Underwater vehicle corrosion electric field simulation method based on equivalent electric dipole

Abstract

The invention discloses an equivalent electric dipole-based underwater vehicle corrosion electric field simulation method, and belongs to the technical field of underwater electric field measurement, and the method comprises the following steps: S1, constructing a multilayer seawater model; s2, constructing an underwater vehicle model, simulating a corrosion electric field of the underwater vehicle by adopting finite element software COMSOL, and calculating corrosion simulation electric field intensity at each sampling point; and S3, placing N electric dipoles in the seawater layer, performing inversion by using the corrosion simulation electric field intensity of the sampling point according to a current source electric type union vector Green function to obtain the electric dipole moment of the electric dipole at the position, performing iterative calculation on the position of the electric dipole and the electric dipole moment in combination with a fitness function, and outputting the optimal position of the electric dipole and the electric dipole moment. The invention provides a theoretical support and optimization method for corrosion electric field analysis and target detection of the underwater vehicle in a marine environment.

Description

Technical Field

[0001] This invention relates to a method for simulating the corrosion electric field of underwater vehicles based on equivalent electric dipoles, belonging to the field of underwater electric field measurement technology. Background Technology

[0002] Underwater vehicles are prone to generating corrosion currents and anti-corrosion currents in seawater due to electrochemical corrosion and anti-corrosion measures. These currents create a corrosion electric field in the seawater. This corrosion electric field is an important physical field that poses a serious threat to the electric field stealth performance and safety of underwater vehicles. Specifically, for example... Figure 1 As shown, the steel hull (anode) and copper alloy propeller (cathode) of an underwater vehicle form a macroscopic galvanic corrosion cell in seawater electrolyte. The hull, acting as the anode, undergoes a metal dissolution reaction, while the propeller, acting as the cathode, undergoes an oxygen reduction reaction. This process forms a corrosion current loop with a constant direction: the current flows from the steel hull through the seawater medium to the propeller, and then returns to the hull via the propeller shaft, forming a closed path. In addition, the protective current generated by the corrosion protection system returns to the system through the propeller shaft or the hull, forming another closed loop. Both loops generate corresponding corrosion electric fields. In the above scenario, the charge separation characteristics of the anode and cathode are equivalent to the positive and negative charge pairs of an electric dipole.

[0003] Numerical simulation methods for the corrosion electric field distribution of underwater vehicles have been studied by many researchers, including equivalent electric dipole simulation methods and numerical simulation methods such as the finite element method. The inversion method mainly includes the Tikhonov regularization method. This invention aims to provide a novel method for simulating the corrosion electric field of underwater vehicles. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a method for simulating the corrosion electric field of underwater vehicles based on an equivalent electric dipole. The consistency between the inversion results and the simulation results of the corrosion electric field of underwater vehicles demonstrates that it is feasible to replace the corrosion electric field of underwater vehicles with the equivalent electric dipole electric field.

[0005] The present invention achieves the above objectives by adopting the following technical solutions: A method for simulating the corrosion electric field of underwater vehicles based on equivalent electric dipoles includes the following steps: S1. Construct a multi-layered seawater model; S2. Construct an underwater vehicle model and use the finite element software COMSOL to simulate the corrosion electric field of the underwater vehicle, and calculate the corrosion simulation electric field intensity at each sampling point; S3. Place in the seawater layer NFor each electric dipole, the electric dipole moment at its location is obtained by inverting the electric field intensity of the corrosion simulation at the sampling point using the current source electric type dyadic Green's function. The position and electric dipole moment of the electric dipole are then iteratively calculated using the fitness function to output the optimal position and electric dipole moment of the electric dipole.

[0006] Furthermore, step S1 specifically includes: S1.1.1 Establish the xyz coordinate system, so that x shaft and y The axis is parallel to the sea surface. z The positive direction of the axis is perpendicular to the sea level and points to the seabed; S1.1.2 Above the seawater is an air layer, numbered 0. The seawater is divided into n layers along the Z-axis. The interface between the air layer and the first layer of seawater is located at... z At 0 = 0 m; the relative permittivity and conductivity of each layer are respectively , ( l =0,1,…,n).

[0007] Furthermore, step S2 specifically includes: S2.1 Construct a simulation model of the underwater vehicle; S2.2 Import the simulation model into COMSOL Multiphysics to simulate the corrosion electric field caused by macroscopic galvanic corrosion and the anti-corrosion system on the ship hull; S2.3 Take samples above and below the underwater vehicle. M The corrosion simulation electric field intensity was calculated at each sampling point. E .

[0008] Furthermore, step S2.1 specifically involves setting the origin of the coordinate system at the center of the hull. The hull consists of a cylindrical main body, a conning tower at the top of the hull, a propeller base composed of a cylinder and a hemispherical shell, propeller blades on the base, a propeller shaft connecting the base and the hull as a cylinder, a hemispherical shell at the bow, and two auxiliary anodes at the stern to simulate an impressed current cathodic protection system.

[0009] Furthermore, in step S2.2, the simulation method for the corrosion electric field caused by macroscopic galvanic corrosion is as follows: the current distribution in seawater and the corrosion reaction on the surface of the simulation model are simulated using the "cathode protection" module. The material of the hull is set in the "material" option, and the surfaces of the propeller and propeller shaft are set as electrode surfaces in the "boundary conditions" option. The electrode reaction that occurs on the surfaces of the two is set as the oxygen reduction process. The method for simulating the corrosion electric field caused by the anti-corrosion system is as follows: add a "reference electrode" potential in the "Model" option, and set the potential of the auxiliary anode relative to the potential of the reference electrode to simulate the cathodic protection system.

[0010] Furthermore, step S3 specifically includes: S3.1 at any position in the seawater layer Placed in any direction N A number of electric dipoles are distributed within a rotating ellipsoid based on the shape and dimensions of the ship's hull; among them... I Let be the current in the electric dipole, and divide each electric dipole into multiple segments, each segment being Δl. I Δ l It is a current element; S3.2 The electric field strength generated by the electric dipole at the field point is simulated using the current source electric type dyadic Green's function: (1) S3.3 Based on the electric dipole moment of the electric dipole and equation (1), we obtain: (2) E correspond M The simulated electric field strength at each sampling point is 3 M A ×1 matrix; P correspond N The electric dipole moment of each electric dipole is 3 N A ×1 matrix; G 3 M ×3 N 1-order matrix; S3.4 Each electric dipole obtains a matrix based on its current position. G The simulated electric field strength at this location is known. E The electric dipole moment is solved using the least squares method according to equation (2). P The solution is expressed as: (3) in, for G The generalized inverse matrix; S3.5 Iteratively update the position and electric dipole moment of the electric dipole according to the fitness function to solve for the optimal position and electric dipole moment of the electric dipole.

[0011] Furthermore, step S3.5 specifically includes: S3.5.1 Given the initial position of each electric dipole Initial velocity Initial individual optimal solution , ; Each electric dipole has a coefficient matrix G based on its current position. The electric dipole moment corresponding to the current position of the electric dipole is calculated using equation (3).P According to the coefficient matrix G With electric dipole moment P The product is used to calculate the fitted electric field strength; The fitness value is calculated using the fitness function, and the position of the electric dipole with the smallest fitness value is selected as the initial global optimum. The fitness function is the relative error between the simulated electric field strength and the fitted electric field strength, i.e.: (4) S3.5.2 Update the velocity and position of the electric dipole. After each update, calculate the fitness value using equation (4). ; S3.5.3 Comparison and ,like < ,but ;otherwise, The previous value is retained to update the individual optimal solution; The individual optimal solution with the smallest fitness value among all electric dipoles is selected as the global optimal solution for this update. ; After the update is completed, the next iteration is implemented until the maximum number of iterations is reached, and the position and electric dipole moment of the electric dipole are output.

[0012] Furthermore, in step S3.5.2, the velocity update formula for the electric dipole is: (5) In the formula, For the first k Electric dipole during the next iteration i The d Dimensional flight speed; For the first k -1st iteration electric dipole i The d Dimensional position; a 1. a 2 is the learning factor. b 1. b 2 is a random number in the interval [0,1]. , For the first k The electric dipole at the -1st iteration d The individual optimal solution and the global optimal solution at a specific position; Inertial weights; The position update formula for an electric dipole is: (6) In the formula, For the first k Electric dipole during the next iteration i The d Dimensional position.

[0013] The beneficial effects of the present invention include, but are not limited to: The present invention provides a method for simulating the corrosion electric field of underwater vehicles based on equivalent electric dipoles. This invention is based on the corrosion electric field distribution of underwater vehicles obtained by COMSOL simulation. It uses the dyadic Green's function of layered medium to simulate the corrosion electric field generated by the equivalent DC power supply. The dyadic Green's function is combined with an iterative update algorithm to invert the position and intensity of the equivalent electric dipole, thus providing theoretical support and optimization methods for corrosion electric field analysis and target detection of underwater vehicles in marine environments.

[0014] Calculations revealed that the inversion results of the corrosion electric field become increasingly accurate as the number of equivalent electric dipoles increases. The consistency between the inversion results and the simulation results of the corrosion electric field of underwater vehicles demonstrates that it is feasible to replace the corrosion electric field of underwater vehicles with the equivalent electric dipole electric field. Attached Figure Description

[0015] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of corrosion current and corrosion protection current; Figure 2 This is a diagram of a multi-layered seawater model; Figure 3 A simulation model diagram of an underwater vehicle; Figure 4 A comparison diagram of the electric dipole electric fields obtained by the three algorithms; Figure 5 This is a comparison diagram of the electric field generated by the equivalent electric dipole on sampling line 1 and the simulated electric field; Figure 6 for y =40m cross-section of electric field distribution generated by 10 equivalent electric dipoles; Figure 7 for y Corrosion electric field distribution diagram from COMSOL simulation of a 40m profile. Detailed Implementation

[0016] The present invention will be further described in detail below. However, it should be noted that the following specific embodiments are merely exemplary examples of the invention, and the scope of protection of the invention is not limited thereto. The scope of protection of the invention is defined only by the claims. It will be apparent to those skilled in the art that various other modifications and substitutions can be made to the embodiments of the invention within the scope of protection defined by the claims, and the same technical effects can still be achieved, thus achieving the ultimate technical objective of the invention.

[0017] The method for simulating the corrosion electric field of underwater vehicles based on equivalent electric dipoles provided by this invention includes the following steps: S1. Construct a multi-layered seawater model; Furthermore, such as Figure 2 As shown, step S1 specifically includes: S1.1.1 Establish the xyz coordinate system, so that x shaft and y The axis is parallel to the sea surface. z The positive direction of the axis is perpendicular to the sea level and points to the seabed; S1.1.2 Considering the actual marine environment, a multi-layer seawater model is constructed to calculate the corrosion electric field of the equivalent electric dipole. Above the seawater is an air layer, numbered 0. The seawater is divided into n layers along the Z-axis. The interface between the air layer and the first layer of seawater is located at... z At 0 = 0 m; the relative permittivity and conductivity of each layer are respectively , ( l =0,1,…,n); the first n Below the seawater layer is a sedimentary layer.

[0018] S2. Construct an underwater vehicle model and use the finite element software COMSOL to simulate the corrosion electric field of the underwater vehicle, and calculate the corrosion simulation electric field intensity at each sampling point; Furthermore, step S2 specifically includes: S2.1 as Figure 3 As shown in the figure, an underwater vehicle simulation model is constructed; Furthermore, step S2.1 specifically includes: The origin of the coordinate system is set at the center of the hull. The hull consists of a cylindrical main body, a conning tower at the top of the hull, a propeller base consisting of a cylinder and a hemispherical shell, a propeller blade on the base, a propeller shaft connecting the base and the hull that is cylindrical, a hemispherical shell at the bow, and two auxiliary anodes at the stern to simulate an impressed current cathodic protection system.

[0019] S2.2 Import the simulation model into COMSOL Multiphysics to simulate the corrosion electric field caused by macroscopic galvanic corrosion and the anti-corrosion system on the ship hull; Furthermore, in step S2.2, the simulation method for the corrosion electric field caused by macroscopic galvanic corrosion is as follows: the current distribution in seawater electrolyte and the corrosion reaction on the simulation model surface are simulated using the "cathode protection" module. The material of the hull is set in the "material" option, and the surfaces of the propeller and propeller shaft are set as electrode surfaces in the "boundary conditions" option. The electrode reaction occurring on the two surfaces is set as the oxygen reduction process. The method for simulating the corrosion electric field caused by the anti-corrosion system is as follows: add a "reference electrode" potential in the "Model" option, and set the potential of the auxiliary anode relative to the potential of the reference electrode to simulate the cathodic protection system.

[0020] S2.3 Take samples above and below the underwater vehicle. M The corrosion simulation electric field intensity was calculated at each sampling point. E Typically, along the top and bottom of the underwater vehicle... y Several sampling lines are laid out in different directions, such as Figure 2 As shown, sampling points are taken on each sampling line, and the three-component electric field is obtained by COMSOL simulation.

[0021] S3. In the inversion of the corrosion electric field of underwater vehicles, the optimization of the equivalent electric dipole array model simplifies to an optimization problem of the electric dipole position and electric dipole moment. Therefore, placing [the model] in the seawater layer... N For each electric dipole, the electric dipole moment at its location is obtained by inverting the electric field intensity of the corrosion simulation at the sampling point using the current source electric type dyadic Green's function. The position and electric dipole moment of the electric dipole are then iteratively calculated using the fitness function to output the optimal position and electric dipole moment of the electric dipole.

[0022] Furthermore, step S3 specifically includes: S3.1 Placed at any location in the seawater layer in any direction. N A number of electric dipoles are distributed within a rotating ellipsoid based on the shape and dimensions of the ship's hull; among them... I Let be the current in the electric dipole, and divide each electric dipole into multiple segments, each segment being Δl. I Δ l It is a current element; S3.2 uses a current source type dyadic Green's function. The electric field strength generated by the simulated electric dipole at the field point is: (1) The current source type dyadic Green's function is expressed in the following form:

[0023] In the formula, , , Let x, y, and z represent the components of the electric field intensity produced by a unit electric dipole in the x-direction in the x, y, and z directions, respectively. , , Let x, y, and z represent the components of the electric field intensity produced by a unit electric dipole in the y direction in the x, y, and z directions, respectively. , , These represent the components of the electric field intensity produced by a unit electric dipole in the z direction in the x, y, and z directions, respectively. The Green's function is determined by the position of the electric dipole and is calculated according to existing formulas.

[0024] S3.3 Based on the electric dipole moment of the electric dipole and equation (1), we obtain: (2) E correspond M The three-component data of the simulated electric field intensity at each sampling point are 3 M A ×1 matrix; P correspond N The three components of the electric dipole moment of each electric dipole are 3. N A ×1 matrix; G 3 M ×3 N 1-order matrix; S3.4 Each electric dipole obtains a matrix based on its current position. G The simulated electric field strength at this location is known. E Due to the number of sampling points M Much greater than the number of electric dipoles N Therefore, solving for the electric dipole moment based on the known simulated electric field strength is a solution to the overdetermined equation; thus, the electric dipole moment is solved using the least squares method according to equation (2). P The solution is expressed as: (3) in, for G The generalized inverse matrix; S3.5 Iteratively update the position and electric dipole moment of the electric dipole according to the fitness function to solve for the optimal position and electric dipole moment of the electric dipole.

[0025] Furthermore, step S3.5 specifically includes: S3.5.1 Given the initial position of each electric dipole Initial velocity Initial individual optimal solution , ; Each electric dipole has a coefficient matrix G based on its current position. The electric dipole moment corresponding to the current position of the electric dipole is calculated using equation (3). P According to the coefficient matrix G With electric dipole moment P The product of these factors yields the fitted electric field strength. In this step, the electric dipole moment... P It was obtained by solving using the least squares method, so G·P and E There will be errors, and the next step is to reduce these errors through updates and iterations.

[0026] Therefore, the fitness value is calculated using a fitness function, and the position of the electric dipole with the smallest fitness value is selected as the initial global optimum. The fitness function is the relative error between the simulated electric field strength and the fitted electric field strength, i.e.: (4) S3.5.2 Update the velocity and position of the electric dipole. After each update, calculate the fitness value using equation (4). ; Furthermore, in step S3.5.2, the velocity update formula for the electric dipole is: (5) In the formula, For the first k Electric dipole during the next iteration i The d Dimensional flight speed; For the first k -1st iteration electric dipole i The d Dimensional position; a 1. a 2 is the learning factor, and we take... a 1= a 2≈2; b 1. b 2 is a random number in the interval [0,1]. , For the first k The electric dipole at the -1st iteration d The individual optimal solution and the global optimal solution at a specific position; The inertial weight can be a fixed value or dynamically adjusted (e.g., linearly decreasing within a certain upper and lower limit range). This invention uses... , KThe maximum number of iterations is 800. In this invention, the total number of electric dipoles is 100, and the maximum number of iterations is 800.

[0027] The position update formula for an electric dipole is: (6) In the formula, For the first k Electric dipole during the next iteration i The d Dimensional position.

[0028] S3.5.3 Comparison and ,like < ,but ;otherwise, The previous value is retained to update the individual optimal solution; The individual optimal solution with the smallest fitness value among all electric dipoles is selected as the global optimal solution for this update. ; After the update is completed, the next iteration is implemented until the maximum number of iterations is reached, and the position and electric dipole moment of the electric dipole are output.

[0029] The update and iteration method employed in this invention finds the optimal solution through collaboration and information sharing among individuals within a group. D In the dimensional target search space, the total population is I Each particle in the swarm has a position vector and a velocity vector, representing its search state in the solution space. The position vector indicates the solution at its current position, and the velocity vector indicates the direction and speed of the particle's movement during the search. Each particle also possesses a memory function, remembering the optimal position it has found. The dimension of the target search space... D and N The relationship is D =3 N At each step of the algorithm's implementation, each particle searches in space and obtains its own optimal solution. ( i =1,2,…, I ; d =1,2,…, D The individual optimal solutions are shared with other particles in the swarm, and the current global optimal solution of the entire particle swarm is obtained based on the current individual optimal solutions of all particles. Each particle in the swarm continuously changes its position and velocity based on its current individual optimal solution and the global optimal solution, updating the individual optimal solution and the global optimal solution, until the maximum number of iterations is reached or the particle converges to the optimal position.

[0030] The following specific embodiments will further illustrate the underwater vehicle corrosion electric field simulation method based on equivalent electric dipoles provided by the present invention.

[0031] Example 1: To verify the correctness of the results of the dyadic Green's function and COMSOL simulation, this embodiment calculates the electric field generated by a DC electric dipole in infinitely deep seawater and compares it with the calculation results of the traditional image method.

[0032] When using the dyadic Green's function for simulation calculations, the value is taken as... The extremely low frequencies of Hz are treated as equivalent to DC. The model used is a two-layer dielectric model, with the first layer being air and its conductivity being... =0, the second medium is infinitely deep seawater, its conductivity is 0. =4S·m -1 .along x An electric dipole placed along its axis is located at a water depth of 150m, with coordinates (0, 0, 150). The magnitude of the electric dipole moment is... p = I Δ l =100A·m.

[0033] Figure 4 Given y =0m、 z =225m along x Two non-zero components of the electric field intensity in the axial direction within the range of -200m to 200m E x and E z Field point position coordinates x The changing relationship.

[0034] Depend on Figure 4 It can be seen that the calculation results of the dyadic Green's function, COMSOL, and mirror method are completely consistent, demonstrating the correctness of both the dyadic Green's function and COMSOL algorithms. Figure 4 From a, we can know that E x Relative to the field point position coordinates x =0 is symmetrical about left and right, in x Its amplitude reaches its maximum value at =0. (From...) Figure 4 b indicates that... E z Relative to the field point position coordinates x =0 is antisymmetric, in x At point =0, its amplitude is 0. As the field point moves further away, E x and E zAll are close to 0.

[0035] Example 2: (2.1) Model Construction: In this embodiment, the corrosion electric field of the underwater vehicle is simulated using the finite element software COMSOL as the measurement value to be inverted. The hull is 50 m long, and the main body of the hull is cylindrical with a diameter of 6 m. The sail extends 3.5 m above the top of the hull, is 10 m long, and has a thickness of 2 m. The center of the sail is located at... x =3 m. The propeller base consists of a cylinder 1.1 m long and 0.4 m in radius and a hemispherical shell with a radius of 0.4 m. There are four propeller blades on the base. The propeller shaft connecting the base to the hull is a cylinder with a radius and length of 0.2 m. The bow section is a hemispherical shell with a radius of 3 m. Two auxiliary anodes are located at the stern of the submarine. x =17 m is used to simulate an impressed current cathodic protection system.

[0036] The above model was imported into COMSOL Multiphysics, and the "Cathode Protection" module was used to simulate the current distribution in the electrolyte and the corrosion reaction on the metal surface. In the "Materials" option, a nickel-aluminum bronze (NAB) alloy was selected for the propeller, and a 625 alloy was selected for the propeller shaft. In the "Boundary Conditions" option, the surfaces of the propeller and propeller shaft were set as electrode surfaces, and the electrode reaction occurring on these surfaces was set as an oxygen reduction process. The limiting current density for the electrode kinetics expression during the oxygen reduction process was set to 5 A·m. -2 In the "Model" options, add a "Reference Electrode" node (potential 0V), and then set the electrode potential of the auxiliary anode relative to the reference electrode to -850mV to simulate a cathodic protection system. Use the default "Insulation" condition for all boundaries of the remaining portion of the underwater vehicle surface. To simulate the infinite extension of the ocean, use the "Infinite Electrolyte" condition for the outer boundary of the electrolyte domain.

[0037] In the simulation, the seawater was assumed to be homogeneous and the effects of the air layer and sediment layer were ignored. The conductivity of the seawater was taken as 4 S·m. -1 Along the top and bottom of the underwater vehicle y Two sampling lines are deployed in each direction. The three-component electric field obtained by COMSOL simulation on each sampling line is used as the training set. The number of sampling points on each sampling line is 41. The position of sampling line 1 is... x =-10 m、 z =23 m, the location of sampling line 2 is x =-10 m、 z =-17 m, the location of sampling line 3 is x =10 m z=-17 m, the location of sampling line 4 is x =10 m z =23 m, each sampling line is at y The directional sampling range is -100m to 100m.

[0038] (2.2) Corrosion electric field inversion: When inverting the corrosion electric field of an underwater vehicle, the distribution range of electric dipoles is restricted to a rotating ellipsoid with a semi-major axis of 25 m and a semi-minor axis of 3 m, based on the hull size. Assuming the number of equivalent electric dipoles is 1, 5, and 10 respectively, the positions and electric dipole moments of the equivalent electric dipoles in the three cases are obtained by inversion using the dyadic Green's function method and particle swarm optimization algorithm, as shown in Tables 1, 2, and 3, respectively, by comparing Tables 1-3. It can be seen that as the number increases, the distribution of the equivalent electric dipoles more closely approximates the size and position of the underwater vehicle.

[0039]

[0040]

[0041]

[0042] Figure 5 The three components of the corrosion electric field on sampling line 1 calculated using the dyadic Green's function for three different numbers of electric dipoles are compared with the original simulation data.

[0043] Depend on Figure 5 It can be seen that, E x and E z All relative to y =0 is symmetric in the plane, y The amplitude value reaches its maximum at the point =0. E y Compared to y =0 plane antisymmetry, in y =0 E y =0. (Also from...) Figure 5 It can be seen that the electric field generated by multiple electric dipoles obtained from the simulation electric field inversion is consistent with the overall trend of the simulation electric field. When the number of equivalent electric dipoles increases to 10, the corrosion electric field generated by the electric dipoles highly coincides with the simulation electric field curve, and the maximum amplitude is at... E x The relative error is 2.0%. E y The relative error is 1.6%.E z The relative error is 0.2%. This shows that the inversion result of the corrosion electric field becomes increasingly accurate as the number of equivalent electric dipoles increases. However, once the number of equivalent electric dipoles reaches a certain threshold, the relative error does not improve significantly.

[0044] Figure 6 Given y The electric field distribution generated by 10 equivalent electric dipoles was calculated using the dyadic Green's function on a 40m profile. Figure 7 The distribution of the corrosion electric field of an underwater vehicle simulated using COMSOL on the same cross-section is presented. (Comparison) Figure 6 and Figure 7 The distribution of the electric field generated by the 10 equivalent electric dipoles is consistent with the actual distribution of the corrosion electric field of the underwater vehicle, which further illustrates the accuracy of the inversion results and the feasibility of using the equivalent electric dipole electric field to replace the corrosion electric field of the underwater vehicle.

[0045] The above specific embodiments should not be construed as limiting the scope of protection of the present invention. For those skilled in the art, any alternative improvements or modifications made to the embodiments of the present invention shall fall within the scope of protection of the present invention.

[0046] Any aspects of this invention not described in detail are well-known to those skilled in the art.

Claims

1. A method for simulating the corrosion electric field of underwater vehicles based on equivalent electric dipoles, characterized in that, Includes the following steps: S1. Construct a multi-layered seawater model; S2. Construct an underwater vehicle model and use the finite element software COMSOL to simulate the corrosion electric field of the underwater vehicle, and calculate the corrosion simulation electric field intensity at each sampling point; S3. Place in the seawater layer N For each electric dipole, the electric dipole moment at its location is obtained by inverting the electric field intensity of the corrosion simulation at the sampling point using the current source electric type dyadic Green's function. The position and electric dipole moment of the electric dipole are then iteratively calculated using the fitness function to output the optimal position and electric dipole moment of the electric dipole.

2. The method for simulating the corrosion electric field of underwater vehicles based on equivalent electric dipoles according to claim 1, characterized in that, Step S1 is as follows: S1.1.1 Establish the xyz coordinate system, so that x shaft and y The axis is parallel to the sea surface. z The positive direction of the axis is perpendicular to the sea level and points to the seabed; S1.1.2 Above the seawater is an air layer, numbered 0. The seawater is divided into n layers along the Z-axis. The interface between the air layer and the first layer of seawater is located at... z At 0 = 0 m; the relative permittivity and conductivity of each layer are respectively , ( l =0,1,…,n).

3. The method for simulating the corrosion electric field of underwater vehicles based on equivalent electric dipoles according to claim 1, characterized in that, Step S2 is as follows: S2.1 Construct a simulation model of the underwater vehicle; S2.2 Import the simulation model into COMSOL Multiphysics to simulate the corrosion electric field caused by macroscopic galvanic corrosion and the anti-corrosion system on the ship hull; S2.3 Take samples above and below the underwater vehicle. M The corrosion simulation electric field intensity was calculated at each sampling point. E .

4. The method for simulating the corrosion electric field of underwater vehicles based on equivalent electric dipoles according to claim 3, characterized in that, In step S2.2, the simulation method for the corrosion electric field caused by macroscopic galvanic corrosion is as follows: use the "cathode protection" module to simulate the current distribution in seawater and the corrosion reaction on the surface of the simulation model. In the "material" option, set the material of the hull. In the "boundary conditions" option, set the surfaces of the propeller and propeller shaft as electrode surfaces. Set the electrode reaction that occurs on the surfaces of the two as the oxygen reduction process. The method for simulating the corrosion electric field caused by the anti-corrosion system is as follows: add a "reference electrode" potential in the "Model" option, and set the potential of the auxiliary anode relative to the potential of the reference electrode to simulate the cathodic protection system.

5. The method for simulating the corrosion electric field of underwater vehicles based on equivalent electric dipoles according to claim 1, characterized in that, Step S3 is as follows: S3.1 at any position in the seawater layer Placed in any direction N A number of electric dipoles are distributed within a rotating ellipsoid based on the shape and dimensions of the ship's hull; among them... I Let be the current in the electric dipole, and divide each electric dipole into multiple segments, each segment being Δl. I Δ l It is a current element; S3.2 uses a current source type dyadic Green's function. Simulated electric dipole at the field point The electric field strength generated at that location is: (1) S3.3 Based on the electric dipole moment of the electric dipole And from equation (1), we get: (2) E correspond M The simulated electric field strength at each sampling point is 3 M A ×1 matrix; P correspond N The electric dipole moment of each electric dipole is 3 N A ×1 matrix; G 3 M ×3 N 1-order matrix; S3.4 Each electric dipole obtains a matrix based on its current position. G The simulated electric field strength at this location is known. E The electric dipole moment is solved using the least squares method according to equation (2). P The solution is expressed as: (3) in, for G The generalized inverse matrix; S3.5 Iteratively update the position and electric dipole moment of the electric dipole according to the fitness function to solve for the optimal position and electric dipole moment of the electric dipole.

6. The method for simulating the corrosion electric field of underwater vehicles based on equivalent electric dipoles according to claim 5, characterized in that, Step S3.5 specifically includes: S3.5.1 Given the initial position of each electric dipole Initial velocity Initial individual optimal solution ; Each electric dipole has a coefficient matrix G based on its current position. The electric dipole moment corresponding to the current position of the electric dipole is calculated using equation (3). P According to the coefficient matrix G With electric dipole moment P The product is used to calculate the fitted electric field strength; The fitness value is calculated using the fitness function, and the position of the electric dipole with the smallest fitness value is selected as the initial global optimum. The fitness function is the relative error between the simulated electric field strength and the fitted electric field strength, i.e.: (4) S3.5.2 Update the velocity and position of the electric dipole. After each update, calculate the fitness value using equation (4). ; S3.5.3 Comparison and ,like < ,but ; otherwise, The previous value is retained to update the individual optimal solution; The individual optimal solution with the smallest fitness value among all electric dipoles is selected as the global optimal solution for this update. ; After the update is completed, the next iteration is implemented until the maximum number of iterations is reached, and the position and electric dipole moment of the electric dipole are output.

7. The method for simulating the corrosion electric field of underwater vehicles based on equivalent electric dipoles according to claim 6, characterized in that, In step S3.5.2, the velocity update formula for the electric dipole is: (5) In the formula, For the first k Electric dipole during the next iteration i The d Dimensional flight speed; For the first k -1st iteration electric dipole i The d Dimensional position; a 1. a 2 is the learning factor. b 1. b 2 is a random number in the interval [0,1]. , For the first k The electric dipole at the -1st iteration d The individual optimal solution and the global optimal solution at a specific position; Inertial weights; The position update formula for an electric dipole is: (6) In the formula, For the first k Electric dipole during the next iteration i The d Dimensional position.

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