JP5797071B2 - Heating method calculation method for linear heating - Google Patents

Description

  The present invention relates to a heating method calculation method for linear heating that determines a heating wire arrangement and heating conditions for bending a metal plate by linear heating, such as a steel plate used for an outer shell of a ship.

  Shipboard bend processing is performed at most shipyards throughout Japan by the operator's skill called flexing iron or linear heating. However, more than ten years of work experience are required to acquire skills at a level capable of processing a curved surface with a large bend or a complicated curved surface, such as a bow stern skin. Moreover, in the construction of one large ship, the amount of bending work requiring such high skill occupies 50 to 60% of the entire bending work. Therefore, a large number of highly skilled technicians must be secured for the construction of the ship, which is a heavy burden for the shipbuilding industry and has become a more prominent problem due to the lack of successors in recent years.

  Therefore, in recent years, a method of mechanically performing linear heating has been proposed (see, for example, Patent Document 1). As a method for mechanically performing such linear heating, a finite element method (FEM) is applied to divide the surface of the metal plate to be bent into a large number of regions and bend the target shape for each divided region. In order to obtain the target inherent strain required for the purpose, and to provide the in-plane shrinkage strain component and the bending strain component of the target inherent strain, for example, by arranging the curved heating in the divided region on one surface of the metal plate, While the heating source is moved along the area, the heating speed of the heating source is locally controlled so as to obtain a predetermined heat input amount as a control parameter, whereby each divided region is bent into the target shape and the entire metal plate is curved with the target shape. There is a method of forming.

  In addition, in the method described in Patent Document 1, as a technique for predicting deformation of a steel structure due to welding, a pre-investigation is performed on the assumption that the relationship between heat input and plastic deformation when the heating source moves can be regarded as constant. And then apply a method (inherent strain method) that predicts the overall deformation shape by linearly adding such data as input, and search for heating conditions (combination of heating position and heating speed) that give the target shape. The automatic linear heating method is used, which calculates backwards with a typical calculation method. This method provides an automatic linear heating method that calculates a heating method that gives a target shape by calculation, and has been put to practical use as the only automated example in the world of hull skin bending. The heating condition based on the combination of the heating position and the heating rate is particularly called a “heating plan”, and the heating plan may include a heating order.

Japanese Patent Laid-Open No. 2003-211230

  However, for example, in curved surfaces and thick plates with large bends that make up the stern outer plate, the heating lines tend to be dense, and the relationship between heat input and plastic deformation described above does not hold especially in places where they intersect or overlap. It has turned out.

  For example, if a heating source is placed on the surface of a steel plate (metal plate) on a thick plate having a thickness of 25 mm or more and subjected to bending, the currently available heating source can be plastically deformed to the back surface of the steel plate. It is difficult to heat to a sufficient temperature, and a large residual stress remains in the vicinity of heating after cooling. When the vicinity of this heating is reheated, the residual stress is released, and plastic deformation far from the case where the two heatings are applied independently is created.

  Moreover, in order to make a curved surface with a large bend from a flat plate, it is necessary to apply a large shrinkage. Also in this case, residual stress is accumulated around the previously applied heating wire, and the plastic deformation produced by the heating wire to be applied later in the vicinity thereof is greatly different from the plastic deformation of the independent heating wire.

  Therefore, the assumption that the sum of the plastic deformations of each heating wire forms a shape does not hold, and the deformation when two heating wires are applied close to each other is the estimated deformation of each one. The difference greatly differs from the sum, and the variation shows various modes depending on the combination of heating conditions. Due to this local variation of the heated heating line, it is difficult to automate the bending of a curved surface with a large bend that has the highest need for automation.

  By the way, there is a simulation by a thermoelastic-plastic finite element method as a method for accurately estimating “deformation due to heating” which is the key to automation. If this method is used, it is possible to estimate the deformation of the heating wire applied in close proximity. However, with the current computing power of a computer, it is difficult to execute a calculation of a large number of complicated heating lines in parallel with the heating work, which is not realistic. Further, it is almost impossible to repeat this method many times in order to perform an optimization search for obtaining a heating condition that gives a target shape.

  The present invention was devised in view of the above-mentioned problems, and even when it is a thick plate or a case where heating wires are densely packed, the deformation can be accurately predicted in a practical time. An object of the present invention is to provide a heating method calculation method for linear heating, which can calculate a heating method capable of forming a target shape based on prediction.

  According to the present invention, the lattice model creating step of creating a lattice model for the finite element method indicating the target shape to be created by heating, and the target shape is forcibly deformed into a planar shape using the finite element method, A target inherent strain calculating step for calculating a target inherent strain which is a strain distribution capable of forming the target shape from the planar shape by forcibly deforming the planar shape into the target shape, and an arrangement of a heating wire approximating the target inherent strain A heating plan calculation step for setting a heating plan including a heating rate and a heating order, and a heating plan calculation method for linear heating, in which heating conditions for the interference pattern of the interference portion where the heating lines are dense and the heating line A correction database creation step of measuring a variation amount from a standard value of deformation due to a correction database and a heating database calculation step before the heating plan calculation step A variation amount calculation step of extracting a correction target heating line corresponding to the interference pattern from the heating method, and calculating the variation amount of the correction target heating line based on the correction database, and the variation amount calculation step A corrected deformation amount calculating step of calculating a corrected deformation amount by adding the changed amount to the heating method, and a heating method recalculating the corrected heating method by recalculating the heating method based on the corrected deformation amount. There is provided a heating method calculation method for linear heating, characterized by comprising a calculation step.

  The interference pattern is, for example, parallel, superimposed, oblique, or orthogonal. Further, the correction database has, for example, a heating order, a heating speed, a heating surface, an arrangement interval, the number of overlapping times, or an intersection angle with respect to the interference pattern as a parameter.

  When the heating sequence parameter in the correction database includes the first heating line and the second heating line that form the interference pattern, the heating sequence parameter of the first heating line and the second heating line is a condition value. May be included.

  When the heating rate parameter in the correction database includes a first heating line and a second heating line that form the interference pattern, a combination of a heating rate of the first heating line and a heating rate of the second heating line May be included as a condition value.

  When the heating surface parameter in the correction database includes the first heating line and the second heating line that form the interference pattern, the first heating line and the second heating line exist on the same surface or the opposite surface. It may be included as a condition value.

  The arrangement interval parameter in the correction database may include, as a condition value, a distance from the nearest heating line that is pre-heated when the interference pattern has a plurality of heating lines formed by the interference pattern.

  The superposition number parameter in the correction database is a case where the interference pattern is superposed, and may include the number of superposed heating lines as a condition value.

  The crossing angle parameter in the correction database is the case where the interference pattern is oblique and includes the first heating line and the second heating line that form the interference pattern, and the first heating line and the second heating line. An angle formed by the two heating lines may be included as a condition value.

  In the correction database, a table may be formed for each strain component of lateral contraction, lateral bending deformation, vertical contraction, or vertical bending deformation.

  The heating method recalculation step is based on the difference between the generated inherent strain and the target inherent strain which is a strain distribution formed based on the corrected deformation amount until the heating method is recalculated as many times as necessary. It may include repeating the recalculation of the heating method until the value is less than or equal to the value. The reference value is, for example, such that the difference between the generated inherent strain and the target inherent strain is 5 to 10% of the target inherent strain.

  The correction heating method may be calculated by recalculating at least the heating rate.

  According to the heating method calculation method for linear heating according to the present invention described above, paying attention to the interference pattern of the heating wire, a correction database corresponding to this interference pattern is created, and the heating method is corrected using this correction database. By doing so, even when the target metal plate is a thick plate or when the heating wire is dense, the deformation can be accurately predicted, and the target shape can be formed based on the prediction An excellent heating strategy can be calculated.

  Therefore, real-time calculation is difficult and expensive using a large-scale calculation environment for the automation of advanced bending processes such as the stern structure that could not be processed with the current automatic bending system despite high demand. Without using a non-linear simulation, the present automatic bending system, which is a linear addition system, can be easily realized by simply expanding it.

It is a flowchart which shows the heating method calculation method of the linear heating which concerns on 1st embodiment of this invention. It is the conceptual diagram of the steel plate in the flowchart shown in FIG. 1, (a) is the lattice model of a target shape, (b) is the planar shape of the lattice model formed using a finite element method, (c) was calculated. It is a figure which shows arrangement | positioning of a heating wire. It is explanatory drawing which shows an interference pattern, (a) is parallel, (b) is superimposition, (c) shows diagonal, (d) has shown orthogonality. It is a conceptual explanatory view of the amount of variation by orthogonal heating, (a) is heating by the first heating wire, (b) is heating by the second heating wire, (c) is shrink deformation in the Y-axis direction, (d) is X Axial contraction deformation is shown. It is a figure which shows an example of the table of the correction | amendment database in orthogonal heating, (a) is the fluctuation | variation table of lateral contraction with respect to the 1st heating line of the same surface heating, (b) is lateral contraction with respect to the 2nd heating line of the same surface heating. The fluctuation table, (c) is a fluctuation table of lateral contraction with respect to the first heating line of the opposite surface heating, and (d) is a fluctuation table of lateral contraction with respect to the second heating line of the opposite face heating. It is a flowchart which shows the heating method calculation method of the linear heating which concerns on 2nd embodiment of this invention.

  Hereinafter, the heating method calculation method of the linear heating which concerns on embodiment of this invention is demonstrated using FIGS. Here, FIG. 1 is a flowchart showing a heating method calculation method for linear heating according to the first embodiment of the present invention. FIG. 2 is a conceptual diagram of a steel plate in the flowchart shown in FIG. 1, wherein (a) is a lattice model of a target shape, (b) is a planar shape of a lattice model formed using a finite element method, and (c). FIG. 4 is a diagram showing the calculated arrangement of heating lines.

  As shown in FIGS. 1 and 2, the heating method calculation method for linear heating according to the embodiment of the present invention creates a lattice model for creating a lattice model M for the finite element method indicating a target shape 1 desired to be created by heating. Using the creation step (Step 1) and the finite element method, the target shape 1 can be forcibly deformed to the planar shape 2 and then the planar shape 2 can be forcibly deformed to form the target shape 1 from the planar shape 2 The target inherent strain calculation step (Step 2) for calculating the target inherent strain P, which is a strain distribution, and the heating plan calculation for setting the heating scheme A including the arrangement of the heating wire 3 approximating the target inherent strain P, the heating rate, and the heating sequence. A heating method calculation method for linear heating having a step (Step 3), wherein the heating operation conditions for the interference pattern of the interference portion 4 where the heating wires 3 are dense and the standard value of deformation by the heating wires 3 A correction database creation step (Step 4) for measuring the amount of movement C to create a correction database B, and a heating line 3 to be corrected corresponding to the interference pattern are extracted from the heating plan A calculated in the heating plan calculation step (Step 3). Then, based on the correction database B, the fluctuation amount calculation step (Step 5) for calculating the fluctuation amount C of the heating wire 3 to be corrected, and the fluctuation amount C calculated by the fluctuation amount calculation step (Step 5) are added to the heating plan A. A correction deformation amount calculation step (Step 6) for calculating the correction deformation amount t, and a heating method recalculation step (Step 7) for recalculating the heating method A based on the correction deformation amount t to calculate the correction heating method A2. It is characterized by having.

  The lattice model creation step (Step 1) is a step of creating a lattice model M for the finite element method (for elastic FEM calculation). Specifically, as shown in FIGS. 1 and 2A, after a target shape 1 which is a curved surface shape to be created by bending is given, a lattice model M is created on the curved surface of the target shape 1 . The target shape 1 is, for example, a curved shape with a large bend that forms a bow-skin outer plate. Further, the bow / stern outer plate is often a thick plate having a thickness of 25 mm or more.

  The objective inherent strain calculation step (Step 2) is a step of obtaining a continuous strain distribution for deforming the planar shape 2 into the target shape 1. Specifically, as shown in FIG. 1 and FIG. 2 (b), the elastic large deformation FEM calculation is applied to force the target shape 1 into the planar shape 2 while keeping it freely movable in the in-plane direction. Further, the strain distribution is calculated when the deformation is forcibly deformed from the planar shape 2 to the target shape 1, and this strain distribution is set as the target inherent strain P.

  The heating plan calculation step (Step 3) is a step of calculating a heating plan A that can form the target shape 1 from the planar shape 2. Specifically, the arrangement of the heating wire 3 approximating the target inherent strain P and the heating rate when the heating source is run along the heating wire 3 are calculated. In addition, the construction order (heating order) of the plurality of heating wires 3 is selected according to empirical or statistical rules. Therefore, the heating method A is a heating condition including at least the arrangement of the heating wire 3 and the heating rate, and preferably including the heating sequence. In addition, the heating method A is provided with a continuous heating line (having a length straddling the plate width or plate length of the target steel plate) in the main curvature direction orthogonal to the two directions of the curved surface, and these are crossed in two directions. The heating rate (heat input condition) is selected using the heating line element (combination thereof) as a calculation unit.

  The calculation method of the heating method A from the lattice model creation step (Step 1) to the heating method calculation step (Step 3) is the same as the method described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2003-211230), for example. It is. However, the conventional calculation method of the heating method is based on the assumption that the sum of the plastic deformations of each heating line forms a shape. On the other hand, in the present invention, in the interference part 4 where the heating wires 3 are densely packed, the deformation when two or more heating wires 3 are approached is greatly different from the sum of the estimated deformations one by one. However, the variation was invented by obtaining the knowledge that the phenomenon that various modes are shown by the combination of heating conditions occurs. That is, with respect to the conventional heating method calculation method, the heating method A of the interference portion 4 of the heating wire 3 is corrected, a more accurate heating method (positive heating method Ar) is calculated, and the target is obtained from the planar shape 2. A curved surface shape closer to the shape 1 can be formed. Specifically, the present invention is characterized in that steps (Step 4 to Step 8) enclosed by a broken line in FIG. 1 are added.

  The correction database creation step (Step 4) is a step of creating the correction database B by measuring the variation amount C corresponding to the interference pattern of the interference portion 4 where the heating wires 3 are densely packed. Specifically, for each material and thickness of the metal plate to be bent, parameters are arranged so as to cover the interference pattern of the heating wire 3, and a heating method (the arrangement of the heating wire 3, the heating speed and For the combination of (heating order), a variation amount C from the standard value of the deformation to be created is measured to create a correction database B which is a nonlinear variation database. Here, the standard value means the plastic deformation amount of each heating wire 3 in the heating wire 3 other than the interference portion 4 (that is, the deformation amount when the deformation by the heating wire 3 does not affect each other). . Also, if the number of combined conditions of the heating method becomes enormous, experiments and nonlinear simulations (from heat source characteristics measurement tests, heat source characteristics and heating conditions to estimate the time distribution of temperature distribution, and simulation of time distribution of estimated temperature distribution) The correction database B may be created in combination with a thermoelastic-plastic simulation performed using the change data.

  Here, FIG. 3 is an explanatory diagram showing an interference pattern, in which (a) is parallel, (b) is superimposed, (c) is oblique, and (d) is orthogonal. As shown in FIG. 3, there are, for example, four types of interference patterns: parallel, superimposed, oblique, and orthogonal.

  The “parallel” interference pattern shown in FIG. 3A shows a state in which two heating wires 3 (for example, the first heating wire 31 and the second heating wire 32) are arranged at a predetermined arrangement interval g. means. In the figure, a case where three heating wires 3 (first heating wire 31, second heating wire 32, and third heating wire 33) are arranged in parallel is illustrated. Here, the predetermined arrangement interval g has an influence on the plastic deformation when heated by the heating method A along the first heating line 31 and the second heating line 32 (the sum of plastic deformation is not established). ) Means interval. Therefore, the arrangement interval g is generally a close value, but is a value that is appropriately changed depending on conditions such as the material, thickness, and heating temperature of the plate material to be bent. Further, when the arrangement interval g becomes narrower, the influence on each other becomes larger, and when the arrangement interval g becomes wider, the influence on each other becomes smaller.

  The “overlapping” interference pattern shown in FIG. 3B means a state in which two or more heating wires (for example, the first heating wire 31 and the second heating wire 32) overlap each other. In the figure, a case where three heating wires 3 (first heating wire 31, second heating wire 32, and third heating wire 33) are arranged in an “overlapping” manner is illustrated. Such “superimposition” is also a state in which the arrangement interval g is zero in the “parallel” interference pattern. In FIG. 3B, for convenience of explanation, the first heating line 31 to the third heating line 33 are illustrated with being distinguished by a gray gradation in a slightly shifted state.

  The “oblique” interference pattern shown in FIG. 3C is obtained when the crossing angle θ formed by two heating lines 3 (for example, the first heating line 31 and the second heating line 32) is a right angle (90 °). Means no state. In the figure, a case where three heating wires 3 (second heating wire 32, third heating wire 33, and fourth heating wire 34) are arranged in an “oblique” manner with respect to the first heating wire 31 is illustrated. ing. The state where the crossing angle θ is 0 ° or 180 ° is “superimposition”.

  The “orthogonal” interference pattern shown in FIG. 3D means a state in which two heating lines 3 (for example, the first heating line 31 and the second heating line 32) are orthogonal to each other. In the figure, a case where three heating wires 3 (second heating wire 32, third heating wire 33, and fourth heating wire 34) are arranged “perpendicular” with respect to the first heating wire 31 is illustrated. Yes. That is, the state where the crossing angle θ is 90 ° is “orthogonal”.

  Here, the concept of the influence of the “orthogonal” interference pattern on plastic deformation will be described with reference to FIG. 4A and 4B are conceptual explanatory diagrams of fluctuation amounts due to orthogonal heating, in which (a) is heating by the first heating wire, (b) is heating by the second heating wire, (c) is shrink deformation in the Y-axis direction, ( d) shows shrinkage deformation in the X-axis direction. Moreover, in FIG.4 (c) and (d), the shrinkage deformation | transformation in orthogonal heating is displayed with the continuous line, and the shrinkage deformation | transformation in single heating is displayed with the dashed-dotted line. The single heating means heating for each heating wire 3 other than the interference unit 4 (that is, heating when deformation by the heating wire 3 does not affect each other).

  Now, as shown in FIG. 4A, the first heating line 31 is applied in the X-axis direction on the XY plane, and as shown in FIG. 4B, the second heating line is applied in the Y-axis direction on the XY plane. The case where 32 is given is assumed. When such orthogonal heating is applied, as shown in FIG. 4C, in the case of independent heating, the value of shrinkage deformation (lateral contraction) δy in the Y-axis direction is constant, whereas in the case of orthogonal heating. In this case, the numerical value of contraction deformation (lateral contraction) δy in the Y-axis direction increases with the intersection indicated by a broken line as the center. In addition, as shown in FIG. 4D, the value of shrinkage deformation (lateral shrinkage) δx in the X-axis direction is constant in the case of single heating, whereas in the case of orthogonal heating, The numerical value of the contraction deformation (lateral contraction) δx decreases with the intersection shown by the broken line as the center. Such increase / decrease in shrinkage deformation (lateral contraction) is likely to occur particularly when the target metal plate is a thick plate (for example, a thickness of 25 mm or more) or when the target shape is a curved surface with a large bend.

  In this way, in the case of orthogonal heating, the shrinkage deformation (lateral shrinkage) at the intersecting portion is greatly different from that in the case of single heating. Therefore, the plastic deformation of each heating line in the conventional heating method calculation method is performed. The assumption that the sum of them forms a shape is no longer valid. Although not shown, this phenomenon can also occur in other interference patterns (parallel, overlap, intersection).

  Next, the relationship between the above-described interference pattern and correction database B parameters will be described. Here, Table 1 is a table showing the relationship between the interference pattern and the parameters of the correction database. In addition, an interference pattern (parallel, overlap, intersection, orthogonal) is displayed on the horizontal axis, and parameters (heating order, heating speed, heating surface, arrangement interval, number of overlaps, intersection angle) are displayed on the vertical axis. That is, the correction database B has, as parameters, the heating order, the heating speed, the heating surface, the arrangement interval, the number of overlapping times, or the intersection angle with respect to the interference pattern.

  The parameter of “heating order” is that self (the heating wire 3 to be corrected) is heated first (preceding heating) with the heating wire 3 that forms the interference pattern, or is heated later. (Subsequent heating). This parameter is based on the fact that the variation amount C changes depending on the later order of the heating sequence. In most cases, the variation amount C appears in the opposite direction depending on the later order of the heating sequence. Therefore, when the heating sequence parameter in the correction database B includes the first heating line 31 and the second heating line 32 that form an interference pattern (see FIG. 3), the heating order parameter of the first heating line 31 and the second heating line 32 is determined. The latter part of the heating sequence is included as a condition value.

  The parameter of the “heating rate” is based on the condition of the combination of the heating rate (self-rate) of self (correction target heating wire 3) and the heating rate (partner velocity) of the combination partner heating wire 3 constituting the interference pattern. It is a thing. This parameter is based on the fact that the amount of heat input varies depending on the moving speed of the heating source, and the variation amount C varies depending on the combination of the heating speed (self speed and counterpart speed). Therefore, when the heating rate parameter in the correction database B includes the first heating line 31 and the second heating line 32 that form the interference pattern (see FIG. 3), the heating rate and the second heating rate of the first heating line 31 are used. A combination with the heating rate of the wire 32 is included as a condition value.

  The parameter of the “heating surface” is such that the surface on which self (the heating wire 3 to be corrected) is applied and the surface on which the heating wire 3 to be combined constituting the interference pattern is applied are the same surface, or It is a condition that it is the opposite side. This parameter is based on the variation amount C changing depending on whether the heating surfaces are the same. Therefore, when the heating surface parameter in the correction database B includes the first heating line 31 and the second heating line 32 that form an interference pattern (see FIG. 3), the first heating line 31 and the second heating line 32 are Whether it exists in the same surface or the opposite surface is included as a condition value.

  The parameter of “arrangement interval” is the latest heating line 3 that is pre-heated from self when there are a plurality of heating lines 3 that are adjacent to the combination (composition target heating line 3) and the interference pattern. The distance (interval) is a condition. This parameter is based on the variation amount C changing depending on the arrangement interval. Therefore, the arrangement interval parameter in the correction database B includes, as a condition value, the distance from the nearest heating line 3 that is preheated when the plurality of heating lines 3 are formed by the interference pattern (see FIG. 3). .

  The parameter “number of superpositions” is based on the number of superpositions (the number of superpositions) of the self (correction target heating wire 3) and the heating wire 3 of the combination partner constituting the “superposition” interference pattern. It is. This parameter is based on the fact that the amount of variation C changes depending on whether the same heating position is heated only once, heated twice, or repeatedly heated many times. Therefore, the superposition number parameter in the correction database B is a case where the interference pattern is superposed, and includes the number of heating wires 3 to be superposed as a condition value. In actual application, for example, it is assumed that the variation amount C does not change depending on the number of times, and the variation amount C corresponding to the heating rate may be incremented and added for the number of times of superimposition.

  The parameter of “intersection angle” is based on how many times the intersection angle θ between self (the heating line 3 to be corrected) and the heating wire 3 of the mating partner that forms the “oblique” interference pattern. It is. This parameter is based on the fact that the fluctuation amount C changes depending on the magnitude of the intersection angle θ. Therefore, the crossing angle parameter in the correction database B is the case where the interference pattern is oblique and has the first heating line 31 and the second heating line 32 that form the interference pattern (see FIG. 3). An angle formed by one heating line 31 and the second heating line 32 is included as a condition value.

  Next, parameters of the correction database B will be described for each interference pattern with reference to FIG. 3 and Table 1. In addition, the parameter mentioned above is set to the line element unit which comprises the heating wire 3 which is a calculation unit of a heating plan, for example.

  In the “parallel” interference pattern shown in FIG. 3A, as shown in Table 1, the heating sequence, the heating speed, the heating surface, and the arrangement interval are used as parameters. For example, as shown in FIG. 3A, the first heating wire 31, the second heating wire 32, and the third heating wire 33 are arranged in “parallel” and heated in this order. When the second heating wire 32 is selected as the heating wire 3 to be corrected, the arrangement interval g with respect to the first heating wire 31 is used as data for the “arrangement interval” parameter.

  In the “superimposition” interference pattern shown in FIG. 3B, as shown in Table 1, the heating sequence, the heating speed, the heating surface, and the number of superpositions are used as parameters. For example, as shown in FIG. 3B, when the first heating line 31, the second heating line 32, and the third heating line 33 are “superposed”, the number of superpositions is three. In addition, in the parameter of “heating surface”, when the number of times of superimposition is three times or more, there are cases where the heating wire 3 of each number is the same surface and a case where it is the opposite surface. Use in combination.

  In the “oblique” interference pattern shown in FIG. 3C, as shown in Table 1, the heating sequence, the heating speed, the heating surface, the arrangement interval, and the crossing angle are used as parameters. For example, as shown in FIG. 3C, the second heating wire 32, the third heating wire 33, and the fourth heating wire 34 are “obliquely crossed” with respect to the first heating wire 31, and heating is performed in this order. Shall be. If the third heating wire 33 is selected as the heating wire 3 to be corrected, the arrangement interval with the second heating wire 32 is used as data for the “arrangement interval” parameter.

  In the “orthogonal” interference pattern shown in FIG. 3D, as shown in Table 1, the heating order, the heating speed, the heating surface, and the arrangement interval are used as parameters. For example, as shown in FIG. 3D, the second heating wire 32, the third heating wire 33, and the fourth heating wire 34 are “orthogonal” with respect to the first heating wire 31 and are heated in this order. Shall be. If the third heating wire 33 is selected as the heating wire 3 to be corrected, the arrangement interval with the second heating wire 32 is used as data for the “arrangement interval” parameter. For example, when the “arrangement interval” is narrow, the residual stress due to the previous oblique heating (oblique heating of the first heating line 31 and the second heating line 32) is released, and this oblique heating ( The variation amount C due to the oblique heating of the first heating line 31 and the third heating line 33 tends to be small.

  The above-described interference patterns and parameters are merely examples, and special interference patterns may be added when more detailed corrections or special fluctuations such as singular points are taken into account. Types such as plate thickness and heating temperature may be added. Of course, if simplification is desired, an arbitrary parameter may be deleted or ignored.

  Here, FIG. 5 is a diagram showing an example of a correction database table in orthogonal heating, in which (a) is a table of fluctuations in lateral contraction with respect to the first heating line of the same surface heating, and (b) is a first table of the same surface heating. Transverse shrinkage variation table for two heating lines, (c) is a transverse shrinkage variation table for the first heating line of opposite surface heating, and (d) is a transverse shrinkage variation table for the second heating line of opposite surface heating. .

  In the tables shown in FIGS. 5A to 5D, fluctuation data (fluctuation amount C) of the lateral contraction with a plate thickness of 20 mm, the heating speed of the preheating (V11 to V110) on the vertical axis, and the subsequent on the horizontal axis. The heating rate (V21 to V210) of heating is taken, and the fluctuation amount C (mm) which is fluctuation data in each combination is shown. The heating speed (V11 to V110 and V21 to V210) may be set to, for example, 10 levels from 50 mm to 5000 mm per minute. Moreover, in the 1st heating wire 31 and the 2nd heating wire 32 which form an "orthogonal" interference pattern (refer FIG. 3), the 1st heating wire 31 is set as preheating and the 2nd heating wire 32 is set as subsequent heating.

  The variation table shown in FIG. 5A is a variation table of lateral contraction of the first heating wire 31 (preceding heating) when the first heating wire 31 and the second heating wire 32 are coplanar heating. . Further, the variation table shown in FIG. 5B is a variation table of the lateral contraction of the second heating line 32 (subsequent heating) when the first heating line 31 and the second heating line 32 are the same surface heating. It is. Note that the data of the fluctuation amount C is displayed with symbols in the form of A1121 to A110210 in the fluctuation table shown in FIG. 5A and B1121 to B110210 in the fluctuation table shown in FIG. 5B. However, the measured value is actually input.

  The variation table shown in FIG. 5C is a variation table of lateral contraction of the first heating line 31 (preceding heating) when the first heating line 31 and the second heating line 32 are opposite surface heating. . The variation table shown in FIG. 5D is a variation table of the lateral contraction of the second heating line 32 (subsequent heating) when the first heating line 31 and the second heating line 32 are opposite surface heating. It is. Note that the data of the fluctuation amount C is represented by symbols in the form of symbols such as C1121 to C110210 in the fluctuation table shown in FIG. 5C and D1121 to D110210 in the fluctuation table shown in FIG. However, the measured value is actually input.

  Thus, the variation table in the orthogonal heating is, for example, whether the heating wire 3 is the preceding heating, the subsequent heating, the same surface heating, or the opposite surface heating with respect to the combination partner. There are four tables for the combination. A similar combination table is formed for each deformation component (lateral contraction, lateral bending, longitudinal contraction, vertical bending). Other interference patterns (parallel, superimposition, oblique) are also configured with similar tables. Note that the heating rate levels shown in the table of FIG. 5 may be filled by interpolation by calculation.

  The present invention calculates the fluctuation amount C of the interference part 4 of the heating wire 3 for the heating method A calculated by the conventional method using the correction database B described above, and the following fluctuation amount calculation step ( From Step 5) to the heating plan recalculation step (Step 7), a more accurate heating plan (positive heating plan Ar) is calculated. In addition, although the correction | amendment database creation process mentioned above was displayed as Step4 for convenience of explanation, correction database B is created beforehand before using the heating method calculation method of the present invention.

  The fluctuation amount calculation step (Step 5) is a step of calculating the fluctuation amount C from the correction database B for the heating wire 3 to be corrected. Specifically, for the heating wire 3 arranged according to the heating method A, the relationship with the heating wire 3 other than the self is examined, and when they correspond to a predetermined interference pattern (parallel, overlap, oblique, orthogonal) Searches the correction database B by adding information on the mutual heating rate and heating sequence (following), and obtains the variation C. When obtaining the fluctuation amount C, the fluctuation amount C set by the table may be used as it is, or the fluctuation amount C may be calculated by interpolating or adjusting the data in the table. This series of processing is performed by a computer program installed in a computer that calculates the heating plan A, a computer that is connected to the computer that calculates the heating plan A via a network, or a computer that is separate and independent from the computer that calculates the heating plan A. Also good.

  The correction deformation amount calculating step (Step 6) is a step of adding the calculated fluctuation amount C to the heating plan A. Specifically, when heating is performed based on the heating method A, the variation amount C is added to the deformation amount applied to the planar shape 2 to calculate the corrected deformation amount t. The corrected deformation amount t corresponds to a predicted deformation amount after receiving interference between the heating wires 3. In this way, by considering the fluctuation amount C due to the interference of the heating wire 3, it is possible to take into account the non-linear effect in the framework of the conventional linear addition system.

  The heating plan recalculation step (Step 7) is a step of correcting the heating plan A by calculating the corrected heating plan A2 based on the corrected deformation amount t. For example, in the heating plan calculation step (Step 3), the calculation of the heating plan A is performed by taking up the orthogonal line elements constituting the heating wire lattice so that the deformation amount becomes an integral value of the target intrinsic strain P of the corresponding part. Calculation to select the condition. At this time, the correction deformation amount t calculated in the correction deformation amount calculation step (Step 6) is the constant C accompanied by the line element of the corresponding part, with the variation amount C accompanying the heating wire interference obtained in the variation amount calculation step (Step 5). It is assumed that the numerical value is added by the amount of the captured and fluctuation amount C. In the heating plan recalculation step (Step 7), the heating plan is calculated again with the target inherent strain P as the target, and the corrected heating plan A2 is calculated. That is, the heating plan recalculation step (Step 7) in the first embodiment is a step including recalculating the heating plan A based on the corrected deformation amount t (directly, the variation amount C).

  In addition, as shown in FIG. 1, after the heating method recalculation step (Step 7), a recalculation number confirmation step (Step 8) for confirming whether or not the recalculation of the heating method A has been performed the required number (N times). It may be incorporated. When the recalculation of the heating method A is performed, the interference effect of the heating wire 3 corresponding to the heating rate of the correction heating method A2 is different from the interference effect of the heating wire 3 in the heating method A before correction. Therefore, similarly to the heating method A, it is preferable to repeat the fluctuation amount calculation step (Step 5) and the correction deformation amount calculation step (Step 6) for the correction heating method A2. Therefore, when the recalculation of the heating method A is not performed the required number of times (N times), the process returns to the fluctuation amount calculation step (Step 5), and the steps of the fluctuation amount calculation step (Step 5) to the heating method recalculation step (Step 7). To repeat.

  Here, the required number (N times) of N may be a positive integer that can be arbitrarily set, and may be N = 1. When N = 1 is fixed, the recalculation count confirmation step (Step 8) may be substantially omitted. Moreover, when fixing by N = 2, instead of the recalculation count confirmation step (Step 8), the fluctuation amount calculation step (Step 5), the correction deformation amount calculation step (Step 6), and the heating plan recalculation step (Step 7) are performed. It may be performed again.

  Then, the corrected heating plan An obtained by performing recalculation of the heating plan A a required number of times (N times) is adopted as the positive corrected heating plan Ar, and the process proceeds to the next step. Since the fluctuation amount due to the interference is smaller than the fluctuation amount C of the first heating method A, the recalculation of the heating method A is repeated a small number of times (for example, about once or several times. However, it is limited to this. It is not a thing.) It can converge and endure practical use.

  Further, since the variation amount C is smaller than the plastic deformation amount due to heating, the variation amount C is further smaller than the plastic deformation amount. Therefore, as a simplified concept, it is possible to obtain a positive heating method Ar that can withstand practical use even if the variation amount C obtained first is ignored without changing the variation amount C. Specifically, in the repetition process of the heating plan calculation step (Step 3) to the heating plan recalculation step (Step 7), the fluctuation amount C is not calculated for each repetition, but is calculated by the first fluctuation amount calculation step (Step 5). The recalculation of the heating method A may be repeated N times using the obtained variation amount C.

  After the positive heating scheme Ar is set, heating is performed along the following heating construction flow. In the heating construction flow, an output shape calculation step (Step 9) for calculating an output shape which is a curved surface shape based on the generated inherent strain Q, and whether or not a difference e between the output shape and the target shape 1 is a reference value β or less. An output shape confirmation step (Step 10) to be confirmed, a corrected target shape calculation step (Step 11) for calculating a corrected target shape obtained by adding the difference e to the target shape 1 when the difference e is equal to or larger than the reference value β, and the difference e A heating construction step (Step 12) for constructing heating based on the heating scheme Ar when the reference value β is equal to or less than the reference value β.

  In the output shape calculation step (Step 9), the generated inherent strain Q approaching the target inherent strain P is input to the elastic FEM program, free deformation calculation is performed, and the curved surface shape is calculated.

  In the output shape confirmation step (Step 10), the output shape and the target shape 1 are compared. Specifically, the determination is made based on whether or not the difference e is 10 to 100% or less with respect to the target shape 1. This difference e is caused by a difference in shape remaining because a residual stress is generated in the non-heated portion around the discrete strain of the heating wire 3. Here, the reference value β is set to a plate thickness ratio of 10 to 100% because there is a difference in required deflection accuracy depending on the target plate. For example, a large plate having a width of 3 m, a length of 15 m, and a thickness of about 20 mm is used. A difference of about a plate thickness is allowed, and in a thick plate of about 30 to 50 mm, the plate size is small (for example, about 2 m in width and about 3 m in length), and the rigidity of the curved surface is high. This is because it is only allowed.

  In the corrected target shape calculating step (Step 11), a corrected target shape is calculated as a new target shape 1 obtained by adding a shape difference (difference e) to the target shape 1 in the reverse direction. When the corrected target shape is calculated, a new target shape 1 is given, and therefore the process of calculating the positive heating plan Ar from the lattice model creating process (Step 2) is repeated again. Since this heating method calculation step is as described above, the description thereof is omitted here.

  In the heating construction step (Step 12), the steel plate is heated based on the heating plan Ar that has passed the output shape confirmation step (Step 10).

  The above-described heating construction flow is the same flow as the case of performing the heating construction based on the heating method calculated by the conventional heating method calculation method, and is not limited to the illustrated one, and other conventional methods Can also be applied.

  According to the heating method calculation method for linear heating according to the present invention described above, attention is paid to the interference pattern of the heating wire 3, a correction database B corresponding to this interference pattern is created, and the heating method is calculated using the correction database B. By correcting A, even when the target metal plate is a thick plate or when the heating wire is dense, the deformation can be accurately predicted, and the target shape 1 is based on the prediction. It is possible to calculate an excellent heating scheme Ar capable of forming

  Therefore, real-time calculation is difficult and expensive using a large-scale calculation environment for the automation of advanced bending processes such as the stern structure that could not be processed with the current automatic bending system despite high demand. Without using a non-linear simulation, the present automatic bending system, which is a linear addition system, can be easily realized by simply expanding it.

  Then, the heating method calculation method of the linear heating which concerns on other embodiment of this invention is demonstrated. Here, FIG. 6 is a flowchart showing a heating method calculation method for linear heating according to the second embodiment of the present invention. In addition, about the same part as 1st embodiment mentioned above, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  The second embodiment shown in FIG. 6 includes a generated inherent strain confirmation step (Step 13) between the heating method recalculation step (Step 7) and the recalculation count confirmation step (Step 8) in the first embodiment shown in FIG. ). In the generated inherent strain confirmation step (Step 13), it is determined whether or not the difference d obtained by comparing the strain distribution (generated inherent strain Q) formed on the basis of the corrected deformation amount t with the target inherent strain P is equal to or less than the reference value α. It is a process to confirm. If the difference d is less than or equal to the reference value α, the recalculation of the heating plan A is terminated, and the process proceeds to the next output shape calculation step (Step 9). If the difference d is not less than or equal to the reference value α, the process proceeds to the recalculation count confirmation step (Step 8). By incorporating the generation inherent strain confirmation step (Step 13), the heating plan A can be corrected to a level at which it can proceed to the next step even if the recalculation of the heating plan A is not performed the required number of times (N times). In addition, it is possible to skip the useless recalculation of the heating method A and proceed to the next process, thereby improving the work efficiency.

  Here, the generated inherent strain Q is a discrete strain distribution including a deformation distribution created based on the corrected deformation amount t. If the generated inherent strain Q is sufficiently close to the target inherent strain P, the curved surface obtained by executing this heating method An is close to the target shape 1. Whether or not the generated inherent strain Q is sufficiently close to the target inherent strain P is determined by the reference value α as described above. The reference value α is set such that, for example, the difference d between the generated inherent strain Q and the target inherent strain P is 5 to 10% of the target inherent strain P. The difference d is calculated and compared for each strain component. If the difference d is within about 5 to 10% (reference value α), the difference d is heated (Step 12) by the processing from the output shape calculation step (Step 9) to the corrected target shape calculation step (Step 11). ) Can be converged to a practical level that does not affect. In addition, the numerical value of the reference value α described above is merely an example, and is not limited thereto. For example, the setting may be changed based on an experience value, or a test target or the like may be repeated in advance. You may calculate and set the optimal numerical value for a steel plate.

  In calculating the difference d, the target inherent strain P output by the FEM calculation has a smooth and continuous distribution, while the generated inherent strain Q of the heating method An picks up the discrete deformation of the slice, The strain Q is smoothed and compared with the target inherent strain P. The generated inherent strain Q is smoothed by, for example, averaging the generated inherent strain picked up in units of FEM elements between adjacent FEM elements.

  Also by the heating method calculation method for linear heating according to the second embodiment described above, the heating method A is corrected using the correction database B, similarly to the heating method calculation method for linear heating according to the first embodiment. Can produce the same effect. In the second embodiment, the variation amount C may be calculated for each repetition and the heating method may be recalculated, or the heating method may be recalculated with the initial value fixed.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention, such as being applicable to bending of various metal plates other than the outer plate bending of shipbuilding. Of course.

DESCRIPTION OF SYMBOLS 1 Target shape 2 Planar shape 3 Heating line 4 Interference part 31 1st heating line 32 2nd heating line

Claims (13)

A lattice model creation step for creating a lattice model for a finite element method indicating a target shape to be created by heating, and forcibly deforming the target shape into a planar shape using the finite element method, the planar shape is then converted into the target shape. A target inherent strain calculating step for calculating a target inherent strain, which is a strain distribution capable of forming the target shape from the planar shape, and a heating line arrangement, a heating rate and a heating sequence approximating the target inherent strain. A heating plan calculation step for setting a heating plan including: a heating plan calculation method for linear heating,
A correction database creation step of measuring a heating construction condition for the interference pattern of the interference portion where the heating lines are dense and a variation amount from a standard value of deformation by the heating line to create a correction database,
Fluctuation amount calculation for extracting a heating line to be corrected corresponding to the interference pattern from the heating plan calculated in the heating plan calculation step, and calculating the fluctuation amount of the heating line to be corrected based on the correction database Process,
A correction deformation amount calculating step of calculating the correction deformation amount by adding the fluctuation amount calculated in the fluctuation amount calculation step to the heating method;
A heating plan recalculation step of recalculating the heating plan based on the corrected deformation amount to calculate a corrected heating plan;
A heating method calculation method for linear heating, comprising:   The heating method calculation method for linear heating according to claim 1, wherein the interference pattern is parallel, superimposed, oblique, or orthogonal.   The heating for linear heating according to claim 2, wherein the correction database has a heating sequence, a heating speed, a heating surface, an arrangement interval, the number of overlapping times, or an intersection angle as parameters for the interference pattern. Method calculation method.   When the heating sequence parameter in the correction database includes the first heating line and the second heating line that form the interference pattern, the heating sequence parameter of the first heating line and the second heating line is a condition value. The heating method calculation method for linear heating according to claim 3, comprising:   When the heating rate parameter in the correction database includes a first heating line and a second heating line that form the interference pattern, a combination of a heating rate of the first heating line and a heating rate of the second heating line The heating method calculation method for linear heating according to claim 3, further comprising:   When the heating surface parameter in the correction database includes the first heating line and the second heating line that form the interference pattern, the first heating line and the second heating line exist on the same surface or the opposite surface. The heating method calculation method for linear heating according to claim 3, further comprising: whether or not as a condition value.   The arrangement interval parameter in the correction database includes, as a condition value, a distance from the nearest heating line that is pre-heated when the interference pattern has a plurality of heating lines formed by the interference pattern. The heating method calculation method of the linear heating of description.   The heating method for linear heating according to claim 3, wherein the superposition number parameter in the correction database includes the number of heating lines to be superposed as a condition value when the interference pattern is superposed. Calculation method.   The crossing angle parameter in the correction database is the case where the interference pattern is oblique and includes the first heating line and the second heating line that form the interference pattern, and the first heating line and the second heating line. The method for calculating a heating method for linear heating according to claim 3, wherein an angle formed by the two heating lines is included as a condition value.   The heating method calculation method for linear heating according to claim 1, wherein the correction database includes a table for each strain component of lateral contraction, lateral bending deformation, longitudinal contraction, or vertical bending deformation.   The heating method recalculation step is based on the difference between the generated inherent strain and the target inherent strain which is a strain distribution formed based on the corrected deformation amount until the heating method is recalculated as many times as necessary. The heating method calculation method for linear heating according to claim 1, comprising repeating recalculation of the heating method until the value becomes equal to or less than a value.   12. The linear heating according to claim 11, wherein the reference value is such that a difference between the generated inherent strain and the target inherent strain is 5 to 10% of the target inherent strain. Heating plan calculation method.   The heating method calculation method for linear heating according to claim 1, wherein the correction heating method is calculated by recalculating at least the heating rate.