JP5241991B2 - Deformation estimation method, program, and recording medium - Google Patents

Description

  The present invention relates to a method for estimating deformation caused by thermal processing, particularly deformation caused by welding.

  Deformation caused by thermal processing such as welding not only affects the appearance and appearance of the product, but also affects the assembly and welding processes when manufacturing the product, and also affects the function and performance of the product. Controlling and suppressing deformation is an industrially important issue.

The purpose of estimating the deformation is to keep the processed member or structure within the required dimensional accuracy. For example, instead of focusing on estimating weld deformation, which is a deformation caused by welding, by estimating weld deformation,
(1) Changing the welding procedure to reduce the amount of deformation caused by welding (2) Suppressing deformation using a restraining jig that is a jig for restraining deformation of the member (3) Before welding (4) It is possible to change the dimension or shape of the member in consideration of the welding deformation before welding, after welding. The purpose of this is to reduce or eliminate the strain removal work and to produce a structure with the required dimensional accuracy.

  Methods for estimating welding deformation are broadly divided into methods based on thermal elasto-plastic analysis, which simulates welding phenomena as they are, and methods that are approximately obtained by elastic analysis using concepts such as intrinsic strain, intrinsic deformation, or intrinsic stress. The Recent breakthroughs in computing power of computers have enabled thermoelastic-plastic analysis using the finite element method. However, the welding phenomenon is a phenomenon during cooling from the high temperature region where the metal is melted to room temperature, and the analysis of this melting phenomenon must consider the temperature dependence of various physical properties of the welded structure. Non-linear analysis. In particular, it is necessary to consider that the yield surface becomes very small at high temperatures and that the plastic strain is canceled when it is melted. It is no exaggeration to say that this is virtually impossible.

  Therefore, the analysis method using the concept of intrinsic strain is the only welding deformation estimation method that can be used industrially. Concepts such as intrinsic strain are based on the assumption that the plastic strain generated in the vicinity of the weld due to welding causes the welding deformation, that is, assuming that the part was cut out. Although it is in an elastic state, it is considered that the site where plastic strain is generated has a shape that has a gap or overlaps with its surroundings. Intrinsic strain, intrinsic deformation, or intrinsic stress, along the weld line, has uniform strain along the weld line, that is, inherent strain, assuming that the magnitude is uniform along the weld line, respectively. It is assumed that there is uniform displacement, that is, natural displacement, or that uniform external force, that is, natural stress, acts on the weld line.

  The concept of intrinsic strain is based on basic joint types such as butt welding or fillet welding based on weld deformation data obtained by performing bead welding on peripheral free members, that is, unconstrained members. The deformation prediction formula or inherent strain data for is stored in advance. Next, when performing elastic analysis by the finite element method, the inherent strain of the type that corresponds to the actual joint is applied to the finite element model of the actual structure that is the structure to be applied, and the deformation is estimated Is. Therefore, the analysis basically assumes free deformation, that is, welding deformation when welding is performed in an unconstrained state.

  FIG. 11 is a diagram showing a flow in estimating welding deformation using a conventional inherent strain. In step S21, the target structure, which is the structure of the structure to be welded, the joint form indicating the joining form of the members, the material of the member, and the plate thickness of the member are designated. In step S22, a welding method and welding conditions such as a welding heat input Q indicating the amount of heat applied during welding are designated. In step S23, the plate thickness h, the welding length L, and the material specified in step S21, and the welding method specified in step S22, based on the information in the inherent strain database that stores information on the inherent strain obtained in the experiment. The inherent strain determined by the welding heat input Q is required. In this inherent strain database, information indicating a relationship between a parameter for determining the inherent strain and an inherent strain obtained from the parameter is stored. Parameters for determining the inherent strain include welding heat input Q, plate thickness h, welding length L, and material.

  In step S24, elastic finite element analysis is performed in which the inherent strain obtained in step S23 is applied to the weld and elastic analysis is performed using a finite element method (FEM). Thus, in step S25, welding deformation of the welded structure is estimated. The welding deformation in this case is a free deformation, that is, a welding deformation caused by welding in an unconstrained state.

  When the case where the restraining jig is used is modeled and the elastic finite element analysis shown in FIG. 11 is performed, the deformation under the restraint can be obtained approximately. However, when assembling the members into larger blocks, the welded member must be released from the restraining jig, and the amount of deformation when released from the jig cannot be estimated.

  As a first conventional technique for estimating deformation using intrinsic strain and intrinsic deformation, a welded structure is a collection of welded joints of basic shapes, and the intrinsic strain and intrinsic deformation measured or calculated for each welded joint are measured. There is a residual stress and deformation prediction method for predicting the residual stress and deformation of the entire welded structure by giving it to the structure at that time in the welding order (see, for example, Patent Document 1).

  As a second conventional technique for estimating residual stress using intrinsic strain, a general-purpose analysis code that has a thermal stress analysis function for analyzing thermal stress and calculates stress generated in a structure by the finite element method is used. There is a residual stress prediction method. This method calculates the residual stress distribution by replacing the temperature data, which is a parameter necessary for the calculation of the general-purpose analysis code, and the physical property value related to the temperature data with the data of the inherent strain at the position corresponding to the node. (For example, refer to Patent Document 2).

  As a third conventional technique for estimating welding deformation, first, in order to apply the finite element method, based on CAD data, the members constituting the structure are divided into meshes having elements and nodes, and member information, welding Creates line information and welding condition information, and assigns nodes necessary to apply multipoint constraints. Next, when the weld line is specified, the amount of deformation due to welding at each element and each node in contact with the weld line is obtained. Set the load boundary condition based on the obtained deformation amount, the load due to its own weight, and the forced displacement load that is the load to correct the deviation due to actual measurement, and execute the analysis by the finite element method under the set load boundary condition. There is a welding deformation estimation method for estimating welding deformation. It is possible to reduce the manual input work required for estimating the welding deformation and to take into account the influence of the forced displacement load (for example, see Patent Document 3).

  When analyzing according to the welding procedure, since assembly is performed using welded members, if large deformation analysis that can consider that the initial position before welding is changed and that the rigidity is changed is performed. (1) changing the welding procedure described above to reduce the amount of deformation caused by welding, (3) canceling the welding deformation by giving a displacement or distortion in the opposite direction to the welding deformation before welding, and (4) It is possible to change the size or shape of the member in consideration of welding deformation before welding. Regarding (2) restraining deformation using a restraining jig that is a jig for restraining deformation of a member as described above, the case where the influence of restraint can be considered and the case where it cannot be considered There is. For example, when restraining welding deformation by restraint by pre-welding to members that make up the structure, such as tack welding, the state is maintained even after welding, so a structural model can be constructed. The deformation can be estimated by elastic analysis using the finite element method.

JP-A-6-180271 JP 2003-121273 A JP 2003-80393 A

  However, when manufacturing a large structure, after pressing and welding the member with a restraining jig, releasing the welded structure from the restraining jig and welding with another member to make a larger structure Is generally adopted. In this case, when the welded structure is released from the restraining jig, a strain that can be called a springback occurs, but this cannot be evaluated by a conventional analysis method. In the case of the conventional analysis method, the inherent strain given to the member for analysis is the value at the time of free deformation, and therefore the amount of deformation when the restraint jig is not used, and when the restraint jig is used The amount of deformation cannot be evaluated. In order to evaluate when a restraining jig is used, it is necessary to grasp the inherent strain under restraint by the restraining jig.

  That is, the above-described conventional technology can estimate free deformation, that is, welding deformation when welding is performed in an unconstrained state, but the inherent strain that is a condition given to the member when performing estimation is Because it is at the time of free deformation, it cannot be estimated about the welding deformation when the restraint jig is released after welding under restraint, that is, with the welded joint restrained using a jig or the like There are challenges.

  An object of the present invention is to provide a deformation estimation method, a program, and a recording medium capable of estimating welding deformation under constraint.

The present invention shows a target structure that is a structure of a member to be welded, a joint type that indicates a joining type of the member, a plate thickness h of the member, a welding length L that is a length to be welded, a welding method, and an amount of heat applied during welding. A first step of specifying the welding heat input Q ₀ and the material of the member to be welded;
Based on the inherent strain database that stores the value of the inherent strain obtained in the experiment, the longitudinal shrinkage inherent to the plate thickness h, joint type, weld length L, welding method, welding heat input Q ₀ and material specified in the first step. A second step of obtaining a strain g _x , a transverse contraction inherent strain g _y and a longitudinal bending angle deformation inherent strain θ _x ;
Object structure specified in the first step, based on the joint type and thickness, a third for calculating the by elastic analysis, the joint of each part by the bending moment M given uniformly to the weld line bending degree of restraint K _B Process,
Based on the information stored in the inherent strain database, the thickness h, joint type, weld length L, welding method, welding heat input Q ₀ and material specified in the first step, and the bending calculated in the third step A fourth step of obtaining a lateral bending angle deformation inherent strain θ _v under the constraint by the constraint degree K _B ;
The longitudinal shrinkage intrinsic strain g _x , the transverse shrinkage intrinsic strain g _y obtained in the second step , the longitudinal bend angular deformation intrinsic strain θ _x and the transverse bend angular deformation intrinsic strain θ _v obtained in the fourth step are applied as external forces to the weld. And a fifth step of determining a deformation amount of the welded structure by elastic analysis in a state where the restraining jig is released .

According to the present invention, the information indicating the relationship between the degree of bending constraint and the inherent strain is stored in the database. Therefore, if the degree of bending constraint for the actual structure to be estimated is given , the inherent strain , that is, the longitudinal strain is obtained from the database information. The shrinkage inherent strain g _x , the transverse shrinkage intrinsic strain g _y and the longitudinal bending angle deformation intrinsic strain θ _x can be specified, and the welding deformation under constraint can be estimated .

  The present invention is also a program for causing a computer to execute the deformation estimation method.

  According to the present invention, it is possible to provide a program for causing a computer to execute the deformation estimation method.

The present invention is also a computer-readable recording medium on which the program is recorded.
According to the present invention, it can be provided as a computer-readable recording medium in which a program for causing a computer to execute the deformation estimation method is recorded.

  According to the present invention, by estimating the deformation, the deformation can be controlled and suppressed, and the assembly man-hours and welding man-hours can be minimized by eliminating the groove gap and misunderstanding when assembling the block. It is possible to guarantee performance by eliminating the deformation correction work and providing a product with the required dimensional accuracy.

  FIG. 1 is a diagram for explaining types of welding deformation. FIG. 1A is a diagram for explaining the lateral contraction, and shows a case of a butt joint in which the members 100 a and 100 b are joined by a weld line 101. The lateral contraction is contraction in the direction perpendicular to the weld line 101. In this case, the lateral contraction length of each member 100a, 100b is reduced by S / 2. FIG. 1B is a diagram for explaining the vertical contraction. In this case as well, the members 100 a and 100 b are joined by the welding line 101. The longitudinal shrinkage is shrinkage in the direction of the weld line 101, and the longitudinal shrinkage length is reduced by ΔL / 2 at both ends. 1 (c) and 1 (d) are diagrams for explaining lateral bending deformation (hereinafter also referred to as lateral bending angle deformation). The lateral bending angle deformation is a deformation caused by a difference in lateral shrinkage within the plate thickness. is there. FIG. 1 (c) shows the lateral bending angle deformation in the case of the butt joint of the members 100a and 100b, and FIG. 1 (d) shows the lateral bending angle deformation in the case of the fillet joint of the members 102 and 103. . In any of the joint types shown in FIGS. 1C and 1D, the value of the lateral bending angle deformation is θ. FIG. 1E is a diagram for explaining the vertical bending deformation, and shows the vertical bending deformation (hereinafter, also referred to as vertical bending angle deformation) in the case of a fillet joint between the members 102 and 103. Longitudinal bending deformation is bending deformation that occurs because the weld line is different from the neutral axis of the cross section.

  These welding deformations are roughly classified into lateral shrinkage and longitudinal shrinkage, which are in-plane deformations, and lateral bending angle deformations and vertical bending angle deformations, which are out-of-plane deformations. Since the vertical bending deformation caused by the lateral shrinkage, the vertical shrinkage, and the vertical shrinkage is caused by a large shrinkage force, the deformation cannot be suppressed even when restrained using a jig in a large structure. Lateral bending angle deformation occurs due to the temperature distribution in the plate thickness direction when the weld becomes high temperature, and therefore it is possible to reduce deformation by using a restraining jig for restraining deformation. . That is, the welding deformation can be estimated on the assumption that only the inherent strain corresponding to the lateral bending angle deformation depends on the constraint condition for constraining the member to be welded.

The types of intrinsic strain include longitudinal shrinkage intrinsic strain g _x , transverse shrinkage intrinsic strain g _y , longitudinal bending angle deformation intrinsic strain θ _x , and transverse bending angle deformation intrinsic strain θ _v , respectively. It is the inherent strain of deformation and longitudinal corner deformation. These intrinsic strains are obtained by the respective functions shown in Table 1. These functions will be described later.

  FIG. 2 is a view for explaining a restraining jig used for suppressing deformation due to welding. As described above, the lateral bending angle deformation can be reduced by using a restraining jig for restraining the deformation, and FIGS. 2A to 2G show examples of the jig for that purpose. It is shown. FIGS. 2A to 2D are restraining jigs used to suppress lateral bending angle deformation in the case of a butt joint, and FIG. 2A shows the members 110a and 110b as strong backs 111, that is, The state which restrained with the welding jig | tool 111 which mechanically temporarily joins members is shown.

  FIG. 2 (b) shows a strong back 114 for a thin plate for restraining the lateral bending angle deformation when the thin plates 112a and 112b are joined together by a welding line 113. The strong back 114 is respectively attached to the thin plates 112a and 112b. It is temporarily attached like 115a and 115b. FIG. 2 (c) shows the thick plate strongbacks 118 and 119 for restraining the lateral bending angle deformation when the thick plates 116a and 116b are joined together by the weld line 117. 119 is temporarily attached like 120 and 121. The strong back 119 is for reinforcing the strong back 118. FIG. 2D shows a jig 124 that restrains the end of the member to prevent the angular deformation in order to constrain the lateral bending angle deformation and the vertical bending angle deformation when the members 122a and 122b are joined by the welding line 123. Is shown.

  FIGS. 2 (e) and 2 (f) are restraining jigs used for suppressing lateral bending angle deformation in the case of a fillet joint, and FIG. 2 (e) shows fillet welding of members 130 and 131. FIG. A strong back 132, sometimes used, is shown. FIG. 2 (f) shows jigs 142a and 142b that restrain deformation by interfering with each other when manufacturing H steels 140a to 140c. The restraining jigs 141a and 141b are the same kind of restraining jigs as in FIG.

  FIG. 2G is a restraining jig in the case of a boiler header, in which a large number of pipes for heat exchange of small-diameter pipes 152a to 152i and 153a to 153i are welded to two mother pipes 150 and 151, respectively. In addition, an example of a jig for restraining deformation by mutual interference by the restraining jigs 154a, 154b, and 155 is shown.

If the influence of the restraining jig on the lateral bending deformation can be taken into account, the welding deformation can be estimated even when welding is performed when the deformation is suppressed by the restraining jig. The degree of bending restraint used as a parameter for estimating restraint stress generated during welding is used as a parameter representing the restraint state of lateral bending angle deformation. This bending restraint degree is defined by the magnitude of the bending moment required to cause deformation of the groove angle at the groove position by a unit angle, for example, 1 radian. In the case of welding, the force that causes lateral bending angle deformation is almost unambiguous as a function form G ′ (Q, h, L, material) depending on the joint type, welding heat input Q, plate thickness h, weld length L, and material. Is determined. Therefore, the actual lateral bending angle deformation upon releasing the constraint, the bending degree of restraint K _B the function form G including (Q, h, K B, _L, material) can be written in.

  The inherent strain under constraint can be obtained experimentally, or can be calculated by repeating detailed thermoelastic-plastic analysis. As for the influence of restraint, it is possible to estimate welding deformation with industrially sufficient accuracy if only lateral bending angle deformation is considered as a first approximation.

FIG. 3 is a diagram illustrating a flow when welding deformation is estimated by a deformation estimation method using a bending constraint degree according to an embodiment of the present invention. In step S1, a target structure, which is a structure of a member to be welded, a joint type indicating a member joining type, and a plate thickness h of the member are designated. In step S2, a plate thickness h, a joint type, and a welding length L that is a length for welding are designated. In step S3, a welding method, welding conditions such as welding heat input Q ₀ which indicates the amount of heat applied to the welding, and material of the member for welding is specified.

In step S4, the plate thickness h, joint type and weld length L specified in step S2 and the welding method and welding specified in step S3 based on the inherent strain database storing the inherent strain values obtained in the experiment. The inherent strain determined by the heat input Q ₀ and the material, specifically, the longitudinal shrinkage intrinsic strain g _x , the transverse shrinkage intrinsic strain g _y , and the longitudinal bending angle deformation intrinsic strain θ _x are obtained.

In step S5, not only a welded structure to be welded but also a restraint jig is modeled, and based on the target structure, joint type, and plate thickness specified in step S1, a finite element method (FEM: Finite Element Method) is obtained. Elastic finite element analysis is performed to perform elastic analysis using In this case, in step S6, the bending moment M given uniformly to the weld line, by dividing its bending angular distortion amount which is deformed by the moment theta, joint bending degree of restraint K _B of each part is calculated .

In step S7, the value of the inherent strain under constraint obtained in the experiment is stored in the above-described inherent strain database, and the plate thickness h designated in step S2 is based on the information stored in the inherent strain database. a joint type and weld length L, the welding heat input Q ₀ and material as specified welding method in step S3, and bending calculated depends degree of restraint K _B in step S6, the strain-specific under restraint, specifically , The lateral bending angle deformation inherent strain θ _v is obtained.

In step S8, the state where the restraining jig is released is modeled, and an analysis using an elastic finite element analysis or an analysis technique is performed. At this time, in step S9, the longitudinal contraction inherent strain g _x , the transverse contraction inherent strain g _y obtained in step S4, the longitudinal bending angle deformation inherent strain θ _x , and the lateral bending angle deformation inherent strain θ _v obtained in step S7 are obtained. Based on this, welding deformation analysis is performed. That is, the deformation amount of the welded structure is obtained by applying an inherent strain to the weld as an external force. In this way, in step S10, it is possible to estimate the welding deformation of the welded structure in consideration of the influence of restraint.

The above-described inherent strain database stores parameters for determining the inherent strain, mathematical formulas for obtaining the inherent strain based on the parameters, and a relationship diagram. The parameters for determining the inherent strain include welding current A which is a welding condition, welding voltage V, welding heat input Q ₀ calculated from welding speed mm / s, plate thickness h having unit mm, welding method, joint The type, material, and weld length L in units of mm are included. Intrinsic distortion database in restraint under for predicting lateral corner deformation further bending comprising a degree of restraint K _B.

The conversion efficiency η from electrical energy to heat energy given to the weld varies depending on the welding method. The inherent strain varies depending on the thermal history of the weld. For example, the butt joint conducts heat in two directions and the T fillet joint conducts in three directions, so the cooling rate differs depending on the joint type, and therefore the inherent strain differs depending on the joint type. . Welding heat input _{Q 0,} welding method, and from the joint format, Motomari is the effective heat input _{Q net Non,} from this the effective amount of heat input _{Q net Non} and the plate thickness h, the heat history is obtained.

  The linear expansion coefficient, the elastic coefficient, and the thermal conductivity are determined depending on the material. The larger the linear expansion coefficient, the larger the deformation amount. The elastic coefficient and the thermal conductivity also affect the deformation amount. For example, aluminum alloy or stainless steel produces nearly twice the deformation of mild steel. When the weld length L is short, the amount of deformation gradually increases according to the weld length L. When the weld length L is longer than several hundred mm, the amount of deformation becomes a constant value. Lateral bending angle deformation is greatly affected by restraints, particularly bending restraints.

The longitudinal shrinkage inherent strain g _x is determined by the function F ₁ (Q _net , h, L: material), but for each material, a welding length is calculated using a mathematical formula and a relationship diagram showing the relationship between Q _net and g _x * h. It is obtained by correcting according to L. Transverse shrinkage intrinsic distortion _{g y,} the function _{F 2 (Q net, h,} L: Material) is determined by, the formula and using a relationship diagram showing the relationship between _Q net / ^{h 2} and _{g y} for each material, weld length It is obtained by correcting according to L. Although the longitudinal bending angle deformation inherent strain θ _x is determined by the function F ₃ (Q _net , h, L: material), welding is performed using a mathematical expression and a relationship diagram showing the relationship between Q _net and θ _x * h for each material. The correction is made according to the length L. Horizontal bend deformation intrinsic distortion theta _v, the function _{G (Q net, h, K} B, L: Material) is determined by a _Q net / ^{h 2} for each material, the formula showing the relationship between theta _{v, K B} relationship Using a figure, it calculates | requires by correct | amending according to the welding length L. FIG.

  FIG. 4 is a diagram showing an example of a relationship diagram for obtaining the inherent strain. 4 (a) is a diagram related to longitudinal contraction, FIGS. 4 (b) and 4 (c) are diagrams related to lateral contraction, and FIGS. 4 (d) and 4 (e) are lateral bending angle deformations. It is a figure related to.

FIG. 4A is an example of a diagram showing the relationship between the welding heat input Q _net and the tendon force, which is a restraining force generated when restraining longitudinal contraction. Longitudinal shrinkage is inherent distortion of the weld line direction, that is, since caused by longitudinal shrinkage inherent strain _{g x,} it handled using Tendon Force converted inherent strain to stress. It can be seen that the vertical axis is Tendon Force F (N) and the horizontal axis is welding heat input Q _net (J / mm), and Tendon Force F is substantially proportional to welding heat input Q _net .

FIG. 4B is an example of a diagram illustrating the relationship between the welding heat input Q _net and the lateral shrinkage S. The vertical axis is the value obtained by dividing the lateral shrinkage S by the plate thickness h, the horizontal axis is the value obtained by dividing the welding heat input Q _net by the square of the plate thickness h (J / mm ³ ), and S / h is Q _net / it can be seen that is approximately proportional to h ^2. FIG. 4C is an example of a diagram showing the relationship between the welding length L and the lateral shrinkage S. The vertical axis is the value obtained by dividing the lateral shrinkage S by the lateral shrinkage S _∞ when the welding length L is infinite, the horizontal axis is the welding length L (mm), and the ratio S / S _∞ of the lateral shrinkage is the weld length In a range where L is short, the deformation amount increases according to the welding length L, and when the welding length L becomes longer than several hundred mm, the deformation amount becomes a substantially constant value.

FIG. 4D is an example of a diagram illustrating the relationship between the welding heat input Q _net and the lateral bending angle deformation θ. The vertical axis is the horizontal bending angle deformation θ (radian), the horizontal axis is the value (J / mm ³ ) obtained by dividing the welding heat input Q _net by the square of the plate thickness h, and Q _net / h ² is the maximum around 10 J / mm. The value of 0.012 radian is shown. FIG. 4E is an example of a diagram illustrating the relationship between the weld length L and the lateral bending angle deformation θ. The vertical axis is the value obtained by dividing the lateral bending angle deformation θ by the lateral bending angle deformation θ _∞ when the welding length L is infinite, the horizontal axis is the welding length L (mm), and the angular deformation ratio θ / θ _∞ is When the weld length L is short, the amount of deformation increases according to the weld length L. When the weld length L is longer than several hundred mm, the amount of deformation becomes a substantially constant value.

FIG. 5 is a diagram schematically showing a procedure when the deformation estimation method according to the present invention is applied. The actual structure 20 shows a case where the four corners of the member 21 to be welded by the fillet joint are locally restrained by the restraining jigs 23 a to 23 d and welded along the welding line 22. The upper diagram is a diagram viewed from above the member 21, and the lower diagram is a diagram viewed from the side of the member 21. In the bending constraint degree calculation analysis 30, when a uniform moment is loaded in the state of the actual structure 20, the groove angle is analyzed by analyzing a bending moment necessary for bending the unit angle, for example, 1 radian. Calculate for each position. At reference marks 40 to determine the bending degree of restraint K _B at weld lines each portion in the real structure of the bending moment.

In the welding test 50 using a small test plate, a welding test is performed using the small test plate 51, and the inherent strain under constraint is obtained. In this case, the small test plate 51 is welded along the weld line 52 using the welding rod 54 in a state where the restraint jigs 53a and 53b are uniformly bent and restrained, and the welding heat input Q and the member plate thickness. h, and the bending degree of restraint K _B to the parameter, to measure the transverse bend deformation amount θ when releasing the restraint. The value of the bending degree of restraint K _B can be varied by changing the width W of the member, degree of restraint K _B bending to reduce the width W of the member increases.

The constraint inherent strain database 60 stores the measurement results measured in the welding experiment 50 using a small test plate as a graph. This graph is the relationship between the welding heat input Q and transverse bend deformation amount theta, a graph of the bending degree of restraint K _B as parameters. Horizontal bend deformation of theta, has a maximum value by the value of the welding heat input Q, decreases further bent to increase the degree of restraint K _B.

At reference marks 70, the welding heat input Q in the real structure 20, the plate thickness h, and flexural be determined the degree of restraint K _B, the angular deformation of the stored in the constraint under inherent strain database 60 graph, that is, the inherent strain is determined The deformation amount of the welded structure is estimated by applying the inherent strain to the weld line of the model in which the constraint of the actual structure 20 is released and performing the welding deformation analysis.

  In the above-described embodiment, the deformation estimation method using the degree of bending restraint has been described. However, when reverse strain is applied to the plate or pipe to be welded, that is, when tensile stress acts on the surface to be welded. It can also be applied to. In the case of reverse strain, since there is no constraint, the deformation after welding can be obtained by calculation. In this case, the amount of reverse strain can be calculated by changing the amount of reverse strain so that the shape after welding has no deformation, that is, a shape to which no reverse strain is applied.

  FIG. 6 is a diagram for explaining prevention of deformation after welding using the inverse strain method. FIG. 6 (a) shows the case of a butt joint. The lateral bending angle deformation amount at which the welded structure becomes flat after welding is estimated, and the members 80a and 80b are set to an angle corresponding to the estimated deformation amount. That is, welding is performed with reverse strain applied. After welding, the members 80 a and 80 b are joined in parallel on the left and right of the welded portion 81. FIG. 6 (b) shows the case of a fillet joint. As in FIG. 6 (a), the lateral bending angle deformation amount at which the lower member 82a becomes flat after welding is estimated, and the member 82a is estimated. Deformation is performed at an angle corresponding to the amount of deformation, that is, reverse strain is applied and welding is performed. After the member 82b is welded and joined, the member 82a is not deformed.

In order to predict the amount of deformation caused by welding when reverse strain is applied, welding experiments are performed using a small test plate, and the inherent strain when reverse strain is applied is determined and stored in a database. It is possible to estimate in consideration of the effect when measures are taken to control or suppress. When estimating the welding deformation under constraint, it was used bending degree of restraint K _B as a parameter, in the opposite case distortion can be achieved by using a crimping stress sigma _y. In this case, the flow for estimating the welding deformation is the same as the flow shown in FIG. 3 except for step S7. When reverse strain is applied, G ″ (Q _net , h, σ _y , L: material) is used as a function in step S7.

Any of the above-described deformation estimation methods can be realized as a program that causes a computer to execute each deformation estimation method. The computer includes a CPU (Central Processing Unit) (not shown) that performs various controls and a memory (not shown) used for processing performed by the CPU, such as a ROM (Read Only Memory) or a RAM (Random).
A program that includes the (Access Memory) and causes the computer to execute the deformation estimation method is stored in this memory.

  The program that causes the computer to execute the deformation estimation method only needs to be stored in a computer-readable recording medium. In the above-described embodiment, a memory is used as the recording medium. May be provided and can be read by inserting the recording medium into the recording medium. The program stored in the recording medium may be any configuration that can be accessed and executed by the CPU. Alternatively, it may be configured to read the program, download the read program to a program recording area (not shown), and execute the program. This download program is stored in the ROM in advance.

  When the recording medium is configured to be separable from the computer, the recording medium may be a tape system such as a magnetic tape / cassette tape, a magnetic disk such as a flexible disk / hard disk, or a CD-ROM (Compact Disk-Read Only Memory) / MO ( Optical discs such as Magneto Optical Disk (MD) / MD (Mini Disk) / DVD (Digital Versatile Disk), IC (Integrated Circuit) cards (including memory cards) / optical cards, etc., or mask ROM / EPROM ( Erasable Programmable Read Only Memory) / semiconductor memory such as a flash ROM may be used as long as it is a recording medium that holds a fixed program.

  Welding deformation not only affects the appearance and appearance of the product, but also affects the number of assembly and welding processes for manufacturing the product, and also affects the function and performance of the product, so the deformation is controlled and suppressed. Is an industrially important issue. The purpose of estimating the welding deformation is to control and suppress the deformation, for example, to eliminate the groove gap and misunderstanding at the time of block assembly, that is, eliminate the deformation correction work in each process, and the assembly man-hour and welding man-hour Is to guarantee performance by minimizing and providing products with the required dimensional accuracy.

  The conventional simple analysis method using the inherent strain can predict the rough deformation amount of large structures and is effective for some purposes, but it is not sufficient for simulation to suppress welding deformation. is there. In order to suppress welding deformation, it is effective to optimize welding heat input, that is, the amount of heat applied during welding, for example, minimize welding heat input and change the plate thickness. It is possible to consider. However, increasing the plate thickness is difficult to apply because it increases the weight of the product and also increases the material and manufacturing costs. Controlling welding heat input is not practical because the range in which the amount of heat input can be changed is limited due to productivity, manufacturing costs, equipment restrictions, and the like. Only the examination of the joint type change is a method that can be examined by the conventional analysis method.

  Practical deformation control methods are (1) change of assembly and welding procedure, (2) deformation control by restraining jig, (3) application of reverse strain method, (4) change of member size and shape, for example, For example, stretching and R change. The deformation estimation method according to the present invention is effective for (2) and (3), which have a large effect of suppressing welding deformation.

  The deformation estimation method according to the present invention can be applied to the following cases. In the first application example, a veneer used for a ship is produced on a dedicated line using a restraining jig, then several veneers are assembled to produce a small block, and further a small block is assembled to form a solid block. This is the case of manufacturing.

  FIG. 7 is a diagram for explaining a ship block veneer method to which the deformation estimation method according to the present invention is applied. In this ship block veneering method, the skin plate 90 is cut by the cutting device 91 in the first step, the single plate 93 is assembled from the skin plate 90 and the longi material 92 by the assembly device 94 in the second step, and welded in the third step. The long material is welded by the device 95. In the dedicated lines for the first to third steps, a single plate 93 having a standard size is continuously manufactured. At this time, the lateral bending angle deformation of the single plate 93 is constrained using a dedicated jig. In the fourth step, a plurality of single plates 93a to 94d are welded and joined by a welding device 96 to produce a small block 98, a transformer material 97 is inserted into the small block 98 in a fifth step, and a welding device 99 is used in a sixth step. The transformer material 97 is welded.

  For example, a skin material having a length of 10 m and a width of 2 m, that is, a single plate 93 is manufactured by performing fillet welding with three longi materials 92 on a skin plate 90, and using the three single plates 93, a length of 10 m When a small block having a width of 6 m is manufactured, welding deformation can be reduced by applying a reverse strain to a constant plate which is a processing table on which the single plate 93 is placed and performing welding. If a small block with good dimensional accuracy can be manufactured, when assembling a three-dimensional block, the gap between the assembly gap and the mistake is reduced, and the number of assembly steps is reduced and welding automation is facilitated. In order to estimate the welding deformation of a single plate and to estimate the welding deformation of a small block produced by applying reverse strain, it is essential to perform a simulation using the deformation estimation method according to the present invention, which can take into account welding deformation under restraint. .

  As a second application example, there is a case where an upper structure such as a railway vehicle structure or a ship cabin and a living room is manufactured. The railway vehicle structure has a thin plate structure of aluminum or stainless steel, for example, a thin plate structure with a plate thickness of 1.5 to 3 mm. This railway vehicle structure is not only limited to the vehicle critical dimensions but also has no direct relationship with performance, but the passengers are required to have a beautiful appearance without unevenness. The upper structure of the ship also has a thin plate structure, for example, a thin plate structure with a thickness of 4.5 to 6 mm, and has the same problems as the vehicle structure. Specifically, in the thin plate structure, deformation of the horse's spine-shaped outer plate occurs at the joint portion with the aggregate, so that the deformation is reduced by reducing welding heat input, intermittent welding, or spot welding.

FIG. 8 is a diagram for explaining correction of welding deformation of a thin plate panel by local heating. FIG. 8A shows that when the thin plate panel 200 is bent by welding the thin plate panel 200 to the aggregates 201 and 202 with the welding line 203, correction is performed by spot burning, that is, the heating point 204 is overheated by the burner 205. It shows where to correct. FIG. 8B shows the position of the back baking and the heating sequence when the deflection is corrected by back baking when the deflection δ ₁ and the deflection δ ₂ are both bent in the same direction. When δ ₁ is larger than δ ₂ , back baking is performed in the order of the numbers given from the one with the largest deflection. FIG. 8 (c) shows the position and heating order when the deflection is corrected by Matsuba grilling and back grilling when adjacent deflections are in the opposite direction.

  In order to reduce the deflection, welding heat input is reduced, intermittent welding, or spot welding is performed, but it is difficult to reduce the deformation to an allowable level or less, and strain removal work after welding is difficult. This is an indispensable situation. In order to eliminate the strain removing operation, it is effective to suppress the lateral bending angle deformation using a restraining jig, and a simulation by the deformation estimation method according to the present invention that can take this into consideration is essential.

  As a third application example, there is a case where a bogie for a railway vehicle is manufactured. Railcar bogies are important structures that require fatigue strength, and require strict dimensional accuracy. This carriage has a plate welded assembly structure or a pipe structure, and the shape is corrected by on-line heating, baking, etc. at each stage of the welding assembly. However, since it has a thick plate structure as compared with the hull block, a large load is required to constrain the deformation, and the design of the restraining jig is a major issue to constrain the deformation. By using the deformation estimation method according to the present invention, the bending deformation degree within the allowable dimensional accuracy is clarified by the welding deformation simulation under the restriction, and the capacity of the restraining jig, for example, the hydraulic jack is determined according to the bending restriction degree. Capability or rigidity of the restraining jig can be determined.

  As a fourth application example, there is a case of welding a boiler pipe or the like. In the boiler header structure, many pipes for heat exchange with a small diameter are welded to a relatively large diameter main pipe. Since the mother pipe is located at the end of the boiler structure, a large number of small-diameter pipes are attached by welding in a certain direction and within a certain range of the mother pipe. Therefore, the mother pipe is deformed and warps.

  FIG. 9 is a diagram illustrating the structure of the boiler header. A plurality of small-diameter pipes 211 are joined to the mother pipe 210 by welding in substantially the same direction and at short intervals. In such a case, a deformation that bends to the side on which the mother pipe 210 is welded occurs. When deformation occurs in the mother pipe 210, for example, it cannot be installed in a narrow boiler, so that distortion correction is essential. As a method of reducing this, it is possible to restrain deformations from each other by welding the two mother pipes back to back using the restraining jig shown in FIG. 2 (g). . This construction method is also a kind of inverse strain method or load loading method, and it is possible to estimate the amount of deformation using the deformation estimation method according to the present invention.

  FIG. 10 is a diagram for explaining an example in which a welding deformation estimation method using an inverse strain method is applied. As a fifth application example, an example in which the reverse strain method is applied when welding to a pipe is shown. When the tube 220 is welded along the weld line 221, the tube 220 is deformed. In order to restrain this deformation, the pipe 220 is pushed up by two hydraulic jacks 222a and 222b. Also in this case, it is possible to calculate how much restraint needs to be applied by the hydraulic jack by estimating the amount of deformation using the deformation estimation method for applying reverse strain according to the present invention.

It is a figure for demonstrating the kind of welding deformation. It is a figure for demonstrating the restraining jig | tool used in order to suppress the deformation | transformation by welding. It is a figure which shows the flow at the time of estimating a welding deformation | transformation with the deformation | transformation estimation method using the bending constraint which is one Embodiment of this invention. It is the figure which showed the example of the relational diagram for calculating | requiring an intrinsic distortion. It is the figure which represented typically the procedure when applying the deformation | transformation estimation method by this invention. It is a figure for demonstrating prevention of the deformation | transformation after welding using a reverse strain method. It is a figure for demonstrating the ship block veneer method to which the deformation | transformation estimation method by this invention is applied. It is a figure for demonstrating correction of the welding deformation of the thin plate panel by local heating. It is a figure which shows the structure of a boiler header. It is a figure for demonstrating the example which applies the welding deformation estimation method by a reverse strain method. It is a figure which shows the flow at the time of estimating welding deformation using the conventional intrinsic strain.

Explanation of symbols

21, 80, 82 Member 22, 52 Welding line 23, 53 Restraint jig 51 Small test plate 54 Welding rod 81, 83 Welding portion 90 Skin plate 91 Cutting device 92 Longage material 93 Single plate 94 Assembly device 95, 96, 99 Welding Device 97 Transformer material 98 Small block 100, 102, 103, 110, 122, 130, 131 Member 101, 113, 117, 123 Weld line 111, 114, 118, 119, 132 Strong back 112 Thin plate 116 Thick plate 124, 141, 142, 154, 155 Restraint jig 150, 151 Mother pipe 152, 153 Small diameter pipe 200 Thin panel 201, 202 Aggregate 203, 221 Weld line 204 Heating point 205 Burner 206 Water hose 210 Mother pipe 211 Small diameter pipe 212 End plate 220 Pipe 222 hydraulic jack

Claims (3)

Target structure that is the structure of the member to be welded, joint type that indicates the joining type of the member, plate thickness h of the member, welding length L that is the length to be welded, welding method, welding heat input Q that indicates the amount of heat applied during welding ₀ , and a first step of designating the material of the member to be welded;
Based on the inherent strain database that stores the value of the inherent strain obtained in the experiment, the longitudinal shrinkage inherent to the plate thickness h, joint type, weld length L, welding method, welding heat input Q ₀ and material specified in the first step. A second step of obtaining a strain g _x , a transverse contraction inherent strain g _y and a longitudinal bending angle deformation inherent strain θ _x ;
Object structure specified in the first step, based on the joint type and thickness, a third for calculating the by elastic analysis, the joint of each part by the bending moment M given uniformly to the weld line bending degree of restraint K _B Process,
Based on the information stored in the inherent strain database, the thickness h, joint type, weld length L, welding method, welding heat input Q ₀ and material specified in the first step, and the bending calculated in the third step A fourth step of obtaining a lateral bending angle deformation inherent strain θ _v under the constraint by the constraint degree K _B ;
The longitudinal shrinkage intrinsic strain g _x , the transverse shrinkage intrinsic strain g _y obtained in the second step , the longitudinal bend angular deformation intrinsic strain θ _x and the transverse bend angular deformation intrinsic strain θ _v obtained in the fourth step are applied as external forces to the weld. And a fifth step of obtaining a deformation amount of the welded structure by elastic analysis in a state where the restraining jig is released . A program for causing a computer to execute the deformation estimation method according to claim 1 . A computer-readable recording medium on which the program according to claim 2 is recorded.

Images