Underwater structure function integrated design method

Abstract

The invention discloses an underwater structure function integrated design method. A designed pressure-resistant anti-impact sound insulation unit comprises a Y-like outer frame, an upper middle thick beam and a thin oblique beam. The Y-like outer frame comprises two side thick beams, two thick oblique beams and a lower middle thick beam, the two side thick beams and the two thick oblique beams are symmetrically arranged, the lower middle thick beam and the upper middle thick beam are coaxially arranged, the side thick beams and the lower middle thick beam are connected through the thick oblique beams, and the lower middle thick beam is connected with the lower panel; the upper end of the upper middle thick beam extends out of the Y-like outer frame and is connected with the upper panel, and a gap is reserved between the lower end of the upper middle thick beam and the lower middle thick beam; the two ends of the thin oblique beams are connected with the side thick beams and the upper middle thick beams respectively. Sound waves are effectively blocked or reflected through impedance mismatch between media, equipment noise transmitted to the external environment is reduced, the effective thickness # imgabs0 # and the sound insulation index STL serve as evaluation indexes, design parameters are adjusted, and the structure can have the pressure-resistant and impact-resistant performance and the excellent sound insulation performance.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater multifunctional structures, and in particular to a design method for an underwater structure with integrated pressure resistance and impact resistance functions and excellent sound insulation performance. Background Art

[0002] With the development of underwater equipment and vehicles, concealment and impact resistance have become the key to design. Equipment needs to withstand huge water pressure in the deep sea, requiring the structure to have good pressure resistance, and also needs to cope with weapon impact to ensure impact resistance. In order to reduce sonar detection, sound insulation performance is also particularly important. The sound insulation structure can reduce the transmission of noise inside the equipment to the outside, thereby reducing the probability of being detected by sonar. Therefore, the design of underwater multifunctional structures needs to consider how to isolate the mechanical noise of underwater equipment to the maximum extent while meeting the pressure resistance and impact resistance to achieve a concealed effect. Traditional sound insulation materials rely on the high rigidity of the material to increase the acoustic impedance, but in an underwater environment, the acoustic impedance of water is similar to that of common solid materials such as metals or polymers, resulting in limited underwater sound insulation effects of traditional methods.

[0003] Chinese patent CN118520526A discloses a low-frequency sound absorption and broadband impact-resistant superstructure, whose impact-resistant sound absorption unit includes two panels made of pressure-resistant composite materials, an impact-resistant lattice structure and a damping layer containing cavities, a panel is arranged at the upper and lower ends of the damping layer, and the impact-resistant lattice structure is arranged in the damping layer; the lattice structure is a simple cube of a hexahedral rod unit, including twelve rods with square cross-sections, and a rectangular frame composed of four upper and lower crossbars connects the upper and lower panels respectively. The superstructure has excellent mechanical properties, and the maximum deformation under strong impact is only 6mm; and it has good underwater sound absorption performance. Its simulation model has a sound absorption coefficient of more than 0.7 within a certain range, and the sound absorption peak value at some positions can reach more than 0.9. However, the sound absorption principle of this structural form of superstructure is to convert sound wave energy into heat energy through the viscoelasticity of rubber in the structure, thereby reducing the intensity of sound waves when propagating in water. It is mainly used for noise control of acoustic equipment and interference noise management of underwater communication equipment. Summary of the invention

[0004] The main purpose of the present invention is to provide a method for integrated design of underwater structure functions. The pressure-resistant, impact-resistant and sound-insulating structure designed by this method can effectively block or reflect sound waves in an underwater environment mainly through impedance mismatch between media, preventing them from penetrating materials or structures. It is mainly used to reduce the noise of equipment transmitted to the external environment, thereby maintaining concealment, so that the pressure-resistant, impact-resistant and sound-insulating structure has both pressure-resistant and impact-resistant performance and excellent sound insulation performance.

[0005] The technical solution adopted by the present invention is: A pressure-resistant, impact-resistant and sound-insulating structure, comprising an upper panel (10), a lower panel (20) and a plurality of pressure-resistant, impact-resistant and sound-insulating units (30) arranged in an array between the upper panel and the lower panel; the pressure-resistant, impact-resistant and sound-insulating units (30) comprising a quasi-Y-shaped outer frame (31), an upper middle thick beam (32) and a thin oblique beam (33); the quasi-Y-shaped outer frame (31) comprising two side thick beams (311) and two thick oblique beams (312) symmetrically arranged about an axis where the upper middle thick beam (32) is located, and a lower middle thick beam (311) coaxially arranged with the upper middle thick beam (32); 3), the side thick beam (311) and the lower middle thick beam (313) are connected via a thick oblique beam (312), and the lower middle thick beam (313) is connected to the lower panel (20); the upper end of the upper middle thick beam (32) extends outside the Y-shaped outer frame (31) and is connected to the upper panel (10), and a gap is left between the lower end of the upper middle thick beam (32) and the lower middle thick beam (313); the thin oblique beam (33) is symmetrically arranged about the axis of the upper middle thick beam (32), and the two ends are respectively connected to the side thick beam (311) and the upper middle thick beam (32).

[0006] In the above solution, the upper panel (10) and the lower panel (20) are made of alloy material, carbon fiber composite material or glass fiber reinforced plastic composite material; and the pressure-resistant, impact-resistant and sound-insulating unit (30) is made of rigid resin, viscoelastic resin, nylon, carbon fiber composite material or metal material.

[0007] In the above solution, two or more groups of the thin oblique beams (33) are arranged along the axis direction of the upper middle thick beam (32).

[0008] In the above solution, the pressure-resistant, impact-resistant and sound-insulating unit (30) maintains axis mirror symmetry and satisfies In order to keep the same rigidity constraints at both ends of the thin inclined beam (33), keep , the upper middle thick beam (32) and the lower middle thick beam (313) are kept of equal thickness.

[0009] The present invention also proposes a method for integrated design of underwater structure functions, comprising the following steps: S1. Determine that the underwater structure has integrated pressure-resistant, impact-resistant and sound-insulating functions, and design a pressure-resistant, impact-resistant and sound-insulating structure with the structural form as described above; S2. Determine the working conditions of the pressure-resistant, impact-resistant and sound-insulating structure, including hydrostatic pressure , shock wave pressure peak , shock wave attenuation coefficient α , incident sound pressure ; S3. Determine the parameters of the pressure-resistant, impact-resistant and sound-insulating structure, including: xThe total transverse length L in the y direction and the total longitudinal width W in the y direction; the transverse length L1 and the width W0 of the thick beam in the upper middle part; the width W1 of the thick beam at the side; the length L0 and the thickness of the thin oblique beam t , the angle between the thin inclined beam and the horizontal direction ;Thickness of upper and lower panels h p , length B, width H; number of dots of pressure-resistant, impact-resistant and sound-insulating units n ; Then the equivalent strength of the pressure-resistant, impact-resistant and sound-insulating structure is calculated through quasi-static compression test or finite element simulation and densification strain ; S4. Calculate the effective thickness of the pressure-resistant and impact-resistant sound insulation structure under the corresponding static pressure and impact conditions through theoretical formulas , the effective thickness is defined as the thickness of the pressure-resistant, impact-resistant and sound-insulating structure when the shock wave is completely dissipated; S5. Calculate the pressure-resistant and impact-resistant sound insulation structure at the corresponding incident sound pressure by combining theoretical formulas and finite element simulation. The sound insulation under STL; S6, effective thickness and sound insulation STL as evaluation indicators, adjust the design parameters of the pressure-resistant and impact-resistant sound insulation unit, including: x The total transverse length L in the y direction and the total longitudinal width W in the y direction; the transverse length L1 and the width W0 of the thick beam in the upper middle part; the width W1 of the thick beam at the side; the length L0 and the thickness of the thin oblique beam t , the angle between the thin inclined beam and the horizontal direction θ ; Calculate the effective thickness again and sound insulation STL, optimize the design of the pressure-resistant, impact-resistant and sound-insulating structure to determine the optimal design parameters of the pressure-resistant, impact-resistant and sound-insulating structure.

[0010] In the above method, in step S2, the load-displacement curve of the pressure-resistant, impact-resistant and sound-insulating structure is obtained by quasi-static compression test or finite element simulation calculation; the stress-strain curve is obtained by converting the load-displacement curve, and the stress peak value of the elastic section of the stress-strain curve is the equivalent strength ; The energy absorption efficiency-strain curve is obtained by integrating the stress-strain curve. The peak value of the energy absorption efficiency-strain curve corresponds to the densification strain. .

[0011] In the above method, in step S3, the effective thickness The calculation formula is: (11) In the formula, It is the effective thickness of the pressure-resistant, impact-resistant and sound-insulating structure. is the peak pressure of the shock wave, α is the shock wave attenuation coefficient, is the hydrostatic pressure, It is the equivalent strength of the pressure-resistant, impact-resistant and sound-insulating structure. is the densification strain, U2 is the peak value at a given pressure and the hydrostatic pressure is The compression of the pressure-resistant, impact-resistant and sound-insulating structure, is the speed of shock wave propagation in water.

[0012] In the above method, step S4 specifically includes: The incident sound pressure in the background pressure field is When , the incident sound intensity is (12) In the formula, is the incident sound intensity, p in is the incident sound pressure, is the density of the medium where the incident sound field is located, is the propagation speed of the shock wave in water, It represents the wave impedance of the medium where the incident sound field is located; Then the incident sound power is: (13) In the formula, W in is the incident sound power, I in is the incident sound intensity, It is the upper surface of the pressure-resistant, impact-resistant and sound-insulating structure. Indicates the total transverse length of the pressure-resistant, impact-resistant and sound-insulating unit. Indicates the total longitudinal width of the pressure-resistant, impact-resistant and sound-insulating unit; Similarly, the transmitted sound power is: (14) In the formula, W out is the transmitted sound power, It is the lower surface of the pressure-resistant, impact-resistant and sound-insulating structure. for The transmitted sound intensity at the surface is calculated by finite element simulation; According to the law of conservation of energy, the sound insulation STL can be calculated by the incident sound power and the transmitted sound power. The formula is: (15).

[0013] In the above method, in step S5, in order to meet the requirements of impact resistance and pressure resistance, the effective thickness L effNot less than 0.5 and not more than 2.0; in order to meet the stealth requirements, for sound waves in the low-frequency range of 20Hz to 500 Hz, the STL shall not be less than 30 dB.

[0014] In the above method, in step S5, the method for adjusting the design parameters of the pressure-resistant, impact-resistant and sound-insulating unit is: first, the mirror symmetry along the axis of the pressure-resistant, impact-resistant and sound-insulating unit is maintained, and the In order to keep the same rigidity constraints at both ends of the thin beam, keep , the upper middle thick beam and the lower middle thick beam are kept equal in thickness; select any two parameters in the structural design parameters as variables, keep other parameters as fixed values, use binary sampling to evenly divide the value ranges of these two core variables into two-dimensional intervals, ensure that each interval is selected at least once during the sampling process, and calculate the effective thickness L of the pressure-resistant, impact-resistant and sound-insulating unit eff and sound insulation STL; when the calculated result does not meet the project index requirements, continue to iteratively optimize the two core design parameters in the two-part pressure-resistant and impact-resistant sound insulation unit until the project index requirements are met.

[0015] The beneficial effects produced by the present invention are: The pressure-resistant, impact-resistant and sound-insulating structure designed by the present invention controls the length L0 and thickness L1 of the thin inclined beam of the pressure-resistant, impact-resistant and sound-insulating unit. t , the angle between the thin inclined beam and the horizontal direction θ , which can effectively control the equivalent strength and densification strain of the structure, thereby overcoming the problem of poor pressure resistance of air cavity materials in traditional structures, and making the structure meet the requirements of pressure resistance and impact resistance; at the same time, by calculating the sound insulation, the impedance difference between the structure and the medium is controlled, the impedance mismatch between the structure and the medium is achieved, and strong wave reflection and good sound insulation effect are achieved; therefore, the pressure-resistant and impact-resistant sound insulation structure designed by the present invention can effectively block underwater sound waves in the low frequency band (20Hz to 500Hz), and ensure the stability and impact resistance of the structure under high pressure environment, which is suitable for the stealth and impact resistance requirements of submarines, ships and other underwater equipment.

[0016] The underwater structure function integrated design method proposed in the present invention is based on the effective thickness The design parameters of the pressure-resistant and impact-resistant sound insulation unit are adjusted using the sound insulation value STL as the evaluation index, among which the effective thickness It can well control the pressure and impact resistance of the structure. The sound insulation value STL can control the sound insulation effect of the structure, so that the designed pressure-resistant and impact-resistant sound insulation structure has both pressure-resistant and impact-resistant performance and excellent sound insulation performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of the overall structure of the pressure-resistant, impact-resistant and sound-insulating structure designed by the present invention; Figure 2 yes Figure 1 A schematic structural diagram of a pressure-resistant, impact-resistant and sound-insulating unit of the pressure-resistant, impact-resistant and sound-insulating structure shown; Figure 3 yes Figure 1 A schematic diagram of the structure of the upper and lower panels of the pressure-resistant, impact-resistant and sound-insulating structure shown; Figure 4 It is a flow chart of the design method of the pressure-resistant, impact-resistant and sound-insulating structure of the present invention; Figure 5 It is a typical stress-strain curve of the pressure-resistant, impact-resistant and sound-insulating structure of the present invention under quasi-static compression; Figure 6 It is a typical energy absorption efficiency-strain curve of the pressure-resistant, impact-resistant and sound-insulating structure of the present invention under quasi-static compression; Figure 7 It is the unit cell form and sound insulation calculation model of the pressure-resistant and impact-resistant sound insulation structure of the present invention; Figure 8 It is the calculation result of the sound insulation value of the pressure-resistant and impact-resistant sound insulation structure of the present invention.

[0019] In the figure: 10, upper panel; 20, lower panel; 30, pressure-resistant, impact-resistant and sound-insulating unit; 31, Y-shaped outer frame; 311, thick edge beam; 312, thick oblique beam; 313, lower middle thick beam; 32, upper middle thick beam; 33, thin oblique beam. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0021] It should be noted that the illustrations provided in the embodiments of the present invention are only used to illustrate the basic concept of the present invention in a schematic manner. Therefore, the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout type may also be more complicated.

[0022] In the present invention, it is also necessary to explain that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, if the terms "first" and "second" appear, they are only used for description and distinction purposes, and cannot be understood as indicating or implying relative importance.

[0023] like Figure 1 As shown, a pressure-resistant, impact-resistant and sound-insulating structure designed by the present invention is similar to the structure of a diode, and includes an upper panel 10, a lower panel 20, and a plurality of pressure-resistant, impact-resistant and sound-insulating units 30 arranged in an array between the upper panel and the lower panel. Figure 2 As shown, the pressure-resistant, impact-resistant and sound-insulating unit 30 includes a Y-shaped outer frame 31, an upper middle thick beam 32 and a thin oblique beam 33; the Y-shaped outer frame 31 includes two side thick beams 311 and two thick oblique beams 312 symmetrically arranged about the axis of the upper middle thick beam 32, and a lower middle thick beam 313 coaxially arranged with the upper middle thick beam 32, the side thick beam 311 and the lower middle thick beam 313 are connected through the thick oblique beam 312, and the lower middle thick beam 313 is connected to the lower panel 20; the upper end of the upper middle thick beam 32 extends outside the Y-shaped outer frame 31 and is connected to the upper panel 10, and a gap is left between the lower end of the upper middle thick beam 32 and the lower middle thick beam 313; the thin oblique beam 33 is symmetrically arranged about the axis of the upper middle thick beam 32, and the two ends are respectively connected to the side thick beam 311 and the upper middle thick beam 32.

[0024] The pressure-resistant, impact-resistant and sound-insulating structure designed by the present invention is designed by controlling the length L0 and thickness L1 of the thin inclined beam 33 of the pressure-resistant, impact-resistant and sound-insulating unit. t , the angle between the thin inclined beam 33 and the horizontal direction θ , which can effectively control the equivalent strength and densification strain of the structure, so that the structure meets the requirements of pressure resistance and impact resistance; at the same time, by calculating the sound insulation, the impedance difference between the structure and the medium is controlled, the impedance mismatch between the structure and the medium is achieved, and strong wave reflection and good sound insulation effect are achieved; in this way, the structure has both pressure resistance and excellent sound insulation performance. For the parameters of pressure resistance and impact resistance sound insulation structure, see Figure 2 , pressure-resistant and impact-resistant sound insulation unit 30 along x The total transverse length along the y direction is L, and the total longitudinal width along the y direction is W; the transverse length of the upper middle thick beam 32 is L1, and the width is W0; the width of the side thick beam 311 is W1; the main bearing deformation is the middle thin inclined beam 33, whose length is L0 and its thickness is t , the angle between the thin inclined beam 33 and the horizontal direction is See also Figure 3 , the upper and lower panels are along x The total transverse length in the y direction is B, the total longitudinal width in the y direction is H, and the thickness is h p The number of dots in the pressure-resistant and impact-resistant sound insulation unit 30 is n .

[0025] Further optimization, the pressure-resistant and impact-resistant sound insulation unit 30 maintains axis mirror symmetry and meets In order to keep the same rigidity constraint at both ends of the thin diagonal beam 33, keep , the upper middle thick beam 32 and the lower middle thick beam 313 maintain the same thickness.

[0026] Further optimization, the upper panel 10 and the lower panel 20 are made of alloy materials (such as aluminum alloy, titanium alloy, etc.), carbon fiber composite materials or glass fiber reinforced plastic composite materials, etc., which usually have extremely high strength and fatigue resistance and can withstand large mechanical stress and impact. The pressure-resistant and impact-resistant sound insulation unit (30) is made of rigid resin, viscoelastic resin, nylon, carbon fiber composite materials or metal materials, etc., which have good mechanical properties and dimensional stability and can provide good support and structural strength.

[0027] For further optimization, two or more groups of thin oblique beams 33 are arranged along the axis where the upper middle thick beam 32 is located.

[0028] The present invention also proposes a method for integrating underwater structural functions. Figure 4 , including the following steps: S1. Determine that the underwater structure is integrated with pressure resistance, impact resistance and sound insulation functions, and design it as follows: Figure 1 The pressure-resistant, impact-resistant and sound-insulating structure of the structural form shown; S2. Determine the working conditions of the pressure-resistant, impact-resistant and sound-insulating structure, including hydrostatic pressure , shock wave pressure peak , shock wave attenuation coefficient α , incident sound pressure .

[0029] Hydrostatic Pressure By corresponding water depth The calculation can be obtained: (1) In the formula, is the hydrostatic pressure, is the density of water, is the acceleration due to gravity, h For water depth.

[0030] Peak shock wave pressure , shock wave attenuation coefficientα It can be obtained by calculating the corresponding amount of explosives and explosion distance under the working condition. The shock wave generated by the underwater explosion is the type of shock wave that the pressure-resistant, impact-resistant and sound-insulating structure faces. The peak pressure of the shock wave The calculation formula is: (2) In the formula, is the peak pressure of the shock wave, W Indicates the dosage, R Indicates the distance from the center of the explosion. R 0 means the dose radius.

[0031] Shock wave attenuation coefficient α The calculation formula is: (3) In the formula, c is the shock wave velocity; is the normalization coefficient of the dose radius, and: (4) S3. Determine the design parameters of the pressure-resistant, impact-resistant and sound-insulating structure, including: x The total transverse length L in the y direction and the total longitudinal width W in the y direction; the transverse length L1 and the width W0 of the thick beam in the upper middle part; the width W1 of the thick beam at the side; the length L0 and the thickness of the thin oblique beam t , the angle between the thin inclined beam and the horizontal direction ;Thickness of upper and lower panels h p , length B, width H; number of dots of pressure-resistant, impact-resistant and sound-insulating units n .

[0032] Then the equivalent strength of the pressure-resistant, impact-resistant and sound-insulating structure is calculated through quasi-static compression test or finite element simulation and densification strain .

[0033] In this embodiment, the specific dimensions of a set of pressure-resistant, impact-resistant and sound-insulating structures designed are: L =23mm, W =10mm, t =0.8mm, W 1= W 0=2mm, n =10, =35°, B=230mm, H =100mm, L 1=15mm, h p=0.5mm. Finite element calculation was performed using ABAQUS, with a mesh size of 0.1mm, a loading speed of 2mm / min, and a dynamic analysis step. General contact was set in the calculation, and penalty constraints with hard contact and a friction coefficient of 0.2 were used. In addition, the upper panel was set as a rigid panel, and the load-displacement curve of the pressure-resistant, impact-resistant and sound-insulating structure was extracted.

[0034] The load-displacement curve is converted into Figure 5 The stress-strain curve of the pressure-resistant, impact-resistant and sound-insulating structure shown in the figure is converted into the following formula: (5) In the formula, is the structural stress, is the structural strain, is the axial load, is the initial cross-sectional area of ​​the structure, is the compression displacement, is the initial height.

[0035] like Figure 5 As shown in the mark, the stress peak value in the elastic section of the stress-strain curve is the equivalent strength .

[0036] Determining the densification strain It is necessary to draw the energy absorption efficiency-strain curve and integrate the stress-strain curve to obtain Figure 6 The energy absorption efficiency-strain curve is shown, and the energy absorption efficiency calculation formula is: (6) In the formula, is the energy absorption efficiency of the structure, Expressed as stress as strain The function of The strain ranges from 0 to The maximum stress value of the interval, is the maximum strain of the structure under compression.

[0037] like Figure 6 As shown in the mark, the strain corresponding to the peak of the energy absorption efficiency-strain curve is the densification strain .

[0038] S4. Calculate the effective thickness of the pressure-resistant and impact-resistant sound insulation structure under the corresponding static pressure and impact conditions through theoretical formulas , the effective thickness is defined as the thickness of the pressure-resistant, impact-resistant and sound-insulating structure when the shock wave is completely dissipated.

[0039] The normalized numerical fitting result of the compression of the pressure-resistant, impact-resistant and sound-insulating structure is: (7) In the formula, U is the compression amount of the pressure-resistant, impact-resistant and sound-insulating structure. is the propagation speed of shock waves in water, generally 1500m / s, α is the shock wave attenuation coefficient, It is the equivalent strength of the pressure-resistant, impact-resistant and sound-insulating structure. is the peak value of shock wave pressure.

[0040] According to formula (7), the equivalent strength is A given pressure-resistant, impact-resistant and sound-insulating structure at a given pressure peak and hydrostatic pressure The compression amount when it is 0 is: (8) In the formula, U 1 is when The compression of the pressure-resistant, impact-resistant and sound-insulating structure. is the hydrostatic pressure.

[0041] The fitting function of the compression increase rate of the known pressure-resistant, impact-resistant and sound-insulating structure is: (9) In the formula, It is the compression increase rate of the pressure-resistant, impact-resistant and sound-insulating structure.

[0042] Combining the above formula, the equivalent strength is solved as follows: A given pressure-resistant, impact-resistant and sound-insulating structure at a given pressure peak and the hydrostatic pressure is Compression amount at : (10) In the formula, U2 is and The compression amount of the pressure-resistant, impact-resistant and sound-insulating structure under given conditions.

[0043] Calculate the effective thickness of the pressure-resistant, impact-resistant and sound-insulating structure: (11) In the formula, It is the effective thickness of the pressure-resistant, impact-resistant and sound-insulating structure. is the peak pressure of the shock wave, α is the shock wave attenuation coefficient, is the hydrostatic pressure, It is the equivalent strength of the pressure-resistant, impact-resistant and sound-insulating structure. Densification strain.

[0044] In this embodiment, the effective thickness calculated according to formula (11) is =1.2765.

[0045] S5. Calculate the pressure-resistant and impact-resistant sound insulation structure at the corresponding incident sound pressure by combining theoretical formulas and finite element simulation. The sound insulation STL below.

[0046] The incident sound pressure in the background pressure field is When , the incident sound intensity is (12) In the formula, is the incident sound intensity, p in is the incident sound pressure, is the density of the medium where the incident sound field is located, is the propagation speed of the shock wave in water, It represents the wave impedance of the medium where the incident sound field is located.

[0047] Then the incident sound power is: (13) In the formula, W in is the incident sound power, I in is the incident sound intensity, It is the upper surface of the pressure-resistant, impact-resistant and sound-insulating structure. Indicates the total transverse length of the pressure-resistant, impact-resistant and sound-insulating unit. Indicates the total longitudinal width of the pressure-resistant, impact-resistant and sound-insulating unit.

[0048] Similarly, the transmitted sound power is: (14) In the formula, W out is the transmitted sound power, It is the lower surface of the pressure-resistant, impact-resistant and sound-insulating structure. for The transmitted sound intensity at the surface.

[0049] Specifically, The calculation model of the unit cell is obtained through finite element simulation as shown in the attached figure. Figure 7 As shown in the figure, the model is composed of a water area perfect matching layer, a water area, a pressure-resistant, impact-resistant and sound-insulating structure unit cell, an air domain, and an air domain perfect matching layer from bottom to top. The water area perfect matching layer simulates the infinite water area on the outside, and the air domain perfect matching layer simulates the infinite air area on the inside. The plane sound waves generated by the equipment are incident vertically from the air domain to the pressure-resistant, impact-resistant and sound-insulating structure unit cell. The Floquet boundary conditions are set around the model. The pressure of the plane wave is 1MPa, the mesh uses quadratic tetrahedron units, the mesh size is 0.5mm, and the scanning frequency range is 10Hz to 1000Hz.

[0050] According to the law of conservation of energy, the sound insulation STL can be calculated by the incident sound power and the transmitted sound power. The formula is: (15) Specifically, in this embodiment, the sound insulation STL and frequency results of the pressure-resistant and impact-resistant sound insulation structure are shown in the attached figure. Figure 8 As shown in the figure, it can be seen that the sound insulation gradually decreases in the low frequency band (10 Hz to 100 Hz), especially when it is close to 100 Hz, a significant valley appears, and the sound insulation effect is significantly worse. Then in the frequency band of 100 Hz to 1000 Hz, the sound insulation shows a fluctuating trend, and multiple frequency bands reach higher sound insulation values, with the highest value close to 80 dB, showing good sound insulation performance at higher frequencies. This shows that the structure has a significant sound insulation effect in the high frequency band, but the sound insulation performance is poor in the low frequency band and at the resonant frequency close to 100 Hz, which requires further calculation and optimization to obtain better sound insulation performance.

[0051] S6, effective thickness and sound insulation STL as evaluation indicators, adjust the design parameters of the pressure-resistant and impact-resistant sound insulation unit, including: x The total transverse length L in the y direction and the total longitudinal width W in the y direction; the transverse length L1 and the width W0 of the thick beam in the upper middle part; the width W1 of the thick beam at the side; the length L0 and the thickness of the thin oblique beam t , the angle between the thin inclined beam and the horizontal direction θ The effective thickness is calculated by the theoretical formula (11): The sound insulation STL is calculated by repeatedly iterating formula (15) using the finite element method to optimize the design of the pressure-resistant and impact-resistant sound insulation structure to determine the optimal design parameters of the pressure-resistant and impact-resistant sound insulation structure.

[0052] In order to meet the requirements of impact resistance and pressure resistance, the effective thickness L eff Not less than 0.5, but too high L eff This would result in a heavy structure and high manufacturing costs, so L eff Not higher than 2.0. In order to meet the stealth requirements of underwater structures, STL usually needs to reach 30 dB in the low frequency range (20Hz to 500 Hz). For high-precision underwater acoustic systems, STL is required to exceed 60 dB. The method for adjusting the design parameters of the pressure-resistant and impact-resistant sound insulation unit is as follows: Specifically, in this embodiment, the binary sampling optimization structure design is adopted to select and optimize the thickness of the thin inclined beam in the pressure-resistant, impact-resistant and sound-insulating structure. t and the angle between the thin inclined beam and the horizontal direction , the thickness of the thin diagonal beam t The value range is 0.1mm to 1mm, and the angle The value range is , respectively, to compare the thickness of the thin inclined beam t The effective thickness at both ends is 0.1-0.5mm The effective thickness at the two endpoints is 0.5mm-1mm , to determine whether it meets the above requirements for impact resistance and pressure resistance. On the basis of meeting the above requirements, if the effective thickness of the former If it is smaller than the latter, then choose to continue the binary division within the difference between the endpoints of the former. At this time, the binary division interval is 0.1-0.25mm and 0.25mm-0.5mm to continue to determine the effective thickness L eff Whether the conditions are met, so as to determine the thickness of the thin inclined beam in the pressure-resistant and impact-resistant sound insulation structure on the basis of ensuring the maximum bearing capacity of the pressure-resistant and impact-resistant structure t And calculate its sound insulation STL through finite element. In addition, it is necessary to mix the angle of the thinner inclined beam exist and Effective thickness in two intervals The comparison method is the same as the thickness method of the thin inclined beam mentioned above, and the comparison is repeated iteratively until the effective thickness of the two intervals is The sound insulation STL meets the above-mentioned pressure-resistant, impact-resistant and sound insulation evaluation indicators at the same time, and the difference in structural parameters at the two endpoints is less than 1%. At this time, the pressure-resistant, impact-resistant and sound insulation structural design parameters are the optimal parameters.

[0053] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0054] The order of execution of each step in the above embodiment does not mean the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

[0055] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A pressure-resistant, impact-resistant and sound-insulating structure, comprising an upper panel (10), a lower panel (20) and a plurality of pressure-resistant, impact-resistant and sound-insulating units (30) arranged in an array between the upper panel and the lower panel; characterized in that: The pressure-resistant, impact-resistant and sound-insulating unit (30) comprises a quasi-Y-shaped outer frame (31), an upper middle thick beam (32) and a thin oblique beam (33); the quasi-Y-shaped outer frame (31) comprises two side thick beams (311) and two thick oblique beams (312) symmetrically arranged about the axis of the upper middle thick beam (32), and a lower middle thick beam (313) coaxially arranged with the upper middle thick beam (32); the side thick beam (311) and the lower middle thick beam (313) are connected by a thick oblique beam ( The upper middle thick beam (313) is connected to the lower panel (20); the upper end of the upper middle thick beam (32) extends outside the Y-shaped outer frame (31) and is connected to the upper panel (10); a gap is left between the lower end of the upper middle thick beam (32) and the lower middle thick beam (313); the thin oblique beam (33) is symmetrically arranged about the axis of the upper middle thick beam (32), and the two ends are respectively connected to the side thick beam (311) and the upper middle thick beam (32).

2. The pressure-resistant, impact-resistant and sound-insulating structure according to claim 1, characterized in that: The upper panel (10) and the lower panel (20) are made of alloy material, carbon fiber composite material or glass fiber reinforced plastic composite material; the pressure-resistant, impact-resistant and sound-insulating unit (30) is made of rigid resin, viscoelastic resin, nylon, carbon fiber composite material or metal material.

3. The pressure-resistant, impact-resistant and sound-insulating structure according to claim 1, characterized in that: The thin oblique beams (33) are arranged in two or more groups along the axis direction of the upper middle thick beam (32).

4. The pressure-resistant, impact-resistant and sound-insulating structure according to claim 1, characterized in that: The pressure-resistant, impact-resistant and sound-insulating unit (30) maintains mirror symmetry along its axis and satisfies In order to keep the same rigidity constraints at both ends of the thin inclined beam (33), keep , the upper middle thick beam (32) and the lower middle thick beam (313) are kept of equal thickness.

5. A method for integrated design of underwater structure functions, characterized in that: The following steps are involved: S1. Determine that the underwater structure has integrated pressure-resistant, impact-resistant and sound-insulating functions, and design a pressure-resistant, impact-resistant and sound-insulating structure in the form of any one of claims 1 to 4; S2. Determine the working conditions of the pressure-resistant, impact-resistant and sound-insulating structure, including hydrostatic pressure , shock wave pressure peak , shock wave attenuation coefficient α , incident sound pressure ; S3. Determine the parameters of the pressure-resistant, impact-resistant and sound-insulating structure, including: x The total transverse length L in the y direction and the total longitudinal width W in the y direction; the transverse length L1 and the width W0 of the thick beam in the upper middle part; the width W1 of the thick beam at the side; the length L0 and the thickness of the thin oblique beam t , the angle between the thin inclined beam and the horizontal direction ;Thickness of upper and lower panels h p , length B, width H; number of dots of pressure-resistant, impact-resistant and sound-insulating units n ; Then the equivalent strength of the pressure-resistant, impact-resistant and sound-insulating structure is calculated through quasi-static compression test or finite element simulation and densification strain ; S4. Calculate the effective thickness of the pressure-resistant and impact-resistant sound insulation structure under the corresponding static pressure and impact conditions through theoretical formulas , the effective thickness is defined as the thickness of the pressure-resistant, impact-resistant and sound-insulating structure when the shock wave is completely dissipated; S5. Calculate the pressure-resistant and impact-resistant sound insulation structure at the corresponding incident sound pressure by combining theoretical formulas and finite element simulation. The sound insulation STL under S6, effective thickness and sound insulation STL as evaluation indicators, adjust the design parameters of the pressure-resistant and impact-resistant sound insulation unit, including: x The total transverse length L in the y direction and the total longitudinal width W in the y direction; the transverse length L1 and the width W0 of the thick beam in the upper middle part; the width W1 of the thick beam at the side; the length L0 and the thickness of the thin oblique beam t , the angle between the thin inclined beam and the horizontal direction θ ; Calculate the effective thickness again and sound insulation STL, optimize the design of the pressure-resistant, impact-resistant and sound-insulating structure to determine the optimal design parameters of the pressure-resistant, impact-resistant and sound-insulating structure.

6. The underwater structure function integrated design method according to claim 5, characterized in that: In step S2, a load-displacement curve of the pressure-resistant, impact-resistant and sound-insulating structure is obtained by quasi-static compression test or finite element simulation calculation; The stress-strain curve is obtained by converting the load-displacement curve. The stress peak value in the elastic section of the stress-strain curve is the equivalent strength. ; The energy absorption efficiency-strain curve is obtained by integrating the stress-strain curve. The peak value of the energy absorption efficiency-strain curve corresponds to the densification strain. .

7. The underwater structure function integrated design method according to claim 5, characterized in that: In step S3, the effective thickness The calculation formula is: （11） In the formula, It is the effective thickness of the pressure-resistant, impact-resistant and sound-insulating structure. is the peak pressure of the shock wave, α is the shock wave attenuation coefficient, is the hydrostatic pressure, It is the equivalent strength of the pressure-resistant, impact-resistant and sound-insulating structure. is the densification strain, U2 is the peak value at a given pressure and the hydrostatic pressure is The compression of the pressure-resistant, impact-resistant and sound-insulating structure, is the speed of shock wave propagation in water.

8. The underwater structure function integrated design method according to claim 5, characterized in that: Step S4 specifically includes: The incident sound pressure in the background pressure field is When , the incident sound intensity is （12） In the formula, is the incident sound intensity, p in is the incident sound pressure, is the density of the medium where the incident sound field is located, is the propagation speed of the shock wave in water, It represents the wave impedance of the medium where the incident sound field is located; Then the incident sound power is: （13） In the formula, W in is the incident sound power, I in is the incident sound intensity, It is the upper surface of the pressure-resistant, impact-resistant and sound-insulating structure. Indicates the total transverse length of the pressure-resistant, impact-resistant and sound-insulating unit. Indicates the total longitudinal width of the pressure-resistant, impact-resistant and sound-insulating unit; Similarly, the transmitted sound power is: （14） In the formula, W out is the transmitted sound power, It is the lower surface of the pressure-resistant, impact-resistant and sound-insulating structure. for The transmitted sound intensity at the surface is calculated by finite element simulation; According to the law of conservation of energy, the sound insulation STL can be calculated by the incident sound power and the transmitted sound power. The formula is: （15）。 9. The underwater structure function integrated design method according to claim 5, characterized in that: In step S5, in order to meet the requirements of impact resistance and pressure resistance, the effective thickness L eff Not less than 0.5 and not more than 2.0; in order to meet the stealth requirements, for sound waves in the low-frequency range of 20Hz to 500 Hz, the STL shall not be less than 30 dB.

10. The underwater structure function integrated design method according to claim 5, characterized in that: In step S5, the method for adjusting the design parameters of the pressure-resistant, impact-resistant and sound-insulating unit is as follows: first, the mirror symmetry along the axis of the pressure-resistant, impact-resistant and sound-insulating unit is maintained, and In order to keep the same rigidity constraints at both ends of the thin beam, keep , the upper middle thick beam and the lower middle thick beam are kept equal in thickness; select any two parameters in the structural design parameters as variables, keep other parameters as fixed values, use binary sampling to evenly divide the value ranges of these two core variables into two-dimensional intervals, ensure that each interval is selected at least once during the sampling process, and calculate the effective thickness L of the pressure-resistant, impact-resistant and sound-insulating unit eff and sound insulation STL; when the calculated result does not meet the project index requirements, continue to iteratively optimize the two core design parameters in the two-part pressure-resistant and impact-resistant sound insulation unit until the project index requirements are met.

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