Concave-convex beam type low-frequency directional flextensional transducer

Abstract

The invention relates to the field of underwater acoustic transducers, in particular to a concave-convex beam type low-frequency directional flextensional transducer which comprises an outwards-convex bent beam (1), an inwards-concave bent beam (2), a top wall, a bottom wall and an oscillator assembly (3). The convex bent beam (1) and the concave bent beam (2) are oppositely arranged and have the same height, the tops of the convex bent beam and the concave bent beam are respectively connected with the top wall, and the bottoms of the convex bent beam and the concave bent beam are respectively connected with the bottom wall to jointly form an asymmetric radiation shell; the thickness or the curvature radius of the convex surface of the outwards-convex bent beam (1) is different from that of the concave surface of the inwards-concave bent beam (2), and therefore the modal radiation component proportion and the coupling strength of the transducer are adjusted by adjusting the thickness or the curvature radius of the convex surface or / and the concave surface. The asymmetry of the concave-convex shell is utilized, excitation and coupling of a monopole mode and a dipole mode of the transducer are structurally solved, and low-frequency heart-shaped directivity can be achieved.

Description

Technical Field

[0001] The invention relates to the field of underwater acoustic transducers, and in particular to a concave-convex beam type low-frequency directional flextensional transducer. Background Art

[0002] Flextensional transducers are commonly used underwater acoustic transducers that have the characteristics of low frequency and small size. Their working principle is that the shell with amplitude amplification effect is driven by a longitudinal stretching vibrator or a radial pulsating ring to generate bending vibration to radiate sound energy. However, the geometric size of the flextensional transducer is generally much smaller than the working wavelength, and most of the shell surface vibrates in phase, which determines that it has basically no directivity.

[0003] In order to achieve directional emission of flextensional transducers, common solutions are to add a large baffle or use two base arrays with a phase difference of one quarter wavelength, but these methods will result in the equipment being too large, too heavy and expensive. For the above reasons, scholars at home and abroad began to study how to make a single transducer itself have directivity in a single direction. In 1984, JLButler and A.Clark first proposed a magnetostrictive-piezoelectric hybrid excitation method to achieve directional emission. Its working principle is to use the inherent 90° phase difference of magnetostrictive and piezoelectric materials and a quarter-wavelength vibrator to achieve the effect of vibration cancellation at one end of the transducer and vibration enhancement at the other end. In 1988, JLButler proposed to divide the driving vibrators of the IV-type flextensional transducer into two groups and excite them separately, and to excite the odd-order and even-order modes of the transducer by changing the voltage amplitude and phase of the two groups of driving vibrators, and to couple the two modes to achieve directional emission. Using a similar principle, in 2001, J.Zhang studied the directional Cymbal transducer. Stephen Butler designed a directional Ⅶ-type flextensional transducer in 2010. The disadvantage of the above method is that the circuit must be designed according to the structural characteristics of the transducer itself, which increases the configuration of the transducer's electrical system and is not convenient to use. In addition, the design of the dual excitation vibrator increases the volume and weight of the transducer. When the transducer works in the dipole mode, the driving vibrator will also experience bending vibration. In the high-power mode, it will be mechanically damaged due to the internal shearing of the functional material, affecting the high-power emission of the transducer.

[0004] Therefore, it is necessary to design a low-frequency directional transducer with simple circuit driving and high-power transmission. Summary of the invention

[0005] The object of the present invention is to overcome the above-mentioned defects of the prior art, thereby providing a concave-convex beam type low-frequency directional flextensional transducer.

[0006] In order to solve the above technical problems, the technical solution of the present invention provides a concave-convex beam type low-frequency directional flextensional transducer, comprising: an outer convex curved beam 1, an inner concave curved beam 2, a top wall, a bottom wall and a vibrator assembly 3; wherein,

[0007] The convex curved beam 1, the concave curved beam 2, the top wall and the bottom wall are continuous solid structures. The convex curved beam 1 and the concave curved beam 2 are arranged opposite to each other and have the same height. The tops of the two are respectively connected to the top wall, and the bottoms of the two are respectively connected to the bottom wall, so as to form an asymmetric radiation shell together; wherein,

[0008] The vibrator assembly 3 includes one or more sets of parallel and evenly arranged driving vibrators, and the driving vibrators are connected to the inside of the radiation shell along the height direction of the transducer;

[0009] The convex curved beam 1 is vertically arranged along the height direction, and has at least one convex surface with curvature protruding from the radiation shell toward the outside, and the center line of the convex surface is perpendicular to the height direction;

[0010] The concave curved beam 2 is vertically arranged along the height direction, and has a concave surface with a curvature that is recessed from the outside into the radiation shell, and the center line of the concave surface is perpendicular to the height direction;

[0011] The thickness or curvature radius of the convex surface of the convex curved beam 1 is different from that of the concave surface of the concave curved beam 2, so that the modal radiation component proportion and coupling strength of the transducer can be adjusted by adjusting the thickness or curvature radius of the convex surface and / or the concave surface.

[0012] As an improvement of the above-mentioned transducer, the radiation shell has a first side surface, a second side surface, a third side surface and a fourth side surface, and the projection of the first side surface, the second side surface, the third side surface and the fourth side surface on the bottom wall after being enclosed is rectangular; the convex curved beam 1 is located on the first side surface, and the concave curved beam 2 is located on the third side surface; the second side surface and the fourth side surface are hollow; the projection shape of the convex curved beam 1 on the third side surface is rectangular, and the projection shape on the second side surface is one or more continuous arcs; the projection shape of the concave curved beam 2 on the first side surface is rectangular, and the projection shape on the second side surface is one or more continuous arcs; the number of convex surfaces of the convex curved beam 1 is the same as the number of concave surfaces of the concave curved beam 2; the thickness ranges from 5 mm to 12 mm, and the thickness of the convex surface is less than or equal to the thickness of the concave surface.

[0013] As an improvement of the above transducer, the convex curved beam 1 has two continuous convex surfaces protruding from the radiation shell to the outside; the concave curved beam 2 has two continuous concave surfaces recessed from the outside to the inside of the radiation shell.

[0014] As an improvement of the above-mentioned transducer, the material of the convex curved beam 1 and the concave curved beam 2 is aluminum alloy, stainless steel or titanium alloy.

[0015] As an improvement of the above-mentioned transducer, the vibrator assembly 3 is a piezoelectric ceramic stack; the piezoelectric ceramic stack is formed by bonding an even number of piezoelectric ceramic sheets; the piezoelectric ceramic sheets are polarized along the thickness direction, and the polarization directions of two adjacent piezoelectric ceramic sheets are opposite. An electrode sheet is also arranged between every two piezoelectric ceramic sheets, and all the piezoelectric ceramic sheets are electrically connected in parallel.

[0016] As an improvement of the above transducer, the vibrator assembly 3 is a piezoelectric single crystal stack; the piezoelectric single crystal stack is formed by bonding an even number of piezoelectric single crystal pieces; an electrode sheet is arranged between every two piezoelectric single crystal pieces, and all the piezoelectric single crystal pieces are electrically connected in parallel.

[0017] As an improvement of the above transducer, the vibrator assembly 3 includes: at least one magnetostrictive rod 4, a permanent magnetic sheet 5 and an excitation coil 6; wherein the magnetostrictive rod 4 is arranged along the height direction, and when there are multiple magnetostrictive rods 4, the multiple magnetostrictive rods 4 are arranged along the height direction; the top and bottom of the magnetostrictive rod 4 are both connected to the permanent magnetic sheet 5; the excitation coil 6 is wound around the side wall of the magnetostrictive rod 4; when the excitation coil 6 is energized, the magnetic field generated acts on the magnetostrictive rod 4, causing the length of the magnetostrictive rod 4 to change; the permanent magnetic sheet 5 ensures the deformation degree of the magnetostrictive rod 4 by enhancing and stabilizing the magnetic field, thereby realizing the vibration of the vibrator.

[0018] As an improvement of the above transducer, the magnetostrictive rod 4 is made of magnetostrictive material, and the permanent magnet sheet 5 is made of high magnetic energy product material. Preferably, the magnetostrictive material is terbium dysprosium iron or iron gallium; the high magnetic energy product material is alloy permanent magnet material such as neodymium iron boron, aluminum nickel cobalt, samarium cobalt, or ferrite permanent magnet material.

[0019] As an improvement of the above transducer, the flextensional transducer is driven by a single-channel electrical signal during operation, so that the signal amplitude weighting coefficient and phase parameter do not need to be adjusted with frequency changes.

[0020] As an improvement of the above-mentioned transducer, the height of the vibrator assembly 3 is greater than the height of the inner wall of the radiation shell. When the vibrator assembly 3 is installed inside the radiation shell, the radiation shell is deformed, so that the pressure generated by the increased height of the inner wall of the radiation shell is used to fix the vibrator assembly 3 inside the radiation shell, thereby applying axial preload to the vibrator assembly 3.

[0021] Compared with the prior art, the advantages of the present invention are:

[0022] 1. The present invention utilizes the asymmetry of the concave-convex shell to truly solve the excitation and coupling of the monopole mode and the dipole mode of the transducer from a structural perspective, and can adjust the radiation component proportion and coupling strength of the two modes through structural parameter optimization design, which is conducive to achieving low-frequency cardioid directivity.

[0023] 2. The present invention adopts a single power supply drive, which reduces the electrical system configuration and can reduce the weight and cost of the launch system.

[0024] 3. The concave-convex beam type low-frequency directional flexural transducer provided by the present invention has a smaller bending amplitude of the driving vibrator within the working frequency band, smaller mechanical damage caused by shearing inside the functional material, and a larger power capacity of the transducer, which is conducive to high-power transmission.

[0025] 4. The concave-convex beam type low-frequency directional flexural transducer provided by the present invention has a cardioid directivity in the radiation direction, i.e., the x-axis direction, when the thickness of the concave surface is greater than the thickness of the convex surface, while the sound field intensities in the vibrator driving direction, i.e., the z-axis direction and the y-axis direction are consistent, that is, the spatial uniformity of the radiated sound field in the yz plane of the transducer is consistent. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a cross-sectional view of the structural schematic diagram of the concave-convex beam type low-frequency directional flextensional transducer of the present invention;

[0027] Figure 2 It is a schematic structural diagram of the concave-convex beam type low-frequency directional flextensional transducer of the present invention;

[0028] Figure 3 It is a schematic diagram of the structure of the concave-convex beam type low-frequency directional flextensional transducer in the present invention when the thickness of the convex curved beam is less than the thickness of the concave curved beam;

[0029] Figure 4 It is a schematic diagram of the structure of a concave-convex beam type low-frequency directional flextensional transducer with a double-section structure design in which the asymmetric radiation shell in the present invention is designed;

[0030] Figure 5 It is a cross-sectional view of the structural schematic diagram of a concave-convex beam type low-frequency directional flextensional transducer in which the vibrator assembly is driven by a magnetostrictive rod in the present invention;

[0031] FIG6( a ) is a first-order characteristic mode of the concave-convex beam type low-frequency directional flextensional transducer of the present invention, in which the concave shell vibration is dominant, and the concave shell and the convex shell vibrate in opposite directions;

[0032] FIG6( b ) is the second-order characteristic mode of the concave-convex beam type low-frequency directional flextensional transducer of the present invention, in which the convex shell vibration is dominant, and the concave shell and the convex shell vibrate in the same direction;

[0033] FIG. 7( a ) is a directivity diagram of the concave-convex beam type low-frequency directivity flextensional transducer of the present invention when operating in a monopole mode;

[0034] FIG7( b ) is a directivity diagram of the concave-convex beam type low-frequency directivity flextensional transducer of the present invention when it works in the dipole mode;

[0035] FIG7( c ) is a directivity diagram of the concave-convex beam type low-frequency directivity flextensional transducer of the present invention when forming a cardioid directivity emission;

[0036] Figure 8 It is a transmission voltage response curve diagram of the concave and convex surfaces of the concave-convex beam type low-frequency directional flextensional transducer of the present invention.

[0037] Figure ID

[0038] 1. Convex curved beam 2. Concave curved beam

[0039] 3. Vibrator assembly 4. Magnetostrictive rod

[0040] 5. Permanent magnet 6. Driving coil DETAILED DESCRIPTION

[0041] The present invention is further described below in conjunction with the accompanying drawings.

[0042] The working principle of the concave-convex beam type low-frequency directional flextensional transducer disclosed in the present invention is as follows:

[0043] FIG6 is a diagram showing the characteristic modes of the concave-convex beam type low-frequency directional flexural transducer of the present invention, wherein FIG6(a) is a first-order characteristic mode, which is dominated by the vibration of the concave shell, and the vibration directions of the concave shell and the convex shell are opposite; FIG6(b) is a second-order characteristic mode, which is dominated by the vibration of the convex shell, and the vibration directions of the concave shell and the convex shell are the same; these two modes are caused by the asymmetry of the radiation shell, and both only involve the first-order bending vibration of the curved shell, which determines its lower resonant frequency, and the maximum size of the transducer is much smaller than the wavelength.

[0044] Combined with Figure 7, when the concave-convex beam type low-frequency directional flextensional transducer vibrates in the first-order characteristic mode, it can be equivalent to a quasi-monopole acoustic radiation source, and its directivity diagram is shown in Figure 7(a); when the concave-convex beam type low-frequency directional flextensional transducer vibrates in the second-order characteristic mode, it can be equivalent to a quasi-dipole acoustic radiation source, and its directivity diagram is shown in Figure 7(b). When the first two order characteristic modes of the transducer are coupled, the vibration displacement generated by the main radiation surface is much greater than the vibration displacement generated by its relative radiation surface. At this time, the sound field can ensure that in addition to the dipole equivalent radiation source, there can also be a residual monopole sound source radiation component, thereby realizing a cardioid directional beam, and its directivity diagram is shown in Figure 7(c).

[0045] Example 1

[0046] Combination Figure 1 and Figure 2 The present invention discloses a concave-convex beam type low-frequency directional flextensional transducer, comprising an outward convex curved beam 1, an inward concave curved beam 2 and a vibrator assembly 3; wherein the outward convex curved beam 1 and the inward concave curved beam 2 are continuous solid structures; the vibrator assembly 3 is rigidly connected to the inner wall of the radiation shell.

[0047] The convex curved beam 1 and the concave curved beam 2 are arranged opposite to each other and have the same height. In this embodiment, the two top edges of the convex curved beam 1 and the concave curved beam 2 are connected to the square top wall, and the two bottom edges of the convex curved beam 1 and the concave curved beam 2 are connected to the bottom wall. In this embodiment, the top wall and the bottom wall are both square, and the convex curved beam 1, the concave curved beam 2, the top wall and the bottom wall are an integrated structure, which together constitute an asymmetric radiation shell.

[0048] The convex curved beam 1 is vertically arranged along the height direction, and has at least one convex surface with curvature protruding from the radiation shell toward the outside, and the center line of the convex surface is perpendicular to the height direction;

[0049] The concave curved beam 2 is vertically arranged along the height direction, and has a concave surface with a curvature that is recessed from the outside into the radiation shell, and the center line of the concave surface is perpendicular to the height direction;

[0050] The thickness or curvature radius of the convex surface of the convex curved beam 1 is different from that of the concave surface of the concave curved beam 2, so that the modal radiation component proportion and coupling strength of the transducer can be adjusted by adjusting the thickness or curvature radius of the convex surface and / or the concave surface.

[0051] The radiation housing has a first side surface, a second side surface, a third side surface and a fourth side surface, and the projection of the first side surface, the second side surface, the third side surface and the fourth side surface on the bottom wall after being surrounded is a rectangle;

[0052] The convex curved beam 1 is located on the first side surface, and the concave curved beam 2 is located on the third side surface; the second side surface and the fourth side surface are hollow;

[0053] The projection shape of the convex curved beam 1 on the third side is rectangular. In this embodiment, the projection shape of the convex curved beam 1 on the second side is an arc. It is worth noting that in other embodiments, the projection shape of the convex curved beam 1 on the second side may also be a plurality of continuous arcs, such as the double-section structure described in Example 3, which is two continuous arcs.

[0054] The projection shape of the inwardly concave curved beam 2 on the first side is a rectangle. In the present embodiment, the projection shape of the inwardly concave curved beam 2 on the second side is an arc. It is worth noting that in other embodiments, the projection shape of the inwardly concave curved beam 2 on the second side may also be a plurality of continuous arcs, such as the double-section structure described in Example 3, which is two continuous arcs.

[0055] The number of convex surfaces of the outward convex curved beam 1 is the same as the number of concave surfaces of the inward concave curved beam 2;

[0056] The thickness ranges from 5 mm to 12 mm. In this embodiment, the thickness of the convex surface is equal to the thickness of the concave surface. It is worth noting that in other embodiments, the thickness of the convex surface may also be less than the thickness of the concave surface, such as in Embodiment 2, the thickness of the convex surface is less than the thickness of the concave surface.

[0057] In this embodiment, the diameters and curvature radii of the convex curved beam 1 and the concave curved beam 2 are the same, and the radiation shells are both made of aluminum alloy.

[0058] The vibrator assembly in this embodiment includes four groups of piezoelectric ceramic stacks, which are evenly distributed inside the radiation shell along the y-axis direction of the transducer. Each group of piezoelectric ceramic stacks is formed by bonding an even number of piezoelectric ceramic sheets through epoxy resin. The piezoelectric ceramic sheets are polarized along the thickness direction, and the polarization directions of two adjacent piezoelectric ceramic sheets are opposite. An electrode sheet is also arranged between every two piezoelectric ceramic sheets, and all piezoelectric ceramic sheets are electrically connected in parallel to weld leads.

[0059] The maximum height of the vibrator assembly in this embodiment exceeds the maximum height of the inner wall of the radiation shell, which deforms the radiation shell in advance. The pressure generated by the increased height of the inner wall of the radiation shell is used to fix the vibrator assembly inside the radiation shell, thereby applying axial preload force to the vibrator assembly.

[0060] In addition to the piezoelectric ceramic stack, the vibrator assembly in this embodiment may also be made of a piezoelectric single crystal stack or other ferroelectric materials and antiferroelectric materials.

[0061] In this embodiment, the convex curved beam 1, the concave curved beam 2 and the square side wall may be made of stainless steel or titanium alloy in addition to aluminum alloy.

[0062] The concave-convex beam type low-frequency directional flextensional transducer in this embodiment is driven by only a single electrical signal during operation, and there is no need to adjust the signal amplitude weighting coefficient and phase parameter with frequency.

[0063] Example 2

[0064] Same as Example 1, except that:

[0065] Combination Figure 3 In this embodiment, the thickness of the convex curved beam 1 is less than the thickness of the concave curved beam 2. At this time, the monopole mode radiation component of the transducer increases, the broadband emission effect of the transducer is better, and the spatial uniformity of the radiated sound field in the yz plane is higher.

[0066] Example 3

[0067] Same as Example 1, except that:

[0068] Combination Figure 4 In this embodiment, both the convex curved beam 1 and the concave curved beam 2 are double-section structures. Compared with a single-section structure, the transducer can reduce the resonant frequency at the same size or increase the power capacity at the same resonant frequency, and increase the control means for the formation of low-frequency directivity.

[0069] Example 3

[0070] Same as Example 1, except that:

[0071] Combination Figure 5 The vibrator assembly in this embodiment adopts magnetostrictive material, including at least one magnetostrictive rod 4, a permanent magnet sheet 5 and an excitation coil 6; wherein the magnetostrictive rod 4 is arranged along the height direction, and when there are multiple magnetostrictive rods 4, the multiple magnetostrictive rods 4 are arranged along the height direction; the top and bottom of the magnetostrictive rod 4 are connected to the permanent magnet sheet 5; the excitation coil 6 is wound around the side wall of the magnetostrictive rod 4; when the excitation coil 6 is energized, the magnetic field generated acts on the magnetostrictive rod 4, causing the length of the magnetostrictive rod 4 to change; the permanent magnet sheet 5 ensures the deformation degree of the magnetostrictive rod 4 by enhancing and stabilizing the magnetic field, thereby realizing the vibration of the vibrator. Preferably, the magnetostrictive material is terbium dysprosium iron or iron gallium; the high magnetic energy product material is an alloy permanent magnet material such as neodymium iron boron, aluminum nickel cobalt, samarium cobalt, or a ferrite permanent magnet material.

[0072] The radiation housing in this embodiment may adopt the housing structure in Embodiment 1, 2 or 3.

[0073] Combination Figure 8 , which is a transmission voltage response curve diagram of the concave direction and the convex direction of the present invention. Between the first-order resonance peak and the second-order resonance peak, the response of the concave direction is greater than the response of the convex direction, and at a certain frequency point in the middle, the response difference between the concave and convex surfaces reaches the maximum, realizing cardioid directional transmission.

[0074] Finally, it should be noted that the above embodiments are only for illustrating the technical solutions of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A concave-convex beam type low-frequency directional flextensional transducer, characterized in that: include: An outwardly convex curved beam (1), an inwardly concave curved beam (2), a top wall, a bottom wall and a vibrator assembly (3); wherein: The convex curved beam (1), the concave curved beam (2), the top wall and the bottom wall are continuous solid structures. The convex curved beam (1) and the concave curved beam (2) are arranged opposite to each other and have the same height. The tops of the two are respectively connected to the top wall, and the bottoms of the two are respectively connected to the bottom wall, so as to form an asymmetric radiation shell together; wherein: The vibrator assembly (3) comprises one or more sets of driving vibrators arranged in parallel and evenly, and the driving vibrators are connected inside the radiation shell along the height direction of the transducer; The convex curved beam (1) is vertically arranged along the height direction, and has at least one convex surface with a curvature protruding from the radiation shell toward the outside, and the center line of the convex surface is perpendicular to the height direction; The inwardly concave curved beam (2) is vertically arranged along the height direction, and has a concave surface with a curvature that is recessed from the outside into the radiation shell, and the center line of the concave surface is perpendicular to the height direction; The thickness or curvature radius of the convex surface of the outward convex curved beam (1) and the concave surface of the inward concave curved beam (2) are different, so that the modal radiation component proportion and coupling strength of the transducer can be adjusted by adjusting the thickness or curvature radius of the convex surface and / or the concave surface.

2. The concave-convex beam type low-frequency directional flextensional transducer according to claim 1, characterized in that: The radiation housing has a first side surface, a second side surface, a third side surface and a fourth side surface, and the projection of the first side surface, the second side surface, the third side surface and the fourth side surface on the bottom wall after being surrounded is a rectangle; The convex curved beam (1) is located on the first side surface, and the concave curved beam (2) is located on the third side surface; the second side surface and the fourth side surface are hollowed out; The projection shape of the outward convex curved beam (1) on the third side surface is a rectangle, and the projection shape on the second side surface is one or more continuous arcs; The projection shape of the inwardly concave curved beam (2) on the first side surface is a rectangle, and the projection shape on the second side surface is one or more continuous arcs; The number of convex surfaces of the outwardly convex curved beam (1) is the same as the number of concave surfaces of the inwardly concave curved beam (2); The thickness of the convex surface is less than or equal to the thickness of the concave surface.

3. The concave-convex beam type low-frequency directional flextensional transducer according to claim 1, characterized in that: The convex curved beam (1) has two continuous convex surfaces protruding from the radiation shell toward the outside; the concave curved beam (2) has two continuous concave surfaces recessed from the outside toward the inside of the radiation shell.

4. The concave-convex beam type low-frequency directional flextensional transducer according to any one of claims 1 to 3, characterized in that: The materials used to make the outwardly convex curved beam (1) and the inwardly concave curved beam (2) are aluminum alloy, stainless steel or titanium alloy.

5. The concave-convex beam type low-frequency directional flextensional transducer according to any one of claims 1 to 3, characterized in that: The vibrator assembly (3) is a piezoelectric ceramic stack; the piezoelectric ceramic stack is formed by bonding an even number of piezoelectric ceramic sheets; the piezoelectric ceramic sheets are polarized along the thickness direction, and the polarization directions of two adjacent piezoelectric ceramic sheets are opposite. An electrode sheet is also arranged between every two piezoelectric ceramic sheets, and all the piezoelectric ceramic sheets are electrically connected in parallel.

6. The concave-convex beam type low-frequency directional flextensional transducer according to any one of claims 1 to 3, characterized in that: The vibrator assembly (3) is a piezoelectric single crystal stack; the piezoelectric single crystal stack is formed by bonding an even number of piezoelectric single crystal pieces; an electrode sheet is arranged between every two piezoelectric single crystal pieces, and all the piezoelectric single crystal pieces are electrically connected in parallel.

7. The concave-convex beam type low-frequency directional flextensional transducer according to any one of claims 1 to 3, characterized in that: The vibrator assembly (3) comprises: at least one magnetostrictive rod (4), a permanent magnetic sheet (5) and an excitation coil (6); wherein the magnetostrictive rod (4) is arranged in the height direction, and when there are a plurality of magnetostrictive rods (4), the plurality of magnetostrictive rods (4) are arranged in the height direction; the top and bottom of the magnetostrictive rod (4) are both connected to the permanent magnetic sheet (5); the excitation coil (6) is wound around the side wall of the magnetostrictive rod (4); when the excitation coil (6) is energized, the magnetic field generated acts on the magnetostrictive rod (4), causing the length of the magnetostrictive rod (4) to change; the permanent magnetic sheet (5) ensures the deformation degree of the magnetostrictive rod (4) by enhancing and stabilizing the magnetic field, thereby realizing the vibration of the vibrator.

8. The concave-convex beam type low-frequency directional flextensional transducer according to claim 7, characterized in that: The magnetostrictive rod (4) is made of magnetostrictive material, and the permanent magnetic sheet (5) is made of high magnetic energy product material.

9. The concave-convex beam type low-frequency directional flextensional transducer according to any one of claims 1 to 3, characterized in that: The flextensional transducer is driven by a single-channel electrical signal during operation, so that the signal amplitude weighting coefficient and phase parameter do not need to be adjusted with frequency changes.

10. The concave-convex beam type low-frequency directional flextensional transducer according to any one of claims 1 to 3, characterized in that: The height of the vibrator assembly (3) is greater than the height of the inner wall of the radiation shell. When the vibrator assembly (3) is installed inside the radiation shell, the radiation shell is deformed, so that the vibrator assembly (3) is fixed inside the radiation shell by utilizing the pressure generated by the increased height of the inner wall of the radiation shell, thereby applying an axial pre-tightening force to the vibrator assembly (3).

Images