Modeling and frequency response calculation method based on acoustic impedance characteristics of submarine sediments

Abstract

The invention particularly relates to a modeling and frequency response calculation method based on acoustic impedance characteristics of submarine sediments. The method comprises the following steps: firstly, acquiring basic physical parameters such as mineral composition, porosity, solid particle volume modulus, pore fluid volume modulus and density of the sediments; then carrying out weighted average on the multi-mineral components, and calculating to obtain an equivalent bulk modulus of the solid skeleton; further determining a low-frequency limit volume modulus and a high-frequency limit volume modulus by combining a Biot theory and a fluid-solid coupling acoustic model; on the basis, a frequency-dependent effective volume modulus expression is constructed, and the equivalent acoustic impedance under different frequencies is calculated according to the frequency-dependent effective volume modulus expression. According to the method, the influence of the multi-mineral composition of the sediment and the property of the pore fluid can be considered at the same time, and the frequency dependence characteristic is introduced, so that accurate modeling of the equivalent acoustic impedance of the seabed sediment is realized, and the method has the advantages of high theoretical accuracy, wide application range and high engineering realizability.

Description

Technical Field

[0001] This invention relates to the field of underwater acoustic signal propagation modeling and characteristic analysis technology, specifically to a method for modeling and calculating the acoustic impedance characteristics and frequency response of seabed sediments, a storage medium, and a computer program product. Background Technology

[0002] In the field of underwater acoustic engineering, seabed sediments serve as an important medium for underwater sound wave propagation, and their physical properties directly affect the sound field distribution, signal propagation path, and target response characteristics. In particular, when sound waves are incident on the water-sediment interface, the equivalent acoustic impedance is a key parameter that determines the reflection coefficient and transmission coefficient, and it is widely used in scenarios such as sound propagation modeling, interface energy transfer analysis, acoustic fuze excitation evaluation, and target echo characteristic prediction.

[0003] Existing methods for calculating acoustic impedance are mostly based on low-frequency approximations or empirical numerical processing, failing to fully consider the porous medium characteristics, frequency response behavior, and skeleton-fluid coupling effect of sediments. This makes it difficult to accurately characterize the dynamic changes in equivalent acoustic impedance over a wide frequency range (e.g., 20 Hz to 10 kHz). Although Biot theory provides a theoretical basis for wave propagation mechanisms in porous media, its impedance calculation process is complex and highly dependent on parameters, hindering engineering applications. Furthermore, it lacks parameter integration and simplified modeling methods for sediments with multiple mineral components.

[0004] Therefore, there is an urgent need for a method for modeling the equivalent acoustic impedance of seabed sediments and calculating the frequency response that balances theoretical accuracy and engineering feasibility, so as to better support application needs such as underwater acoustic propagation simulation, interface energy transfer analysis and related underwater acoustic system performance evaluation.

[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] This invention provides a method for modeling acoustic impedance characteristics and calculating frequency response based on seabed sediments, a storage medium, and a computer program product, which can effectively overcome the defects existing in the prior art.

[0007] Other features and advantages of the invention will become apparent from the following detailed description, or may be learned in part by practice of the invention.

[0008] According to a first aspect of the present invention, a method for modeling acoustic impedance characteristics and calculating frequency response based on seabed sediments is provided, the method comprising: The total volume and solid particle volume of the first seabed sediment sample are obtained, and the porosity of the first seabed sediment sample is obtained based on the total volume and solid particle volume of the first seabed sediment sample. The porosity of the first seabed sediment sample is then configured as the porosity of the current seabed sediment. X-ray diffraction analysis was performed on the second seabed sediment sample to obtain its mineral composition and mass fraction, and the mineral composition and mass fraction of the second seabed sediment sample were configured as the mineral composition and mass fraction of the current seabed sediment; wherein, the first seabed sediment sample and the second seabed sediment sample came from the same area; The equivalent density of the current seabed sediments was determined by combining porosity, mineral density and mass fraction of each mineral component, and Biot-Stoll dynamic density formula. By combining the mass fraction and the bulk modulus of the single mineral framework corresponding to each mineral component, the equivalent bulk modulus of the current seabed sediment is obtained; The equivalent acoustic impedance of the current seabed sediment is determined by multiplying the real part of the equivalent bulk modulus with the equivalent density.

[0009] In some exemplary embodiments, the equivalent density of the current seabed sediment is determined by combining porosity, the mineral density and mass fraction corresponding to each mineral component, and the Biot-Stoll dynamic density formula, including: Based on the mass fraction and the mineral density corresponding to each mineral component, the volume fraction is determined, including:

[0010] in, For the first Mass fraction of the minerals For the first The mineral density of a type of mineral, This represents the total number of mineral composition types. The mineral framework density is obtained by linearly weighting the mineral densities corresponding to each mineral component according to its volume fraction, including:

[0011] The equivalent density is determined by combining porosity, mineral framework density, and the Biot-Stoll dynamic density formula, including:

[0012] in, Porosity The density of the sediment skeleton. For pore fluid density, It is the inertia enhancement factor exhibited by a fluid when it is "dragged" by a solid at high frequencies.

[0013] In some exemplary embodiments, the equivalent bulk modulus of the current seabed sediment is obtained by combining the mass fraction and the bulk modulus of the single mineral framework corresponding to each mineral component, including: The Voigt average bulk modulus and the Reuss average bulk modulus were determined based on the volume fraction and the bulk modulus of the single mineral skeleton. The Hill average bulk modulus was determined based on the Voigt average bulk modulus and the Reuss average bulk modulus. The equivalent bulk modulus is determined by combining Hill's average bulk modulus, porosity, and pore fluid bulk modulus.

[0014] In some exemplary embodiments, the equivalent bulk modulus is determined by combining the Hill average bulk modulus, porosity, and pore fluid bulk modulus, including: The average bulk modulus of Hill was determined as the bulk modulus of the mineral framework. Based on porosity, mineral framework bulk modulus, and Hertz-Mindlin contact theory, the bulk modulus of the dry framework is determined, including:

[0015] in, It is a proportionality constant, with a range of values. It is closely related to the contact force and arrangement of particles; Range of values ; Bulk modulus of the mineral framework; The high-frequency limiting effective bulk modulus is determined based on porosity, pore fluid bulk modulus, mineral framework bulk modulus, and dry framework bulk modulus. Based on porosity, pore fluid bulk modulus, mineral skeleton bulk modulus, dry skeleton bulk modulus, and the Gassmann equation, the low-frequency limiting effective bulk modulus is determined. The equivalent bulk modulus is determined based on the high-frequency limit effective bulk modulus and the low-frequency limit effective bulk modulus.

[0016] In some exemplary embodiments, the high-frequency limiting effective bulk modulus is determined based on porosity, pore fluid bulk modulus, mineral framework bulk modulus, and dry framework bulk modulus, including: Determine the volumetric compliance response of a solid mineral framework based on porosity and mineral framework bulk modulus; The ratio of the dry skeleton bulk modulus to the mineral skeleton bulk modulus is determined as the dry skeleton correction term; The high-frequency limiting effective bulk modulus is determined based on the volumetric compliance response, the skeleton correction term, and the pore fluid bulk modulus, including:

[0017] in, For volumetric compliance response, Porosity Bulk modulus of the mineral framework; For skeleton correction items, The bulk modulus of the dried skeleton; This represents the bulk modulus of the pore fluid.

[0018] In some exemplary embodiments, the equivalent bulk modulus is specifically:

[0019] in, This is the low-frequency limiting effective bulk modulus. This is the high-frequency limiting effective bulk modulus. For the frequency of the sound signal, The relaxation frequency; Among them, relaxation frequency The calculation formula is:

[0020] For pore fluid dynamic viscosity, For pore fluid density, The pore size is the pore size.

[0021] In some exemplary embodiments, the equivalent acoustic impedance of the current seabed sediment is determined based on the product of the real part of the equivalent bulk modulus and the equivalent density, including: The expression for equivalent acoustic impedance is:

[0022] in, To obtain the real part, Equivalent bulk modulus This is the equivalent density.

[0023] In some exemplary embodiments, the method for modeling and calculating the frequency response based on the acoustic impedance characteristics of seabed sediments is applied to underwater acoustic signals in the 20Hz to 10kHz frequency band.

[0024] According to a second aspect of the present invention, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the above-described method for modeling and calculating the acoustic impedance characteristics of seabed sediments.

[0025] According to a third aspect of the present invention, a computer program product is provided, on which a computer program is stored, and when the computer program is executed by a processor, it implements the above-described method for modeling and calculating the acoustic impedance characteristics of seabed sediments.

[0026] According to a fourth aspect of the present invention, an electronic device is provided, comprising: Processor; and Memory for storing the executable instructions of the processor; The processor is configured to implement the above-described method for modeling and calculating the acoustic impedance characteristics of seabed sediments and frequency response by executing the executable instructions.

[0027] The embodiments of this invention provide a method for modeling and calculating the acoustic impedance characteristics of seabed sediments, which can simultaneously consider the influence of the multi-mineral composition and pore fluid properties of sediments, and introduce frequency-dependent characteristics, thereby achieving accurate modeling of the equivalent acoustic impedance of seabed sediments. This method is applicable to engineering and scientific research fields such as acoustic propagation simulation, interface transmission loss calculation, underwater target detection performance evaluation, and sediment parameter inversion, and has the advantages of high theoretical accuracy, wide applicability, and strong engineering feasibility.

[0028] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0029] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0030] Figure 1 This schematically illustrates a flowchart of an exemplary embodiment of the present invention, which describes a method for modeling and calculating the acoustic impedance characteristics of seabed sediments and its frequency response. Figure 2 The diagram illustrates an exemplary embodiment of the present invention: a method for modeling and calculating the acoustic impedance characteristics of seabed sediments and its frequency response. Figure 3 This schematic diagram illustrates an exemplary embodiment of the present invention of using acoustic signals to model seabed sediments. Figure 4 This schematic diagram illustrates the equivalent acoustic impedance frequency response of a seabed sediment according to an exemplary embodiment of the present invention. Figure 5The diagram illustrates the composition of an electronic device according to an exemplary embodiment of the present invention. Detailed Implementation

[0031] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the invention will be more comprehensive and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0032] Furthermore, the accompanying drawings are merely illustrative of the invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0033] To address the shortcomings and deficiencies of existing technologies, this example embodiment provides a method for modeling and calculating the frequency response based on the acoustic impedance characteristics of seabed sediments. (Reference) Figure 1 As shown, it can specifically include: Step S11: Obtain the total volume and solid particle volume of the first seabed sediment sample, and obtain the porosity of the first seabed sediment sample based on the total volume and solid particle volume of the first seabed sediment sample, and configure the porosity of the first seabed sediment sample as the porosity of the current seabed sediment. Specifically, the first seabed sediment sample was taken. First, the sample was wrapped with an impermeable membrane, and the total volume was measured using the underwater displacement method. The sample was then placed in an oven (105°C) and dried for at least 24 hours to obtain the corresponding dry sediment. The volume of solid particles in the dry sediment was determined using the helium method. The porosity of seabed sediment samples can then be calculated. As shown in the following formula:

[0034] in, This represents the total volume of the first seabed sediment sample. This represents the volume of solid particles in the corresponding dry sediment.

[0035] Step S12: Perform X-ray diffraction analysis on the second seabed sediment sample to obtain the mineral composition and mass fraction of the second seabed sediment sample, and configure the mineral composition and mass fraction of the second seabed sediment sample as the mineral composition and mass fraction of the current seabed sediment; wherein, the first seabed sediment sample and the second seabed sediment sample come from the same area; Specifically, a second seabed sediment sample from the same area as the first seabed sediment sample is obtained. This second seabed sediment sample is air-dried to prevent the decomposition of organic matter and ground to a finer particle size of 200 mesh or less. X-ray diffraction analysis of the particles then reveals the total organic matter content in the second seabed sediment sample. Mineral composition and its mass fraction .

[0036] Furthermore, consulting mineral handbooks can yield common mineral compositions and their individual mineral framework bulk moduli. and single mineral density They are respectively: (1) Quartz, mineral framework bulk modulus ,density ; (2) Illite, mineral framework bulk modulus ,density ; (3) Kaolinite, mineral framework bulk modulus ,density ; (4) Montmorillonite, mineral framework bulk modulus ,density ; (5) Calcite, mineral framework bulk modulus ,density ; (6) Feldspar, mineral framework bulk modulus ,density .

[0037] Specifically, after performing X-ray diffraction analysis on the air-dried second seabed sediment samples, the diffraction peak intensities of each mineral component were obtained. And then through the reference strength ratio The quality score is obtained as follows:

[0038] in, For the first Mass fraction of mineral components; For the first The intensity of the diffraction peaks of the mineral components; For the first The reference intensity ratios of the mineral components were calculated from the crystal structure factor using the Rietveld full-spectrum fitting method.

[0039] Step S13: Combine porosity, mineral density and mass fraction of each mineral component, and Biot-Stoll dynamic density formula to determine the equivalent density of the current seabed sediment; Step S14: Combine the mass fraction and the bulk modulus of the single mineral framework corresponding to each mineral component to obtain the equivalent bulk modulus of the current seabed sediment. Step S15: Determine the equivalent acoustic impedance of the current seabed sediment based on the product of the real part of the equivalent bulk modulus and the equivalent density.

[0040] Based on steps S11 to S15 above, the influence of the multi-mineral composition and pore fluid properties of sediments can be considered simultaneously, and frequency-dependent characteristics can be introduced, thereby achieving accurate modeling of the equivalent acoustic impedance of seabed sediments. This method is applicable to engineering and scientific research fields such as acoustic propagation simulation, interface transmission loss calculation, underwater target detection performance evaluation, and sediment parameter inversion, and has the advantages of high theoretical accuracy, wide applicability, and strong engineering feasibility.

[0041] For example, step S13 above, combining porosity, the mineral density and mass fraction corresponding to each mineral component, and the Biot-Stoll dynamic density formula, determines the equivalent density of the current seabed sediment, including: Step S131, based on the mass fraction and the mineral density corresponding to each mineral component, determine the volume fraction, including:

[0042] in, For the first Mass fraction of the minerals For the first The mineral density of a type of mineral, This represents the total number of mineral composition types. Step S132: Linearly weight the mineral densities corresponding to each mineral component according to their volume fraction to obtain the mineral framework density, including:

[0043] Step S133, combining porosity, mineral framework density, and the Biot-Stoll dynamic density formula, determines the equivalent density, including:

[0044] in, Porosity The density of the sediment skeleton. For pore fluid density, It is the inertia enhancement factor exhibited by a fluid when it is "dragged" by a solid at high frequencies.

[0045] For example, in step S14, the equivalent bulk modulus of the current seabed sediment is obtained by combining the mass fraction and the single-mineral framework bulk modulus corresponding to each mineral component, including: Step S141: Determine the Voigt average bulk modulus and the Reuss average bulk modulus based on the volume fraction and the bulk modulus of the single mineral skeleton. Specifically, Voigt's average bulk modulus The calculation formula is:

[0046] in, For the first Volume fraction of the mineral components, For the first Bulk modulus of a single mineral skeleton.

[0047] Specifically, Reuss's average bulk modulus The calculation formula is:

[0048] in, For the first Volume fraction of the mineral components, For the first Bulk modulus of a single mineral skeleton.

[0049] Step S142: Determine the Hill average bulk modulus based on the Voigt average bulk modulus and the Reuss average bulk modulus; Specifically, Hill's average bulk modulus The calculation formula is:

[0050] in, Let Voigt be the average bulk modulus. Reussian average bulk modulus .

[0051] Step S143: Combine Hill's average bulk modulus, porosity, and pore fluid bulk modulus to determine the equivalent bulk modulus.

[0052] For example, in step S143, the equivalent bulk modulus is determined by combining the Hill average bulk modulus, porosity, and pore fluid bulk modulus, including: Step S31: Determine the Hill average bulk modulus as the mineral framework bulk modulus; Specifically, the bulk modulus of the current seabed sediment skeleton The value is Hill's average bulk modulus. As shown in the following formula:

[0053] Step S32, based on porosity, mineral framework bulk modulus, and Hertz-Mindlin contact theory, determines the bulk modulus of the dried framework, including:

[0054] in, It is a proportionality constant, with a range of values. It is closely related to the contact force and arrangement of particles. Take the median value of 0.2; Range of values , here Take the middle value of 4; Bulk modulus of the mineral framework; Step S33: Determine the high-frequency limiting effective bulk modulus based on porosity, pore fluid bulk modulus, mineral skeleton bulk modulus, and dry skeleton bulk modulus; Step S34: Determine the low-frequency limiting effective bulk modulus based on porosity, pore fluid bulk modulus, mineral skeleton bulk modulus, dry skeleton bulk modulus, and the Gassmann equation. Specifically, the equivalent bulk modulus calculated by the Gassmann equation can be regarded as the low-frequency limiting effective bulk modulus. As shown in the following formula:

[0055] in, The bulk modulus of the dried skeleton; The bulk modulus of the skeleton; Porosity; The value here represents the bulk modulus of the pore fluid. .

[0056] Step S35: Determine the equivalent bulk modulus based on the high-frequency limit effective bulk modulus and the low-frequency limit effective bulk modulus.

[0057] For example, in step S33, the high-frequency limiting effective bulk modulus is determined based on porosity, pore fluid bulk modulus, mineral framework bulk modulus, and dry framework bulk modulus, including: Step S331: Determine the volumetric compliance response of the solid mineral framework based on porosity and mineral framework bulk modulus; Step S332: The ratio of the dry skeleton bulk modulus to the mineral skeleton bulk modulus is determined as the dry skeleton correction term; Specifically, at high frequencies, the stress coupling characteristic term between the pore skeleton and the fluid in the Gassmann equation disappears under low-frequency conditions. Therefore, the high-frequency limiting effective bulk modulus is determined based on porosity, pore fluid bulk modulus, mineral skeleton bulk modulus, and dry skeleton bulk modulus. The volumetric compliance response characterizing a solid mineral framework reflects the compressive compliance contribution corresponding to the proportion of framework material in the total volume. It is a correction term for the stiffness of a dry framework relative to an ideal mineral matrix, used to describe the structural deviations that occur when the stiffness of a porous media framework is lower than that of a single mineral.

[0058] Step S333, determining the high-frequency limiting effective bulk modulus based on the volumetric compliance response, the skeleton correction term, and the pore fluid bulk modulus, includes:

[0059] in, For volumetric compliance response, Porosity Bulk modulus of the mineral framework; For skeleton correction items, The bulk modulus of the dried skeleton; This represents the bulk modulus of the pore fluid.

[0060] For example, the equivalent bulk modulus is as follows:

[0061] in, This is the low-frequency limiting effective bulk modulus. This is the high-frequency limiting effective bulk modulus. For the frequency of the sound signal, The relaxation frequency; Among them, relaxation frequency The calculation formula is:

[0062] For pore fluid dynamic viscosity, For pore fluid density, The pore size is the pore size.

[0063] For example, in step S15, the equivalent acoustic impedance of the current seabed sediment is determined based on the product of the real part of the equivalent bulk modulus and the equivalent density, including: The expression for equivalent acoustic impedance is:

[0064] in, To obtain the real part, Equivalent bulk modulus This is the equivalent density.

[0065] For example, the method for modeling and calculating the frequency response based on the acoustic impedance characteristics of seabed sediments is applied to underwater acoustic signals in the 20Hz to 10kHz frequency band.

[0066] The method provided in the embodiments of the present invention is referred to Figure 2 As shown, the acoustic signal propagates downwards from the seawater layer and is incident on the seabed sediment interface. Within the seawater layer, its acoustic characteristics are determined by the seawater acoustic impedance. ,in, The density of seawater, The speed of sound in seawater. When a sound wave strikes the sediment interface, it enters the underlying sandy sediment layer on the seabed, and its acoustic characteristics are determined by the equivalent acoustic impedance of the sediment. Characterization, in which, Equivalent density of sediment Let be the equivalent sound velocity of the sediment. Based on this, using the acoustic impedance characteristics of seabed sediments as a model, the expression for the equivalent acoustic impedance of seabed sediments is determined as follows: .

[0067] Furthermore, in an optional embodiment, the method provided by the embodiments of the present invention refers to... Figure 3 As shown: Step 1: Sediment sampling and porosity calculation.

[0068] Seabed sediment samples were collected, wrapped in an impermeable membrane, and the total volume of the samples was determined using the underwater displacement method. The sample was dried in an oven (105°C) for at least 24 hours, and the volume of solid particles in the dried sediment was determined using the helium method. The porosity of seabed sediment samples can then be calculated. .

[0069] Step 2: Determine the mineral species and mass fraction of the dry sediments by X-ray diffraction analysis.

[0070] Another sample of seabed sediment from the same area was taken, air-dried to prevent the decomposition of organic matter, and ground to a finer particle size of 200 mesh or less. X-ray diffraction analysis of the particles revealed a relatively simple mineral composition, consisting of solid quartz. The bulk modulus of the mineral framework was [not specified]. ,density Its mass fraction .

[0071] Step 3: Convert mineral mass fraction to volume fraction.

[0072] Mineral content fraction Convert to volume fraction .

[0073] Step 4: Calculation of Voigt's average bulk modulus.

[0074] Based on the bulk modulus of the mineral skeleton and its volume fraction The Voigt-mean bulk modulus is calculated based on the Voigt-mean (the upper limit of rigidity for mineral materials). .

[0075] Step 5: Calculation of Reuss's average bulk modulus.

[0076] Based on the bulk modulus of the mineral skeleton and its volume fraction The Reuss average bulk modulus was calculated based on the Reuss average (the upper limit of flexibility for mineral materials). .

[0077] Step 6: Calculation of Hill's average bulk modulus.

[0078] Based on Reuss's average bulk modulus and Voigt's average bulk modulus The Hill-mean bulk modulus was calculated using the Hill average (the arithmetic mean of Voigt and Reuss). .

[0079] Step 7: Calculation of the bulk modulus of the dried sediment skeleton.

[0080] The bulk modulus of the seabed sediment skeleton .

[0081] Based on the bulk modulus of the seabed sediment skeleton Using the Hertz-Mindlin contact theory, the bulk modulus of the dry sediment skeleton can be calculated. .

[0082] Step 8: Determination of the high-frequency limiting effective bulk modulus.

[0083] Based on the bulk modulus of the dry sediment skeleton and the bulk modulus of the seabed sediment skeleton The high-frequency limiting effective bulk modulus can be calculated. .

[0084] Step 9: Determination of the low-frequency limiting effective bulk modulus.

[0085] For water-saturated sediments, the equivalent bulk modulus calculated by the Gassmann equation can be considered as the low-frequency limiting effective bulk modulus for static fluids or fluids under low-frequency acoustic signals. .

[0086] Step 10: Determine the real part of the equivalent bulk modulus related to frequency.

[0087] As high-frequency acoustic signals act on the solid framework and pore fluids of sediments, the effective bulk modulus of the sediments is also affected by high frequencies. This is based on the low-frequency limiting effective bulk modulus. High-frequency limiting effective bulk modulus Harmony signal frequency By calculating at two frequency points, with acoustic signal frequencies of 100Hz and 500Hz, the real part of the frequency-dependent equivalent bulk modulus can be calculated. and .

[0088] Step 11: Calculation of equivalent acoustic impedance of sediment.

[0089] Based on pore fluid density Sediment particle density and sediment porosity The equivalent density of sediments can be calculated. .

[0090] Step 12: Determination of equivalent acoustic impedance.

[0091] Based on frequency-related equivalent bulk modulus and equivalent density The equivalent acoustic impedance of seabed sediments can be calculated. and The equivalent acoustic impedances at 100Hz and 500Hz are respectively and The trend is consistent with the change of the equivalent acoustic impedance frequency response diagram of seabed sediments, such as... Figure 4 As shown.

[0092] This invention proposes a method for modeling and calculating the frequency response of acoustic impedance characteristics of seabed sediments. This method, while ensuring the rigor of the physical model, enables dynamic calculation and prediction of sediment impedance over a wide frequency range. The beneficial effects of this invention are as follows: (1) Compared with the traditional impedance processing method based on constant values ​​or low frequency approximation, the present invention not only has clear frequency response characteristics, but also provides an adjustable parameter input interface, which can be quickly configured according to different sediment types and environmental conditions, and has a wider range of applications.

[0093] (2) The model parameters required by the present invention can be dynamically updated in combination with experimental measurements or measured data, thereby having good environmental adaptability and real-time application capability; (3) This invention is applicable to engineering and scientific research applications such as multi-layer interface acoustic propagation modeling, underwater target acoustic energy assessment, target response characteristic analysis and sediment parameter inversion, and has high practical value and promotion prospects.

[0094] It should be noted that the above figures are merely illustrative of the processes included in the method according to exemplary embodiments of the present invention, and are not intended to be limiting. It is readily understood that the processes shown in the above figures do not indicate or limit the temporal order of these processes. Furthermore, it is readily understood that these processes may, for example, be executed synchronously or asynchronously in multiple modules.

[0095] It should be noted that although several modules or units of the device for performing actions have been mentioned in the detailed description above, this division is not mandatory. In fact, according to embodiments of the present invention, the features and functions of two or more modules or units described above can be embodied in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided and embodied by multiple modules or units.

[0096] Figure 5 A schematic diagram of an electronic device suitable for implementing embodiments of the present invention is shown.

[0097] It should be noted that, Figure 5 The electronic device 1000 shown is merely an example and should not be construed as limiting the functionality and scope of use of the embodiments of the present invention.

[0098] like Figure 5 As shown, the electronic device 1000 includes a Central Processing Unit (CPU) 1001, which can perform various appropriate actions and processes based on programs stored in Read-Only Memory (ROM) 1002 or programs loaded from storage section 1008 into Random Access Memory (RAM) 1003. The RAM 1003 also stores various programs and data required for system operation. The CPU 1001, ROM 1002, and RAM 1003 are interconnected via a bus 1004. An Input / Output (I / O) interface 1005 is also connected to the bus 1004. Furthermore, the electronic device 1000 also includes an FPGA device and a System-on-a-Chip (SoC) device.

[0099] The following components are connected to I / O interface 1005: an input section 1006 including a keyboard, mouse, etc.; an output section 1007 including a cathode ray tube (CRT), liquid crystal display (LCD), etc., and speakers, etc.; a storage section 1008 including a hard disk, etc.; and a communication section 1009 including a network interface card such as a LAN (Local Area Network) card, modem, etc. The communication section 1009 performs communication processing via a network such as the Internet. A drive 1010 is also connected to I / O interface 1005 as needed. Removable media 1011, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., are installed on drive 1010 as needed so that computer programs read from them can be installed into storage section 1008 as needed.

[0100] For example, the aforementioned electronic device could be a host computer.

[0101] In particular, according to embodiments of the present invention, the processes described below with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program carried on a storage medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication section 1009, and / or installed from removable medium 1011. When the computer program is executed by central processing unit (CPU) 1001, it performs various functions defined in the system of this application.

[0102] Specifically, the aforementioned electronic devices can be airborne intelligent electronic devices, such as airborne video processing equipment.

[0103] It should be noted that the storage medium shown in the embodiments of the present invention can be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. A computer-readable storage medium can be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, optical fiber, portable compact disc read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In the present invention, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In the present invention, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, wherein computer-readable program code is carried. Such transmitted data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. The computer-readable signal medium can also be any storage medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the storage medium can be transmitted using any suitable medium, including but not limited to wireless, wired, etc., or any suitable combination thereof.

[0104] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0105] The units described in the embodiments of the present invention can be implemented in software or hardware, and the described units can also be located in a processor. The names of these units do not necessarily limit the specific unit itself.

[0106] It should be noted that, as another aspect, this application also provides a storage medium, which may be included in an electronic device or may exist independently without being assembled into the electronic device. The aforementioned storage medium carries one or more programs, which, when executed by an electronic device, cause the electronic device to perform the methods described in the following embodiments. For example, the electronic device may perform... Figure 1 The steps of the method shown.

[0107] In one embodiment, this application provides a computer program product including a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0108] Furthermore, the above figures are merely illustrative of the processes included in the method according to exemplary embodiments of the present invention, and are not intended to be limiting. It is readily understood that the processes shown in the above figures do not indicate or limit the temporal order of these processes. Additionally, it is readily understood that these processes may be executed synchronously or asynchronously, for example, in multiple modules.

[0109] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the claims.

[0110] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A method for modeling and calculating frequency response based on acoustic impedance properties of seafloor sediments, characterized by, The method comprises: obtaining the total volume and solid particle volume of the first seabed sediment sample, and obtaining the porosity of the first seabed sediment sample based on the total volume and solid particle volume of the first seabed sediment sample, and configuring the porosity of the first seabed sediment sample as the porosity of the current seabed sediment; performing X-ray diffraction analysis on the second seabed sediment sample to obtain the mineral composition and mass fraction of the second seabed sediment sample, and configuring the mineral composition and mass fraction of the second seabed sediment sample as the mineral composition and mass fraction of the current seabed sediment; wherein the first seabed sediment sample and the second seabed sediment sample are from the same area; determining the equivalent density of the current seabed sediment by combining the porosity, the mineral density corresponding to each mineral component, the mass fraction, and the Biot-Stoll dynamic density formula; determining the equivalent bulk modulus of the current seabed sediment by combining the mass fraction and the single-mineral skeleton bulk modulus corresponding to each mineral component; determining the equivalent acoustic impedance of the current seabed sediment based on the product of the real part of the equivalent bulk modulus and the equivalent density.

2. The method of claim 1, wherein, The method comprises: determining the volume fraction based on the mass fraction and the mineral density corresponding to each mineral component; wherein, is the mass fraction of the th mineral, is the mineral density of the th mineral, is the total number of mineral components. linearly weighting the mineral density corresponding to each mineral component according to the volume fraction to obtain the mineral skeleton density; determining the equivalent density by combining the porosity, the mineral skeleton density, and the Biot-Stoll dynamic density formula. wherein, is the porosity, is the sediment skeleton density, is the pore fluid density, is the inertial enhancement factor exhibited by the fluid when it is "dragged" by the solid at high frequencies.

3. The method of claim 2, wherein, The method comprises: determining the Voigt average bulk modulus and the Reuss average bulk modulus based on the volume fraction and the single-mineral skeleton bulk modulus; determining the Hill average bulk modulus based on the Voigt average bulk modulus and the Reuss average bulk modulus; determining the equivalent bulk modulus by combining the Hill average bulk modulus, the porosity, and the pore fluid bulk modulus.

4. The method of claim 3, wherein, The method comprises: determining the Hill average bulk modulus as the mineral skeleton bulk modulus; determining the dry skeleton bulk modulus based on the porosity, the mineral skeleton bulk modulus, and the Hertz-Mindlin contact theory. wherein, is a proportionality constant, having a value in the range , is closely related to the particle contact force and arrangement; has a value in the range ; is the mineral skeleton bulk modulus; determining the high-frequency limit effective bulk modulus based on the porosity, the pore fluid bulk modulus, the mineral skeleton bulk modulus, and the dry skeleton bulk modulus; determining the low-frequency limit effective bulk modulus based on the porosity, the pore fluid bulk modulus, the mineral skeleton bulk modulus, the dry skeleton bulk modulus, and the Gassmann equation; determining the equivalent bulk modulus based on the high-frequency limit effective bulk modulus and the low-frequency limit effective bulk modulus.

5. The method of claim 4, wherein, The method comprises: Determine a volumetric compliance response of the solid mineral skeleton based on the porosity and the mineral skeleton bulk modulus; Determine a dry skeleton correction term as a ratio of the dry skeleton bulk modulus and the mineral skeleton bulk modulus; Determine a high-frequency limit effective bulk modulus based on the volumetric compliance response, the dry skeleton correction term, and a pore fluid bulk modulus, including: wherein, is the bulk compliance response, is the porosity, is the mineral matrix bulk modulus; is the dry matrix correction term, is the dry matrix bulk modulus; is the pore fluid bulk modulus.

6. The method of claim 5, wherein, The equivalent bulk modulus, specifically: wherein, is the low frequency limit effective bulk modulus, is the high frequency limit effective bulk modulus, is the acoustic signal frequency, is the relaxation frequency; wherein the relaxation frequency is calculated by the formula: is the pore fluid dynamic viscosity, is the pore fluid density, is the pore size.

7. The method of claim 6, wherein, Determine an equivalent acoustic impedance of the current seafloor sediment based on a product of a real part of the equivalent bulk modulus and an equivalent density, including: An expression of the equivalent acoustic impedance is: wherein, is the real part, is the equivalent bulk modulus, is the equivalent density.

8. The method of claim 1, wherein, The method is applied to underwater acoustic signals in a frequency band of 20 Hz to 10 kHz.

9. A computer-readable storage medium, characterized in that, The computer readable storage medium includes a stored executable program, wherein the executable program, when executed, controls a device in which the storage medium is located to perform the method of any one of claims 1 to 8.

10. A computer program product, characterised in that, A computer program that, when executed by a processor, implements the method of any one of claims 1 to 8.

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