A method for assessing local structural damage of underwater explosion hull

Abstract

The present invention provides a method for assessing the damage of a local structure of a hull caused by an underwater explosion, and relates to the technical field of data processing. The method comprises: obtaining underwater explosion working condition parameters, the working condition parameters comprising: charge TNT equivalent and explosion position; obtaining hull structure data; calculating the initial damage degree of the hull under the action of the underwater explosion based on the working condition parameters and the hull structure data, based on an equivalent simulation method; determining a hull area with an initial damage degree greater than a preset damage degree as a key local area; calculating the precise damage degree of the key local area of ​​the hull under the action of the underwater explosion based on the working condition parameters and the structural data of the key local area, based on a finite element analysis method. The present invention can perform a fine finite element analysis on a key local area with a large initial damage degree, improve the refinement and accuracy of the local structure damage assessment, and does not need to simulate the entire hull each time, thereby reducing the complexity and time consumption of the simulation.

Description

Technical Field

[0001] The invention relates to the technical field of data processing, and in particular to a method and system for evaluating damage to a local structure of an underwater explosion hull. Background Art

[0002] The explosion of underwater weapons at close range can cause large deformation of the local structure of the ship, thus affecting the safety of the crew. By assessing the damage, we can understand the ship's explosion resistance in the event of an underwater explosion, providing important input for the rapid assessment of personnel injuries and rescue and protection.

[0003] Existing technologies often directly obtain structural deformation through finite element simulation. The simulation model of the hull structure is usually quite complex. Simulating the entire hull increases the complexity and time-consuming nature of the simulation. The evaluation takes a long time and is costly, and it is difficult to adapt to the needs of rapid evaluation. Summary of the invention

[0004] In order to solve the technical problems that the existing technology often directly obtains structural deformation through finite element simulation, the simulation model of the hull structure is usually quite complex, and the simulation of the entire hull increases the complexity and time-consumingness of the simulation, the evaluation takes a long time, the cost is high, and it is difficult to adapt to the needs of rapid evaluation, the present invention provides a method and system for evaluating the local structural damage of an underwater explosion hull.

[0005] The technical solution provided by the embodiment of the present invention is as follows:

[0006] First aspect

[0007] An embodiment of the present invention provides a method for assessing damage to a local structure of an underwater explosion hull, comprising:

[0008] S1: Acquire underwater explosion working condition parameters, wherein the working condition parameters include: TNT equivalent of charge and explosion position;

[0009] S2: Acquire hull structure data;

[0010] S3: Calculating the initial damage degree of the hull under the underwater explosion based on the working condition parameters and the hull structure data and based on the equivalent simulation method;

[0011] S4: The hull area with the initial damage degree greater than the preset damage degree is determined as the key local area;

[0012] S5: According to the operating parameters and the structural data of the key local area, based on the finite element analysis method, the precise degree of damage to the key local area of ​​the hull under the action of the underwater explosion is calculated.

[0013] Second aspect

[0014] An embodiment of the present invention provides a system for assessing damage to a local structure of an underwater explosion hull, comprising:

[0015] processor;

[0016] A memory having computer-readable instructions stored thereon, wherein when the computer-readable instructions are executed by the processor, the method for assessing damage to a local structure of a hull caused by an underwater explosion as described in the first aspect is implemented.

[0017] The third aspect

[0018] An embodiment of the present invention provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the method for assessing local structural damage of an underwater explosion hull as described in the first aspect is implemented.

[0019] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include at least:

[0020] (1) In the present invention, based on the explosion mechanics theory and the typical structure of the hull, according to the working condition parameters, the equivalent plate thickness of the plate frame and the equivalent stiffness of the plate frame, the initial damage degree of the hull structure under the action of the underwater explosion is calculated quickly and accurately, which can provide a reference for the rapid assessment of personnel injuries and rescue and protection.

[0021] (2) In the present invention, the hull area with a preliminary damage degree greater than the preset damage degree is determined as the key local area, and then a detailed finite element analysis is performed on the key local area to improve the refinement and accuracy of the local structural damage assessment. There is no need to simulate the entire hull every time, which reduces the complexity and time consumption of the simulation, shortens the assessment time, and can meet the needs of rapid assessment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 A schematic flow chart of a method for assessing damage to a local structure of a hull caused by an underwater explosion provided by an embodiment of the present invention;

[0024] Figure 2 A schematic diagram of a method for assessing damage to a local structure of a hull caused by an underwater explosion provided by an embodiment of the present invention;

[0025] Figure 3 A schematic structural diagram of a system for assessing damage to a local structure of an underwater explosion hull provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0027] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the word "example" is intended to present the concept in a specific way. In addition, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or it can be either of the two.

[0028] In the embodiments of the present invention, "image" and "picture" can sometimes be used interchangeably. It should be noted that when the difference between them is not emphasized, the meanings they intend to express are the same. "of", "corresponding, relevant" and "corresponding" can sometimes be used interchangeably. It should be noted that when the difference between them is not emphasized, the meanings they intend to express are the same.

[0029] In the embodiments of the present invention, sometimes the subscripts such as W 1 It may be written in non-subscript form such as W1. When the difference is not emphasized, the meaning is the same.

[0030] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0031] Reference Manual Attached Figure 1 , showing a flow chart of a method for assessing local structural damage of an underwater explosion hull provided by an embodiment of the present invention.

[0032] Reference Manual Attached Figure 2 , showing a schematic structural diagram of a method for assessing local structural damage of an underwater explosion hull provided by an embodiment of the present invention.

[0033] The embodiment of the present invention provides a method for assessing the damage of a local structure of a hull caused by an underwater explosion. The method can be implemented by a device for assessing the damage of a local structure of a hull caused by an underwater explosion. The device for assessing the damage of a local structure of a hull caused by an underwater explosion can be a terminal or a server. The processing flow of the method for assessing the damage of a local structure of a hull caused by an underwater explosion can include the following steps:

[0034] S1: Obtain underwater explosion condition parameters.

[0035] Among them, the operating parameters include: TNT equivalent of charge and explosion position.

[0036] S2: Obtain hull structure data.

[0037] The hull structure data include: the length, width, thickness of the frame, the elastic modulus of the material used for the frame, the cross-sectional shape and size of the longitudinal reinforcement and the transverse reinforcement, the spacing between the longitudinal reinforcement and the transverse reinforcement, the cross-sectional moment of inertia of the frame, and the position and layer information of the frame.

[0038] S3: According to the working parameters and hull structure data, based on the equivalent simulation method, calculate the initial damage degree of the hull under the action of underwater explosion.

[0039] In a possible implementation, S3 specifically includes sub-steps S301 to S303:

[0040] S301: Calculate the equivalent plate thickness of the plate rack according to the structural data of the plate rack.

[0041] Optionally, the equivalent plate thickness of the plate rack is specifically:

[0042]

[0043] Among them, h represents the equivalent plate thickness of the plate frame, I represents the cross-sectional inertia moment of the reinforced structure, i represents the number of reinforced structures in the x direction, j represents the number of reinforced structures in the y direction, x and y represent the rotation axis directions of the reinforced structures, a represents half of the width of the plate frame, and b represents half of the length of the plate frame.

[0044] In the present invention, the calculation of the equivalent plate thickness of the plate frame not only considers the cross-sectional area and spacing of the reinforcement, but also includes the section moment of inertia of the reinforced structure. The addition of the section moment of inertia can more comprehensively consider the bearing capacity of the plate frame structure, because the moment of inertia can reflect the bending performance of the structure in different directions, including longitudinal and transverse directions. At the same time, the reinforcement structure in the hull structure is usually arranged in different directions, not just reinforcement in a single direction. This method takes into account the contribution of the reinforcement structures in different directions to the overall structural strength, which is more in line with the complexity of the actual hull structure.

[0045] S302: Calculate the equivalent stiffness of the panel frame according to the structural data of the panel frame.

[0046] Optionally, the equivalent stiffness of the plate frame is specifically:

[0047]

[0048] Wherein, K represents the equivalent stiffness of the plate frame, E represents the elastic modulus of the hull material, μ represents the Poisson's ratio, a represents half of the width of the plate frame, and b represents half of the length of the plate frame.

[0049] In the present invention, the specific cross-sectional shape and size of the reinforcement structure do not need to be considered, and the width and length of the frame are directly used, which simplifies the calculation and does not require detailed reinforcement structure data. This method can more directly and concisely calculate the equivalent stiffness of the frame, thereby more comprehensively evaluating the local deformation of the frame under the action of underwater explosion.

[0050] S303: According to the working condition parameters, the equivalent plate thickness of the plate frame and the equivalent stiffness of the plate frame, based on the equivalent simulation method, the initial damage degree of the hull under the action of the underwater explosion is calculated.

[0051] Optionally, the damaged major axis length of the hull under the action of the underwater explosion is calculated according to the following formula, and the initial damage degree is quantified by the damaged major axis length:

[0052]

[0053] Among them, L p It represents the length of the damaged major axis, which is used to characterize the initial degree of damage. W represents the TNT equivalent of the charge. h represents the equivalent plate thickness of the plate frame. K represents the equivalent stiffness of the plate frame.

[0054] In the present invention, based on the explosion mechanics theory and the typical hull structure, the TNT equivalent of the charge, the equivalent plate thickness and the equivalent stiffness of the plate frame are comprehensively taken into consideration, and the destruction range of the plate frame under the action of underwater explosion is calculated. The initial damage degree of the hull structure under the action of underwater explosion can be calculated quickly and accurately, which can provide a reference for the rapid assessment of personnel injuries and rescue and protection.

[0055] In a possible implementation manner, S303 specifically includes:

[0056] S3031: Calculate the total energy flux density generated by the explosion:

[0057]

[0058] Among them, E s represents the total energy flux density, W represents the TNT equivalent of the charge, R represents the distance between the explosion point and the center of the frame, θ 1 ,θ 2 Represents the energy flux density coefficient.

[0059] In the present invention, the total energy flux density is calculated by the above method, which can more accurately consider the propagation and attenuation of explosion energy in space, thereby improving the accuracy and practicality of the evaluation. This helps engineers to more accurately evaluate the damage of the frame under the action of underwater explosion, and provides stronger support for the repair and improvement of the structure.

[0060] S3032: The plate racks are classified into primary plate racks, secondary plate racks and tertiary plate racks. The primary plate rack is the smallest unit. The secondary plate rack includes multiple primary plate racks, bottom longitudinal quilts and solid ribs. The tertiary plate rack includes multiple secondary plate racks, longitudinal quilts and ribs.

[0061] In the present invention, panels at different levels may have structural differences. By calculating the energy flux density they bear respectively, the damage to the overall structure can be more accurately evaluated. By calculating the energy flux density of panels at different levels, the stress conditions of panels at each level under the action of the explosion can be understood more specifically. The above method can more comprehensively and accurately evaluate the damage of panels at different levels under the action of underwater explosions, providing an important basis for structural optimization and reinforcement. It also helps engineers to more effectively deal with the impact of underwater explosions on the hull structure.

[0062] S3033: According to the equivalent stiffness of the plates at each level, the total energy flux density is distributed and the energy flux density of the underwater non-contact explosion borne by the plates is calculated:

[0063]

[0064] Among them, E I It represents the energy flux density of the first-level underwater non-contact explosion, E II represents the secondary underwater non-contact explosion energy flux density, E III It represents the energy flux density of the third-level underwater non-contact explosion, E s Represents the total energy flux density, K I Indicates the equivalent stiffness of the primary frame, K II represents the equivalent stiffness of the secondary frame, K III Represents the equivalent stiffness of the three-level plate frame.

[0065] S3034: Based on the equivalent plate thickness of the plate frame and the underwater non-contact explosion energy flux density borne by the plate frame, calculate the maximum deformation of the hull under the underwater explosion, and quantify the initial damage degree through the maximum deformation:

[0066]

[0067] Among them, w 0 represents the maximum deformation, s, q and g are intermediate parameters.

[0068]

[0069]

[0070] Where a represents half of the width of the plate rack, b represents half of the length of the plate rack, h represents the equivalent plate thickness of the plate rack, and E xIt represents the underwater non-contact explosion energy flux density borne by the plate frame, E x Including E I 、E II and E III , E I It represents the energy flux density of the first-level underwater non-contact explosion, E II represents the secondary underwater non-contact explosion energy flux density, E III represents the energy flux density of the third-level underwater non-contact explosion, σ ds Represents the dynamic yield limit of hull material.

[0071] In the present invention, this method of calculating the maximum deformation can comprehensively consider the structural characteristics of the plate frame and the influence of the explosion. The calculated maximum deformation can reflect the deformation of the plate frame under the action of underwater non-contact explosion, and can quickly and accurately calculate the initial damage degree of the hull structure under the action of underwater explosion, which can provide a reference for the rapid assessment of personnel injuries and rescue and protection.

[0072] Among them, the dynamic yield limit of the hull material σ ds Specifically:

[0073]

[0074] Among them, σ s represents the static yield limit of the hull material, represents the strain rate.

[0075] S4: The hull area with the initial damage degree greater than the preset damage degree is determined as the key local area.

[0076] It should be noted that when the initial damage degree is quantified by the length of the damaged major axis, the preset damage degree may be the preset damage major axis length. When the initial damage degree is quantified by the maximum deformation, the preset damage degree may be the preset deformation.

[0077] Among them, those skilled in the art can set the preset damage degree and the preset deformation amount according to actual conditions, and the present invention does not limit this.

[0078] S5: Based on the operating parameters and the structural data of the key local areas, the precise degree of damage to the key local areas of the hull under the action of underwater explosion is calculated based on the finite element analysis method.

[0079] In a possible implementation, S5 specifically includes:

[0080] S501: Constructing an explosion shock wave model according to operating parameters.

[0081] Optionally, S501 specifically includes:

[0082] S5011: Determine the volume acceleration of the explosion shock wave according to the working condition parameters:

[0083]

[0084] in, represents the volume acceleration of the explosion shock wave, t represents time, a c represents the radius of the explosive, ρ f Represents the density of water, P c represents the peak pressure generated by the explosion, e represents a natural constant, T c represents the characteristic time constant.

[0085] The peak pressure generated by the explosion is P c Specifically:

[0086] P c =52.12(m c / a c ) 1.18

[0087] Among them, m c Indicates the mass of explosive.

[0088] Characteristic time constant T c Specifically:

[0089] T c =0.0895m c (a c / m c ) 0.185 .

[0090] It should be noted that by accurately calculating the volume acceleration, peak pressure and characteristic time constant of the explosion shock wave, the propagation characteristics of the explosion shock wave in water can be accurately simulated. This precise simulation helps to more accurately predict the force of the explosion shock wave on the hull, thereby improving the reliability and accuracy of the analysis results.

[0091] S5012: Determine the volume velocity and volume displacement of the explosion shock wave according to the volume acceleration of the explosion shock wave:

[0092]

[0093] in, represents the volume velocity of the explosion shock wave, and V represents the volume displacement of the explosion shock wave.

[0094] It should be noted that by determining the volume velocity and volume displacement of the explosion shock wave, the dynamic characteristics of the volume change during the explosion process can be captured, and the velocity and displacement information at different time points during the propagation of the explosion wave can be provided.

[0095] S5013: Determine the radial displacement and velocity of the bubbles in the shock wave based on the volume displacement of the explosion shock wave:

[0096] a(t)=[3V(t) / 4π] 1 / 3

[0097]

[0098] Where a represents the radial displacement of the bubble, represents the bubble radial velocity.

[0099] In the present invention, by determining the radial displacement and velocity of the bubbles in the shock wave, the behavior of the bubbles generated by the explosion in water can be simulated, especially the expansion and contraction process of the bubbles, which is an important aspect of understanding the impact of the explosion shock wave on the surrounding environment.

[0100] Furthermore, by constructing a detailed explosion shock wave model and determining key parameters, the accuracy and efficiency of underwater explosion analysis can be significantly improved. This approach helps to better understand the impact of explosions on ship structures, thus providing a solid foundation for design optimization and safety assessment.

[0101] S502: Determine the dynamic stress-strain relationship.

[0102] Optionally, S502 specifically includes: determining a dynamic stress-strain relationship according to the following formula:

[0103]

[0104] in, represents the strain rate, D represents the dynamic response constant of the hull material, σ' 0 represents the dynamic yield stress, σ 0 represents the static yield stress, and r represents the strain sensitivity constant of the hull material.

[0105] In the present invention, by determining the dynamic stress-strain relationship, the mechanical behavior of the material under high strain rate conditions can be accurately simulated. This method helps to improve the accuracy of finite element analysis, support structural damage assessment, optimize material selection and structural design, and thus enhance the safety and reliability of the structure under extreme conditions such as explosion impact.

[0106] S503: Determine the evolution mode of structural damage.

[0107] Optionally, S503 specifically includes: determining a structural damage evolution mode according to the following formula.

[0108]

[0109] Among them, G f represents the fracture energy density, represents plastic deformation, represents the initial plastic deformation, represents the final plastic deformation, L represents the characteristic length, σ y It represents the stress sustained during plastic deformation, and d represents the differential sign.

[0110] Among them, the fracture energy density refers to the energy absorbed per unit area of ​​the material during the fracture process.

[0111] In the present invention, by determining the evolution mode of structural damage, the fracture characteristics of the material can be quantitatively evaluated, the damage accumulation process can be captured, a basis for structural design can be provided, the accuracy of finite element analysis can be improved, and the structural performance under different load conditions can be evaluated. This method can help designers and engineers better understand and predict the response and damage of the structure under complex load conditions, thereby improving the safety and reliability of the structure.

[0112] S504: Using acoustic-structural coupling and finite element analysis, the precise extent of damage to key local areas of the hull under the action of underwater explosions is calculated.

[0113] In the present invention, the effect of underwater explosion on the hull can be simulated more accurately through the acoustic-structural coupling method. The interaction between fluid and structure is taken into account, and the propagation of shock waves in water and their interaction with the hull can be described more accurately, thereby improving the accuracy of the calculation.

[0114] Optionally, S504 specifically includes:

[0115] S5041: Using acoustic-structure coupling, assuming that the fluid is linear and weakly compressible, and that the pressure depends only on the density, determine the pressure equation:

[0116]

[0117] Where p represents the flow field pressure, f represents the pressure function, and ρ f represents the density of water, ρ 0 represents the average density of water, Represents the symbol of partial derivative.

[0118] It is important to note that by assuming that the fluid is linear, the coupling equations between acoustics and structure can be simplified. This makes the problem easier to solve, as linear equations are generally simpler and faster to compute than nonlinear equations. In most underwater explosion situations, the propagation of sound waves in water can be approximated as linear, especially far away from the explosion source. This makes the model simpler without significantly sacrificing accuracy.

[0119] S5042: Simulate the flow in acoustic mode and determine the continuity equation:

[0120]

[0121] Where t represents time, v represents flow velocity, Represents the Hamilton operator.

[0122] It should be noted that the continuity equation describes the continuity of the fluid medium and ensures the conservation of mass in the simulation.

[0123] S5043: Substitute the pressure equation into the continuity equation:

[0124]

[0125] make Then we have:

[0126]

[0127] S5044: Determine the momentum conservation equation for an inviscid fluid:

[0128]

[0129] It should be noted that the momentum conservation equation accurately describes the momentum change in the fluid medium and ensures the conservation of momentum.

[0130] S5045: Discretize both sides of the momentum conservation equation:

[0131]

[0132] Substitution Then we have:

[0133]

[0134] S5046: Integrate in the flow field to obtain the dynamic equation of the fluid medium:

[0135]

[0136] Among them, V f represents the flow field, V represents the fluid volume, d represents the differential sign, and δp represents the pressure change.

[0137] S5047: Set the boundary tension of each hull surface and introduce Green's formula into the dynamic equation of the fluid medium:

[0138]

[0139] Among them, S represents the boundary surface, S fp represents the free surface boundary surface, and T(x) represents the boundary tension on the hull surface.

[0140] Among them, Green's formula converts volume integrals into surface integrals, so that the mechanical behavior on the boundary can be described more accurately. This can more accurately capture the interaction of explosion waves on the fluid and structure boundaries. Through Green's formula, complex volume mechanics problems can be simplified, making calculations more intuitive and easy to implement.

[0141] It should be noted that by setting boundary conditions, the boundary effects in actual situations can be accurately simulated to improve the realism of the simulation.

[0142] S5048: Based on the dynamic equation of the fluid medium, finite element analysis is used to simulate and calculate the energy density of key local areas of the hull under the action of underwater explosion.

[0143] Specifically, establish a geometric model of the hull, especially a detailed model of the key local areas. Establish a geometric model of the waters around the explosion to cover the impact range of the explosion. Define the mechanical performance parameters of the hull material, including density, elastic modulus, Poisson's ratio, yield stress, etc. Define the physical properties of water, such as density and sound speed. Mesh the hull structure, and use fine meshes in key local areas to improve calculation accuracy. Mesh the fluid domain to ensure that it matches the structural mesh. Set appropriate boundary conditions at the boundaries of the fluid domain, such as free surfaces, non-reflecting boundaries, etc. Set the boundary conditions of the hull structure to ensure that they are consistent with the actual working conditions. Afterwards, solve the coupling equations through an iterative method to obtain the pressure, velocity, stress and strain distribution at each time step. Calculate the strain energy density per unit volume:

[0144] G=∫σ(ε)dε

[0145] Among them, G represents the energy density of the key local area under the action of underwater explosion, σ(ε) represents the stress-strain relationship function of the key local area under the action of underwater explosion, which is obtained through finite element analysis, ε represents strain, and d represents the differential sign.

[0146] In the present invention, by calculating the strain energy density in detail, the performance of materials under complex loading conditions can be better understood and predicted, providing reliable data support for engineering design and safety assessment.

[0147] S5049: Compare the energy density of the key local area under the action of underwater explosion with the fracture energy density of the hull to determine the precise degree of damage to the key local area of ​​the hull under the action of underwater explosion.

[0148] Optionally, the precise degree of damage is specifically:

[0149] τ=tanh(GG f )

[0150] Among them, τ represents the precise degree of damage, tanh represents the hyperbolic tangent function, G represents the energy density of the key local area under the action of underwater explosion, and G f represents the fracture energy density.

[0151] In the present invention, by comparing the energy density of the key local area under the action of underwater explosion with the fracture energy density of the hull, and using the hyperbolic tangent function to calculate the precise degree of damage, a damage assessment method with high sensitivity, strong real-time performance, wide applicability and easy quantification can be provided. This method can not only accurately capture the subtle changes in the degree of damage, but also provide an important reference for structural design optimization and maintenance, significantly improving the safety and reliability of the hull structure.

[0152] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include at least:

[0153] (1) In the present invention, based on the explosion mechanics theory and the typical structure of the hull, according to the working condition parameters, the equivalent plate thickness of the plate frame and the equivalent stiffness of the plate frame, the initial damage degree of the hull structure under the action of the underwater explosion is calculated quickly and accurately, which can provide a reference for the rapid assessment of personnel injuries and rescue and protection.

[0154] (2) In the present invention, the hull area with a preliminary damage degree greater than the preset damage degree is determined as the key local area, and then a detailed finite element analysis is performed on the key local area to improve the refinement and accuracy of the local structural damage assessment. There is no need to simulate the entire hull every time, which reduces the complexity and time consumption of the simulation, shortens the assessment time, and can meet the needs of rapid assessment.

[0155] Reference Manual Attached Figure 3 , showing a schematic structural diagram of a system for assessing local structural damage of an underwater explosion hull provided by the present invention.

[0156] The present invention further provides a system 20 for assessing damage to a local structure of a hull caused by an underwater explosion, which is applied to the above-mentioned method for assessing damage to a local structure of a hull caused by an underwater explosion, and comprises:

[0157] Processor 201.

[0158] The memory 202 stores computer-readable instructions. When the computer-readable instructions are executed by the processor 201, the method for assessing damage to a local structure of a ship hull caused by an underwater explosion as described in the method embodiment is implemented.

[0159] The underwater explosion hull local structure damage assessment system 20 provided by the present invention can execute the above-mentioned underwater explosion hull local structure damage assessment method and achieve the same or similar technical effects. To avoid repetition, the present invention will not go into details.

[0160] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include at least:

[0161] (1) In the present invention, based on the explosion mechanics theory and the typical structure of the hull, according to the working condition parameters, the equivalent plate thickness of the plate frame and the equivalent stiffness of the plate frame, the initial damage degree of the hull structure under the action of the underwater explosion is calculated quickly and accurately, which can provide a reference for the rapid assessment of personnel injuries and rescue and protection.

[0162] (2) In the present invention, the hull area with a preliminary damage degree greater than the preset damage degree is determined as the key local area, and then a detailed finite element analysis is performed on the key local area to improve the refinement and accuracy of the local structural damage assessment. There is no need to simulate the entire hull every time, which reduces the complexity and time consumption of the simulation, shortens the assessment time, and can meet the needs of rapid assessment.

[0163] It should be understood that the processor in the embodiment of the present invention may be a central processing unit (CPU), and the processor may also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0164] It should also be understood that the memory in the embodiments of the present invention may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0165] The above embodiments can be implemented in whole or in part by software, hardware (such as circuits), firmware or any other combination. When implemented by software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the process or function described in the embodiment of the present invention is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center by wired (such as infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that contains one or more available media sets. The available medium can be a magnetic medium (for example, a floppy disk, a hard disk, a tape), an optical medium (for example, a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state hard disk.

[0166] It should be understood that the term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship, but it may also indicate an "and / or" relationship. Please refer to the context for specific understanding.

[0167] In the present invention, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can be represented by: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0168] It should be understood that in various embodiments of the present invention, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0169] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0170] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described equipment, devices and units can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0171] In the several embodiments provided by the present invention, it should be understood that the disclosed devices, apparatuses and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0172] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0173] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0174] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0175] An embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein when the program is executed by a processor, the method for assessing damage to a local structure of a hull caused by an underwater explosion as described in the method embodiment is implemented.

[0176] A computer-readable storage medium provided by the present invention can implement the steps and effects of the method for assessing local structural damage of an underwater explosion hull of the above method embodiment. To avoid repetition, the present invention will not go into details.

[0177] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include at least:

[0178] (1) In the present invention, based on the explosion mechanics theory and the typical structure of the hull, according to the working condition parameters, the equivalent plate thickness of the plate frame and the equivalent stiffness of the plate frame, the initial damage degree of the hull structure under the action of the underwater explosion is calculated quickly and accurately, which can provide a reference for the rapid assessment of personnel injuries and rescue and protection.

[0179] (2) In the present invention, the hull area with a preliminary damage degree greater than the preset damage degree is determined as the key local area, and then a detailed finite element analysis is performed on the key local area to improve the refinement and accuracy of the local structural damage assessment. There is no need to simulate the entire hull every time, which reduces the complexity and time consumption of the simulation, shortens the assessment time, and can meet the needs of rapid assessment.

[0180] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

[0181] There are a few points to note:

[0182] (1) The drawings of the embodiments of the present invention only relate to the structures related to the embodiments of the present invention, and other structures may refer to the general design.

[0183] (2) For the sake of clarity, in the drawings used to describe the embodiments of the present invention, the thickness of the layers or regions is exaggerated or reduced, that is, these drawings are not drawn according to the actual scale. It is understood that when an element such as a layer, film, region or substrate is referred to as being "on" or "under" another element, the element may be "directly" "on" or "under" the other element or there may be intermediate elements.

[0184] (3) In the absence of conflict, the embodiments of the present invention and the features therein may be combined with each other to obtain new embodiments.

[0185] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. The protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for assessing damage to a local structure of a hull caused by an underwater explosion, characterized in that: include: S1: Acquire underwater explosion working condition parameters, wherein the working condition parameters include: TNT equivalent of charge and explosion position; S2: Acquire hull structure data; S3: Calculating the initial damage degree of the hull under the underwater explosion based on the working condition parameters and the hull structure data and based on the equivalent simulation method; S4: The hull area with the initial damage degree greater than the preset damage degree is determined as the key local area; S5: Calculate the precise degree of damage to the key local area of ​​the hull under the underwater explosion based on the working condition parameters and the structural data of the key local area and the finite element analysis method; Wherein, the S3 specifically includes: S301: Calculate the equivalent plate thickness of the plate rack according to the structural data of the plate rack; S302: Calculate the equivalent stiffness of the panel frame according to the structural data of the panel frame; S303: calculating the initial damage degree of the hull under the underwater explosion based on the equivalent simulation method according to the working condition parameters, the equivalent plate thickness of the plate frame and the equivalent stiffness of the plate frame; Wherein, the S303 is specifically: The damaged major axis length of the hull under the action of the underwater explosion is calculated according to the following formula, and the initial damage degree is quantified by the damaged major axis length: Among them, L p It represents the length of the damaged major axis, which is used to characterize the initial damage degree, W represents the TNT equivalent of the charge, h represents the equivalent plate thickness of the plate frame, and K represents the equivalent stiffness of the plate frame; The equivalent plate thickness of the plate frame is specifically: Wherein, h represents the equivalent plate thickness of the plate frame, I represents the section inertia moment of the reinforcement structure, i represents the number of reinforcement structures in the x direction, j represents the number of reinforcement structures in the y direction, x and y represent the rotation axis directions of the reinforcement structures, a represents half of the width of the plate frame, and b represents half of the length of the plate frame; The equivalent stiffness of the plate frame is specifically: Wherein, K represents the equivalent stiffness of the plate frame, E represents the elastic modulus of the hull material, μ represents the Poisson's ratio, a represents half of the width of the plate frame, and b represents half of the length of the plate frame.

2. The method for assessing damage to local structure of underwater explosion hull according to claim 1, characterized in that: The S5 specifically includes: S501: constructing an explosion shock wave model according to the operating condition parameters; S502: Determine the dynamic stress-strain relationship; S503: Determine the evolution mode of structural damage; S504: Using acoustic-structural coupling and finite element analysis, the precise extent of damage to key local areas of the hull under the action of underwater explosions is calculated.

3. The method for assessing damage to local structure of underwater explosion hull according to claim 2, characterized in that: The S501 specifically includes: S5011: Determine the volume acceleration of the explosion shock wave according to the working condition parameters: in, represents the volume acceleration of the explosion shock wave, t represents time, a c represents the radius of the explosive, ρ f Represents the density of water, P c represents the peak pressure generated by the explosion, e represents a natural constant, T c represents the characteristic time constant; The peak pressure P generated by the explosion c Specifically: P c =52.12(m c / a c ) 1.18 Among them, m c Indicates the mass of explosives; The characteristic time constant T c Specifically: T c =0.0895m c (a c / m c ) 0.185 ; S5012: Determine the volume velocity and volume displacement of the explosion shock wave according to the volume acceleration of the explosion shock wave: in, represents the volume velocity of the explosion shock wave, V represents the volume displacement of the explosion shock wave; S5013: Determine the radial displacement and velocity of the bubbles in the shock wave based on the volume displacement of the explosion shock wave: a(t)=[3V(t) / 4π] 1 / 3 Where a represents the radial displacement of the bubble, represents the bubble radial velocity.

4. The method for assessing damage to local structure of underwater explosion hull according to claim 2, characterized in that: The S502 is specifically as follows: The dynamic stress-strain relationship is determined according to the following formula: in, represents the strain rate, D represents the dynamic response constant of the hull material, σ'0 represents the dynamic yield stress, σ0 represents the static yield stress, and r represents the strain sensitivity constant of the hull material.

5. The method for evaluating damage to local structure of underwater explosion hull according to claim 2, characterized in that: The S503 is specifically as follows: According to the following formula, the evolution mode of structural damage is determined; Among them, G f represents the fracture energy density, represents plastic deformation, represents the initial plastic deformation, represents the final plastic deformation, L represents the characteristic length, σ y It represents the stress sustained during plastic deformation, and d represents the differential sign.

6. The method for evaluating damage to local structure of underwater explosion hull according to claim 2, characterized in that: The S504 specifically includes: S5041: Using acoustic-structure coupling, assuming that the fluid is linear and weakly compressible, and that the pressure depends only on the density, determine the pressure equation: Where p represents the flow field pressure, f represents the pressure function, and ρ f represents the density of water, ρ0 represents the average density of water, represents the symbol of partial derivative; S5042: Simulate the flow in acoustic mode and determine the continuity equation: Where t represents time, v represents flow velocity, represents the Hamilton operator; S5043: Substitute the pressure equation into the continuity equation: make Then we have: S5044: Determine the momentum conservation equation for an inviscid fluid: S5045: Discretize both sides of the momentum conservation equation: Substitution Then we have: S5046: Integrate in the flow field to obtain the dynamic equation of the fluid medium: Among them, V f represents the flow field, V represents the fluid volume, d represents the differential sign, and δp represents the pressure change; S5047: Set the boundary tension of each hull surface and introduce Green's formula into the dynamic equation of the fluid medium: Among them, S represents the boundary surface, S fp represents the free surface boundary surface, T(x) represents the boundary tension on the hull surface; S5048: Based on the dynamic equation of the fluid medium, finite element analysis is used to simulate and calculate the energy density of the key local area of ​​the hull under the action of underwater explosion; S5049: Compare the energy density of the key local area under the action of underwater explosion with the fracture energy density of the hull to determine the precise degree of damage to the key local area of ​​the hull under the action of underwater explosion.

7. The method for evaluating damage to local structure of underwater explosion hull according to claim 6, characterized in that: The precise degree of damage is specifically: τ=tanh(GG f ) Among them, τ represents the precise degree of damage, tanh represents the hyperbolic tangent function, G represents the energy density of the key local area under the action of underwater explosion, and G f represents the fracture energy density.

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