present invention;

[0032] Figure 6 is the vibration mode diagram of the first three bending vibration modes of the variable-curvature shell broadband V-type flextensional transducer in the two-dimensional axisymmetric plane provided by the present invention;

[0033] Figure 7 is a comparison diagram of the transmitting voltage response curves of the variable-curvature shell broadband V-type flextensional transducer and the traditional V-type flextensional transducer in the low-frequency band provided by the present invention;

[0034] Figure 8 is a comparison diagram of the transmitting voltage response curves of the variable-curvature shell broadband V-type flextensional transducer and the traditional V-type flextensional transducer in the middle-frequency band after the light miniaturization treatment provided by the present invention;

[0035] Figure 9 is the variable-curvature shell broadband V-type flextensional transducer after the light miniaturization treatment with a piezoelectric circular tube as the driving oscillator;

[0036] Figure 10 is the variable-curvature shell broadband V-type flextensional transducer after the light miniaturization treatment with a piezoelectric circular plate as the driving oscillator.

[0037] Figure reference labels

[0038] 1 - Upper shell; 11 - Protruding part; 12 - Recessed part; 13 - Pre-tightening part; 14 - Fixed part; 15 - Threaded hole; 16 - Through hole; 2 - Lower shell; 3 - Piezoelectric circular ring oscillator; 31 - Piezoelectric ceramic mosaic ring; 32 - Epoxy fiberglass; 4 - Silicone pad; 5 - Piezoelectric circular tube; 6 - Piezoelectric circular plate. Detailed implementation manners

[0039] The following further illustrates the technical solutions provided by the present invention in combination with embodiments.

[0040] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0041] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0042] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0043] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0044] Embodiment 1

[0045] Please refer to Figures 1 to 7 As shown, this embodiment provides a variable-curvature shell broadband V-type flextensional transducer, including:

[0046] A shell, including: an upper shell 1 and a lower shell 2; wherein, the upper shell 1 includes a convex part 11, a concave part 12, a pre-tightening part 13 and a fixing part 14; wherein, the convex part 11 provides a positive-curvature radiation surface, having a convex surface extending from the inside of the shell to the outside of the shell; the concave part 12 provides a negative-curvature radiation surface, which transitions and connects between the convex part 11 and the pre-tightening part 13, having an arc-shaped cross-section, and the center of the arc is located outside the shell; the fixing part 14 includes several parts extending outward in different radial directions along the pre-tightening part 13, and each part is arranged in the circumferential direction of the pre-tightening part 13 and connected to the pre-tightening part 13.

[0047] The lower shell 2 has a structure that is mirror-symmetrical with the upper shell 1 along a horizontal plane and has the same features as the upper shell 1; the pre-tightening portion 13 of the lower shell 2 abuts against the pre-tightening portion 13 of the upper shell 1 and is detachably connected;

[0048] The vibrator is disposed in the upper shell 1 and the lower shell 2 and is fixedly connected to the upper shell 1 and the lower shell 2.

[0049] The types of vibrators may include: piezoelectric ring vibrators, piezoelectric disc vibrators and rare earth Terfenol-D vibrators. This embodiment uses the piezoelectric ring vibrator 3 as an example. It is worth noting that simulations have confirmed that various vibrators can be used.

[0050] In some optional embodiments, each part of the fixing portion 14 is provided with a threaded hole 15 and a through hole 16 along the axial direction of the pre-tightening portion 13; the pre-tightening portion 13 of the lower shell 2 is detachably connected to the pre-tightening portion 13 of the upper shell 1 by bolts, and the bolts penetrate the threaded holes 15 of the pre-tightening portion 13 and the threaded holes 15 of the pre-tightening portion 13 of the upper shell 1. The shell is connected to an external device through the through hole 16, or the through hole is used as a fulcrum for hoisting. The external device can be a structure such as a platform.

[0051] In some optional embodiments, the recessed portion 12 is located at the periphery of the protruding portion 11 and is arranged around the protruding portion 11. The inner edge of the recessed portion 12 is connected to the outer edge of the protruding portion 11, and the outer edge of the recessed portion 12 is connected to the top of the pre-tightening portion 13.

[0052] An alternating signal is applied to the piezoelectric ring oscillator 3 through an external cable, and the piezoelectric ring oscillator 3 radially expands and contracts inside the upper shell 1 and the lower shell 2, driving the pre-tightening part 13 to radially expand and contract, and the vibration will be transmitted to the protruding part 11 and the recessed part 12 of the shell, realizing the displacement amplification effect, so that the small vibration displacement of the piezoelectric ring oscillator 3 is converted into a large vibration displacement of the upper shell 1 and the lower shell 2, thereby radiating sound waves in the water.

[0053] The upper housing 1 and the lower housing 2 of the variable-curvature shell broadband V-type flextensional transducer adopt a combination of a convex part 11 and a concave part 12, and the concave part 12 is on the periphery of the convex part 11. This design method replaces the structure in which the whole shell of the traditional V-type flextensional transducer is a convex part. Without changing the overall structural mode of the traditional V-type flextensional transducer, the upper housing 1 and the lower housing 2 are artificially divided into two radiation surfaces with opposite positive and negative curvatures, and this structure can change the second-order bending vibration axisymmetric mode of the traditional V-type flextensional transducer. The second-order vibration mode of the traditional V-type flextensional transducer is that the whole convex radiation surface is divided into two parts that expand and contract respectively, and there is a phase inversion region. The changed second-order vibration mode becomes an overall expansion or contraction mode with the concave part radiation surface as the main radiation region, which is opposite to the phase of the traditional second-order mode. Therefore, it can be coupled with the first-order mode and the third-order mode of the transducer to realize the coupling of the first three-order bending axisymmetric vibrations to form broadband characteristics.

[0054] In this embodiment, the convex part 11, the concave part 12 and the pre-tightening part 13 included in the upper housing 1 and the lower housing 2 are all axisymmetric rotary body structures. Since the variable-curvature shell broadband V-type flextensional transducer only changes the convex part 11 and the concave part 12 of the radiation surface of the upper and lower housings, its overall structure has not changed greatly compared with the traditional V-type flextensional transducer (such as shell thickness, oscillator assembly, etc.). Therefore, its first-order bending axisymmetric vibration is basically the same as that of the traditional V-type flextensional transducer in the prior art in terms of vibration mode and radiation ability, and does not reduce the low-frequency and high-power characteristics of the traditional V-type flextensional transducer in the first-order vibration mode.

[0055] In some alternative embodiments, the radius of curvature of the convex surface of the convex part 11 is greater than the radius of curvature of the arc cross-section of the concave part 12. Since the second-order bending axisymmetric vibration mode of the variable-curvature V-type flextensional transducer is the vibration with the concave part 12 as the main radiation region, in order to achieve good broadband emission characteristics, the design of the radius of curvature of the concave part 12 is crucial. If the concave part 12 is too small, the variable-curvature V-type flextensional transducer will return to the traditional V-type structure; if the concave part 12 is too large, the emission response peak of the second-order vibration will also be higher, and even if it can be coupled with the first-order vibration, it is difficult to achieve a smooth broadband characteristic. Therefore, when the radius of curvature of the convex surface of the convex part 11 is greater than the radius of curvature of the arc cross-section of the concave part 12, the variable-curvature V-type flextensional transducer can additionally increase the broadband radiation characteristic without losing the low-frequency and high-power characteristics. It should be noted that according to the simulation results, when the radius of curvature of the convex surface of the convex part 11 is less than or equal to the radius of curvature of the arc cross-section of the concave part 12, the broadband emission characteristic can still maintain the normal level, but when the radius of curvature of the convex surface of the convex part 11 is greater than the radius of curvature of the arc cross-section of the concave part 12, the broadband effect is better.

[0056] In some alternative embodiments, the piezoelectric ring oscillator 3 includes a piezoelectric ceramic mosaic ring 31 and an epoxy fiberglass 32. The piezoelectric ceramic mosaic ring 31 is formed by splicing a plurality of piezoelectric ceramic strips along the circumferential direction, and every two piezoelectric ceramic strips are connected in a manner of mechanical series and electrical parallel. After the piezoelectric ceramic mosaic ring 31 is spliced, it is tightly wound and fixed by the epoxy fiberglass 32. Since the broadband emission performance is improved by changing the structure of the radiation surface of the V-type flexural transducer housing in this embodiment, and the advantages brought by the structural optimization have less relevance to what kind of driving oscillator is inside, different types of oscillators can be used for driving, and different transducers and applications can be achieved by changing the transducer size. For example, a larger housing can be proportionally reduced in size for miniaturization, and then driven by a small piezoelectric circular tube or piezoelectric circular plate to form a small-sized Cymbal transducer, which can also achieve an improvement in the broadband performance of the Cymbal transducer. By further designing a close-packed array, it can be used for more applications such as reception or directivity.

[0057] In some alternative embodiments, the lower housing 2 and the upper housing 1 are symmetrically arranged, making it easier for the transducer to generate an axisymmetric, excitable flexural vibration mode and reducing redundant and unnecessary flexural vibration modes.

[0058] In some alternative embodiments, the protruding portions 11, the recessed portions 12, the pre-tightening portions 13, and the fixing portions 14 of the upper housing 1 and the lower housing 2 are integrally formed parts, ensuring the overall stability of the housing, avoiding nodes at the joints of the protruding and recessed parts of multiple split structures, and thus ensuring the accuracy of the variable-curvature housing broadband V-type flexural transducer.

[0059] In some alternative embodiments, the fixing portion 14 includes four parts; the four parts of the fixing portion 14 form a circumferential array around the pre-tightening portion 13, with a 90° interval between each two.

[0060] In some alternative embodiments, a silica gel pad 4 is further included, which is disposed outside the piezoelectric ring oscillator 3 and connected to the fixing portions 14 of the upper housing 1 and the lower housing 2, and is used for sealing the housing to prevent glue leakage during subsequent potting.

[0061] Please refer to Figure 7 As shown, the variable-curvature housing broadband V-type flexural transducer is formed by splicing 120 piezoelectric ceramic strips along the circumferential direction The piezoelectric ceramic mosaic ring is used as a piezoelectric ring oscillator to drive a variable-curvature V-type flextensional transducer with a shell thickness of 4 mm. The curvature radius of the convex part is 160 mm, and the curvature radius of the concave part is 49 mm. The resonance frequency of the first-order bending vibration axisymmetric mode of the transducer is about 1.7 kHz, the resonance frequency of the changed second-order vibration mode is about 3.3 kHz, and the resonance frequency of the third-order vibration mode is about 5.2 kHz. The first three vibration modes can be coupled to form a broadband characteristic. The peak values of the transmitting voltage responses of the three modes are 137.1 dB, 137.3 dB, and 141.5 dB respectively. A broadband with an in-band fluctuation of less than 3 dB can be formed in the range of 1.5 kHz - 3.5 kHz, and a broadband with an in-band fluctuation of less than 6 dB can be formed in the range of 1.5 kHz - 7 kHz. The bandwidth exceeds 2 octaves, replacing the deeper valleys in the traditional curve. At the same time, when the first-order frequency is the same as the traditional one, the calculated maximum sound source level can reach 198 dB, realizing the characteristics of combining low frequency, high power, and broadband of the variable-curvature V-type flextensional transducer.

[0062] Please refer to Figure 8 As shown, in another embodiment, a light and miniaturized treatment is carried out on the variable-curvature shell broadband V-type flextensional transducer. 24 piezoelectric ceramic strips are pieced together along the circumferential direction to form The piezoelectric ceramic mosaic ring is used as a piezoelectric ring oscillator to drive a variable-curvature V-type flextensional transducer with a shell thickness of 3 mm. The curvature radius of the convex part is 45 mm, and the curvature radius of the concave part is 15 mm. The resonance frequency of the first-order bending vibration axisymmetric mode of the transducer is about 6.8 kHz, the resonance frequency of the changed second-order vibration mode is about 12 kHz, the resonance frequency of the third-order vibration mode is about 14.6 kHz, and the resonance frequency of the fourth-order vibration mode is about 19.6 kHz. The first four vibration modes are coupled to form a broadband characteristic. The peak values of the transmitting voltage responses of the four modes are 129.4 dB, 132.5 dB, 133.9 dB, and 129.9 dB respectively. A broadband with an in-band fluctuation of less than 6 dB can be formed in the range of 6.2 kHz - 20.1 kHz, and the bandwidth is about 1.7 octaves, realizing the characteristics of combining low frequency, high power, and broadband of the variable-curvature V-type flextensional transducer. This also proves that the broadband characteristic of the shell structure has nothing to do with the driving oscillator inside the transducer, and the working frequency band of the transducer can be adjusted by changing the overall ratio of the shell and the material or structure of the oscillator.

[0063] Embodiment 2

[0064] This embodiment provides a method for radiating sound waves in water, using the variable-curvature shell broadband V-type flextensional transducer provided in Embodiment 1, including the following steps:

[0065] An alternating signal with different frequencies is applied to the piezoelectric ring oscillator 3 through an external cable. The piezoelectric ring oscillator 3 performs radial expansion and contraction movements inside the upper housing 1 and the lower housing 2, driving the pre-tightening part 13 to perform radial expansion and contraction movements. The vibration will be transmitted to the protruding part 11 and the concave part 12, realizing the displacement amplification effect, converting the small vibration displacement of the piezoelectric ring oscillator 3 into the large vibration displacement of the upper housing 1 and the lower housing 2, and realizing the overall expansion and contraction movement in water, thereby radiating sound waves in water.

[0066] Embodiment 3

[0067] For the Cymbal array provided in this embodiment, please refer to Figure 9 As shown, it includes the variable-curvature shell broadband V-type flextensional transducer provided in Embodiment 1. The transducer is miniaturized by using a small driving oscillator to form a Cymbal transducer and form an array. In this embodiment, the small driving oscillator directly drives the shell through a piezoelectric circular tube 5 or a piezoelectric circular plate 6. The relatively large piezoelectric ring oscillator 3 drives a relatively large flextensional shell to achieve the characteristics of low frequency and high power. In this embodiment, the transducer is reduced in volume, and the inside is directly driven by a piezoelectric circular tube 5 ( Figure 9 as shown) or a piezoelectric circular plate 6 ( Figure 10 as shown), so as to perform lightweight miniaturization processing on the transducer, which can be used at high frequencies and is named a cymbal transducer. Essentially, the working and driving mechanisms of using a large oscillator (such as the piezoelectric ring oscillator 3) and using a small oscillator (such as the piezoelectric circular tube 5 or the piezoelectric circular plate 6) are the same.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the embodiments, those of ordinary skill in the art should understand that any modification or equivalent replacement of the technical solutions of the present invention does not depart from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A variable curvature shell broadband V-type flextensional transducer, comprising: A shell, comprising: an upper shell (1) and a lower shell (2); wherein the upper shell (1) comprises a protruding portion (11), a recessed portion (12), a pre-tightening portion (13) and a fixing portion (14); wherein the protruding portion (11) provides a positive curvature radiation surface, having a convex surface extending from the inside of the shell to the outside of the shell; wherein the recessed portion (12) provides a negative curvature radiation surface, transitionally connected between the protruding portion (11) and the pre-tightening portion (13), having an arc-shaped cross-section, the center of the arc being located outside the shell; wherein the fixing portion (14) comprises a plurality of portions extending outwardly in different radial directions of the pre-tightening portion (13), wherein each portion is arranged in a circumferential direction of the pre-tightening portion (13) and connected to the pre-tightening portion (13); wherein the structure of the lower shell (2) is mirror-symmetrical with that of the upper shell (1) along a horizontal plane; wherein the pre-tightening portion (13) of the lower shell (2) and the pre-tightening portion (13) of the upper shell (1) abut against each other and are detachably connected; and The vibrator is arranged in the upper shell (1) and the lower shell (2), and is fixedly connected to the upper shell (1) and the lower shell (2).

2. The variable-curvature shell broadband V-type flextensional transducer according to claim 1, characterized in that, Each part of the fixing portion (14) is provided with a threaded hole (15) and a through hole (16) along the axial direction of the pre-tightening portion (13); the pre-tightening portion (13) of the lower shell (2) is detachably connected to the pre-tightening portion (13) of the upper shell (1) by means of bolts, and the bolts penetrate into the threaded hole (15) of the pre-tightening portion (13) and the threaded hole (15) of the pre-tightening portion (13) of the upper shell (1); the shell is connected to an external device via the through hole (16), or the through hole is used as a fulcrum for hoisting.

3. The variable-curvature shell broadband V-type flextensional transducer according to claim 1, wherein The protruding portion (11), the recessed portion (12), the pre-tightening portion (13) and the fixing portion (14) of the upper shell (1) are integrally formed; the protruding portion (11), the recessed portion (12), the pre-tightening portion (13) and the fixing portion (14) of the lower shell (2) are integrally formed.

4. The variable-curvature shell broadband V-type flextensional transducer according to claim 1, wherein The protruding portion (11), the recessed portion (12) and the pre-tightening portion (13) are all axisymmetric rotational body structures.

5. The variable-curvature shell broadband V-type flextensional transducer according to claim 1, characterized in that, The radius of curvature of the convex surface of the protruding portion (11) is greater than the radius of curvature of the arc-shaped cross section of the recessed portion (12).

6. The variable-curvature shell broadband V-type flextensional transducer according to claim 1, wherein The fixing portion (14) comprises four parts; the four parts of the fixing portion (14) form a circular array on the periphery of the pre-tightening portion (13), and the angle between two adjacent parts is 90°.

7. The variable-curvature shell broadband V-type flextensional transducer according to claim 1, characterized in that, It also includes a silicone pad 4, which is arranged on the periphery of the vibrator and connected to the fixing parts (14) of the upper shell (1) and the lower shell (2) to seal the shell.

8. The variable-curvature shell broadband V-type flextensional transducer according to claim 1, wherein The types of the vibrators include: piezoelectric ring vibrators (3), piezoelectric disc vibrators and rare earth Terfenol-D vibrators; wherein, The piezoelectric ring vibrator (3) comprises a piezoelectric ceramic inlaid ring (31) and epoxy glass filaments (32); wherein the piezoelectric ceramic inlaid ring (31) is formed by a plurality of piezoelectric ceramic strips being assembled in a circumferential direction, and every two piezoelectric ceramic strips are connected in a mechanical series and electrical parallel manner; and after being assembled, the piezoelectric ceramic inlaid ring (31) is wound and fixed by the epoxy glass filaments (32).

9. A method for radiating acoustic waves in water, using the variable-curvature shell broadband V-type flextensional transducer according to any one of claims 1-8, comprising the following steps: Applying alternating signals of different frequencies to the piezoelectric circular ring oscillator (3) through an external cable. The piezoelectric circular ring oscillator (3) performs radial expansion and contraction movements inside the upper shell (1) and the lower shell (2), driving the pre-tightening part (13) to perform radial expansion and contraction movements, and then transmitting the vibration to the protruding part (11) and the concave part (12), realizing the displacement amplification effect, converting the small vibration displacement of the piezoelectric circular ring oscillator (3) into the large vibration displacement of the upper shell (1) and the lower shell (2), and realizing the overall expansion and contraction movement in water, thereby radiating acoustic waves in water.

10. A Cymbal array, comprising the variable curvature shell broadband V-type flextensional transducer according to any one of claims 1-7, wherein, The transducer is miniaturized using a small driving oscillator to form an array composed of Cymbal transducers.

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