Vehicle body corrosion prediction method, vehicle body corrosion prediction system, and vehicle body corrosion prediction program

Abstract

To provide a car body corrosion prediction method capable of accurately predicting corrosion of a car body of a newly designed vehicle, car body corrosion prediction system and car body corrosion prediction program.SOLUTION: A car body corrosion prediction method includes the steps of: constructing a shape model of a car body representing a shape of the car body by two-dimensional mesh; constructing a shape model of a peripheral region representing the peripheral region surrounding the car body by three-dimensional mesh; associating data relating to factors causing corrosion of the car body with a plurality of polyhedral elements of the shape model of the peripheral region; calculating a degree of corrosion per unit time for every plate-like element from corrosion action conditions associated with the polyhedral elements and data relating to positions and inclination angles of the plate-like elements of the shape model of the car body; and calculating a degree of corrosion of the car body after the lapse of a prescribed period based on the calculated degree of corrosion per unit time.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a vehicle body corrosion prediction method, a vehicle body corrosion prediction system, and a vehicle body corrosion prediction program for predicting the degree of corrosion occurring in a vehicle body due to the use of a vehicle. [Background Art]

[0002] Vehicles such as automobiles, when used for many years in, for example, a high-temperature and high-humidity environment, develop rust on the vehicle body, resulting in corrosion. In order to improve the corrosion resistance of vehicle bodies, conventional methods have involved collecting used vehicles, disassembling the vehicle body, and inspecting corroded sites. However, this method has problems in that it requires significant cost and time for vehicle collection and disassembly.

[0003] In order to reduce the cost and time required for vehicle body analysis, methods for predicting vehicle body corrosion through computer-based simulation have been developed in recent years.

[0004] For example, Patent Document 1 describes a vehicle body corrosion prediction method using a neural network incorporated in a computer. The neural network is pre-trained using teacher data in which the input data includes the temperature of the environment where the automobile is used, the amount of water exposure, humidity, salt content, elapsed time, mileage, the position of a three-dimensional mesh space obtained by dividing the automobile and its surrounding space at predetermined intervals, and the vehicle body division corresponding to the mesh space position, and the output data is the corrosion amount. In the input data, the vehicle body is broadly divided into sections such as doors, floors, body sides, and hoods.

[0005] In this method, the temperature, water exposure, humidity, salt content, elapsed time, mileage, mesh spatial position, and vehicle body category corresponding to the spatial position of the vehicle are input to a trained neural network, and the results output by the trained neural network are displayed on a screen as a predicted value of the corrosion amount. In this way, a vehicle corrosion prediction method using a neural network can simulate the degree of corrosion of a vehicle body on a computer without recovering or disassembling the vehicle after use. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2002-257689 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, the method described in Patent Document 1 has a problem in that it cannot make highly accurate predictions in response to changes in the shape of the vehicle body. For example, when rainwater adheres to the vehicle body, if the surface of the vehicle body is close to a vertical plane, the rainwater flows down due to gravity and does not easily accumulate on the vehicle body. However, if it is close to a horizontal plane, rainwater tends to accumulate, which makes corrosion more likely.

[0008] In the method described in Patent Document 1, although the location of corrosion on the vehicle body can be identified based on its position in a three-dimensional mesh space, the surface shape of the vehicle body is not identified in this three-dimensional mesh space. Therefore, it is not possible to appropriately predict how changes in the shape of the vehicle body will affect the degree of corrosion progression. Consequently, there is a problem in that the prediction accuracy is low when predicting the degree of corrosion for vehicles for which there is no training data, such as newly designed vehicle bodies.

[0009] The present invention has been made in view of the above problems, and aims to provide a vehicle body corrosion prediction method, a vehicle body corrosion prediction system, and a vehicle body corrosion prediction program that can accurately predict vehicle body corrosion for newly designed vehicles. [Means for solving the problem]

[0010] To achieve the above objective, a vehicle body corrosion prediction method according to one embodiment of the present invention includes: a vehicle body shape model construction step of constructing a vehicle body shape model in which the shape of the vehicle body is represented by a two-dimensional mesh formed by a plurality of plate-like elements including data on position and inclination angle on the vehicle body, based on vehicle data of a target vehicle for which corrosion prediction is to be performed; a peripheral region shape model construction step of constructing a peripheral region shape model in which the peripheral region surrounding the vehicle body is represented by a three-dimensional mesh formed by a plurality of polyhedral elements; an association step of associating data relating to factors that cause the vehicle body to corrode when the vehicle is assumed to have been used in a predetermined area for a predetermined period of time with the plurality of polyhedral elements of the peripheral region shape model; a unit time corrosion degree calculation step of calculating the corrosion degree per unit time for each plate-like element from the corrosion action conditions associated with the polyhedral elements of the peripheral region shape model and data relating to the position and inclination angle of the plate-like elements of the vehicle body shape model; and a corrosion degree calculation step of calculating the corrosion degree of the vehicle body after a predetermined period of time has elapsed based on the calculated corrosion degree per unit time.

[0011] Furthermore, in order to achieve the above objective, a vehicle body corrosion prediction system according to one embodiment of the present invention is characterized by comprising: an acquisition unit that acquires vehicle data of a target vehicle for which corrosion prediction is to be performed and environmental data including data on factors that cause corrosion of the vehicle body when it is assumed that the vehicle was used in a predetermined area for a predetermined period of time; a shape model construction unit that constructs a shape model of the vehicle body in which the shape of the vehicle body is represented by a two-dimensional mesh formed by a plurality of plate-like elements including data on position and inclination angle on the vehicle body, and constructs a shape model of the surrounding area that surrounds the vehicle body in which a three-dimensional mesh formed by a plurality of polyhedral elements is represented; and a calculation unit that associates data on the factors that cause corrosion with the plurality of polyhedral elements of the shape model of the surrounding area, calculates the degree of corrosion per unit time for each plate-like element from the corrosion action conditions associated with the polyhedral elements and data on the position and inclination angle of the plate-like elements of the shape model of the vehicle body, and calculates the degree of corrosion of the vehicle body after a predetermined period of time has elapsed based on the calculated degree of corrosion per unit time.

[0012] Furthermore, in order to achieve the above objective, one embodiment of the present invention is a vehicle body corrosion prediction program configured to be readable by an information processing device and predicting the degree of corrosion occurring on a vehicle body, comprising: a vehicle body shape model construction step of constructing a vehicle body shape model in which the shape of the vehicle body is represented by a two-dimensional mesh formed by a plurality of plate-like elements including position and inclination angle data on the vehicle body, based on vehicle data of the target vehicle for which corrosion prediction is to be performed; a peripheral region shape model construction step of constructing a peripheral region shape model in which the peripheral region surrounding the vehicle body is represented by a three-dimensional mesh formed by a plurality of polyhedron elements; and a predetermined period of time in a predetermined region where the vehicle is The information processing device is characterized by causing the following to be executed: an association step of associating data relating to factors that would corrode the vehicle body if it were used with the plurality of polyhedral elements of the shape model of the surrounding area; a unit time corrosion degree calculation step of calculating the corrosion degree per unit time for each plate-like element from the corrosion action conditions associated with the polyhedral elements of the shape model of the surrounding area and data relating to the position and inclination angle of the plate-like elements of the shape model of the vehicle body; and a corrosion degree calculation step of calculating the corrosion degree of the vehicle body after a predetermined period of time has elapsed based on the calculated corrosion degree per unit time. [Effects of the Invention]

[0013] According to the vehicle body corrosion prediction method, vehicle body corrosion prediction system, and vehicle body corrosion prediction program of the present invention, it is possible to accurately predict vehicle body corrosion for newly designed vehicles. [Brief explanation of the drawing]

[0014] [Figure 1] This is a block diagram showing a vehicle body corrosion prediction system according to one embodiment of the present invention. [Figure 2] This is a perspective view showing the vehicle body shape model and the shape model of the area surrounding the vehicle body. [Figure 3] Figure 2 is an explanatory diagram showing the shape model in a planar view. [Figure 4] This is a perspective view illustrating the plate-like elements that make up the vehicle body shape model. [Figure 5] This figure shows a matrix table of coefficients used in the polynomial formula for calculating corrosion rate. [Figure 6] This is a flowchart showing the procedure for corrosion prediction. [Modes for carrying out the invention]

[0015] Hereinafter, one embodiment of the present invention will be described with reference to the drawings. Figure 1 is a block diagram showing a vehicle body corrosion prediction system 10 according to one embodiment of the present invention. Vehicles such as automobiles experience corrosion on their bodies due to exposure to rain and salt over many years of use. The corrosion prediction system 10 predicts the degree of corrosion on the vehicle body caused by such use by simulating it on a computer. The vehicle body corrosion prediction system 10 can be composed of an information processing device, which can be a single computer such as a microcomputer or a personal computer, or a plurality of computers interconnected via a network.

[0016] The vehicle body corrosion prediction system 10 comprises an input device 12 which is an input means for inputting information, an external storage device 14 which is a storage means, a processing unit 16 which constitutes a control means and a calculation means, and a display device 18 which is a display means.

[0017] The input device 12 can be configured as, for example, a keyboard, mouse, and / or touch panel. The external storage device 14 is an external memory connected to the arithmetic processing unit 16 and can be configured as a storage device such as an HDD (hard disk drive) or SSD (solid state drive). The input device 12 and / or the external storage device 14 constitute an acquisition unit that acquires vehicle data and environmental data, which will be described later.

[0018] The arithmetic processing unit 16 is a computer including a microcomputer, and includes a central processing unit (CPU) which is an information processing unit, internal memory such as RAM and ROM which constitute storage means, and input / output interfaces for communicating with other devices. The information processing unit of the arithmetic processing unit 16 is not limited to a CPU, but can be, for example, a field-programmable gate array (FPGA), an application-specific integrated circuit (ASIC), an application-specific standard product (ASSP), a system on a chip (SOC), etc.

[0019] The arithmetic processing unit 16 can execute a vehicle corrosion prediction program stored in its internal memory, a vehicle corrosion prediction program recorded on a recording medium readable via the external storage device 14, or a vehicle corrosion prediction program loaded from an external source via a network or communication device (not shown) using its CPU. By executing this corrosion prediction program, the arithmetic processing unit 16 simulates the degree of corrosion that will occur on the vehicle body by exposing the vehicle, which is the target of the prediction as instructed by the input device 12, to the environment of a simulated vehicle usage area.

[0020] The arithmetic processing unit 16 includes a storage unit 21 which is an internal memory, a shape model construction unit 22, an arithmetic unit 24, and a counter unit 26.

[0021] The storage unit 21 can store data that has been taken into the arithmetic processing unit 16 via the input device 12 or the external storage device 14. In this embodiment, data relating to the target vehicle for which corrosion prediction is to be performed (hereinafter also referred to as "vehicle data") and data relating to the environment of the area in which the vehicle is used (hereinafter also referred to as "environmental data") are input to the arithmetic processing unit 21 via the input device 12, etc., and this data is stored in the storage unit 21.

[0022] Vehicle data includes vehicle body design data, data on the materials of vehicle body parts, and data on electrodeposited coatings and chemical conversion coatings formed on the surfaces of the panel members that make up the vehicle body (e.g., data on the components and thickness of the coatings and films). Environmental data includes data on factors that corrode the vehicle body, assuming that the vehicle is used in a given area for a given period of time. Here, data on factors that corrode the vehicle body includes, for example, weather in the area where the vehicle is used (e.g., temperature, humidity, precipitation, snowfall), the amount of de-icing salt spread on the roads, and the presence and amount of stones on the roads.

[0023] As shown in Figures 2 and 3, the shape model construction unit 22 constructs the shape of the vehicle body based on vehicle data, including a plurality of plate-like elements E, which include data on the position and inclination angle of the vehicle body. i A two-dimensional mesh formed by this process is used to construct a vehicle body shape model 30 (hereinafter also referred to as "vehicle body shape model 30"). The shape model construction unit 22 also uses multiple polyhedral elements P to represent the surrounding area of ​​the vehicle body. i A shape model 40 of the surrounding region (hereinafter also referred to as the "surrounding region shape model 40") is constructed using a three-dimensional mesh formed by the above. The shape model 40 of the surrounding region includes a first surrounding region 42 adjacent to the vehicle body shape model 30 and a second surrounding region 44 surrounding the first surrounding region 42.

[0024] As shown in Figure 4, the vehicle body shape model 30 is constructed by using the finite element method to form multiple plate-shaped elements E i This is represented as a two-dimensional numerical computation model by dividing it into integers (i=1 to N). Plate-shaped element E i The surface shape can be a triangle, a quadrilateral, or other polygon. Each plate-like element E of the vehicle body shape model 30 i At each vertex, a node ai (i = integer from 1 to n) is located, and for each node ai, the X, Y, and Z coordinate values ​​are specified. The XYZ Cartesian coordinate system is a fixed coordinate system for the object of analysis, and in this embodiment, it is pre-set so that the vehicle body of the object of analysis is horizontal and the Z axis is in the direction of gravity G.

[0025] For each plate element E of the vehicle body shape model 30 i , the inclination angle of the outer surface with respect to the gravity direction G is specified together with position data based on a coordinate system. For each plate element E i , in addition to position data and inclination angle data in the XYZ orthogonal coordinate system, the plate element E holds data relating to thickness (plate thickness) and an electrodeposition coating film and / or a chemical conversion film formed on the surface (for example, data such as film components and film thickness).

[0026] As shown in FIG. 3, the surrounding region shape model 40 is expressed as a three-dimensional numerical calculation model by dividing a region surrounding the vehicle body into a plurality of polyhedral elements P i (where i is an integer from 1 to M). Each vertex of each polyhedral element has its X coordinate value, Y coordinate value, and Z coordinate value specified in the same XYZ orthogonal coordinate system as that of the vehicle body shape model 30, so that the position of each polyhedral element can be specified. Additionally, in conjunction with or instead of this, a configuration may be adopted in which each polyhedral element is assigned a number to specify its position.

[0027] As described above, the surrounding region shape model 40 includes a first surrounding region 42 and a second surrounding region 44. The three-dimensional mesh of the second surrounding region 44 is formed of polyhedral elements P having a larger volume than the three-dimensional mesh of the first surrounding region 42, so that the three-dimensional mesh of the second surrounding region 44 is coarser than that of the first surrounding region 42 i . In the following description, the polyhedral elements P constituting the first surrounding region 42 i are referred to as "polyhedral elements P1 i ", and the polyhedral elements P constituting the second surrounding region 44 i are referred to as "polyhedral elements P2 i ".

[0028] The calculation unit 24 associates environmental data with the plurality of polyhedral elements P of the surrounding region shape model 40 i , and calculates the degree of corrosion per unit time for each plate element E i based on the corrosion action conditions associated with the polyhedral elements P and the data relating to the position and inclination angle of the plate elements E i of the vehicle body shape model 30 i .

[0029] In this embodiment, based on environmental data, the polyhedron element P1 of the second peripheral region 44 of the peripheral region shape model 40 i The corrosion conditions are set for the second peripheral region 44, and then, based on these corrosion conditions for the second peripheral region 44, the polyhedral element P of the first peripheral region 42 is determined. i More detailed corrosion conditions are set. Polyhedral element P2 of the second peripheral region 44 i In this system, weather data (e.g., temperature, humidity, precipitation, snowfall, etc.) and road surface data (e.g., amount of de-icing salt spread on the road, presence or absence of stones on the road, etc.) in the area where the vehicle is used are set as corrosion conditions. Polyhedral element P1 of the first peripheral region 42 i Based on weather data and road surface data set in the second surrounding area 44, data relating to the amount of corrosion factors and the entry speed of corrosion factors (for example, data such as the amount of rain or snow, the weight of stones hitting the vehicle body, the speed at which rain or snow hits the vehicle body, and the speed at which stones hit the vehicle body) are set as corrosion conditions.

[0030] Furthermore, in this embodiment, the calculation unit 24 calculates the corrosion rate as the degree of corrosion per unit time, and assuming a unit time of 1 day, the corrosion rate per day (unit: mm / day) is calculated for the plate-shaped element E i The calculation is performed for each period. The daily corrosion rate is the thickness of the plate that decreases per day due to corrosion. Note that the unit time is not limited to one day; it can be set as appropriate, for example, three days or one month.

[0031] Polyhedron elements P of the peripheral region shape model 40 generated by the calculation unit 24 i Associating environmental data with polyhedron element P i The setting of corrosion conditions for the element is performed at unit time intervals. The counter unit 26 calculates the total plate element E using the calculation unit 24. i Each time the calculation of the corrosion rate per unit time is completed, the unit time is added. Based on the count period by the counter unit 26, the calculation unit 24 calculates the polyhedral element P from the environmental data. iSelect the data to associate with the condition and calculate the corrosion rate per unit time.

[0032] For example, if the predetermined period for corrosion prediction is 15 years and the unit time is 1 day, first the counter unit 26 adds 1 day, which is the unit time. Based on the count period by the counter unit 26, the calculation unit 24 calculates the environmental data for the first day for each polyhedral element P of the surrounding region shape model 40. i Associated with and based on the associated corrosion conditions, each plate-like element E i The corrosion rate for day 1 is calculated. Once the corrosion rate calculation is complete, the counter unit 26 adds 1 day, which is the unit time. Based on the counting period (2 days) by the counter unit 26, the calculation unit 24 calculates the environmental data for day 2 for each polyhedral element P of the surrounding region shape model 40. i Associated with and based on the associated corrosion conditions, each plate-like element E i The corrosion rate on the second day is calculated for this. In this way, the conditioning based on environmental data and the calculation of the corrosion rate based on these conditions are repeated for the third day, fourth day, ..., x day, and so on, to calculate the corrosion rate for 15 years (i.e., 5478 days). As another example, if the unit time is 3 days, the calculation unit 24 calculates the environmental data for 3 days for the polyhedron element P i The corrosion rate is calculated based on the associated corrosion conditions over a three-day period.

[0033] The corrosion rate calculated by the calculation unit 24 can be calculated, for example, by a polynomial that adds or subtracts terms obtained by multiplying a coefficient by a variable representing the factors that cause corrosion of the vehicle body. As an example, in this embodiment, the corrosion rate is calculated by the following equation (1).

[0034] Corrosion rate (unit: mm / day) = a0 + (a1 × T) + (a2 × H) - (a3 × Th1) - (a4 × Th2) - (a5 × E) - (a6 × C) + (a7 × Mw) + (a8 × Ms) + (a9 × Msn) + (a 10 ×Tc)+(a 11 ×M)...Equation (1)

[0035] In equation (1), a0 ~ a11 is a coefficient. In equation (1), T is temperature, H is humidity, Th1 is the thickness of the electrodeposited coating, Th2 is the thickness of the chemical conversion coating, E is the components of the electrodeposited coating, C is the components of the chemical conversion coating, Mw is the amount of water, Ms is the amount of salt, Msn is the amount of snow, Tc is the chipping rate indicating the amount of damage caused by impact with stones, and M is the material.

[0036] In equation (1), temperature T (unit: °C), humidity H (unit: %), and water volume Mw (plate element E) are used. i Thickness of water adhering to the surface (unit: mm), Salt content Ms (concentration of salt per unit of water, unit: %), Snow content Msn (plate element E i The thickness of snow adhering to the surface (unit: mm) and the chipping rate Tc (stone is a plate-like element E) i The percentage of the surface area, in units of %), is determined per unit time based on environmental data. For example, temperature T can be the average temperature for the day.

[0037] Furthermore, in equation (1), the electrodeposition film thickness Th1 (unit: μm), the chemical conversion treatment film thickness Th2 (unit: μm), the electrodeposition coating component E, the chemical conversion coating component C, and the material M are determined based on vehicle data. The electrodeposition coating component E, the chemical conversion coating component C, and the material M can be qualitative variables. For example, the electrodeposition coating component E and the chemical conversion coating component C can be set to "1" when the rust prevention performance is low and to "1.2" when the rust prevention performance is high. The material M is an iron-aluminum alloy material, a resin material, etc. For example, it can be set to "1" for an iron-aluminum alloy material that corrodes due to the natural electrode potential, and to "0" for a resin material that does not corrode. One plate-like element E i In this case, the values ​​of film thickness Th1, film thickness Th2, component E, component C, and material M may be kept constant for the duration of the corrosion prediction period.

[0038] Each coefficient a0~a 11 The value of is the plate-like element E i Each is selected from a pre-configured matrix table. Figure 5 shows an example of a matrix table, where the numbers are listed in alphabetical order from smallest to largest. For example, for coefficient a1, a 1A 1B <a​1C 1D 1E In Figure 5, each coefficient a0 to a 11 Five numerical values, A to E, are assigned to each coefficient, but the number of values ​​is not limited to five. For example, one value may be assigned to coefficient a0, three to coefficient a1, and so on. 11 Multiple values ​​are set for the plate-like element E in the vehicle body model 30. i Depending on the position and tilt angle, each coefficient a1~a is selected from the matrix table. 11 A numerical value is selected for each element. For example, for the plate-like element E 10 If the plate-like element E is located below the vehicle body and the angle of inclination of its surface is close to horizontal, 10 This is a plate-like element E on a vertical surface located above the vehicle body. 20 Compared to the other, water tends to accumulate more easily, so the value of the coefficient a8 of the water volume Mw becomes larger. In such cases, the calculation unit 24 considers the coefficient a8 in equation (1) for example, the plate-shaped element E 10 For coefficient a 8E Select plate element E 20 For coefficient a 8B (a 8B 8E Select the coefficient a0~a 11 is a plate-like element E i The selection is made from a matrix table depending on the position and tilt angle.

[0039] The coefficients a0 to a in the matrix table in Figure 5 11 The values ​​are set based on the results of experiments conducted in advance. From the experiment, each coefficient a0~a 11 When setting this, in equation (1), make sure that the unit of each term is "mm / day" from a0 to a 11 The dimension is set. Note that in equation (1), the coefficient a0 is an initial value, and for example, "coefficient a0 = 0".

[0040] ​​​Furthermore, the calculation unit 24 calculates the degree of corrosion of the vehicle body after a predetermined period has elapsed, based on the calculated degree of corrosion per unit time. Specifically, until the counting period by the counter unit 26 reaches a predetermined period, the calculation unit 24 calculates the corrosion rate per unit time and sums these up for the predetermined period. As a result, each plate-shaped element E i The degree of corrosion after a predetermined period is calculated, and it is possible to determine how much corrosion has progressed for each plate-like element of the vehicle body (i.e., each part of the vehicle body) after the predetermined period has elapsed.

[0041] The simulation results of the degree of corrosion of the vehicle body after a predetermined period, calculated by the processing unit 16, are displayed on the display device 18. The display device 18 is a device capable of visually displaying information and can be composed of, for example, a liquid crystal display, an organic EL display, a plasma display, and / or a cathode ray tube display.

[0042] Next, the method for predicting vehicle body corrosion using the vehicle body corrosion prediction system 10 of this embodiment will be explained using the flowchart shown in Figure 6.

[0043] First, in step S11, various calculation condition data are input to the arithmetic processing unit 16 by the input device 12 and / or external storage device 14 (data acquisition step). Here, the calculation condition data includes the vehicle data and environmental data mentioned above.

[0044] In the next step S12, the shape model construction unit 22 constructs a vehicle body shape model 30 on the computer based on the input vehicle data (vehicle body shape model construction process). Each plate-shaped element E of the vehicle body shape model 30 i This data associates the plate thickness with the thickness and composition of the electrodeposited coating and / or chemical conversion coating formed on the surface.

[0045] In the next step S13, the shape model construction unit 22 constructs a peripheral region shape model 40 surrounding the vehicle body shape model 30 on the computer (peripheral region shape model construction step). As previously described, the peripheral region shape model 40 includes a first peripheral region 42 and a second peripheral region 44.

[0046] In the next step S14, the count period t of the counter unit 26 is set to the initial value t0 (t=t0). In this embodiment, the initial value t0 is the elapsed period of 0 days.

[0047] In the next step S15, a predetermined unit time Δt is added to the counting period of the counter unit 26 (t=t+Δt). In this embodiment, one day, which is the unit time, is added.

[0048] In the next step, S16, the environmental data is processed into multiple polyhedral elements P of the surrounding region shape model 40. i Associate with (association process). Specifically, the environmental data for the period added to the counter unit 26 in step S15 is associated with the peripheral region shape model 40, and corrosion action conditions are set for the peripheral region shape model 40. As previously described, in this embodiment, the second peripheral region 44 polyhedron element P2 of the peripheral region shape model 40 i Weather data and road surface data from the vehicle's operating area are incorporated as data for corrosion conditions. Based on the incorporated weather and road surface data, the amount of corrosion factors and the rate of corrosion factor entry are calculated for the vehicle body shape model 30, and these are applied to the polyhedral element P1 of the first peripheral region 42. i This is set as a corrosive condition.

[0049] In the next step, S17, the polyhedron element P of the surrounding region shape model 40 is... i Corrosion conditions associated with and plate-like element E of vehicle body shape model 30 i Based on the position and inclination angle data that the plate-shaped element E has, the calculation unit 24 calculates i The corrosion rate is calculated for each step (unit time corrosion rate calculation step). In this embodiment, the calculation unit 24 calculates the corrosion rate per day using the formula (1) described above.

[0050] All plate-like elements E i Once the calculation of the corrosion rate for is complete, the next step S18 is performed, and the arithmetic processing unit 16 determines that the counting period t by the counter unit 26 is the predetermined period t for corrosion prediction. P Determine whether the period has reached a certain point. For example, if the predetermined period for corrosion prediction is 15 years (5478 days), determine whether the count period t has reached 5478 days. P If the condition is not met (Step S18: No), proceed to Step S15, add the unit time Δt to the count period, and then proceed to the following Step S16.

[0051] In step S18, the counted period t becomes a predetermined period t P If the condition is met (Step S18: Yes), the process proceeds to Step S19, and the calculation unit 24 calculates the corrosion rate per unit time for a predetermined period t P By adding up the minutes, each plate element E i The degree of corrosion after a predetermined period is calculated (corrosion degree calculation process). For example, if the predetermined period for corrosion prediction is 15 years (5478 days), the corrosion rate from day 1 to day 5478 is added up to calculate the amount of corrosion after 5478 days. This makes it possible to calculate the amount of corrosion that occurs in each part of the vehicle body after 15 years, that is, the amount by which the thickness of the panel parts that make up the vehicle body decreases.

[0052] In the next step S20, a predetermined period t P The simulation results of the amount of corrosion of the vehicle body after the passage of time, i.e., the predicted corrosion results of the vehicle body, are displayed on the display device 18.

[0053] As described above, according to the corrosion prediction method of this embodiment, a vehicle body shape model 30 and a surrounding area shape model 40 are constructed on a computer, and the corrosion action conditions that cause the vehicle body to corrode are determined by each polyhedral element P of the surrounding area shape model 40. i By relating and digitizing the data, the plate-shaped element E of the vehicle body shape model 30 iThe corrosion rate can be calculated for each plate-shaped element E of the vehicle body shape model 30. i Each of these has data set for its position and inclination angle on the vehicle body, so plate-shaped element E i The corrosion status can be understood for each environment. And, plate-shaped element E i By calculating the degree of corrosion per predetermined unit time for each vehicle, it is possible to obtain a corrosion rate that corresponds to changes in the vehicle's operating environment. Based on this, it is possible to accurately predict the amount of corrosion on the vehicle body by calculating the degree of corrosion after a desired period of time has elapsed. As a result, even when there are changes in the shape of the vehicle body, such as when a new vehicle body is designed, the degree of corrosion on the vehicle body can be predicted with high accuracy.

[0054] Furthermore, in the corrosion prediction method of this embodiment, the peripheral region shape model 40 is divided into two peripheral regions. Weather data and road surface data of the vehicle usage area are incorporated into the second peripheral region 44, while in the first peripheral region 42, which is close to the vehicle body, data on the amount of corrosion factors and entry speed based on the weather data and road surface data are set as corrosion action conditions. In this case, since the second peripheral region 44 is composed of polyhedral elements with a larger volume than the first peripheral region 42, the amount of data during calculation processing can be reduced. Also, the amount of data in the first peripheral region 42 can be increased to improve the corrosion prediction accuracy. In this way, by dividing the peripheral region shape model 40 into regions with different mesh coarseness and changing the amount of data, it is possible to improve the corrosion prediction accuracy while suppressing an increase in the overall amount of data and shortening the calculation processing time.

[0055] Furthermore, if the shape of the vehicle body changes, the corrosion prediction of the vehicle body can be performed by changing only the data of the first peripheral region 42 and the vehicle body shape model 30, without changing the data of the second peripheral region 44 of the peripheral region shape model 40. Therefore, when predicting corrosion for multiple types of vehicles with different shapes under the same operating environment, it is possible to shorten the calculation processing time by using the corrosion action conditions in the second peripheral region 44 in combination.

[0056] Furthermore, in the corrosion prediction method of this embodiment, the corrosion rate is calculated by a polynomial obtained by adding or subtracting terms obtained by multiplying coefficients and the amount of the corrosive factor, i.e., numerical values, for each corrosion factor. Therefore, the corrosion rate can be calculated by a simple calculation. Each coefficient a0 to a in the polynomial 11 is a plate-like element E i Since the likelihood of corrosion varies depending on the location and inclination angle on the vehicle body, and is selected from a pre-set matrix table accordingly, it is possible to simplify the calculation formula for the corrosion rate and shorten the calculation processing time while maintaining high accuracy in corrosion prediction.

[0057] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention.

[0058] For example, in the embodiment described above, the peripheral region shape model 40 is divided into two regions, the first and second peripheral regions 42 and 44, and corrosion conditions are set for each peripheral region 42 and 44. However, it is also possible to set conditions based on environmental data without dividing the regions. [Explanation of Symbols]

[0059] 10. Corrosion prediction system 12 Input devices 14 External storage device 16 Arithmetic Processing Unit 18 Display device 21 Memory section 22 Shape Model Construction Section 24 Arithmetic section 26 Counter section 30 Body shape model 40. Shape model of the surrounding region 42 First peripheral region 44 Second peripheral region ai node E i Plate-like element P i polyhedral element P1 i Polyhedron elements of the first peripheral region P2i Polyhedron elements of the second peripheral region

Claims

1. A vehicle shape model construction step involves constructing a vehicle shape model that represents the shape of the vehicle body using a two-dimensional mesh formed by multiple plate-like elements including data on the position and inclination angle of the vehicle body, based on vehicle data of the target vehicle for corrosion prediction. A peripheral region shape model construction step involves constructing a peripheral region shape model that represents the peripheral region surrounding the vehicle body using a three-dimensional mesh formed by multiple polyhedral elements, A correlation step involves associating data relating to factors that cause corrosion of the vehicle body when the vehicle is used in a predetermined area for a predetermined period of time with the plurality of polyhedral elements of the shape model of the surrounding area, A unit time corrosion rate calculation step, which calculates the corrosion rate per unit time for each plate-shaped element based on the corrosion conditions associated with the polyhedral elements of the shape model of the surrounding region and data relating to the position and inclination angle of the plate-shaped elements of the shape model of the vehicle body, A corrosion degree calculation step that calculates the corrosion degree of the vehicle body after a predetermined period of time based on the calculated corrosion degree per unit time, A method for predicting corrosion of a vehicle body, characterized by including the following:

2. The shape model of the surrounding region includes a first surrounding region adjacent to the shape model of the vehicle body, and a second surrounding region surrounding the first surrounding region. The method for predicting corrosion of a vehicle body according to claim 1, characterized in that the three-dimensional mesh of the second peripheral region is formed of polyhedral elements with a larger volume than the three-dimensional mesh of the first peripheral region.

3. The aforementioned degree of corrosion per unit time is the corrosion rate. In the above-mentioned process for calculating the degree of corrosion per unit time, The aforementioned corrosion rate is calculated by a polynomial that adds or subtracts terms obtained by multiplying a coefficient by a variable representing the factors that cause the vehicle body to corrode. The method for predicting corrosion of a vehicle body according to claim 1 or 2, characterized in that the coefficient is selected for each plate-like element from a pre-set matrix table.

4. An acquisition unit that acquires vehicle data of a target vehicle for which corrosion prediction is to be performed, and environmental data including data on factors that would corrode the vehicle body if the vehicle were used in a predetermined area for a predetermined period of time, A shape model construction unit constructs a shape model of a vehicle body, representing the shape of the vehicle body with a two-dimensional mesh formed by multiple plate-like elements including data on position and inclination angle within the vehicle body, and constructs a shape model of the surrounding area, representing the surrounding area with a three-dimensional mesh formed by multiple polyhedral elements. A calculation unit that associates data relating to the corrosive factors with the plurality of polyhedral elements of the shape model of the surrounding region, calculates the degree of corrosion per unit time for each plate-shaped element from the corrosion conditions associated with the polyhedral elements and data relating to the position and inclination angle of the plate-shaped elements of the shape model of the vehicle body, and calculates the degree of corrosion of the vehicle body after a predetermined period of time based on the calculated degree of corrosion per unit time, A vehicle body corrosion prediction system characterized by having the following features.

5. In a vehicle body corrosion prediction program configured to be readable by an information processing device and predicting the degree of corrosion occurring on the vehicle body, A vehicle shape model construction step involves constructing a vehicle shape model that represents the shape of the vehicle body using a two-dimensional mesh formed by multiple plate-like elements including data on the position and inclination angle of the vehicle body, based on vehicle data of the target vehicle for corrosion prediction. A peripheral region shape model construction step involves constructing a peripheral region shape model that represents the peripheral region surrounding the vehicle body using a three-dimensional mesh formed by multiple polyhedral elements, A correlation step of associating data relating to factors that cause corrosion of the vehicle body when the vehicle is used in a predetermined area for a predetermined period of time with the plurality of polyhedral elements of the shape model of the surrounding area, A unit time corrosion rate calculation step, which calculates the corrosion rate per unit time for each plate-shaped element based on the corrosion conditions associated with the polyhedral elements of the shape model of the surrounding region and data relating to the position and inclination angle of the plate-shaped elements of the shape model of the vehicle body, A corrosion degree calculation step that calculates the degree of corrosion of the vehicle body after a predetermined period of time based on the calculated degree of corrosion per unit time, A vehicle body corrosion prediction program characterized by causing the information processing device to execute the following.

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