A medium frequency high energy density conical surface magnetostrictive electro-acoustic transducer array structure

Abstract

The application discloses a kind of medium-frequency high-energy-density conic surface giant magnetostrictive electroacoustic transducer array structure, including a four-way cubic base and four medium-frequency conic surface transducer units, each unit contains double conic surface transducer shell, super magnetostrictive drive module, AC excitation coil and sealing fixed structure.Four double conic surface transducer shells are fixed on the four sides in the same circumferential direction of four-way cubic base by bolt respectively, four units are in phase vibration, realize the energy conversion of electric-magnetic-mechanical-acoustic, and produce the sound field superposition effect in the direction perpendicular to circumferential direction (main shaft direction), realize 221.5dB high sound source level sound wave energy output, the application also combines conic array structure, and the structure parameters are optimized by MSDOA algorithm.The application compared with prior art, in the same sound source level, directivity case, volume weight is reduced more than one time.

Description

Technical Field

[0001] This invention belongs to the field of electroacoustic transducer technology, specifically relating to a mid-frequency high-energy-density conical supermagnetostrictive electroacoustic transducer array structure. Background Technology

[0002] The core functional materials of current electroacoustic transducers mainly include giant magnetostrictive materials and piezoelectric ceramic materials. Giant magnetostrictive materials, represented by Terfenol-D, have advantages such as high energy density at room temperature, large magnetomechanical coupling coefficient, large strain, low sound velocity and small Young's modulus, which are very beneficial for electroacoustic transducers to achieve low frequency domain, miniaturization and high power output.

[0003] Developing electroacoustic transducers with high energy density, mid-to-low frequency, and wide bandwidth has always been a technical challenge in this field. Giant magnetostrictive transducers utilize alternating current to drive coils, generating an alternating magnetic field that causes the giant magnetostrictive material to periodically expand and contract, thereby inducing mechanical vibration and radiating sound waves into the water through the shell, completing the "electro-magnetic-mechanical-acoustic" energy conversion. In the propagation of underwater acoustic signals from hundreds to thousands of hertz, diffusion attenuation is the main source of propagation loss; as the frequency increases, the attenuation caused by seawater absorption increases significantly—for example, the loss of a 100kHz sound wave propagating 1km underwater can reach 95dB. Therefore, developing mid-to-low frequency transducers is crucial for achieving long-distance underwater acoustic communication and detection. However, according to physical laws, the radiated acoustic power of a transducer is usually proportional to the volume and size of the vibrating radiator, leading to an inherent contradiction between the requirements for high sound source level and miniaturization. To address this challenge, existing technologies mostly seek breakthroughs through new materials and structural designs. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a mid-frequency, high-energy-density conical supermagnetic-strictive electroacoustic transducer array structure.

[0005] The objective of this invention is achieved through the following technical solution: A mid-frequency high-energy-density conical super magnetostrictive electroacoustic transducer array structure includes a four-way cubic base, with the direction of the line connecting the front and rear centers of the four-way cubic base being the main axis direction; each of the four sides of the four-way cubic base is fixed with a conical transducer unit of the same structure and size, and the opposite conical transducer units are symmetrically arranged relative to the main axis. The conical transducer unit includes a conical shell 1 located outside the four-way cubic base and a conical shell 2 inserted inside the four-way cubic base. The outer surface of the conical shell 1 forms a radiating surface. The conical shell 1 and the conical shell 2 are fixedly connected. A magnetic upper base is installed inside the conical shell 1, and a magnetic lower base is installed inside the conical shell 2. Two parallel magnetostrictive oscillators are first glued and fixed between the magnetic upper base and the magnetic lower base. An AC excitation coil is wrapped around the magnetostrictive oscillator. The magnetostrictive oscillator is formed by alternately bonding permanent magnets and magnetostrictive rods, and both ends of the oscillator are permanent magnets. The magnetic upper base and the magnetic lower base apply preload pressure to both ends of the oscillator. Adjacent permanent magnets in the magnetostrictive oscillator are placed with their same poles facing each other. In the two parallel magnetostrictive oscillators, one has its N pole facing upward and the other has its S pole facing upward. The input current amplitude and phase of the AC excitation coils of the four conical transducer units are the same, and the winding direction is consistent.

[0006] As a further improvement, multiple lifting rings are fixed to each of the four sides of the four-way cubic base, and a watertight head is installed at the rear of the four-way cubic base.

[0007] In a further improvement, the super magnetostrictive oscillator is composed of four super magnetostrictive rods and five permanent magnets arranged and bonded alternately; the length of the AC excitation coil is less than the length of the super magnetostrictive oscillator.

[0008] In a further improvement, the length ratio of the permanent magnet to the super magnetostrictive rod is 0.16–0.25; both the permanent magnet and the super magnetostrictive rod have their surfaces slit.

[0009] In a further improvement, the permanent magnet is 8mm long and the giant magnetostrictive rod is 45mm long; the length of the AC excitation coil is less than the length of one permanent magnet of the giant magnetostrictive oscillator.

[0010] Further improvements include the following: both the upper and lower magnetically conductive bases are made of DT4C electrical pure iron material; the permanent magnets are made of neodymium iron boron material; the permanent magnets and the super magnetostrictive rods are bonded and fixed with adhesive, specifically EPO-TEKH74 series epoxy resin; the four-way cubic base is made of titanium alloy or aluminum alloy; and the watertight head is powered by the AC excitation coils of four conical transducer units, with the eight AC excitation coils connected in parallel.

[0011] A further improvement is made to the four-way cubic base, which has an installation cavity that mates with the conical shell two. The bottom of the installation cavity is connected to the conical shell two via a quick-locking mechanism. The quick-locking mechanism includes a male insertion ring fixed to the bottom of the conical shell two and a female insertion ring fixed to the bottom of the installation cavity. An inverted L-shaped groove is formed on the outer surface of the bottom of the male insertion ring. A locking block that mates with the inverted L-shaped groove is provided on the inner surface of the female insertion ring. The locking block is inserted into the L-shaped groove at the same time as the male insertion ring is inserted into the female insertion ring. The conical shell two and the four-way cubic base can be quickly engaged or disengaged by rotation.

[0012] In a further improvement, the conical shell one and conical shell two of the conical transducer unit are respectively fixed to the upper magnetic base and the lower magnetic base by positioning pins; the positioning pins are made of aluminum alloy; the length of the transducer oscillator is 0.2-0.8mm greater than the height of the transducer's internal cavity (depending on prestress requirements). A thin sheet is fixed to the outer periphery of the first conical shell. The thin sheet is fastened to the second conical shell and the four-way cubic base by fastening bolts. The fastening force of the fastening bolts provides mechanical prestress for the super magnetostrictive drive module. The mechanical prestress is superimposed with the stress introduced by the working water depth to form the total prestress. The total prestress is adjusted so that the super magnetostrictive rod works in the linear region of magnetostriction and is located at the point where the slope of the strain-magnetic field strength curve is the maximum. Each mounting cavity of the four-way cubic base is machined with an annular sealing groove, and a sealing gasket is placed in the annular sealing groove. When the four-way cubic base is connected to the conical shell of the four conical transducer units, the sealing gasket is compressed under the tightening force of the fastening bolts, causing the sealing gasket to undergo elastic deformation and fill all micro-uneven areas, thereby forming a watertight barrier at the contact interface.

[0013] Further improvements include that when the cone angle of the conical shell is 100°–115°, the resonant frequency of the transducer array is in the range of 1–2kHz; and the resonant frequency of the transducer array increases with the increase of the cone angle. The dimensions of the conical transducer unit do not exceed Ф390mm*300mm; the dimensions of the four-way cubic base do not exceed 500mm*500mm*500mm; the dimensions of the mid-frequency high-energy-density conical magnetostrictive electroacoustic transducer array do not exceed 730mm*730mm*570mm; the first and second conical shells are made of aluminum alloy; the sealed inner cavity of the conical transducer unit is filled with air or silicone oil.

[0014] Further improvements employ a multi-strategy decomposition optimization algorithm to optimize the parameters of the electroacoustic transducer array structure. The optimization objectives are the resonant frequency, the source level size SL, and the corresponding bandwidth BW, both of which are obtained through COMSOL finite element simulation. The constraint function is the resonant frequency, which is obtained through... Constraints are imposed, among which This is the resonant frequency in this finite element simulation. This is the target resonant frequency value, taken as 1250Hz in this optimization. Tolerance is the tolerance level for resonant frequency deviation. season and ; The parameters of the electroacoustic transducer array structure include the diameter of the top of the cone, the diameter of the bottom of the cone, the width of the sheet, the thickness of the shell, the thickness of the end face, the thickness of the four sides, the length of the four sides, and the thickness of the magnetic base. The multi-strategy decomposition optimization algorithm performs a global search in the first 60% of the iterations. The global search phase includes four parallel search strategies: The first is the extended search strategy, which combines historical best solutions, population average position and random perturbation to explore a wide range of areas, aiming to quickly locate potential high-quality solution regions. The strategy expression is as follows: ; in, It is the historical best solution in the current population. It is the current iteration number. It is the total number of iterations. It is the average position of the current population. It is a random number in the range [0,1]. and These are the upper and lower bounds of the search space. These are adaptive parameters that decrease with increasing iteration count, designed to quickly scan the entire search space and locate potential high-quality regions. This represents the search function corresponding to the first strategy; The second approach is a stochastic search strategy based on Lévy flight. By introducing a stochastic step size that follows a Lévy distribution, it balances global exploration with local exploitation and effectively avoids getting trapped in local optima. The strategy expression is as follows: ; Levy(D) is the Levy flight function, which generates random step sizes that follow a Levy distribution. It is a randomly selected individual that, through Levi's flight, effectively balances exploration and development; its random large step size allows it to escape local optima. This represents the search function corresponding to the second strategy; The third approach is a targeted development strategy, which relies on historical best solutions and population distribution guidance to fine-tune parameters in the neighborhood of high-quality solutions in order to improve the quality of solutions. The strategy expression is as follows: ; in These are adaptive parameters that control the development intensity. The targeted development strategy focuses on fine-tuning parameters in high-quality areas to improve the quality of the solution. This represents the search function corresponding to the third strategy; The fourth strategy is the balanced search strategy, which enhances convergence accuracy while maintaining search diversity by adjusting the mass function and motion parameters. The strategy expression is as follows; ; QF is the mass function used for equilibrium search; G1 and G2 are motion parameters that are adjusted with iteration parameters. and Introducing randomness and Lévy perturbation, Make fine adjustments; This represents the search function corresponding to the fourth strategy; In the last 40% of iterations of the multi-strategy decomposition optimization algorithm, a Chebyshev scalarization function is used to perform local multi-objective search optimization. The function expression is as follows: ; This represents a transducer design scheme; Representing the The weight vector of each sub-problem This represents different preferences for sound source level and bandwidth, and ; Or 2; , This represents the optimal value for the sound source level. Indicates the optimal bandwidth value; records the currently found sound source level respectively. and bandwidth The optimal value; by finding a solution that makes the source level and bandwidth With the ideal point The deviation is minimized to obtain a set of uniformly distributed Pareto optimal solutions, from which the best combination of structural parameters is selected.

[0015] The beneficial effects of this invention are as follows: 1) The conical transducer of the present invention adopts a conical structure, and its impedance curve changes slowly near the resonance point, resulting in a wider bandwidth.

[0016] 2) The volume of the conical transducer unit of this invention is ≤0.013m³, the weight is ≤20kg, the maximum size is ≤Ф390mm*300mm, the array volume is ≤0.14m³, the weight is ≤200kg, the maximum size is ≤730mm*730mm*570mm, and the size is small.

[0017] 3) This invention uses four conical transducer units to form a circumferentially symmetrical array. The four conical transducer units achieve constructive interference of sound waves in the main axis direction, with a sound source level of up to 221dB, which far exceeds the performance of a single unit (about 210dB). 4) This invention sacrifices the directivity in all four directions in exchange for a significant improvement in the sound source level in the main axis direction, thereby achieving high energy density output. Compared with existing transducer arrays with the same sound source level and directivity, the volume and weight are reduced by half. Attached Figure Description

[0018] The invention will be further illustrated with reference to the accompanying drawings, but the contents of the drawings do not constitute any limitation on the invention.

[0019] Figure 1A This is an overall structural diagram of a mid-frequency, high-energy-density conical supermagnetic-strict electroacoustic transducer array; Figure 1B This is an overall structural diagram of a conical supermagnetostrictive electroacoustic conical transducer unit; Figure 2 This is the overall assembly drawing of the mid-frequency high-energy-density conical supermagnetostrictive electroacoustic transducer array; Figure 3 This is the overall assembly drawing of the conical supermagnetostrictive electroacoustic conical transducer unit; Figure 4 This is a schematic diagram of the cam-hook structure between the conical supermagnetostrictive electroacoustic conical transducer unit and the four-way cubic base; Figure 5A This is a flowchart of the MSDOA optimization algorithm; Figure 5B This is a schematic diagram showing the geometric parameter names corresponding to the transducer; Figure 6A This is a diagram of the magnetic circuit structure during assembly in Example 1; Figure 6B This is the magnetic circuit diagram during assembly in Example 1; Figure 7 This is a schematic diagram of the circumferential directivity curve and the sound source level curve of the mid-frequency conical transducer unit; Figure 8 This is a schematic diagram of the directional curves and source level curves of a mid-frequency high-energy-density conical super magnetostrictive electroacoustic transducer array. Detailed Implementation

[0020] To make the purpose, technical solution, and advantages of the invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and examples. Example 1

[0021] Magnetic circuit structure such as Figure 4As shown, the super magnetostrictive rod 3 is made of Terfenol-D material, and a total of 32 rods are required (4 units × 4 rods / group × 2 groups / unit). The specific dimensions are: diameter 28mm and length 45.0mm. The surface of the rod is cut to reduce eddy current loss during operation.

[0022] The permanent magnet 4 uses N45SH neodymium iron boron material, and a total of 40 pieces are required (4 units × 5 pieces / group × 2 groups / unit). The specific dimensions are: diameter 28mm and height 8.0mm. It is also cut with slits to reduce losses.

[0023] The AC excitation coil 5 is wound with high-temperature resistant polyimide enameled wire, and the coil frame is made of nylon material with a temperature resistance rating of 180°C.

[0024] The overall conical transducer array diagram is attached. Figure 1A and Figure 2 As shown. The assembly drawing of the conical transducer unit is attached. Figure 1B and Figure 3 As shown. Conical shell 1 (6), conical shell 2 (7), and four-way cubic base 11 are all made of 7075-T6 high-strength aluminum alloy, precision machined after forging. The cone angle of the conical radial surface is 108°.

[0025] The upper and lower magnetic bases 1 and 2, as key components of the magnetic circuit, are made of DT4C electrical pure iron material, possessing high magnetic permeability (relative permeability > 5000) and high mechanical strength. Positioning pin holes are precisely machined on the bases to facilitate the positioning of the conical shell 6, the conical shell 7, and the super-magnetostrictive drive module, ensuring their relative stability.

[0026] The adhesive used is EPO-TEKH74 series high-strength, high-thermal-conductivity epoxy resin adhesive, which is used for bonding between the super magnetostrictive rod 3 and the permanent magnet 4.

[0027] The fastening bolt 8 is an M6×30 internal hexagonal stainless steel bolt, used to apply prestress and connect the conical shell 1 6, the conical shell 2 7, and the four-way cubic base 11.

[0028] The positioning pin is made of 316 stainless steel and is used to position and fix the super magnetostrictive drive module (including the vibrator, magnetic base and AC excitation coil) and the conical housing 6 and conical housing 7 components.

[0029] Oscillator bonding: Using a dedicated non-magnetic clamp, arrange and precisely align the four giant magnetostrictive rods 3 and five permanent magnets 4 in an alternating sequence of "permanent magnet-rod-permanent magnet-rod-permanent magnet-rod-permanent magnet-rod-permanent magnet". Ensure that adjacent permanent magnets are placed with their same poles facing each other. Apply epoxy resin evenly to the contact surfaces, apply clamping force, and then cure in an 80°C oven for 2 hours.

[0030] Two sets of oscillators and two magnetically conductive bases are assembled into a complete magnetic circuit structure. One set of rods has its N pole facing upwards, and the other set has its S pole facing upwards, forming an effective closed magnetic circuit. Positioning pins are inserted into both sides of the upper and lower magnetically conductive bases to fix them to conical shell one and conical shell two, ensuring that the oscillators will not rotate circumferentially and effectively preventing changes in the magnetic circuit caused by vibration during operation.

[0031] Install the conical housing 2.7, as shown in the attached figure. Figure 4 As shown, the cam 12 is integrated with the conical transducer housing 7, and the locking hook 14 is integrated with the four-way cubic base 11. The locking hook 14 is shown in the schematic diagram. The conical housing 7 is connected to the four-way cubic base 11 by rotating the quick-locking ring on the unit (about 60°), which drives the internal locking hook to engage with the latch on the side structure of the base.

[0032] Apply prestress: Connect conical shell 6 and conical shell 7 with 28 M6 bolts 8. Use a torque wrench to tighten the bolts gradually in three steps in a diagonal sequence. Since the length of the oscillator in its free state (including the permanent magnets at both ends) is slightly greater than the internal height of the shell, this tightening force provides axial prestress to the magnetostrictive drive module, making it work in the linear strain region with the maximum slope.

[0033] Four conical transducer units are integrated into an array to ensure their rigidity and acoustic properties.

[0034] The four assembled conical transducer units are connected and fastened to the four sides of the four-way cubic base through the bolt holes on their conical housings to complete their fixation.

[0035] Four stainless steel lifting rings 9 are installed on the four sides of the connecting base to lower the system to the working water depth and to steer the transducer, making it easier to control the direction of its main shaft to be the same as the direction of the detection target. The leads of the eight sets of AC excitation coils 5 are connected in parallel and then connected to a multi-core watertight connector (watertight head) 10, which is then potted with epoxy resin to ensure watertightness.

[0036] This invention utilizes 7075-T6 high-strength aluminum alloy and DT4C electrical pure iron material to ensure the mechanical strength and corrosion resistance of the conical surface, as well as the high magnetic permeability of the magnetically conductive base. The design of the conical radiating surface (108° cone angle) improves the working bandwidth, ensuring that the sound source level not only reduces the overall size but also facilitates installation and sealing.

[0037] This invention employs a magnetically conductive base and an interlaced permanent magnet layout to form a closed magnetic circuit, reducing magnetic leakage, ensuring the uniformity of the internal magnetic field of the giant magnetostrictive rod, and improving the magnetomechanical conversion efficiency. The slit treatment significantly reduces eddy current losses, and combined with epoxy potting, ensures high-temperature stability, making it suitable for long-term operation.

[0038] Example 2 The intermediate frequency conical transducer array was geometrically modeled using COMSOL finite element simulation software, where the output force of the rod was calculated based on the working water depth.

[0039] Solid Mechanics Module: Used to calculate the magnetostrictive strain, vibration response of conical surfaces, and prestress effect of supermagnetostrictive materials under magnetic field.

[0040] Pressure Acoustics Module: Used to calculate the radiation, propagation, and far-field sound pressure of underwater sound waves.

[0041] Based on the detailed dimensions of Example 1, a fully parametric 3D model was accurately constructed in COMSOL.

[0042] The geometric modeling includes four conical transducer units. Each unit comprises a conical shell I (radiating surface), a conical shell II, an internal oscillator assembly (each group consists of four Terfenol-D rods and five permanent magnets arranged alternately, with two groups per unit), an AC excitation coil, and a magnetically conductive base. Conical shell II simulates a four-way cubic base using fixed constraints. The lifting rings and watertight heads are omitted in this simulation to simplify calculations due to their minimal impact on acoustic performance.

[0043] The material parameters are defined, including the super magnetostrictive material, permanent magnet, aluminum alloy, water, and the enclosed gas in the enclosed space, which in this embodiment is air.

[0044] The pressure acoustic module selects the external water area and its external field calculation boundary.

[0045] Four conical transducer units (excluding the internal enclosed gas) are selected in the solid mechanics module area, and the output force of the giant magnetostrictive rod on the conical surface is set under the working environment.

[0046] Choose the acoustic-structure boundary in the multiphysics field, and select the contact part between the water area and the transducer, that is, the cone surface (four radiation surfaces) of the four cone transducers.

[0047] By studying the selected frequency, the source level curve is calculated, which yields values ​​such as the resonant frequency, the source level at the resonant frequency, and the bandwidth.

[0048] Model a single conical transducer and compare the sound source level curves on the main axis for arrays and single transducers.

[0049] like Figure 5A and 5B As shown. The present invention obtained a sound source level of 206.6 dB around the cone transducer unit and a resonant frequency of 1310 Hz through COMSOL finite element simulation.

[0050] As attached Figure 6A and Figure 6BAs shown. This invention, through COMSOL finite element simulation, obtained a mid-frequency high energy density conical supermagnetostrictive electroacoustic transducer array sound source level of 221.5 dB and a resonant frequency of 1370 Hz.

[0051] Example 3 Based on the core geometric parameters described in Example 1, the structural parameters of the "medium-frequency high energy density conical super magnetostrictive electroacoustic transducer array" were analyzed by finite element simulation. The effects and variation laws of the cone top diameter (diameter of the outer top surface of the cone shell 1 (6)), cone bottom diameter (diameter of the inner bottom surface of the cone shell 1 (6)), sheet width, shell thickness (thickness of the non-connected part of the sheet and the cone shell 2), end face thickness, surrounding thickness (thickness of the connected part of the sheet and the cone shell 2), surrounding length (difference between the inner and outer diameters of the connected part of the sheet and the cone shell 2) and magnetic base thickness on the sound source level and bandwidth were analyzed.

[0052] The representative locations of the key geometric parameters of the transducer are shown in the attached figure. Figure 5B As shown. The cone has a top radius of 70mm, a bottom radius of 66mm, a transducer radius of 180mm, a sheet radius of 75mm, a base thickness of 16.5mm, a perimeter thickness of 25mm, an end face thickness of 40mm, and a perimeter length of 45mm.

[0053] For every 10mm increase in the radius of the cone top of a single cone transducer, the sound source level increases by approximately 0.7dB, while the bandwidth decreases by approximately 15Hz.

[0054] For every 10mm increase in the bottom radius of the conical transducer unit, the sound source level decreases by approximately 1dB, and the bandwidth decreases by approximately 9Hz.

[0055] For every 10mm increase in the width of the tapered transducer unit slab, the sound source level increases by approximately 0.3dB, while the bandwidth decreases by approximately 1Hz. For every 10mm increase in the thickness of the conical transducer unit end face, the sound source level decreases by approximately 0.2dB, and the bandwidth decreases by approximately 20Hz.

[0056] For every 10mm increase in the thickness around the conical transducer unit, the sound source level increases by approximately 0.3dB, while the bandwidth decreases by approximately 10Hz.

[0057] When optimizing the design, the above principles can be used for fine-tuning.

[0058] Example 4 As attached Figure 3As shown in Example 3, based on the variation law of sound source level and bandwidth, this example elaborates on the implementation of the Multi-Strategy Decomposition Optimization Algorithm (MSDOA) used in the "Mid-Frequency High Energy Density Conical Supermagnetic-Strict Electroacoustic Transducer Array" of the present invention. This algorithm is used to optimize the key geometric parameters of the transducer array, including but not limited to the diameter of the cone top, the diameter of the cone bottom, the shell thickness, the perimeter length, the flask radius, the perimeter thickness, the end face thickness, and the base height, to achieve Pareto optimality of multiple target performance parameters such as sound source level, bandwidth, and resonant frequency. The MSDOA algorithm, through the synergy of global search and local exploitation, and by decomposing the target performance, avoids the problem of traditional optimization methods easily getting trapped in local optima, ensuring the balance of sound source level and bandwidth, and guaranteeing the global optimality of the design parameters.

[0059] This embodiment aims to maximize both the source level (SL) and bandwidth (BW) of the array using the MSDOA algorithm, while ensuring that the resonant frequency (Fr) is within the range of 1000–1500 Hz. The optimization objectives are the resonant frequency, the source level size SL, and the corresponding bandwidth BW. SL and BW are obtained through COMSOL finite element simulation, and cannot be directly derived from the geometry using formulas. The constraint function is the resonant frequency, which is obtained through... Constraints are imposed, among which This is the resonant frequency in this finite element simulation. is the target resonant frequency value, which is taken as 1250Hz in this optimization. tolerance is the level of tolerance for resonant frequency deviation, which is taken as 250Hz in this optimization. That is, the resonant frequency is constrained to 1000-1500Hz. season and This refers to the penalty item.

[0060] The overall algorithm process is divided into two stages: the global search stage (first 60% of iterations) and the local development stage (last 40% of iterations).

[0061] Global search phase (first 60% of iterations): This phase focuses on extensively exploring the parameter space to avoid premature convergence. Four parallel search strategies are employed, each responsible for a portion of the population's solutions, to increase diversity.

[0062] Partial development phase (last 40% of iterations): Focuses on fine-grained search in potentially high-quality regions. A decomposition mechanism transforms the multi-objective problem into a series of single-objective sub-problems.

[0063] Pareto Front Extraction: After iteration, non-dominated solutions are collected from all neighborhoods to form a Pareto optimal solution set. The solution set contains a series of optimal solutions that balance source level and bandwidth.

[0064] First, a random population is generated during initialization. Then, the geometric parameters of the conical transducer are randomly set, and an initial simulation is run to evaluate the source level and bandwidth of each solution.

[0065] During the global search phase, four strategies are used to update the transducer geometry parameters of the population. During the local development phase, neighborhood optimization is performed through weighted vector decomposition.

[0066] This invention uses a multi-strategy search and decomposition mechanism to avoid local optima and find the Pareto optimal balance point between sound source level and bandwidth.

[0067] The weighted vector decomposition of this invention allows designers to select solutions based on application requirements (e.g., military detection favors high sound source levels, while communications favor wide bandwidth), enhancing design flexibility.

[0068] The parameters output by the algorithm of this invention were verified by simulation in Example 2. The sound source level was 221.5 dB and the bandwidth was 280 Hz, with no error, ensuring the reliability of the results.

[0069] Example 5 Based on the embodiment 1, the enclosed gas inside the conical transducer unit is replaced with an enclosed liquid, namely silicone oil.

[0070] Silicone oil has a much higher specific heat capacity and thermal conductivity than air. The internal liquid can effectively conduct heat to the outer shell and then dissipate it to the surrounding water, greatly improving heat dissipation performance.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A mid-frequency, high-energy-density conical giant magnetostrictive electroacoustic transducer array structure, characterized in that, The four-way cubic base (11) is included, and the direction of the line connecting the front and rear centers of the four-way cubic base (11) is the main axis direction; the four sides of the four-way cubic base (11) are fixed with transducer units of the same structure and size, and the relative transducer units are symmetrically arranged relative to the main axis. The transducer unit includes a conical shell 1 (6) located outside the four-way cubic base (11) and a conical shell 2 (7) inserted inside the four-way cubic base (11). The outer surface of the conical shell 1 (6) forms a radiating surface. The conical shell 1 (6) and the conical shell 2 (7) are fixedly connected. A magnetic upper base (1) is installed inside the conical shell 1 (6), and a magnetic lower base (2) is installed inside the conical shell 2 (7). Two parallel supermagnetic-strictive oscillators are glued and fixed between the magnetic upper base (1) and the magnetic lower base (2). An AC excitation coil (5) is provided around the supermagnetic-strictive oscillator. The supermagnetic-strictive oscillator is formed by alternating bonding of permanent magnets (4) and supermagnetic-strictive rods (3), and both ends of the supermagnetic-strictive oscillator are permanent magnets (4). The magnetic upper base (1) and the magnetic lower base (2) apply pre-tightening pressure to both ends of the supermagnetic-strictive oscillator. The adjacent permanent magnets in the transducer are placed with their poles facing each other; in the two parallel supermagnetic-strictive oscillators, one has its N pole facing upward and the other has its S pole facing upward; the AC excitation coils (5) of the four transducer units have the same input current amplitude and phase, and are wound in the same direction; the length ratio of the permanent magnet (4) to the supermagnetic-strictive rod (3) is 0.16–0.25; the permanent magnet is made of neodymium iron boron material; the cone angle of the conical shell (6) is 100°–115°, and the resonant frequency of the transducer array is in the range of 1–2kHz; the resonant frequency of the transducer array increases with the increase of the cone angle.

2. The mid-frequency high-energy-density conical supermagnetic-strictive electroacoustic transducer array structure as described in claim 1, characterized in that, The four sides of the four-way cubic base (11) are fixed with multiple lifting rings (9), and a watertight head (10) is installed at the back of the four-way cubic base (11).

3. The mid-frequency high-energy-density conical supermagnetic-strictive electroacoustic transducer array structure as described in claim 1, characterized in that, The super magnetostrictive oscillator is composed of four super magnetostrictive rods (3) and five permanent magnets (4) arranged and glued together in an alternating manner; the length of the AC excitation coil (5) is less than the length of the super magnetostrictive oscillator.

4. The mid-frequency high-energy-density conical supermagnetic-strictive electroacoustic transducer array structure as described in claim 3, characterized in that, Both the permanent magnet (4) and the super magnetostrictive rod (3) are slit-cut on their surfaces.

5. The mid-frequency high-energy-density conical supermagnetic-strictive electroacoustic transducer array structure as described in claim 4, characterized in that, The permanent magnet is 8mm long and the magnetostrictive rod is 45mm long; the length of the AC excitation coil (5) is less than the length of one permanent magnet (4) of the magnetostrictive oscillator.

6. The mid-frequency high-energy-density conical supermagnetic-strictive electroacoustic transducer array structure as described in claim 2, characterized in that, The upper magnetic base (1) and the lower magnetic base (2) are both made of DT4C electrical pure iron material; the permanent magnet (4) and the super magnetostrictive rod (3) are bonded and fixed with adhesive, which is EPO-TEKH74 series epoxy resin adhesive; the four-way cubic base (11) is made of titanium alloy or aluminum alloy; the watertight head (10) supplies power to the AC excitation coils of the four transducer units, and the eight AC excitation coils are electrically connected in parallel.

7. The mid-frequency high-energy-density conical supermagnetic-strictive electroacoustic transducer array structure as described in claim 1, characterized in that, The four-way cubic base (11) has an installation cavity that mates with the conical shell (7); the bottom of the installation cavity is connected to the conical shell (7) via a quick-locking mechanism; the quick-locking mechanism includes a male insert ring (12) fixed to the bottom of the conical shell (7) and a female insert ring (14) fixed to the bottom of the installation cavity; the outer surface of the bottom of the male insert ring (12) has an inverted L-shaped groove (121); the inner surface of the female insert ring (14) is provided with a locking block (141) that mates with the inverted L-shaped groove (121); the male insert ring (12) is inserted into the female insert ring (14) while the locking block (141) is inserted into the inverted L-shaped groove (121); the conical shell (7) and the four-way cubic base (11) can be quickly engaged or disengaged by rotation.

8. The mid-frequency high-energy-density conical supermagnetic-strictive electroacoustic transducer array structure as described in claim 1, characterized in that, The first conical shell (6) and the second conical shell (7) of the transducer unit are respectively fixed to the upper magnetic base (1) and the lower magnetic base (2) by positioning pins; the positioning pins are made of aluminum alloy; the length of the super magnetostrictive oscillator is 0.2-0.8 mm greater than the height of the internal cavity of the transducer; A thin sheet (61) is fixed to the outer periphery of the first conical shell (6). The thin sheet (61) is fastened to the second conical shell (7) and the four-way cubic base (11) by fastening bolts (8). The fastening force of the fastening bolts (8) provides mechanical prestress for the super magnetostrictive drive module. The mechanical prestress is superimposed with the stress introduced by the working water depth to form the total prestress. Adjust the total prestress so that the super magnetostrictive rod works in the linear region of magnetostriction and is located at the point where the slope of the strain-magnetic field strength curve is the maximum. Each mounting cavity of the four-way cubic base (11) is machined with an annular sealing groove (13), and a sealing gasket is placed in the annular sealing groove. When the four-way cubic base (11) is connected to the conical shell of the four transducer units (7), the sealing gasket is compressed under the tightening force of the fastening bolts (8), so that the sealing gasket undergoes elastic deformation and fills all micro-uneven areas, thereby forming a watertight barrier at the contact interface.

9. The mid-frequency high-energy-density conical supermagnetic-strictive electroacoustic transducer array structure as described in claim 1, characterized in that, The transducer unit size does not exceed Ф390mm*300mm; the four-way cubic base size does not exceed 500mm*500mm*500mm; the medium-frequency high energy density conical super magnetostrictive electroacoustic transducer array size does not exceed 730mm*730mm*570mm; the conical shell one (6) and conical shell two (7) are made of aluminum alloy; the transducer unit's closed inner cavity is filled with air or silicone oil.

10. The mid-frequency high-energy-density conical supermagnetic-strictive electroacoustic transducer array structure according to claim 1, characterized in that: A multi-strategy decomposition optimization algorithm was used to optimize the parameters of the electroacoustic transducer array structure. The optimization objectives were the resonant frequency source level size SL and the corresponding bandwidth size BW. Both SL and BW were obtained through COMSOL finite element simulation. The constraint function was the resonant frequency, which was constrained by c=abs(f_r-target_f)-tolerance, where f_r was the resonant frequency in this finite element simulation, target_f was the target resonant frequency value (taken as 1250Hz in this optimization), and tolerance was the tolerance for resonant frequency deviation. When c>0, SL and BW were set to 0. The parameters of the electroacoustic transducer array structure include the diameter of the top of the cone, the diameter of the bottom of the cone, the width of the sheet, the thickness of the shell, the thickness of the end face, the thickness of the four sides, the length of the four sides, and the thickness of the magnetic base. The multi-strategy decomposition optimization algorithm performs a global search in the first 60% of the iterations. The global search phase includes four parallel search strategies: The first is the extended search strategy, which combines historical best solutions, population average position and random perturbation to explore a wide range of areas, aiming to quickly locate potential high-quality solution regions. The strategy expression is as follows: in, It is the historical best solution in the current population. It is the current iteration number. It is the total number of iterations. It is the average position of the current population. It is a random number in the range [0,1]. and These are the upper and lower bounds of the search space. These are adaptive parameters that decrease with increasing iteration count, designed to quickly scan the entire search space and locate potential high-quality regions. This represents the search function corresponding to the first strategy; The second approach is a stochastic search strategy based on Lévy flight. By introducing a stochastic step size that follows a Lévy distribution, it balances global exploration with local exploitation and effectively avoids getting trapped in local optima. The strategy expression is as follows: It is the Lévy flight function, which generates random step sizes that follow a Lévy distribution. It is a randomly selected individual that, through Levi's flight, effectively balances exploration and development; its large, random step size allows it to escape local optima. This represents the search function corresponding to the second strategy; The third approach is a targeted development strategy, which relies on historical best solutions and population distribution guidance to fine-tune parameters in the neighborhood of high-quality solutions in order to improve the quality of solutions. The strategy expression is as follows: in These are adaptive parameters that control the development intensity. The targeted development strategy focuses on fine-tuning parameters in high-quality areas to improve the quality of the solution. This represents the search function corresponding to the third strategy; The fourth strategy is the balanced search strategy, which enhances convergence accuracy while maintaining search diversity by adjusting the mass function and motion parameters. The strategy expression is as follows; It is a quality function used for balance search. and These are motion parameters, adjusted with the iteration parameters. and Introducing randomness and Lévy perturbation, Make fine adjustments; This represents the search function corresponding to the fourth strategy; In the last 40% of iterations of the multi-strategy decomposition optimization algorithm, a Chebyshev scalarization function is used to perform local multi-objective search optimization. The function expression is as follows: This represents a transducer design scheme; =( , ): The weight vector representing the i-th subproblem. This represents different preferences for sound source level and bandwidth, and + =1; j =1 or 2; =( , ), This indicates the optimal value for the sound source level. Indicates optimal bandwidth Values; record the level of the sound source currently found. and bandwidth The optimal value; by finding a solution that makes the source level and bandwidth With the ideal point The deviation is minimized to obtain a set of uniformly distributed Pareto optimal solutions, from which the best combination of structural parameters is selected.

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