Self-supporting deepwater transducer based on relaxor ferroelectric single crystal

Abstract

The utility model discloses a self-supporting deepwater transducer based on relaxor ferroelectric single crystal, which comprises a certain number of transducer units, and each transducer unit comprises a piezoelectric element, a transition block, a bending shell, a force transmission plate and a radiation panel, the piezoelectric element adopts a relaxor ferroelectric single crystal element; the bending shell is in a VII type flextensional transducer shell form with a long shaft and a short shaft vibrating in the same phase, a force transmission plate is additionally arranged on the outer side of the short shaft of the shell, a certain number of transducer units are arranged according to a certain rule, and the two ends of the transducer units are connected with radiation panels through the force transmission plates. Transverse vibration of the single-crystal element is subjected to displacement amplification on the short axis of the shell through the bent shell, the force transmission plate transmits the vibration to the radiation panel, and the radiation panel is used for reducing the working frequency, unifying the vibration phase of the transducer unit, directly facing fluid to bear hydrostatic pressure and isolating the internal space from the external fluid. The static pressure of external fluid acts on the radiation panel and acts on the shell short shaft through the force transmission plate.

Description

Technical Field

[0001] The utility model belongs to the technical field of underwater electronic equipment, and in particular relates to a self-supporting deep-water transducer based on a relaxor ferroelectric single crystal. Background Art

[0002] The pressure-resistant structures of underwater acoustic transducers for deep-water operation mainly include self-supporting, compressed gas-filled, oil-filled and compliant tube-filled, oil-filled, and overflow-filled. Among them, the self-supporting structure is simple, but the working depth is shallow, usually not more than 300m, and the transducer performance varies greatly with the water depth. The representative transducer type is the air-backed flextensional transducer. Flextensional transducers are usually divided into seven categories, among which type IV flextensional transducers and type VII flextensional transducers are typical low-frequency, high-power transmitting transducers. With the increase of hydrostatic pressure, the comprehensive force of the transducer shell causes the prestress of the air-backed type IV flextensional transducer to gradually decrease, the transducer performance decreases, and the working depth depends on the size of the prestress; while the prestress of the air-backed type VII flextensional transducer gradually decreases, and the working depth depends on the mechanical strength of the structure.

[0003] An effective technical approach to improve the transmission power of underwater acoustic transducers is to use active materials with excellent performance. Relaxor ferroelectric single crystals have better piezoelectric and dielectric properties than piezoelectric ceramics. Due to the anisotropic characteristics of relaxor ferroelectric single crystal materials, they exhibit different characteristics and application directions along different polarization directions. c Directionally polarized relaxor ferroelectric single crystal materials d 32 Compared with isotropic piezoelectric ceramics d 31 It is several times higher and exhibits superior piezoelectric properties in its lateral length direction, which can effectively improve the emission performance of the transducer. c The characteristics of the directional polarized relaxor ferroelectric single crystal material can be integrated with the air-backed type VII flextensional transducer structure to achieve greater water depth and higher power transmission.

[0004] The transducer with self-supporting structure is not able to withstand water depth, and the working depth is limited by the strength of mechanical structure and the size of prestress. For air-backed type IV flextensional transducer, as the hydrostatic pressure increases, the comprehensive force of the transducer shell causes the prestress of the air-backed type IV flextensional transducer to gradually decrease, and the transducer performance decreases. The performance of the transducer is affected by the active material. Piezoelectric materials are commonly used active materials for underwater acoustic transducers. A higher piezoelectric coefficient is conducive to improving the performance of the transducer. The piezoelectric coefficient of the new relaxor ferroelectric single crystal material is several times higher than that of traditional piezoelectric ceramics. Utility Model Content

[0005] In order to solve the defects and shortcomings of the above-mentioned prior art, the utility model provides a combination of c Based on the characteristics of the directionally polarized relaxor ferroelectric single crystal material, it is integrated with the air-backed type Ⅶ flexural tensional transducer structure to achieve the purpose of greater water depth and higher power transmission of the transducer. Compared with the use of piezoelectric ceramic elements, the piezoelectric coefficient is higher and the transducer can achieve a higher transmission response. Compared with the use of convex curved shells, it can apply prestress to the piezoelectric element and at the same time improve the transducer's ability to withstand hydrostatic pressure, thereby creating a self-supporting deep-water transducer based on relaxor ferroelectric single crystal.

[0006] The purpose of the utility model is achieved through the following technical solutions: a self-supporting deep-water transducer based on relaxor ferroelectric single crystal, comprising a certain number of transducer units, each of which comprises a piezoelectric element, a transition block, a curved shell, a force transmission plate and a radiation panel; the piezoelectric element adopts a method of c The invention discloses a relaxor ferroelectric single crystal element with polarization in the direction of the direction; the curved shell adopts the form of a Ⅶ-type flexural tension transducer shell in which the long axis and the short axis vibrate in phase, and a force transmission plate is added to the outside of the short axis of the shell respectively, and a certain number of transducer units are arranged in a certain rule, and the radiation panel is connected to the two ends of the transducer unit through the force transmission plate. The lateral vibration of the single crystal element is amplified by the displacement at the short axis of the shell through the curved shell, and the force transmission plate transmits the vibration to the radiation panel. The radiation panel is used to reduce the operating frequency and unify the vibration phase of the transducer unit. At the same time, it directly faces the fluid to bear the hydrostatic pressure and isolates the internal space from the external fluid; the static pressure of the external fluid acts on the radiation panel and acts on the short axis of the shell through the force transmission plate. The contraction of the short axis of the shell causes the long axis to contract at the same time. The pressure in the direction of the long axis of the shell acts on the piezoelectric element through the transition block. As the hydrostatic pressure increases, the pressure on the element, that is, the prestress, increases. Under the condition of ensuring the mechanical strength of the piezoelectric element and the passive structure, the working depth of the transducer is improved.

[0007] Preferably, the piezoelectric element is a rectangular parallelepiped structure, the length and width of the rectangular parallelepiped are much greater than its thickness; the piezoelectric element is made of a new relaxor ferroelectric single crystal material, and the single crystal element is along

[011] c Directional polarization; piezoelectric constant corresponding to polarization along the width direction d 32 It is a negative value, and the piezoelectric constant corresponding to polarization along the length direction is d 31 is a positive value, and d 32 Absolute value greater than d 31 .

[0008] Preferably, the curved shell is a tensile body with a concave structure, which consists of three parts, namely an end block structure, a hypotenuse structure and a platform structure; the shell thickness of the curved shell in the long axis direction is greater than the shell thickness in the short axis direction.

[0009] Preferably, the overall shape of the end block structure is a rectangular parallelepiped, which is connected to the transition block and the bevel structure, wherein the length of the end block structure is the same as the length of the piezoelectric element, the width is equal to the sum of the thickness of the piezoelectric element, the height of the inner cavity of the curved shell, and the height of the bevel structure, and the thickness is greater than the thickness of the platform structure; the bevel structure is a parallelogram-shaped stretching body, the length of which is the same as the length of the piezoelectric element, inclined from the edge of the end block structure to the element, and the thickness is the same as the thickness of the platform structure; the platform structure is a rectangular parallelepiped, the length of which is the same as the length of the piezoelectric element, the width is less than the length of the piezoelectric element, the thickness is the same as the bevel structure, and is less than the thickness of the end block structure.

[0010] Preferably, the force transfer plate is a rectangular parallelepiped structure, with a length the same as that of the piezoelectric element, a width greater than that of the end block structure, and a thickness less than that of the platform structure.

[0011] Preferably, all transducer units are arranged at equal intervals along the length and width directions of the transducer; the spacing between units in the length direction of the transducer is equal to the sum of the transducer unit length and the gap, and the spacing between units in the width direction of the transducer is equal to the sum of the transducer unit width and the gap; the gap in the length direction of the transducer unit is equal to the gap in the width direction of the transducer unit.

[0012] Preferably, there are two radiation panels, which are located on both sides of the transducer unit respectively. The length of the radiation panel is greater than the length of all the transducer units arranged evenly spaced, the width of the radiation panel is greater than the width of all the transducer units arranged evenly spaced, and the thickness of the radiation panel is much smaller than its length and width.

[0013] Preferably, the length, width and thickness of the piezoelectric element are 20mm*17mm*2mm respectively.

[0014] Preferably, the transition block is made of aluminum alloy, and the curved shell, force transfer plate and radiation panel are made of TC4 titanium alloy.

[0015] Preferably, the length of the force transmission plate is equal to the tensile length of the curved shell.

[0016] The beneficial effects of the utility model are:

[0017] Compared with the piezoelectric ceramic element, the utility model has a higher piezoelectric coefficient and the transducer can achieve a higher emission response; compared with the convex curved shell, the utility model can apply prestress to the piezoelectric element and improve the hydrostatic pressure resistance of the transducer. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A three-dimensional schematic diagram of a curved structure transducer unit using a relaxor ferroelectric single crystal cuboid element in one embodiment of the utility model;

[0019] Figure 2 This is a front view of a curved structure transducer unit using a relaxor ferroelectric single crystal cuboid element in one embodiment of the utility model;

[0020] Figure 3 This is a schematic diagram of the arrangement of 25 transducer units in one embodiment of the utility model;

[0021] Figure 4 This is an overall schematic diagram of a transducer with a radiation panel added in one embodiment of the utility model;

[0022] Figure 5 This is a front view of a transducer unit with a radiation panel in one embodiment of the utility model;

[0023] Figure 6 This is a front view of the displacement change of the radiation panel of the transducer unit under the normal force in one embodiment of the utility model;

[0024] Figure 7 It is a finite element simulation curve of the emission voltage response of the transducer in three directions in water in one embodiment of the utility model;

[0025] Figure 8 It is a finite element simulation curve of the directivity of the transducer in three planes in water in one embodiment of the utility model;

[0026] 1- piezoelectric element, 2- transition block, 3- force transmission plate, 4- bending shell, 5- radiation panel, A- end block structure, B- bevel structure, C- platform structure. DETAILED DESCRIPTION

[0027] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of the present invention.

[0028] A self-supporting deep-water transducer based on a relaxor ferroelectric single crystal in the embodiment provided by the utility model is as follows: Figure 4 As shown, the transducer includes two radiation panels, 25 transducer units, and each transducer unit includes a piezoelectric element, two transition blocks, a bending shell, and two force transmission plates.

[0029] In this embodiment, the length, width and height dimensions of the transducer are 162 mm*105 mm*17.8 mm respectively, and the length, width and height directions of the transducer are the same as the width, length and thickness directions of the piezoelectric element.

[0030] like Figure 1 and 2 As shown, the piezoelectric single crystal element in this embodiment is a rectangular parallelepiped, and the length and width are much larger than the thickness, and the length, width and thickness are 20mm*17mm*2mm respectively; the piezoelectric element is made of a new relaxor ferroelectric single crystal material PIN-46%PMN-30%PT, and the single crystal element is along

[011] c Directional polarization; the two planes of the length and width of the piezoelectric element are used as the positive and negative electrode planes respectively; d 32 The direction is the same as the width direction of the piezoelectric element. d 31 The direction is the same as the length direction of the piezoelectric element. d 33 The direction is the same as the thickness direction of the piezoelectric element; d 32 is -1693pC / N, d 31 675pC / N, d 33 It is 1068pC / N.

[0031] The transition block in this embodiment is a rectangular parallelepiped made of aluminum alloy; the length of the transition block is the same as the length of the piezoelectric element, the thickness is the same as the thickness of the piezoelectric element, and the width is much smaller than the length, and the length, width and thickness are 20mm*4mm*2mm respectively.

[0032] The bending shell and the force transmission plate in this embodiment are processed by an integrated molding machine, and the material is TC4 titanium alloy; the bending shell is a stretched body, and the stretched length is the same as the length of the piezoelectric element; Figure 2 It can be seen from the main view that the curved shell is composed of three structures, namely the end block structure A, the bevel structure B and the platform structure C; the overall shape of the end block structure is a rectangular parallelepiped, with a length, width and thickness of 20mm*12.8mm*3.2mm respectively, and it is connected to the transition block and the bevel structure. The length of the end block structure is the same as the length of the piezoelectric element, and the width is equal to the sum of the thickness of the piezoelectric element, the height of the inner cavity of the shell, and the height of the bevel structure, and the thickness is greater than the thickness of the platform structure; the bevel structure is a parallelogram-shaped stretching body, with the same length as the length of the piezoelectric element, inclined from the edge of the end block structure to the element, and the same thickness as the platform structure; the platform structure is a rectangular parallelepiped, with a length, width and thickness of 20mm*5mm*2.4mm respectively, the same length as the length of the piezoelectric element, the width is less than the length of the piezoelectric element, the same thickness as the bevel structure, and less than the thickness of the end block structure.

[0033] The force transfer plate in this embodiment is a rectangular parallelepiped with a length, width and thickness of 20mm*4.5mm*2mm respectively. The length is the same as the length of the piezoelectric element, the width is higher than the end block structure, and the thickness is less than the width of the platform structure.

[0034] Figure 3 : is a schematic diagram of the arrangement of 25 identical transducer units in this embodiment. All transducer units are arranged in 5 rows and 5 columns at equal intervals along the length direction and width direction of the unit; the spacing between units in the length direction of the transducer is equal to the sum of the length of the transducer unit and the gap, and the spacing between units in the width direction of the transducer is equal to the sum of the width of the transducer unit and the gap; the gap in the length direction of the transducer unit is equal to the gap in the width direction of the transducer unit; and the gap is 2 mm.

[0035] Figure 4 This is the overall schematic diagram of the transducer with a radiation panel added in this embodiment. The transducer includes two radiation panels, which have the same structure, size, and material, and are located on both sides of the 25 transducer units; the radiation panel is a rectangular parallelepiped, with a length, width, and thickness of 162mm*105mm*2.4mm, and is made of TC4 titanium alloy; the length of the radiation panel is greater than the length of all transducer units arranged at equal intervals, the width of the radiation panel is greater than the width of all transducer units arranged at equal intervals, and the thickness of the radiation panel is much smaller than the length and width.

[0036] In this embodiment, the lateral vibration of the single crystal element is amplified by the displacement of the short axis through the bending shell, and the force transfer plate transmits the vibration to the radiation panel. The addition of the radiation panel can reduce the operating frequency and unify the vibration phase of the transducer unit, and can directly face the fluid to bear the hydrostatic pressure, thereby isolating the internal space from the external fluid.

[0037] Figure 5 It is a front view of a transducer unit with a radiation panel in this embodiment, a fixed constraint condition is applied to the radiation panel on one side, and a normal plane load is applied to the outer surface of the radiation panel on the other side to simulate hydrostatic pressure; Figure 6 The displacement change is generated. The transducer bending shell shrinks in the short axis direction and the long axis direction. The lateral pressure is generated on the piezoelectric element through the transition block. As the hydrostatic pressure increases, the pressure on the element, that is, the prestress, increases. Under the condition of ensuring the safe mechanical strength of the piezoelectric element and the passive structure, the working depth of the transducer can be increased.

[0038] Figure 7 This is the finite element simulation curve of the emission voltage response of the transducer in three directions in water in this embodiment, the resonant frequency is 3kHz, the maximum emission voltage response is 117dB, the -3dB bandwidth is about 1.3kHz, and the Q value is 2.3.

[0039] Figure 8: is the finite element simulation curve of the directivity of the transducer in three planes in water in this embodiment. It can be seen that the transducer is non-directional.

[0040] In summary, the self-supporting deep-water transducer based on relaxor ferroelectric single crystal provided by the utility model has a higher piezoelectric coefficient than piezoelectric ceramic elements, and the transducer can achieve a higher emission response; compared with the convex curved shell, this embodiment can apply prestress to the piezoelectric element and improve the hydrostatic pressure resistance of the transducer. It has important military application value for improving the detection capability of active sonar.

[0041] The present invention cites relevant papers by James F. Tressler, such as A comparison of the underwater acoustic performance of single crystal versus piezoelectricceramic-based "cymbal" projectors. J. Acoustic. Soc, Am. 119(2), 2006:879-889.

[0042] Explanation of the relevant technical terms in this utility model: Ternary relaxor ferroelectric single crystal PIN-PMN-PT (PIMNT, Pb(In 1 / 2 Nb 1 / 2 )O3-Pb(Mg 1 / 3 Nb 2 / 3 )O3-PbTiO3) is a solid solution of lead indium niobate, lead magnesium niobate and lead titanate.

[0043] The self-supporting form is a type of pressure-resistant structure for transducers, which relies on its own structural strength to resist the influence of hydrostatic pressure on the transducer. This type of pressure-resistant form is generally used by air-backed transducers. The advantage of this method is its simple structure, but its disadvantage is its shallow working depth and large changes in transducer performance.

[0044] Type IV flextensional transducers are composed of multiple short elliptical tubes. In each elliptical shell, an active material pile is inserted along the long axis. When the active material pile stretches and contracts, the elliptical tube is stimulated to do bending vibration. In order to enable broadband emission, the coupling of multiple vibration modes is often used. Its disadvantage is that as the depth of immersion in water continues to increase, the prestress on the active material pile will continue to decrease, reducing its radiation performance.

[0045] The structure of the Ⅶ-type flextensional transducer is similar to that of the Ⅳ-type flextensional transducer. The shell is obtained by stretching the bending plane. The cross section of the Ⅶ-type is large at both ends and small in the middle, shaped like a bone, so the Ⅶ-type flextensional transducer is also called a "dog bone" transducer. As the water depth increases, the prestress of the air-backed Ⅶ-type flextensional transducer gradually decreases, and the working depth depends on the mechanical strength of the structure.

[0046] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A self-supporting deep-water transducer based on relaxor ferroelectric single crystal, characterized in that: It contains a certain number of transducer units, each of which includes a piezoelectric element, a transition block, a curved shell, a force transmission plate and a radiation panel; the piezoelectric element adopts the method of [011] c The curved shell adopts the form of a Ⅶ-type flextensional transducer shell in which the long axis and the short axis vibrate in phase, and a force transmission plate is added to the outer side of the short axis of the shell respectively, and a certain number of transducer units are arranged in a certain rule, and the radiation panels are connected at both ends of the transducer units through the force transmission plates. The lateral vibration of the single crystal element is amplified by the displacement at the short axis of the shell through the curved shell, and the force transmission plate transmits the vibration to the radiation panel. The radiation panel is used to reduce the operating frequency and unify the vibration phase of the transducer unit. At the same time, it directly faces the fluid to bear the hydrostatic pressure and isolates the internal space from the external fluid. The static pressure of the external fluid acts on the radiation panel and acts on the short axis of the shell through the force transfer plate. The contraction of the short axis of the shell causes the long axis to contract at the same time. The pressure in the long axis direction of the shell acts on the piezoelectric element through the transition block. As the hydrostatic pressure increases, the pressure on the element, i.e. the prestress, increases. While ensuring the safe mechanical strength of the piezoelectric element and the passive structure, the working depth of the transducer is increased.

2. A self-supporting deep-water transducer based on relaxor ferroelectric single crystal according to claim 1, characterized in that: The piezoelectric element is a rectangular parallelepiped structure, the length and width of the rectangular parallelepiped are much greater than its thickness; the piezoelectric element is made of a new relaxor ferroelectric single crystal material, and the single crystal element is along [011] c Directional polarization; the piezoelectric constant d corresponding to polarization along the width direction 32 It is a negative value, and the piezoelectric constant d corresponding to polarization along the length direction 31 is positive, and d 32 The absolute value is greater than d 31 .

3. A self-supporting deep-water transducer based on relaxor ferroelectric single crystal according to claim 2, characterized in that: The curved shell is a tensile body with a concave structure, which consists of three parts, namely an end block structure, a hypotenuse structure and a platform structure; the shell thickness of the curved shell in the long axis direction is greater than the shell thickness in the short axis direction.

4. A self-supporting deep-water transducer based on relaxor ferroelectric single crystal according to claim 3, characterized in that: The end block structure has an overall shape of a rectangular parallelepiped, which is connected to the transition block and the bevel structure, wherein the length of the end block structure is the same as the length of the piezoelectric element, the width is equal to the sum of the thickness of the piezoelectric element, the height of the cavity inside the curved shell, and the height of the bevel structure, and the thickness is greater than the thickness of the platform structure; the bevel structure is a parallelogram-shaped stretching body, the length of which is the same as the length of the piezoelectric element, inclined from the edge of the end block structure to the element, and the thickness is the same as the thickness of the platform structure; the platform structure is a rectangular parallelepiped, the length of which is the same as the length of the piezoelectric element, the width is less than the length of the piezoelectric element, the thickness is the same as the bevel structure, and is less than the thickness of the end block structure.

5. A self-supporting deep-water transducer based on relaxor ferroelectric single crystal according to claim 3, characterized in that: The force transmission plate is a rectangular parallelepiped structure, with a length the same as that of the piezoelectric element, a width greater than that of the end block structure, and a thickness less than that of the platform structure.

6. A self-supporting deep-water transducer based on relaxor ferroelectric single crystal according to claim 3, characterized in that: All transducer units are arranged at equal intervals along the length and width directions of the transducer; the spacing between units in the length direction of the transducer is equal to the sum of the transducer unit length and the gap, and the spacing between units in the width direction of the transducer is equal to the sum of the transducer unit width and the gap; the gap in the length direction of the transducer unit is equal to the gap in the width direction of the transducer unit.

7. A self-supporting deep-water transducer based on relaxor ferroelectric single crystal according to claim 3, characterized in that: There are two radiation panels, which are located on both sides of the transducer unit respectively. The length of the radiation panel is greater than the length of all the transducer units arranged evenly spaced, the width of the radiation panel is greater than the width of all the transducer units arranged evenly spaced, and the thickness of the radiation panel is much smaller than its length and width.

8. The self-supporting deep-water transducer based on relaxor ferroelectric single crystal according to claim 2, characterized in that: The length, width and thickness of the piezoelectric element are 20mm*17mm*2mm respectively.

9. A self-supporting deep-water transducer based on relaxor ferroelectric single crystal according to claim 1, characterized in that: The transition block is made of aluminum alloy, and the curved shell, force transmission plate and radiation panel are made of TC4 titanium alloy.

10. The self-supporting deep-water transducer based on relaxor ferroelectric single crystal according to claim 5, characterized in that: The length of the force transmission plate is equal to the tensile length of the bending shell.

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