A corrosion simulation analysis method for aircraft aluminum alloy connection structures

Abstract

The present application belongs to the technical field of corrosion analysis of aircraft aluminum alloy connection structures, and specifically relates to a corrosion simulation analysis method for aircraft aluminum alloy connection structures, comprising: step 1, establishing a simulation model for the self-corrosion problem of aircraft aluminum alloy metal materials; step 2, using the simulation model for the self-corrosion problem of aircraft aluminum alloy metal materials, performing multi-working condition simulation, analyzing the simulation results, and correcting the simulation model; step 3, based on the simulation model for the self-corrosion problem of aircraft aluminum alloy metal materials, establishing a corrosion simulation model for aircraft aluminum alloy connection structures; step 4, using the corrosion simulation model for aircraft aluminum alloy connection structures, performing multi-working condition corrosion simulation analysis on aircraft aluminum alloy connection structures.

Description

Technical Field

[0001] The present application belongs to the technical field of corrosion analysis of aircraft aluminum alloy connection structures, and specifically relates to a corrosion simulation analysis method for aircraft aluminum alloy connection structures. Background Art

[0002] The aviation industry generally adds elements to aluminum smelting and processing it into aluminum alloys to improve the structural strength of aircraft. This will produce a non-uniform microstructure and induce localized corrosion, especially pitting corrosion.

[0003] For many years, the understanding and prediction of the initiation and development of pitting corrosion in aluminum alloys has been a hot topic and difficulty in research. The corrosion rate obtained solely from Faraday's law is not comprehensive enough and may even be inaccurate for aluminum alloy materials on aircraft.

[0004] Laboratory accelerated corrosion tests are conducted on key corrosion parts of aircraft, such as tensile plates of typical connection structures. Laboratory acceleration spectra obtained by engineering equivalent are usually used and carried out in a cyclic immersion manner. By comparing and analyzing the data with real long-term natural environment exposure tests, the accuracy of the laboratory acceleration spectra is verified and the corrosion resistance of the aircraft aluminum alloy connection structure is obtained.

[0005] However, the typical environmental conditions of actual aircraft service are complex and changeable, with many critical corrosion areas. The time period for determining and verifying the engineering equivalence relationship of laboratory accelerated spectrum tests is long, the cost is high, and the economic efficiency is poor.

[0006] This application is proposed in view of the above-mentioned technical defects. Summary of the Invention

[0007] The purpose of this application is to provide a corrosion simulation analysis method for aircraft aluminum alloy connection structures to overcome or alleviate at least one of the known technical defects.

[0008] The technical solution of this application is:

[0009] A corrosion simulation analysis method for aircraft aluminum alloy connection structures, comprising:

[0010] Step 1: Establish a simulation model for the self-corrosion problem of aircraft aluminum alloy metal materials;

[0011] Step 2: Using a simulation model of the self-corrosion problem of aircraft aluminum alloy metal materials, conduct multi-condition simulations, analyze the simulation results, and modify the simulation model;

[0012] Step 3: Based on the simulation model of the self-corrosion problem of aircraft aluminum alloy metal materials, a corrosion simulation model of aircraft aluminum alloy connection structure is established;

[0013] Step 4: Using the aircraft aluminum alloy connection structure corrosion simulation model, perform multi-condition corrosion simulation analysis on the aircraft aluminum alloy connection structure.

[0014] Optionally, in the above-mentioned aircraft aluminum alloy connection structure corrosion simulation analysis method, in step 1, a simulation model for the self-corrosion problem of aircraft aluminum alloy metal materials is established, and basic assumptions are established:

[0015] The oxygen reduction reaction occurs only on the surface of the second phase, and the active dissolution of the metal occurs only on the matrix;

[0016] The electrolyte is an infinitely dilute solution;

[0017] The passivation film does not dissolve, and Cl is not considered - Destructive effect on the passivation film;

[0018] Without considering the influence of the double layer on the electrode surface, all the physical and chemical processes considered include electrode reaction, material transport and homogeneous reaction in the electrolyte, and deposition of surface corrosion products.

[0019] Ignoring the adsorption and desorption process of ions at the interface, the interfacial ion concentration distribution is completely controlled by diffusion and electromigration;

[0020] The electrolyte mass transfer only considers diffusion and electromigration, and does not consider convection;

[0021] Only the microscopic galvanic corrosion under open circuit conditions is considered, without external voltage application, and the electrode reaction is driven by the galvanic effect between IMPs and the substrate;

[0022] Consider the changes in the electrode surface over time due to active dissolution and the impact of these changes on corrosion expansion;

[0023] Considering the passivation effect of corrosion product deposition on the active reaction surface and its influence on the subsequent corrosion process, once Al(OH)3 is deposited, it will no longer dissolve.

[0024] Optionally, in the above-mentioned aircraft aluminum alloy connection structure corrosion simulation analysis method, in step 1, in establishing a simulation model for the self-corrosion problem of aircraft aluminum alloy metal materials, it is assumed that the thickness of the diffusion layer is 10 μm;

[0025] The initial values of the ion concentrations on the upper surface of the electrolyte domain are consistent with the ion concentrations of the electrolyte solution;

[0026] The boundaries on both sides of the electrolyte domain are insulating boundaries, and the lower surface serves as the electrode surface.

[0027] Optionally, in the above-mentioned aircraft aluminum alloy connection structure corrosion simulation analysis method, in step 2, the simulation results are analyzed, including analysis of the simulation results of Al3Fe single-phase inclusions, MgZn2 single-phase inclusions, multi-phase inclusions, and aluminum alloy self-corrosion.

[0028] Optionally, in the above-mentioned aircraft aluminum alloy connection structure corrosion simulation analysis method, step three is specifically as follows:

[0029] Based on the simulation model of the self-corrosion problem of aircraft aluminum alloy metal materials, a specimen-level galvanic corrosion simulation model of aircraft aluminum alloy connection structures was established. Simulation calculations were performed to obtain the coupling potential and galvanic current. The results were compared and analyzed with the test results, and then the specimen-level galvanic corrosion simulation model of aircraft aluminum alloy connection structures was revised.

[0030] Based on the specimen-level galvanic corrosion simulation model of aircraft aluminum alloy connection structures, a component-level galvanic corrosion simulation model of aircraft aluminum alloy connection structures was established. Simulation calculations were performed to obtain the potential distribution, corrosion morphology, and microstructure morphology. The results were compared and analyzed with the experimental results, and then the component-level galvanic corrosion simulation model of aircraft aluminum alloy connection structures was modified to obtain the corrosion simulation model of aircraft aluminum alloy connection structures.

[0031] This application has at least the following beneficial technical effects:

[0032] Provided is a corrosion simulation analysis method for aircraft aluminum alloy connection structures. A simulation method is used to conduct multi-condition corrosion simulation analysis of aircraft aluminum alloy connection structures using a corrosion simulation model of the aircraft aluminum alloy connection structure. The method can quickly predict the potential distribution, corrosion rate, corrosion deformation, and mass loss rate of the aircraft aluminum alloy connection structure, and locate dangerous locations of the structure. The method is low in cost and can effectively guide the design and improvement of aircraft aluminum alloy connection structures, as well as the maintenance of aircraft aluminum alloy connection structures in practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of a corrosion simulation analysis method for aircraft aluminum alloy connection structures provided in an embodiment of the present application;

[0034] Figure 2 This is a schematic diagram of a geometric model of micro-galvanic corrosion of aircraft aluminum alloy metal materials provided in an embodiment of the present application;

[0035] Figure 3 This is a schematic diagram of a geometric model for constructing the normal direction of an aluminum alloy interface by introducing a level set function, as provided in an embodiment of the present application;

[0036] Figure 4 yes Figure 3 A partial enlarged view of;

[0037] Figure 5 yes Figure 3 B is a partial enlarged view;

[0038] Figure 6 yes Figure 3 A partial enlarged view of C.

[0039] In order to better illustrate this embodiment, some contents of the drawings may be omitted, enlarged or reduced, which is only used for illustrative purposes and should not be construed as limiting the present application. DETAILED DESCRIPTION

[0040] To make the technical solution and its advantages of this application more clear, the technical solution of this application will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described here are only some of the embodiments of this application and are only used to explain this application, not to limit this application. It should be noted that for ease of description, only the parts relevant to this application are shown in the accompanying drawings, and other relevant parts can refer to the general design.

[0041] In addition, unless otherwise defined, the technical or scientific terms used in the description of this application shall have the ordinary meanings understood by those skilled in the art to which this application belongs. The term "include" as used in the description of this application means that the concepts preceding the term include the concepts listed after the term and their equivalents, without excluding other related concepts.

[0042] In addition, the words used in the description of this application to indicate orientation are only used to indicate relative directions or positional relationships. When the absolute position of the object being described changes, its relative positional relationship may also change accordingly. It should also be noted that, unless otherwise clearly specified and limited, the words "installation", "connection" and similar words used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand their specific meanings in this application based on the specific circumstances.

[0043] With the development and improvement of computer technology and corrosion electrochemical theory, corrosion simulation technology can accurately predict the corrosion degree of aircraft structures under different operating conditions in a relatively short time. Therefore, corrosion simulation analysis methods can be used to analyze the corrosion resistance of aircraft aluminum alloy connection structures.

[0044] However, corrosion simulation analysis is still in its infancy and lacks effective tools and methods. Adaptive design for aircraft corrosive environments relies primarily on the designer's experience and physical verification during the R&D phase. However, simulation analysis cycles are long and costly. Furthermore, existing methods for calculating the self-corrosion of metal materials are only applicable to pure metals and are incomplete or even inaccurate for the aluminum alloys used on aircraft.

[0045] Based on the above, this application provides a corrosion simulation analysis method for aircraft aluminum alloy connection structures based on the numerical simulation theory of the damage dynamics equation, and conducts comparative analysis on mainstream simulation tools, such as Figure 1 shown.

[0046] Step 1: Establish a simulation model for the self-corrosion problem of aircraft aluminum alloy metal materials.

[0047] For aluminum alloys, their self-corrosion behavior often presents localized corrosion in the early stages, such as pitting. The corrosion rate obtained by Faraday's law is only applicable to pure metals and is incomplete or even inaccurate for aluminum alloy materials. The present invention addresses the self-corrosion problem of aircraft aluminum alloy metal materials from the perspective of the material's microstructure and comprehensively considers the influence of the second phase structure to establish the basic assumptions of the simulation model as follows:

[0048] The oxygen reduction reaction occurs only on the surface of the second phase, and the active dissolution of the metal occurs only on the matrix;

[0049] The electrolyte is an infinitely dilute solution, that is, the activity a of substance i in the solution i Its concentration c can be used directly i to make a substitution;

[0050] The passivation film does not dissolve, and Cl is not considered - Destructive effect on the passivation film;

[0051] Without considering the influence of the double layer on the electrode surface, all the physical and chemical processes considered include electrode reaction, material transport (diffusion and migration) in the electrolyte and homogeneous reaction (Al 3+ Hydrolysis and Cl - composite reaction between them) and the deposition of surface corrosion products;

[0052] Ignore the adsorption and desorption process of ions at the interface and assume that the interface ion concentration distribution is completely controlled by diffusion and electromigration;

[0053] The electrolyte mass transfer only considers diffusion and electromigration, and does not consider convection;

[0054] Only the microscopic galvanic corrosion under open circuit conditions is considered, without external voltage application, and the electrode reaction is driven by the galvanic effect between IMPs and the substrate;

[0055] Consider the changes in the electrode surface over time due to active dissolution and the impact of these changes on corrosion expansion;

[0056] Considering the passivation effect of corrosion product deposition on the active reaction surface and its influence on the subsequent corrosion process, once Al(OH)3 is deposited, it will no longer dissolve.

[0057] Based on the basic assumptions of the simulation model, the expansion of aluminum alloy along the depth direction under the combined action of Al3Fe and MgZn2 in the inclusion phase is considered, and a mathematical characterization of the electrode reaction, homogeneous reaction and steric effect of corrosion products in microgalvanic corrosion is established.

[0058] Microgalvanic corrosion geometric model Figure 2 As shown, the electrolyte is a 0.1 mol / L NaCl neutral solution.

[0059] For the electrode reaction, it is assumed that the Al substrate covered by the passivation film is inactive, that is, neither active dissolution occurs nor oxygen reduction reaction is supported. In a neutral solution, oxygen reduction and active dissolution of aluminum proceed through the following electrode reactions:

[0060] Anode: Al-3e - →Al 3+ ;

[0061] Cathode: O2+2H2O+4e - →4OH - .

[0062] For homogeneous reactions, the Nernst-Planck equation, which represents the conservation of species within the entire electrolyte domain, is used as the governing equation:

[0063]

[0064] Among them, c i is the concentration of the i-th ion; t is time; D i is the diffusion coefficient of the i-th ion; z i is the charge number of the i-th ion; R is the gas constant; T is the absolute temperature; F is the Faraday constant; is the potential gradient; is the stoichiometric coefficient of the i-th ion in the j-th reaction; is the forward reaction rate constant of the jth reaction, x and y are the position coordinates; is the reverse reaction rate constant of the jth reaction; N r is the number of homogeneous reactions; m is the number of forward reaction ions; n is the number of reverse reaction ions.

[0065] For the steric effect of corrosion products, it is assumed that when the concentration of Al(OH)3 is greater than its solubility of 1.86×10 -6 mol / m 3 When the concentration of Al(OH)3 is 100 times that of Al(OH)3, it reaches a supersaturated state and Al(OH)3 will crystallize out. The precipitation process of Al(OH)3 is fast enough, and the deposition rate of Al(OH)3 is equal to the formation rate of Al(OH)3, so that the concentration of Al(OH)3 will not increase any further. The specific expression is as follows:

[0066]

[0067] Among them, r deposition is the deposition rate of Al(OH)3; r formation is the formation rate of Al(OH)3; is the concentration of Al(OH)3; is the solubility of Al(OH)3.

[0068] To quantitatively describe the steric effect, the coverage of the deposition product is introduced to quantitatively describe the coverage of the electrode surface by Al(OH)3 precipitation. Assuming that Al(OH)3 deposition occurs only at the boundary, the boundary coverage is considered to be a boundary with no thickness. Its change over time is determined by the deposition rate. Therefore, the ordinary differential equation (ODE) is introduced as follows:

[0069]

[0070]

[0071] Where θ is the coverage of Al(OH)3 at the boundary; t is the time; δ is the thickness of Al(OH)3 deposition that can completely cover the active electrode surface; is the molar mass of Al(OH)3; is the density of Al(OH)3; V mesh / S mesh The volume of sedimentation products generated in each unit grid can be converted into the thickness of the sediment layer, that is, the grid size.

[0072] In order to characterize the influence of the steric effect of corrosion products on corrosion, the if condition function is introduced for correction when calculating the cathode and anode reaction rates on the electrode surface, as follows:

[0073]

[0074] Based on existing research, considering the effect of multiphase coupling and the inactive state of the passivation film, a pre-processed geometric model of the normal direction of the aluminum alloy interface can be constructed. After verification, the initial values such as the diffusion layer thickness and mixing potential that are most suitable for the self-corrosion problem of aircraft alloy metal materials can be determined.

[0075] The level set structure function is introduced, and the effect of multiphase coupling and the inactive state of the passivation film are considered at the same time, including four states: Al3Fe, MgZn2, Al matrix and passivation film. In order to distinguish the influence of four different phases on the same interface, four constants of -1, 0, 1 and 2 are used to represent the position of each phase in the model, as follows:

[0076]

[0077] In order to deal with the sudden changes in values at the phase boundaries caused by the constant values between phases, the Heaviside function H(ξ) is introduced to judge the boundaries of each phase. The Heaviside function H(ξ) is further processed and second-order smoothing is performed within the range of 0±0.05μm.

[0078]

[0079] Where ξ is the variable of the Heaviside function. Introducing the level set function The geometric model of the normal direction of the aluminum alloy interface is constructed, such as Figure 3-Figure 6 shown.

[0080]

[0081] Where H is the Heaviside function operation; x and y are position coordinates. (Geometric coordinate values can be deleted)

[0082] In order to characterize the influence of each phase on corrosion, the if condition function is introduced for correction when calculating the cathode and anode reaction rates on the electrode surface, as follows:

[0083]

[0084] It has been verified that the thickness of the electrolyte domain from 10μm to 200μm has little effect on the concentration calculation results. Therefore, it can be assumed that the thickness of the diffusion layer, that is, the electrolyte domain, is 10μm, which can not only ensure that the concentration gradient is sufficient to form in the domain, but also reduce the amount of calculation.

[0085] The initial values of the ion concentrations on the upper surface of the electrolyte domain are consistent with the ion concentrations of the electrolyte solution, that is, 0.1 mol / L NaCl solution, and the dissolved oxygen concentration is 0.258 mol / m3.

[0086] The boundaries on both sides of the electrolyte domain are insulating boundaries, and the lower surface serves as the electrode surface.

[0087] For mixed potential, it has been verified that appropriately increasing the smoothing interval of the Heaviside function H(ξ) can effectively improve the convergence. The mixed potential can be directly calculated according to the mixed potential theory without the need to set the corresponding initial value.

[0088] Step 2: Use the simulation model of the self-corrosion problem of aircraft aluminum alloy metal materials to perform multi-working condition simulation, analyze the simulation results, and modify the simulation model.

[0089] Specifically, it includes analysis of the simulation results of Al3Fe single-phase inclusions, MgZn2 single-phase inclusions, multi-phase inclusions, and aluminum alloy self-corrosion.

[0090] Step 3: Based on the simulation model of the self-corrosion problem of aircraft aluminum alloy metal materials, a corrosion simulation model of aircraft aluminum alloy connection structure is established.

[0091] Based on the simulation model of the self-corrosion problem of aircraft aluminum alloy metal materials, a galvanic corrosion simulation model of aircraft aluminum alloy connection structure specimen level was established. Simulation calculations were performed to obtain the coupling potential and galvanic current, which were compared and analyzed with the test results. The galvanic corrosion simulation model of aircraft aluminum alloy connection structure specimen level was then modified to ensure the reliability of the model.

[0092] Based on the specimen-level galvanic corrosion simulation model of aircraft aluminum alloy connection structure, a component-level galvanic corrosion simulation model of aircraft aluminum alloy connection structure was established. Simulation calculations were performed to obtain the potential distribution, corrosion morphology, and microstructure morphology. The results were compared and analyzed with the experimental results, and then the component-level galvanic corrosion simulation model of aircraft aluminum alloy connection structure was corrected to obtain the aircraft aluminum alloy connection structure corrosion simulation model to ensure the accuracy of the model.

[0093] Step 4: Using the aircraft aluminum alloy connection structure corrosion simulation model, perform multi-condition corrosion simulation analysis on the aircraft aluminum alloy connection structure.

[0094] Corrosion simulation analysis can be performed under four working conditions, including circumferential immersion test of typical dissimilar metal connectors of unpainted wing frames, circumferential immersion test of typical dissimilar metal connectors of painted wing frames, circumferential immersion test of typical metal and composite connectors of unpainted wing frames, and circumferential immersion test of typical metal and composite connectors of painted wing frames. The potential distribution, corrosion rate, corrosion deformation and mass loss rate of aircraft aluminum alloy connection structures can be predicted to identify dangerous locations of the structure.

[0095] When conducting multi-condition corrosion simulation analysis on aircraft aluminum alloy connection structures, the protection system can be considered at the same time.

[0096] The aircraft aluminum alloy connection structure corrosion simulation analysis method disclosed in the above embodiment adopts simulation means and uses an aircraft aluminum alloy connection structure corrosion simulation model to perform multi-working condition corrosion simulation analysis on the aircraft aluminum alloy connection structure. It can quickly predict the potential distribution, corrosion rate, corrosion deformation and mass loss rate of the aircraft aluminum alloy connection structure, find the dangerous positions of the structure, and has low cost. It can effectively guide the design and improvement of the aircraft aluminum alloy connection structure, as well as guide the maintenance of the aircraft aluminum alloy connection structure in practice.

[0097] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or replacements to the relevant technical features, and the technical solutions after these changes or replacements will fall within the scope of protection of the present application.

Claims

1. A corrosion simulation analysis method for aircraft aluminum alloy connection structure, characterized in that: include: Step 1: Establish a simulation model for the self-corrosion problem of aircraft aluminum alloy metal materials; Step 2: Using a simulation model of the self-corrosion problem of aircraft aluminum alloy metal materials, conduct multi-condition simulations, analyze the simulation results, and modify the simulation model; Step 3: Based on the simulation model of the self-corrosion problem of aircraft aluminum alloy metal materials, a corrosion simulation model of aircraft aluminum alloy connection structure is established; Step 4: Using the aircraft aluminum alloy connection structure corrosion simulation model, perform multi-condition corrosion simulation analysis on the aircraft aluminum alloy connection structure; In step 1, a simulation model for the self-corrosion problem of aircraft aluminum alloy metal materials is established, and basic assumptions are established: The oxygen reduction reaction occurs only on the surface of the second phase, and the active dissolution of the metal occurs only on the matrix; The electrolyte is an infinitely dilute solution; The passivation film does not dissolve, and Cl is not considered - Destructive effect on the passivation film; Without considering the influence of the double layer on the electrode surface, all the physical and chemical processes considered include electrode reaction, material transport and homogeneous reaction in the electrolyte, and deposition of surface corrosion products. Ignoring the adsorption and desorption process of ions at the interface, the interfacial ion concentration distribution is completely controlled by diffusion and electromigration; The electrolyte mass transfer only considers diffusion and electromigration, and does not consider convection; Only the microscopic galvanic corrosion under open circuit conditions is considered, without external voltage application, and the electrode reaction is driven by the galvanic effect between IMPs and the substrate; Consider the changes in the electrode surface over time due to active dissolution and the impact of these changes on corrosion expansion; Considering the passivation effect of corrosion product deposition on the active reaction surface and its influence on the subsequent corrosion process, at the same time, once Al(OH)3 is deposited, it will no longer dissolve; In step 1, a simulation model for the self-corrosion problem of aircraft aluminum alloy metal materials is established, assuming that the thickness of the diffusion layer is 10μm; The initial values of the ion concentrations on the upper surface of the electrolyte domain are consistent with the ion concentrations of the electrolyte solution; The boundaries on both sides of the electrolyte domain are insulating boundaries, and the lower surface serves as the electrode surface; The coverage of the deposition product is introduced to quantitatively describe the coverage of the electrode surface by Al(OH)3 precipitation. Assuming that Al(OH)3 deposition occurs only at the boundary, the boundary coverage is regarded as a boundary with no thickness, and its change over time is determined by the deposition rate. By introducing the level set function and considering the effects of multiphase coupling and the inactive state of the passivation film, a geometric model of the normal direction of the aluminum alloy interface was constructed. After verification, the diffusion layer thickness and initial value of the mixed potential that are most suitable for the self-corrosion problem of aircraft alloy metal materials were determined. The Heaviside function H(ξ) is introduced to judge the boundaries of each phase, and the Heaviside function H(ξ) is further processed by performing second-order smoothing in the range of 0±0.05μm to deal with the numerical mutations at the phase intersection caused by the constant value between the phases.

2. The corrosion simulation analysis method for aircraft aluminum alloy connection structure according to claim 1 is characterized in that: In step 2, the simulation results are analyzed, including the analysis of the simulation results of Al3Fe single-phase inclusions, MgZn2 single-phase inclusions, multi-phase inclusions, and aluminum alloy self-corrosion.

3. The corrosion simulation analysis method for aircraft aluminum alloy connection structure according to claim 2, characterized in that: Step three is as follows: Based on the simulation model of the self-corrosion problem of aircraft aluminum alloy metal materials, a galvanic corrosion simulation model of aircraft aluminum alloy connection structure specimen level was established. Simulation calculations were performed to obtain the coupling potential and galvanic current. The results were compared and analyzed with the test results, and then the galvanic corrosion simulation model of aircraft aluminum alloy connection structure specimen level was revised. Based on the specimen-level galvanic corrosion simulation model of aircraft aluminum alloy connection structure, a component-level galvanic corrosion simulation model of aircraft aluminum alloy connection structure was established. Simulation calculations were performed to obtain the potential distribution, corrosion morphology, and microstructure morphology. The results were compared and analyzed with the experimental results, and then the component-level galvanic corrosion simulation model of aircraft aluminum alloy connection structure was modified to obtain the corrosion simulation model of aircraft aluminum alloy connection structure.

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