JP5343052B2 - Structure analysis method, program, and analysis apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce calculation load in a numerical analysis. <P>SOLUTION: In an analysis model generation method in an analyzer for executing a numerical analysis to data of a structure, the analyzer makes a prescribed area of the data of the structure as a solid element model 31, which is a solid element aggregate, and makes an area different from the solid element model 31 as a shell element model 32, which is a shell element aggregate. Then, the solid element model 31 and the shell element model 32 are combined together, thereby generating a composite element model 30. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to an analysis model generation method, a structure analysis method, a program, and an analysis apparatus.

  When a large structure is manufactured by welding, welding deformation occurs due to heat accumulation in the vicinity of the weld and subsequent cooling. In order to reduce such welding deformation, attachment of a restraining jig or correction work after welding is usually performed. Under such circumstances, it is extremely important to predict the deformation by numerical analysis such as the finite element method and to optimize the deformation countermeasure in order to improve the production efficiency and reduce the cost.

  There are two methods of analysis of welding deformation by the finite element method: thermal elastic-plastic analysis and intrinsic strain method. Welding deformation analysis by thermal elastic-plastic analysis is based on unsteady heat conduction analysis of the heat history during welding in the welded structure to be analyzed, and then the displacement during welding by thermal elastic-plastic analysis, which is nonlinear analysis, This is a method of analyzing the history of strain and stress.

  On the other hand, the analysis of welding deformation by the inherent strain method is a method in which the inherent strain generated in the welded portion and its vicinity is given to the welded structure, and the welding deformation is calculated by (thermal) elastic analysis which is linear analysis.

In order to estimate the welding deformation and residual stress of a welded structure using the thermoelastic-plastic analysis method, analysis using a two-dimensional solid element analysis model (two-dimensional model) or a three-dimensional solid element analysis model (3 Analysis using a (dimensional model). In the analysis using a two-dimensional model, it is expected to reduce the calculation time and cost, but the analysis cannot be simulated because the shape of the actual structure, the restraint conditions, the movement of the welding heat source and the formation process of the weld metal cannot be simulated. There is a problem that accuracy is deteriorated. On the other hand, in the case of a three-dimensional model, analysis accuracy is improved. However, since a large model calculation time is required for a large structure, there are many cases where it cannot be calculated practically.
Here, the solid element is an element obtained by dividing a three-dimensional analysis model by a mesh, and the shell element is an element obtained by dividing a two-dimensional analysis model by a mesh.

Under such circumstances, an analysis method that has high calculation accuracy and can reduce calculation time is desired.
In Patent Document 1, the analysis accuracy is high by performing thermoelastic-plastic analysis using a two-dimensional model using the result of thermal deformation obtained by performing thermoelastic analysis using a three-dimensional model as a deformation constraint. Further, a welding residual stress analysis method and a welding residual stress analysis program capable of reducing calculation time are disclosed.

  In Patent Document 2, in the simulation of a vehicle collision, two plates to be welded are modeled as shell elements, and the welded part is modeled as a solid beam element, and the transmission force acting on the weld is calculated, and welding is performed. A break determination device and method for determining breakage of a part are disclosed.

  In Patent Document 3, in calculating a pipe making process by numerical analysis, first, a three-dimensional deformation history of a steel sheet is calculated using a shell element for an analysis model of a composite element including the entire pipe forming process. A numerical analysis method for a pipe making process is disclosed in which a calculation using a solid element is performed on a local model using a calculation result other than the thickness direction obtained as a constraint.

JP 2009-36669 A JP 2005-205467 A JP 2008-176535 A

  If the technique described in Patent Document 1 is used, the one that performs the thermoelastic-plastic analysis is a two-dimensional model, so that the calculation time can be shortened. However, there are many cases in which the two-dimensional model cannot be applied to welding deformation of a complicated large structure, and there is a problem that application is limited.

  If the technique described in Patent Document 2 is used, the analysis time can be shortened by applying both the solid element and the shell element, and the stress of the welded part can be calculated. However, a method for calculating the stress and deformation generated by the thermal history of welding has not been presented.

  If the technique described in Patent Document 3 is used, the calculation time can be shortened because the shell element is applied to the analysis model of the entire pipe making. However, with regard to the welding deformation analysis, when the shell element is applied to the entire analysis, there is a problem that the heat transfer analysis required for calculating the heat history of welding cannot be performed.

  In view of the above circumstances, an object of the present invention is to reduce the calculation load of numerical analysis.

In order to solve the above-described problem, the present invention provides a structure analysis method in an analysis apparatus that performs numerical analysis of a welded structure, and the analysis apparatus includes a predetermined portion in a welded portion of the structure data. The region is a solid element model that is a collection of solid elements, and a region different from the solid element model is a shell element model that is a collection of shell elements. A heat transfer analysis for calculating a heat distribution is performed, and a composite element model is generated by combining the solid element model including the result of the heat transfer analysis and the shell element model, and for the generated composite element model The thermal elastic-plastic analysis for calculating the strain distribution and the stress distribution in the composite element model is performed.

  According to the present invention, it is possible to reduce the calculation load of numerical analysis.

It is a figure which shows the structural example of the analyzer which concerns on this embodiment. It is a figure which shows the solid element data as a comparative example. It is a figure which shows the example of the composite element model which concerns on this embodiment. It is a figure which shows the boundary part of the solid element model and shell element model which concern on this embodiment. It is a figure which shows the example of a format of the coupling | bonding of a solid element model and a shell element model. It is a figure which shows another example in the boundary part of the solid element model and shell element model which concern on this embodiment. It is a flowchart which shows the procedure of the welding deformation | transformation analysis process which concerns on this embodiment. It is a table | surface which shows the calculation time and analysis accuracy of the thermoelastic-plastic analysis in this embodiment and a comparative example. It is a flowchart which shows another procedure of the welding deformation | transformation analysis process which concerns on this embodiment (the 1). It is a flowchart which shows another procedure of the welding deformation | transformation analysis process which concerns on this embodiment (the 2).

  Next, modes for carrying out the present invention (referred to as “embodiments”) will be described in detail with reference to the drawings as appropriate.

(Constitution)
FIG. 1 is a diagram illustrating a configuration example of an analysis apparatus according to the present embodiment.
The analysis apparatus 1 includes a processing unit 10 that processes information, an input unit 20, an output unit 30, and a storage unit 40 that stores CAD (Computer-Aided Design) data and the like.
The processing unit 10 has a function of processing information, and includes a model generation unit 11 and an analysis unit 12.

  The model generation unit 11 generates, for example, a three-dimensional analysis model (three-dimensional model) of a welded structure from CAD data stored in the storage unit 40, or processes the model according to an input from the input unit 20. To do. In the model generation, the shape to be analyzed is acquired from the CAD data, and the mesh in the model is generated according to the mesh configuration designated by the input from the input unit 20. If CAD data is acquired, for example, the position occupied by the welded structure to be analyzed is a coordinate value of three-dimensional coordinates set in advance in the model (in this embodiment, the coordinate axes are assumed to be orthogonal). And the physical property value of the substance constituting the part located at the coordinate value is determined and stored in the storage unit 40. The physical property value is acquired from CAD data.

Further, the model generation unit 11 generates, for example, a mesh in a solid element described later (generation of a solid element model), a mesh in a shell element (generation of a shell element model), and a composite element by combining the solid element and the shell element. It also performs processing such as model generation and setting of node constraint conditions in the mesh.
The generated models (solid element model, shell element model, and composite element model) are stored in the storage unit 40.

  The analysis unit 12 performs numerical analysis on each generated model and outputs the analysis result. The numerical analysis performed in the present embodiment includes, for example, heat transfer analysis, thermoelastic-plastic analysis that is nonlinear analysis, elastic analysis that is linear analysis, analysis by an inherent strain method, and the like.

  The input unit 20 is, for example, a mouse or a keyboard that receives a user operation, and is an input interface that inputs information input from the user to the analysis apparatus 1.

  The output unit 30 is a display that displays, for example, CAD data of a welded structure to be analyzed, a model thereof, a calculation result of numerical analysis, and the like, according to a command (including a drawing command) from the processing unit 10 Also includes an output interface for displaying images.

  The CAD data stored in the storage unit 40 is three-dimensional data generated by designing a welded structure to be analyzed by CAD. The CAD data includes physical property values indicating the physical properties of the welded structure. CAD data may be acquired from an external device via a communication interface (not shown).

  Here, the parameters used for model generation and analysis are the initial conditions related to the mesh configuration (eg, the number, size, and shape of the mesh to be used), the solid element model defined when forming the local model to which the solid element is applied, and For example, the position of the boundary with the shell element model. The values and conditions necessary to perform numerical analysis are the heat source distribution equation that can simulate the thermal history, the heat input, the boundary condition between the analysis target and the surrounding environment, and the mesh node constraint conditions (eg, the constraint target Mesh nodes and the direction in which the nodes are constrained (at least one of the X, Y, and Z directions).

  Note that “restraint” of the nodes of the mesh means that the displacement amount of the nodes is made zero even if numerical analysis is performed. This constraint determines the position reference in the numerical analysis. In a three-dimensional model, at least six degrees of freedom are required for numerical analysis. However, the position and direction of the node to be restrained are not limited.

  Note that the processing unit 10, the model generation unit 11 and the analysis unit 12 in the processing unit 10 store a program stored in a ROM (Read Only Memory) or HDD (Hard Disk Drive) (not shown) in a RAM (Random Access Memory). It is implemented and implemented by being executed by a CPU (Central Processing Unit).

(Description of model)
Next, with reference to FIGS. 2 to 6, a model used for analysis in the present embodiment will be described.
FIG. 2 is a diagram showing solid element data (three-dimensional model) as a comparative example.
2 to 6, the welded structure to be subjected to numerical analysis is configured by linear welding of a welded plate material 21a and a welded plate material 21b. The welded portion 22 with the plate materials 21a and 21b to be welded is a weld metal portion generated by welding.
Until now, as shown in FIG. 2, the solid element model 20 is applied to the entire area of the welded plate material 21a and the welded material 21b, and the numerical analysis is performed on the solid element data 20 generated by setting the mesh. It was. In FIG. 2, a hexahedral mesh is applied to the solid element.

  In FIG. 2, since the welded portion 22 needs to perform numerical analysis with high accuracy, a finer mesh than the surroundings is generated, and the region where the plastic strain is generated by welding (welding vicinity region) is as accurate as the welded portion 22. Since numerical analysis is not required, a slightly coarser mesh is generated from the welded portion 22, and a coarser mesh is generated in a region where no plastic strain occurs than in a region near the weld.

FIG. 3 is a diagram illustrating an example of the composite element model according to the present embodiment. 3 to 6, the same components as those in FIG. 2 are denoted by the same reference numerals and description thereof is omitted.
FIG. 3 is obtained by converting the same structure as FIG. 2 into a composite element model according to the present embodiment. The composite element model 30 is generated by combining a solid element model 31 and shell element models 32a (32) and 32b (32). Here, the region including the welded portion 22 and its vicinity in FIG. 2 including the region where plastic strain occurs (region near the weld) is the solid element model 31, and the other portion (region where no plastic strain occurs) is Shell element models 32a and 32b are used.

  The mesh division in the solid element model 31 is determined by the user in consideration of actual welding conditions and the weld bead cross-sectional shape, and is input to the analysis apparatus 1 via the input unit 20. As the shape of the mesh, a hexahedron with high analysis accuracy is preferably used, but a tetrahedron, a triangular prism, or the like, or a mixed element thereof may be used.

The mesh division of the shell element model 31 in the present embodiment is determined by the user in consideration of the shape of the actual structure and the mesh shape of the solid element model 32 and is input to the analysis apparatus 1 via the input unit 20. The mesh shape is preferably a quadrilateral with high analysis accuracy. Further, an axially symmetric shell element, a triangle, or a mixed element thereof may be used.
Reference numerals 35 to 37 will be described later.

FIG. 4 is a diagram showing a boundary portion between the solid element model and the shell element model according to the present embodiment.
This boundary portion includes a boundary surface 41 of the solid element model 31 and a boundary line 42 of the shell element model 32. The node 43 belonging to the boundary line 42 of the shell element model 32 also belongs to the solid element model 31. That is, all the nodes 43 on the boundary line 42 of the shell element model 32 that contacts the boundary surface 41 of the solid element model 31 belong to both the solid element model 31 and the shell element model 32.

  Note that the position of the boundary line 42 with respect to the boundary surface 41, that is, where the shell element model 32 is connected to the boundary surface 41 is determined according to a preset condition. Connected along.

  In this way, by connecting the shell element model 32 and the solid element model 31 vertically, it is easy to continuously perform numerical analysis over the shell element model 32 and the solid element model 31.

FIG. 5 is a diagram showing a format example of the combination of the solid element model and the shell element model.
5A, in the same way as FIGS. 3 and 4, the normal direction 46 of the boundary surface 41 of the solid element model 31 and the normal direction 45 of the boundary line 42 of the shell element model 32 form a right angle. This is an example. That is, the shell element model 32 is vertically coupled to the solid element model 31 at the boundary portion.

  FIG. 5B is a diagram illustrating an example when the shell element model 32 forms a curved surface. Thus, even if the shell element model 32 forms a curved surface, the normal direction 46 of the boundary surface 41 of the solid element model 31 may be perpendicular to the normal direction 45 of the shell surface at the boundary line 42. That's fine.

  As shown in FIG. 5C, the normal direction 46 of the boundary surface 41 of the solid element model 31 and the normal direction 47 of the shell surface at the boundary line 42 of the shell element model 32 do not form a right angle. Also good. That is, the shell element model does not have to form a right angle with respect to the solid element model 31. However, the boundary surface of the solid element model 31 is shown in FIGS. 5A and 5B in that numerical analysis over the shell element model 32 and the solid element model 31 can be easily performed continuously. It is preferable to combine the solid element model 31 and the shell element model 32 so that the normal direction 46 of 41 and the normal direction 45 of the shell surface at the boundary line 42 of the shell element model 32 form a right angle.

FIG. 6 is a diagram showing another example at the boundary between the solid element model and the shell element model according to the present embodiment. In FIG. 6, the same components as those in FIG.
In the example of FIG. 6, the node 61 on the boundary surface 41 of the solid element model 31 and the node 62 on the boundary line 42 of the shell element model 32 are not shared. That is, the node 62 belonging to the boundary line 42 of the shell element model 32 does not belong to the boundary surface 41 of the solid element model 31. Further, the node 61 belonging to the boundary surface 41 of the solid element model 31 does not belong to the boundary line 42 of the shell element model 32. That is, the node 61 is described in the data of the solid element model 31 but is not described in the data of the shell element model 32. Similarly, the setting 62 is described in the data of the shell element model 32 but is not described in the data of the solid element model 31.

As shown in FIG. 4, the nodes 43 and 44 at the boundary belong to both the solid element model 31 and the shell element model 32. For example, a certain range of the same structure is the solid element model 31, This is used when the range is the shell element model 32. On the other hand, as shown in FIG. 6, the node 61 at the boundary of the solid element model 31 does not belong to the shell element model 32, and the node 62 at the boundary of the shell element model 32 belongs to the solid element model 31. The absence is used when, for example, the solid element model 31 and the shell element model 32 are generated separately and later combined.
Also in FIG. 6, the normal direction 46 (FIG. 5) of the boundary surface 41 of the solid element model 31 is perpendicular to the normal direction 45 (FIG. 5) of the shell surface at the boundary line 42 of the shell element model 32. It is preferable to combine the solid element model 31 and the shell element model 32 so as to achieve this.

(processing)
Next, the welding deformation analysis process according to the present embodiment will be described along FIG. 7 with reference to FIG.
FIG. 7 is a flowchart showing a procedure of welding deformation analysis processing according to the present embodiment.

In this process, first, according to the data input by the user via the input unit 20, the model generation unit 11 constructs a three-dimensional model by converting the welding structure to be analyzed into a three-dimensional finite element model.
Next, the user specifies a region to be a solid element in the constructed three-dimensional model, and the model generation unit 11 generates a solid element model by setting the specified region as a solid element model (S101). Here, in order to obtain sufficient analysis accuracy in the subsequent thermo-elasto-plastic analysis, the user can analyze the region where the plastic strain that includes the welded part and its vicinity may occur. Specify as the area of.
And the model production | generation part 11 produces | generates a shell element model by converting the solid element of the area | region of a shell element model into a shell element among three-dimensional models (S102). In the setting of the region of the shell element model, the region that is not a solid element model in the three-dimensional model may be set as the region of the shell element model by the model generation unit 11, or the user An area may be specified.

  The shell element model is set according to the shape, dimensions, constraint conditions, welding conditions, and the like of the actual structure to be analyzed. Generally, it is a range other than the welded portion where plastic strain occurs and its vicinity (region of the solid element model). Further, the size and the number of elements of the mesh may be set by the user via the input unit 20, or may be set as default values in advance.

Then, the model generation unit 11 performs parameter setting for setting the node numbers of meshes in the solid element model and the shell element model.
The solid element model and the shell element model are held in the storage unit 40 as separate data.

Next, the analysis part 12 performs the thermoelastic-plastic analysis of a solid element model according to the procedure of the following steps S103 and S104.
First, the analysis unit 12 sets a solid element of the solid element model as a model part for thermal elastic-plastic analysis. Since this model portion is extracted from the solid element model as it is, the creation of the model and the mesh is limited to one time, and the mesh creation process can be shortened. That is, for the solid element portion, the initially created three-dimensional model can be used as it is.
As solid element extraction parameters, the boundary part of the solid element model and the boundary part of the remaining part (shell element model) of the entire three-dimensional model are acquired and set. That is, when extracting the solid element, the analysis unit 12 also extracts a parameter regarding a boundary portion between the solid element model and the shell element model as a parameter to be used.

  The analysis unit 12 performs heat transfer analysis of the solid element model (S103). As a specific flow of heat transfer analysis, the analysis unit 12 first sets a heat input condition that simulates actual welding conditions, and then performs a thermal analysis of the process from the start of welding to completion at fine time intervals, Calculate the thermal history (heat distribution) close to actual welding. As a result, a history of the temperature distribution of the welded portion and its vicinity (region of the solid element model) is obtained.

  Next, the analysis unit 12 sets a constraint condition for the boundary surface of the solid element model, which is a necessary condition for the next step. This boundary surface is an analytical boundary surface, and such a boundary surface does not exist in an actual structure. In other words, since the actual structural part is a structure having a thick shell part, the portion corresponding to the boundary surface is a continuous structure having a thickness. It exists only on the top.

  Here, the constraint condition of the boundary surface is set in consideration of the constraint condition of the actual structure. In the present embodiment, the displacement amounts in the X, Y, and Z directions, which are the coordinate directions shown in FIG. 6, are set to 0 at all nodes belonging to the boundary surface 41 of the solid element model shown in FIG. That is, the constraint condition is set so that the nodes of the boundary surface 41 are not displaced in any of the X direction, the Y direction, and the Z direction.

  Then, after setting the constraint condition of the boundary surface in the solid element model, the analysis unit 12 uses the analysis result of the thermal history of the solid element model output in the heat transfer analysis in step S103 as an input condition to determine the nonlinearity of the solid element model. The thermal elasto-plastic analysis is performed (S104). The strain history (strain distribution) and stress history (stress distribution) of the solid element model are obtained by the thermoelastic-plastic analysis in step S104.

  After the thermal elastic-plastic analysis of the solid element model in step S104 is completed, the model generation unit 11 combines the solid element model including the strain history information output in step S104 and the shell element model to combine them. An element model is generated (S105). In addition, when the thermal elastic-plastic analysis of the solid element model is performed, the nodes of the boundary surface between the solid element model and the shell element model are constrained, so the connection between the shell element model and the solid element model is easy. realizable. The composite element model generated at this time includes information such as strain history and stress history in the vicinity of the weld obtained by the thermal elastic-plastic analysis of the solid element model in step S104.

  Next, when a constraint condition in consideration of the constraint of the actual structure is given to the mesh node of the composite element model via the input unit 20, the analysis unit 12 executes an elastic analysis of the composite element model ( (S106), the welding deformation of the final structure is calculated (S107).

The processing in step S106 will be described in detail as follows.
That is, the analysis unit 12 releases the constraint condition of the boundary surface of the solid element model set when performing the thermoelastic-plastic analysis of the solid element model, and sets the constraint condition that can simulate the constraint of the actual structure. In the present embodiment, three constraints in the X direction, Y direction, and Z direction are set for the end node 35 of the composite element model in FIG. 3, and the constraints in the Y direction and Z direction are given to the end node 36. A constraint in the Z direction is set at the node 37.

  The analysis unit 12 includes a composite element in which strain history and stress history in the solid element model obtained as a result of the thermoelastic-plastic analysis are included, and new constraint conditions (restraints at the end nodes 35 to 37) are set. Elastic analysis is performed using the model, and the deformation of the structure is calculated. Since the elastic analysis and the calculation of the deformation of the structure are well-known contents, detailed description thereof is omitted.

  In this embodiment, the composite element model is generated after performing the thermal elastic-plastic analysis on the solid element model.However, after generating the composite element model, the welded part and its vicinity are identified from the composite element model. It is also possible to extract a solid element model from a range that requires a thermal elastic-plastic analysis in which plastic strain occurs, and perform a thermal elastic-plastic analysis on the solid element model.

(Comparison of thermal elastic-plastic analysis results)
Next, in order to show the effect of this embodiment, FIG. 8 shows a comparison result between the comparative example, the calculation time of the thermoelastic-plastic analysis using this embodiment, and the analysis accuracy.
The result of the thermo-elasto-plastic analysis in the comparative example shows the result of the thermo-elasto-plastic analysis performed using a model in which the entire region of the structure to be numerically analyzed as shown in FIG. The result of the thermoelastic-plastic analysis in Fig. 3 shows the result of performing the thermoelastic-plastic analysis using a composite element model as shown in FIG.

The structure after welding used for the thermoelastic-plastic analysis in the comparative example and this embodiment has, for example, a length of about 1200 mm, a width of about 600 mm, and a thickness of 12 mm.
The scale of the model in the comparative example is about 100,000 elements and 138,000 nodes. Since welding was performed by one-pass welding using laser / arc hybrid welding, the heat source model used was a combined moving heat source of a linear Gaussian heat source (corresponding to a laser heat source) and a dotted Gaussian heat source (corresponding to an arc heat source). . The heat input conditions of the thermoelastic-plastic analysis were determined in consideration of the actual welding conditions and the weld bead cross-sectional shape.

  After setting the model and welding conditions (heat input conditions) in the comparative example as described above, the thermoelastic-plastic analysis of the solid element data was performed in the same procedure as the thermoelastic-plastic analysis method in the present embodiment.

  On the other hand, the scale of the composite element model in the present embodiment is about 60,000 elements and about 82,000 nodes in total of solid elements and shell elements. Among them, the scale of a solid element model that creates a mesh of hexahedral elements is about 50,000 elements and about 70,000 nodes, and the scale of a shell element model that creates a mesh of quadrilateral elements is about 10,000 elements, 12 About 1,000. Since welding was performed by one-pass welding using laser / arc hybrid welding, a combined heat source of a linear Gaussian heat source (corresponding to a laser heat source) and a dotted Gaussian heat source (corresponding to an arc heat source) was used as the heat source model. The heat input conditions for the analysis were determined in consideration of the actual welding conditions and the weld bead cross-sectional shape.

Under such conditions, thermoelastic-plastic analysis was performed over the entire area of the composite element model in the present embodiment, and the calculation results and analysis accuracy were calculated.
Note that the analysis accuracy indicates how much accurate analysis can be performed compared to the case where all the regions are solid element models.

As a result, a result as shown in FIG. 8 was obtained. In FIG. 8, the value in the comparative example is set to “1” as a reference, and the value in the present embodiment is indicated as a relative value with respect to the value.
First, as for the calculation time per time, if the calculation time in the comparative example is “1”, in this embodiment, the thermo-elasto-plastic analysis can be performed with a calculation time of 0.4 to 0.8. Shortening became possible.
On the other hand, when the analysis accuracy in the comparative example is “1”, the analysis accuracy is 0.6 to 0.9 in the present embodiment, which is slightly lower, but can show a sufficient value as the accuracy. It was.

(Another analysis method)
FIG. 9 is a flowchart showing a procedure of welding deformation analysis processing different from that in FIG. 7 using the composite element model according to the present embodiment. In the procedure shown in FIG. 7, after performing heat transfer analysis and thermoelastic-plastic analysis on the solid element model, a composite element model is generated and thermoelastic-plastic analysis is performed on the composite element model. On the other hand, in the procedure shown in FIG. 9, a heat transfer analysis is performed on a solid element model, and then a composite element model is generated without performing a thermal elastic-plastic analysis on the solid element model. A plastic analysis is performed.

In FIG. 9, steps S201 to S203 are the same as steps S101 to S103 in FIG. 2, respectively.
After step S203, the model generation unit 11 combines the solid element model and the shell element model to generate a composite element model (S204).

Next, the analysis unit 12 gives the result of the heat transfer analysis performed in step S203 to each node element of the solid element model in the composite element model, and further sets an appropriate temperature history for the shell element model. . Specifically, the average temperature history of the nodes belonging to the boundary surface with the shell element model in the solid element model is given to the nodes belonging to the boundary line of the shell element. Further, room temperature (for example, 20 ° C.) is given to the end nodes 35 to 37 belonging to the end of the shell element model as shown in FIG. 3, and the boundary line between the end of the shell element model and the solid element model For other nodes, the temperature is estimated from the end and boundary node temperatures by the insertion method.
Note that the setting of the temperature distribution of the shell element model and the setting of the temperature history of the nodes of the solid element model may be set by the user via the input unit 20 or may be set in advance.

  After the setting of the temperature history, the analysis unit 12 performs a thermoelastic-plastic analysis on the composite element model (S205), and calculates the weld deformation of the structure (S206).

  In the procedure of FIG. 9, after the heat transfer analysis of the solid element model is completed, the thermal elastic-plastic analysis is not performed on the solid element model, and the shell element is included in the solid element model including the heat transfer analysis result (temperature history). The model is combined to generate a composite element model. Unlike the procedure of FIG. 7, the generated composite element model does not include information on strain history and stress history.

According to the procedure shown in FIG. 9, the number of processes can be reduced compared to the procedure shown in FIG. 7 because the thermal elastic-plastic analysis of the solid element model is not executed.
Note that the calculation time and analysis accuracy of the numerical analysis according to the procedure shown in FIG. 9 are comparable to those in the comparison table shown in FIG.

(Another example)
FIG. 10 is a flowchart showing another procedure of the welding deformation analysis process according to the present embodiment.
The procedure shown in FIG. 10 generates a composite element model without performing heat transfer analysis or thermoelastic-plastic analysis on the solid element model, and performs heat transfer analysis and thermoelastic-plastic analysis on the composite element model. Is.

First, steps S301 and S302 in FIG. 10 are the same processes as steps S101 and S102 in FIG.
After step S302, the model generation unit 11 combines the generated solid element model and the shell element model to generate a composite element model (S303).
The generated composite element model does not include the information of the thermal elastic-plastic analysis result as in the procedure of FIG. 7, nor does it include the temperature history information as in the procedure of FIG.

  Next, the analysis unit 12 performs a heat transfer analysis on the generated composite element model (S304). As a specific flow, first, a heat input condition that simulates an actual welding condition is set via the input unit 20. Next, the analysis unit 12 performs a thermal analysis of the process from the start of welding to completion in accordance with the set heat input conditions at fine time intervals, and calculates a thermal history close to actual welding. By such heat transfer analysis, a history of temperature distribution in the welded part and the vicinity thereof is obtained.

  At this time, since the boundary between the boundary line of the shell element model and the solid element model is joined, the temperature history of the nodes of the shell element model can be calculated from the calculation of the solid element model.

  And after completion | finish of the heat transfer analysis in step S304, the analysis part 12 performs a thermoelastic-plastic analysis with respect to a composite element model (S305), and calculates the welding deformation of a structure (S306).

The procedure according to FIG. 10 can also reduce the number of processes compared to the procedure shown in FIG.
Note that the calculation time and analysis accuracy of the numerical analysis according to FIG. 10 are comparable to those of the comparison table shown in FIG.

In the composite element model, two or more boundaries between the solid element model and the shell element model may be formed. That is, two or more shell element models may be coupled to one boundary surface of the solid element model.
Further, in the solid element model, the mesh may be cut in parallel or non-parallel to the mesh surface without being along the mesh surface. When the mesh is formed so as to be cut, a cut surface formed by the cutting may be used as a new mesh surface.
That is, in the present embodiment, the solid element model has a rectangular parallelepiped shape, but the boundary surface may be generated in a step shape, for example.

In this embodiment, the boundary between the solid element model and the shell element model is designated by the user from the input unit 20. That is, the range of the solid element model (or shell element model) is specified by the user via the input unit 20.
However, when setting the position of the boundary between the solid element model and the shell element model, use a program that can set the boundary to achieve the desired analysis calculation time and desired analysis accuracy. Also good. That is, the range of the solid element model (or shell element model) is determined by the processing unit 10 based on the desired calculation time input via the input unit 20. The size may be calculated and the range of the solid element model (or shell element model) may be automatically specified.

(Summary)
According to the present embodiment, the welded part and the vicinity of the welded part are analyzed as a solid element model, and the other parts are used as a shell element model, so that important parts can be calculated while maintaining the analysis accuracy with the solid element model. The load can be reduced.

DESCRIPTION OF SYMBOLS 1 Analysis apparatus 10 Processing part 11 Model production | generation part 12 Analysis part 20 Input part 30 Output part 40 Storage part 30 Composite element model 31 Solid element model 32 Shell element model 43, 61, 62 Node 45, 46 Normal

Claims (6)

A structure analysis method in an analysis apparatus for performing numerical analysis of a welded structure,
The analysis device includes:
Among the data of the structure, a predetermined region in the welded portion is a solid element model that is an aggregate of solid elements,
A region different from the solid element model is a shell element model that is a collection of shell elements,
For the solid element model, perform heat transfer analysis to calculate the heat distribution in the solid element model,
Combining the solid element model including the result of the heat transfer analysis and the shell element model to generate a composite element model;
A structure analysis method, comprising: performing a thermal elastic-plastic analysis for calculating a strain distribution and a stress distribution in the composite element model for the generated composite element model. And the normal at the boundary surface between the shell element model in the solid element model, structure analysis method according to claim 1 in which the normal line on the plane of the shell element model, but wherein the perpendicular . A first node that is a node of the shell element model and is a node on a boundary line with the solid element model; and a second node that is a node of the solid element model and is in contact with the boundary line structure analysis method according to claim 1, characterized in that the, the positions match. . A first node that is a node of the shell element model and is a node on a boundary line with the solid element model; and a second node that is a node of the solid element model and is in contact with the boundary line structure analysis method according to claim 1, characterized in that the, the position does not match. Program for executing the structure analysis method according to the computer in any one of claims 1 to 4. An analysis device for numerical analysis of welded structures,
A model generation unit and an analysis unit;
The model generation unit
Among the data of the structure, a predetermined region in the welded portion is a solid element model that is an aggregate of solid elements,
A region different from the solid element model is a shell element model that is a collection of shell elements,
Combining the solid element model including the result of heat transfer analysis by the analysis unit and the shell element model to generate a composite element model;
The analysis unit
For the solid element model, perform heat transfer analysis to calculate the heat distribution in the solid element model,
An analysis apparatus for performing thermal elastic-plastic analysis for calculating strain distribution and stress distribution in the composite element model for the composite element model generated by a model generation unit.

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